INVESTIGATION OF LEACHING KINETICS AND MECHANISM OF PANDERMITE MINERAL IN SULPHURIC ACID SOLUTIONS
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Publication date: 2015-06-16
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Aycan Gur
Science, Yuzuncu yil university, 65080 Van, Turkey
Physicochem. Probl. Miner. Process. 2015;51(2):719-730
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Abstract: The leaching kinetics and mechanism of pandermite mineral having the formula of 4CaO.5B2O3.7H2O was investigated in sulphuric acid solutions. For the dissolution process the effects of reaction temperature, sulphuric acid solution concentration, solid/liquid ratio, particle size and stirring speed were used as effective parameters in the experiments. The experimental data indicated that the dissolution rate increased with increasing reaction temperature, decreasing particle size and solid/liquid ratio. The conversion rate increased up to 1,0 mol.L–1 with increasing acid concentration and then decreased with increasing acid concentration over concentrations of 1 mol.L–1. It was also determined that stirring speed was no significant effect on the dissolution rate. The dissolution process of pandermite in sulphuric acid solution was tested with regard to heterogeneous and homogeneous reaction models and it was found that the dissolution rate was controlled by first order pseudo-homogeneous reaction model. The activation energy of the dissolution process was determined as 26, 07 kJ.mol-1. The results were assayed graphically and statistically, then it was detected that the following mathematical model was good fitted to the experimental data, ln(1-X)=1.04x102(D)-0.8822(C)0.7090 (S/L)-0.3436 exp(-3130/T)t.