Promoted Solvent Extraction of Gold from Cyanide Solution with Aliquat336/DEC/MIBK Synergistic System

Abstract

This study investigated various combinations of extractants for extracting gold from cyanide solutions. Methyl isobutyl ketone (MIBK), diethyl carbonate (DEC), and tributyl phosphate (TBP), when used alone, showed limited efficiency, with a maximum extraction of 34% for MIBK. In contrast, methyl trialkyl ammonium chloride (Aliquat 336) exhibited high extraction rates across different organic to aqueous ratios (O:A) alone. Synergistic effects of MIBK, DEC, and TBP with Aliquat 336 were also evaluated, achieving 90.6% gold extraction at a 1:1 O:A ratio with reduced consumption of Aliquat 336. The McCabe-Thiele curve was plotted for the optimal combination, Alq336/MIBK/kerosene, revealing that three extraction stages were required at a 1:2 O:A ratio for optimal results. A batch counter-current simulation was designed, showing that the three-stage extraction process at a 1:3 O:A ratio increased gold recovery from 87.2% (using Aliquat 336 alone) to 93.3% with the Alq336/MIBK mixture. Stripping of the loaded organic phase was conducted with a 4 M sodium thiosulfate solution, achieving an efficient 98% stripping of gold from the organic solvent. This comprehensive study demonstrates the potential of synergistic extractant combinations and multi-stage extraction processes for enhanced gold recovery, providing a viable alternative to traditional methods.