Abstract: Disposal of waste in the metallurgical industry has become a challenge. Heaps of gypsum from hydrometallurgical plants using sulphates media are growing and pose an environmental problem. The current investigation focuses on the use of disposed gypsum from hydrometallurgical plants for Nickel recovery from slag. Sulfurization tests were carried out at different temperatures ranging from 600⁰C to 1250⁰C. XRD, XRF, ICP-MS and SEM-EDS were used for characterization. A silica crucible was used as a container placed in a tube furnace under argon gas to enhance the reaction. Nickel and Copper content in the slag were 0.75 and 1.16% respectively. The major phases were fayalite, cuprospinnel and nickel oxide. Results showed that the recycling of gypsum from hydrometallurgical plants was beneficial and the increase in temperature favored to convert nickel oxide into sulphide. Peacks decomposition has proved a number of sulphides have formed. However, above 1100⁰C the sulfurization decreased.
Authors: Nurse Chauke, Michel Kalenga Wa Kalenga, and Willie Nheta
Keywords: Sulfurization, slag, CaSO4, Temperature