Leaching Of Hydrocarbon-Contaminated Mine Sludge Using Concentrated Chloride And Ozone Gas

The mining of PGM includes ore blasting using explosives and mechanized equipment. However, there are problems associated with mechanized equipment, which include equipment releasing hydrocarbons such as diesel, which contaminate the mine sludge. In this paper, an alternate hydrometallurgical technique for extracting PGMs from mine sludge was investigated by leaching PGM mine sludge with hydrochloric acid and ozone gas as an oxidizing agent. The particle size distribution of the mining sludge was determined using a Mictrotrac analyser, chemical composition using XRF, mineralogy using XRD, surface morphology using SEM, and hydrocarbon content using FTIR. The sample had a particle size distribution (PSD) of 80% passing 50 microns. The highest recoveries were 69.31% Pt, 23.33% Au, and 50.28% Pd. XRF analysis showed high concentrations of Si (27.46%), Fe (25.12%), and Cr (13.75%), with trace elements like Na, P, Ti, V, Mn, and Sr. XRD analysis identified minerals such as chromite, magnesioferrite, quartz, tridymite, aluminosilicates (anorthite, akermanite). FTIR analysis detected functional groups O-H, C-H, and N-H, indicating the presence of hydrocarbons like alcohols, alkanes, and amines. SEM analysis revealed PGMs embedded in a matrix of quartz, chromite, magnesioferrite, and tridymite, often situated between silicate and chromite-based minerals. These findings suggest that hydrometallurgical leaching could serve as a viable approach for PGM recovery from contaminated mine sludge, warranting further optimization and investigation.