Evaluation of the Behavior of Trace Elements in Industrial Residual Materials under Pyrometallurgical Chlorine Treatment by Means of Algorithmic and Thermodynamic Simulations

An investigation of a selective chlorination approach of targeted elements from zinc and nickel residues is studied. Goethite and Jarosite are iron precipitated residues which result from the zinc and nickel industries, and they contain many valuable elements as well as heavy elements. The recycling of these elements is environmentally beneficial. The aims of this investigation were to recover the targeted valuable elements from the residues, and to explain the fundamentals of the chlorination process. In addition, the effects of using different chlorination agents, such as aluminum chloride hexahydrate, iron chloride hexahydrate, and magnesium chloride hexahydrate were studied. The study also examined the impact of using various stoichiometric amounts of these agents under different heating rates on the extraction efficiency of the targeted elements. The experiments were performed using a simultaneous thermal analysis machine to simulate a pyrometallurgical treatment, more than 120 experiments were completed using different experimental conditions and varying many parameters. The collected products of reaction were saved for further analysis. The gathered data was analyzed using a Python algorithm to plot the resulting thermal analysis curves and calculate the kinetics of the reaction. Scanning electron microscopy with the capability of energy dispersive X-ray spectroscopy was used to produce high magnification scans to examine the microstructure of the resulting materials, and to generate an element mapping to get a better idea about the chemical composition of the samples. The result of this work can be summarized using the best efficiency of extraction for the targeted elements and their optimum experimental configuration. Within this framework, magnesium chloride hexahydrate was constantly the most effective in the selective chlorination treatment and yielded the highest efficiencies of extraction for the targeted valuable elements, followed by iron chloride hexahydrate, while aluminum chloride hexahydrate was the least favorite. An analysis of variance was conducted in the final chapter of this work with the aim of determining the optimum configuration for the experiment and the significance of each of the experimental parameters.