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dissolution-kinetics
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Leaching kinetics of stibnite in sodium hydroxide solution
, Article International Journal of Engineering, Transactions B: Applications ; Volume 27, Issue 2 , February , 2014 , Pages 325-332 ; SSN: 10252495 ; Halali, M ; Hakim, M ; Bakhshandeh, M. R ; Sharif University of Technology
Abstract
The leaching kinetics of stibnite in basic solution has been investigated. Spherical pellets of antimony sulphide were dissolved in 1 molar sodium hydroxide solutions at different temperatures. It was found that the shrinking core with ash layer model could satisfactorily explain the dissolution process. Using this model, it was found that initially the rate controlling step was a chemical reaction with activation energy of 10.2 kJ/mol. As the ash layer built up, diffusion through the ash layer became the rate controlling step. The activation energy for this step was found to be 33.4 kJ/mol. It was also observed that smaller particle size, larger solid to liquid ratio, and higher NaOH...
Optimization of Pressure Leaching of Chalcopyrite Concentrate with Oxygen and Kinetics Study of the Process in Sulfuric Acid Solution
, M.Sc. Thesis Sharif University of Technology ; Yoozbashizadeh, Hossein (Supervisor)
Abstract
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...
Detailed Kinetic Study of Acid Leaching of Uranium ore and Derivation of a Scalable Mathematical Model for it
, M.Sc. Thesis Sharif University of Technology ; Otukesh, Mohammad (Supervisor) ; Karimi Sabet, Jadad (Supervisor) ; Ghodsinejad, Davood (Co-Supervisor)
Abstract
The leaching process is the first stage in the process of extracting uranium out of the ore. The leaching, based on the used material is divided into two main methods of acidic and alkali leaching. Each of these two techniques have their own pros and cones. It is notable that due to lower costs, and faster kinetics, the acid leaching is the first option of the mines unless the percentage of carbonates (and the other acid-soluble materials) in the ore are too high that makes this process uneconomical because of higher acid consumption. The kinetics of the acid leaching of the uranium depends on various parameters such as acid concentration, the particle size, exposure time and the temperature...