Article

Bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetics aspect.

Mineral and Material Processing Division, Korea Institute of Geosciences and Mineral Resources, Daejeon 305-350, South Korea.
Journal of Hazardous Materials (Impact Factor: 3.93). 05/2008; 152(3):1082-91. DOI: 10.1016/j.jhazmat.2007.07.083
Source: PubMed

ABSTRACT Bioleaching of metals from hazardous spent hydro-processing catalysts was attempted in the second stage after growing the bacteria with sulfur in the first stage. The first stage involved transformation of elemental sulfur particles to sulfuric acid through an oxidation process by acidophilic bacteria. In the second stage, the acidic medium was utilized for the leaching process. Nickel, vanadium and molybdenum contained within spent catalyst were leached from the solid materials to liquid medium by the action of sulfuric acid that was produced by acidophilic leaching bacteria. Experiments were conducted varying the reaction time, amount of spent catalysts, amount of elemental sulfur and temperature. At 50 g/L spent catalyst concentration and 20 g/L elemental sulfur, 88.3% Ni, 46.3% Mo, and 94.8% V were recovered after 7 days. Chemical leaching with commercial sulfuric acid of the similar amount that produced by bacteria was compared. Thermodynamic parameters were calculated and the nature of reaction was found to be exothermic. Leaching kinetics of the metals was represented by different reaction kinetic equations, however, only diffusion controlled model showed the best correlation here. During the whole process Mo showed low dissolution because of substantiate precipitation with leach residues as MoO3. Bioleach residues were characterized by EDX and XRD.

0 Bookmarks
 · 
103 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The dissolution kinetics of vanadium trioxide in sulphuric acid-oxygen medium was examined. It was determined that the concentration of sulphuric acid and stirring speed above 800 r·min−1 did not significantly affect vanadium extraction. The dissolution rate increased with increasing temperature and oxygen partial pressure, but decreased with increasing particle size. The dissolution kinetics was controlled by the chemical reaction at the surface with the estimated activation energy of 43.46 kJ·mol−1. The leaching mechanism was confirmed by characterizing vanadium trioxide and the dissolution residue using SEM-EDS analysis. Combined with thermodynamic calculation, the pressure leaching of vanadium trioxide in the temperature range (100 to 140 °C) studied occurs as follows: V2O3 + O2 + H2SO4 = (VO2)2SO4 + H2O.
    Rare Metals 31(3). · 0.49 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The dissolution kinetics of nickel laterite ore in aqueous acid solutions of three metabolic acids, i.e., citric acid, oxalic acid and acetic acid were investigated in a batch reactor individually. It was determined that experimental data comply with a shrinking core model. The diffusion coefficients for citric acid, oxalic acid and acetic acid were found to be 1.99×10-9 cm2/s, 2.59×10-8 cm2/s and 1.92×10-10 cm2/s respectively. The leaching ability of each acid was observed and it was found that oxalic acid was better than the other two.
    Brazilian Journal of Chemical Engineering 01/2011; Volume 28. · 0.89 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Research on biohydrometallurgy of secondary metal resources is primarily focussed on the leaching of valuable metals. For secondary metal resources biological processing can be an economically more effective and environmentally friendlier alternative to traditional hydrometallurgical and pyrometallurgical processes. Therefore, Bioydrometallurgy is a rapidly evolving biotechnology that has already provided revolutionary solutions to old problems associated with recovery of metals by conventional pyrometallurgy and chemical metallurgy. This review evaluates various pr ocesses of recovery of metals from waste materials and commercial applications are di scussed. Case studies and future technology directions are reviewed. Keywords: Biohydrometallurgy; Metal recovery; Recycling; Secondary metal resources
    Journal of Chemical Technology & Biotechnology 12/2013; 88(12):2115-2132. · 2.50 Impact Factor