磨矿方式对菱镁矿可浮性的影响

立式辊磨机是一种集“碎、磨、烘干、分级”为一体的高效低碳型粉磨设备，具有结构简单、可靠性高、工艺流程短、占用空间小等优点。为了考察立式辊磨机磨矿对菱镁矿可浮性的影响，针对丹东宽甸某菱镁矿，分别采用立式辊磨机磨矿、球磨机干式磨矿以及球磨机湿式磨矿3种磨矿方式，研究对比了菱镁矿单矿物的可浮性。研究结果表明，立式辊磨机磨矿下，菱镁矿的回收率明显高于其他两种磨矿方式。通过比表面积分析、AFM检测以及药剂吸附试验可知，与球磨干式磨矿和球磨湿式磨矿相比，立式辊磨产品具有较高的表面粗糙度(2.76 nm)和较大的比表面积(0.259 4 m²/g)，这也导致了立式辊磨机磨矿产品对捕收剂的吸附量更大，从而更有利于菱镁矿在油酸钠体系下的浮选。     

立式辊磨机对方铅矿浮选行为的影响

针对方铅矿进行了立式辊磨机磨矿、球磨机干式磨矿和球磨机湿式磨矿3种磨矿试验，并考察了丁基黄药体系中，不同矿浆pH值、捕收剂和调整剂用量下，3种磨矿方式对方铅矿可浮性的影响。研究结果表明，立式辊磨机磨矿产品的回收率要明显大于球磨机干式磨矿和球磨机湿式磨矿，这主要是由于：立式辊磨产品的中间粒级含量为38.48%，比球磨湿式磨矿高9.05个百分点，比球磨干式磨矿高6.00个百分点；立式辊磨机磨矿产品的比表面积要高于其他2种磨矿方式；丁基黄药在立式辊磨磨矿产品的表面吸附量要明显大于其他2种磨矿方式。     

立式辊磨机对菱镁矿磨矿及浮选效果的影响

立式辊磨机是一种集中碎、粉磨、快速烘干、高效选粉等工序为一体的高效节能环保型设备,具有结构 简单紧凑、工作可靠、流程简单、占地面积小等诸多优点。 针对丹东宽甸某菱镁矿,分别进行立式辊磨机与球磨机磨 矿—浮选试验,通过对比磨矿能耗、磨耗、磨矿产品粒度特性、矿浆中 Fe3+浓度等数据,并比较了药剂制度对闭路试验 精矿指标的差异。 结果表明:立式辊磨机磨矿的能耗仅为球磨机磨矿能耗的 17%左右,立式辊磨机的磨耗约为球磨 机磨耗的 6%左右,同时立式辊磨机磨矿产品中有利于浮选的中间粒级(0. 105~ 0. 045 mm 粒级)含量要比球磨机磨矿 高 2. 39 个百分点、立式辊磨机磨矿矿浆中的 Fe³⁺浓度也仅为球磨机磨矿矿浆的 17. 86%;通过闭路试验精矿指标对比 表明,使用立式辊磨机磨矿,可有效降低油酸钠与六偏磷酸钠用量,并降低精矿中 CaO 品位,提升精矿质量。     

十二胺体系中不同磨矿方式对石英可浮性的影响

立式辊磨机是一种集中碎、粉磨、快速烘干、高效选粉等工序为一体的高效设备。本文研究了立式辊磨、干式球磨和湿式球磨三种磨矿方式下石英的表面特性,并考察了十二胺体系下,不同矿浆pH值、捕收剂和调整剂用量下,三种磨矿方式对石英可浮性的影响。结果表明,不同的浮选条件下,立式辊磨机石英样品的回收率基本都高于球磨干式磨矿和球磨湿式磨矿。较优的浮选工艺参数为矿浆pH值8.5,捕收剂十二胺用量为100mg/L,不添加六偏磷酸钠和水玻璃,金属阳离子CaCl2浓度100mg/L。立式辊磨机石英样品较高的表面粗糙度和比表面积提升了浮选过程中十二胺的吸附能力,从而提升石英的回收率。     

破碎方式对某磁铁矿石磨矿速度和Bond球磨功指数的影响

为验证破碎方式对磨矿速度和Bond球磨功指数的影响,使用某磁铁矿选矿厂的鄂式破碎产品、圆锥破碎产品和高压辊磨产品,分别进行磨矿动力学试验和Bond球磨功指数试验。结果表明：①高压辊磨产品的可磨性最好,圆锥破碎产品次之,鄂式破碎产品最差。同一破碎产品的磨矿速度随着磨矿时间的增加而降低。不同破碎产品,随着磨矿时间增加,颗粒性质逐步均匀并接近,磨矿速度逐步接近,破碎方式对磨矿速度的影响逐步降低。②Bond球磨功指数试验表明,在磨矿产品粒度大于0.10 mm时,破碎方式对磨矿的能耗影响显著,高压辊磨产品最节能;当磨矿产品粒度小于0.10 mm时,破碎方式对磨矿的能耗影响降低。破碎工艺中增加高压辊磨机,对于增大磨机处理量、降低磨矿能耗十分有益。     

基于MATLAB/Simulink的立磨机批次磨矿的建模与仿真研究

以总体平衡模型为基础, 使用动态系统模拟仿真软件MATLAB/Simulink对立磨机批次磨矿过程进行了建模与仿真。基于马钢集团东山选厂铁粗精矿实验室立磨机批次磨矿试验结果计算了碎裂分布函数b_ij和碎裂速率函数S_i。使用该模型对立磨机批次磨矿和连续磨矿分别进行了仿真运算, 两种情况的仿真结果与实测数据吻合良好, 为该模型应用到立磨机与旋流器组成的闭路磨矿分级系统的建模与仿真研究奠定了基础。     

紫金山铜矿微裂纹特性及其对磨矿动力学的影响

采用颚式破碎机、对辊破碎机和高压辊磨机对紫金山铜矿进行破碎,测定了1.7～3.35 mm粒级破碎产品的微裂纹、孔隙度特性,通过磨矿试验探究微裂纹特性对该粒级磨矿动力学行为的影响.研究结果表明,不同工作压力条件下的高压辊磨产品形成的微裂纹均比颚式破碎产品和对辊破碎产品多,矿石孔隙度更大;高压辊磨机工作压力为4 MPa的破...     

高压辊磨层压破碎对某铁矿石磨矿效果的影响

对某铁矿的传统破碎产品和高压辊磨层压破碎产品,分别进行了Bond球磨功指数试验、Levin试验和立式搅拌磨磨矿试验,探讨了高压辊磨层压破碎产品与传统破碎产品磨矿效果的差异。证明无论是在球磨还是在立式搅拌磨中,在一定的磨矿产品细度范围内,高压辊磨的层压粉碎作用可明显降低磨矿能耗,达到很好的节能效果。     

高压辊磨+搅拌磨在某复杂难选铁矿石选别工艺中的优越性研究

为了验证在某复杂难选铁矿石的选矿工艺中,应用高压辊磨机和立式搅拌磨的优越性,进行了一系列对比试验。结果表明,与颚式破碎机相比,高压辊磨机产品的粉矿率更高,产品的可磨性更好;与球磨机相比,立式搅拌磨机细磨效率更高、效果更好,相同磨矿细度下,立式搅拌磨机磨矿产品的解离度更高,磁选铁精矿品位也更高;高压辊磨+立式搅拌磨在处理复杂难选铁矿石方面具有显著的优势。     

不同破碎方式下产品磨矿特性的对比研究

对西藏墨竹工卡邦铺钼铜矿进行了高压辊磨和传统破碎,然后对两种产品进行了分批磨矿试验,应用磨矿动力学原理,并借助MATLAB 7.1软件分析了高压辊磨产品和传统破碎产品磨矿过程中各个粒级的磨矿速度。结果表明:在磨矿初期,高压辊磨产品的磨矿速度大于传统破碎产品的磨矿速度;在粗级别(-3.2+0.105 mm)中,高压辊磨产品磨矿速度的最大值高于传统破碎产品,而且粒度越粗,磨矿速度的最大值相差越大;随着磨矿时间的继续增加,磨机中粗粒级的含量越来越少,磨矿概率迅速降低,从而导致高压辊磨产品的磨矿速度小于传统破碎产品的磨矿速度,对于粗粒级(-3.2+0.105 mm)这种现象尤为明显;针对上述现象提出"高压辊磨—粗粒选择性快速磨矿"这一概念。     

辊压机挤压粉碎模型的研究

为了提高对辊压产品粒度预测的准确性,基于M.Torres提出的由于物料对辊面挤压力不均而进行分割的思想,对辊压机的挤压粉碎模型进行深入研究。利用滦县粉碎厂试验设备进行现场试验,对试验数据进行分析,用MATLAB软件对选择函数和破碎函数模型进行拟合,确定影响辊压机出料粒度的各个参数,得出相应的选择函数和破碎函数模型。对辊压机辊子进行轴向分割后,根据试验数据求出相应的模型参数。     

反击式破碎机破碎过程建模与仿真分析

为预测破碎产品粒度,有效控制破碎产品质量,基于总体平衡模型,建立了反击式破碎机的破碎过程模型,其中包括分级函数和破碎函数。确立了破碎产品粒度与破碎机转子半径、转子转速、给料粒度分布和给料速率的函数关系。为了解决给料粒度分布不均匀时,分析结果偏差较大的问题,提出采用粒度分布系数来描述给料粒度分布不均匀程度对分级函数的影响。利用CF250反击式破碎机进行破碎试验,对试验数据进行统计回归分析,建立破碎过程模型。以CF400反击式破碎机为算例,对不同转子转速和给料速率下的破碎产品粒度进行了仿真和试验分析,通过仿真分析结果与CF400反击式破碎机破碎花岗岩的试验数据相对比,验证了模型的可行性和可靠性。     

A new method for determination of fine particle breakage

Material characterization plays a crucial role by means of equipments efficiency and overall circuit performance. Material properties such as grindability, breakage, crushability, mineralogy can easily be determined by laboratory studies. These parameters are required for modeling and simulation works.Breakage behaviour of material is important for size reduction equipments and it is defined by breakage distribution function. Commonly, single particle breakage method is used to determine breakage behaviour of materials which assumes that breakage is not size dependent. As new surfaces formed material behaviour changes so particle size effect should also be introduced into the grinding model structure. Determination of fine particle breakage becomes important. This will make models more reliable. With this aim a bed breakage method was developed for determination of fine particle breakage. In this study new breakage model is presented and effects of different breakage distribution functions on breakage rate and discharge function is investigated. The bed breakage test results are compared with single size drop-weight test results in the aspect of modeling. It was observed that, the breakage rate and discharge function variation by size indicates a characteristic change at fine size ranges compared to regular curve.     

Tracer studies and breakage testing in pilot-scale stirred mills

A tracer technique is used to provide parameters that describe mixing and breakage in stirred mills. The results are also used to test the accuracy of mixing and breakage models.Tracer studies have been undertaken using a 39-litre vertical Sala agitated mill and a 4-litre horizontal Netzsch mill. The experimental residence time distribution (RTD) of the mills is analysed both in terms of a single mean residence time and a non-linear least squares fit to an optimal number of perf ect mixers of unequal size in series. Results show a strong dependence of RTD on flow rate, minimal dependence on stirrer speed, and support the concept that the RTD's of liquid tracers and solid tracers subject to breakage are similar. A very accurate match to the experimental RTD curves car be achieved with the multiple uneven mixers in series model.Size distribution results from solid tracer tests are used to determine the breakage characteristics of the pilot-scale Sala mill. The population balance model for a single perfect mixer with steady state hold-up is used as the basis for solution of a constrained non-linear optimisation inverse problem for mill breakage rate and breakage function. Experimental results indicate that the breakage rate is first order as hypothesised. The population balance model using optimal breakage parameters provides a reasonable fit to experimental data for cumulative passing percentage as a function of particle size for discrete times. Both the breakage rates and cumulative breakage functions are roughly power law dependent on particle size. Analysis of the size distribution of breakage products indicates that the mode of particle breakage, as indicated by the tracer breakage parameters, is a function of time. This demonstrates that the assumption of time independent breakage parameters in the population balance model may not be valid. Accurate determination of breakage parameters is strongly influenced by the transport characteristics of the slurry through the mill.The work shows that particle breakage in pilot-scale stirred mills is a complex function of both particle and specific mill characteristics. Therefore, in order to gain insight into the appropriate physical processes at work in an industrial scale mill, it is important to perform experiments with and analyse a system that matches the real mill as closely as possible.     

爆破模拟近场地震下顺层岩质边坡稳定性试验的理论研究

基于相似理论分析,探讨运用小尺度模型试验、用爆破模拟近场地震的方法考察顺层岩质边坡破坏的可行性。通过量纲分析发现,在模型试验设计中,通过控制模型大小来满足几何、形状参数缩比;通过选用相似材料,来控制波速比,密度比,进而从载荷、物性及形状上满足相似比关系,从理论上可实现爆破对近场高烈度地震的模拟。     

Fundamental batch mill model identification

The batch mill grinding equation can be described as being developed with respect to a control volume defined around the batch mill. However the advent of ball mill charge motion simulation using the discrete element method opens the door to determining the frequency of breakage events as well as the energy engaged therein. One can now envisage the development of a breakage model around the control volume defining the breakage event. In addition, one can postulate from first principles that an energy balance can be defined for this event along with a mass balance. In this paper, just such a hypothesis is formed and a fundamental batch mill model defined. Further, an identification procedure is proposed that allows model calibration from experimental data. Simulation results are compared with results obtained from the batch grinding equation using published parameters.     

Determination of the milling parameters of a platinum group minerals ore to optimize product size distribution for flotation purposes

Most concentrators desire to operate under optimal design configuration that guarantees high mineral recovery and low operational costs. The optimal design configurations are determined through studying the material to be milled in a laboratory mill under standard conditions. This is achieved through determining the selection and breakage function parameters and applying the mathematical simulation of the grinding process in order to optimize the size reduction process. The desired particle size is determined by the downstream processes, in our case, flotation. To this end, three mono-size classes feeds 850–600 μm, 600–425 μm and 425–300 μm of a platinum ore were ground using three different ball sizes (10, 20 and 30 mm) in a laboratory mill for the grinding times 0.5, 1, 2, 4, 8, 15 and 30 min. The data collected was used to determine breakage and some of the selection function parameters. The remaining parameters were back-calculated within the population balance model framework. The parameters were then used to obtain the product size distribution (PSD) that was later compared with the experimentally measured one. The milling kinetics for the desired size class for flotation was also simulated.There was a good match between the predicted and the experimentally measured PSD. The results of the milling done for further 60, 90, 120 and 240 min to validate the simulated milling kinetics from the determined parameters also showed good match between the simulated and the experimental one. This further confirms the validity of the determined parameters. From this, it becomes possible to determine the grinding conditions for optimal flotation.     

离散单元法在单颗粒物料单向压缩下的能耗研究

采用拟水平均匀设计方法,建立压板冲击速度、齿板厚度及上下两齿间水平距离三个因素的试验方案。结合离散元分析软件EDEM对单颗粒物料在单向压缩状态下的能耗及破碎概率进行数值模拟,并使用MATLAB对数值模拟结果进行回归分析,得到各因素对能耗及破碎概率的影响次序,为破碎机能耗计算提供依据。     

A performance model for impact crushers

In this paper we develop a performance model for impact crushers. The product size distribution is obtained as a function of the crusher’s rotor radius and angular velocity, the feed rate and the feed size distribution. The model is based on the standard matrix formulation that includes classification and breakage matrices. It can be applied to both hammer and vertical-axis impact crushers with the help of the corresponding estimations for the impact energy per unit mass.Here we propose classification and breakage functions for impact crushers taking into account the dynamic character of the impact breakage. The classification function has the form of a cumulative Weibull distribution and incorporates a minimum breakable size of the particles depending on the impact energy and the feed rate. The breakage function is modelled as the sum of two Broadbent–Callcott distributions. It is assumed to depend on the impact energy and the feed rate through the proposed expression for the proportion of the fine fraction in the product.The model predictions are compared with experimental data for limestone treated in a pilot-plant hammer crusher. The variations of the product size distribution resulting from changes in the rotor velocity and the feed rate are investigated.