【作者】 谢恒星；

【导师】 李松仁；

【作者基本信息】 中南大学 ， 矿物加工工程， 2002， 博士

【摘要】 本研究属原化工部科技发展计划项目“球磨机中钢球磨损机理与磨损规律的研究”（化科计发[1996]107号）和湖北省人事厅专家基金项目“湿式磨矿过程中助磨—缓蚀技术研究”（鄂人专字[2001]118号）中的重要内容。论文系统探讨了磨矿工艺条件、矿浆流变特性、磨矿电化学环境、助磨—缓蚀剂对钢球磨损的影响规律和作用机理：开发了旨在降低钢球磨损率、提高磨矿效率的助磨—缓蚀节能新技术，并在磷块岩浮选工业试验中得到了应用；在理论分析和试验研究的基础上，建立了钢球磨损规律的动力学模型和统计学模型，并在扩大连续性试验中进行了验证。 分别考查了磨矿方式、磨矿气氛、矿浆浓度、装球率等磨矿条件的变化对钢球磨损率和磨矿效率的影响规律。干式磨矿、湿式磨矿（水介质）和有机液介质磨矿条件下，钢球磨损率R增大的次序为R_有机＞R_湿式＞R_干式；磨矿产物中新增-0.043mm粒级产率F增大的次序为F_湿式＞F_有机＞F_干式。钢球的磨损率随磨机中氧气分压的增加而增大，研磨铁矿石时，增大的幅度较大：研磨石英岩和磷灰石矿时，增大的幅度较小。充氮气时研磨石英岩、铁矿石和磷灰石矿，钢球的磨损率依次减小。在有氧存在的条件下研磨铁矿石，由于其中的硫化矿物与钢球之间形成腐蚀电偶，从而加速了钢球的腐蚀磨损速度。钢球的磨损率在矿浆体积浓度约为25％时出现最大值；随着矿浆体积浓度的增大，磨矿产物中新增-0.043mm粒级的产率增大，但当矿浆体积浓度增大到50％以后反而略有下降。钢球的磨损率在装球率约为25％时出现最大值：随着装球率的增大，磨矿产物中新增-0.043mm粒级的产率增大，但是增大的幅度随装球率的增大而减小。 探讨了矿浆流变特性对钢球磨损行为的影响。矿浆的流变特性在矿浆体积浓度为50％时发生显著变化，即当矿浆体积浓度小于50％时，随着矿浆体积浓度的增大，矿浆粘度缓慢增加；当矿浆体积浓度大于50％时，矿浆粘度急剧增加，添加化学助剂能改善高浓度矿浆的流变性。矿浆粘度对钢球磨损率的影响存在一临界值(约为200 mPa.s，剪切速率22.4l s^-1)，当矿浆粘度处于临界值时，摘要钢球的磨损率出现最大值。钢球表面罩盖层厚度随矿浆体积浓度的增大而增大。当罩盖层厚度较小时，钢球的磨损率较大;随着罩盖层厚度的增大，钢球的磨损率减小，磨矿效率提高;当罩盖层厚度超过最佳值时，磨矿效率反而降低。 电化学实验结果表明，当钢球与黄铁矿接触时将形成腐蚀电偶，钢球的电位相对较负为阳极，黄铁矿的电位相对较正为阴极。黄铁矿与钢球电极之间在充氧气条件下的初始电位和电流大于充空气条件下的初始电位和电流，随着充气时间的延长，充氧气条件下的接触电位和电流下降的幅度比充空气条件下下降的幅度要大。模拟磨损差异电池实验结果表明，表面有磨损差异的钢球电极间有电流的存在，但比黄铁矿与钢球电极间的电流小。不同磨矿时间条件下，由钢球的腐蚀量根据法拉第定律计算得出的腐蚀电流密度与根据黄铁矿和钢球的极化曲线所获得的电偶腐蚀电流密度基本接近，但是总是大于根据极化曲线所获得的腐蚀电流密度值。X一射线衍射分析结果显示，钢球表面的腐蚀产物为a FeOOH和Fe，q的混合物。研究结果表明，钢球的腐蚀一磨损作用具有“同时性”、“交替性”和 “协同性”特征，即（l）腐蚀作用和磨损作用同时存在并分别遵循各自的作用规律;（2）腐蚀作用与磨损作用交替进行;（3）腐蚀作用与磨损作用相互促进。 助磨一缓蚀效应结果显示，在湿式磨矿中加入某种化学助剂，既能起到助磨剂的作用，又能起到缓蚀剂的作用。单一型助磨一缓蚀剂碳酸钠、硅酸钠、铬酸钠和复配型助磨一缓蚀剂铬酸钠一三聚磷酸钠、碳酸钠一硅酸钠具有良好的助磨一缓蚀作用，能明显提高磨矿效率、降低钢球磨损率。水玻璃对磷灰石矿的助磨作用具有选择性，即对磷酸盐类矿物的助磨作用比较显著，而对硅酸盐类矿物不存在助磨作用。在磷块岩浮选工业试验中，将部分碳酸钠和水玻璃加入磨矿过程中作为助磨一缓蚀剂，磨矿效率提高2%，钢球的磨损率降低12.7%，精矿中PZOS的回收率提高3.22%，企业每年直接经济效益将达到319.2万元。助磨一缓蚀效果的好坏可以用助磨一缓蚀效应评价函数F（x，y，z）来评判，如果△F>0，则说明存在助磨一缓蚀作用，△F值越大，助磨一缓蚀效果越好;反之亦然。 在湿式磨矿过程中，钢球的磨损符合迭加原理，即钢球的总磨损量为冲击磨中南大学博士学位论文湿式磨矿中钢球磨损机理与磨损规律数学模型的研究损量、磨剥磨损量和腐蚀磨损量之和，在此基础上建立了钢球磨损的动力学模型;在实验室磨矿条件下，对动力学模型参数进行了优化估计;扩大连续性试验结果表明，所建立的动力学模型真实地描述了钢球磨损的客观规律性o’以动力学模型为基础，通过理论分析和推导，建立了钢球磨损的统计学模型，并且通过实例，详细说明了统计学模型在合理补加钢球中的应用。 本研究的创新点在于: （1）论文系统探讨了磨矿工艺条件、矿浆流变特性、磨矿电化学环境、助磨一缓蚀剂对钢球磨损的影响规律和作用机理;开发了旨在降低钢球磨损率、?更多还原

【Abstract】 This dissertation is the main contents of the projects, Wear Mechanisms and Laws of Steel Balls in Ball Mill, [1996] 107 supported by the Developmental Program of Science and Technology of the Ministry of Chemical Industry of China, and the Aiding Grinding-Inhibiting Corrosion Technique in Wet Grinding, [2001 ] 118 by the Specialist Foundation of the Personnel Department of Hubei Province, China. Effects of different grinding conditions, slurry rheological behaviors, electrochemical aspects and chemical additiVes on the wear of steel balls in wet grinding are systematically studied. A new technique of aiding grinding-inhibiting corrosion is developed to reduce the wear rate of steel balls and raise the grinding efficiency. It is applied in industrial test of phosphate ore flotation. A dynamic model and a statistical model of the wear of steel balls are established on the basis of theories and experiments. The models are examined to be satisfactory with trial data.Effects of such grinding conditions as grinding way, grinding atmosphere, pulp volume density and charge volume on the wear rate of steel balls and the grinding efficiency are respectively investigated in this thesis. Test results show that the wear rate of steel balls R is arranged in order: Rorganic>Rwet>Rdry, the net mass fraction of -0.043mm size in grinding products F: Fwet>Forganic>Fdry under different conditions, namely dry, wet and in the presence of an organic liquid. The wear rate increases more rapidly in grinding iron ore than in grinding quartzite or phosphorus ore as the oxygen partial pressure in the mill is increased. It decreases in order of grinding quartzite, iron ore and phosphate ore under nitrogen flushing condition. In the presence of oxygen (oxygen or air flushed into the mill), the corrosive wear of steel balls accelerates in grinding iron ore due to form galvanic coupling between sulfide minerals in iron ore and steel balls. The wear rate increases with either of the pulp volume density and the ball charge, and reaches a maximum at about 25%. The net mass fraction of -0.043mmIVmaterial produced also increases with either of the pulp volume density and the ball charge, but it decreases slightly over pulp volume density of 50% and its growth speed decreases as the charge volume increases.Effects of slurry rheological characteristics on the wear performance of the balls are studied. Test results indicate that slurry rheological behaviors change outstandingly at pulp volume density of approximately 50%. Pulp viscosity increases gradually with pulp volume density under 50%, and does rapidly over 50%. The slurry rheological behaviors can be improved by adding some chemical additives into pulp with high volume density. The wear rate increases with pulp viscosity, and reaches a maximum at a critical viscosity of about 200mPa.s with a shear rate of 22.4Is"’.A law that the thickness of pulp layer coating on the balls varies with pulp volumetric solids content is found. The wear rate of steel balls with small pulp layer thickness is higher. The wear rate decreases and the grinding efficiency increases as the thickness increases, but the grinding efficiency decreases when it is over the best thickness.Electrochemical determining data demonstrate that the galvanic couples form between the pyrite particles and the steel balls when they contact with each other, because the rest potential of the steel ball electrode as an anode is lower and that of pyrite electrode as a cathode is higher. The initial combination potential and the initial galvanic current of a pyrite-steel ball couple in aeration of oxygen are greater than those in aeration of air. The combination potential and the galvanic current decrease more quickly with time in aeration of oxygen than they do in aeration of air. In an experiment of simulating wear differences, between two different balls in wear degree exists a galvanic current, which is smaller than that between pyrite and the ball. Under different grinding time conditions, the equivalent corrosion currents calcula更多还原