铁矿石物料颗粒床压载粉碎试验研究*

利用活塞缸体压载装置,在压力试验机上对三种铁矿石物料分别进行了窄粒级和宽粒级给料的颗粒床粒间粉碎试验研究。试验用的5个窄粒级为2.5～3.2,1.6～2.0,0.8～1.0,0.4～0.5和0.2～0.25 mm,宽粒级为0～4.0 mm;压强变化范围为30～360 MPa。结果表明,颗粒床单位质量物料吸收的能量与压强有线性关系;压载产物细度随压强的增加而提高,但提高的幅度随着压强的增加而变小;不同粒度的窄粒级颗粒床的压载产物粒度分布曲线之间不存在自相似性。试验数据可用于建立关于这三种矿石物料的粒间粉碎数学模型。     

颗粒床压载粉碎对某硫化铜矿石矿物解离的影响

颗粒床压载粉碎是高压辊磨机粉碎矿石的主要作用机制。利用活塞-缸体压载装置进行了将高压辊磨机作为终磨设备对某硫化铜矿石的粉碎及铜矿物解离效果影响的模拟试验研究,包括窄粒级颗粒床压载粉碎试验和宽粒级颗粒床压载粉碎闭路试验,并将闭路试验结果与球磨磨矿闭路试验结果进行了比较。窄粒级试验给矿为2 360/3 350 mm粒级的物料,宽粒级试验给矿为0/3 350 mm粒级的物料。粉碎产物中铜矿物的解离分析采用BPMA型工艺矿物学参数自动分析仪完成。根据试验结果从产物粒度分布、铜金属的粒级分布、铜矿物粒度和颗粒含量分布、铜矿物粒级解离度及铜矿物整体解离度等方面讨论了压载强度及粉碎方法对铜矿物解离效果的影响。     

高压辊磨机选型试验的研究现状

结合高压辊磨机中物料粉碎机理,介绍了影响高压辊磨机粉碎效果的关键因素,评述了高压辊磨机设备选型试验的研究现状。高压辊磨机粉碎物料的效果主要受物料性质、辊压机工作参数及粉碎工艺等的影响。通过小型及半工业型高压辊磨机粉碎试验能够为高压辊磨机的设备选型和流程设计提供依据,但试验过程相对复杂。颗粒床活塞压载试验和数学建模尽管能够对矿石料层粉碎的工作压力、比能耗、产品粒度分布等进行有效预测,但和高压辊磨机设备选型的经验公式一样均需要对其适用性进行验证。指出高压辊磨机未来的研究方向为粉碎过程中能量传递模型、矿石碎磨特性及对分选工艺影响等的理论基础研究,以及高压辊磨机在选矿流程中的数值模拟研究。     

不同施载压力下物料颗粒床压载试验

高压辊磨机的粉碎产品具有微裂纹多、细粒级含量高和单位破碎能耗低等优点,但其应用选型需要耗费大量矿石原料,进行相应的半工业试验,时间长、成本高。针对该问题,利用活塞缸体压载模具,通过压力试验机分别对金矿石、磁铁矿石及钒钛磁铁3种矿石进行颗粒床层间粉碎压载试验,初步模拟矿石的料层粉碎过程。结果表明:①同一矿物产品的负累计产率变化幅度与给料的粒级有关,给料粒级越小,产物负累计产率变化幅度越小;产品负累计曲线的变化趋势与矿石种类及加载压力有关,施载压力对金矿产品负累计产率的影响明显;当试验矿样为磁铁矿、钒钛磁铁矿时,随施载压力的增加,产品负累计产率逐渐增加,施载压力越大,负累计曲线斜率变化越明显;②随着加载压力的增加,比能耗增加;随着加载压力的增加,破碎比增加,在压力增加到一定程度后,破碎比增加速度降低或趋于平稳,变化趋势主要受矿石粒级和类型影响。③给料粒级较窄时,R_(50)的数值变化较小,当给料粒级较宽时,R_(50)数值变化较大;给料粒级对R_(80)的影响相对较小,在不同施载压力条件下的变化趋势较为稳定。该试验结果为高压辊磨机的工业参数选型提供了实验室研究基础,对高压辊磨机选型的进一步研究具有重要意义。     

粒度对方解石冲击粉碎影响研究

JK标准落重试验的样品粒度范围为-63.0+13.2mm。为了研究粒度尺寸对颗粒抗冲击粉碎能力的影响,以天然方解石为研究对象,将矿石粒度范围拓展到-13.2+4.75mm。通过JK落重试验方法分别测定-63.0+13.2mm和-13.2+4.75mm两个粒级范围内矿石抗冲击粉碎特性参数,以此来分析研究不同试验条件下颗粒抗冲击粉碎能力的变化。试验结果表明,方解石物料的冲击粉碎存在较明显的粒度效应,且随着粒度的减小,颗粒抵抗冲击粉碎的能力增大。这为运用JKSimMet软件中的变速率模型进行模拟时,粒度效应对模拟结果的影响提供了理论支持。     

粒度小于13.2 mm矿石颗粒的冲击粉碎试验研究

JK落重试验是测定矿石粉碎特性参数的一种方法。标准落重试验的试样粒度范围为-63.0+13.2 mm。在利用JKSim Met软件进行自磨/半自磨粉碎模拟时,由此试验获得的矿石特性参数被默认地运用于所有粒度颗粒的粉碎。以华东某金矿矿石为对象,进行了粒度小于13.2 mm矿石颗粒的冲击粉碎试验研究。结果表明,此矿石物料的粉碎存在粒度效应,随着粒度的减小,颗粒抵抗冲击粉碎的能力增大。另外还发现,试料制备时的破碎次数对颗粒的粉碎效果也有影响。     

对辊式破碎机岩石破碎特性研究

摘 要：针对岩石破碎过程的复杂性和传统BPM模型对其仿真的局限性的问题,提出一种通过EDEM-API二次开发所建立的改进的BPM模型（颗粒二次替换）,从而优化仿真效果的一种改进方法。将对辊破碎机模型分别导入Recurdyn与EDEM中,分别使用传统与改进的BPM模型对物料破碎过程进行仿真模拟。通过试验,分析在辊隙1mm、频率50HZ的条件下,入料粒度分别为8-10mm、10-12mm、12-14mm、14-16mm区间下各1kg矿石颗粒破碎后的粒级分布规律,利用MATLAB将仿真与试验所得碎后粒级进行统计。结果表明：辊缝和电机频率一定的条件下,不同粒度的物料破碎后粒级质量分布差异较小,优化后模型碎后质量分布仿真与实际结果误差度值E,相比优化前降低了3.391,辊子位移量分别为-0.08~0.06mm、-1.2~0.8mm之间,优化后模型仿真效果更好。     

铁矿石批量磨矿的模拟试验

天然磁铁矿石的批量磨矿试验是用总体平衡模型进行模拟的。研究了确定这种矿石的选择函数和碎裂函数的不同方法,矿石的7个单一粒级的磨矿试验是在一台半工业型球磨机中进行的。逆算得到的选择函数与选择函数S的试验测定值相比较。同样方法确定的碎裂函数用模拟结果检验。可以认为,如果一种物料的碎裂函数不能归一化,则必须进行大量单一粒级的磨矿试验,使得估算的选择函数和碎裂函数比较可靠。     

SCSE——表征矿石半自磨可磨度的新指标

JK落重试验及SMC试验作为测定矿石粉碎特性的试验方法在半自磨机选型和工艺条件优化中得到越来越多的应用。由JK落重试验或SMC试验获得的物料特性参数A和b是一种建立在特定粉碎数学模型基础之上的模型参数,这两个参数本身没有明确的物理意义,尽管其乘积A×b可作为衡量矿石抵抗冲击粉碎能力的一个指标,但A×b取值大小的工艺意义只有通过模型计算结果才能体现出来。为弥补这方面的不足,JKTech公司和SMCT公司新近联合推出了一种表征矿石半自磨可磨度的新指标——SCSE值。在综述JK落重试验、SMC试验以及利用JKSim Met软件进行半自磨磨矿流程模拟的方法和原理的基础上,介绍了这个新指标的定义、意义及局限性。     

一个用于闭路粉碎过程仿真计算的通用模型

由粉碎作业和分级作业构成闭路粉碎循环,是工业粉碎实践中常见的流程配置形式。本文从粉碎和分级的单元作业模型以及循环回路物料平衡原理出发,建立起一个描述闭路粉碎过程的通用模型。实际工业粉碎流程中最常见的两种闭路结构类型均可视为是这个通用回路的特殊形式。将本模型用于对粒间粉碎闭路循环的稳态仿真计算,得到的结果与实验室闭路粉碎试验结果拟合得很好。     

The effect of breakage mechanism on the mineral liberation properties of sulphide ores

The effect of particle-bed breakage mechanisms on the liberation properties of ores remains unclear. Surprisingly few studies have been published in this area and limitations in liberation measurement techniques previously used have prevented definitive conclusions from being reached regarding whether particle-bed breakage enhances the liberation properties of mineral ores relative to conventional grinding mechanisms. In this study, two sulphide ores of differing textures were comminuted to various size distributions using impact and particle-bed breakage mechanisms in a hammer mill and a piston–die compression unit respectively. The liberation properties of the various discharge samples were then characterised using a mineral liberation analyser – a mineralogical characterisation system based on automated scanning electron microscopy. It was found that the size-by-size liberation properties of both valuable and gangue mineral phases were independent of both the method used to comminute the samples, as well as the particle size distribution of the final products. These effects are discussed in terms of how they may be exploited in liberation modelling and characterising comminution circuit performance.     

Discrete element method simulation of bed comminution

This paper evaluates fragmentation behaviour, particle size distribution and liberation degree during bed comminution of particles. Three different cases of bed comminution are modelled through discrete element simulations. The role of stressing velocities on breakage, effects of crushing walls on fragmentation and influence of crushing gaps on liberation and particle size distribution are considered. The discrete element sample is modelled to represent the concrete specimens of B35 strength category.It has been observed that the particles around the stressing walls fail differently than the inner particles during bed comminution. The stressing velocity and the crushing walls have been found to affect the cracking mechanism of the particles. The liberation degree in bed comminution is less as compared to single particle crushing. The results presented in this paper can be used to model the liberation and recycling of valuable aggregates from cheaper matrixes.     

Modeling breakage of monodispersed particles in unconfined beds

Mathematical models of grinding mills and crushers are undergoing significant advances in recent years, demanding ever more detailed information characterizing ore response to the mechanical environment. In a mechanistic model of a comminution machine, the type of characterization data used should cover, as much as possible, the conditions found inside the size reduction machines. This applies to the particle size, the stressing energy and rates that particles are subject to, the breakage mechanism and the level of interaction of the particles during stressing, which all must be described appropriately. Whereas, a very large number of experimental techniques and published data exist that allows understanding and quantitatively describing the response of single particles to stressing, comparatively little information exists on the breakage of particles contained in beds. The present work investigates breakage of particle beds impacted by a falling steel ball in unconstrained conditions, such as those that are likely to be found in tumbling mills. The influences of particle size, impact energy, ball size and bed configuration are investigated for selected materials and a mathematical model is proposed that describes the influence of all these variables. The key element of this model is that it allows predicting breakage in monolayer unconfined particle beds with a combination of single-particle breakage data and functions that describe energy partition and volume of material captured in the bed. This model has been calibrated and validated using data from quartz, granulite, limestone and a copper ore, with good agreement.     

Überblick über Methoden der Mahlbarkeitsprüfung

The paper covers a selection of grindability tests described in literature for the characterization of the comminution behaviour of mineral matter down to a minimum particle size of the comminution product of approximately 0.02 mm. The test rigs, the test work, the characterization of the grindability and the correlation to the full scale apparatus are lined out. The test methods for impact, compressive and frictional stress with or without measurement of the energy input are commented and added by the methods developed at the Institute of Mineral Processing. Emphasis is laid on the method of the Optimized Comminution Sequence by means of which material parameters can be acquired rather independently from the influence of machinery. Three results from the extensive test-work with a comminution sequence covering a size range from 200 to 0.2 mm support Prof. H. J. Steiner’s concept of the Natural Breakage Characteristic and the limiting case of linear correlation between new created surface and energy input in the case of energy optimized comminution.     

云南某铜矿SABC碎磨流程能耗分布规律及能量基准评价研究

提高碎磨流程能量利用效率是降低碳排放的重要途径,而碎磨能耗分布规律研究与能量基准评价是提高能量利用效率的前提和基础。某大型铜矿SABC碎磨流程能耗分布规律研究结果表明,碎磨全流程比能耗为19.59kWh/t,半自磨机、球磨机、顽石破碎机的比能耗分别占全流程比能耗的36.76%、55.75%及0.83%;球磨机运行功率接近安装功率的93.40%,是限制碎磨系统产能进一步提升的瓶颈。以原矿代表性样品单颗粒冲击破碎试验为基础,建立了矿石粉碎模型,通过能量基准评价方法计算出SABC碎磨全流程理论最低粉碎能耗为8.96 kWh/t,分别对SABC碎磨全流程、半自磨+振动筛+顽石破碎作业、球磨与分级作业进行了能量基准评价,得出能量效率因子（BEF值）分别为2.19、1.71和2.60,进一步明确了提升球磨分级作业能量利用效率的必要性。能量基准评价研究为碎磨流程能量利用效率提供了统一、定量的评价指标,为碎磨全流程产能提升与节能降耗指明了优化方向。     

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。     

Energy efficient comminution under high velocity impact fragmentation

In mining operations, comminution processes are responsible for most of the energy used during mineral recovery. Low fragmentation efficiency of comminution in the range of 1-2% (Tromans, 2008) occurs due to the quasi-static nature of the process which is typically accompanied by low impact velocities. Accurate estimation of efficiency requires a measurement system to account for fractal parameters such as surface roughness and fracture surface area. Continuum breakage models of single particles fail to estimate the actual stress transformation that affects bulk material during comminution. In order to study comminution in a dynamic regime at higher strain rates than those of conventional equipment, a compressed-air apparatus designed to launch a projectile at velocities as high as 450 m s⁻¹ has been developed to measure the quantitative nature of high-speed impacts on aggregated rock samples. A method to calculate the energy efficiency is also presented. The results of experiments conducted on three materials suggest the energy efficiency of rock breakage can be improved by two or three times under high velocity impact for the same energy input level. The paper reports an empirical model of impact velocity and energy input and discusses the advantages and limitations of this model.