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Cheraghi, Alireza | 2012

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42900 (07)
  4. University: Sharif University of Technology
  5. Department: Materials science and Engineering
  6. Advisor(s): Yoozbashizadeh, Hossein
  7. Abstract:
  8. 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, temperature has a definitely positive effect on the leaching. After temperature, main effects of time and CuCl2 concentration are in the next ranks of importance respectively. The interaction of HCl–temperature is negative and the interactions of temperature –time, time–CuCl2 and temperature –HCl are positive. Based on the results of the screening experiments, optimization tests were designed by applying Response Surface Methodology (RSM) and Central Composite Design (CCD). In the optimal point, 79.76% copper extraction was achieved in the following conditions: T=90°C, t=4.36 hr,[CuCl2] =0.25M (2.5 times of stoichiometric quantity of oxidant as required). According to Pourbaix diagram CuCl32- is the predominant species at optimal condition.The batch leach kinetics appears to fit a shrinking particle model. The leaching rate was controlled by a surface chemical reaction with apparent activation energy of 52.06 KJ/mol and a reaction order of 0.617. The kinetics equation of the process was established as
  9. Keywords:
  10. Kinetics Study ; Chloride Leaching ; 2-Factorial ; Copper Chloride ; Chalcopyrite ; Pourbaix Diagram

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