Extractive extraction for platinum recovery using synergistic organic formulation of Aliquat 336/TBP mixtures

Abstract

The source of platinum in the earth’s crust has become diminishing nowadays, thus recycling platinum from a secondary source is highly demanded. Hydrometallurgical processes have been used as an alternative method instead of pyrometallurgical. In this process, extractive solvent extraction is the core of operations. This study aims to find the synergistic formulation for platinum extraction as well as to study the extraction and stripping mechanism of the separation process. The extraction was performed by using a synergist organic formulation of basic and solvating where Aliquat 336 and tributyl phosphate (TBP) were used as a base and synergist extractant, respectively. Palm cooking oil was used as a green diluent. At 5x10-5 M TBP + 5x10-4 M Aliquat 336, 85% of platinum was extracted and the synergistic coefficient (SC) in this work was 1.29. Aliquat 336 acts as a synergist while TBP acts as a base. Based on the mechanism, it was concluded that one mole of Aliquat 336 and one mole of TBP can extract one mole of platinum ion. Then, the stripping process of the loaded extractant/platinum was done using the mixture of HCl and thiourea. At the optimum concentration of the stripping agent (0.5 M HCl + 0.5 M thiourea), 93% platinum was stripped which was considered a high stripping efficiency. Therefore, the synergistic formulation of the extractive extraction process offers great potential for platinum recovery from the aqueous solution.