Removal of Arsenic from Waste Heat Boiler Dust of a Copper Plant by Solvent Extraction Using Undiluted Tributyl Phosphate

Abstract

In the present study, undiluted TBP was employed to separate arsenic from a typical leach liquor of a copper industry bearing 9.08 g/L As, 46.69 g/L Cu, 23.44 g/L Ni, 1.23 g/L Fe, 0.49 g/L Zn and 0.09 g/L Co by solvent extraction technique. The effect of different parameters such as extractant concentration, H2SO4 and HCl concentration and temperature on extraction of arsenic was examined. With increasing the concentration of sulfuric and hydrochloric acid in the leach liquor, the percentage extraction of arsenic was increased. However, with increasing the temperature, the percentage extraction decreased. The McCabe-Thiele plot indicated 4 counter current stages at A : O ratio of 1 : 4 for the quantitative extraction of arsenic. The loaded organic contained 2.26 g/L As and was stripped with water. The McCabe-Thiele plot for stripping showed 2 counter-current stages at A : O = 1 : 2 and the stripping efficacy was 99.3%. The thermodynamic parameters such as increment H & DEG;, increment G & DEG;, and increment S & DEG; were calculated for arsenic extraction. The enthalpy change ( increment H & DEG;) value was negative indicating the extraction processes was exothermic.