The present study reports development of a process to extract copper from malachite ore available at Congo region. The ore was subjected to X-Ray Diffractograms (XRD) and Scanning Electron Microscope (SEM) tests along with the chemical analysis. The major phases found were malachite and chalcocite. The major gangue was quartz. The total copper content was estimated to be 19% and a relative (not fully quantitative) estimation of malachite and chalcocite were found to be 16.31% and 2.68% respectively. Leaching of malachite using 0.6 molar sulphuric acid was completed for both 10% and 20% of pulp density and 5 min was sufficient to extract all the copper values into the solution. Most of the chalcocite and gangue stayed back in the residue. The recovery of copper was close to 75%.

Many entrepreneurs have come forward for process know-how to recover metal values from malachite ore available in Congo region. It is easy to extract copper from Malachite (CuCO3Cu (OH)2) ore if it is not very much contaminated with other difficult forms of copper formation and other impurities. A hydrometallurgical process uses the soluble nature of the oxide ore minerals to the advantage of the metallurgical treatment plant (Atwood and Curtis, 1974). Such oxide ores are usually leached by sulfuric acid, sometimes using a heap leach or dump leach process to liberate the copper minerals into a solution as copper sulfate. The copper sulfate solution (the pregnant leach solution) is then stripped of copper via., a Solvent Extraction and Electrowinning (SX-EW) plant, with the barred sulfuric acid recycled back on to the heaps (Valenzuela et al., 1995; and Bartos, 2002).

Malachite is one of the major oxide ores of copper and hence several investigations were reported previously on leaching of oxidized Cu ores/malachite ores using NH3 media and H2SO4 media (Oudenne and Olson, 1983; Künkül et al., 1994; Yarta and Çopur, 1996; Emin et al., 2004; Bingol and Canbazolu, 2005; and Ursula and Sonia, 2005). Use of aqueous ammonia as the leaching agent is advantageous for its selectivity towards copper and gangue minerals are not attacked. This leads to reduction in reagent consumption, but at the same time overall kinetics is slow.

The leaching of oxide copper ore containing malachite, which is the unique copper mineral in the ore, by aqueous ammonia solution has been studied by Bingol and Canbazolu (2005). The effect of leaching time in ammonium hydroxide and ammonium carbonate concentration, pH, (NH3)/(NH4+) ratio, stirring speed, solid/liquid ratio, particle size, and temperature were investigated.

Chemical Engineering Journal, Metal Ions Onto Eggshell Powder, Heavy Metal Contamination, Water Resources, Traditional Treatment Techniques, Aquatic System, Equilibrium Biosorption Data, Biosorption Processes, Biomass Concentration, Biosorption Equilibrium, Biosorption Isotherm, Redlich Peterson Models.