Efficient Recovery of the Combined Copper Resources from Copper Oxide Bearing Limonite Ore by Magnetic Separation and Leaching Technology

Abstract

The reserve of the copper-oxide-bearing limonite ore (COBL ore) in Yulong Copper Co., Ltd. is up to 20 million tons with 1.79% of copper content. The characters of the copper resources in the COBL ore are high-proportioned oxidation state (99.98%) and combined state (84.83%). The combined copper oxide is mainly copper-oxide-bearing limonite, which has a copper content of more than 78%. Because of the high altitude and average annual temperature of 15 °C in Tibet, fire leaching cannot be adopted. The leaching efficiency of copper from COBL ore using direct leaching of sulfuric acid is only 40%, which is greatly influenced by temperature and time. Based on the characteristics of COBL ore, a novel combined method of magnetic separation and individual leaching has been proposed to efficient recover copper resources. Experimental results show that the magnetic concentrates and tailings were obtained by magnetic separation of COBL ore at 0.6 T with the yields were 59.65% and 40.35%, respectively. Due to the obvious leaching properties difference of the magnetic concentrates and tailings, individual leaching process routes were used to treat them. The magnetic concentrate was leached with stirring for 3 days at room temperature (20 °C), and the magnetic tailing was easily leached for 4 h at 40 °C. The recovery efficiency of total copper was 72%, which was about 32% higher than that of the single leaching of the COBL ore. The method proposed in this study achieves environmentally friendly, low energy consumption, and efficient extraction of refractory copper oxide ore.

Recovery of copper from deposit of Kola Tembein, Tigray, Ethiopia

“…In recent years, the production of copper from its sulfide ores has decreased, and the best way to meet the need is to produce copper from its oxide. Hence, wise use of refractory copper-oxide resources can improve resource utilization and have a positive impact on the economy [5] .…”

“…Malachite is very soluble and extensively hydrated in sulfurization processes of dissolving in the enrichment of production of copper metal [8] . Although it is challenging to efficiently recover copper resources from these ores to meet demand, the copper leaching efficiency and recovery efficiency are about 40% and 13%, respectively [5] . Thus, it is critical to create a novel, practical, and effective way for fully recovering and utilizing copper from its ore resources.…”

“…Combining beneficiations and leaching is a proven approach for eliminating contaminants from mineral concentrates. It is also a straightforward, economical, and ecologically responsible way to distinguish between magnetic and non-magnetic minerals [5,[9][10][11] .…”

“…Sulfuric acid is frequently used to dissolve copper because of its high leaching effectiveness, minimal environmental impact, and low energy requirements, comparison [14] . Malachite is readily soluble in weak acids, but relatively little research has been done in the dissolution process and how temperature, particle size, and acid and chloride concentrations affect the rate of dissolution [5] . Due to its low boiling temperatures and decompositions, sulfuric acid is typically selected alternative leaching agents for oxidized copper ore [5,6] .…”

“…Malachite is readily soluble in weak acids, but relatively little research has been done in the dissolution process and how temperature, particle size, and acid and chloride concentrations affect the rate of dissolution [5] . Due to its low boiling temperatures and decompositions, sulfuric acid is typically selected alternative leaching agents for oxidized copper ore [5,6] . The gangue mineral calcite, dolomite, and Fe 2 O 3 that is commonly present in malachite ores can metabolize H 2 SO 4 during the acid leaching process [8,9] .…”