DETERMINATION OF THE OPTIMUM CONDITIONS FOR THE DISSOLUTION OF STIBNITE IN HCL SOLUTIONS

The Taguchi method has been used to determine optimum conditions for t he dissolution of stibnite in HCl solutions. Chosen experimental param eters and their ranges were (i) reaction temperature, 25-70 degrees C; (ii) solid-to-liquid ratio (in weight), 0.1-0.25; (iii) acid concentr ation (in weight), 23.71-37%; (vi) mean particle size; 0.1061-0.8426 m m; (v) stirring speed, 200-800 rpm; (vi) reaction time, 5-60 min. The optimum conditions were found to be reaction temperature, 70 degrees C ; solid-to-liquid ratio, 0.125; acid concentration, 37%; mean particle size, 0.1061 mm; stirling speed, 700 rpm; reaction time, 60 min. Unde r these optimum conditions the dissolution of stibnite was approximate ly 99%. Next, for the experimental conditions of a time value 15 min l ess than its optimum value, a value of solid-to-liquid ratio twice its optimum value, and the remaining parameters at their optimum values, it was found that a benefit of 0.023 $/g SbCl3 could be gained from th e cost of acid and electricity against a loss of 7.5 x 10(-4) $/g SbCl 3 as a result of the 1.5% decrease in the Sb recovery due to the chang es in optimum conditions.