More than 70% of the world's nickel reserves are found in laterite ores. In this research, a laterite ore sample, containing Ni, Co, and Fe, was employed to study the recovery of nickel and cobalt. Thus, the effect of calcination, acid concentration, percent solids, and stirring rate on nickel and cobalt recoveries from an iron‐rich laterite sample was investigated. Optimization with response surface methodology and kinetic studies were performed. The calcination of the sample prior to leaching at 500°C for 2 h provided condition for better nickel and cobalt dissolutions. At optimal conditions, the concentration of sulfuric acid, solid‐to‐liquid ratio, stirring speed, temperature, and time test were equal to 5 M, 0.1, 370 rpm, 90°C, and 2 h, respectively. The highest recoveries of nickel and cobalt were 65.9% and 63.1%, respectively. Solids content had a negative effect on Ni and Co recovery, whereas acid concentration was positively affected. Addition of 10% (w/v) NaCl in the presence of 5 M acid concentration, 60°C, 370 rpm, and leaching time of 2 h increased the nickel and cobalt recoveries, 15.3% and 21.4%, respectively. The high dependence of process on temperature indicates chemical control; the activation energies E_a = 59.54 and E_a = 45.74 kJ/mol, respectively, for nickel and cobalt, were also consistent with this conclusion.

中文翻译：

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在常压下使用硫酸使富铁红土矿石中镍和钴的溶解优化和动力学

世界上超过70％的镍储量都来自红土矿石。在这项研究中，使用含有镍，钴和铁的红土矿石样品来研究镍和钴的回收率。因此，研究了煅烧，酸浓度，固体百分比和搅拌速率对富铁红土样品中镍和钴回收率的影响。用响应面方法和动力学研究进行了优化。样品在500°C浸出2 h之前进行煅烧，为镍和钴的更好溶解提供了条件。在最佳条件下，硫酸浓度，固液比，搅拌速度，温度和时间测试分别等于5 M，0.1、370 rpm，90°C和2 h。镍和钴的最高回收率分别为65.9％和63.1％。固含量对镍和钴的回收率有负面影响，而酸浓度受到正面影响。在5 M酸浓度，60°C，370 rpm和2 h浸出时间下添加10％（w / v）NaCl，镍和钴的回收率分别提高了15.3％和21.4％。工艺对温度的高度依赖表明了化学控制。活化能镍和钴的E _a  = 59.54和E _a  = 45.74 kJ / mol，也与该结论一致。