低品位多金属铋矿的湿法浸出工艺及其基础理论研究

【作者】 吴绍华；

【导师】 兰尧中；

【作者基本信息】 云南师范大学 ， 物理化学， 2006， 硕士

【摘要】 本论文归纳了铋湿法冶金的国内外研究现状。针对个旧多金属铋矿中铋品位低（7.25％）、硫含量高（25.53％）的特点，以降低投资成本，提高矿产资源综合利用率，减小环境污染为目的，提出了一种用二氧化锰浸出的湿法浸出工艺流程。 在对铋浸出的热力学及浸出机理进行分析研究的基础上，考察了影响铋浸出率的诸多因素，低品位铋矿浸出受氧化剂种类、酸度、搅拌速度、矿物粒度、氯离子浓度、液固比、浸出时间、浸出温度等诸多因素的影响。实验中首先通过对影响浸出各因素的研究，确定最优化综合浸出条件：HCl起始浓度为4.0mol／L；800rpm的搅拌速度；氧化剂用量为1.5倍理论值用量；矿物粒度约为0.105-0.074mm；1.5mol／L的氯离子起始浓度；液固比为4：1；浸出时间为180min。此时综合浸出率可达96％以上。 本文还研究了低品位铋矿浸出的化学反应动力学模型。从动力学的角度分析了整个浸出过程，结果表明，浸出过程符合缩小核模型1-（1-η）^1/3=kt，通过Arrhenius经验公式，由不同温度下的Ink-1/T图，求得活化能为56.868kJ／mol。浸出反应的速率常数与粒度直径的倒数呈线性关系，说明浸出属于化学反应控制。浸出的动力学方程为： 利用从钢渣通过磁选回收的铁粉对浸出液进行置换，置换体系中，置换速率明显受到Bi³⁺初始浓度、温度、溶液pH及搅拌速率的影响。比较适宜的置换条件是：温度为25℃，溶液pH范围在-1.0～0.5之间，搅拌速率为400rpm，Cl^-浓度＜1.5mol／L，置换时间为60min。在此条件下，铋的置换率可达99％以上。通过Arrhenius图，计算得到了该置换反应得活化能E_a=14.61kJ／mol；反应机理符合扩散控制机理；动力学数据服从一级反应的规律。更多还原

【Abstract】 The current situation of leaching of bismuth from the low-grade mineral was summed up. The low grade complex multi-metal bismuth ore used in this experiment contains 7.25 percent of bismuth and 25.53 percent of sulfur. The purpose of this experiment was to probe a new hydrometallurgical approach to extract bismuth from the low grade and complex multi-metal sulfide ores at high recoveries but low costs, low pollution by MnO₂Based on the analysis of thermodynamics and mechanism of the leaching process, laboratorial-scale experiments about new technology had been invested systematically in this paper under normal pressure and room temperature. The optimum conditions we obtained as follows: concentration of hydrochloric acid=4.0 mol/L, stirring speed=800 rpm, particle size=0.105-0.074 mm, concentration of sodium chloride=1.5 mol/L, solid/liquid ratio=1:5, leaching time=180 min. Under the optimum conditions, the comprehensive leaching rate is more than 96%.The kinetics of leaching bismuth from low grade and complex multi-metal sulfide ores was also investigated. Results showed that the leaching process canbe simulated with a shrinking core model 1- （1-η）^1/3 = kt. The activation energy calculated according to the Arrhenius equation was 56.868 kJ/mol. There was a linear relation between the apparent rate constant and the reciprocal of the mean particle diameter. The results of kinetic analysis of the leaching data under various experimental contions indicated a reaction controlled by the solution transport of protons through the product layer; the following rate equation was established:The cementation of bismuth on iron powder from solutions had been studied. Iron powder used in this experiment was recycled from steel slag by magnetic separation method. The influence of several parameters on the course of the更多还原