Assessment Of Metal Recovery From Raw Spent Hydrodesulfurization Catalyst Through Bioleaching And Chemical Leaching

Assessment Of Metal Recovery From Raw Spent Hydrodesulfurization Catalyst Through Bioleaching And Chemical Leaching

Type	Journal Article
Author	P. F. Ferreira
Author	E. F. C. Sérvulo
URL	Free Full Text Source:  http://www.portalabpg.org.br/bjpg/index.php/bjpg/article/view/443
Volume	9
Issue	4
Pages	137-145
Publication	Brazilian Journal of Petroleum and Gas
Date	2016-1-6
Abstract	The aim of this work is to evaluate the recovery of metals from a spent catalyst of diesel hydrodesulfurization (HDS), without any chemical, thermal, or physical pre-treatment, using the Acidithiobacillus thiooxidans FG-01 strain and chemical leaching. The spent catalyst is a hazardous waste due to the presence of organochlorine compounds, petroleum hydrocarbons, and heavy metals. Chemical leaching tests were performed with solutions of citric acid (20 g L-1), oxalic acid (20 g L-1), citric and oxalic acid mixture (1:1, 20 g L-1), and sulfuric acid (10 g L-1). The best results of metals recovery through chemical reaction were obtained when using the inorganic acid solution. The two-step bioleaching assays were conducted in 500 mL Erlenmeyer flasks, with a pulp density of 27.5 g L-1, and a sulfuric acid concentration of 20 g L-1. There were no differences between chemical and microbial leaching results. The A. thiooxidans FG-01 is a promising strain due to the recovery of Al (~65%), V (~25%), and Mo (~25%) from the raw solid residue.