球磨介质及尺寸对铜锌矿矿浆化学性质及矿物表面化学性质的影响

Influence of ball mill medium and size on properties of copper-zinc ore pulp and mineral surface

采用飞行时间二次离子质谱仪和改良球磨机研究了磨矿环境对铜锌矿矿浆的化学性质和闪锌矿的表面化学性质的影响。通过采用改良后的球磨机实现磨矿过程中溶液p H、矿浆电位、电导率、溶解氧含量及离子浓度等矿浆化学性质的实时监测。随着磨矿时间的延长,矿浆p H值缓慢升高,矿浆电位和溶解氧含量迅速下降。结果表明:球形磨矿介质的直径越小,矿浆中溶解氧消耗越快,磨矿后矿浆静电位越低,矿浆的离子浓度也越低。飞行时间二次离子质谱仪对磨矿后闪锌矿的表面化学分析表明,磨矿后铁氧化物和氢氧化物会附着于闪锌矿表面,球磨介质的材料与尺寸大小对矿物表面存在的二次离子有较大影响。分别与不锈钢球或者2.54 cm的大球相比,铸铁球或1.27 cm的小球可为矿浆提供更多的铁离子,促进磨矿环境下的电化学反应,从而在闪锌矿表面累积更多的铁氧化物或氢氧化物,降低铜离子的吸附。因此,矿浆化学性质和闪锌矿的表面化学性质受磨矿介质的材料与介质的尺寸控制。

This study focuses on the influence of ball mill medium and size on the properties of copper-zinc ore pulp and mineral surface by time-of-flight secondary ion mass spectrometry(TOF-SIMS) and special designed grinding ball mill were applied.The p H,ORP(oxidation-reduction potential),conductivity and dissolved oxygen during grinding were monitored with redesigned chamber.The results show that,with grinding time prolonging,p H gradually increases,while dissolved oxygen content and ORP decrease rapidly.Smaller diameter of spherical grinding medium will result in greater consuming rate of the dissolved oxygen content,whereas lower ORP and pulp ions concentration.Surface chemistry analysis TOF-SIMS was performed on mill discharged sphalerite.It demonstrates that the formation of iron oxide and hydroxide species on sphalerite surface,as well as different types and different sizes of grinding medium can affect the mineral surface.Compared with spherical grinding diameter of 2.54 cm,diameter of 1.27 cm could supply more iron ions for pulp and improve electricity reactions during grinding,thus leading to the formation of more iron oxide and hydroxide species on sphalerite surface and lower adsorption of cupric ions(Cu2+).The same is also true for mild steel compared with stainless steel.From above,the pulp and sphalerite surface chemistry are decided by the types and sizes of grinding medium.