溶液电位及堆结构影响次生硫化铜矿生物堆浸的动力学

来源期刊：中南大学学报(自然科学版)2006年第6期

论文作者：李宏煦 苍大强 邱冠周 吴爱祥

文章页码：1087 - 1093

关键词：生物冶金;细菌浸出;堆浸;次生硫化铜矿;溶液电位;动力学

Key words：biohydrometallurgy; bioleaching; heap leaching; secondary sulfide; solution potential; kinetics

摘    要：基于堆中溶液Fe³⁺与Fe²⁺的浓度比、颗粒空隙度、颗粒半径与各化学反应组分对次生硫化铜矿生物堆浸的影响,建立堆浸过程硫化矿细菌氧化反应速率动力学模型。计算与实验结果表明:模型仿真结果与实际结果较符合;堆浸过程次生硫化铜矿(辉铜矿)的氧化分为2个阶段,其中,辉铜矿反应步骤Ⅰ受溶液Fe³⁺浓度控制,随着Fe³⁺浓度增加,反应速率加快;反应步骤Ⅱ较反应步骤Ⅰ慢,为浸出反应的限制性步骤, Fe³⁺与Fe²⁺的浓度比是影响该反应步骤的关键因素。由于受扩散的限制,反应物颗粒粒径的增大导致浸出速率下降,但粒径过小时浸出率提高不明显。当喷淋强度由3.47/(m²·h)增加到69.00/(m²·h)时,浸出率逐渐下降,说明喷淋强度过大时,造成空隙间流体与颗粒孔道流体间界面剪切力过大,不利于物质传输与交换;当堆过高时,堆中离子的传输受阻,不利于次生硫化铜矿的浸出。

Abstract: Based on the concentration ratio of ferric to ferrous, ore particle interstice, ore particle size, heap construction and other chemical components, the kinetic model of the secondary copperheap bioleaching was proposed. The results show that during bioleaching the chalcocite decom posed by two stages, the stageⅠis controlled by the concentration of ferric, with the increase of ferric concentration the oxidation rate of chalcocite is enhanced. The rate of stageⅡis slower than that of the stageⅠand it acts as the confining stage, and the concentration ratio of ferric to ferrous influences the oxidation rate at this stage. By the diffusion confining of substance, the size increase of sulfide ore particle could slow down the oxidation rate, but too small size has not evident effect on improving the reaction rate. When the irrigating intensity increases from3.47/(m²·h) to 69.00/(m²·h), the reaction rate shows a gradual decrease, and the excessively high irrigating density would result in the high shearing strength of the solution between ore space and particle hole. The great heap height would also hamper the reaction components transfer and slow down the leaching rate.

基金信息：国家自然科学基金资助项目