Soner Kuşlu

PRECIPITATION CONDITIONS OF CHEVREUL'S SALT FROM SYNTHETIC AQUEOUS CuSO4 SOLUTIONS

In this study, synthetic aqueous CuSO4 solution was prepared at various concentrations. Chevreuls salt was precipitated by passing SO2 through these solutions. Chevreuls salt, a mixed valence copper sulfite, Cu2SO3·CuSO3·2H2O, was characterized by XRD and SEM. The effects of parameters such as initial solution concentration, SO2 feeding rate, reaction time, and initial solution pH on precipitation of Chevreuls salt were investigated. 2n factorial experimental design and orthogonal central composite design methods in the precipitation experiments were used. It was observed that the effective parameters on the precipitation of Chevreuls salt were initial solution concentration, SO2 feeding rate, and initial solution pH. The optimum conditions obtained for maximum copper precipitation were: initial solution concentration 1.14 M, SO2 feeding rate 329.35 L.h.−1, reaction time 25 min, and initial solution pH 8.5. Constant parameters chosen at the initial stage of the reaction were: temperature 62°C, stirring speed 600 rpm, and reaction pH 3 (Çalban et al., 2006). Under these optimum conditions, the percentage of precipitated copper from synthetic aqueous CuSO4 solutions was 99.95.

Optimization of the Dissolution of Tincal Ore in Phosphoric Acid Solutions at High Temperatures

The aim of the study was to investigate the optimization of the dissolution of tincal ore in phosphoric acid solutions at high temperatures in a batch reactor. The effect of the following parameters on the dissolution process was investigated: the reaction temperature, the phosphoric acid concentration, the particle size, and the solid-to-liquid ratio. The best conditions for the dissolution were determined using the 24 factorial experimental design method. The optimum values of the parameters were experimentally determined. The effective parameters were the reaction temperature, the phosphoric acid concentration, the particle size, and the solid-to-liquid ratio. The optimum conditions resulted in the maximum boron dissolution at an acid concentration of 1 M, reaction temperature of 85°C, particle size of 4.75 mesh, and solid-to-liquid ratio of 1/6 g · mL−1. Under these optimum conditions, the best dissolution yield was 98.26%.

EVALUATION OF LEACHING CONDITIONS FOR DISSOLUTION OF PYRITE IN CHLORINE-SATURATED WATER

The optimum leaching conditions for the dissolution of pyrite in water saturated with chlorine gas were investigated. Reaction temperature, solid-to-liquid ratio, reaction time, and particle size were selected as the leaching parameters. 2n factorial experimental design and orthogonal central-composite design methods were used. A mechanical stirring speed of 500 rpm and chlorine gas-flow rate of 1379 mL/minute were chosen as the fixed parameters in all experiments. The degrees of effectiveness from high to low were found to be, in respective order, the particle size, the reaction temperature, the solid-to-liquid ratio, and leaching time. A reaction temperature of 30°C, solid-to-liquid ratio of 0.167 g/mL, particle size of 150–212 μm, and reaction time of 360 minutes were found to be the optimum leaching conditions. The dissolution yield of iron from pyrite was 98.4% under optimal leaching conditions.