Sharif Digital Repository

In recent decades, various studies have performed on leaching of sulphide ores in ammoniacal thiosulphate solution for the recovery of precious metals such as gold and silver and significant results have been gained. In this study, the ammonia thiosulfate solution utilized to dissolve copper sulfide concentrate, which contained chalcopyrite. The effect of various parameters such as grain size, thiosulfate and ammonia concentration, solid to liquid ratio, temperature and pH in turbulent leaching process were considered to obtain the optimum conditions in the laboratory scale. The outcomes obtained by chemical analysis were evaluated. The results demonstrate that maximum dissolution (26.72%)... 

High advantages of hydrometallurgy have led to its recent development in metal extraction. Many investigations are being carried out on applying hydrometallurgy processes on copper extraction. In this study, the chloride leaching of chalcopyrite in a concentrated sodium chloride solution (4M) –which is a novel process–, using CuCl2 as leachant is investigated. Main effects and interactions of temperature (50–90°C), time (2–6 hr), CuCl2 concentration (0.1–0.5M), pulp density and HCl concentration (0.1–1M) at constant stirring rate (600 rpm) on leaching is studied using 2k factorial design and applying Design–Expert 7.0.0 software. While the effect of pulp density is almost negligible,... 

Nowadays, because of drastically decrease of copper sulfide ore’s grade, and difficulties in leaching of them, new processes of copper production like bioleaching technique become significant. Finding the optimal conditions for bioleaching, require investing a lot of time and cost. Computer simulation is useful in this case. Temperature, affects the kinetics of dissolution reactions, type and growth rate of bacteria, and finally, rate and amount of recovery of valuable copper metal from ores, so determination of temperature within the bioheap is very important. Thermophiles are better than mesophiles in chalcopyrite bioleaching and in the range of 55 to 65 degree centigrade, thermophiles... 

The enormous benefits of hydrometallurgical processes have led to the progressive metals extraction industry. Many studies are carried out on the application of these processes in the copper extraction industry. In this research, the oxygen pressure leaching of chalcopyrite concentrate was studied. Experiments were carried out under conditions of the solid-liquid ratio of 0.1, agitation speed of 750 rpm, and sulfuric acid concentration of 2M in a stainless-steel autoclave system. Central composite design (CCD) was used to design experiments, and three factors of temperature, time, and pressure of oxygen, were selected as design variables. The obtained model for %Cu includes parameters of... 

High advantages of hydrometallurgy have led to its recent development in metal extraction. Many investigations have been carried out on applying hydrometallurgy processes on copper extraction. In this study, Chalcopyrite concentrate produced in Sarcheshmeh copper plant was subjected to oxidative leaching investigation by cupric ion to determine the effect of several parameters on the copper and iron dissolution, included temperature of leaching, time of holding and cupric concentration as oxidant agent in a range of 38-97°C, 1.5-8.5 hours and 0.2-0.8 M respectively. The leaching media was chloride providing with 3M HCl 37% and CuCl2. The experiments were designed by central composite...