Comparison of partial roasting and alkaline sulfide leaching for treatment of As-rich concentrates

Copper possesses a variety of applications. With regard to the primary copper production, enriched sulfidic copper concentrates are fed to the smelters. Within the last decades the copper concentration in usable ores/concentrates is decreasing. Concentrate content in impurities like arsenic, antimony, bismuth and other hazardous elements, which are mineralogically bonded, is on the rise. In addition to the state of the art partial roasting process, the removal of arsenic through alkaline sulfide leaching of respective copper concentrates is a viable option. Mineralogical and chemical compositions of arsenic-bearing concentrates are measured by PXRD, XRF and AES. The particle based mineralogy of examine concentrates is characterized by MLA. Moreover, fluid bed roasting and under nitrogen/oxygen atmosphere are conducted to examine operational parameters on arsenic removal with focus on the oxygen partial pressure. For the hydrometallurgical part leaching tests with a sulfide solution under alkaline conditions are conducted in a lab scale reactor allowing for direct process comparison.