Abstract The effect of a thermal pretreatment on the kinetic parameters and rate-controlling step for nickel leaching dissolution in hydrochloric acid‑sodium chloride solutions from a low – grade Colombian nickel laterite (1.15% Ni, 0.12% Co and 41.1% Fe), was evaluated. The mineralogical analysis showed that nickel is associated with iron in the form of hematite (Fe2O3) and goethite (FeOOH) within the calcined and uncalcined ore, respectively. The hydrochloric acid and total chloride ions concentrations, as well as the leaching temperature, were shown to have a direct effect on nickel extraction. The experiments showed that ~92% of nickel can be dissolved after only 25 min in a 3 M HCl and 2 M NaCl solution when the leaching temperature was increased to 60 °C, after the sample had been previously calcined at 430 °C for 1 h. Nickel dissolution can be described by the chemical reaction-controlled shrinking particle model for both the calcined and uncalcined sample with apparent activation energies of 98 kJ/mol and 103 kJ/mol, respectively. This result suggests that a thermal pretreatment stage does not affect the nickel reaction mechanism, although it may liberate the nickel within the laterite structure.

中文翻译：

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热预处理对褐铁矿红土矿在氯化物介质中溶解动力学的影响

摘要 热预处理对来自低品位哥伦比亚红土镍矿（1.15% Ni、0.12% Co 和 41.1% Fe）的盐酸-氯化钠溶液中镍浸出溶解动力学参数和速率控制步骤的影响是评估。矿物学分析表明，镍分别与煅烧和未煅烧矿石中的赤铁矿 (Fe2O3) 和针铁矿 (FeOOH) 形式的铁结合。盐酸和总氯离子浓度以及浸出温度对镍提取有直接影响。实验表明，在 3 M HCl 和 2 M NaCl 溶液中，当浸出温度升高到 60 °C 时，约 92% 的镍可以在 25 分钟后溶解，此前样品在 430 °C 下煅烧 1 H。对于煅烧和未煅烧样品，镍溶解可以通过化学反应控制的收缩粒子模型来描述，表观活化能分别为 98 kJ/mol 和 103 kJ/mol。该结果表明，热预处理阶段不会影响镍反应机制，尽管它可能会在红土结构中释放镍。