Leaching kinetics and stoichiometry of pyrite oxidation from a pyrite-marcasite concentrate in acid ferric sulfate media
Leaching kinetics and stoichiometry of pyrite oxidation from a pyrite-marcasite concentrate in acid ferric sulfate media
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DOI：
10.1016/j.hydromet.2006.05.008
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发表时间：
2006-11-01
期刊：
影响因子：
4.7
通讯作者：
Dixon, David G.
中科院分区：
文献类型：
--
作者：
Bouffard, Sylvie C.;Rivera-Vasquez, Berny F.;Dixon, David G.
在酸性硫酸铁介质中，在温度为45 ~ 75℃、铁（III）与铁（II）比为10 ~ 300的恒电位条件下氧化含少量马氏铁矿的黄铁矿精矿。高锰酸钾（KMnO4）是一种控制溶液电位的适宜氧化剂，也是一种方便可靠的浸出过程指示剂。发现黄铁矿氧化的化学计量学基本上与温度无关，在研究的条件范围内仅轻微依赖于溶液电位。每单位硫化物硫氧化产生64 +/- 2%的硫酸盐，其余单质硫为直径约2克的离散颗粒。黄铁矿的氧化速率对温度非常敏感，具有较大的活化能（83 kj/mol），且与Fe(III)/Fe（IT）浓度比成0.57的倍数。缩球模型很好地拟合了晶粒拓扑结构的变化。一个单一的数学表达式结合了热、化学和拓扑函数来预测黄铁矿转化作为已知温度、铁浓度、铁浓度、粒度和时间的函数。在测试的条件范围内，模型的预测是很好的。(C) 2006 Elsevier B.V.版权所有
A pyrite concentrate with minor marcasite was oxidized in an acidic ferric sulfate medium at temperatures from 45 to 75 degrees C and at constant potentials corresponding to Fe(III) to Fe(II) ratios from 10 to 300. Potassium permanganate (KMnO4) was found to be both a suitable oxidant for controlling the solution potential and a convenient and reliable indicator of leaching progress.The stoichiometry of pyrite oxidation was found to be essentially independent of temperature and only slightly dependent on solution potential over the range of conditions studied. Each unit of sulfide sulfur oxidized yielded 64 +/- 2% sulfate, the rest elemental sulfur as discrete particles approximately 2 gm in diameter.The pyrite oxidation rate was very sensitive to the temperature, giving a large activation energy (83 kj/mol), and was proportional to the Fe(III)/Fe(IT) concentration ratio to the power of 0.57. The shrinking sphere model fitted very well the changing grain topology. A single mathematical expression combines the thermal, chemical, and topological functions to predict the pyrite conversion as a function of the known temperature, ferric concentration, ferrous concentration, particle size, and time. The model predictions are excellent over the range of conditions tested. (C) 2006 Elsevier B.V. All rights reserved.