Alkaline sulphide leaching of tennantite in copper flotation concentrates to selectively dissolve arsenic

Abstract

High-arsenic copper flotation concentrates, in which the major arsenic-bearing mineral was tennantite, were leached with an alkaline sulphide system. At a pulp density of 5 wt% solids with 100-150 g/L Na 2 S and 50 g/L NaOH, over 91 wt% As was dissolved within 2 h at 100°C. From concentrates containing 3.4-4.9 wt% As, leach residues containing <0.5 wt% As were obtained making them suitable as a smelter feed without a penalty for arsenic. Copper dissolution ranged from 16 to 22 wt% Cu, with significant amounts of calcium, iron and sulphur also dissolved. In a leach at 34.0 wt% solids, excellent arsenic extraction was obtained (97.9 wt% As), but the levels of copper, calcium, and iron dissolution were 0.5, 1.1, and 0.2 wt%, respectively, meaning excellent selectivity for arsenic was achieved. X-ray diffraction and electron probe microanalyses indicated the mechanism for arsenic dissolution from tennantite, and bornite abundance in the residue.

Bioengineered Nanoparticle and Environmental Particulate Matter Toxicity: Mechanisms, Regulations and Applications

“…Either Arsenic or Stibium, Group 15 (semimetals), are bound to Sulfur (Group 16, nonmetal), and there is 91% dissolution of Tennantite at high temperature (212°F) over a 2 hour period in basic electrolyte solution (NaOH) containing Na 2 S [124]. The mined copper ore contains transition metals, Copper, Arsenic and Iron in polyhedral/ hextetrahedral configuration with some forms containing ionic free forms of Iron (Fe 3+/2+ ) and Zinc (Zn 2+ )(Table 1).…”

Purification of Copper Concentrate from Arsenic under Autoclave Conditions

“…In the era of industrial growth and development, enterprises involved in the processing of copper-arsenic raw materials are striving to modernize and optimize their technological processes. They make significant efforts to introduce more sophisticated and effective methods such as acid leaching [3][4][5][6], ammonia leaching [7], alkaline methods [8][9][10], bioleaching [11], and alternative methods [12][13][14][15]. However, all these innovations carry certain difficulties with them.…”