Recovery Of Copper From The Wasted Copper Oxide Residues

As a kind of secondary copper resources, it makes good sense to recycle the copper residues. On one hand, the recycling could resolve some environmental problems, on the other hand, the situation of copper deficiency in industry could be converted, with realization of comfortable economic benefit. The comprehensive recovering of the wasted copper oxide residues in Guangxi Zhuang Autonomous Region was investigated in this paper, while the technical route to recover copper efficiently was obtained by optimizing the process conditions.The investigation on sample properties indicates that copper grade of the residues is1.75%, with high content of alkaline gangues and low content of sulfur, of which the contents of calcium oxide, quartz and sulfur are23.68%,29.22%and0.098%, while the ratios of oxidized and locked copper minerals are96.23%and77.10%, respectively. In the residues, the copper minerals is mainly composed of chrysocolla, accompanied by malachite, azurite and a little native copper, while the gangues consist of quartz, mica and dolomite.The treating process for the comprehensive recovering of copper is determined as "Sulphidizing flotation-Ammonia leaching-Extraction-Back extraction". Effects of grind fineness, sulphidizing agent-to-sulphidizing accelerator ratio, sulphidizing agent dosage, ore pulp pH and hydroximic acid collectors on the copper residues flotation were researched. The flotation index of close circuit test is achieved according to "two-stage grinding and flotation" flow, with the copper recovery of61.89%, concentrate average grade of10.5%and tailings grade of0.76%. In the ammonia leaching experiments of flotation tailings, effects of lixiviant concentration, solid-to-liquid ratio, stirring speed and reaction temperature on copper extraction ratios at various time were investigated. Under the optimal condition of leaching process, the leaching recovery of70.6%was achieved and the phase analysis for leaching residue was carried out, on basis of which the leaching mechanism of copper oxide minerals was explored. Kinetics analysis indicates that the copper leaching ratio is controlled by diffusion through the product layer in the initial60minutes of leaching, with the activation energy of32.3kJ/mol. The experiments of copper recovering from lixivium with1.77g/L Cu was conducted through the process of extraction and back-extraction, with15%Lix84-I+solvent kerosene being the organic phase of extraction and200g/L H2SO4solution being the aqueous phase of back extraction. After two-stage extraction, one-stage scrubbing and two-stage back extraction, a good result of copper separation by extraction process is obtained, with13.21g/L Cu in the aqueous phase.