基于浮选矿浆/泡沫多相粘度调控的夹带脉石运动行为研究

Entrainment is the main mechanism responsible for the recovery of gangue materials when floating low grade ores, which has a notorious effect on the concentrate grade. Rheology within a flotation cell is one of factors that significantly affect entrainment but no conclusion has yet been reached as to how it results in variations in the entrainment recovery of gangue during flotation. As the rejection of gangue mainly occurs at the pulp/froth interface region in a flotation cell, this project therefore investigates the effect of slurry viscosity and froth viscosity in this region on the entrained gangue recovery (i.e. water recovery and the degree of entrainment) as well as the mechanism underpinning the observed effect by performing continuous flotation tests. The objective of the project is to develop a comprehensive understanding of flotation system rheology influencing the recovery of gangue by entrainment and a more sophisticated predictive entrainment model, which provides plant operators with information they can use to optimize their existing circuits and minimize entrainment in their flotation operations.

脉石夹带对贫杂难选金属矿浮选精矿品位有重要影响。研究浮选体系性质对脉石夹带行为的影响机制及调控是贫杂难选金属矿资源开发的重要内容。粘度是影响脉石夹带的重要因素，但矿浆/泡沫多相粘度对脉石夹带的作用机理及调控技术原型研究还较少。本项目以浮选过程中矿浆/泡沫相界面区域多相矿浆和泡沫粘度与夹带脉石运动行为为主要研究对象，借助气动式叶片转子旋转流变仪，采用连续浮选系统，研究浮选环境下粘度对水回收率和脉石矿物夹带率的影响，通过斯托克斯定律和牛顿经典力学研究矿浆/泡沫相界面区域粘度调控环境下脉石矿物颗粒的运动行为，构建粘度与脉石矿物夹带率的定量响应关系，揭示浮选体系粘度对脉石夹带的影响规律及其作用机理，完善夹带模型，实现对脉石夹带的准确预测。项目将粘度对脉石夹带的作用机理研究由矿浆相扩展至矿浆/泡沫多相体系，为降低脉石夹带，提高贫杂难选金属矿浮选精矿品位，构建高效浮选过程提供理论与技术支撑。

降低细粒脉石夹带是目前贫杂难选金属矿产资源高效分选的关键，而研究浮选体系流变性质对脉石夹带行为的影响机制及调控是降低脉石夹带的重要内容。本项目围绕黄铜矿浮选矿浆/泡沫相界面粘度与夹带脉石运动行为的相关性展开研究，探明了粘度增加可显著降低水回收率、提高脉石夹带率，两者共同作用致使脉石回收率发生先升后降的变化规律。浮选动力学研究表明，粘度增加会降低浮选过程中黄铜矿浮选速率，恶化铜的回收，但浮选选择性呈现复杂波动变化。机理分析揭示了颗粒视重量与液流曳力共同决定了脉石颗粒的夹带行为，当粘度增大时，脉石颗粒受到的曳力呈指数型增大，导致脉石夹带率发生变化。脉石夹带率与μ^(-1) d^2 (δ-ρ)g的幂函数关系的解析，实证了相界面颗粒视重量与液流曳力的重要作用。基于此，构建了响应相界面粘度变化的夹带预测模型。研究还探索提出了优化浮选工艺如分级浮选或使用复配分散剂调控浮选体系粘度、降低脉石夹带的提质降杂方法。本项目对贫杂难选矿浮选过程中脉石夹带的预测与控制、分选效率的提高有一定的指导意义。