Recovering metals from red mud by thermal treatment and magnetic separation

Abstract

This paper deals with an alternative treatment for recovering metals from goethite red mud (RM), which occurs as a by-product at zinc leaching plants. It is derived from the hydrometallurgical treatment of sphalerite, which involves roasting followed by acid attack and subsequent recovery of the zinc byelectrodeposition. The leaching mud contains various oxides and hydroxides of iron plus lesser amounts of sulfates ofPb, Zn, Ca, Cd, Ag, In, Se, and other metals. In recent years, numerous attempts have been made to recover the RM or render it inert, particularly by such processes as vitrification or lithification for the production of glass ceramics. The work reported here proposes a treatment involving reduction and magnetic separation to permit the extraction of pure zinc, a high percentage of a pure magnetite, and a harmless slag containing mixed silicates of zinc and lead as well as oxides of minor elements.

Synthesis and characterization of kaolinite coated with copper oxide and its effect on the removal of aqueous Lead(II) ions

“…As a remedial measure, these wastes are stored in sealed plastic tanks under reducing condition. This process stimulates the lowering of the concentration of metals and metalloid in the slurries and leaching mud before discharge into the aquatic environment (Plescia and Maccari 1996;Tavares et al 2017). This remedial process is dependent on the oxidation-reduction state of these metallurgical wastes and has substantial effect on the leaching of elements.…”