title: Recovery of water and acid from leach solutions using direct contact membrane distillation.
abstract: This paper describes for the first time the use of direct contact membrane distillation (DCMD) for acid and water recovery from a real leach solution generated by a hydrometallurgical plant. The leach solutions considered contained H2SO4 or HCl. In all tests the temperature of the feed solution was kept at 60 °C. The test work showed that fluxes were within the range of 18-33 kg/m(2)/h and 15-35 kg/m(2)/h for the H2SO4 and HCl systems, respectively. In the H2SO4 leach system, the final concentration of free acid in the sample solution increased on the concentrate side of the DCMD system from 1.04 M up to 4.60 M. The sulfate separation efficiency was over 99.9% and overall water recovery exceeded 80%. In the HCl leach system, HCl vapour passed through the membrane from the feed side to the permeate. The concentration of HCl captured in the permeate was about 1.10 M leaving behind only 0.41 M in the feed from the initial concentration of 2.13 M. In all the experiments, salt rejection was >99.9%. DCMD is clearly viable for high recovery of high quality water and concentrated H2SO4 from spent sulfuric acid leach solution where solvent extraction could then be applied to recover the sulfuric acid and metals. While HCl can be recovered for reuse using only DCMD.
authors.affiliation: Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University, P.O. Box 14428, Melbourne, Vic 8001, Australia E-mail: uchennakennedy.kesieme@live.vu.edu.au; CSIRO, Process Science and Engineering/CSIRO Minerals Down Under National Flagship, Australia, P.O. Box 7229 Karawara, WA 6152, Australia.
authors.forename: Uchenna K
authors.initials: UK
authors.lastname: Kesieme
authors.affiliation: Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University, P.O. Box 14428, Melbourne, Vic 8001, Australia E-mail: uchennakennedy.kesieme@live.vu.edu.au.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Milne
authors.affiliation: CSIRO, Process Science and Engineering/CSIRO Minerals Down Under National Flagship, Australia, P.O. Box 7229 Karawara, WA 6152, Australia.
authors.forename: Chu Yong
authors.initials: CY
authors.lastname: Cheng
authors.affiliation: Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University, P.O. Box 14428, Melbourne, Vic 8001, Australia E-mail: uchennakennedy.kesieme@live.vu.edu.au; Jervois Mining Limited, 10 Jamieson Street, Cheltenham, Vic 3192, Australia.
authors.forename: Hal
authors.initials: H
authors.lastname: Aral
authors.affiliation: Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University, P.O. Box 14428, Melbourne, Vic 8001, Australia E-mail: uchennakennedy.kesieme@live.vu.edu.au.
authors.forename: Mikel
authors.initials: M
authors.lastname: Duke
mesh_terms: D000143:Acids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D008567:Membranes, Artificial; D008669:Metallurgy; D013464:Sulfuric Acids; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D014867:Water / Q000737:chemistry*; D018508:Water Purification
chemical_list: D000143:Acids; D007220:Industrial Waste; D008567:Membranes, Artificial; D013464:Sulfuric Acids; D014867:Water; C033158:sulfuric acid