Removal of arsenic from jarosite waste using hydrometallurgical treatment

Abstract

The jarosite waste used during this study consists of minute amount of arsenic that has a potential to be leached into environment when kept in open area. This study tried to recover arsenic from jarosite waste using hydrometallurgical treatment. The comprehensive characterization of jarosite samples was performed using various analytical techniques, including X-ray diffraction (XRD), Fourier transform Infrared (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX), and it was characterized as natrojarosite. For optimal removal of arsenic, the response surface methodology (RSM) was applied with the key factors, including dosage (A), time (B), temperature (C), and acid concentration (D) on the recovery of arsenic. The results indicated that the dosage (A) and acid concentration (D) demonstrated significant positive effects on arsenic recovery. As expected, the higher dosage and acid concentration was associated with increased recovery percentages for the arsenic from jarosite. Whereas time (B) and temperature (C) did not exhibit statistically significant recovery of arsenic within the specified experimental range. The contour plots showed the optimal operating conditions for the highest recovery percentage was approximately 52.61% when 2.5 g of jarosite was treated with 10 mol/L acid for 150 min at operating temperature of 80°. Although our study showed very moderate recovery of arsenic, it is first report where arsenic has been removed from jarosite waste. Readjustment of range of operating parameters would provide more insight into the further optimization of the yield.

Keywords: Acid treatment; Arsenic; Central composite design; Response surface methodology.