Extração por solventes aplicada à remoção de metais pesados presentes no licor de lixiviação do minério de manganês da Mina do Azul (PA)

Abstract

O objetivo desse trabalho foi promover o tratamento hidrometalúrgico do licor de sulfato de manganês proveniente da lixiviação do minério de manganês da Mina do Azul (PA), através da remoção de cobre, níquel, cobalto e ferro presentes em solução, via extração por solventes. Foi empregado o CYANEX302® como extratante orgânico solubilizado em Exxsol D-100®. Os resultados obtidos para o sistema CYANEX302® em Exxsol D-100® foram satisfatórios, alcançando percentuais individuais de extração de 98% de zinco, 92% de níquel e 77% para o ferro, enquanto mais de 90% de manganês permaneceu em solução. Nas condições de máxima extração conjunta de impurezas metálicas e mínima extração de manganês, isto é, porcentagem de CYANEX302® na fase orgânica igual a 6,0%, tempo de contato entre as fases igual a 3 minutos e relação fase orgânica e fase aquosa igual a 5,5, os resultados experimentais obtidos mostraram que 3,7% de manganês foram extraídos conjuntamente com 77,1% de ferro, 89,7% de zinco e 31,3% de níquel.<br>The goal of this experimental work was to treat a manganese sulfate aqueous solution obtained from the sulfuric acid leaching of Mina do Azul manganese ore (Brazil) to remove copper, nickel, cobalt and iron by solvent extraction using CYANEX302® solubilized in Exxsol D-100®. The experimental results for the individualized extraction stage were considered satisfactory and reached 98% Zn, 92% Ni and 77% Fe, while more than 90% of manganese was kept in solution. The experimental conditions for maximum impurities extraction and minimum manganese extraction were 6.0% v/v CYANEX302® in the organic phase, 3 minutes of contact time between phases and an organic/aqueous phase ratio equal to 5.5. Under these conditions, the results were 3.7% extraction of manganese, 77.1% iron, 89.7% zinc and 31.3% extraction of nickel

Experimental Design in Solvent Extraction: A Study for Divalent Metals Separation in D2EHPA/Isoparaffin System

“…Solutions of sulfuric acid have been frequently used as a leaching agent for manganese, cobalt, nickel and copper ore. However, the dissociation of bisulfate ion into hydrogen and sulfate ion is incomplete and a thermodynamic analysis of the acid solution is not trivial [10][11][12][13][14][15][16][17][18][19][20]. Thus, within the process of divalent metals extraction by D2EHPA the aim was to evaluate the influence of four variables as: concentrations of metals (Mn, Co, Ni, and Cu) in the synthetic leach liquor, concentration of extractant D2EHPA, the A/O ratio and the final equilibrium pH upon the percentage of extraction of the metals studied, leading to defining the optimum ranges for operation of the process of solvent extraction systems as studied.…”