{"name":"选矿工题库","level":"五级/初级工、四级/中级工、三级/高级工、二级/技师、一级/高级技师","org":"人力资源和社会保障部门","count":300,"questions":[{"id":1,"type":"single","stem":"颚式破碎机运行时突然听到金属撞击声且排料口有铁块排出，正确的第一步处置是","options":["立即按下停车按钮并通知值班长","先观察几分钟看是否继续出铁","加大给矿量把铁块顶出来","调整排料口尺寸后再启动"],"answer":[0],"explanation":"知识点是破碎机异物进入的应急处理。正确项：立即停车可防止铁块继续损坏颚板、主轴等部件，并上报。错误项：观察等待会让设备持续受损；加大给矿会把铁块压得更深；调整排料口不能解决异物，且未停车就调整存在安全风险。","tier":"进阶"},{"id":2,"type":"single","stem":"球磨机给矿量不变而溢流粒度突然变粗，最先应检查的运行参数是","options":["分级机溢流堰高度","磨机筒体温度","给矿皮带宽度","润滑油泵型号"],"answer":[0],"explanation":"知识点是磨矿分级闭路中溢流粒度的影响因素。正确项：溢流堰高度决定分级区沉降时间，堰低则溢流粗。错误项：筒体温度主要反映磨矿发热而非粒度；皮带宽度是固定设备参数；油泵型号与粒度无直接关系。","tier":"进阶"},{"id":3,"type":"single","stem":"浮选作业中矿浆pH值突然升高，对黄药类捕收剂浮选硫化矿的常见影响是","options":["捕收能力下降，回收率降低","捕收能力增强，选择性变差","气泡直径变小，泡沫变脆","矿粒疏水性增强，上浮加快"],"answer":[0],"explanation":"知识点是pH对黄药浮选的影响。正确项：高pH下黄药易水解、矿物表面受抑制，捕收力下降。错误项：增强与事实相反；气泡直径主要受起泡剂和充气量影响；疏水性增强不符合高pH抑制规律。","tier":"进阶"},{"id":4,"type":"single","stem":"在浮选流程中，向矿浆中加入石灰的主要作用之一是","options":["调节pH并抑制黄铁矿","提高矿浆温度","增加气泡数量","降低矿浆密度"],"answer":[0],"explanation":"知识点是石灰在浮选中的作用。正确项：石灰提高pH并抑制黄铁矿等硫化铁矿物。错误项：石灰不用于升温；气泡数量由起泡剂和充气决定；石灰不用于降低矿浆密度。","tier":"基础"},{"id":5,"type":"single","stem":"螺旋分级机返砂量突然增大，与下列哪一现象最可能同时出现","options":["磨机排矿粒度变粗","溢流浓度明显降低","磨机给矿量减少","分级机溢流堰升高"],"answer":[0],"explanation":"知识点是磨矿分级闭路中返砂与粒度的关系。正确项：排矿粗则沉砂多，返砂量增大。错误项：溢流浓度降低多与返砂减少或给水增大有关；给矿量减少通常返砂减少；溢流堰升高会使溢流变粗而非返砂增大。","tier":"进阶"},{"id":6,"type":"single","stem":"浮选泡沫层过厚且发黏、精矿品位下降，操作上较合理的调整是","options":["适当降低起泡剂用量并减少充气量","加大起泡剂用量并提高充气量","提高矿浆浓度并增加给矿量","降低矿浆温度并停加捕收剂"],"answer":[0],"explanation":"知识点是浮选泡沫状态与药剂、充气的调节。正确项：泡沫过厚发黏多为起泡剂过量，应减起泡剂并适当减充气。错误项：加大起泡剂会加重问题；提高浓度和给矿量会恶化分选；停加捕收剂会降低回收率且不针对泡沫问题。","tier":"基础"},{"id":7,"type":"single","stem":"某选矿厂铜硫混合精矿分离浮选时，加入石灰后硫精矿品位反而下降，最可能的原因是","options":["石灰用量过大抑制了黄铜矿","石灰用量不足未抑制黄铁矿","石灰与黄药发生反应生成沉淀","石灰提高了矿浆温度"],"answer":[0],"explanation":"知识点是铜硫分离中石灰的抑制作用。正确项：石灰过量会抑制黄铜矿，使铜进入硫精矿导致硫精矿品位下降。错误项：用量不足则黄铁矿进入铜精矿；石灰与黄药反应不是主要原因；石灰不显著升温。","tier":"进阶"},{"id":8,"type":"single","stem":"浮选机运行中矿浆液面突然下降并伴随充气量减小，现场首先应检查的是","options":["充气管道是否堵塞或阀门开度","捕收剂添加泵是否停转","精矿刮板转速是否过快","矿浆pH值是否偏高"],"answer":[0],"explanation":"知识点是浮选机充气与液面的关系。正确项：充气不足会使液面下降，先查充气管和阀门。错误项：捕收剂泵停转主要影响回收率不直接降液面；刮板转速影响精矿排出；pH偏高不导致液面突降。","tier":"挑战"},{"id":9,"type":"multi","stem":"关于磁选作业给矿前预处理的正确做法包括哪些","options":["给矿前筛除粗大杂物和木屑","给矿浓度控制在设备适宜范围","矿浆中混入铁器可提高磁选效率","给矿前适当脱泥可减少脉石夹带","给矿粒度越粗越有利于磁选分选"],"answer":[0,1,3],"explanation":"知识点是磁选给矿预处理要求。正确项：筛除杂物防止堵塞；控制浓度保证分选；脱泥减少脉石夹带。错误项：混入铁器会干扰分选并损坏设备；给矿粒度过粗会使磁性矿粒与非磁性矿粒连生体增多，分选变差。","tier":"进阶"},{"id":10,"type":"single","stem":"颚式破碎机工作时，给矿块度超过给矿口尺寸的多少倍时最容易发生卡块堵料","options":["0.5倍","0.85倍","1.5倍","2.0倍"],"answer":[1],"explanation":"知识点是颚式破碎机给矿块度上限。给矿块度一般不超过给矿口宽度的0.85倍，超过后易卡块堵料。0.5倍偏小属于正常范围；1.5倍和2.0倍均超过给矿口允许上限，属必然卡堵的错误参数。","tier":"进阶"},{"id":11,"type":"single","stem":"圆锥破碎机采用挤满给矿时，给矿应保持的状态是","options":["给矿口始终留有明显空隙","破碎腔内矿石充满且均匀分布","给矿量随电流波动随时增减","只在一侧给矿形成自然堆积"],"answer":[1],"explanation":"挤满给矿要求破碎腔充满矿石并均匀分布，才能形成层压破碎。留有明显空隙是滞料给矿；随电流波动增减给矿会破坏挤满状态；单侧给矿会造成偏析和衬板偏磨。","tier":"基础"},{"id":12,"type":"single","stem":"格子型球磨机与溢流型球磨机相比，在排矿方式上的主要区别是","options":["格子型靠矿浆自流溢过排矿口","格子型经格子板后由提升斗排出","溢流型必须配螺旋分级机排矿","溢流型通过周边筛板强制排矿"],"answer":[1],"explanation":"格子型球磨机矿浆通过格子板进入提升斗排出，排矿速度快、粒度较粗。靠矿浆自流溢过排矿口是溢流型特征；溢流型通常配螺旋分级机但并非必须；周边筛板强制排矿不是溢流型方式。","tier":"基础"},{"id":13,"type":"single","stem":"浮选作业中矿浆pH值偏低时，对黄药类捕收剂在硫化矿表面的吸附通常产生的影响是","options":["促进黄药离子在矿物表面吸附","抑制黄药离子在矿物表面吸附","对黄药吸附没有任何影响","只影响起泡剂用量不影响捕收"],"answer":[1],"explanation":"知识点是pH对黄药捕收的影响。黄药在酸性或弱碱性条件下较易吸附，pH偏低时通常促进吸附，故“抑制吸附”一说不符合常见规律；无影响或只影响起泡剂的说法都忽略了pH对捕收剂解离和矿物表面电性的作用。","tier":"进阶"},{"id":14,"type":"single","stem":"磁选机分选过程中，给矿粒度变粗而其他条件不变时，精矿品位通常的变化是","options":["品位升高，回收率下降","品位下降，单体解离不充分","品位不变，回收率明显升高","品位和回收率同时升高"],"answer":[1],"explanation":"给矿粒度变粗时连生体增多，磁性颗粒与非磁性颗粒未充分解离，精矿品位下降。品位升高与回收率下降通常出现在粒度偏细泥化时；品位不变且回收率升高不符合分选规律；两者同时升高一般需多因素配合，不会仅由粒度变粗引起。","tier":"进阶"},{"id":15,"type":"single","stem":"浮选机刮泡时，泡沫层过厚且发黏，最可能的原因是","options":["起泡剂用量不足","捕收剂或调整剂过量","充气量明显偏大","矿浆浓度明显偏低"],"answer":[1],"explanation":"泡沫层厚且发黏多因捕收剂或调整剂过量，使泡沫过度稳定。起泡剂不足会造成泡沫脆、层薄；充气量偏大会使泡沫层活跃但一般不发黏；矿浆浓度偏低会使泡沫层变薄而非变厚发黏。","tier":"基础"},{"id":16,"type":"single","stem":"某选矿厂球磨机排矿粒度突然变粗，分级机返砂量明显增大，首先应检查的环节是","options":["浮选药剂添加量是否变化","磨机给矿量和水量的配比","磁选机磁场强度是否波动","精矿过滤机真空度是否下降"],"answer":[1],"explanation":"排矿变粗且返砂增大属于磨矿分级回路问题，应先查给矿量与水量配比。浮选药剂、磁选磁场、过滤真空度分别属于后续作业，不会直接造成磨机排矿变粗和返砂增大。","tier":"挑战"},{"id":17,"type":"single","stem":"铜硫混合精矿分离浮选时，常用石灰抑制黄铁矿，其作用机理主要是","options":["提高矿浆pH并使黄铁矿表面亲水","降低矿浆pH并活化黄铁矿","与黄药生成沉淀降低其浓度","增加矿浆温度促进黄铁矿上浮"],"answer":[0],"explanation":"石灰提高矿浆pH，并在黄铁矿表面形成亲水薄膜使其受抑制。降低pH会活化黄铁矿；与黄药生成沉淀不是石灰抑制黄铁矿的主要机理；升高温度促进上浮与抑制目的相反。","tier":"进阶"},{"id":18,"type":"single","stem":"弱磁选机分选强磁性矿物时，给矿浓度突然大幅降低，最可能出现的现象是","options":["精矿品位下降，尾矿跑铁增加","精矿品位升高，回收率下降","精矿品位和回收率均不变","磁系温度迅速升高"],"answer":[0],"explanation":"给矿浓度大幅降低使矿浆流速加快、停留时间缩短，磁性颗粒来不及被吸附，尾矿跑铁增加，同时夹杂减少使品位可能略升，但综合表现为回收率下降。品位和回收率均不变不符合分选规律；磁系温度与给矿浓度无直接关系。","tier":"挑战"},{"id":19,"type":"single","stem":"浮选流程中，粗选精矿再选称为精选，其目的主要是","options":["提高精矿品位","提高原矿处理量","降低磨矿细度","增加尾矿品位"],"answer":[0],"explanation":"精选是对粗选精矿再选，目的是提高精矿品位。提高原矿处理量靠磨浮能力配置；降低磨矿细度是磨矿作业目标；增加尾矿品位是分选变差的表现，不是精选目的。","tier":"基础"},{"id":20,"type":"single","stem":"某选矿厂浮选尾矿品位突然升高，现场检查发现浮选机充气量正常、药剂添加正常，下一步最合理的排查顺序是","options":["先查磨矿细度再查给矿性质变化","先查精矿过滤再查尾矿输送","先查磁选机再查浓缩机","先查皮带秤再查药剂罐液位"],"answer":[0],"explanation":"尾矿品位升高在充气和药剂正常时，多与磨矿细度或给矿性质变化有关，应先查磨矿细度再查给矿性质。精矿过滤、尾矿输送、磁选机、浓缩机、皮带秤与药剂罐液位均不是导致浮选尾矿品位升高的直接原因。","tier":"挑战"},{"id":21,"type":"single","stem":"选矿厂破碎作业中，颚式破碎机排矿口宽度调整后，最先需要复核的运行参数是","options":["给矿粒度上限","设备处理能力","衬板磨损速率","电机绝缘电阻"],"answer":[1],"explanation":"知识点：颚式破碎机排矿口决定产品粒度上限与处理能力。排矿口调小后处理能力下降，需重新核定给矿量，因此最先复核处理能力。给矿粒度上限由原矿决定、不随排矿口改变；衬板磨损速率是长期指标；电机绝缘电阻与排矿口无关。","tier":"基础"},{"id":22,"type":"single","stem":"球磨机给矿量不变而返砂量明显增大、分级机溢流变粗，最可能的原因是","options":["磨机转速偏低","排矿浓度过低","分级机溢流堰偏高","磨机充填率过高"],"answer":[2],"explanation":"知识点：闭路磨矿分级返砂量与溢流粒度关系。溢流堰升高使沉降区变浅、细粒来不及沉降，返砂增大且溢流变粗。转速偏低一般使产品变粗但返砂变化不典型；排矿浓度过低会加剧过磨；充填率过高处理量下降、返砂通常减少。","tier":"基础"},{"id":23,"type":"single","stem":"浮选机刮泡正常但精矿品位持续下降、泡沫层变薄且发脆，优先检查的药剂添加环节是","options":["捕收剂用量是否偏大","起泡剂用量是否偏大","调整剂用量是否偏小","活化剂用量是否偏小"],"answer":[1],"explanation":"知识点：起泡剂过量导致泡沫脆、品位下降。起泡剂过多使泡沫层变薄发脆、选择性变差，精矿品位下降。捕收剂偏大通常泡沫过稳、品位也降但泡沫不发脆；调整剂偏小会改变矿浆pH或抑制效果而非泡沫脆；活化剂偏小一般使回收率下降。","tier":"进阶"},{"id":24,"type":"single","stem":"强磁性矿物用弱磁选机分选时，给矿浓度突然升高，最先出现的现象是","options":["精矿品位下降","尾矿品位升高","磁滚筒转速下降","分选带水膜变薄"],"answer":[1],"explanation":"知识点：磁选给矿浓度对分选效果的影响。浓度升高使矿浆黏度增大、磁性矿粒被非磁性矿粒夹带进入尾矿，尾矿品位先升高。精矿品位变化相对滞后；滚筒转速由传动决定；水膜厚度不直接随浓度骤变。","tier":"进阶"},{"id":25,"type":"single","stem":"一段闭路磨矿中旋流器沉砂口磨损扩大后，对磨矿回路最直接的影响是","options":["分级效率提高","循环负荷降低","磨机处理量上升","沉砂量增大且夹细"],"answer":[3],"explanation":"知识点：旋流器沉砂口磨损对分级的影响。沉砂口扩大使沉砂量增大并夹带细粒返回磨机，循环负荷上升。分级效率下降而非提高；循环负荷上升而非降低；磨机处理量通常下降。","tier":"基础"},{"id":26,"type":"single","stem":"某选矿厂浮选流程中矿返回地点选择时，含连生体较多的中矿应优先返回","options":["粗选作业","精选作业","扫选作业","最终精矿"],"answer":[0],"explanation":"知识点：中矿返回原则。含连生体多的中矿应返回粗选再磨再选，使其有解离机会。返回精选会污染精矿；返回扫选易损失于尾矿；返回最终精矿直接降低品位。","tier":"基础"},{"id":27,"type":"single","stem":"振动筛运行时出现筛孔堵塞、处理量下降，现场正确的处置是","options":["提高给矿速度冲开筛孔","停机清理并检查筛网张紧","加大振幅长时间运行","减少给矿量等待自清"],"answer":[1],"explanation":"知识点：振动筛筛孔堵塞的处置。筛孔堵塞多因筛网松弛或水分高，应停机清理并检查张紧度。提高给矿速度会加剧堵塞；加大振幅长时间运行可能损坏设备；减少给矿量不能解决堵塞。","tier":"挑战"},{"id":28,"type":"single","stem":"磁选机分选效果变差，检查发现磁系偏角调整不当，正确的调整方向是使磁系偏角","options":["沿矿浆流动方向前移","逆矿浆流动方向后移","与滚筒轴线平行","与给矿方向垂直"],"answer":[0],"explanation":"知识点：磁选机磁系偏角调整。磁系偏角应沿矿浆流动方向适当前移，使磁性矿粒在磁场中停留时间延长、分选更充分。后移会缩短分选带；与轴线平行或与给矿方向垂直均不符合磁系布置要求。","tier":"挑战"},{"id":29,"type":"single","stem":"磨矿分级回路中，磨机排矿浓度突然变稀而分级溢流浓度正常，最可能的原因是","options":["给矿量突然增大","补加水阀门开度过大","旋流器沉砂口堵塞","磨机衬板磨损严重"],"answer":[1],"explanation":"知识点：磨机排矿浓度与补加水关系。补加水过大使排矿浓度变稀，但分级溢流因分级作用仍可维持正常。给矿量增大排矿浓度变浓；沉砂口堵塞影响分级而非排矿浓度；衬板磨损影响磨矿效率而非浓度骤变。","tier":"挑战"},{"id":30,"type":"single","stem":"浮选作业中矿浆pH值突然降低，现场操作人员应优先采取的处置是","options":["加大捕收剂用量","检查石灰添加系统","提高浮选机转速","增加刮泡次数"],"answer":[1],"explanation":"知识点：pH异常处置。pH突然降低多因石灰添加中断或调整剂加入异常，应检查石灰添加系统。加大捕收剂不能恢复pH且可能恶化选择；提高转速、增加刮泡与pH异常无直接因果关系。","tier":"进阶"},{"id":31,"type":"single","stem":"某选矿厂球磨机运行中筒体螺栓处出现矿浆渗漏，正确的处置是","options":["继续运行至计划检修","立即停机紧固或更换螺栓","用棉纱临时封堵渗漏点","降低给矿量继续观察"],"answer":[1],"explanation":"知识点：磨机筒体渗漏处置。筒体螺栓渗漏说明紧固失效或密封损坏，应立即停机处理，防止事故扩大。继续运行、临时封堵、降低给矿量观察都会延误处置并可能造成设备损坏。","tier":"进阶"},{"id":32,"type":"single","stem":"颚式破碎机运行中突然听到金属撞击声且排料口有铁块排出，正确的首要处置是立即按停机按钮并通知相关人员，同时应重点检查的部位是","options":["动颚与肘板连接处","给矿溜槽衬板","皮带输送机托辊","除尘风机叶轮"],"answer":[0],"explanation":"知识点：颚式破碎机过铁故障排查。铁块进入破碎腔后冲击力主要作用于动颚、肘板和推力板等传力部件，因此应重点检查动颚与肘板连接处。给矿溜槽衬板受磨损但不承受破碎冲击；皮带输送机托辊属于输送部件，不承受破碎力；除尘风机叶轮与破碎腔无直接冲击关联。","tier":"进阶"},{"id":33,"type":"single","stem":"溢流型球磨机排矿粒度突然变粗、返砂量明显减少，在给矿量和矿石性质未变的情况下，最可能的原因是","options":["磨机给水量增大","分级机溢流堰降低","磨机临界转速提高","分级机主轴转速降低"],"answer":[3],"explanation":"知识点：磨矿分级闭路循环中返砂量与分级效率的关系。分级机主轴转速降低时，螺旋提升返砂能力下降，返砂量减少，同时合格粒级未能及时分出，导致溢流粒度变粗。给水量增大通常使溢流变细；溢流堰降低会使溢流变粗但返砂量一般增加；临界转速由设备结构决定，运行中不会改变。","tier":"挑战"},{"id":34,"type":"single","stem":"浮选机刮板刮出的泡沫层变薄、颜色变深且回收率下降，现场首先应检查的药剂添加环节是","options":["捕收剂添加量是否偏大","起泡剂添加量是否偏小","调整剂添加量是否偏大","活化剂添加量是否偏小"],"answer":[1],"explanation":"知识点：浮选泡沫状态与起泡剂用量的关系。起泡剂不足时泡沫脆、层薄、颜色变深，矿物来不及上浮，回收率下降。捕收剂偏大通常泡沫发达但选择性差；调整剂偏大主要影响抑制或活化效果而非泡沫层厚度；活化剂偏小影响的是目的矿物可浮性，不是泡沫层厚薄的直接原因。","tier":"挑战"},{"id":35,"type":"single","stem":"磁选机分选效果变差，精矿品位下降，检查发现磁滚筒表面附着大量矿泥，正确的处理方式是","options":["降低磁滚筒转速冲掉矿泥","增大给矿量把矿泥挤走","停机清洗磁滚筒表面","提高磁偏角加大磁力吸附"],"answer":[2],"explanation":"知识点：磁选机磁滚筒表面附着矿泥的影响与处理。矿泥附着会隔开矿粒与磁滚筒，降低分选选择性，必须停机清洗。降低转速不能去除已附着矿泥；增大给矿量会加重附着；提高磁偏角改变的是磁场分布角度，不能清除表面矿泥。","tier":"挑战"},{"id":36,"type":"single","stem":"现场取样测定磨矿产品细度时，正确的操作是","options":["在磨机排矿口接取瞬时样","在分级机溢流口截取全断面样","在返砂溜槽中部取少量样","在球磨机给矿皮带上取样"],"answer":[1],"explanation":"知识点：磨矿产品细度检测的取样代表性。分级机溢流是最终磨矿产品，需在溢流口全断面截取才有代表性。排矿口取的是磨机排矿，含大量未分级物料；返砂是返回到磨机的粗粒，不代表产品；给矿皮带取的是原矿，不是磨矿产品。","tier":"进阶"},{"id":37,"type":"single","stem":"浮选过程中发现精矿泡沫中脉石矿物含量升高，镜检发现连生体增多，在磨矿细度不变的条件下，最有效的调整措施是","options":["增加捕收剂用量","增加起泡剂用量","增加抑制剂用量","提高磨矿分级返砂量"],"answer":[2],"explanation":"知识点：浮选精矿品位下降时抑制剂的作用。连生体增多说明目的矿物与脉石未单体解离，但细度不变时提高抑制剂用量可抑制脉石上浮，改善精矿品位。增加捕收剂会同时捕收脉石；增加起泡剂只改变泡沫量不改变选择性；提高返砂量会改变磨矿负荷，不是针对脉石上浮的直接措施。","tier":"挑战"},{"id":38,"type":"single","stem":"某选矿厂处理含硫铁矿的铜矿石，浮选铜时加入石灰的主要作用是","options":["抑制黄铁矿并调节矿浆pH","活化黄铜矿并提高回收率","分散矿泥并降低药剂消耗","作为起泡剂改善泡沫结构"],"answer":[0],"explanation":"知识点：石灰在铜硫浮选中的作用。石灰提高矿浆pH并抑制黄铁矿，实现铜硫分离。石灰不是黄铜矿的活化剂；分散矿泥常用水玻璃；石灰没有起泡剂功能。","tier":"基础"},{"id":39,"type":"single","stem":"棒磨机与球磨机相比，其产品粒度特性最显著的区别是","options":["棒磨产品粒度更细更均匀","棒磨产品粒度较粗但更均匀","棒磨产品中过粉碎粒级更多","棒磨产品粒度分布更宽更离散"],"answer":[1],"explanation":"知识点：棒磨与球磨的磨矿产品粒度特性。棒磨以线接触磨矿，产品粒度较粗但均匀，过粉碎少。球磨以点接触为主，产品较细但过粉碎较多、分布较宽。因此细、过粉碎多、分布宽都是球磨特征。","tier":"基础"},{"id":40,"type":"single","stem":"浮选机槽内矿浆出现翻花、液面剧烈波动且泡沫层被破坏，最可能的原因是","options":["充气量过大","充气量过小","刮板转速过低","矿浆浓度过高"],"answer":[0],"explanation":"知识点：浮选机充气量对矿浆液面状态的影响。充气量过大时矿浆翻花、液面剧烈波动，泡沫层被破坏。充气量过小则液面平静、泡沫少；刮板转速低影响刮泡效率但不造成翻花；矿浆浓度高使矿浆黏稠，不会出现剧烈翻花。","tier":"基础"},{"id":41,"type":"single","stem":"在磁选流程中，对弱磁性矿物进行分选时通常采用的设备是","options":["永磁筒式磁选机","高梯度磁选机","电磁振动磁选机","离心选矿机"],"answer":[1],"explanation":"知识点：磁选设备按磁场强度的适用范围。弱磁性矿物需要高梯度磁选机提供高场强和高梯度才能有效分选。永磁筒式磁选机主要用于强磁性矿物；电磁振动磁选机不是按磁场强度分类的标准设备；离心选矿机属于重选设备。","tier":"基础"},{"id":42,"type":"single","stem":"某选矿厂球磨机运行中轴承温度持续升高，检查发现润滑油压力正常但油质发黑含杂质，正确的处置是","options":["继续运行并加大冷却水量","立即停机更换润滑油并清洗油路","降低磨机转速维持运行","提高给矿量缩短运行时间"],"answer":[1],"explanation":"知识点：球磨机轴承温度异常与润滑油质的关系。油质发黑含杂质说明润滑油已劣化并可能磨损轴承，必须停机换油并清洗油路。加大冷却水只能暂时降温，不能解决油质问题；降低转速和调整给矿量都不解决润滑劣化，继续运行会损坏轴承。","tier":"挑战"},{"id":43,"type":"single","stem":"颚式破碎机运行中突然出现排料口堵塞且飞轮转速明显下降，现场操作人员应首先采取的措施是","options":["立即切断给料并停机后清理堵塞","继续给料把堵塞物料挤出去","加大排料口尺寸让物料自行落下","向破碎腔内注水冲洗堵塞物料"],"answer":[0],"explanation":"知识点为颚式破碎机堵料处置。破碎腔堵塞时继续给料会加剧过载甚至损坏设备，注水对颚破堵塞无效且可能造成后续流程问题，先停机再清理是安全规程要求。","tier":"挑战"},{"id":44,"type":"single","stem":"球磨机磨矿产品粒度变粗、返砂量明显减少时，最可能的原因是","options":["给矿量突然增大","分级机溢流堰过高","磨矿浓度过低","钢球充填率过高"],"answer":[0],"explanation":"知识点为磨矿闭路中给矿量变化对产品粒度的影响。给矿量增大使物料在磨机内停留时间缩短，产品变粗且返砂减少；溢流堰过高会使返砂返回量增大，浓度过低和充填率过高通常使产品变细或返砂增多。","tier":"基础"},{"id":45,"type":"single","stem":"某选矿厂浮选铜硫矿时，优先浮铜后尾矿再选硫，尾矿选硫前通常需要加入的调整剂是","options":["硫酸铜","石灰","松醇油","硫化钠"],"answer":[0],"explanation":"知识点为优先浮选流程中尾矿再选硫的活化。铜被优先浮出后，黄铁矿常受石灰抑制，需用硫酸铜活化后再用黄药浮选；石灰是抑制剂，松醇油是起泡剂，硫化钠多用于硫化氧化矿。","tier":"进阶"},{"id":46,"type":"single","stem":"选矿厂磨矿分级闭路流程中，分级机返砂量突然增大且溢流变粗，最先应检查的环节是","options":["磨机给矿量和水量的配比","浮选药剂添加量","磁选机磁场强度","精矿脱水过滤机真空度"],"answer":[0],"explanation":"知识点为磨矿分级闭路的异常判断。返砂增大且溢流变粗通常由磨矿浓度、给矿量或水量失衡引起，应先查给矿量与水量的配比；浮选、磁选、脱水环节在分级之后，不影响返砂量。","tier":"挑战"},{"id":47,"type":"single","stem":"浮选机运行中泡沫层变薄、泡沫发脆且精矿品位下降，最可能的原因是","options":["起泡剂用量不足","捕收剂用量过多","矿浆pH值过高","充气量过小"],"answer":[0],"explanation":"知识点为浮选泡沫状态与药剂制度的关系。起泡剂不足时泡沫层薄、发脆、稳定性差，精矿品位下降；捕收剂过多通常泡沫量大且品位下降但泡沫不脆，pH过高和充气量小不会造成泡沫发脆。","tier":"进阶"},{"id":48,"type":"multi","stem":"某选矿厂处理含泥量高的氧化铜矿石，浮选时出现精矿品位低、药剂消耗大的问题，下列调整措施中合理的是","options":["添加水玻璃抑制脉石矿泥","采用分段加药方式控制药剂浓度","适当增加硫化钠用量硫化氧化铜矿物","提高浮选机充气量强化矿泥上浮","将矿浆浓度提高到70%以上改善矿化"],"answer":[0,1,2],"explanation":"知识点为高含泥氧化铜矿浮选调整。水玻璃可分散和抑制脉石矿泥，分段加药避免药剂被矿泥大量吸附，硫化钠可硫化氧化铜矿物再用黄药浮选；提高充气量会加剧矿泥夹带使品位更低，矿浆浓度过高则矿化变差、分选恶化。","tier":"进阶"},{"id":49,"type":"single","stem":"浮选作业中，矿浆pH值对药剂作用影响显著，当需要抑制石英等脉石矿物并浮选有色金属硫化矿时，通常将矿浆pH值调整到哪个范围最有利于提高精矿品位","options":["弱酸性至中性，约pH 5～7","弱碱性至中性，约pH 7～9","强碱性，约pH 10～12","强酸性，约pH 2～4"],"answer":[2],"explanation":"知识点是浮选矿浆pH调整对脉石抑制的作用。浮选硫化矿时常用石灰将矿浆调至强碱性（pH 10～12），使石英、硅酸盐等脉石表面亲水而被抑制，同时有利于黄药类捕收剂选择性吸附在硫化矿表面，故C正确。A弱酸性至中性对石英抑制弱，脉石易上浮降低精矿品位；B弱碱性抑制效果不足，精矿品位提升有限；D强酸性会破坏黄药稳定性并腐蚀设备，现场极少采用。","tier":"进阶"},{"id":50,"type":"multi","stem":"某铜硫选矿厂磨矿分级溢流突然变粗，浮选粗选泡沫明显变薄、铜回收率下降，现场检查给矿量、给水量和返砂量均正常，此时下列处置措施中合理的有","options":["检查分级机溢流堰是否磨损或堵塞","取样测定磨机排矿和溢流粒度组成","适当增加磨机给矿量以稳定循环负荷","检查磨机衬板磨损及钢球充填率是否偏低","立即将浮选药剂用量整体提高一倍"],"answer":[0,1,3],"explanation":"知识点是磨矿分级溢流跑粗的原因排查与处置。溢流变粗且给水、返砂正常时，应检查分级机溢流堰是否磨损或堵塞（A合理），并取样做粒度分析以确认跑粗程度（B合理）；衬板磨损或钢球充填率偏低会降低磨矿效果导致跑粗，需检查（D合理）。C增加给矿量会进一步加重磨机负荷、使产品更粗，方向错误；E盲目将药剂整体加倍不能解决粒度问题，还会造成药剂浪费和浮选选择性下降。","tier":"挑战"},{"id":51,"type":"single","stem":"颚式破碎机工作时突然出现推力板折断，现场检查发现肘板座内有异物卡入，正确的处置顺序是","options":["先停机断电挂牌，再清除异物并检查肘板与肘板座磨损情况","先清除异物让设备空转观察，确认无异常后再补挂停机牌","先更换新推力板，再清理肘板座并点动试车确认","先向调度汇报，再在运行状态下用工具拨出卡入异物"],"answer":[0],"explanation":"知识点：颚破推力板折断后的安全处置。正确项遵循先停机断电挂牌、再清障检查的原则，防止误启动和二次损坏。错误项一先清障后挂牌，设备可能被误启动；错误项二未清障就换板，新板会再次折断；错误项三运行时拨异物属危险作业，且未消除根源。"},{"id":52,"type":"single","stem":"球磨机排矿粒度突然变粗，同时返砂量明显减少，在给矿量和矿石性质未变的情况下，最应先检查的是","options":["分级机溢流堰高度是否被降低","磨机给水是否被误关小","磨机转速是否被调高","钢球充填率是否过高"],"answer":[1],"explanation":"知识点：磨矿分级闭路中排矿变粗与返砂减少的联合判断。给水减少使矿浆变稠、流速变慢，磨机内停留时间缩短且分级返砂下降，排矿变粗。溢流堰降低会增大溢流排出、返砂不一定减少；转速调高通常磨矿变细；充填率过高一般不至于突然使返砂骤减。"},{"id":53,"type":"single","stem":"浮选过程中发现精矿泡沫层变薄、颜色发暗、刮出量减少，同时尾矿品位上升，最可能的原因是","options":["捕收剂用量偏低或起泡剂失效","矿浆pH值突然升高","浮选机充气量过大","精矿刮板转速过快"],"answer":[0],"explanation":"知识点：浮选泡沫状态与药剂制度的对应关系。捕收剂不足或起泡剂失效使矿物疏水性下降、泡沫变薄发暗、精矿量减少且尾矿跑矿。pH升高通常影响特定矿物浮选但不会同时出现泡沫变薄发暗；充气量过大会使泡沫脆化但尾矿品位不一定上升；刮板过快只影响刮出量不改变泡沫性质。"},{"id":54,"type":"single","stem":"磁选机给矿浓度突然降低，在磁场强度和给矿量不变时，精矿品位和回收率的变化趋势通常是","options":["品位下降、回收率上升","品位上升、回收率下降","品位和回收率同时上升","品位和回收率同时下降"],"answer":[1],"explanation":"知识点：磁选给矿浓度对分选指标的影响。浓度降低使矿浆黏度下降、脉石夹带减少，精矿品位上升；但矿粒与磁介质碰撞几率降低，磁性矿粒流失增多，回收率下降。浓度升高才可能出现品位降回收升；同时升降与浓度单因素变化规律不符。"},{"id":55,"type":"single","stem":"在浮选厂中，使用石灰调节矿浆pH时，石灰乳添加点通常设在","options":["球磨机给矿口或分级机返砂处","浮选机精矿泡沫槽内","尾矿泵池出口管路上","精矿脱水浓密机给矿管上"],"answer":[0],"explanation":"知识点：浮选药剂添加点选择。石灰乳需在磨矿分级作业中加入，使pH在矿浆进入浮选前充分作用并抑制易浮脉石。加在精矿泡沫槽、尾矿泵池或浓密机给矿管均远离浮选作业，无法有效调节浮选pH。"},{"id":56,"type":"single","stem":"某选矿厂处理含泥量高的氧化矿，采用单一浮选回收率很低，现场最合理的下一步调整方向是","options":["先脱泥再浮选或采用泥砂分选流程","直接加大捕收剂用量强化浮选","提高浮选机转速延长浮选时间","降低磨矿细度使矿浆变粗"],"answer":[0],"explanation":"知识点：含泥氧化矿的选别工艺选择。矿泥会罩盖矿物表面、消耗药剂，先脱泥或泥砂分选可改善浮选环境。单纯加大捕收剂会被矿泥大量消耗且恶化选择性；提高转速延长时间不能解决矿泥干扰；降低细度使单体解离更差。"},{"id":57,"type":"single","stem":"重选摇床操作中，发现精矿带变窄且中矿带明显增宽，在冲程冲次不变时，最应先调整的是","options":["横向冲洗水量","给矿浓度","床面倾角","接矿槽位置"],"answer":[0],"explanation":"知识点：摇床横向水流对分带的影响。横向水量增大使矿粒沿横向搬运增强，精矿带变窄、中矿带增宽。给矿浓度主要影响处理量和分层；床面倾角改变整体流速分布但调整幅度大；接矿槽位置只改变截取产品不改变分带。"},{"id":58,"type":"single","stem":"棒磨机与球磨机相比，在选矿厂中棒磨机更常用于","options":["粗磨或第一段磨矿防止过粉碎","细磨至0.074mm以下","与水力旋流器组成细磨闭路","作为精矿再磨设备"],"answer":[0],"explanation":"知识点：棒磨机与球磨机的工艺差异。棒磨机以线接触破碎为主，产品粒度均匀、过粉碎少，适合粗磨或第一段磨矿。细磨、细磨闭路和精矿再磨一般用球磨机，因其研磨体为点接触更适合细粒磨矿。"},{"id":59,"type":"single","stem":"浮选机运行中，叶轮与定子间隙因磨损明显增大，最可能出现的现象是","options":["充气量下降、矿浆循环变差、浮选指标恶化","充气量增大、泡沫层变厚、精矿品位升高","矿浆循环增强、药剂分散更好、回收率提高","叶轮电流明显下降、设备振动减小"],"answer":[0],"explanation":"知识点：浮选机叶轮定子间隙的作用。间隙增大使泵送和吸气能力下降，矿浆循环变差、充气量降低，浮选指标恶化。间隙增大不会提高充气量和品位，也不会改善循环和药剂分散；电流和振动变化不是该磨损的主要特征。"},{"id":60,"type":"multi","stem":"某铜硫矿浮选流程中，铜硫分离困难，现场拟通过调整药剂制度改善分离效果，下列措施合理的是","options":["在铜硫分离作业加入石灰提高pH抑制黄铁矿","在混合浮选后加入硫化钠活化被抑制的铜矿物","在分离粗选前适当增加捕收剂用量强化铜矿物浮选","在分离作业前进行再磨使铜硫连生体解离","在分离作业中加大起泡剂用量提高泡沫层厚度"],"answer":[0,1,3],"explanation":"知识点：铜硫分离的药剂与工艺调整。加石灰提高pH可抑制黄铁矿，硫化钠可活化被抑制的铜矿物，再磨使连生体解离均有利于分离。分离前增加捕收剂会同时强化黄铁矿上浮，恶化分离；加大起泡剂只改变泡沫量，不解决铜硫选择性分离问题。"},{"id":61,"type":"single","stem":"球磨机排矿浓度突然变稀、返砂量明显减少，同时磨音变响，合理的调节方向是","options":["适当增加给矿量","适当减少给矿量","加大排矿补加水","降低分级机溢流堰高度"],"answer":[0],"explanation":"知识点：磨矿分级闭路操作调节。磨音变响、排矿变稀、返砂减少说明磨机内矿量偏少，应适当增加给矿量，所以正确。减少给矿量会进一步加剧空磨。加大排矿补加水会使浓度更稀。降低溢流堰高度会改变分级粒度，不解决磨机内矿量偏少的问题。"},{"id":62,"type":"single","stem":"磁选机分选效果变差，精矿品位下降，检查发现给矿中矿泥含量明显增多，较合理的处理措施是","options":["适当降低磁选机给矿浓度","提高磁选机滚筒转速","增大磁选机给矿粒度","减少磁选机冲洗水量"],"answer":[0],"explanation":"知识点：磁选给矿性质对分选的影响。矿泥多会机械夹杂降低品位，适当降低给矿浓度可减轻夹杂，所以正确。提高滚筒转速主要影响处理量和卸矿，不解决矿泥夹杂。增大给矿粒度与矿泥问题无关。减少冲洗水量会加重夹杂，使品位更低。"},{"id":63,"type":"single","stem":"浮选泡沫层变薄、泡沫发脆、精矿品位偏高但回收率下降，首先应检查的是","options":["起泡剂用量是否偏少","捕收剂用量是否偏多","矿浆温度是否偏低","浮选机叶轮转速是否偏高"],"answer":[0],"explanation":"知识点：浮选泡沫状态与药剂制度。泡沫薄而脆、回收率低通常与起泡剂不足有关，所以正确。捕收剂偏多一般使泡沫增多、上浮量增大，与现象不符。矿浆温度偏低影响药剂作用速度，但不是首选检查项。叶轮转速偏高会使泡沫破碎，但通常伴随充气过大，不是最直接原因。"},{"id":64,"type":"single","stem":"在闭路磨矿中，分级机返砂量突然增大且返砂粒度变粗，可能的原因是","options":["磨机给矿量突然增大","分级机溢流堰过高","磨机排矿浓度过稀","分级机螺旋提升机构停转"],"answer":[0],"explanation":"知识点：磨矿分级闭路返砂变化。给矿量突然增大时磨机内矿量增多，排矿变粗，分级返砂量增大且变粗，所以正确。溢流堰过高会使溢流变粗但返砂量不一定增大。排矿浓度过稀会使返砂量减少。螺旋提升机构停转会造成返砂沉积，不是返砂量增大且变粗的常见原因。"},{"id":65,"type":"single","stem":"浮选机运行中，矿浆液面突然下降且充气量不足，检查发现叶轮与定子间隙过大，正确的处置是","options":["停机调整叶轮与定子间隙","立即加大给矿量","提高浮选机转速上限","向矿浆中加入更多起泡剂"],"answer":[0],"explanation":"知识点：浮选机充气与叶轮定子间隙。间隙过大会降低吸浆和充气能力，应停机调整间隙，所以正确。加大给矿量会加重液面波动。提高转速上限可能加剧磨损且不能根治间隙问题。加起泡剂只改变泡沫性质，不解决充气不足。"},{"id":66,"type":"single","stem":"某选矿厂处理磁铁矿，一段磨矿产品中-0.074mm含量偏低，欲提高磨矿细度，在保持处理量不变时较合理的做法是","options":["适当提高磨机转速并调整分级机溢流堰","增大磨机给矿量并减少补加水","降低磨机转速并增大钢球直径","减少分级机返砂量并降低排矿浓度"],"answer":[0],"explanation":"知识点：磨矿细度调节。提高磨机转速可增加冲击研磨，配合调整溢流堰可控制分级粒度，所以正确。增大给矿量会降低磨矿细度。降低转速、增大球径会使产品变粗。减少返砂量、降低排矿浓度与提高细度无直接正向关系。"},{"id":67,"type":"single","stem":"浮选过程中发现精矿泡沫中脉石矿物明显增多，泡沫颜色变浅，应优先考虑调整","options":["抑制剂用量","捕收剂用量","起泡剂用量","浮选机充气量"],"answer":[0],"explanation":"知识点：浮选药剂调整与选择性。脉石上浮增多说明选择性变差，应优先增加抑制剂，所以正确。捕收剂用量增加会加重脉石上浮。起泡剂主要影响泡沫量。充气量影响泡沫层结构，不是提高选择性的首选。"},{"id":68,"type":"single","stem":"磁选作业中，磁选机精矿卸矿困难、磁滚筒表面粘附较多矿粒，较可能的原因是","options":["冲洗水压力不足","给矿浓度过高","磁选机转速过低","精矿品位过高"],"answer":[0],"explanation":"知识点：磁选机卸矿与冲洗水作用。冲洗水压力不足时精矿不易被冲下，粘附在滚筒表面，所以正确。给矿浓度过高影响分选效果，但卸矿困难主因是冲洗不足。转速过低会使矿粒停留时间长，但不直接造成粘附。精矿品位高与卸矿困难无直接关系。"},{"id":69,"type":"single","stem":"某选矿厂浮选铜硫矿石，现场发现铜精矿品位达标但硫精矿含铜偏高，检查流程发现铜粗选尾矿直接进入硫粗选，最合理的改进措施是","options":["增加铜扫选作业并返回粗选","提高硫粗选捕收剂用量","降低铜粗选pH值","增大铜粗选充气量"],"answer":[0],"explanation":"知识点：浮选流程结构与金属损失。铜粗选尾矿直接进硫粗选，未回收连生体铜，增加铜扫选并返回粗选可减少铜损失，所以正确。提高硫粗选捕收剂会多浮硫，不能降低硫精矿含铜。降低pH不利于铜硫分离。增大充气量只影响泡沫量，不解决流程结构问题。"},{"id":70,"type":"single","stem":"选矿厂中，颚式破碎机给矿时最应避免的操作是","options":["给矿粒度接近破碎机最大允许给矿粒度","沿给矿口全长均匀布料","将大块矿石从给矿口一侧集中投入","给矿前清除矿石中的金属杂物"],"answer":[2],"explanation":"颚式破碎机给矿要求沿给矿口全长均匀布料，避免单侧集中给矿，否则会造成齿板局部磨损和偏心受力。A项给矿粒度接近最大允许值是正常操作范围；B项均匀布料是正确做法；D项清除金属杂物是防止设备损坏的必要措施。"},{"id":71,"type":"single","stem":"球磨机磨矿作业中，返砂比指的是","options":["分级机返砂量与新给矿量之比","磨机排矿量与返砂量之比","新给矿量与磨机排矿量之比","分级机溢流量与返砂量之比"],"answer":[0],"explanation":"返砂比是闭路磨矿中分级机返砂量与新给矿量之比，反映磨矿回路负荷状态。B项排矿量与返砂量之比不是返砂比定义；C项新给矿量与排矿量之比接近回收率概念；D项溢流量与返砂量之比描述的是分级机分配关系。"},{"id":72,"type":"single","stem":"磁选机分选过程中，提高磁选机筒体转速对分选效果的影响是","options":["磁性矿粒所受离心力增大，可提高精矿品位但回收率可能下降","磁性矿粒所受离心力减小，精矿品位和回收率均提高","磁性矿粒所受离心力增大，精矿品位和回收率均提高","磁性矿粒所受离心力减小，可提高回收率但精矿品位可能下降"],"answer":[0],"explanation":"提高筒体转速使磁性矿粒所受离心力增大，较弱的磁性连生体容易被甩掉，精矿品位提高，但部分细粒磁性矿粒也可能被甩入尾矿，回收率可能下降。B、D项离心力变化方向判断错误；C项品位和回收率同时提高不符合分选规律。"},{"id":73,"type":"single","stem":"某选矿厂浮选作业中，发现精矿品位突然下降、泡沫层变薄且泡沫发脆，最先应检查的操作环节是","options":["磨矿细度是否突然变粗","浮选机叶轮转速是否过高","精矿输送泵是否堵塞","尾矿闸门开度是否过大"],"answer":[0],"explanation":"精矿品位下降、泡沫层变薄发脆，常见原因是磨矿细度变粗导致连生体增多，应优先检查磨矿分级作业。B项叶轮转速过高通常使泡沫层变厚而非变薄；C项精矿泵堵塞影响输送不影响浮选泡沫；D项尾矿闸门影响液位，与泡沫发脆关系不直接。"},{"id":74,"type":"single","stem":"圆锥破碎机采用挤满给矿方式运行时，正确的操作要求是","options":["给矿量保持在破碎腔容积的百分之百以上","给矿量使破碎腔始终充满矿石并保持料位稳定","给矿量控制在破碎腔容积的三分之一以下","给矿量随破碎腔料位高低间断性加入"],"answer":[1],"explanation":"挤满给矿要求破碎腔始终充满矿石并保持稳定料位，利用层压破碎原理提高破碎效率和产品粒度均匀性。A项超过百分之百会过载闷车；C项三分之一以下属于非挤满给矿；D项间断给矿无法形成稳定料层。"},{"id":75,"type":"single","stem":"浮选药剂中，石灰在铜硫分离作业中主要起的作用是","options":["作为起泡剂增加泡沫稳定性","作为抑制剂抑制黄铁矿上浮","作为捕收剂增强黄铜矿疏水性","作为分散剂防止矿泥团聚"],"answer":[1],"explanation":"石灰在铜硫分离中作为pH调整剂兼抑制剂，提高矿浆pH后抑制黄铁矿上浮，实现铜硫分离。A项起泡剂通常是松醇油等；C项捕收剂是黄药或黑药；D项分散剂是水玻璃等。"},{"id":76,"type":"single","stem":"螺旋分级机溢流中跑粗现象突然加重，与下列哪个原因关系最直接","options":["分级机螺旋叶片磨损严重","磨机给矿量突然减小","分级机溢流堰高度突然降低","磨机排矿浓度突然变稀"],"answer":[3],"explanation":"磨机排矿浓度突然变稀时矿浆黏度降低，粗颗粒沉降速度加快但随上升水流进入溢流的几率增大，导致跑粗加重。A项叶片磨损影响返砂输送不影响溢流粒度；B项给矿量减小通常溢流变细；C项溢流堰降低使溢流面积变化，不是跑粗的直接原因。"},{"id":77,"type":"single","stem":"在选矿厂中，对磁铁矿进行干式磁选预选的主要目的是","options":["将矿石磨细至单体解离后分选","在粗粒条件下提前抛除部分脉石","对精矿进行脱水处理","将矿石按粒度大小进行分级"],"answer":[1],"explanation":"干式磁选预选用于粗粒条件下提前抛除脉石，减少后续磨矿量，降低能耗。A项磨细至单体解离是磨矿作业目标；C项脱水是精矿处理环节；D项分级是分级作业功能。"},{"id":78,"type":"single","stem":"浮选机充气量突然增大而其他条件不变时，对浮选过程的直接影响是","options":["泡沫层变薄，精矿品位提高","泡沫层增厚，精矿品位可能下降","矿浆pH值显著升高","捕收剂用量自动减少"],"answer":[1],"explanation":"充气量增大使泡沫层增厚、泡沫携带脉石增多，精矿品位可能下降。A项泡沫层变薄与充气量增大相反；C项充气量不影响矿浆pH；D项捕收剂用量由药剂制度决定，不会自动减少。"},{"id":79,"type":"single","stem":"某选矿厂球磨机出现“胀肚”现象，筒体声音沉闷、排矿量骤减，正确的首要处置是","options":["立即增加给矿量以提高磨矿浓度","立即停止给矿并适当加大补加水","立即提高分级机转速加快返砂","立即加入钢球补充磨矿介质"],"answer":[1],"explanation":"胀肚时磨机内矿量过多，应停止给矿并适当加大补加水，使矿浆顺利排出，待恢复正常后再逐步恢复给矿。A项增加给矿量会加重胀肚；C项提高分级机转速不能解决磨机内积矿；D项加钢球会进一步增加磨机负荷。"},{"id":80,"type":"single","stem":"颚式破碎机运行中突然出现排矿口明显变大、动颚摆动无力，最可能的原因是","options":["推力板折断","偏心轴转速过高","飞轮配重块脱落","给矿粒度偏小"],"answer":[0],"explanation":"推力板是颚破的保险件，折断后动颚失去支撑，排矿口变大且摆动减弱。偏心轴转速过高只会加剧振动，不会使排矿口变大；飞轮配重块脱落会引发剧烈振动但肘板仍支撑动颚；给矿粒度偏小影响的是通过能力而非排矿口尺寸。"},{"id":81,"type":"single","stem":"球磨机排矿浓度突然变稀、返砂量明显增大，通常说明","options":["给矿量过大","给矿量过小","磨矿浓度过高","分级机溢流堰过低"],"answer":[1],"explanation":"给矿量减小时，磨机内矿浆水量相对增多，排矿变稀，同时磨矿产品变粗使返砂量增大。给矿量过大则排矿变浓、返砂可能减少；磨矿浓度过高与排矿变稀矛盾；溢流堰过低影响溢流粒度而非返砂与排矿浓度同步变化。"},{"id":82,"type":"single","stem":"浮选过程中发现精矿品位下降、泡沫层变薄且发脆，最有效的调整措施是","options":["增加捕收剂用量","减少起泡剂用量","降低矿浆浓度","提高浮选机转速"],"answer":[0],"explanation":"泡沫变薄发脆、品位下降多因捕收剂不足导致矿物表面疏水性不够，适量增加捕收剂可恢复。减少起泡剂会进一步削弱泡沫层；降低矿浆浓度对泡沫性质改善有限；提高转速主要影响充气与搅拌，不能解决捕收不足问题。"},{"id":83,"type":"single","stem":"磁选机给矿中混入大量非磁性粗颗粒后，最先出现的异常现象是","options":["精矿品位升高","尾矿品位升高","精矿品位降低","磁滚筒转速下降"],"answer":[2],"explanation":"非磁性粗颗粒会机械夹带进入精矿，使精矿品位降低。非磁性物不会使精矿品位升高；尾矿品位变化不是最先表现；磁滚筒转速由传动决定，不会因给矿混入粗粒而下降。"},{"id":84,"type":"single","stem":"水力旋流器溢流中出现明显粗颗粒，可能的原因是","options":["沉砂口磨损扩大","给矿压力偏低","溢流管磨损变短","给矿浓度偏低"],"answer":[0],"explanation":"沉砂口磨损扩大使底流排量增大、内部上升流增强，粗粒易被带入溢流。给矿压力偏低使分级效果变差、溢流变粗，但主因是压力不足而非磨损；溢流管磨损变短会改变空气柱，一般使溢流变粗但需结合压力判断；给矿浓度偏低使分级粒度变细而非变粗。"},{"id":85,"type":"single","stem":"摇床选别中矿带明显变宽、精矿带变窄，且精矿品位下降，应优先调整","options":["增大冲程","减小横向坡度","增大给矿量","减小冲洗水量"],"answer":[1],"explanation":"矿带变宽、精矿带变窄说明横向水流过强或坡度偏大，减小横向坡度可使矿带收窄、精矿带变宽并提高品位。增大冲程主要影响纵向分层；增大给矿量会加重分选负担；减小冲洗水量会改变矿带形态但坡度是首选调整量。"},{"id":86,"type":"single","stem":"浮选机叶轮盖板磨损后，浮选过程最典型的表现是","options":["充气量增大","泡沫层变厚","矿浆循环量减少","精矿品位升高"],"answer":[2],"explanation":"叶轮盖板磨损后泵送与循环能力下降，矿浆循环量减少，浮选效果变差。充气量通常减少而非增大；泡沫层变薄而非变厚；精矿品位一般下降而非升高。"},{"id":87,"type":"single","stem":"一段磨矿分级闭路中，分级机返砂量突然大幅减少而溢流变粗，较可能的原因是","options":["磨机给矿量减少","磨机排矿口堵塞","分级机溢流堰升高","磨机转速降低"],"answer":[1],"explanation":"磨机排矿口堵塞使矿浆不能正常排出，进入分级机的物料减少，返砂量骤减，同时合格粒级减少使溢流变粗。给矿量减少会使返砂减少但溢流一般变细；溢流堰升高使溢流变细；转速降低使产品变粗但返砂通常增加。"},{"id":88,"type":"single","stem":"某铜矿浮选流程中，扫选精矿返回粗选，若扫选作业回收率突然下降，首先应检查","options":["粗选药剂用量","扫选充气量","精矿过滤水分","尾矿泵扬程"],"answer":[1],"explanation":"扫选回收率下降多因扫选作业充气不足或搅拌不良，应首先检查充气量。粗选药剂用量主要影响粗选指标；精矿过滤水分与扫选回收无关；尾矿泵扬程影响输送而非浮选回收。"},{"id":89,"type":"single","stem":"强磁选机分选弱磁性矿石时，给矿粒度过粗会导致","options":["磁性矿粒回收率下降","非磁性矿粒回收率上升","介质盒堵塞减轻","精矿品位提高"],"answer":[0],"explanation":"粒度过粗时磁性矿粒所受磁力不足以克服重力与流体阻力，回收率下降。非磁性矿粒不会因粒度粗而回收率上升；介质盒堵塞会加重而非减轻；精矿品位一般下降而非提高。"},{"id":90,"type":"single","stem":"浮选药剂添加顺序中，一般应先加","options":["捕收剂","起泡剂","调整剂","絮凝剂"],"answer":[2],"explanation":"调整剂用于调节矿浆pH和抑制/活化矿物表面，应优先加入以创造适宜浮选环境。捕收剂和起泡剂通常在调整剂之后加入；絮凝剂用于浓缩脱水作业，不参与浮选药剂顺序。"},{"id":91,"type":"multi","stem":"关于磨矿分级作业操作，下列做法正确的有","options":["根据返砂量及时调整给矿量","定期检查分级机叶片磨损情况","磨矿浓度过高时直接加大量水快速稀释","溢流粒度变粗时立即提高分级机转速","每班记录磨机电流和排矿浓度"],"answer":[0,1,4],"explanation":"调整给矿量、检查叶片磨损、记录电流与浓度都是磨矿分级正常操作内容。磨矿浓度过高应缓慢加水并观察，直接大量加水会造成浓度波动；溢流变粗应先查给矿量与分级机状况，直接提高转速不是规范处置。"},{"id":92,"type":"single","stem":"选矿厂颚式破碎机运行中突然出现排矿口堵塞，正确的第一处置动作是","options":["立即停机后清理堵塞物料","继续给料把堵塞物料挤下去","打开排矿口调大后再清理","加大给水量冲走堵塞物料"],"answer":[0],"explanation":"知识点：破碎机堵塞处置。颚破堵料时必须先停机切断动力，再清理，防止清理时机器突然启动或物料崩出伤人；继续给料会加剧堵塞甚至撑坏设备；先调排矿口而不停机仍处危险状态；颚破一般不靠加水冲堵。"},{"id":93,"type":"single","stem":"球磨机磨矿产品粒度突然变粗，给矿量和给水量均未改变，最可能的原因是","options":["磨机转速略微下降","分级机返砂量增大","钢球磨损后充填率下降","给矿粒度变细"],"answer":[2],"explanation":"知识点：磨矿粒度影响因素。钢球磨损使充填率下降、研磨能力减弱，产品会变粗；转速下降通常使磨矿变差但题目已限定给矿给水不变且转速未提及；返砂量增大往往与分级返砂有关，不是产品变粗的直接原因；给矿变细应使产品变细。"},{"id":94,"type":"single","stem":"浮选过程中发现精矿泡沫发黏、品位下降，同时回收率也降低，现场操作上较合理的调整是","options":["增加捕收剂用量强化回收","减少起泡剂用量改善泡沫","提高浮选机转速加强搅拌","加大给矿量提高处理能力"],"answer":[1],"explanation":"知识点：浮选泡沫状态判断。泡沫发黏多因起泡剂过量或药剂失调，减少起泡剂可改善泡沫脆性、提高选择性；增加捕收剂会加重夹带使品位更低；提高转速会加剧泡沫夹带；加大给矿量只会恶化分选。"},{"id":95,"type":"single","stem":"磁选机分选效果变差，给矿浓度和磁场强度正常，检查发现磁系表面粘附大量矿泥，正确的处理方式是","options":["停机清洗磁系表面矿泥","提高磁场强度继续分选","加大冲洗水量暂时维持","降低给矿浓度继续运行"],"answer":[0],"explanation":"知识点：磁选机维护。磁系粘泥会阻碍磁性颗粒吸附、降低分选指标，应停机清洗；提高磁场强度不能解决粘泥问题；加大冲洗水量和降低浓度只是暂时缓解，不能恢复磁系清洁。"},{"id":96,"type":"single","stem":"浮选作业中矿浆pH值对药剂作用影响很大，浮选硫化矿常用石灰调节pH，其主要作用是","options":["提高矿浆温度促进反应","抑制黄铁矿等脉石矿物","增加矿浆黏度稳定泡沫","降低捕收剂消耗量"],"answer":[1],"explanation":"知识点：浮选pH调整。石灰调高pH可抑制黄铁矿等硫化脉石矿物上浮，提高精矿品位；石灰不主要起升温、增黏或直接降药耗作用，那些是错误关联。"},{"id":97,"type":"single","stem":"某选矿厂磨矿分级回路中返砂量明显增大，分级溢流变粗，较合理的操作调整是","options":["适当减少磨机给矿量","开大分级机溢流堰","提高磨机转速","减少磨机给水量"],"answer":[0],"explanation":"知识点：磨矿分级回路调节。返砂量增大且溢流变粗说明磨矿产品未及时磨细或分级效率下降，适当减少给矿量可让磨机有更多时间研磨，使产品变细；开大溢流堰会改变分级粒度但不解决磨矿不足；提高转速未必有效且可能加剧过磨；减少给水会使矿浆变稠，分级更差。"},{"id":98,"type":"single","stem":"浮选机运行中泡沫层突然消失、矿化泡沫减少，现场首先应检查的是","options":["捕收剂和起泡剂添加是否中断","浮选机叶轮是否磨损","矿浆pH值是否偏高","精矿管道是否堵塞"],"answer":[0],"explanation":"知识点：浮选泡沫异常判断。泡沫突然消失首先考虑药剂添加中断，尤其是起泡剂或捕收剂；叶轮磨损是渐进影响；pH偏高通常不会使泡沫瞬间消失；精矿管道堵塞影响排出而非泡沫生成。"},{"id":99,"type":"single","stem":"选矿厂棒磨机与球磨机相比，棒磨机在产品粒度特性上的典型特点是","options":["产品粒度更细更均匀","产品粒度较粗但较均匀","产品过粉碎较严重","产品粒度分布更宽"],"answer":[1],"explanation":"知识点：磨矿设备特性。棒磨机以线接触研磨为主，产品粒度较粗但均匀，过粉碎少；球磨机产品较细且分布宽，过粉碎较多。选项A、C、D均与棒磨机实际特性相反或混淆。"},{"id":100,"type":"single","stem":"某选矿厂磁选作业中，磁性产品品位偏高但回收率偏低，较合理的调整方向是","options":["降低磁选机磁场强度","提高给矿浓度","减小磁选机给矿量","增加磁选机冲洗水量"],"answer":[2],"explanation":"知识点：磁选指标调节。回收率偏低说明部分磁性矿物未回收，减小给矿量可延长分选时间、提高回收率；降低磁场强度会更降低回收率；提高给矿浓度和增加冲洗水量可能使磁性物损失更大或影响分选，不是针对性措施。"},{"id":101,"type":"single","stem":"选矿厂破碎车间采用三段一闭路流程，其中检查筛分的返回物料应返回","options":["粗碎作业","中碎作业","细碎作业","磨矿作业"],"answer":[2],"explanation":"知识点：破碎流程结构。三段一闭路中检查筛分设在细碎之后，筛上不合格产品返回细碎作业再破；返回粗碎或中碎会打乱流程负荷，返回磨矿则失去闭路意义。"},{"id":102,"type":"single","stem":"颚式破碎机给料时，给料块最大边长一般不应超过给料口宽度的多少","options":["0.85","0.75","0.65","0.55"],"answer":[0],"explanation":"知识点：颚破给料粒度控制。给料块最大边长通常不超过给料口宽度的0.85，过大易卡料、降低生产能力。0.75、0.65、0.55均偏保守，会造成破碎能力未充分利用，属于把安全余量放得过大的做法。"},{"id":103,"type":"single","stem":"圆锥破碎机采用挤满给料时，给料应分布在破碎腔的哪个位置","options":["沿给料口一侧集中落下","均匀布满破碎腔四周","偏向动锥一侧落下","偏向定锥一侧落下"],"answer":[1],"explanation":"知识点：圆锥破挤满给料操作。挤满给料要求矿石均匀布满破碎腔四周，使动锥受力均衡、层压破碎效果好。沿一侧集中落下会造成偏载、衬板局部磨损；偏向动锥或定锥一侧同样导致受力不均，是现场常见但错误的给料方式。"},{"id":104,"type":"single","stem":"螺旋分级机返砂量突然增大而溢流粒度变粗，应优先检查的是","options":["分级机螺旋转速","磨机给矿水量","分级机溢流堰高度","磨机衬板磨损情况"],"answer":[2],"explanation":"知识点：分级机溢流粒度调节。溢流堰高度决定分级区面积，堰低则溢流粗、返砂多，应优先检查溢流堰。螺旋转速影响返砂输送，不是粒度变粗的主因；给矿水量属于磨机操作；衬板磨损影响磨矿效率但不直接决定分级溢流粗细。"},{"id":105,"type":"single","stem":"硫化矿浮选中加入石灰的主要作用是","options":["提高矿浆温度","抑制黄铁矿并调节pH","增加矿浆黏度","促进气泡生成"],"answer":[1],"explanation":"知识点：浮选调整剂作用。石灰常用于抑制黄铁矿并提高矿浆pH。提高矿浆温度靠加温措施；增加矿浆黏度不是加石灰目的，反而可能恶化浮选；促进气泡生成靠起泡剂，与石灰无关。"},{"id":106,"type":"single","stem":"磁选机分选弱磁性矿石时，提高磁场强度对精矿品位和回收率的影响通常是","options":["品位提高回收率提高","品位降低回收率提高","品位提高回收率降低","品位降低回收率降低"],"answer":[1],"explanation":"知识点：磁选磁场强度与分选指标。提高磁场强度使更多连生体进入精矿，回收率升高但品位下降。品位与回收率同时提高不符合磁选规律；品位提高回收率降低通常是降低场强或加强精选的结果；两者同时降低则与提高场强的方向相反。"},{"id":107,"type":"single","stem":"浮选泡沫层变薄、气泡变大且易破裂，最可能缺少的药剂是","options":["捕收剂","起泡剂","抑制剂","活化剂"],"answer":[1],"explanation":"知识点：起泡剂作用与泡沫状态判断。起泡剂维持泡沫稳定和适宜大小，缺少时泡沫层薄、气泡大易破。捕收剂影响矿物疏水性，不直接决定泡沫稳定性；抑制剂抑制特定矿物；活化剂活化被抑制矿物，均不主要影响泡沫层厚度。"},{"id":108,"type":"single","stem":"一段磨矿与分级构成闭路时，分级机返砂返回哪里","options":["返回磨机再磨","进入浮选作业","进入浓缩机","排入尾矿"],"answer":[0],"explanation":"知识点：磨矿分级闭路流程。闭路中分级返砂为不合格粒级，应返回磨机再磨。进入浮选会使粗粒影响分选指标；进入浓缩机或排入尾矿则造成有用矿物损失，均不符合闭路设计目的。"},{"id":109,"type":"single","stem":"浮选流程中粗选精矿进入精选、精选尾矿返回粗选，这种返回方式称为","options":["开路流程","中矿返回流程","闭路流程","分支流程"],"answer":[1],"explanation":"知识点：浮选流程结构。精选尾矿作为中矿返回粗选属于中矿返回流程。开路流程无返回；闭路流程通常指磨矿分级闭路或精尾返回形成循环但不特指中矿返回；分支流程是将矿浆分流，与中矿返回概念不同。"},{"id":110,"type":"multi","stem":"选矿厂球磨机操作中，以下哪些做法有助于降低磨矿能耗并保持合格粒度","options":["保持适宜的磨矿浓度","采用闭路磨矿及时分出合格粒级","适当提高球磨机充填率至合理范围","给矿粒度尽量粗以增加处理量","磨机转速超过临界转速运行"],"answer":[0,1,2],"explanation":"知识点：磨矿节能操作。适宜浓度保证矿浆流动性，闭路及时分出合格粒级避免过磨，合理充填率提高研磨效率，均有助于节能保质。给矿过粗会降低处理量并增加能耗，不是节能做法；超过临界转速会使钢球离心贴壁失去研磨作用，属于错误操作。"},{"id":111,"type":"single","stem":"颚式破碎机给料时，物料块度超过给料口宽度的多少倍容易造成堵矿，应先用大锤或液压锤处理","options":["0.85倍","1.15倍","1.50倍","2.00倍"],"answer":[0],"explanation":"知识点：颚式破碎机给料块度一般不超过给料口宽度的0.85倍。给料口宽度是破碎机的重要参数，超过0.85倍的大块容易卡在给料口造成堵矿或设备过载，需预先破碎处理。1.15倍、1.50倍、2.00倍均超出安全给料上限，会导致堵矿或设备损坏。"},{"id":112,"type":"single","stem":"球磨机排矿浓度突然升高、溢流变粗，同时磨音变沉闷，最可能的原因是","options":["给矿量过大","给水量过大","钢球充填率过低","分级机返砂量过小"],"answer":[0],"explanation":"知识点：磨矿浓度、磨音与给矿量的关系。给矿量过大时，磨机内矿浆浓度升高、磨音沉闷、排矿变粗，是典型的过负荷征兆。给水量过大则浓度降低、磨音清脆、溢流变细；钢球充填率过低磨音也会变闷但溢流不会突然变粗；返砂量过小会使磨机内浓度偏低而非升高。"},{"id":113,"type":"single","stem":"浮选作业中，矿浆pH值对捕收剂效果影响显著，浮选硫化铜矿时常用石灰调节pH值至","options":["5~6","7~8","9~11","12~13"],"answer":[2],"explanation":"知识点：硫化铜矿浮选pH范围。硫化铜矿浮选常用石灰将pH调至9~11，以抑制黄铁矿、稳定泡沫并提高铜回收率。pH 5~6偏酸性不利于黄药类捕收剂作用；pH 7~8抑制黄铁矿效果不足；pH 12~13过高会抑制铜矿物本身并增加石灰消耗。"},{"id":114,"type":"single","stem":"磁选机分选过程中，给矿粒度对分选效果影响很大，对弱磁性矿物进行磁选时，给矿粒度一般要求","options":["小于0.2mm","0.5~2mm","2~5mm","5~10mm"],"answer":[0],"explanation":"知识点：弱磁性矿物磁选粒度要求。弱磁性矿物比磁化系数小，需要较细的粒度才能使磁性颗粒与脉石充分解离并被磁场捕获，一般要求小于0.2mm。0.5~2mm、2~5mm、5~10mm粒度过粗，连生体多、磁力不足以克服重力与水流阻力，分选效果差。"},{"id":115,"type":"single","stem":"浮选机充气量不足、泡沫发死，现场操作人员首先应检查的是","options":["叶轮与定子间隙是否过大","精矿品位是否偏高","尾矿闸门是否关严","药剂添加量是否偏少"],"answer":[0],"explanation":"知识点：浮选机充气不良的故障排查。充气量不足、泡沫发死最常见原因是叶轮与定子间隙磨损过大，导致吸气能力下降，应首先检查该间隙。精矿品位偏高是结果不是原因；尾矿闸门与充气无直接关系；药剂偏少影响泡沫性质但不会导致充气量不足。"},{"id":116,"type":"single","stem":"一段闭路磨矿中，螺旋分级机返砂量突然增大，同时磨机排矿粒度变粗，正确的调节方向是","options":["适当减少给矿量并增加给水量","适当增加给矿量并减少给水量","保持给矿量不变只减少给水量","停磨检查分级机螺旋叶片"],"answer":[0],"explanation":"知识点：闭路磨矿返砂量与给矿、给水的调节。返砂量增大且排矿变粗说明磨机内物料过多、浓度偏高，应减少给矿量并适当增加给水量以降低浓度、改善磨矿效果。增加给矿量会加剧过负荷；只减给水会进一步升高浓度；返砂增大未必是螺旋叶片故障，先调节操作参数更合理。"},{"id":117,"type":"single","stem":"浮选过程中发现精矿品位下降、回收率也下降，镜检发现脉石矿物被大量夹带上浮，最可能的原因是","options":["起泡剂用量过大","捕收剂用量不足","抑制剂用量过大","矿浆温度过低"],"answer":[0],"explanation":"知识点：起泡剂用量对浮选选择性的影响。起泡剂用量过大时泡沫过于稳定、黏度增大，脉石易被机械夹带上浮，导致精矿品位和回收率同时下降。捕收剂不足主要影响回收率；抑制剂过量会抑制目的矿物；矿浆温度过低影响药剂作用速度但不直接造成脉石夹带。"},{"id":118,"type":"single","stem":"重选摇床操作中，床面横向坡度增大时，为保证分选效果，应相应","options":["增大冲程或增大冲次","减小冲程或减小冲次","保持冲程冲次不变只增大给矿量","增大给矿浓度并减小给水量"],"answer":[0],"explanation":"知识点：摇床坡度与冲程冲次的配合。横向坡度增大时矿粒沿横向运动加快，需要增大冲程或冲次以增强纵向松散和搬运能力，保持分带清晰。减小冲程冲次会使矿粒纵向移动不足、分带变差；只增大给矿量会破坏床层松散；增大浓度减小给水会恶化分层。"},{"id":119,"type":"single","stem":"选矿厂尾矿库回水利用时，回水中残留浮选药剂对浮选作业的主要影响是","options":["影响药剂制度和浮选指标","提高精矿品位和回收率","降低磨矿机处理能力","增大磁选机磁场强度"],"answer":[0],"explanation":"知识点：回水对浮选的影响。尾矿库回水中含有残留捕收剂、起泡剂等，返回浮选会改变矿浆中药剂浓度和泡沫性质，干扰正常药剂制度，影响浮选指标。回水一般不会提高精矿指标；对磨矿处理能力影响很小；与磁选机磁场强度无关。"},{"id":120,"type":"single","stem":"某选矿厂处理磁铁矿，磁选精矿品位偏低，检查发现磁选机滚筒表面矿浆层过厚，正确的处置是","options":["适当减小给矿量并调整卸矿水量","增大给矿量提高处理能力","关小卸矿水使精矿更干","降低磁选机滚筒转速至最低"],"answer":[0],"explanation":"知识点：磁选机矿浆层厚度与分选效果。滚筒表面矿浆层过厚会夹带脉石，降低精矿品位，应适当减小给矿量并调整卸矿水量使矿层变薄、冲洗充分。增大给矿量会加厚矿层；关小卸矿水会使精矿夹带更多脉石；滚筒转速过低会降低处理能力和分选效率。"},{"id":121,"type":"single","stem":"破碎流程中，圆锥破碎机出现过铁或过铁后主轴突然上升、排矿口变大的现象，正确的处置是","options":["立即停机检查并清理破碎腔","继续给矿观察排矿口变化","加大给矿量压住主轴上升","关小排矿口继续生产"],"answer":[0],"explanation":"知识点：圆锥破碎机过铁后的处置。过铁会使主轴突然上升、排矿口增大，属于异常工况，必须立即停机检查破碎腔和主轴，清理异物并确认设备完好后再开机。继续给矿或加大给矿量会扩大设备损伤；关小排矿口不能消除过铁造成的隐患。"},{"id":122,"type":"single","stem":"选矿厂破碎作业中，颚式破碎机给矿块度超过给矿口尺寸的多少倍时，最容易发生卡矿或噎铁","options":["0.5倍","0.85倍","1.2倍","1.5倍"],"answer":[1],"explanation":"知识点：颚式破碎机给矿最大块度一般不超过给矿口宽度的0.85倍。正确项0.85倍符合设备给矿条件；0.5倍偏小，虽不卡矿但会降低处理量，不是卡矿主因；1.2倍和1.5倍均超过给矿口允许范围，但通常已属于明显堵矿工况，本题问最容易卡矿的临界值，0.85倍最接近实际操作上限。"},{"id":123,"type":"single","stem":"球磨机排矿口出现大量粗粒级矿物返砂，且分级机溢流粒度明显变粗，优先检查的工艺参数是","options":["磨矿浓度是否过高","分级机溢流堰高度是否被抬高","球磨机给矿量是否突然减小","磨机转速是否超过临界转速"],"answer":[1],"explanation":"知识点：分级机溢流堰高度直接影响溢流粒度。正确项溢流堰被抬高会使溢流变粗、返砂粗粒增多；磨矿浓度过高通常使矿浆黏度增大、溢流变细；给矿量减小一般使磨矿更细；磨机转速超过临界转速属于离心状态，实际运行中通常不会作为调节手段且现象不符。"},{"id":124,"type":"single","stem":"浮选作业中，矿浆pH值突然升高导致黄药捕收能力下降，最可能的原因是","options":["石灰添加量过大","起泡剂用量不足","浮选机充气量过小","精矿刮出速度过快"],"answer":[0],"explanation":"知识点：石灰是常用pH调整剂，过量会使矿浆pH升高并抑制黄药捕收。正确项石灰添加量过大符合现象；起泡剂不足主要影响泡沫量和稳定性；充气量过小影响浮选动力学而非pH；精矿刮出速度属于后续操作，不会改变矿浆pH。"},{"id":125,"type":"single","stem":"磁选机分选过程中，精矿品位下降且尾矿磁性铁含量升高，首先应调整的操作是","options":["增大磁选机给矿量","减小磁选机滚筒转速","降低磁选机磁场强度","增大磁选机冲洗水量"],"answer":[1],"explanation":"知识点：磁选滚筒转速影响物料在磁场区的停留时间。正确项减小转速可延长分选时间、提高磁性铁回收；增大给矿量会加重分选负荷使指标更差；降低磁场强度会减弱磁性铁吸附，尾矿磁性铁更高；增大冲洗水主要影响夹杂，不能解决磁性铁流失。"},{"id":126,"type":"single","stem":"某选矿厂一段磨矿分级作业中，螺旋分级机返砂量突然增大且返砂中细粒增多，最可能的原因是","options":["磨机给矿粒度变粗","分级机螺旋叶片磨损严重","磨机排矿浓度过低","分级机溢流堰被降低"],"answer":[1],"explanation":"知识点：螺旋分级机叶片磨损会降低返砂提升能力，使细粒不能有效返回磨机而混入返砂。正确项叶片磨损符合返砂量增大且细粒增多；给矿粒度变粗主要使返砂量增大但细粒比例不一定升高；排矿浓度过低会使矿浆稀释、溢流变粗；溢流堰降低会使溢流变细，与现象相反。"},{"id":127,"type":"single","stem":"浮选流程中，粗选精矿再磨后进入精选作业，若再磨细度不足，对精选作业最直接的影响是","options":["精矿品位难以提高","精矿产率明显下降","浮选泡沫变脆易破","捕收剂用量显著减少"],"answer":[0],"explanation":"知识点：粗精矿再磨是为了使有用矿物与脉石单体解离，再磨细度不足则连生体多，精选时品位难以提高。正确项精矿品位难以提高符合实际；精矿产率通常不会因此明显下降；泡沫变脆多与起泡剂或pH有关；捕收剂用量不会因再磨细度不足而显著减少。"},{"id":128,"type":"single","stem":"选矿厂使用水力旋流器进行分级时，旋流器溢流变粗、底流夹细增多，最可能的原因是","options":["旋流器给矿压力升高","旋流器沉砂口磨损扩大","旋流器给矿浓度降低","旋流器溢流管直径减小"],"answer":[1],"explanation":"知识点：沉砂口磨损扩大会使底流流量增大、底流夹细增多，同时溢流变粗。正确项沉砂口磨损扩大符合现象；给矿压力升高通常使分级更细；给矿浓度降低会使溢流变细；溢流管直径减小会使溢流变细、底流夹细减少。"},{"id":129,"type":"single","stem":"某选矿厂浮选铜硫矿石时，发现铜精矿中硫含量超标，优先采取的措施是","options":["增加石灰用量抑制黄铁矿","增加黄药用量强化铜矿物浮选","提高浮选机充气量","降低浮选矿浆温度"],"answer":[0],"explanation":"知识点：铜硫分离常用石灰抑制黄铁矿。正确项增加石灰用量可提高矿浆pH并抑制黄铁矿上浮；增加黄药会同时强化黄铁矿浮选使硫更高；提高充气量会加剧夹带和上浮；降低矿浆温度一般不利于浮选选择性。"},{"id":130,"type":"single","stem":"选矿厂磁选作业中，磁选机给矿浓度突然降低，对分选指标最可能的影响是","options":["精矿品位下降、回收率升高","精矿品位升高、回收率下降","精矿品位和回收率均升高","精矿品位和回收率均下降"],"answer":[1],"explanation":"知识点：磁选给矿浓度降低会使矿浆黏度下降、分选选择性提高，但磁性颗粒与磁场的碰撞概率降低，回收率下降。正确项精矿品位升高、回收率下降符合规律；浓度降低不会使品位下降；两者均升高或均下降均不符合磁选浓度影响规律。"},{"id":131,"type":"single","stem":"选矿厂磨矿作业中，磨机出现“胀肚”现象时，最先表现出的征兆是","options":["磨机排矿量增大且粒度变粗","磨机声音沉闷、排矿量减少","分级机溢流浓度降低","磨机电流明显下降"],"answer":[1],"explanation":"知识点：磨机胀肚时矿浆在筒内积聚，声音沉闷、排矿量减少。正确项声音沉闷、排矿量减少符合胀肚初期表现；排矿量增大且粒度变粗是磨机给矿不足或排矿口过大的表现；分级机溢流浓度降低多与补加水有关；磨机电流明显下降通常出现在空转或给矿中断时。"},{"id":132,"type":"single","stem":"某选矿厂浮选作业中，发现泡沫层变薄、泡沫发脆且精矿刮出量减少，检查起泡剂添加量正常，最可能的原因是","options":["矿浆pH值过低","浮选机充气量过大","捕收剂用量不足","矿浆温度过高"],"answer":[2],"explanation":"知识点：捕收剂不足会使矿物表面疏水性下降，泡沫层变薄、发脆、精矿产率降低。正确项捕收剂用量不足符合现象；pH过低通常影响矿物表面电性但不一定使泡沫发脆；充气量过大会使泡沫层翻动剧烈但不一定变薄；矿浆温度过高可能使泡沫不稳定，但起泡剂正常时捕收剂不足更直接。"},{"id":133,"type":"single","stem":"颚式破碎机工作中突然出现排料口堵塞，正确的处置顺序是","options":["立即停机断电，再清理堵塞物料","降低给矿量，让堵塞物料自行排出","加大排料口尺寸，继续给矿冲洗","先清理堵塞物料，再停机断电"],"answer":[0],"explanation":"知识点：破碎机堵料处置的安全程序。正确项先停机断电再做清理，可防止清理时设备意外启动或物料突然下落伤人。降低给矿量并不能解除已形成的堵塞；加大排料口边给矿边冲洗会让堵塞恶化且带负荷调整；先清理后停机违反停机断电原则，存在绞伤与启动风险。"},{"id":134,"type":"single","stem":"球磨机运转中给矿量不变但排矿粒度明显变粗，优先检查的项目是","options":["分级机返砂量与溢流浓度","磨机筒体衬板螺栓松紧","给矿皮带托辊润滑状态","磨机电机碳刷磨损程度"],"answer":[0],"explanation":"知识点：磨矿分级闭路中粒度变粗的原因排查。排矿粒度变粗多与分级返砂量减少或溢流浓度变化有关，故先查分级机返砂与溢流。衬板螺栓影响的是设备安全而非粒度；托辊润滑与碳刷磨损属于设备维护项，不直接造成粒度变化。"},{"id":135,"type":"single","stem":"浮选作业中矿浆pH值突然升高，对黄药类捕收剂浮选硫化矿最可能出现的影响是","options":["捕收能力下降，回收率降低","捕收能力增强，精矿品位升高","起泡量增大，泡沫层变薄","矿浆粘度下降，浮选速度加快"],"answer":[0],"explanation":"知识点：pH对黄药捕收硫化矿的影响。黄药在强碱性条件下易分解、在矿物表面吸附减弱，故捕收能力下降、回收率降低。pH升高不会增强黄药捕收能力；起泡量主要由起泡剂决定；矿浆粘度通常随pH升高略有增大而非下降。"},{"id":136,"type":"single","stem":"磁选机分选弱磁性矿物时，提高磁场强度后精矿品位反而下降，最可能的原因是","options":["连生体与脉石被机械夹杂带入精矿","磁性矿物颗粒发生了退磁现象","矿浆浓度过低导致分选变差","磁系转速过高使磁性矿物丢失"],"answer":[0],"explanation":"知识点：磁选场强与精矿品位的关系。场强过高会把磁性弱的连生体和夹杂脉石一并吸起，降低精矿品位。退磁现象与提高场强无关；矿浆浓度过低一般影响回收率而非直接降低品位；磁系转速过高会造成磁性矿物丢失，使回收率下降而非品位下降。"},{"id":137,"type":"single","stem":"浮选机充气量突然减小而电机电流正常，最应优先检查的部位是","options":["进气管路与风阀是否堵塞","电机皮带是否打滑","槽体衬板是否磨损","刮板转速是否下降"],"answer":[0],"explanation":"知识点：浮选机充气不足的故障判断。电机电流正常说明传动部分基本正常，充气量减小多因进气管路或风阀堵塞。皮带打滑会使电流或转速异常；衬板磨损影响槽体寿命；刮板转速与充气量无直接关系。"},{"id":138,"type":"single","stem":"一段开路破碎后产品中过大块增多，最合理的调整措施是","options":["适当减小排料口尺寸并检查齿板磨损","提高给矿速度以增加处理量","降低电机转速以减小破碎比","增大排料口尺寸以加快排料"],"answer":[0],"explanation":"知识点：破碎产品粒度的调整。过大块增多说明排料口偏大或齿板磨损，应减小排料口并检查齿板。提高给矿速度会加剧堵塞与粒度不均；降低电机转速会降低处理能力；增大排料口会使产品更粗。"},{"id":139,"type":"single","stem":"浮选泡沫层过厚、发粘且精矿品位偏低，最有效的调整方向是","options":["适当降低起泡剂用量并调整充气量","增加捕收剂用量以强化浮选","提高矿浆浓度以延长浮选时间","加大刮板速度以多刮出泡沫"],"answer":[0],"explanation":"知识点：泡沫性质与药剂制度的关系。泡沫过厚发粘多因起泡剂过量，应降低起泡剂并调整充气量。增加捕收剂会加剧夹杂；提高浓度延长浮选时间不解决泡沫粘问题；加大刮板速度只是多刮出已夹带的脉石，品位仍低。"},{"id":140,"type":"single","stem":"磨矿分级回路中返砂量突然增大、溢流变细，最可能的原因是","options":["分级机溢流堰高度被抬高","磨机给矿量突然减小","分级机螺旋提升速度加快","磨机排矿口被部分堵塞"],"answer":[0],"explanation":"知识点：分级机返砂量与溢流粒度的关系。溢流堰抬高会使沉降区变化、返砂增多且溢流变细。给矿量减小通常使返砂减少；螺旋提升速度加快会多排返砂使返砂量下降；排矿口堵塞会使磨机涨肚、返砂减少。"},{"id":141,"type":"single","stem":"磁选作业中发现精矿中磁性铁含量下降而尾矿磁性铁升高，正确的判断是","options":["磁性矿物在尾矿中流失，回收率下降","精矿品位提高，分选效果变好","磁选机磁场强度偏低导致品位下降","矿浆浓度过高导致分选变差"],"answer":[0],"explanation":"知识点：磁选指标判读。尾矿磁性铁升高说明磁性矿物进入尾矿，回收率下降。精矿品位与回收率是不同指标，此项不能说明品位提高；场强偏低会同时影响品位与回收率，但题干已给出尾矿流失的直接证据；浓度过高不是由题干数据推出的首要结论。"},{"id":142,"type":"single","stem":"浮选作业中矿浆温度过低导致药剂作用变慢，现场最常用的处理方式是","options":["适当增加药剂用量并延长搅拌时间","直接提高浮选机转速","降低矿浆浓度以加快反应","减少充气量以稳定泡沫"],"answer":[0],"explanation":"知识点：温度对浮选药剂作用的影响。低温下药剂分散与吸附变慢，常通过增加药量和延长搅拌来补偿。提高转速不能解决药剂作用慢；降低浓度会缩短药剂与矿物接触时间；减少充气量与药剂作用无关。"},{"id":143,"type":"single","stem":"某选矿厂磨矿工发现球磨机声音沉闷、排矿量减少且电流下降，下一步正确的处置是","options":["立即减少给矿并检查是否涨肚","立即加大给矿以稳定磨机负荷","提高分级机转速加快排料","向磨机内补加大球提高冲击力"],"answer":[0],"explanation":"知识点：磨机涨肚的判断与处置。声音沉闷、排矿减少、电流下降是涨肚典型征兆，应先减矿并检查。加大给矿会加重涨肚；提高分级机转速不能解决磨机内物料积压；补加大球与涨肚原因不符，且会加剧负荷。"},{"id":144,"type":"multi","stem":"浮选过程中出现精矿品位下降，可能的原因包括","options":["捕收剂用量过大","起泡剂用量过大","矿浆pH值控制不当","刮板速度过慢","给矿粒度变粗"],"answer":[0,1,2],"explanation":"知识点：浮选精矿品位下降的常见原因。捕收剂过量会使连生体与脉石上浮；起泡剂过量使泡沫粘夹脉石；pH控制不当会改变药剂选择性。刮板速度过慢只会减少精矿刮出量，不降低品位；给矿粒度变粗主要影响解离度与回收率，单凭变粗不能直接判定品位下降。"},{"id":145,"type":"single","stem":"颚式破碎机运行时突然出现排矿口明显变大且产品粒度变粗，最可能的原因是","options":["肘板断裂或推力板座脱落","动颚板齿板磨损均匀减薄","飞轮配重块固定螺栓松动","给矿粒度突然变小且均匀"],"answer":[0],"explanation":"肘板是颚破的保险件和传力件，断裂后动颚失去支撑，排矿口会突然张大、产品变粗，是典型故障特征。齿板均匀磨损会使排矿口缓慢变化而非突然变大；飞轮配重松动主要引起振动和电流波动；给矿变细不会导致排矿口变大。"},{"id":146,"type":"single","stem":"球磨机在给矿量、给水量和返砂量都不变的情况下，溢流粒度突然变粗，优先检查的项目是","options":["分级机溢流堰高度是否被磨损降低","磨机筒体衬板螺栓是否松动","给矿皮带秤是否计量漂移","浮选药剂添加量是否偏大"],"answer":[0],"explanation":"闭路磨矿中溢流堰高度直接决定分级返砂量和溢流细度，堰高被磨损降低会使溢流变粗而其他参数不变。衬板螺栓松动主要影响振动和漏浆；皮带秤漂移会改变给矿量，与题设不变矛盾；浮选药剂不改变磨矿分级粒度。"},{"id":147,"type":"single","stem":"浮选作业中矿浆pH值突然升高到12以上，对黄药类捕收剂浮选硫化铜矿最可能造成的影响是","options":["捕收剂效果下降，铜回收率降低","捕收剂选择性提高，精矿品位上升","矿浆黏度下降，浮选速度加快","气泡直径变小，泡沫层变薄"],"answer":[0],"explanation":"黄药在强碱性条件下易水解、在矿物表面吸附减弱，且石灰会抑制部分硫化矿，导致回收率下降。强碱不会提高黄药对铜矿的选择性；矿浆黏度与pH无直接对应关系；气泡大小主要由起泡剂和充气量决定。"},{"id":148,"type":"single","stem":"磁选机分选弱磁性赤铁矿时，为提高回收率通常采用的措施是","options":["提高磁场强度并减小矿浆流速","降低磁场强度并增大给矿量","减小磁系包角并加大冲洗水","降低筒体转速并减小磁偏角"],"answer":[0],"explanation":"赤铁矿属弱磁性矿物，需高磁场强度并延长矿粒在磁场中的停留时间，减小矿浆流速有利于弱磁性颗粒被吸附。降低场强、增大给矿量都会降低回收率；减小包角缩短分选弧长；降低转速和减小磁偏角不利于弱磁性矿物的分选。"},{"id":149,"type":"single","stem":"浮选机刮板刮出的泡沫层中，若精矿品位高但回收率低，最合适的调整方向是","options":["适当增加捕收剂用量并提高充气量","减少捕收剂用量并降低充气量","增大抑制剂用量并降低刮板速度","提高矿浆pH值并减少起泡剂"],"answer":[0],"explanation":"品位高回收率低说明目的矿物上浮量不足，需增强捕收和气泡携带能力，适当增加捕收剂、提高充气量可增加上浮量。减少捕收剂和充气量会进一步降低回收率；增大抑制剂会抑制目的矿物；提高pH并减少起泡剂不利于上浮。"},{"id":150,"type":"single","stem":"一段闭路磨矿中，旋流器沉砂口磨损扩大后，对磨矿分级系统最可能的影响是","options":["沉砂量增大，返砂比升高，磨机处理量下降","溢流粒度变细，循环负荷降低","旋流器进口压力升高，分级效率提高","溢流浓度升高，沉砂中细粒增多"],"answer":[0],"explanation":"沉砂口磨损扩大使更多物料从沉砂排出，返砂比升高，磨机内循环量增大，有效处理量下降。沉砂口扩大会使溢流变粗而非变细；循环负荷升高而非降低；进口压力由泵和管路决定，不会因沉砂口磨损而升高；溢流浓度通常降低。"},{"id":151,"type":"single","stem":"选矿厂破碎车间除尘系统中，袋式除尘器进出口压差持续升高且处理风量下降，正确的处置是","options":["检查并清灰或更换堵塞的滤袋","加大引风机转速强行提高风量","打开旁通阀让烟气不经过滤袋","向除尘器内喷水降低粉尘浓度"],"answer":[0],"explanation":"压差升高、风量下降是滤袋堵塞或清灰不良的典型表现，应检查清灰机构并清理或更换滤袋。加大风机转速不能解决堵塞且可能损坏设备；打开旁通会排放超标；喷水会糊袋加重堵塞。"},{"id":152,"type":"single","stem":"某铜硫矿浮选流程中，优先浮铜后再浮硫，现场发现铜精矿含硫偏高，优先采取的调整措施是","options":["在铜粗选作业适当增加石灰用量","在铜粗选作业增加丁基黄药用量","在硫浮选作业增加硫酸铜用量","在铜精选作业增加松醇油用量"],"answer":[0],"explanation":"铜精矿含硫偏高说明黄铁矿在铜回路被夹带上浮，增加石灰提高pH可抑制黄铁矿，降低铜精矿含硫。增加黄药会同时捕收黄铁矿，加重问题；硫酸铜用于活化硫浮选，不解决铜回路夹带；增加起泡剂只改变泡沫量，不改变选择性。"},{"id":153,"type":"single","stem":"阶段磨矿阶段选别流程相比一段磨矿一次选别流程的主要优点是","options":["减少过磨并降低后续作业负荷","提高磨机台时处理量并简化流程","降低选别作业对药剂用量的要求","减少分级机数量并缩短流程长度"],"answer":[0],"explanation":"阶段磨选在较粗粒度下先选出部分合格精矿和尾矿，只对连生体再磨再选，可减少有用矿物过磨和后续作业负荷。阶段磨选流程通常更复杂而非简化；台时处理量不一定提高；药剂用量不一定降低；设备数量一般增加。"},{"id":154,"type":"single","stem":"磁选作业中，磁选机精矿品位偏低且尾矿中磁性铁损失增加，最可能的原因是","options":["磁选机滚筒转速过高或冲洗水过大","磁选机磁场强度偏低且给矿过粗","磁选机磁偏角过小且精矿冲洗不足","给矿浓度过高且磁系包角过大"],"answer":[0],"explanation":"滚筒转速过高会缩短矿粒在磁场中的停留时间，冲洗水过大把已吸附的磁性矿粒冲入尾矿，造成精矿品位偏低且尾矿损失增加。磁场强度偏低主要降低回收率；磁偏角过小和冲洗不足会导致精矿品位偏低但尾矿损失不一定增加；给矿浓度过高主要影响分选效果。"},{"id":155,"type":"multi","stem":"选矿厂球磨机出现“胀肚”现象时，下列处置措施中正确的有","options":["适当减少给矿量并加大给水量","提高分级机溢流浓度以加快排矿","检查并清理磨机排矿口堵塞物","立即停止磨机运转并打开人孔放矿","降低磨机转速以减少矿石在筒内停留"],"answer":[0,2],"explanation":"胀肚是磨机内物料过多、排矿不畅，应减少给矿、加大给水并检查清理排矿口。提高溢流浓度会加重排矿困难；立即停机放矿可能造成大量物料沉积和事故扩大，应先减矿调节；降低转速会进一步降低排矿能力。"},{"id":156,"type":"single","stem":"颚式破碎机运行时，发现排矿口被大块矿石卡住导致飞轮转速明显下降，正确的第一步处置是","options":["立即停机并切断电源后再处理卡料","继续给矿等待大块自行排出","加大给矿量把卡块顶出去","打开排矿口调节装置边运行边调整"],"answer":[0],"explanation":"知识点：颚式破碎机卡料处置程序。破碎腔内卡大块时负荷骤增，必须先停机断电再处理，防止飞轮蓄能或突然转动伤人。继续给矿会加剧堵塞和过载；加大给矿量不能顶出卡块反而加重卡阻；运行中调整排矿口违反停机作业要求。"},{"id":157,"type":"single","stem":"球磨机排矿浓度突然变稀、返砂量增大，同时磨机声音沉闷，最可能的原因是","options":["给矿量偏大","给水量过大","钢球装载量不足","分级机溢流堰过高"],"answer":[1],"explanation":"知识点：磨矿浓度与声音、返砂的对应关系。给水过大使矿浆变稀、返砂增多、磨机声音沉闷。给矿量偏大时浓度应变浓、声音发闷但返砂不一定增大；钢球不足声音会变响、磨矿效率下降；溢流堰过高影响分级溢流细度而非直接使磨机声音沉闷。"},{"id":158,"type":"single","stem":"某铜矿浮选时发现精矿品位合格但回收率偏低，检查泡沫层较薄且发脆，优先考虑调整的操作是","options":["增加捕收剂用量并适当提高充气量","加大石灰用量抑制脉石","降低浮选机转速减少紊流","减少起泡剂用量使泡沫变脆"],"answer":[0],"explanation":"知识点：浮选泡沫状态与药剂调整。泡沫薄而脆说明捕收剂或起泡剂不足、矿化不充分，应增加捕收剂并适当提高充气量以增加矿化泡沫。加大石灰会抑制目的矿物；降转速会减少矿粒与气泡碰撞；减少起泡剂会使泡沫更脆更薄。"},{"id":159,"type":"single","stem":"浮选作业中矿浆pH值对药剂作用影响很大，用石灰调节pH时，石灰的主要作用之一是","options":["抑制黄铁矿并调节矿浆碱度","作为起泡剂增加泡沫量","作为捕收剂提高铜矿物疏水性","降低矿浆温度稳定浮选"],"answer":[0],"explanation":"知识点：石灰在浮选中的作用。石灰提高pH并抑制黄铁矿，是铜硫分离常用手段。石灰不是起泡剂，不起捕收作用，也不用于降低矿浆温度。"},{"id":160,"type":"single","stem":"旋流器分级时溢流跑粗、沉砂量减少，最可能与下列哪项操作有关","options":["给矿压力偏高","给矿浓度偏低","沉砂口磨损扩大","溢流管径偏小"],"answer":[2],"explanation":"知识点：旋流器结构与分级效果。沉砂口磨损扩大使沉砂排出过多、溢流相对跑粗减少沉砂量。给矿压力偏高通常分级更细；给矿浓度偏低会使溢流变粗但沉砂量不一定减少；溢流管径偏小会使溢流变细。"},{"id":161,"type":"single","stem":"破碎流程中，中碎前设置预先筛分的目的是","options":["提高破碎机处理能力并减少过粉碎","降低破碎机排矿口尺寸","增加破碎段数提高细度","替代检查筛分控制最终粒度"],"answer":[0],"explanation":"知识点：预先筛分的作用。预先筛分将细粒提前分出，减少破碎机负荷和过粉碎，提高处理能力。它不改变排矿口尺寸，不增加破碎段数，也不能替代检查筛分控制最终产品粒度。"},{"id":162,"type":"single","stem":"某选厂浮选铜硫分离作业中，精矿含硫超标，检查发现石灰添加点过于靠后，正确的改进方向是","options":["将石灰添加点前移至粗选前并保证搅拌时间","减少石灰用量避免抑制铜矿物","提高浮选机充气量强化硫上浮","增加捕收剂用量提高铜回收"],"answer":[0],"explanation":"知识点：抑制剂添加点与作用时间。石灰需在粗选前加入并有足够搅拌时间才能有效抑制黄铁矿。减少石灰会加重硫上浮；提高充气量和增加捕收剂都会使硫更多进入精矿。"},{"id":163,"type":"single","stem":"浮选机叶轮盖板间隙过大时，通常会出现","options":["充气量下降、矿浆循环变差","泡沫层变厚、精矿品位升高","矿浆温度明显升高","药剂用量自动减少"],"answer":[0],"explanation":"知识点：浮选机叶轮盖板间隙的影响。间隙过大会使吸气量和矿浆循环量下降，浮选效果变差。泡沫变厚、品位升高与间隙过大无必然关系；矿浆温度不会因此升高；药剂用量也不会自动减少。"},{"id":164,"type":"single","stem":"重选摇床操作中，床面横向坡度增大而其他条件不变，对分选的影响是","options":["矿粒沿横向排出加快，精矿带变窄","矿粒纵向运搬加快，精矿带变宽","水流层变厚，重矿物更易进入精矿","床面振动频率自动降低"],"answer":[0],"explanation":"知识点：摇床横向坡度与分选。横向坡度增大使横向水流速度加快，矿粒横向排出加快，精矿带变窄。纵向运搬由振动决定；水流层变薄而非变厚；振动频率不会自动改变。"},{"id":165,"type":"multi","stem":"关于浮选作业中矿浆浓度对浮选效果的影响，下列描述正确的有","options":["矿浆过浓时气泡负载增大，选择性可能变差","矿浆过稀时药剂浓度相对降低，浮选时间可能延长","粗粒矿物浮选通常宜采用较稀的矿浆","矿浆浓度越高精矿品位必然越高","矿浆浓度对浮选泡沫稳定性没有影响"],"answer":[0,1,2],"explanation":"知识点：矿浆浓度对浮选的影响。过浓使气泡负载大、选择性下降；过稀使药剂相对浓度降低、浮选时间延长；粗粒浮选宜较稀以利于颗粒悬浮。浓度高不必然提高品位，浓度也会影响泡沫稳定性，故后两项错误。"},{"id":166,"type":"single","stem":"选矿厂破碎车间，颚式破碎机运转中突然出现排矿口堵塞，下列处置顺序中最合理的是","options":["先停机并切断电源，再清理堵塞物料，确认无异常后重新启动","先加大给矿量把堵塞物料顶下去，再视情况决定是否停机","先用水冲洗排矿口，待物料松动后继续给矿运行","先松开排矿口调整装置放大排矿口，再继续给矿运行"],"answer":[0],"explanation":"知识点：颚式破碎机堵塞的安全处置程序。正确项先停机断电再清理，符合设备检修必须先切断动力源的安全操作原则。加大给矿量会加剧堵塞甚至损坏设备；用水冲洗不能解决颚破排矿口堵塞且可能造成物料黏结；带料调整排矿口会在设备运转中造成调整机构损伤或物料喷出伤人。"},{"id":167,"type":"single","stem":"球磨机磨矿作业中，给矿量不变而返砂量明显增大、磨机排矿粒度变粗，最可能的原因是","options":["磨机转速偏低","分级机溢流堰过高","磨机内钢球充填率过高","给矿中细粒级含量偏高"],"answer":[1],"explanation":"知识点：磨矿分级闭路中返砂量与分级设备的关系。溢流堰过高会使分级机溢流变粗、返砂量增大，同时磨机排矿粒度变粗。磨机转速偏低会使磨矿效果变差但返砂量通常不会明显增大；钢球充填率过高会使磨矿更细而非变粗；给矿细粒级偏高会使返砂量减少。"},{"id":168,"type":"single","stem":"浮选作业中，矿浆pH值对捕收剂作用影响显著，浮选硫化矿时常用石灰调节矿浆的","options":["酸度","碱度","浓度","温度"],"answer":[1],"explanation":"知识点：浮选矿浆pH调节。石灰是常用的碱性调整剂，用于提高矿浆碱度，抑制黄铁矿等硫化矿物。酸度由硫酸等酸性药剂调节；浓度指矿浆固含量；温度由加热或冷却控制，均与石灰的主要作用不符。"},{"id":169,"type":"single","stem":"磁选作业中，处理强磁性矿物（如磁铁矿）时，通常采用的磁选机类型是","options":["弱磁场磁选机","强磁场磁选机","高梯度磁选机","超导磁选机"],"answer":[0],"explanation":"知识点：磁选机磁场强度与矿物磁性匹配。磁铁矿属强磁性矿物，用弱磁场磁选机即可有效分选。强磁场磁选机用于弱磁性矿物；高梯度磁选机用于微细粒弱磁性矿物；超导磁选机用于特殊弱磁性物料，对强磁性矿物既不经济也无必要。"},{"id":170,"type":"single","stem":"某选矿厂浮选铜硫矿石，现场发现铜精矿品位下降而回收率变化不大，镜检发现精矿中含较多黄铁矿，下列调整措施中最直接有效的是","options":["增加石灰用量提高矿浆pH抑制黄铁矿","增加捕收剂用量提高铜矿物浮选速度","降低浮选机充气量减少泡沫夹带","提高矿浆浓度以增强药剂作用"],"answer":[0],"explanation":"知识点：浮选选择性抑制。黄铁矿进入铜精矿导致品位下降，提高矿浆pH是抑制黄铁矿的常用手段。增加捕收剂会同时浮起更多黄铁矿；降低充气量影响所有矿物回收且不解决选择性；提高矿浆浓度不改变矿物表面疏水性差异。"},{"id":171,"type":"single","stem":"在磨矿分级回路中，螺旋分级机返砂返回球磨机的目的是","options":["提高磨机给矿品位","使不合格粒级再磨","降低磨机给矿水分","增加磨机处理量"],"answer":[1],"explanation":"知识点：闭路磨矿分级流程。返砂是分级机分出的不合格粗粒级，返回磨机再磨，保证最终产品粒度合格。返砂不改变给矿品位；不主要起降低水分作用；返砂会占用磨机处理能力而非增加处理量。"},{"id":172,"type":"single","stem":"浮选机运转中，矿浆液面翻花严重、泡沫层不稳定，下列原因中最可能是","options":["充气量过大","捕收剂用量不足","矿浆pH值过高","浮选机转速偏低"],"answer":[0],"explanation":"知识点：浮选机充气量与泡沫层稳定性。充气量过大会造成液面翻花、泡沫层紊乱。捕收剂不足会使泡沫稀少而非翻花；pH过高主要影响矿物可浮性；转速偏低会使充气搅拌不足，泡沫层反而平静。"},{"id":173,"type":"single","stem":"选矿厂使用永磁筒式磁选机时，为减少磁滚筒表面附着物影响分选效果，正确的日常操作是","options":["定期停机清理滚筒表面并检查卸矿水管","运行时用钢刷贴近滚筒表面清刷","运行时用铁棒敲击滚筒外壳震落附着物","提高矿浆浓度使附着物自行脱落"],"answer":[0],"explanation":"知识点：磁选机维护操作。正确做法是停机清理并检查卸矿水，保证卸矿效果。运行中用钢刷清刷会损伤滚筒且不安全；用铁棒敲击会损坏设备并干扰磁场；提高浓度只会加重附着和夹带。"},{"id":174,"type":"single","stem":"某选矿厂球磨机运行中轴承温度持续升高并伴有异常振动，现场人员下一步最合理的处置是","options":["立即停机检查润滑和轴承状况","继续运行并加强观察温度变化","降低磨机转速继续维持生产","加大给矿量使磨机负荷变化缓解振动"],"answer":[0],"explanation":"知识点：磨机异常工况处置。轴承温度持续升高伴振动是设备故障征兆，应立即停机检查，防止烧瓦或断轴。继续观察可能错过处置时机；降速运行不能消除故障；加大给矿量会加重负荷和振动。"},{"id":175,"type":"single","stem":"浮选药剂中，松醇油在铜铅锌硫化矿浮选中主要起的作用是","options":["起泡剂","捕收剂","抑制剂","调整剂"],"answer":[0],"explanation":"知识点：浮选药剂分类与作用。松醇油是常用起泡剂，能降低气泡表面张力、稳定泡沫层。捕收剂用于增强矿物疏水性；抑制剂用于抑制特定矿物；调整剂用于调节矿浆性质，均不是松醇油的主要作用。"},{"id":176,"type":"single","stem":"某选矿厂磁选车间处理磁铁矿，发现精矿品位偏低且尾矿中磁性铁含量偏高，下列检查项目中最应先排查的是","options":["磁选机磁场强度是否下降","磨矿细度是否过磨","浮选药剂是否过量","分级机溢流浓度是否过高"],"answer":[0],"explanation":"知识点：磁选指标异常的排查。精矿品位低且尾矿磁性铁高，说明磁选机分选效果差，应优先检查磁场强度、磁块是否脱落或退磁。过磨主要影响粒度组成；浮选药剂与磁选作业无关；溢流浓度影响分级但非磁选指标恶化的首选排查项。"},{"id":177,"type":"single","stem":"选矿厂破碎车间一台颚式破碎机排矿口调至15mm后，给矿粒度仍为300mm，出现频繁堵矿，最可能的原因是","options":["给矿粒度超过破碎机允许最大给矿尺寸","排矿口调得过大导致物料过粉碎","偏心轴转速偏低使物料停留时间过长","衬板磨损后破碎腔容积变小"],"answer":[0],"explanation":"颚式破碎机给矿粒度一般不超过给矿口宽度的0.8～0.85倍，300mm给矿配15mm排矿口显然给矿过大，容易堵矿。排矿口过大不会造成过粉碎，只会使产品变粗；偏心轴转速偏低主要影响处理能力，不是堵矿主因；衬板磨损使破碎腔变大而非变小。"},{"id":178,"type":"single","stem":"球磨机在正常运转中突然出现排矿量下降、返砂量明显增大、磨机声音发闷，最可能发生的情况是","options":["磨机内物料过多形成胀肚","磨机内钢球量不足","给矿粒度突然变细","分级机溢流浓度降低"],"answer":[0],"explanation":"排矿量下降、返砂量增大、声音发闷是磨机胀肚的典型征兆，说明磨内物料积聚过多。钢球不足会使磨矿能力下降但声音不会发闷；给矿粒度过细一般使返砂减少；溢流浓度降低通常与补加水有关，不会造成返砂量增大。"},{"id":179,"type":"single","stem":"浮选作业中，矿浆pH值升高到11以上时，黄药类捕收剂对硫化矿的捕收能力明显下降，主要原因是","options":["高pH下黄药易被氧化分解","高pH下硫化矿表面生成亲水氧化膜","高pH使矿浆黏度增大阻碍气泡矿化","高pH使起泡剂失去起泡能力"],"answer":[1],"explanation":"高碱条件下硫化矿表面会生成亲水的氢氧化物或氧化膜，抑制捕收剂吸附，使浮选变差。黄药在碱性条件下相对稳定，并非主要被氧化分解；矿浆黏度变化不是主因；起泡剂在碱性条件下仍能起泡。"},{"id":180,"type":"single","stem":"磁选机分选弱磁性矿物时，为提高回收率而增大磁感应强度后，精矿品位反而下降，最合理的调整措施是","options":["减小磁选机给矿量并增大冲洗水量","继续提高磁感应强度以强化回收","降低磁选机筒体转速至最低","停止补加水使矿浆浓度升高"],"answer":[0],"explanation":"磁感应强度过高会把连生体和脉石也选入精矿，导致品位下降，应适当减小给矿量并加大冲洗水以加强机械夹杂的排出。继续提高场强会进一步降低品位；筒体转速过低会减薄料层但不利于分选；停止补水提高浓度会加重夹杂。"},{"id":181,"type":"single","stem":"某选矿厂浮选流程中，粗选精矿再磨后进入精选，这种配置的主要目的是","options":["使连生体解离后再提高精矿品位","降低粗选作业的药剂消耗","提高粗选作业的回收率","减少精选作业的矿浆量"],"answer":[0],"explanation":"粗精矿再磨是为了使粗选得到的连生体进一步解离，再经精选提高最终精矿品位。降低粗选药剂消耗、提高粗选回收率、减少精选矿量都不是再磨的核心目的。"},{"id":182,"type":"single","stem":"在选矿厂中，将破碎产品先筛分、筛下物直接进入磨矿、筛上物返回破碎机的作业称为","options":["预先筛分","检查筛分","准备筛分","脱水筛分"],"answer":[1],"explanation":"检查筛分用于控制破碎最终产品粒度，筛上物返回再破碎，形成闭路。预先筛分是在破碎前分出合格粒级；准备筛分是为下一步作业准备合适粒级；脱水筛分用于降低物料水分。"},{"id":183,"type":"single","stem":"浮选机内矿化气泡上浮到泡沫层后，操作工用刮板将泡沫刮出，这一过程属于浮选流程中的","options":["矿化作用","分离作用","刮泡排出","调浆作业"],"answer":[2],"explanation":"刮泡排出是将已矿化的泡沫产品从浮选机中排出，属于浮选产品的排出环节。矿化作用是气泡与矿粒附着；分离作用通常指泡沫与矿浆的分离；调浆是浮选前的搅拌调药。"},{"id":184,"type":"single","stem":"某磁铁矿选矿厂一段磨矿分级溢流浓度为45%，二段磁选精矿浓度偏低，操作工发现磁选机给矿管有堵塞，正确的下一步处置是","options":["立即停机并清理给矿管后恢复","继续运行并加大给矿压力冲开堵塞","关闭磁选机冲洗水提高浓度","把磁选机筒体转速调高处理堵塞"],"answer":[0],"explanation":"给矿管堵塞会造成给矿不均和浓度异常，必须先停机清理，防止设备损坏和指标恶化。加大给矿压力可能使管道进一步损坏；关闭冲洗水与堵塞无关且会影响精矿质量；调高筒体转速不能解决管道堵塞。"},{"id":185,"type":"single","stem":"浮选过程中加入石灰的主要作用之一是","options":["调节矿浆pH并抑制黄铁矿","作为起泡剂增强泡沫稳定性","作为捕收剂提高硫化矿可浮性","降低矿浆温度防止药剂分解"],"answer":[0],"explanation":"石灰是常用的pH调整剂，提高碱度后可抑制黄铁矿等硫化矿物。石灰不是起泡剂，也不是捕收剂，更不能降低矿浆温度。"},{"id":186,"type":"single","stem":"某选矿厂球磨机排矿口出现大量粗粒级物料，经检查给矿量、给水量均正常，最可能的原因是","options":["钢球充填率偏低或球径偏小","分级机溢流浓度偏高","磨机转速超过临界转速","给矿中细粒级含量增加"],"answer":[0],"explanation":"钢球充填率不足或球径偏小会降低磨矿能力，使排矿中粗粒增多。分级机溢流浓度偏高影响分级效率但不直接使排矿变粗；转速超过临界转速钢球会离心化，但实际运行中很少出现；给矿细粒增加会使产品变细而非变粗。"},{"id":187,"type":"single","stem":"颚式破碎机运行时突然发出金属撞击声且排料口有铁块卡住，正确的处置顺序是","options":["立即停机断电，待破碎腔物料清空后再取出铁块","降低给矿量继续运转，让铁块自然从排料口挤出","提高主轴转速把铁块强行挤碎后排出","先打开排料口调大间隙，等铁块落下再恢复生产"],"answer":[0],"explanation":"知识点：颚破卡铁块的安全处置。正确项先停机断电再清腔取铁是防止设备损坏和人员伤害的标准程序。降低给矿量继续运转会让铁块继续挤压齿板造成断裂；提高转速强行挤碎会加剧过铁损伤；先调大排料口不解决铁块卡死位置且仍带电作业有危险。"},{"id":188,"type":"single","stem":"浮选过程中发现精矿泡沫层变薄、颜色变浅、回收率下降，优先检查的是","options":["捕收剂添加量和起泡剂用量是否发生变化","球磨机钢球补加量是否按周期执行","磁选机磁场强度是否调整过","浓密机底流浓度是否升高"],"answer":[0],"explanation":"知识点：浮选泡沫状态与药剂制度的关系。正确项泡沫变薄变浅、回收率下降首先与捕收剂和起泡剂用量变化相关。钢球补加量影响磨矿细度但不直接决定泡沫层厚度；磁选机磁场强度与浮选作业无关；浓密机底流浓度属后续脱水环节。"},{"id":189,"type":"single","stem":"磁选机分选效果变差、精矿品位下降，检查发现给矿中矿浆浓度明显偏低，正确的调整方向是","options":["提高给矿浓度至工艺规定范围后再观察分选指标","降低磁选机滚筒转速以延长分选时间","增大磁选机磁场强度来弥补浓度不足","减小冲洗水量以提高精矿品位"],"answer":[0],"explanation":"知识点：磁选给矿浓度对分选指标的影响。正确项浓度偏低会加剧矿粒分散、降低选择性，应先恢复到工艺规定浓度。降低滚筒转速不能解决浓度问题；增大磁场强度会把脉石一起吸上来降低品位；减小冲洗水在浓度偏低时反而使夹杂更严重。"},{"id":190,"type":"single","stem":"浮选作业中矿浆pH值需要提高时，现场通常添加的调整剂是","options":["石灰乳","硫酸铜","松醇油","丁基黄药"],"answer":[0],"explanation":"知识点：浮选pH调整剂种类。正确项石灰乳是常用的碱性调整剂，可提高矿浆pH。硫酸铜是活化剂；松醇油是起泡剂；丁基黄药是捕收剂，三者都不用于提高pH。"},{"id":191,"type":"single","stem":"圆锥破碎机出现过铁后保险弹簧被压缩、排料口变大，恢复正常生产前应当","options":["检查弹簧和机架有无损伤并重新调整排料口","直接拧紧弹簧到比原设定更紧再开机","只把排料口调小即可忽略弹簧状态","更换全部破碎壁后再重新设定排料口"],"answer":[0],"explanation":"知识点：圆锥破过铁后的检查与复位。正确项应先检查弹簧、机架等有无损伤并重新调整排料口。直接拧更紧会使保险失效；只调排料口忽略弹簧损伤会留下隐患；更换全部破碎壁属过度维修且不检查弹簧仍不安全。"},{"id":192,"type":"single","stem":"水力旋流器溢流跑粗、底流夹细同时出现，最可能的原因是","options":["给矿压力偏低且给矿浓度偏高","沉砂嘴直径偏大且给矿压力偏高","溢流管直径偏小且给矿浓度偏低","给矿粒度整体偏细且压力稳定"],"answer":[0],"explanation":"知识点：旋流器分级异常原因分析。正确项给矿压力偏低使离心力不足，浓度偏高使矿浆黏度增大，导致溢流跑粗、底流夹细。沉砂嘴偏大主要引起底流浓度降低；溢流管偏小会使溢流变细；给矿偏细且压力稳定时分级应正常。"},{"id":193,"type":"single","stem":"一段磨矿分级回路中返砂量突然大幅增加，优先排查的是","options":["磨机给矿量是否突增或磨机内钢球是否减少","分级机溢流堰高度是否被人为调低","旋流器沉砂嘴是否更换为更大直径","浓密机耙架转速是否发生变化"],"answer":[0],"explanation":"知识点：返砂量变化的原因排查。正确项给矿量突增或钢球减少会使磨矿产品变粗、返砂量增加。溢流堰调低会使返砂量减少；沉砂嘴增大属二段旋流器内容；浓密机耙架转速与磨矿分级回路返砂无关。"},{"id":194,"type":"single","stem":"浮选流程中粗选精矿进入精选前需要添加石灰抑制黄铁矿，现场操作工正确的做法是","options":["将石灰乳按工艺规定加入精选作业的搅拌槽中","把石灰直接干粉撒在精选浮选机泡沫槽内","在粗选作业末尾一次性加入全部石灰","将石灰加入球磨机给矿口与矿石一起磨"],"answer":[0],"explanation":"知识点：浮选抑制剂添加地点。正确项石灰乳应按规定加入精选前的搅拌槽，保证与矿浆充分接触。干粉撒在泡沫槽无法与矿浆作用；粗选末尾一次加入会影响粗选指标；加入磨机给矿口会使石灰在磨矿中过度作用且影响后续作业。"},{"id":195,"type":"single","stem":"磁选机给矿中含有大量木屑和碎布等杂物，对分选的主要影响是","options":["杂物堵塞给矿口和分选间隙，造成精矿品位波动","杂物会提高磁场强度使精矿品位上升","杂物会降低矿浆浓度使分选更容易","杂物会与磁性矿物反应改变矿物性质"],"answer":[0],"explanation":"知识点：磁选给矿除杂的必要性。正确项杂物会堵塞给矿口和分选间隙，造成分选不稳定和品位波动。杂物不会提高磁场强度；会改变矿浆流动状态而非降低浓度使分选更容易；也不会与磁性矿物发生化学反应。"},{"id":196,"type":"single","stem":"选矿厂破碎车间巡检时发现颚式破碎机排矿口明显变大，产品粒度变粗，首先应检查的部位是","options":["肘板是否断裂或变形","推力板座螺栓是否松动","齿板磨损情况与排矿口调整装置","飞轮配重块是否移位"],"answer":[2],"explanation":"知识点是颚式破碎机排矿口变大的常见原因。齿板磨损后实际排矿口会变大，调整装置松动也会导致排矿口变化，故应首先检查齿板与调整装置。肘板断裂会使设备停机而非排矿口变大；推力板座螺栓松动主要引起异响和振动；飞轮配重块移位影响平衡，不直接改变排矿口。"},{"id":197,"type":"single","stem":"浮选作业中，矿浆pH值突然升高，现场最先应做的是","options":["立即加大捕收剂用量","检查石灰添加量与pH检测仪表","停加起泡剂并提高充气量","降低浮选机液位以加快排矿"],"answer":[1],"explanation":"知识点是浮选pH异常时的处置程序。pH突然升高通常由石灰添加过量或仪表失准引起，应先检查添加量与检测仪表。加大捕收剂会加剧药剂制度混乱；停加起泡剂与pH升高无直接对应关系；降低液位改变浮选停留时间，不能解决pH异常。"},{"id":198,"type":"single","stem":"磁选机精矿品位偏低、尾矿中磁性铁损失增加，检查发现磁选机滚筒表面矿浆流速过快，较合理的调整是","options":["增大给矿量以提高处理量","适当减小冲洗水量并降低给矿浓度","提高磁选机转速到最大","加大磁偏角使精矿提前排出"],"answer":[1],"explanation":"知识点是磁选机操作参数对分选效果的影响。矿浆流速过快会冲走磁性矿粒，适当减小冲洗水量、降低给矿浓度可改善分选。增大给矿量会进一步加快流速；转速调到最大会缩短分选时间；加大磁偏角使精矿提前排出会降低回收效果。"},{"id":199,"type":"single","stem":"选矿厂浓密机溢流跑浑，检查发现给矿量未变而底流泵排出量明显减小，最可能的原因是","options":["给矿浓度突然降低","絮凝剂添加量不足","底流泵或排矿管路堵塞","浓密机耙架转速过高"],"answer":[2],"explanation":"知识点是浓密机跑浑的原因判断。底流排出量减小会导致机内矿浆液面上升、沉泥层上移，引起溢流跑浑，常见原因是底流泵或管路堵塞。给矿浓度降低会减轻浓密机负荷；絮凝剂不足会影响沉降速度但底流排出量一般不会明显减小；耙架转速过高影响不大，且不一定导致跑浑。"},{"id":200,"type":"single","stem":"球磨机运转中听到筒体内有金属撞击声且电流波动，同时排矿量下降，正确的处置是","options":["继续观察并加大给矿量","立即停机检查筒体衬板与钢球","降低磨机转速后继续运行","加大排矿水量冲洗筒体"],"answer":[1],"explanation":"知识点是磨机异常声响的处置。金属撞击声伴电流波动、排矿量下降，多为衬板松动脱落或钢球窜出，应立即停机检查。继续加大给矿会加剧设备损坏；降低转速不能消除松动衬板隐患；加大排矿水不能解决筒内机械故障。"},{"id":201,"type":"single","stem":"浮选作业中，抑制剂用量过大时最可能出现的现象是","options":["目的矿物上浮量明显减少","脉石矿物上浮量明显增加","泡沫层变薄且易破裂","矿浆pH值急剧下降"],"answer":[0],"explanation":"知识点是抑制剂用量对浮选的影响。抑制剂过量会抑制目的矿物，使其上浮量减少。脉石上浮量增加是抑制不足或捕收剂过量；泡沫层变薄多与起泡剂不足有关；抑制剂一般不直接引起pH急剧下降。"},{"id":202,"type":"single","stem":"某选矿厂磁选作业给矿中混入大量粗粒废石，磁选精矿品位下降，现场较合理的处理是","options":["提高磁选机磁场强度","在磁选前增设筛分或预先分级","加大磁选机给矿水量","降低磁选机滚筒转速"],"answer":[1],"explanation":"知识点是磁选给矿粒度对分选的影响。粗粒废石混入会降低精矿品位，应在磁选前通过筛分或分级去除。提高磁场强度会同时吸起更多连生体和废石；加大给矿水量不能解决粗粒废石问题；降低滚筒转速延长分选时间，对粗粒废石分选效果有限。"},{"id":203,"type":"single","stem":"颚式破碎机运行中排矿口被大块矿石卡住，正确的处置顺序是","options":["立即停机断电，挂牌上锁后清除卡块","保持运转用铁棍撬出卡块","先给料再加大排矿口冲走卡块","停给料但不停机，用水冲走卡块"],"answer":[0],"explanation":"知识点：破碎机卡料处置的停机安全程序。正确项先停机断电挂牌上锁再清除，能防止设备突然启动或飞溅伤人。错误项B保持运转撬料，撬棍易被反击飞或卷入；错误项C先给料会加重堵塞；错误项D不停机冲水，仍存在运转部件伤人风险。"},{"id":204,"type":"single","stem":"圆锥破碎机采用挤满给矿方式运行时，给矿量应控制为","options":["使破碎腔在整个圆周上充满矿石","只让矿石从给矿口一侧落下","保持给矿量约为破碎腔容积的一半","按排矿口宽度的整数倍定量给入"],"answer":[0],"explanation":"知识点：圆锥破碎机挤满给矿的操作要求。正确项A是挤满给矿的定义，即矿石充满破碎腔并均匀分布于圆周。错误项B单侧落料会造成偏磨和粒度不均；错误项C半腔给矿属于非挤满给矿；错误项D按排矿口宽度定量给矿无此操作依据。"},{"id":205,"type":"single","stem":"球磨机运行中出现排矿粒度明显变粗、返砂量增大，首先应检查的是","options":["给矿量是否突然增大或给矿粒度变粗","分级机溢流堰是否被异物堵塞","磨机筒体衬板是否安装方向错误","润滑油泵是否处于自动启停状态"],"answer":[0],"explanation":"知识点：磨矿分级闭路中产品变粗的原因判断。正确项A给矿量增大或给矿变粗会缩短矿粒在磨机内停留时间，导致排矿变粗、返砂增多。错误项B溢流堰堵塞会使溢流变细而非变粗；错误项C衬板方向问题影响的是磨矿效率，不是粒度突然变粗的首要因素；错误项D润滑系统与磨矿粒度无直接关系。"},{"id":206,"type":"single","stem":"浮选机停机时间较长需要重新开车时，对浮选槽内矿浆的正确处理是","options":["先通气搅拌并检查药剂制度后再逐步给矿","直接按正常给矿量满负荷开车","放空槽内矿浆后空槽启动浮选机","先加大量起泡剂再启动刮板"],"answer":[0],"explanation":"知识点：浮选机长时间停车后的开车程序。正确项A先通气搅拌使矿浆悬浮并确认药剂条件，再逐步给矿，可避免沉槽和跑槽。错误项B直接满负荷给矿易造成沉槽和精矿质量波动；错误项C空槽启动会造成刮板空转、矿浆未建立浮选环境；错误项D先加大起泡剂会造成大量泡沫无法控制。"},{"id":207,"type":"single","stem":"磁选机给矿浓度过高时，最可能出现的分选效果变化是","options":["磁性矿粒与非磁性矿粒的分离选择性下降","磁性矿粒所受磁力明显增强","非磁性矿粒被磁化的程度显著提高","精矿品位和回收率同时稳定不变"],"answer":[0],"explanation":"知识点：磁选给矿浓度对分选效果的影响。正确项A浓度过高使矿浆黏度增大，矿粒分散变差，夹杂增多，分离选择性下降。错误项B磁力由磁场和矿粒性质决定，不因浓度升高而增强；错误项C非磁性矿粒不会被明显磁化；错误项D品位和回收率通常会波动，不可能稳定不变。"},{"id":208,"type":"single","stem":"浮选过程中发现精矿泡沫颜色变浅、泡沫变脆且精矿品位下降，最可能的原因是","options":["抑制剂用量不足或捕收剂选择性变差","起泡剂用量过少导致泡沫量减少","浮选机充气量突然降低","矿浆温度低于正常操作范围"],"answer":[0],"explanation":"知识点：浮选精矿品位下降的常见原因判断。正确项A抑制剂不足或捕收剂选择性差会使脉石矿物上浮，精矿品位下降，泡沫颜色变浅。错误项B起泡剂少主要影响泡沫量和稳定性，不是品位下降的主因；错误项C充气量降低会使浮选变慢，泡沫量减少；错误项D温度偏低影响浮选速度，但典型表现不是泡沫变脆和颜色变浅。"},{"id":209,"type":"single","stem":"一段磨矿与分级构成闭路时，分级机返砂的正确去向是","options":["返回一段磨机再磨","直接进入浮选作业","送入二段磨机给矿","作为最终尾矿排出"],"answer":[0],"explanation":"知识点：闭路磨矿中返砂的处理。正确项A分级机返砂是粒度不合格的粗粒，应返回一段磨机再磨。错误项B返砂粒度粗，直接进浮选会造成单体解离不足；错误项C一段闭路的返砂不应直接送入二段磨机，流程配置不同；错误项D返砂含目的矿物，排为尾矿会造成金属流失。"},{"id":210,"type":"single","stem":"浮选作业中，石灰在铜硫分离时的主要作用是","options":["抑制黄铁矿并调节矿浆pH","活化黄铜矿提高上浮率","作为起泡剂增加泡沫量","作为捕收剂直接捕收铜矿物"],"answer":[0],"explanation":"知识点：铜硫分离中石灰的作用。正确项A石灰提高矿浆pH，抑制黄铁矿上浮，实现铜硫分离。错误项B石灰对黄铜矿不是活化剂；错误项C石灰无起泡性能；错误项D石灰不是捕收剂，不能直接捕收铜矿物。"},{"id":211,"type":"single","stem":"磁选机给矿中混入大量粗粒木屑和碎布时，对分选过程最直接的影响是","options":["堵塞给矿管和分选腔，造成分选中断","提高磁性矿粒的磁化强度","降低非磁性矿粒的沉降速度","使磁选机磁场强度自动增大"],"answer":[0],"explanation":"知识点：磁选给矿中杂物的危害。正确项A木屑碎布易在给矿管和分选腔中缠绕堵塞，导致分选中断。错误项B杂物不会提高矿粒磁化强度；错误项C杂物影响的是通过性，不是非磁性矿粒沉降速度；错误项D磁场强度由设备设定，不会自动增大。"},{"id":212,"type":"single","stem":"浮选机运行中突然出现泡沫大量外溢，正确的第一步处置是","options":["立即减小充气量并适当降低矿浆液位","立即向槽内加大量清水稀释","立即停止刮板运转并打开放矿阀","立即提高捕收剂添加量稳定泡沫"],"answer":[0],"explanation":"知识点：浮选跑槽的应急处理。正确项A先减小充气量、降低液位，可迅速控制泡沫外溢。错误项B加大量清水会改变矿浆浓度和药剂条件，且见效慢；错误项C停刮板会加剧精矿堆积，不能控制外溢；错误项D提高捕收剂会加重泡沫量和跑槽。"},{"id":213,"type":"single","stem":"棒磨机与球磨机相比，在选矿厂中更常被用于","options":["粗磨或防止过粉碎的磨矿作业","细磨至几十微米的作业","与分级机构成闭路的细磨作业","处理黏性大的矿石的擦洗作业"],"answer":[0],"explanation":"知识点：棒磨机与球磨机的适用场合区分。正确项A棒磨机以线接触为主，产品粒度均匀、过粉碎少，适合粗磨或防止过粉碎。错误项B细磨至几十微米通常用球磨机；错误项C闭路细磨也以球磨机为主；错误项D擦洗作业有专门的擦洗机，不是棒磨机的主要用途。"},{"id":214,"type":"single","stem":"颚式破碎机运行中突然出现排料口堵塞且主机电流升高，正确的第一步处置是","options":["立即切断主电机电源并挂牌","先减小给矿量再观察电流变化","打开排料口调整装置放大排料口","向破碎腔注水冲洗堵塞物料"],"answer":[0],"explanation":"知识点：颚式破碎机堵塞处置。先停机断电挂牌是防止带载强行运转损坏设备或伤人；减小给矿量不能解决已堵塞的料层；带载调整排料口会别劲损坏调整机构；注水冲洗对颚破堵塞无效且可能造成泥化。"},{"id":215,"type":"single","stem":"球磨机排矿浓度偏大、返砂量明显减少时，优先采取的调整措施是","options":["适当增加给水量","提高分级机转速","加大磨机给矿量","降低磨机转速率"],"answer":[0],"explanation":"知识点：磨矿分级浓度调节。排矿浓度大说明水少，增加给水量可降低浓度、增加返砂；提高分级机转速会提高返砂返磨量但不能解决浓度大；加大给矿会进一步增浓；降低转速减少排料反而恶化。"},{"id":216,"type":"single","stem":"浮选机运行中泡沫层变薄、颜色发暗且精矿品位下降，最可能是","options":["起泡剂用量偏大","捕收剂用量偏大","矿浆浓度偏低","浮选机充气量偏大"],"answer":[1],"explanation":"知识点：浮选药剂用量与泡沫现象。捕收剂过量使脉石上浮，泡沫发暗、品位下降；起泡剂偏大泡沫会变厚变脆；浓度偏低泡沫层薄但颜色不暗；充气量偏大泡沫量大而虚。"},{"id":217,"type":"single","stem":"磁选机精矿品位偏低而回收率尚可时，可优先调整的操作参数是","options":["减小磁选机给矿量","降低磁系偏角","增大磁选机筒体转速","降低冲洗水量"],"answer":[2],"explanation":"知识点：磁选机操作参数。提高筒体转速可增加离心力甩掉夹杂脉石，提高品位；减小给矿量对品位改善有限；降低磁系偏角影响精矿排出；降低冲洗水会减少脉石冲走使品位更低。"},{"id":218,"type":"single","stem":"振动筛筛孔堵塞后筛下产物量减少，正确的处理方式是","options":["停机用钢钎逐个捅孔","降低给矿量继续运行","加大筛面倾角","提高振动频率"],"answer":[0],"explanation":"知识点：振动筛堵塞清理。停机用钢钎捅孔是标准清理办法；带料继续运行会加重堵塞并磨损筛网；加大倾角、提高频率对已堵塞筛孔无改善作用。"},{"id":219,"type":"single","stem":"浮选作业中矿浆pH值突然升高，对黄药类捕收剂的影响是","options":["捕收能力增强","捕收能力减弱","起泡能力增强","选择性提高"],"answer":[1],"explanation":"知识点：pH对黄药浮选的影响。黄药在强碱性条件下易分解、捕收能力下降；pH升高不会增强黄药捕收或起泡能力；选择性变化需配合其他条件，不能一概而论。"},{"id":220,"type":"single","stem":"一段闭路磨矿中返砂比突然增大且磨机声响沉闷，说明","options":["磨机内矿量偏多","磨机内矿量偏少","分级机溢流跑粗","给矿粒度变细"],"answer":[0],"explanation":"知识点：磨机负荷判断。声响沉闷、返砂比大说明磨机内物料多；矿量偏少时声响清脆返砂少；溢流跑粗与返砂比无直接对应；给矿变细会使返砂减少。"},{"id":221,"type":"single","stem":"某选厂铜硫混合精矿分离浮选用石灰抑制硫，现场发现硫精矿含铜升高，首先应检查","options":["石灰添加量与pH","浮选机叶轮磨损","给矿浓度是否偏低","精矿刮板转速"],"answer":[0],"explanation":"知识点：铜硫分离石灰抑制。石灰量不足或pH偏低时黄铁矿抑制不完全，硫精矿含铜升高；叶轮磨损影响充气但非首选；浓度偏低、刮板转速影响流程稳定但不直接导致该指标。"},{"id":222,"type":"single","stem":"现场磁选作业中精矿品位达标但尾矿磁性铁偏高，较合理的调整是","options":["增大磁选机筒体转速","减小磁选机给矿量","降低磁选机冲洗水量","增大磁系偏角"],"answer":[1],"explanation":"知识点：磁选回收率调整。尾矿磁性铁高说明磁性铁损失，减小给矿量可延长分选时间提高回收；增大转速会甩掉更多磁性铁使损失加大；降低冲洗水影响品位；增大偏角影响精矿排出。"},{"id":223,"type":"single","stem":"浮选流程中粗选泡沫发脆、易破裂且精矿品位偏低，最可能的原因是","options":["起泡剂用量不足","捕收剂用量不足","矿浆温度偏低","浮选机充气量偏小"],"answer":[0],"explanation":"知识点：起泡剂作用与泡沫状态。起泡剂不足泡沫脆易破、稳定性差；捕收剂不足泡沫量少但未必发脆；温度偏低泡沫黏度变化不同于发脆；充气量小泡沫量少但结构不必然发脆。"},{"id":224,"type":"single","stem":"球磨机运行中突然出现筒体螺栓漏浆，正确的处置是","options":["立即停机紧固或更换螺栓","继续运行待检修时处理","降低给矿量维持生产","向漏浆处塞入棉纱应急"],"answer":[0],"explanation":"知识点：磨机筒体螺栓漏浆处置。漏浆说明密封失效，继续运行会扩大泄漏甚至螺栓断裂，必须停机处理；降给矿、塞棉纱都是带病运行，不能消除隐患。"},{"id":225,"type":"single","stem":"颚式破碎机运行中突然出现排矿口堵塞、飞轮转速明显下降，此时首先应当采取的措施是","options":["立即停止给矿并切断主电机电源","加大给矿量把堵塞物料顶出去","打开排矿口调整装置让物料自行落下","关闭冷却水等待设备自然恢复"],"answer":[0],"explanation":"知识点是颚破堵塞的应急处置。堵塞时主机负荷剧增，必须先停给矿再停机，防止过载烧电机或损坏偏心轴。加大给矿量会进一步加剧过载；运行中打开排矿口调整装置在带载情况下易损坏调整机构；关闭冷却水与解除堵塞无关，也不解决过载。"},{"id":226,"type":"single","stem":"球磨机在正常给矿条件下出现返砂量明显增大、分级机溢流变粗，最可能的原因是","options":["磨机给矿量突然增大","分级机溢流堰高度被降低","磨机排矿浓度过低","分级机主轴转速提高"],"answer":[1],"explanation":"知识点是闭路磨矿中分级返砂与溢流粒度的关系。溢流堰降低会使沉砂更易返回，返砂量增大且溢流变粗。给矿量增大通常使返砂量也变化但需具体分析，不是首选对应；排矿浓度过低会加剧过磨，返砂一般不会因此明显增大；主轴转速提高会加强分级，返砂减少、溢流变细。"},{"id":227,"type":"single","stem":"浮选作业中，当矿浆pH值偏低导致黄药捕收作用减弱时，通常优先加入的调整剂是","options":["石灰","硫酸铜","松醇油","硫化钠"],"answer":[0],"explanation":"知识点是浮选pH调整剂的作用。石灰是常用碱性调整剂，可提高矿浆pH以增强黄药在硫化矿表面的吸附。硫酸铜是活化剂，不调pH；松醇油是起泡剂；硫化钠多用于硫化矿的抑制或硫化作用，不是提pH的首选。"},{"id":228,"type":"single","stem":"磁选机分选效果变差，精矿品位下降且尾矿磁性铁损失增加，检查发现给矿粒度比正常偏粗，此时合理的调整方向是","options":["提高磁选机滚筒转速","增大给矿量以提高处理能力","减小磁选机磁场强度","降低冲洗水量以减少矿浆扰动"],"answer":[3],"explanation":"知识点是磁选给矿粒度与分选效果的关系。粒度偏粗时，单体解离不充分，夹杂和连生体增多，应加强冲洗以减少机械夹杂，提高精矿品位。提高滚筒转速主要用于提高处理能力而非解决粒度问题；增大给矿量会加剧分选恶化；减小磁场强度会使磁性铁损失更大。"},{"id":229,"type":"single","stem":"棒磨机与球磨机相比，在选矿厂中常用于第一段磨矿的突出特点是","options":["产品粒度更细更均匀","对矿石的过粉碎较轻","单位处理量比球磨机大","磨矿介质消耗更低"],"answer":[1],"explanation":"知识点是棒磨与球磨的工艺差异。棒磨以线接触为主，对矿石过粉碎较轻，产品粒度较均匀，常用于第一段粗磨。产品更细是球磨特点；单位处理量棒磨一般低于球磨；棒磨介质消耗通常不低，故不选。"},{"id":230,"type":"single","stem":"某选矿厂浮选精矿泡沫发脆、易破裂，且精矿品位偏低，最可能缺少的药剂是","options":["起泡剂","捕收剂","活化剂","抑制剂"],"answer":[0],"explanation":"知识点是起泡剂对泡沫稳定性的影响。泡沫发脆易破说明泡沫稳定性不足，应补充起泡剂。捕收剂不足主要表现为回收率低而非泡沫发脆；活化剂影响矿物可浮性；抑制剂会降低目标矿物上浮，与泡沫发脆无直接对应。"},{"id":231,"type":"single","stem":"一段闭路磨矿中，分级机溢流浓度突然变稀而细度变粗，最先应检查的环节是","options":["磨机给矿水量","分级机溢流堰是否磨损","浮选药剂添加量","磁选机冲洗水量"],"answer":[1],"explanation":"知识点是分级机溢流异常的原因排查。溢流堰磨损或破损会使粗粒直接进入溢流，导致浓度变稀、细度变粗。给矿水量影响磨矿浓度但一般不会同时造成溢流变稀又变粗；浮选药剂和磁选冲洗水属于后续作业，不影响分级溢流。"},{"id":232,"type":"single","stem":"硫化铅锌矿浮选中，为抑制闪锌矿并优先浮选方铅矿，常用的抑制剂是","options":["硫酸锌","硫酸铜","丁基黄药","二号油"],"answer":[0],"explanation":"知识点是铅锌分离的抑制剂选择。硫酸锌是闪锌矿的常用抑制剂，常与石灰等配合实现铅锌优先浮选。硫酸铜是闪锌矿活化剂；丁基黄药是捕收剂；二号油是起泡剂，均无抑制作用。"},{"id":233,"type":"single","stem":"磁选作业中，若给矿中混有大量非磁性粗粒脉石，对分选过程最直接的影响是","options":["磁选机磁场强度自动升高","磁性精矿品位下降且易堵塞","精矿水分显著降低","磁选机滚筒转速自动加快"],"answer":[1],"explanation":"知识点是磁选给矿性质对分选的影响。非磁性粗粒脉石会机械夹杂进入精矿，降低品位，并可能在分选间隙造成堵塞。磁场强度、滚筒转速不会因给矿变化自动升高或加快；精矿水分一般不会因此显著降低。"},{"id":234,"type":"single","stem":"某选矿厂处理磁铁矿，要求最终精矿铁品位达到65%以上，现有流程为一段粗碎、一段磨矿加磁选，精矿品位仅60%，下一步最合理的改进方向是","options":["增加一段细碎或二段磨矿再选","提高磁选机给矿量","降低磁选机滚筒转速","减少磁选机冲洗水量"],"answer":[0],"explanation":"知识点是磁铁矿提精的流程优化。精矿品位不足多因单体解离不够，应增加细碎或二段磨矿并再选以进一步解离和抛尾。提高给矿量会恶化分选；降低滚筒转速和减少冲洗水都不利于提高精矿品位。"},{"id":235,"type":"single","stem":"颚式破碎机给料时，物料块度超过给料口宽度的多少比例就容易被卡住并降低生产能力","options":["0.5","0.7","0.85","0.95"],"answer":[2],"explanation":"颚式破碎机给料最大块度一般不超过给料口宽度的0.85，超过后易卡料、产量下降。0.5过小，不是卡料界限；0.7偏小，未达卡料风险区；0.95已明显超过允许上限。"},{"id":236,"type":"single","stem":"圆锥破碎机在正常碎矿时出现排矿口忽大忽小、机体有周期性振动，最可能的原因是","options":["给矿含水偏高","衬板磨损不均匀","偏心套间隙偏小","润滑油脂黏度偏低"],"answer":[1],"explanation":"衬板磨损不均匀会破坏破碎腔平行带，使排矿口周期性变化并引起振动。给矿含水偏高主要造成堵塞；偏心套间隙偏小多引起发热或闷车；润滑脂黏度偏低影响润滑而非排矿口尺寸。"},{"id":237,"type":"single","stem":"磨矿机运转中给矿量不变而返砂量明显增大，同时溢流细度变粗，应优先检查","options":["分级机溢流堰高度","磨矿浓度是否偏低","钢球装入量是否偏少","给矿粒度是否变细"],"answer":[1],"explanation":"磨矿浓度偏低会使矿浆流速快、物料来不及被磨细就进入分级，返砂增大且溢流变粗。溢流堰偏高会使溢流变粗但返砂不一定同步增大；钢球偏少通常使磨矿产品变粗且返砂增大不如浓度影响直接；给矿变细一般使返砂减少。"},{"id":238,"type":"single","stem":"球磨机启动前必须先做的一项操作是","options":["打开排矿端人孔盖","盘车检查筒体是否灵活","向筒体内加满钢球","关闭所有冷却水阀门"],"answer":[1],"explanation":"启动前盘车可确认筒体无卡阻、螺栓无松动，避免带负荷启动损坏设备。打开人孔盖不能代替盘车且启动前应关闭；加满钢球会增大启动负荷；关闭冷却水会使轴承无法散热。"},{"id":239,"type":"single","stem":"浮选作业中抑制剂的主要作用是","options":["提高目的矿物表面疏水性","降低脉石矿物表面疏水性","增加矿浆中气泡数量","加快矿粒沉降速度"],"answer":[1],"explanation":"抑制剂通过吸附在脉石矿物表面使其亲水，从而抑制其上浮。提高疏水性是捕收剂作用；增加气泡数量是起泡剂或充气作用；加快沉降是絮凝或重力沉降范畴。"},{"id":240,"type":"single","stem":"某选矿厂一段磨矿分级溢流突然跑粗，现场检查给矿量、给水量、返砂量均正常，下一步应重点检查","options":["分级机螺旋叶片磨损情况","磨矿机衬板螺栓是否松动","原矿仓给料粒度组成","浮选药剂添加量"],"answer":[0],"explanation":"给矿、给水、返砂正常而溢流跑粗，多因分级机螺旋叶片磨损使返砂提升能力下降、细粒来不及分级就溢流。衬板螺栓松动主要引起漏浆和振动；原矿粒度变化应反映在给矿量或返砂上；药剂添加量与磨矿分级无关。"},{"id":241,"type":"single","stem":"浮选流程中粗选作业的主要任务是","options":["提高最终精矿品位","丢弃大量合格尾矿","最大限度回收目的矿物","对精矿进行再磨"],"answer":[2],"explanation":"粗选在较大药剂用量和较粗条件下优先保证回收率，最大限度把目的矿物选入粗精矿。提高最终品位是精选任务；丢弃合格尾矿是扫选任务；再磨属于中矿处理环节。"},{"id":242,"type":"single","stem":"某班在球磨机运转中听到筒体内有清脆的金属撞击声且电流表指针周期性摆动，正确的处置是","options":["立即加大给矿量压住响声","停磨检查筒体衬板螺栓","继续运行并加强润滑","打开排矿口降低负荷"],"answer":[1],"explanation":"清脆金属撞击声伴电流摆动，多因衬板螺栓松动或衬板脱落，必须停磨检查。加大给矿会加剧损坏；继续运行可能造成筒体损伤；打开排矿口不能消除撞击源。"},{"id":243,"type":"multi","stem":"浮选过程中影响泡沫层稳定性的操作因素包括","options":["充气量大小","起泡剂添加量","矿浆温度","刮板转速","给矿粒度组成"],"answer":[0,1,2],"explanation":"充气量、起泡剂用量和矿浆温度都直接影响泡沫层厚度与稳定性。刮板转速影响刮出量而不决定泡沫层稳定性；给矿粒度组成影响可选性，不是泡沫层稳定性的直接操作因素。"},{"id":244,"type":"single","stem":"颚式破碎机给矿时，给矿块度超过给矿口宽度的多少比例就容易发生卡矿，因此通常要控制给矿最大块度不超过给矿口宽度的0.85倍？","options":["0.6倍","0.75倍","0.85倍","1.0倍"],"answer":[2],"explanation":"知识点为颚式破碎机给矿块度控制。给矿最大块度一般不超过给矿口宽度的0.85倍，过大易卡矿、降低处理量。0.6倍偏保守但并非通常上限；0.75倍低于常规控制值；1.0倍与给矿口等宽必然卡矿。"},{"id":245,"type":"single","stem":"圆锥破碎机采用挤满给矿时，与常规给矿相比，其破碎产品粒度分布的主要变化是？","options":["粒级更均匀且细粒增多","粒级更宽且粗粒增多","中间粒级明显减少","粗细两端同时减少"],"answer":[0],"explanation":"知识点为圆锥破碎机挤满给矿效果。挤满给矿使破碎腔充满物料，层压破碎增强，产品更均匀、细粒增多。粒级更宽且粗粒增多与层压破碎效果相反；中间粒级明显减少不符合层压破碎特征；粗细两端同时减少无依据。"},{"id":246,"type":"single","stem":"球磨机磨矿过程中出现“胀肚”现象，现场最先应采取的处置是？","options":["立即增加给矿量提高充填率","减少或停止给矿并适当加大排矿水","降低磨机转速至最低","关闭排矿口提高矿浆浓度"],"answer":[1],"explanation":"知识点为磨机胀肚处置。胀肚是磨机内物料过多、排料不畅，应先减少或停止给矿、加大排矿水以疏通。增加给矿会加剧胀肚；降低转速不能解决排料不畅；关闭排矿口会使矿浆更浓、加剧胀肚。"},{"id":247,"type":"single","stem":"浮选作业中，矿浆pH值升高时，通常对黄药类捕收剂浮选硫化矿的影响是？","options":["捕收能力增强，用量减少","捕收能力减弱，用量可能增大","对捕收能力无影响","只影响起泡剂用量"],"answer":[1],"explanation":"知识点为pH对黄药捕收的影响。pH升高会抑制黄药在硫化矿表面的吸附，捕收能力减弱，需增大用量。捕收能力增强与碱性抑制相反；无影响不符合实际；pH主要影响捕收剂而非仅起泡剂。"},{"id":248,"type":"single","stem":"浮选机刮泡时发现泡沫层过厚、发黏且精矿品位下降，较合理的调整方向是？","options":["增加捕收剂用量强化刮泡","适当减少起泡剂或加大冲洗水","提高矿浆浓度至最高","降低浮选机充气量至最小"],"answer":[1],"explanation":"知识点为浮选泡沫层异常调整。泡沫过厚发黏、品位下降常因起泡剂过量或泡沫夹带脉石，应减少起泡剂或加冲洗水。增加捕收剂会加重夹带；提高浓度至最高会恶化分选；充气量降至最小会使泡沫层更不稳而非解决夹带。"},{"id":249,"type":"single","stem":"磁选机分选弱磁性矿物时，为提高回收率，通常采取的措施是？","options":["降低磁场强度减少夹杂","提高磁场强度并减小矿浆流速","增大矿浆流速缩短分选时间","减小磁极间隙降低处理量"],"answer":[1],"explanation":"知识点为弱磁性矿物磁选。弱磁性矿物需较高磁场强度和较慢流速以保证吸附。降低磁场强度会降低回收；增大流速使磁性颗粒来不及吸附；减小磁极间隙虽提高场强但降低处理量并非提高回收率的常规措施。"},{"id":250,"type":"single","stem":"摇床选矿时，床面上物料按密度分带，精矿通常位于床面的哪个区域？","options":["给矿端靠近传动端","精矿端沿纵向最远端","尾矿侧横向边缘","床面中央无分带区"],"answer":[0],"explanation":"知识点为摇床分带规律。重矿物受差动运动向精矿端（给矿端靠近传动端一侧）富集。精矿端最远端、尾矿侧横向边缘均为轻矿物或尾矿去向；中央无分带区不符合摇床分带实际。"},{"id":251,"type":"single","stem":"分级机与磨机组成闭路磨矿时，返砂量突然增大，较可能的原因是？","options":["磨机给矿量突然减少","分级机溢流粒度变粗","磨机排矿水突然加大","分级机螺旋提升速度调快"],"answer":[1],"explanation":"知识点为闭路磨矿返砂变化。返砂增大常因分级溢流变粗、合格粒级减少，返回再磨量增加。给矿量减少会使返砂减少；排矿水加大使矿浆变稀、返砂可能减少；螺旋提升速度调快会提高返砂输送能力但不改变返砂量成因。"},{"id":252,"type":"single","stem":"浮选药剂中，松醇油在浮选过程中的主要作用是？","options":["提高矿物表面疏水性","稳定泡沫并调节泡沫结构","抑制脉石矿物上浮","调节矿浆酸碱度"],"answer":[1],"explanation":"知识点为浮选起泡剂作用。松醇油是常用起泡剂，主要稳定泡沫、调节泡沫结构。提高疏水性是捕收剂作用；抑制脉石是抑制剂作用；调节pH是pH调整剂作用。"},{"id":253,"type":"single","stem":"重介质选矿中，介质悬浮液密度低于分选密度时，会导致？","options":["轻矿物进入重产物","重矿物进入轻产物","分选精度提高","介质黏度下降"],"answer":[1],"explanation":"知识点为重介质分选密度控制。悬浮液密度偏低时，部分重矿物无法下沉而进入轻产物，降低重产物回收。轻矿物进入重产物是密度偏高时的现象；分选精度提高与密度偏低无关；介质黏度主要受介质性质影响。"},{"id":254,"type":"single","stem":"选矿厂破碎作业中，颚式破碎机给矿最大块度一般不应超过给矿口宽度的多少","options":["0.5","0.85","0.65","0.95"],"answer":[1],"explanation":"知识点为颚式破碎机给矿粒度控制。正确项0.85符合常见操作要求（给矿块度不超过给矿口宽度的0.85）。错项0.5过小会限制处理量；错项0.65偏小同样浪费破碎能力；错项0.95过大易造成卡料和衬板损坏。"},{"id":255,"type":"single","stem":"磨矿作业中，磨机排矿浓度突然升高且分级机返砂量增大，最可能的原因是","options":["给矿量减少","给水量减少","磨机转速提高","钢球补加量增加"],"answer":[1],"explanation":"知识点为磨矿浓度与分级返砂的关系。给水量减少使磨矿浓度升高、矿浆黏度增大，分级返砂量随之增加。给矿量减少会使浓度降低；磨机转速提高主要改变磨矿效率；钢球补加量增加不直接导致浓度突升。"},{"id":256,"type":"single","stem":"磁选过程中，提高磁选机磁场强度后精矿品位反而下降，最可能的原因是","options":["磁性颗粒回收率提高","脉石连生体被夹带选出","矿浆流速降低","磁系转速下降"],"answer":[1],"explanation":"知识点为磁选选择性与磁场强度关系。磁场过强会把磁性较弱的连生体和脉石夹带选出，降低精矿品位。回收率提高不等于品位提高；矿浆流速降低和磁系转速下降不是品位下降的直接主因。"},{"id":257,"type":"single","stem":"浮选机运行中泡沫层变薄、泡沫发脆且精矿品位偏高但回收率下降，最可能的原因是","options":["捕收剂用量不足","起泡剂用量过大","抑制剂用量不足","矿浆温度过低"],"answer":[0],"explanation":"知识点为浮选药剂制度判断。捕收剂不足使矿物表面疏水性下降，泡沫变薄发脆、回收率降低。起泡剂过量会使泡沫过多而非发脆；抑制剂不足会使脉石上浮、品位下降；矿浆温度过低影响整体浮选速度而非仅此现象。"},{"id":258,"type":"single","stem":"一段闭路磨矿中，分级机溢流粒度变粗且返砂量减少，优先应检查的是","options":["磨机给矿量是否减小","分级机主轴转速是否降低","磨机排矿是否堵塞","补加水是否过量"],"answer":[1],"explanation":"知识点为闭路磨矿分级控制。分级机主轴转速降低使分级效率下降、溢流变粗且返砂减少。给矿量减小通常使溢流变细；排矿堵塞会使返砂异常；补加水过量使浓度降低、溢流变细。"},{"id":259,"type":"single","stem":"浮选作业中矿浆充气量过大时，最可能出现的现象是","options":["泡沫层稳定且品位提高","泡沫兼并加快、精矿品位下降","矿浆pH值自动升高","捕收剂用量自动减少"],"answer":[1],"explanation":"知识点为浮选充气量与泡沫状态。充气量过大使泡沫兼并加快、脉石夹带增多，精矿品位下降。充气量过大会破坏泡沫稳定性；pH值和捕收剂用量不会自动变化。"},{"id":260,"type":"single","stem":"弱磁选机分选强磁性矿物时，给矿浓度过高对分选效果的主要影响是","options":["磁性颗粒易被冲走","矿浆黏度增大导致夹杂","磁场强度自动增强","磁系温度升高"],"answer":[1],"explanation":"知识点为磁选给矿浓度影响。浓度过高使矿浆黏度增大，脉石夹杂严重，精矿品位下降。磁性颗粒不易被冲走；磁场强度与浓度无关；磁系温度不由浓度决定。"},{"id":261,"type":"single","stem":"磨矿工在巡检时发现球磨机筒体局部温度异常升高并伴有规律性撞击声，正确处置是","options":["立即加大给矿量掩盖声音","停机检查筒体衬板及钢球","继续运行并记录温度变化","提高磨矿浓度降低撞击"],"answer":[1],"explanation":"知识点为磨机异常判断与处置。局部高温加规律撞击声提示衬板松动或钢球异常，应停机检查。加大给矿、继续运行、提高浓度都会延误处理并可能扩大设备损坏。"},{"id":262,"type":"multi","stem":"影响浮选过程选择性的因素中，下列属于矿浆性质调节范畴的是","options":["调整矿浆pH值","调节矿浆温度","改变捕收剂烃链长度","控制矿浆氧化还原电位","调整浮选机叶轮转速"],"answer":[0,1,3],"explanation":"知识点为浮选矿浆性质调节。pH值、温度、氧化还原电位均属矿浆性质调节。捕收剂烃链长度是药剂结构选择问题；叶轮转速属浮选机操作参数，不属矿浆性质调节。"},{"id":263,"type":"single","stem":"选矿厂破碎车间中，颚式破碎机排矿口尺寸的调整通常通过增减垫片来实现，垫片厚度变化对排矿口的影响是","options":["垫片增厚使排矿口减小","垫片增厚使排矿口增大","垫片厚度变化不影响排矿口","垫片增厚使动颚行程增大"],"answer":[1],"explanation":"颚式破碎机通过调整垫片厚度改变动颚与定颚间的最小距离，即排矿口。垫片增厚会顶推动颚后退，使排矿口增大，故B正确；A方向相反；C忽略机械结构；D混淆了垫片与偏心轴行程的作用。"},{"id":264,"type":"single","stem":"磨矿分级回路中，返砂量突然增大且溢流粒度变粗，在给矿量和给水量未变的情况下，最可能的原因是","options":["分级机溢流堰升高","磨机给矿中细粒级增多","分级机主轴转速降低","磨机排矿中粗粒级增多"],"answer":[2],"explanation":"分级机主轴转速降低使返砂提升能力下降，细粒来不及溢流而随返砂返回，导致返砂量增大、溢流变粗，故C正确；A溢流堰升高会使溢流变细；B细粒增多应使返砂减少；D粗粒增多会增大返砂但溢流不会必然变粗到该程度。"},{"id":265,"type":"single","stem":"浮选作业中，矿浆pH值对捕收剂作用效果影响显著，用黄药捕收硫化铜矿时，通常将矿浆pH控制在","options":["酸性范围以增强黄药活性","中性范围以抑制脉石","弱碱性范围以兼顾选择性和回收率","强碱性范围以完全抑制硫化矿"],"answer":[2],"explanation":"黄药浮选硫化铜矿常用弱碱性（约pH 8~10）兼顾捕收效果与脉石抑制，故C正确；A酸性会腐蚀设备且选择性差；B中性对脉石抑制不足；D强碱性会抑制硫化铜矿本身。"},{"id":266,"type":"single","stem":"磁选机分选过程中，给矿粒度对分选效果影响很大，弱磁性矿物采用高梯度磁选时，给矿粒度一般应控制在","options":["0.5mm以下且尽量细磨","2mm左右以保持处理量","5mm左右以减少泥化","10mm左右以利磁团聚"],"answer":[0],"explanation":"高梯度磁选用于弱磁性细粒矿物，给矿需细磨至0.5mm以下使矿物单体解离，故A正确；B、C、D粒度过粗时磁性颗粒所受磁力不足，难以有效捕获。"},{"id":267,"type":"single","stem":"某选矿厂球磨机运转中突然出现筒体振动加剧、声音异常沉闷，最可能的原因是","options":["磨机给矿量偏少","磨机内钢球装量不足","磨机内矿浆浓度过高","磨机衬板螺栓松动或脱落"],"answer":[3],"explanation":"筒体振动加剧伴异常沉闷声多为衬板螺栓松动或衬板脱落导致，故D正确；A给矿少声音偏响；B钢球少磨矿效率低但振动不明显；C浓度高主要影响磨矿效果和排矿。"},{"id":268,"type":"single","stem":"浮选机刮泡量突然减少，但泡沫层厚度正常、矿浆面稳定，检查发现充气量也未变，此时应优先检查","options":["刮板转速是否下降","矿浆温度是否升高","捕收剂添加量是否偏少","泡沫槽是否堵塞"],"answer":[0],"explanation":"泡沫层和液面正常说明浮选过程未恶化，刮泡量减少最可能是刮板转速下降或传动故障，故A正确；B温度升高通常影响浮选选择性；C捕收剂少会使泡沫层变薄；D泡沫槽堵塞会导致泡沫外溢而非刮泡量减少。"},{"id":269,"type":"single","stem":"选矿厂浓密机溢流中出现大量细粒固体，底流浓度却偏低，最可能的原因是","options":["给矿量突然减小","絮凝剂添加量不足","底流泵转速过高","浓密机耙架转速过快"],"answer":[1],"explanation":"絮凝剂不足使细粒无法有效团聚沉降，随溢流跑出且底流浓度低，故B正确；A给矿减少应使溢流更清；C底流泵快会提高底流浓度降低溢流浊度；D耙架转速影响不大。"},{"id":270,"type":"single","stem":"在浮选流程中，中矿返回地点选择的主要依据是","options":["中矿的品位和连生体含量","中矿的矿浆温度","中矿的pH值高低","中矿的泡沫颜色"],"answer":[0],"explanation":"中矿返回地点取决于其中有用矿物品位和连生体解离程度，品位接近精矿可返回精选，接近原矿则返回粗选，故A正确；B、C、D不是决定返回地点的核心因素。"},{"id":271,"type":"single","stem":"磁选过程中，为了提高磁性矿物的回收率，对给矿进行预先脱泥的主要目的是","options":["减少矿浆体积提高处理量","去除细泥对磁性颗粒的包裹和干扰","降低给矿品位以利分选","提高磁选机磁场强度"],"answer":[1],"explanation":"细泥会包裹磁性颗粒并随水流带走，脱泥可减少干扰提高回收率，故B正确；A是附带效果非主要目的；C脱泥反而可能提高品位；D脱泥不改变磁场强度。"},{"id":272,"type":"single","stem":"某选矿厂磨矿分级回路中，旋流器溢流粒度突然变粗，沉砂量增大，在给矿压力不变的情况下，最可能的原因是","options":["旋流器给矿浓度降低","旋流器沉砂口磨损增大","旋流器溢流管直径减小","旋流器锥体磨损减薄"],"answer":[1],"explanation":"沉砂口磨损增大使沉砂排出量增加、溢流变粗，故B正确；A浓度降低会使溢流变细；C溢流管减小使溢流变细；D锥体磨损主要影响分级效率而非直接使溢流变粗。"},{"id":273,"type":"single","stem":"颚式破碎机工作时，给料块度超过给料口宽度的多少倍时最容易发生卡料和返料","options":["0.85倍","0.95倍","1.05倍","1.15倍"],"answer":[0],"explanation":"颚破给料最大块度一般不超过给料口宽度的0.85倍，超过后物料难以被咬入，易卡料和返料；0.95倍已接近给料口宽度，仍偏大；1.05倍和1.15倍均超过给料口宽度，根本不能正常给入。"},{"id":274,"type":"single","stem":"圆锥破碎机采用挤满给矿方式运行时，给矿量应使破碎腔保持什么状态","options":["给矿均匀铺满动锥表面","给矿量略小于腔容避免过载","给矿量随电流波动随时调整","给矿量只覆盖定锥上部区域"],"answer":[0],"explanation":"挤满给矿要求矿料充满破碎腔并均匀分布在动锥周围，使层压破碎效果稳定；给矿量略小于腔容属于非挤满给矿，破碎比和产品粒形都变差；随电流波动随时调整是操作误区，会造成腔型忽空忽满；只覆盖定锥上部区域则下部无料层，失去层压作用。"},{"id":275,"type":"single","stem":"球磨机磨矿介质充填率是指磨机静止时介质堆积体积占磨机有效容积的百分比，现场常通过什么现象辅助判断充填率是否合适","options":["磨机电流和磨音的变化","排矿水量的瞬时波动","分级机返砂的粒度组成","给矿皮带上的矿石湿度"],"answer":[0],"explanation":"充填率变化会直接影响磨机负荷，表现为电流和磨音改变，是现场最直接的判断依据；排矿水量波动主要与给水量和排矿口有关；返砂粒度反映分级效果而非充填率；矿石湿度影响给料和堵塞，不直接反映介质充填量。"},{"id":276,"type":"single","stem":"浮选机叶轮转速降低后，最可能出现的直接现象是","options":["矿浆充气量减少、气泡变大","精矿品位立即升高","泡沫层厚度自动增厚","药剂用量自动减少"],"answer":[0],"explanation":"叶轮转速降低使矿浆循环和吸气能力下降，充气量减少、气泡尺寸变大，浮选效果变差；精矿品位不会因转速降低而自动升高；泡沫层厚度受充气和药剂共同影响，不会自动增厚；药剂用量需人工调整，不会自动减少。"},{"id":277,"type":"single","stem":"浮选作业中，矿浆pH值对捕收剂作用效果影响很大，用黄药浮选硫化铜矿时通常将pH控制在什么范围","options":["8～10","3～5","11～13","1～2"],"answer":[0],"explanation":"黄药浮选硫化铜矿常用pH 8～10，此时捕收剂效果较好且能抑制部分脉石；pH 3～5偏酸，设备腐蚀且黄药易分解；pH 11～13偏高，会抑制铜矿物上浮；pH 1～2强酸条件不适合常规硫化铜浮选。"},{"id":278,"type":"single","stem":"一段磨矿与螺旋分级机构成闭路时，返砂量过大最可能的原因是","options":["磨机排矿粒度过粗","分级机溢流浓度过低","给矿量突然减少","磨机转速偏高"],"answer":[0],"explanation":"闭路磨矿中返砂量过大通常说明分级机溢流跑粗、磨机排矿粒度偏粗，合格粒级少；溢流浓度过低时返砂量可能偏小；给矿量减少会使返砂量下降；磨机转速偏高反而有利于磨细，不会直接导致返砂量过大。"},{"id":279,"type":"single","stem":"浮选泡沫层过厚且发黏、精矿品位下降，优先应检查的是","options":["起泡剂用量是否偏大","捕收剂用量是否偏小","磨矿细度是否偏细","给矿品位是否偏高"],"answer":[0],"explanation":"泡沫层过厚发黏多与起泡剂过量有关，泡沫稳定性过强会把脉石机械夹带上来，降低精矿品位；捕收剂偏小会使泡沫变脆、上浮量减少；磨矿偏细会使矿泥增多，但泡沫发黏的直接原因仍以起泡剂为主；给矿品位偏高不会使泡沫发黏。"},{"id":280,"type":"single","stem":"某选厂磁选作业精矿品位偏低，检查发现磁选机滚筒转速过快，正确的调整方向是","options":["适当降低滚筒转速","继续提高滚筒转速","加大给矿水量","减小磁系偏角"],"answer":[0],"explanation":"滚筒转速过快使磁性颗粒在磁场区停留时间不足，非磁性夹杂来不及脱落，精矿品位下降，应适当降低转速；继续提高转速会加剧问题；加大给矿水量主要影响浓度和冲洗，不是首要措施；减小磁系偏角会改变磁翻滚次数，调整方向不直接针对转速过快。"},{"id":281,"type":"single","stem":"选厂浮选流程中，中矿返回地点选择不当最容易造成的后果是","options":["有用矿物在回路中循环积累","精矿品位一次性提高","尾矿品位立即降低","药剂用量自动减少"],"answer":[0],"explanation":"中矿返回地点不当会使连生体在回路中反复循环、有用矿物积累，影响回收率和流程稳定；精矿品位不会一次性提高；尾矿品位不会立即降低；药剂用量也不会自动减少。"},{"id":282,"type":"single","stem":"夜班运行时球磨机突然出现声音沉闷、电流升高且排矿量减少，正确的下一步处置是","options":["立即减少给矿量并检查是否胀肚","立即加大给矿量提高处理能力","立即停水停料等待自然恢复","立即提高分级机转速加大返砂"],"answer":[0],"explanation":"声音沉闷、电流升高、排矿减少是磨机胀肚的典型征兆，应立即减少给矿量并检查处理；加大给矿量会加重胀肚；停水停料等待可能造成磨机堵塞和设备损坏；提高分级机转速不能解决磨机内物料积压问题。"},{"id":283,"type":"single","stem":"选矿厂破碎作业中，颚式破碎机给料最大块度一般不宜超过给料口宽度的多少","options":["0.5倍","0.85倍","1.2倍","1.5倍"],"answer":[1],"explanation":"知识点是颚式破碎机给料粒度控制。给料块度过大易卡料、跳料并损坏颚板，通常控制在给料口宽度的0.85倍左右；0.5倍偏保守但不会卡料，属安全做法而非规定上限；1.2倍和1.5倍均超过给料口宽度，会造成堵料和设备损伤。"},{"id":284,"type":"single","stem":"磨矿分级回路中，旋流器溢流浓度突然升高、溢流中粗粒明显增多，最先应检查的运行参数是","options":["旋流器给矿压力是否偏低","磨机排矿水量是否偏大","旋流器沉砂嘴是否磨损扩大","分级机大耙转速是否过快"],"answer":[0],"explanation":"知识点是旋流器分级异常判断。给矿压力偏低会使离心力不足、分级粒度变粗、粗粒进入溢流，故先查压力；排矿水量偏大会稀释矿浆、反而使溢流变细；沉砂嘴磨损扩大主要使沉砂浓度下降、易跑粗但通常伴随沉砂量增大，不是首要检查项；大耙转速与旋流器分级粒度无直接对应关系。"},{"id":285,"type":"single","stem":"磁选机分选效果变差，精矿品位下降而尾矿磁性铁升高，下列原因中最可能是","options":["磁选机滚筒转速过低","给矿浓度过低","磁系偏角调整过大","磁选机给矿量偏小"],"answer":[0],"explanation":"知识点是磁选机操作参数影响。滚筒转速过低使矿粒在磁场中停留时间过长、夹杂脉石增多，精矿品位下降且磁性铁易随尾矿流失；给矿浓度过低和给矿量偏小通常有利于分选，不会造成尾矿磁性铁升高；磁系偏角过大主要影响精矿排出位置，不是尾矿跑铁的主因。"},{"id":286,"type":"single","stem":"球磨机在运行中出现“胀肚”现象，下列处置措施中最合理的是","options":["立即加大给矿量提高处理能力","减少给矿量并适当增大排矿水","停磨后打开人孔清理钢球","提高分级机溢流浓度"],"answer":[1],"explanation":"知识点是磨机胀肚的判断与处理。胀肚是磨机内矿量过多、排矿不畅，应减少给矿并增大排矿水以尽快排出；加大给矿会加剧胀肚；停磨清球是严重堵磨后的处理手段，不是首选；提高溢流浓度会使分级返砂增多，进一步加重磨机负荷。"},{"id":287,"type":"single","stem":"浮选过程中发现精矿泡沫发脆、易破且上浮量减少，最可能的原因是","options":["起泡剂用量不足","捕收剂用量过多","矿浆温度过低","浮选机充气量过大"],"answer":[0],"explanation":"知识点是浮选药剂作用判断。起泡剂不足时泡沫脆、易破裂、携带能力差，精矿上浮量减少；捕收剂过多通常使泡沫黏、量大但选择性差；矿浆温度过低会整体减慢浮选速度，但泡沫不一定发脆；充气量过大会使泡沫翻动剧烈、易破，但通常伴随泡沫量增大。"},{"id":288,"type":"single","stem":"一段磨矿与二段磨矿相比，下列描述正确的是","options":["一段磨矿给矿粒度更细","一段磨矿通常与分级组成闭路","二段磨矿循环负荷一定小于一段","一段磨矿产品粒度一定达到最终要求"],"answer":[1],"explanation":"知识点是阶段磨矿流程。一段磨矿给矿粒度为破碎产品，通常较粗，且多与分级设备组成闭路；二段磨矿给矿是一段产品，循环负荷不一定小于一段；一段磨矿产品往往还需再磨，不一定达到最终解离粒度，故只有“一段磨矿通常与分级组成闭路”正确。"},{"id":289,"type":"single","stem":"磁选作业中，给矿浓度过高时对分选效果的主要影响是","options":["矿浆黏度增大，分选选择性变差","磁场强度显著增强，精矿品位提高","矿粒磁性增强，回收率提高","磁选机处理量自动增大"],"answer":[0],"explanation":"知识点是磁选给矿浓度的影响。给矿浓度过高使矿浆黏度增大、矿粒分散变差、夹杂增多，分选选择性下降；磁场强度由设备磁系决定，不随浓度变化；矿粒磁性是固有性质，不因浓度改变；处理量由设备能力决定，不会自动增大。"},{"id":290,"type":"single","stem":"破碎流程中，预先筛分与检查筛分的主要区别是","options":["预先筛分设在破碎机前，检查筛分设在破碎机后","预先筛分设在破碎机后，检查筛分设在破碎机前","两者都设在破碎机前，仅筛孔不同","两者都设在破碎机后，仅处理量不同"],"answer":[0],"explanation":"知识点是筛分作业在破碎流程中的位置。预先筛分在破碎机前筛出已合格细粒，避免过粉碎；检查筛分在破碎机后，控制破碎产品粒度并将不合格粗粒返回再碎；其余选项把两者位置颠倒或混为一谈。"},{"id":291,"type":"multi","stem":"某选矿厂浮选作业出现精矿品位偏低、泡沫夹带脉石增多，下列调整措施中合理的有","options":["适当降低捕收剂用量","适当增加抑制剂用量","适当提高浮选机充气量","适当延长浮选时间","适当提高矿浆浓度"],"answer":[0,1,3],"explanation":"知识点是浮选精矿品位偏低的调整。精矿品位偏低多因捕收剂过量、脉石抑制不足或浮选时间不够，故可降低捕收剂、增加抑制剂、适当延长浮选时间；提高充气量会加强机械夹带，使脉石更多进入泡沫；提高矿浆浓度也会加重夹带，均不利于提高品位。"},{"id":292,"type":"single","stem":"选矿厂中碎作业采用圆锥破碎机，当给矿粒度变粗且给矿量增大时，为保持产品粒度合格，最先应当调整的操作参数是","options":["适当减小排矿口尺寸","适当增大排矿口尺寸","提高偏心轴转速","增大给矿口宽度"],"answer":[0],"explanation":"知识点：圆锥破碎机排矿口与产品粒度的关系。给矿变粗、量增大时产品会变粗，缩小排矿口可直接限制产品最大粒度，故正确项对。增大排矿口会使产品更粗，与目标相反；偏心轴转速一般由设备固定或影响处理量和产品形状，不是调节粒度的首选；给矿口宽度由设备结构决定，不能作为调节手段。"},{"id":293,"type":"single","stem":"球磨机运行中出现“胀肚”现象，现场判断依据和首要处置措施是","options":["排矿量明显减少且声音沉闷，应适当减少给矿量","排矿量明显减少且声音清脆，应加大给矿量","排矿量增大且声音沉闷，应提高磨机转速","排矿量增大且声音清脆，应减少补加水量"],"answer":[0],"explanation":"知识点：磨机胀肚的判断与处置。胀肚时矿浆充满磨机、排矿减少、声音沉闷，首先应减给矿或停给矿，故正确项对。声音清脆通常是空磨或负荷偏轻的表现，与胀肚相反；增大给矿会加重胀肚；提高转速不能解决胀肚且可能加剧问题。"},{"id":294,"type":"single","stem":"浮选过程中发现精矿品位下降而回收率变化不大，且泡沫层变薄、泡沫发脆，最可能的原因是","options":["起泡剂用量不足","捕收剂用量不足","抑制剂用量不足","矿浆温度过高"],"answer":[0],"explanation":"知识点：浮选药剂作用与泡沫状态判断。泡沫层薄、泡沫发脆是起泡剂不足的典型表现，起泡剂不足会使泡沫不稳定、携带脉石增多导致品位下降，故正确项对。捕收剂不足主要使回收率下降、泡沫量减少；抑制剂不足会使脉石上浮、品位下降但泡沫一般不会明显变脆；矿浆温度过高会使药剂作用加快、泡沫状态改变但通常不会仅表现为泡沫发脆。"},{"id":295,"type":"single","stem":"磁选作业中，给矿粒度对磁选效果影响很大，下列做法正确的是","options":["入选前应尽量使矿物达到单体解离","入选前应尽量使矿物保持连生体状态","入选前应尽量增大矿粒粒度","入选前应尽量降低矿浆浓度至5%以下"],"answer":[0],"explanation":"知识点：磁选对给矿粒度的要求。磁选要求矿物充分单体解离，连生体会使磁性矿物与非磁性矿物混杂，降低分选效果，故正确项对。保持连生体会降低分选指标；增大粒度过大则磁性矿物与非磁性矿物连生体多、分选差；矿浆浓度过低会降低处理量且不一定提高分选效果。"},{"id":296,"type":"single","stem":"某选矿厂浮选作业中，粗选作业泡沫产品进入精选作业，精选尾矿返回粗选，这种流程属于","options":["开路流程","闭路流程","半闭路流程","分支流程"],"answer":[1],"explanation":"知识点：浮选流程结构。精选尾矿返回粗选形成循环，属于闭路流程，故正确项对。开路流程无返回产物；半闭路流程是部分产物返回；分支流程是不同分支处理不同产物，与本题描述不符。"},{"id":297,"type":"single","stem":"在选矿厂破碎流程中，筛分作业的主要作用是","options":["对矿石进行预先分级和检查分级","对矿石进行磨矿前的细磨","对矿石进行脱水处理","对矿石进行磁选预选"],"answer":[0],"explanation":"知识点：破碎流程中筛分的作用。筛分用于预先分级和检查分级，控制破碎产品粒度，故正确项对。磨矿由磨机完成；脱水由浓缩、过滤等作业完成；磁选预选由磁选设备完成，均非筛分作业功能。"},{"id":298,"type":"single","stem":"某选矿厂磨矿分级回路中，分级机返砂量突然增大，溢流粒度变粗，最可能的原因是","options":["磨机给矿量突然增大","分级机补加水量突然增大","磨机排矿浓度过低","分级机溢流堰高度降低"],"answer":[0],"explanation":"知识点：磨矿分级回路异常判断。给矿量增大使磨机负荷增加、排矿变粗，分级机返砂量增大、溢流变粗，故正确项对。补加水量增大会使溢流变细、返砂减少；排矿浓度过低通常使返砂减少；溢流堰降低会使溢流变粗但返砂量不一定突然增大。"},{"id":299,"type":"single","stem":"某选矿厂磁选作业中，磁选机精矿品位偏低，现场检查发现磁选机滚筒表面有较多非磁性矿物粘附，下列处置最合理的是","options":["适当增大磁选机滚筒转速","适当减小磁选机滚筒转速","适当增大给矿量","适当提高矿浆浓度"],"answer":[0],"explanation":"知识点：磁选机操作参数对分选效果的影响。滚筒表面粘附非磁性矿物说明分选不充分，适当提高转速可增强离心力、减少非磁性矿物夹带，故正确项对。减小转速会加重夹带；增大给矿量会加大分选负荷；提高矿浆浓度会降低分选选择性，均不合理。"},{"id":300,"type":"multi","stem":"某铜硫矿浮选班在粗选作业中发现精矿泡沫发黏、尾矿跑铜升高，现场需同时调整下列哪些操作来稳定浮选指标","options":["适当降低抑制剂石灰用量并补加少量硫化钠","保持现有捕收剂用量不变而只加大起泡剂","将粗选充气量适当调大并检查泡沫刮出量","把磨矿分级溢流细度从65%调至75%再观察"],"answer":[2,3],"explanation":"本题考查浮选泡沫异常与流程条件的综合判断：泡沫发黏且尾矿跑铜高，常见原因是矿泥多、细度偏粗或充气刮泡不足。调大充气量并核对刮出量能改善泡沫层流动性，提高回收；把溢流细度适当提高有助于单体解离、减少连生体跑尾。A项错在降低石灰用量会削弱对黄铁矿的抑制，还可能使铜硫分离恶化；B项错在只加起泡剂会加剧泡沫发黏而不解决回收问题。"}]}