四川某选厂球磨分级自动控制系统

为四川某矿业集团选矿厂设计了球磨分级自动控制系统。在一段球磨分级过程中,通过检测球磨机负荷和螺旋分级机的溢流浓度,采用串级PID控制,实现对新给矿量和溢流浓度的控制,从而间接控制磨矿浓度和螺旋分级机的溢流粒度。在二段磨矿的旋流器给矿泵池,使用超声波液位计和核子密度计分别检测泵池液位和矿浆浓度,并对其进行控制,使旋流器有较好的工况。同时用计算机进行实时监控,显示各重要数据和设备状态及报警等。详细说明了各参数的控制方案和整体设计思路。     

Application of model predictive control in ball mill grinding circuit

Grinding circuit needs to be stably controlled for high recovery rate of mineral ore and significant reduction of production cost in concentrator plants. Ball mill grinding circuit is essentially a multi-input–multi-output (MIMO) system with strong coupling among process variables. Simplified model with multi-loop decoupled PID control usually cannot maintain a long-time stable control in real practice. The response tests between four controlled variables (namely, product particle size, mill solids concentration, sump level and circulating load) and four manipulated variables (namely, fresh ore feed rate, mill feed water flow rate, pump speed and dilution water flow rate) are carried out to construct a four-input–four-output model of grinding circuit. Based on this modeling, constrained model predictive control (MPC) is adopted to handle such strong coupling system and evaluated in an iron ore concentrator plant. The variables are controlled around their set-points and a long-term stable operation of the grinding circuit close to their optimum operating conditions is achieved. More than three years’ operation in industry demonstrates the effectiveness and practicality of this control strategy.     

The interaction of flash flotation with closed circuit grinding

Flash flotation is an important unit operation within many grinding circuits. It provides an opportunity for the valuable mineral to be recovered as early as possible in the processing plant. This prevents liberated valuable mineral from building up in the recirculating load of the mill, and reduces the occurrence of overgrinding. Overgrinding can place a significant limitation on overall recovery, because it causes the production of valuable fines that are difficult to recover by flotation.The flash flotation cell is fed by the cyclone underflow in a closed grinding circuit. This feed stream represents the optimal particle size distributions of valuable mineral and gangue for flotation kinetics, selectivity and grade. The flash cell treats the recirculating load of the ball mill, and therefore influences the performance of both the mill and the hydrocyclone classifier. The effect of a flash cell in the grinding circuit is difficult to determine since flash cells in Australia are introduced at the design stage and so no plant data is available before and after the introduction of the flash flotation unit. By establishing a computer simulation of the closed-circuit grinding with flash flotation, the interaction of flash flotation with grinding can be estimated. The models can be used to predict the effect of various changes to the operating conditions on circuit performance as well as the expected grinding performance in the absence of flash flotation. This enables the effect of flash flotation and any possible benefits to be evaluated.The model was developed from unit models of the ball milling, hydrocyclone classification and flash flotation processes. An empirical model was used for the flash cell, and generic models were fitted to the ball mill and hydrocyclone based on the matrix model and the Plitt model respectively. The data required for the development of the models was obtained from plant surveys of the Kanowna Belle gold mine and laboratory batch grinding and flotation tests.The model accurately represents the plant grinding and flash flotation circuit while operating under normal conditions. Simulation of the circuit using the model enabled the effect of variations to flash cell operating conditions on the flash concentrate, recirculating load and cyclone overflow to be determined.     

选矿过程矿浆液位的模糊控制算法研究

针对选矿过程分级环节泵池中的矿浆液位,设计了模糊智能控制器。利用模糊控制算法,通过变频调速技术,实现对泵池内矿浆液位的控制,来解决矿浆液位剧烈变化引起泵的吞吐量变化,以致水力旋流器工作分级效果降低等问题。仿真结果表明,系统的稳态误差小于0.17%,提高了水力旋流器的分级能力。     

多宝山铜矿二段磨矿分级系统对比研究

黑龙江多宝山铜矿石为典型的低品位硫化铜矿石,原矿Cu品位为0.41%,目的矿物与脉石矿物嵌布粒度细,精矿指标受磨矿作业效率的影响较大。多宝山铜矿选厂的二期工程分为两个系列,现有选矿工艺流程为闭路磨矿分级作业,能基本满足生产要求,但存在水力旋流器循环负荷过大、立磨机过磨现象严重的问题。对现有磨矿分级工艺进行优化研究,改为半开路磨矿作业后,现存生产问题得到有效改善,磨矿产品铜品位提高到了20.05%,回收率提高到了90.18%,同时能有效降低生产能耗。     

Analysis and validation of a run-of-mine ore grinding mill circuit model for process control

A simple and novel non-linear model of a run-of-mine ore grinding mill circuit, developed for process control and estimation purposes, is validated. The model makes use of the minimum number of states and parameters necessary to produce responses that are qualitatively accurate. It consists of separate feeder, mill, sump and hydrocyclone modules that can be connected to model different circuit configurations. The model uses five states: rocks, solids, fines, water and steel balls. Rocks are defined as too large to be discharged from the mill, whereas solids, defined as particles small enough to leave the mill, consist of out-of-specification coarse ore and in-specification fine ore fractions. The model incorporates a unique prediction of the rheology of the slurry within the mill. A new hydrocyclone model is also presented.The model parameters are fitted to an existing plant’s sampling campaign data and a step-wise procedure is given to fit the model to steady-state data. Simulation test results of the model are compared to sampling campaign data of the same plant at different steady-state conditions. The model shows promise in estimating important process variables such as mill power and product particle size and is deemed suitable for process control studies.     

磨矿预先筛分工艺的工业实践

新疆某铜矿根据原矿含泥多的性质增设磨矿预先筛分,为综合评价其在生产中的使用效果,考察了原矿、筛上产品、筛下产品、球磨排矿、旋流器沉砂和溢流的粒度组成情况,并通过增设前后技术经济指标对比,证实了预先筛分对提高磨机利用系数、降低能耗、提高产能起到明显促进作用,此项工艺的成功应用,对含泥多、粒度细的矿山企业起到良好的示范效果。     

Integrated simulation of grinding and flotation application to a lead-silver ore

The paper outlines a procedure to simulate a grinding -flotation plant. Population balance models are used to describe the grinding, classification and -flotation processes. In the grinding and classification models particles are characterized by their size, while in the flotation models particles are characterized by their size and mineral composition. The link between the grinding and flotation circuits is made by an empirical model that generates the mineral-size particle population from the size distribution of the grinding circuit product. The simulator is calibrated using plant data collected from the Peñoles-Fresnillo PbAg concentrator in Mexico.     

旋流器用于氧压酸浸闪锌矿磨矿前预先分级的试验研究

某冶炼厂使用立式砂磨机对二段浸出给矿进行开路磨矿, 但由于磨矿浓度低, 矿浆通过磨机时间短, 导致磨矿粒度偏粗, 影响浸出率。针对这一问题, 提出了使用分级旋流器预先分级的技术方案, 分级后的高浓度旋流器底流进入砂磨机磨矿。试验结果表明, 通过调节旋流器的结构与操作参数, 既可以获得用于浸出的粒度合格的溢流, 又可获得浓度大于50%的适合砂磨机磨矿的底流。旋流器预先分级能减轻磨机的负荷, 提高磨矿浓度, 有利于磨矿效率的提高和浸出率的改善。     

基于POS-BP的磨矿过程磨机负荷智能分析方法研究

主要针对有色金属行业选矿厂的磨矿过程半自磨机、球磨机等磨矿设备的负荷进行分析,利用OPC技术,通过计算机实现对磨矿过程的实时工艺数据的采集、处理、分析存储,利用POS-BP算法构建磨机功率软测量模型,从而实现对磨机功率的在线预测分析,之后结合案例分析技术,实现对磨机负荷的智能在线分析,能够有效地减少磨机涨肚次数,提高磨机处理量以及磨矿粒度合格率,降低衬板和钢球损耗,并且预测值可以为磨矿过程的优化控制、专家控制等先进控制提供有效的参数依据,从多方面提高磨矿过程乃至整个选矿过程的运行效率,从根本上提高矿山企业经济效益。     

Recovery vs. mass pull: The link to air recovery

In recent years, developments in control strategy for banks of flotation cells have included process control based on mass pull. Mass pull, or the flowrate of solids reporting to the concentrate, is affected by changes in froth structure and stability which are in turn affected by changes in operating parameters such as air flowrate and froth depth.Air recovery, or the fraction of air entering a cell that overflows the lip as unburst bubbles, is a robust, non-intrusive measure of froth stability that passes through a peak as cell air rate is increased. Furthermore, it has been shown that when operating a cell at the air rate that yields the ‘Peak Air Recovery’ (PAR), an improvement in flotation performance, particularly mineral recovery, can be obtained.In this paper, results from industrial experiments are reported that compare the effect of air rate on air recovery and flotation performance, and specifically the effect on mass pull and mineral recovery. The results show that an increase in mass pull does not necessarily yield an increased mineral recovery in all cases, since it is dependent on whether the air rate must be increased or decreased to obtain the ‘Peak Air Recovery’. This work shows the potential gain to be made from control using air recovery measurements and operating at PAR conditions.     

江西某钼矿选矿试验研究

分析了江西某钼矿的有用矿物组成及粒度特征,通过试验确定了该矿物浮选分离的合适磨矿细度、粗浮选合适的捕收剂煤油和起泡剂松醇油的用量、1次精选的抑制剂Na2S的用量、1次扫选捕收剂煤油和起泡剂松醇油的用量,并对探索试验确定的1粗1扫6精闭路流程进行了试验,获得了钼品位45.23%,回收率85.14%的钼精矿。     

和睦山选厂分级磨矿联合作业新工艺的研究与应用

针对和睦山选矿磨矿系统现有生产工艺,高压辊磨机开路超细碎物料粒级20-0mm,因其粒级范围较宽且矿石物料潮湿直接进入磨机,加之矿物特性大量脉石的混入、部分矿物过磨等问题,存在磨机处理能力和处理效率不理想等问题。通过试验研究,成功将重磁拉选矿机（ZCLA）应用于磨矿给矿的强弱磁性矿物的回收,同时配套自主设计的绞笼式脱水分级筛设备,探索研究了选矿分级磨矿联合作业新工艺,形成粗粒分选分级磨矿组合,实现提前选别、提前分级,减少磨矿负荷达到降低磨矿成本,最终提前抛尾产率大于17%,磨矿系统处理能力提高20%,为铁矿山宽粒级湿式预选与磨矿工艺开拓新的技术模式,经济效益显著,具有良好的推广应用前景。     

低灰浮选尾煤的磨矿脱泥浮选工艺试验研究

针对河北唐山地区煤炭黏土含量大、多高灰细泥、浮选效率低的问题,采用磨矿、小锥角水力旋流器脱泥、分步释放浮选等试验方法进行了浮选工艺试验研究。结果表明：采用150 mm与75 mm旋流器串联脱泥工艺,底流和溢流灰分差值为13.05%,说明旋流器串联脱泥工艺起到了较好的效果,能分离部分高灰细粒级煤泥,对底流进行分步释放浮选试验研究,在保证精煤质量前提下,精煤产率也相应得到提高,说明采用小锥角水力旋流器对原煤泥进行浮选前脱泥,能够有效降低高灰细粒级对浮选的影响,提高精煤的浮选效率;浮选尾煤灰分仍然较低,为38.27%,对低灰尾煤进行磨矿-脱泥-浮选试验,精煤产率为35.47%,综合精煤产率（占全级）相比较原煤泥直接浮选提高率达54.20%。     

碎磨过程控制技术在某多金属矿选矿厂的应用

自动控制系统在选矿生产中发挥了越来越重要的作用,针对某多金属选矿厂碎磨过程中的普遍问题,详细介绍了破碎过程控制策略和磨矿过程控制策略。碎磨过程控制技术在该选矿厂应用后,取得了良好的应用效果,不仅实现了提高碎磨生产能力、稳定生产指标的目标,同时也达到了节能降耗、减员增效、降低劳动强度的目的。     

铁多金属选矿厂智能控制系统设计与应用

数字化选矿控制系统在保障工艺流程、设备稳定运转的同时,重在提高生产系统的抗干扰能力及自适应能力。通过对生产数据长期不断的挖掘分析,实现生产过程操作方式的迭代优化。本文主要是对某铁多金属选矿厂的碎磨及浮选过程进行智能控制系统设计及实施。通过磨矿智能控制系统向基础自动化的单元给矿、补水、调频回路下达优化控制指令,平稳生产流程,提高了溢流产品质量;浮选智能控制过程通过粒度在线分析与智能充气控制系统,提升作业流程稳定性,实现流程产率优化,稳定了精矿品位。     

冀南邯-邢地区中小规模铁选厂选矿技术特征

冀南邯-邢地区中小规模铁选厂破碎阶段多采用两段破碎工艺,破碎设备主要为颚式破碎机。最终破碎产品粒度较大,最大粒度不小于50mm。破碎阶段普遍配置磁滑轮干式预选。采用开路磨矿或闭路磨矿,磨矿段数为一段或两段,磨矿设备多采用中小规格湿式球磨机。广泛采用高频细筛进行分级,部分选厂采用螺旋分级机。采用两段或三段磁选,磁选设备为永磁筒式磁选机,型号多样。选别流程有直接磁选和阶段磨矿阶段磁选等方式。精矿脱水采用真空过滤机或沉降池,尾矿处理采用直接排放、水力旋流器浓缩排放或浓缩过筛后固态堆存。该地区铁选厂选矿技术还有有很大的发展空间。     

一段磨矿分级应用水力旋流器的研究与实践

通过在2座大型选矿厂一段磨矿作业用水力旋流器取代螺旋分级机的研究与实践表明，球磨机排矿在给入水力旋流器之前不增设除渣系统仍可以保证水力旋流器的稳定运转。水力旋流器的分级效果与矿石的可磨性质有重要关系，对于易磨物料，其分级效果明显优于螺旋分级机；而对于硬度高、难磨物料，其溢流细度的稳定性略低于螺旋分级机。在一段磨矿产品即为最终磨矿产品的情况下，须设置简易的控制分级以筛除混入水力旋流器溢流中的少量粗大颗粒，确保稳定合格精矿产品的产出。     

某铅锌矿磨矿分级循环系统降比提效试验研究

针对国内某铅锌选矿厂磨矿分级循环系统的循环负荷高、水力旋流器分级效率和球磨机磨矿效率低等问题,对现场磨矿分级系统进行流程考察和问题诊断,对试验样进行了岩矿性质测定和工艺矿物学研究,基于矿石碎磨特性开展了球磨机磨矿介质尺寸和级配的理论计算、实验室磨矿对比试验、工业应用试验。球磨机介质级配优化后,磨矿分级系统中-0.074mm粒级的返砂比由试验前的467.19%降至224.66%,分级量效率由试验前的52.26%提高至68.34%,分级质效率由试验前的46.72%提高至57.21%,磨机-200目利用系数由0.24t/(m3·h)提高至0.40t/(m3·h),磨机磨碎+0.15mm粗粒级效率由21.95%提高至38.09%,实现了磨矿分级系统中球磨机和分级机效率双提升。