Accelerating Copper Leaching from Sulfide Ores in Acid-Nitrate-Chloride Media Using Agglomeration and Curing as Pretreatment

• Published in: Minerals (Basel) Vol. 9; no. 4; p. 250
• Main Authors: Pía C. Hernández, Junior Dupont, Osvaldo O. Herreros, Yecid P. Jimenez, Cynthia M. Torres
• Format: Journal Article
• Language: English
• Published: MDPI AG 01-04-2019
• Subjects: agglomeration; chalcopyrite; chloride; copper sulfide; curing; nitrate; pretreatment
• ISSN: 2075-163X
• DOI: 10.3390/min9040250

This work investigates the effect of an agglomeration and curing pretreatment on leaching of a copper sulfide ore, mainly chalcopyrite, using mini-columns in acid-nitrate-chloride media. Ten pretreatment tests were conducted to evaluate different variables, namely the addition of nitrate as NaNO3 (11.7 and 23.3 kg/ton), chloride as NaCl (2.1 and 19.8 kg/ton), curing time (20 and 30 days) and repose temperature (25 and 45 °C). The optimum copper extraction of 58.6% was achieved with the addition of 23.3 kg of NaNO3/ton, 19.8 kg of NaCl/ton, and after 30 days of curing at 45 °C. Under these pretreatment conditions, three samples of ore were leached in mini-columns. The studied parameters were temperature (25 and 45 °C) and chloride concentration (20 and 40 g/L). The optimum copper extraction of 63.9% was obtained in the mini-column leaching test at 25 °C, with the use of 20 g/L of chloride. A higher temperature (45 °C) and a higher chloride concentration (40 g/L) negatively affected the extraction. The pretreatment stage had favorable effects, in terms of accelerating copper dissolution and improving leaching of copper sulfide ore in acid-nitrate-chloride media. Waste salts from caliche industry and waste brine from reverse osmosis can be used for providing the nitrate and chloride media.