CHARACTERIZATION AND THERMODYNAMIC STUDY OF SULFIDATION OF SECONDARY ALKALINE LEAD SLAG

Secondary alkaline lead slag, a major byproduct of lead smelting and lead-acid battery recycling, contains both valuable metals (Pb, Zn, Cu, Sn) and toxic elements (As, Cr, Sb), posing considerable environmental challenges while offering opportunities for metal recovery. Efficient recycling of this slag is crucial for minimizing environmental risks and maximizing resource utilization. This study investigates the sulfidation process as a promising metallurgical approach to selectively recover valuable metals while stabilizing hazardous elements. The research includes the physical and chemical characterization of the secondary alkaline lead slag and a comprehensive thermodynamic analysis to assess its thermodynamic properties and behavior within the examined system. Thermodynamic modeling was performed using HSC Chemistry® ver. 10, optimized key process parameters, including temperature, sulfur addition, and potential additives, to enhance recovery efficiency. The physical characterization of lead slag included measurements of bulk density, moisture content, and granulometric composition, while elemental composition was analyzed using X-ray fluorescence spectrometry (XRF) and inductively coupled plasma optical emission spectrometry (ICP-OES). Phase composition was determined via X-ray diffraction (XRD), and slag morphology was examined using scanning electron microscopy (SEM). The thermodynamic analysis confirmed the feasibility and effectiveness of the lead slag sulfidation, demonstrating favorable conditions for selective metal recovery and the stabilization of hazardous components.