Marzoughi Omid, Pickles Chris, Ghahreman Ahmad
Robert M. Buchan Department of Mining, Queen's University, Kingston, ON K7L 3N6, Canada.
Heliyon. 2023 Jan 20;9(1):e13112. doi: 10.1016/j.heliyon.2023.e13112. eCollection 2023 Jan.
Elemental sulfur is one of the major byproducts of the acidic Albion leaching process for chalcopyrite. It is a challenging component in the leach solution as it impedes gold recovery from the residue. Lanxess Lewatit® AF 5 (AF 5) is a microporous carbon-based resin, which is being investigated for the removal of elemental sulfur during this leaching process. In the current research, a series of leaching experiments were performed as a function of temperature, agitation speed and concentrate to AF 5 ratio. Using these results, the adsorption isotherms, the kinetics and the thermodynamics of sulfur removal were studied. One hundred percent of the elemental sulfur could be adsorbed by the AF 5 resin from the acidic Albion leaching process for chalcopyrite. Adsorption isotherms at various temperatures were determined using the Langmuir and Freundlich models. The maximum sorption capacity of AF 5 at 95 °C was 488 mg/g. The kinetic data were fitted to pseudo-first order (PFO) and pseudo-second order (PSO) models and it was shown that the PFO model was best suited to describe the results. The rapid kinetics of sulfur adsorption were attributed to the open pore structure of the AF 5. The Gibbs free energy, enthalpy and entropy of sulfur adsorption by AF 5 were determined as follows: ΔG = -1.9 kJ/mol, ΔH = -9.1 kJ/mol, and ΔS = -0.1 kJ/(mol K). The negative free energy and enthalpy changes demonstrated that the adsorption of elemental sulfur was both spontaneous and exothermic over the temperature range studied.
元素硫是黄铜矿酸性阿尔比恩浸出工艺的主要副产品之一。它是浸出液中的一个具有挑战性的成分，因为它会阻碍从残渣中回收金。朗盛Lewatit® AF 5（AF 5）是一种微孔碳基树脂，目前正在研究其在该浸出过程中去除元素硫的性能。在当前的研究中，进行了一系列浸出实验，考察了温度、搅拌速度和精矿与AF 5的比例等因素的影响。利用这些结果，研究了硫去除的吸附等温线、动力学和热力学。AF 5树脂能够从黄铜矿的酸性阿尔比恩浸出液中吸附100%的元素硫。使用朗缪尔和弗伦德里希模型测定了不同温度下的吸附等温线。AF 5在95℃时的最大吸附容量为488 mg/g。将动力学数据拟合到伪一级（PFO）和伪二级（PSO）模型，结果表明PFO模型最适合描述实验结果。硫吸附的快速动力学归因于AF 5的开孔结构。AF 5吸附硫的吉布斯自由能、焓和熵分别为：ΔG = -1.9 kJ/mol，ΔH = -9.1 kJ/mol，ΔS = -0.1 kJ/(mol·K)。负的自由能和焓变表明，在所研究的温度范围内，元素硫的吸附是自发的且放热的。
