闪锌矿精矿加压酸浸过程探讨

探索闪锌矿精矿高压酸浸的反应机理,制备一种相对纯净的闪锌矿,并在添加铁离子和不添加铁离子两种情况下对其进行高压酸浸试验.在浸出体系中没有铁元素时,闪锌矿浸出速度很慢.如在氧分压0.3MPa,温度160℃下浸出180min,锌的浸出率也仪有11.06%.在浸出体系中加人铁元素后,闪锌矿浸出速度加快了.在上述例子的条件下,锌的浸出率达到62.55%.然而,温度低于150℃,铁元素并没表现出对闪锌矿浸出的促进作用.锌的浸出速度曲线和亚铁离子氧化速度曲线的趋向是一致的,尽管两者不按比例变化.闪锌矿的浸出速度随着浸出体系中铁元素浓度的增大而不断增大,但当铁离子达到一定浓度后,闪锌矿的浸出速度不再有明显的增大.在一定的反应条件下,铁(或其他变价金属元素)的氧化是高压酸浸过程不可或缺的步骤,并且在一定范围内,铁离子的浓度决定了浸出的速度,对浸出机理进行了阐述.

Discussion on Pressure Acid Leaching of Sphalerite Concentrate

To investigate the reaction mechanism in high pressure acid leaching of sphalerite concentrate,artificial zinc sulfide crystal is prepared.Such relatively"pure"sphalerite concentrate is leached in a pressure autoclave,with or without iron ion added.Experimental results show that in the iron-absence leaching experiments,dissolution kinetics of sphalerite concentrate is very low,and even in the 180 min and 160℃ pressure acid leaching experiments,dissolution of zinc is only 11.06%.While in the iron-added experiments,dissolution kinetics is relatively high,and in the 180min and 160℃ high pressure acid leaching experiments,it is 62.55%.But such high kinetics csused by iron occurs only when the leaching temperature is 150℃ or above.Dissolution rate of zinc in sphalerite concentrate and oxidation rate of ferrous ion have the same trend in term of kinetics,though they do pot increase proportionally.Leaching kinetics of spalerite concentrate is greatly depended on the concentration iron ion,but there is an optimal one to achieve the highest kinetics:To some extent oxidation of ferrous ion is an indispensable step in HPAL.Within a range of certain concentration,leaching kinetics is determined by the concentration of ferric ion.The mechanism related to oxidation of ferrous ion is described.