针对碳酸盐脉石对氧化铜矿酸浸动力学的影响进行探讨,研究了温度、酸度、矿石粒径、液固质量比、振荡速度等因素对含碳酸盐脉石氧化铜矿浸出的影响.结果表明,高温、高酸度、高液固质量比、小粒径和高振荡速度利于矿石的浸出,但碳酸盐脉石使得酸耗增加.考虑浸出成本确定合理的浸出条件为温度303 K、酸度35 g·L-1、矿石粒径0.074~0.125 mm、液固质量比3﹕1以及振荡速度180 r·min-1,浸出180 min后铜浸出率达53.6%.对浸出前后矿石表面形貌进行分析.结果显示碳酸盐脉石与酸反应后在矿石表面形成CaSO4·2H2 O沉淀,覆盖在颗粒表面,限制了矿石颗粒孔裂隙的发育.基于收缩未反应核模型对浸出动力学进行分析,发现碳酸盐脉石反应生成的沉淀阻碍了浸出反应,固体产物层扩散为浸出反应的控制步骤,反应的表观活化能为8.65 kJ·mol-1.
This article is focused on the leaching kinetic of copper oxide ore containing carbonate gangue. The effects of tempera-ture, acid concentration, particle size, liquid-to-solid ratio and stirring rate on leaching of the copper oxide ore were determined. The results show that high temperature, high acid concentration, high liquid-to-solid ratio, low particle size and high stirring rate benefit the copper leaching. However, the carbonate gangue leads to a high consumption of acid. In consideration of leaching cost, the proper leaching condition is the temperature of 303 K, acid concentration of 35 g·L-1 , particle size of 0. 074-0. 125 mm, liquid-to-solid ratio of 3﹕1, and stirring rate of 180 r·min-1 . After leaching for 180 min, the copper leaching rate reaches 53. 6%. The morphologies of the ore surface before and after leaching were investigated and the results reveal that the carbonate gangue dissolves in the acid solution and CaSO4·2H2 O precipitation forms on the ore surface, which limits the development of porosity and cracks. Based on the shrinking core model, the leaching kinetic was analyzed. It is found that the precipitation on the ore surface hinders the leaching reaction. The diffusion across the product layer is the rate-controlling step and the activation energy is determined to be 8. 65 kJ·mol-1 .