In our previous study, the mineral evolution and porous kinetics during nitric acid pressure leaching of limonitic laterite has been investigated. In order to optimize the nitric acid leaching technology, this paper investigated the dissolution behavior and porous kinetics of limonitic laterite during nitric acid atmospheric leaching. The experimental results showed that Ni and Fe had consistent leaching behavior, whereas Co was only consistent with Mn in the early stages of leaching. The DFT (Density functional theory) simulations of goethite dissolution revealed that H⁺ attacked the bridging O first with adsorption energy of −1.37 eV, while NO₃^– attacked the Fe with adsorption energy of −3.07 eV, hence promoting the dissolution of Fe from the goethite crystals. Based on meticulous modeling analysis, the leaching of Ni could be described by grain model-cylindrical particle. In the early stage of leaching, the Ni extraction is regulated by chemical reactions with an activation energy of 88.4 kJ/mol. In the latter stage, the leaching is regulated by pore diffusion with an effective diffusivity of 1.37 × 10^-11 m²/min at 90 °C. This study clarified the dissolution behavior of limonitic laterite, and described nickel leaching using a porous kinetic model.

在我们之前的研究中，研究了褐铁矿在硝酸压力浸出过程中的矿物演化和多孔动力学。为了优化硝酸浸出工艺，本文研究了硝酸常压浸出过程中褐铁矿的溶解行为和多孔动力学。实验结果表明，Ni和Fe具有一致的浸出行为，而Co仅在浸出早期与Mn一致。针铁矿溶解的 DFT（密度泛函理论）模拟表明，H ⁺首先以 -1.37 eV 的吸附能攻击桥接 O，而 NO ₃ ^-以-3.07 eV的吸附能攻击Fe，从而促进Fe从针铁矿晶体中溶解。基于精细的建模分析，Ni的浸出可以用颗粒模型-圆柱颗粒来描述。在浸出初期，Ni 的提取受化学反应调节，活化能为 88.4 kJ/mol。在后期，浸出受孔隙扩散的调节，90℃时有效扩散率为1.37×10 ^-11 m ^{2 /min。}本研究阐明了褐铁矿红土的溶解行为，并使用多孔动力学模型描述了镍浸出。