Purification of Zinc from the Bioleaching Solution of a Bulk Lead-Zinc Concentrate by Precipitation and Solvent Extraction

Bioleaching, in combination with the solvent extraction (SX) method, can be implemented to extract metals from mineral resources. The leachate obtained from the continuous bioleaching of a bulk lead-zinc concentrate was subjected to the purification studies. Firstly, 83% of the iron content of the leachate was removed using the jarosite precipitation method. Then, Di-(2-ethylhexyl) phosphoric acid (D2EHPA) extractant was saponified by 25% using NaOH and diluted with kerosene to be applied in the solvent extraction studies. In the third step, SX optimization experiments were conducted to obtain the best values for the mixing time, pH, temperature, extractant percent, and O/A ratio. Finally, the McCabe-Thiele diagram was constructed at the optimized condition [12 min, pH 3.5, 25 degrees C, 30% Di-(2-ethylhexyl) phosphoric acid], and 99.9% zinc recovery was predicted after two extraction stages at the O/A ratio of 1.