No abstract

The kinetics of leaching of calcined magnesite by citric acid solution was studied. The effects of reaction temperature, particle size, and acid concentration were investigated. The leaching data showed that the reaction is under chemical kinetics control with an activation energy of 39.1 kJ mol -1 . Additionally, the fact that leaching was controlled by the chemical reaction was also supported by the relationship between the rate constant and the particle radius.

No abstract

A study was performed on the chlorination and cementation of gold from an anode slime. The gold from decopperized anode slime first was dissolved with chlorine gas in aqueous medium, later the dissolved gold was precipitated by using a rotational copper disc. The effects of reaction temperature, reaction period, stirring speed, solid‐liquid ratio and Cl2 gas flow rate on the dissolution of gold were investigated. Increasing the solid‐liquid ratio decreases the dissolution, the solubility increases with increasing reaction temperature, reaction period and stirring speed. It was observed that the Cl2 gas flow rate hasn't a significant effect on the dissolution. As to the precipitation of the gold in the solution, the effects of temperature and rotational speed were sought for. The experimental results showed that the gold recovery could be over 90 %. For the kinetics analysis of the cementation, the activation energy value was found to be 19.51 kJ·mol–1.

No abstract