Assisted reagents are commonly introduced into acid leaching systems to improve metal recovery. In this work, fluorite was employed to accelerate magnesium (Mg) dissolution from serpentine tailings, and the dissolution mechanism was investigated by leaching experiments, kinetics equations and reaction analyses. The effects of fluorite powder dosage, particle size, reaction temperature, sulfuric acid concentration, and agitation speed on the efficiency of magnesium leaching were comprehensively studied. The results showed that the Mg leaching efficiency increased 36.42% after adding fluorite, reaching 93.69%. A shrinking-core model could be applied to adequately describe the leaching kinetics, and the Mg dissolution was controlled by the mixing rate with a calculated apparent activation energy of 38.698 kJ·mol⁻¹. In addition, a kinetics equation describing the leaching process was established as follows: 1/3ln(1-x)-1 + (1-x)^-1/3 = 70.372P^-1.071C^3.17S^0.497e^{-38,698.968/RT}t. Introducing the fluorite powder markedly decreased the ∆G^Θ of serpentine disintegration process; these phenomena was attributed to the complexation of F⁻ (fluorite) with Si⁴⁺ (serpentine). Therefore, this paper proposed an effective and inexpensive reagent for application in acid leaching processes.

通常将辅助试剂引入酸浸系统中以提高金属回收率。在这项工作中，萤石被用来加速蛇纹石尾矿中镁的溶解，并通过浸出实验，动力学方程和反应分析研究了其溶解机理。全面研究了萤石粉的用量，粒度，反应温度，硫酸浓度和搅拌速度对镁浸出效率的影响。结果表明，加入萤石后，镁的浸出效率提高了36.42％，达到93.69％。可以使用收缩核模型来充分描述浸出动力学，并且通过混合速率控制镁的溶解，计算出的表观活化能为38.698 kJ·mol ^-1。另外，描述浸出过程的动力学方程建立如下：1 / 3ln（1-x）-1 +（1-x）^-1/3  = 70.372P ^-1.071 C ^3.17 S ^0.497 e ^{-38,698.968 / RT} t 。萤石粉末引入显着降低的ΔG ^Θ蛇形崩解过程的; 这些现象是由于F的络合^- （萤石）有Si ⁴⁺（蛇形）。因此，本文提出了一种有效且廉价的试剂，用于酸浸工艺。