高压辊磨机粉碎工艺国外应用进展与发展趋势

基于层压粉碎原理,高压辊磨机具有处理量大、能量利用率高、粉碎产品粒度细等特性,已经广泛应用 于冶金矿山领域,且节能降耗效果显著。 文章总结了开路粉碎、边料返回半闭路粉碎和筛分(包括干法筛分和湿法筛 分)全闭路粉碎三种粉碎工艺的选择依据。 结合高压辊磨机在金刚石解离、铁矿球团原料预处理、(半)自磨顽石破碎 和金属矿磨前粉碎领域的典型应用案例,重点阐述了高压辊磨机的粉碎工艺流程、设备型号、操作参数及应用效果。 不断提高粉碎效率、降低粉碎成本仍是高压辊磨机粉碎工艺的发展方向。 虽然多台高压辊磨机串联配置、高压辊磨 机与风力分级设备配置、高压辊磨机与搅拌磨机直接配置等新工艺发展不够成熟,但节能降耗优势明显,有望为冶金 矿山物料高效粉碎提供新的解决方案。     

Flowsheet considerations for optimal use of high pressure grinding rolls

High pressure grinding roll (“HPGR”) technology is very rapidly gaining a wide acceptance within the mineral processing industry. Benefits, including a superior energy efficiency and a lower overall operating cost of an HPGR based circuit compared to alternative technologies have been demonstrated at a number of operations throughout the world. Increasing numbers of units are presently being installed in the minerals industry world-wide. This trend is an excellent reflection of the confidence now placed in the technology by new and existing users.This paper summarizes basic principles of the equipment and of various options how to include an HPRG in the grinding circuit for most efficient use. Case studies demonstrate the application of HPGR’s in different grinding circuit set-ups and for the comminution of different ore types. Benefits of the options of open circuit grinding, closed circuit grinding incorporating wet and dry screening as well as the option of achieving a finer grind by recirculating part of the HPGR product using a mechanical splitter are discussed.From a processing point of view the effects of partial product recycle are detailed and some guidance for selection of cut size between HPGR and ball mill is provided.     

罗河铁矿复合铁矿石高压辊磨工艺应用研究

为了解高压辊磨破碎对罗河铁矿选矿厂细碎产品可磨性的影响,对现场细碎产品进行了开路辊压破碎、边料返回闭路辊压破碎试验,边料返回闭路辊压破碎产品与现场细碎产品相对可磨度测定试验,样品和高压辊磨机边料返回闭路破碎产品球磨功指数测定试验,以及增设高压辊磨工艺后一段球磨扩能效果分析。结果表明：①高压辊磨作业可大幅度提高产品中细粒级含量,边料返回闭路破碎试验产品-3 mm粒级含量由辊磨前的56.73%提高至85.30%,提高28.57个百分点;-5 mm粒级含量由辊磨前的67.79%提高至92.65%,提高24.86个百分点;单位处理量为252 ts/（hm3）。②高压辊磨作业可显著改善入磨矿石的磨矿性能,当磨矿细度为-0.075 mm占60%时,与样品相比,高压辊磨机边料返回闭路破碎产品的相对可磨度为1.294;样品经高压辊磨破碎后,其球磨邦德功指数由16.15 kWh/t降至13.75 kWh/t,降幅为14.86%。③选矿厂增设高压辊磨边料返回超细碎作业后,由于入磨矿石可磨性的改善,一段球磨的产能可提高35.41%。     

Comparison of open and closed circuit HPGR application on dry grinding circuit performance

A conventional cement grinding circuit is composed of a two compartment tube mill, a mill filter which collects the fine material inside the mill and a dynamic air separator where final product with required fineness is collected. In general the material fed to the circuit has a top size of 50 mm which is very coarse for the ball mill. For this purpose, later in 1980s, high pressure grinding rolls (HPGR) has found applications as a pregrinder which increased throughput of the grinding circuit at the same fineness.In early applications, HPGR was operated in open circuit. But later as the operating principle of the equipment based on the compression, some portion of the HPGR discharge recycled back to improve efficiency of the mill or operated closed circuit with classifiers. Within this study effect of open and closed circuit HPGR applications on dry grinding circuit performance was examined. For this purpose sampling studies around three different cement grinding circuit were completed. In the first study, a circuit including open circuit HPGR, ball mill and air separator was sampled and chosen as the basic condition. As the final product size distribution is important for grinding circuit, model structure of each equipment was developed. The second and third surveys were carried out around closed circuit HPGR operation with V and VSK separator to develop models for the separators. Finally the separator models were used in basic condition to simulate closed circuit HPGR application.It was understood from the studies that closed circuit HPGR operation improved the overall circuit efficiency at the same final product fineness by reducing the specific energy consumption.     

The effect of using different comminution procedures on the flotation of Platinum-Group Minerals

The use of High Pressure Grinding Rollers (HPGR) has been widely reported to have major benefits in the treatment of minerals such as iron ore and diamonds. To date there have been few investigations into its use in the treatment of ores containing Platinum-Group Minerals (PGMs). HPGRs are known to reduce energy consumption and wear costs and improve the throughput in the circuit. In the present investigation the effect of the comparative use of HPGR and conventional crushing in combination with either dry or wet rod milling on the flotation of PGMs was studied using batch flotation. Previous studies of a base metal sulphide had shown that either HPGR or conventional crushing followed by dry milling produced the highest grades and recoveries (Palm et al., 2010). However in the present study it was observed that a similar treatment of Platinum-Group Minerals produced the poorest results and the highest grades and recoveries were obtained for the case of conventional crushing in combination with wet milling. The HPGR showed no advantages in terms of flotation performance and dry milling produced particularly poor flotation results.The results were investigated further using various surface characterization techniques in order to determine the reason for the decrease in grades and recoveries of platinum when using dry milling and HPGR as opposed to the case for base metal sulphides. The feed and product samples were analysed using ToF-SIMS, XPS and MLA. The paper will propose reasons to explain the different flotation behaviour of the two ore types following the various comminution processes focusing on the surface characteristics of the ores, the particle size distribution and the pulp chemistry.     

The effect of using different comminution procedures on the flotation of sphalerite

High Pressure Grinding Rollers (HPGR) are known to reduce energy consumption and wear costs and improve the throughput in the circuit. It has been suggested that they can also modify the liberation characteristics of the ore. In the present study the effect of using conventional crushing as opposed to HPGR in combination with either dry or wet milling was investigated using a base metal sulphide, viz. sphalerite, in order to determine whether there may be an improvement in flotation performance following the use of different comminution procedures. It was found that, irrespective of the crushing procedure (HPGR or conventional), dry milling resulted in the highest grades and recoveries of zinc. These were typically 94% recovery at 40% grade. In order to gain an insight into the effect which these comminution procedures had on the ore, samples of feed and product were investigated using surface analytical techniques. Mineralogical analyses showed no differences in the liberation characteristics of sphalerite irrespective of the comminution procedures used. However, dry milling produced a lower d50. The paper proposes possible reasons to explain these observations.     

高压辊磨机粉碎行为研究进展

高压辊磨机粉碎原理为层压粉碎，具有处理量大、节能高效等特点。与传统破碎方式相比，高压辊磨机粉碎产品细粒级含量高、微裂纹发育、矿物解离度高、邦德球磨功指数低，还有助于下游选别或浸出作业。随着辊面抗压强度和抗磨蚀性能不断增强，高压辊磨机已经广泛应用于冶金矿山领域，如金刚石与围岩解离、球团原料铁精矿预处理、金属矿磨前（超）细碎，（半）自磨工艺顽石破碎等。高压辊磨机的成功应用与其粉碎行为密切相关。文章依次从高压辊磨机的研发背景、工作原理、辊面压力分布、宏观粉碎过程、料床应力响应、粉碎产品特性等方面系统评述了高压辊磨机的粉碎行为，并分析了边缘效应和辊面磨损的产生机理、负面影响及其应对措施，旨在全面地阐述高压辊磨机粉碎行为。     

The effect of feed moisture on the comminution efficiency of HPGR circuits

The comminution efficiency of high-pressure-grinding-rolls (HPGRs) is a well described function of a number of feed parameters including grindability, abrasion index, granulometric composition, top size and particle size distribution. Far less studied is the effect of feed moisture. This paper investigates both the overall and the specific comminution efficiency of a circuit consisting of a pilot HPGR unit followed by a batch ball mill as a function of the moisture level in the HPGR feed. Forsterite olivine sand (−7 mm) supplied by Sibelco Nordic was used as feed material. The results showed that the relationship between moisture and crushing efficiency for both the HPGR and the circuit can be described successfully by means of a parabolic function. Dry material, as well as that with the highest moisture content, showed the lowest particle size reduction ratios irrespective of the specific grinding force level. The paper also analyses the phenomenon of flake generation and shows that the feed moisture influences the flake content in the coarser size fractions of the HPGR product.     

齐大山铁矿石高压辊磨产品磨矿及解离特性研究

以齐大山铁矿细碎矿石为对象,考察其高压辊磨机粉碎产品的磨矿特性和单体解离特性,并与实验室颚式破碎机粉碎产品进行比较,结果表明：当目标粒度分别为0.074和0.280 mm时,辊压产品的邦德球磨功指数分别比颚破产品的降低13.96%和28.23%;在-0.074 mm占80%磨矿细度下,-3.2和3.2~0.074 mm辊压产品与对应颚破产品的相对可磨度分别为0.83和0.86;辊压产品与颚破产品相比,-0.5 mm粒级中铁矿物的单体解离度高15.16个百分点,不同磨矿细度下的磨矿产物中铁矿物的单体解离度高5.55~0.98个百分点;辊压产品磨矿产物中的连生体属于二次磨矿时易于解离的连生体,而颚破产品磨矿产物中的连生体属于二次磨矿时难以完全解离的连生体。     

马坑磁铁矿石高压辊磨—湿式中磁预选—阶段磨选工艺试验

为探索采用高效碎磨工艺处理福建马坑铁矿石的可行性,进行了高压辊磨—湿式中磁预选—阶段磨选工艺流程试验。结果表明:较常规碎矿工艺,高压辊磨破碎获得的产品细粒级含量显著提高,能够满足湿式中磁预选的粒度要求;磨矿条件相同时,高压辊磨产品相对传统颚式破碎产品新生成-0.074 mm粒级含量高,相对可磨度高;高压辊磨产品(-5 mm)经湿式中磁预选—两阶段磨矿弱磁选,可在磨前抛出38.88%的合格尾矿,并可获得铁品位为66.75%、磁性铁品位为65.95%、铁回收率为80.21%、磁性铁回收率为96.25%的铁精矿,精矿铁品位较现场提高了2.66个百分点、铁回收率提高了0.30个百分点,可作为马坑铁矿节能降耗、提质增效改造设计的依据。     

高压辊磨机挤满给料控制系统开发与应用

为了提高高压辊磨机的设备利用效率,减少空转率,本文提出了一套完整的高压辊磨机给矿控制策略。该控制策略以挤满给料专家控制算法为核心,加之对整个高压辊磨机作业回路进行故障监测与诊断,保证了高压辊磨机给料的持续和稳定性,提高了作业回路的生产效率和安全性。     

破碎方式对贫磁铁矿预选效率和磨矿特性的影响

对贫磁铁矿进行高压辊磨破碎和传统颚式破碎, 对比研究了不同破碎工艺对破碎产物预选分离指标和磨矿特性的影响。结果表明, 与传统颚式破碎相比, 高压辊磨的破碎比(F₈₀/P₈₀)高31.52%, 产物中-0.074 mm粒级含量高8.46个百分点;干式抛尾精矿全铁品位高2.66个百分点, 全铁回收率和磁性铁回收率分别高4.54和4.47个百分点。在-0.074 mm粒级占85%的磨矿细度下, 高压辊磨产物与传统破碎产物的相对可磨度为1.24, 高压辊磨产物在磨矿过程中细粒级的生成速率比传统破碎快;高压辊磨破碎产物表面产生的微裂纹比传统破碎多, 这是高压辊磨能提高破碎产物预选分离指标和可磨性的主要因素。     

高压辊磨超细碎在贫磁铁矿石预选中的应用

从高压辊磨机的工作原理及粉碎产品特性出发,分析了高压辊磨超细碎在贫磁铁矿石预选工艺中的作用。高压辊磨机特有的层压粉碎方式使其粉碎产品具有细粒级含量高、微裂纹发育充分、解离特性好等特点。高压辊磨超细碎—预选工艺能够在贫磁铁矿石入磨前抛除大量合格尾矿,减少入磨量,提高入磨品位,降低矿石的Bond球磨功指数,提高选别效率,有利于实现节能降耗。指出今后应加强高压辊磨设备与矿石性质及生产工艺的适应性研究,发展高效、低耗的新型辊磨设备,高压辊磨机与先进的预选设备配合使用时效果更好,因此针对高压辊磨产品的特性,研发配套的先进预选设备,对提高高压辊磨超细碎—预选指标具有重要意义。     

高压辊磨机在矿物加工领域的应用

结合国内外一些典型的工业实例,从金刚石矿粉碎、铁矿石加工、有色和贵金属矿石粉碎3方面综述了高压辊磨机在矿物加工领域的应用进展和现状,并分析了高压辊磨机在矿物加工领域的发展趋势。     

基于矿物基因的某鞍山式磁铁矿高压辊磨- 干式预选新工艺系统研究

研究了沉积变质岩型磁铁矿的主要地质背景和矿物基因的关系，认为矿石的矿物组分、结构构造、嵌布特性、矿物共生关系等信息是矿物基因的内在表达；矿石力学特性、解离特性和分选特性是矿物基因的外在表达；而各种地质作用的交互式影响，是造成不同类型矿石甚至同类型矿石分选差异大的主要原因。利用 MLA 对本溪某超贫超细磁铁矿进行了矿物基因学研究，初步解释了该鞍山式沉积变质岩型磁铁矿形成过程中前期的各沉积作用及后期的各变质作用与该矿石的矿物基因表达之间的关系。针对该矿石的矿物基因特性，创新性地设计出高压辊解离调控碎磨-精准分选的新工艺和新装备，分选指标比传统高压辊湿筛湿选具有明显的优势。新系统装备在 1 000 万 t/a 的新建项目应后，顺利达产达标，取得了可观的经济效益。基于矿物基因特性的高压辊磨解离调控分选系统解决方案对其它鞍山式沉积变质岩型磁铁矿的大规模低成本开发利用具有重要推广价值，为中国钢铁行业合理开发和利用低品位难选铁矿资源、保障铁矿石国内供给提供了有力的技术支撑。     

某赤铁矿浮选工艺流程试验研究

简要介绍了某赤铁矿的矿石性质,从磨矿细度、药剂种类和用量等方面系统地研究了该矿物的浮选工艺技术条件,并参考条件试验结论完成了一粗三精两扫、中矿顺序返回的闭路流程试验,获得了铁品位62.55%、铁回收率71.57%的铁精矿。     

Investigation of particles with high crack density produced by HPGR and its effect on the redistribution of the particle size fraction in heaps

The application of comminution technology such as the high-pressure grinding rolls (HPGRs), which is able to generate a high density of cracks in the ore particles, is favourable for leaching processes. Extraction of metallic values by the heap leach process, can take place on the particles with partial exposure of mineral grains, if it can provide sufficient surface front for chemical attack by leaching solution. The aim of this study was to assess the benefits of high crack density in the ore particles produced using the HPGR and how it could diminish due to inadequate percolation of the leaching agent.A zinc ore was comminuted using HPGR at three different pressure settings and with a cone crusher for the control experiment. Subsamples from the (+23/−25, +14/−16, +5.25/−6.75 mm) size fractions were characterized and packed into leach reactors. The reactors were stopped from time to time to investigate the progress of crack and micro-crack growth and its effect on metal extraction using the X-ray computed tomography (CT). The results are validated with those obtained using traditional techniques such as SEM and QEMSCAN. Investigation of the leach reactors residue indicated significant changes in the particle size distribution (PSD) of initial feed toward the fine size fraction. The residues from the reactors leaching the material prepared using the HPGR product contained more fine particles than the reactors, which were fed by cone crusher product. These differences were up to 10.3%.     

Effect of High Pressure Grinding Rolls (HPGR) pre-grinding and ball mill intermediate diaphragm grate design on grinding capacity of an industrial scale two-compartment cement ball mill classification circuit

Effect of High Pressure Grinding Rolls (HPGR) pre-grinding and two-compartment ball mill intermediate diaphragm grate design on grinding capacity of an industrial scale conventional two-compartment ball mill cement grinding and classification circuit was investigated. For this purpose, cement clinker was crushed in an industrial scale HPGR in open circuit and fed to a Polysius® two-compartment ball mill and air classifier closed circuit. Two-compartment ball mill intermediate diaphragm middle grate design was changed when HPGR crushed clinker was fed to the circuit to obtain optimum flow of material from the first compartment into the second compartment. Modifications on the diaphragm design were required due to the increased throughput when processing HPGR product. Two sampling campaigns were performed at the steady state conditions of the circuit. Raw clinker (uncrushed clinker) was fed to the conventional two-compartment ball mill air classifier circuit in sampling campaign-1 whereas HPGR crushed clinker was fed to the same circuit with modifications on the intermediate diaphragm middle grate design in sampling campaign-2. Mass balanced tonnage and particle size distributions were estimated by using JKSimMet Steady State Mineral Processing Simulator in both sampling campaigns. Polysius® two-compartment ball mill was modeled by using perfect mixing modeling approach (Whiten, 1974). Specific discharge and breakage rates in the grinding compartments were estimated by using the two-compartment ball mill model structure proposed by Genç and Benzer (2015). Specific discharge rates were found to increase at coarse size ranges when raw clinker was fed to the circuit in compartment-1. However, specific discharge rates of particles were increased slightly at coarse size ranges in the second compartment at higher mill capacity condition. Specific breakage rates were increased when the circuit was fed with HPGR crushed clinker. Modifications in the circuit and the ball mill intermediate diaphragm grate design enabled the optimization of the grinding capacity of the conventional two-compartment ball mill cement grinding and classification circuit. Ball mill grinding and classification circuit capacity was increased by 10% and specific energy consumption of the ball mill was decreased by 9.1%.     

Modeling the contribution of specific grinding pressure for the calculation of HPGR product size distribution

Vale, one of the largest mining companies in the world, has prioritized the development of HPGR technology for practical application in its current projects. An existing model for the HPGR, capable of predicting product size distributions, has been evaluated under distinct grinding conditions for one feed material. The effect of grinding pressure and feed size distribution were investigated. The model response showed a clear dependency of product size distribution with specific grinding pressure. As a result, specific grinding pressure was incorporated into the model, allowing for predicting product size distribution at practical values of this important process parameter. Based on this result, a characterization procedure was envisaged so as to produce parameters for the model. The procedure does not require complex experimental procedures, and all of the testing can be carried out in an expedited form in an instrumented bench-scale HPGR, using small samples of about 10 kg. The only analyses required are size distributions. The model was implemented in the Modsim? plant-wide simulator, with facilities to predict product size distribution for any roll diameter, length and speed of an HPGR machine.     

华北某贫赤铁矿选矿试验研究

简要介绍了华北某贫赤褐铁矿的矿石性质,重点研究了磨矿产品细度和反浮选药剂用量对产品指标的影响。试验研究结果表明,采用2阶段磨矿,1次中磁1次强磁预先抛废,1粗1精3扫、中矿顺序返回闭路反浮选流程处理,可以获得铁品位为66.07%、铁回收率为80.53%的精矿。