title: Manganese ore tailing: optimization of acid leaching conditions and recovery of soluble manganese.
abstract: Manganese recovery from industrial ore processing waste by means of leaching with sulfuric acid was the objective of this study. Experimental conditions were optimized by multivariate experimental design approaches. In order to study the factors affecting leaching, a screening step was used involving a full factorial design with central point for three variables in two levels (2(3)). The three variables studied were leaching time, concentration of sulfuric acid and sample amount. The three factors screened were shown to be relevant and therefore a Doehlert design was applied to determine the best working conditions for leaching and to build the response surface. By applying the best leaching conditions, the concentrations of 12.80 and 13.64 %w/w of manganese for the global sample and for the fraction -44 + 37 μm, respectively, were found. Microbeads of chitosan were tested for removal of leachate acidity and recovering of soluble manganese. Manganese recovery from the leachate was 95.4%. Upon drying the leachate, a solid containing mostly manganese sulfate was obtained, showing that the proposed optimized method is efficient for manganese recovery from ore tailings.
authors.affiliation: Instituto de Ciências Exatas e Biológicas, Departamento de Química, Universidade Federal de Ouro Preto - UFOP, 35400-000 Ouro Preto, MG, Brazil. Electronic address: santos.oliviash@yahoo.com.br.
authors.forename: Olívia de Souza Heleno
authors.initials: Ode S
authors.lastname: Santos
authors.affiliation: Instituto de Ciências Exatas e Biológicas, Departamento de Química, Universidade Federal de Ouro Preto - UFOP, 35400-000 Ouro Preto, MG, Brazil.
authors.forename: Cornélio de Freitas
authors.initials: Cde F
authors.lastname: Carvalho
authors.affiliation: Instituto de Ciências Exatas e Biológicas, Departamento de Química, Universidade Federal de Ouro Preto - UFOP, 35400-000 Ouro Preto, MG, Brazil.
authors.forename: Gilmare Antônia da
authors.initials: GA
authors.lastname: Silva
authors.affiliation: Instituto de Ciências Exatas e Biológicas, Departamento de Química, Universidade Federal de Ouro Preto - UFOP, 35400-000 Ouro Preto, MG, Brazil.
authors.forename: Cláudio Gouvêa Dos
authors.initials: CG
authors.lastname: Santos
mesh_terms: D048271:Chitosan; D007220:Industrial Waste / Q000032:analysis*; D008345:Manganese / Q000032:analysis / Q000302:isolation & purification*; D008863:Microspheres; D008906:Mining; D015999:Multivariate Analysis; D013054:Spectrophotometry, Atomic; D013464:Sulfuric Acids; D013818:Thermogravimetry; D013997:Time Factors
chemical_list: D007220:Industrial Waste; D013464:Sulfuric Acids; D008345:Manganese; D048271:Chitosan; C033158:sulfuric acid
keywords: Chitosan; Manganese ore tailing; Multivariate experimental designs