Abstract A closed-loop, Ni extraction and mineral carbonation process is being developed for producing Ni from laterite ores, where the only inputs are heat that can come from regenerable resources, and the ore. This closed-loop relies on efficient regeneration of acid and base, which are required for leaching and neutralisation respectively. This contribution investigates the leaching efficacy of regenerated acid, and proposes a novel combined leaching and acid regeneration (CLR) process where the ore is present during the acid regeneration. It is hypothesised that this will favour the recovery of acid and base, and improve leaching kinetics. Results showed that the CLR process effectively shifted the equilibria to favour the production of acid. The feed solution of triethylammonium sulphate was formed by mixing 120 mmol H+ in the form of sulphuric acid (H2SO4) and 140 mmol triethylamine (Et3N). After 30 h 38 mmol of protons were regenerated in the CLR process compared to 30 mmol of protons being produced in the same timeframe during acid regeneration alone. The CLR was approximately twice as selective towards Mg and Ni over Al and Fe than leaching with the regenerated acid. However, the CLR process was not effective at increasing the recovery of base, with 60 mmol of Et3N recovered in both cases. The results show that the CLR process has the potential to reduce the acid requirements for leaching nickel laterites, which could improve the sustainability of metallurgical operations.

中文翻译：

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镍萃取-矿物碳酸化工艺的开发：使用再生酸的浸出机理分析

摘要 正在开发一种闭环、Ni 提取和矿物碳酸化工艺，用于从红土矿石中生产 Ni，其中唯一的输入是来自可再生资源的热量和矿石。这种闭环依赖于酸和碱的有效再生，分别是浸出和中和所必需的。该贡献研究了再生酸的浸出效率，并提出了一种新的浸出和酸再生 (CLR) 联合工艺，其中矿石在酸再生过程中存在。据推测，这将有利于酸和碱的回收，并改善浸出动力学。结果表明，CLR 过程有效地改变了平衡，有利于酸的产生。三乙基硫酸铵的进料溶液是通过混合120 mmol 硫酸(H 2 SO 4 )形式的H + 和140 mmol 三乙胺(Et 3 N)而形成的。30 小时后，在 CLR 过程中再生了 38 mmol 质子，而在同一时间段内仅在酸再生过程中产生了 30 mmol 质子。与用再生酸浸出相比，CLR 对 Mg 和 Ni 的选择性大约是 Al 和 Fe 的两倍。然而，CLR 过程在提高碱回收率方面无效，在两种情况下都回收了 60 mmol Et3N。结果表明，CLR 工艺有可能降低浸出红土镍矿的酸要求，从而提高冶金操作的可持续性。30 小时后，在 CLR 过程中再生了 38 mmol 质子，而在同一时间段内仅在酸再生过程中产生了 30 mmol 质子。与用再生酸浸出相比，CLR 对 Mg 和 Ni 的选择性大约是 Al 和 Fe 的两倍。然而，CLR 过程在提高碱回收率方面无效，在两种情况下都回收了 60 mmol Et3N。结果表明，CLR 工艺有可能降低浸出红土镍矿的酸要求，从而提高冶金操作的可持续性。30 小时后，在 CLR 过程中再生了 38 mmol 质子，而在同一时间段内仅在酸再生过程中产生了 30 mmol 质子。与用再生酸浸出相比，CLR 对 Mg 和 Ni 的选择性大约是 Al 和 Fe 的两倍。然而，CLR 工艺在提高碱回收率方面无效，在两种情况下均回收了 60 mmol Et3N。结果表明，CLR 工艺有可能降低浸出红土镍矿的酸要求，从而提高冶金操作的可持续性。CLR 过程不能有效提高碱的回收率，在两种情况下都回收了 60 mmol Et3N。结果表明，CLR 工艺有可能降低浸出红土镍矿的酸要求，从而提高冶金操作的可持续性。CLR 过程不能有效提高碱的回收率，在两种情况下都回收了 60 mmol Et3N。结果表明，CLR 工艺有可能降低浸出红土镍矿的酸需求，从而提高冶金操作的可持续性。