New ways to recover gold

Hiroshima University in Japan has developed a new method for the efficient recovery of gold from gold-containing waste liquids. This method is carried out by utilizing the chemical reaction that the complex selectively adsorbs metal ions and forms a metal complex. The process is: adding a cyclic polyamine compound dissolved in chloroform in a strong acidic gold mixture with a PH value of 1 or less, stirring for half an hour, and fully reacting the gold and the cyclic polyamine compound to generate Gold complexes. The mixed solution of this complex and other metals is divided into two phases in the reaction vessel, the gold complex sinking at the bottom of the reactor. After taking out the gold complex, it is heated to 60°C. In a neutral or slightly alkaline aqueous solution with a pH of 8 and stirred for half an hour, the gold complex is divided into gold and polyamine due to structural instability. Substances. The gold and polyamine solutions are still in the form of two phases, and the gold remains in the upper part of the reactor and is thus easy to recycle. One kilogram of mixed solution containing gold, copper, cobalt, palladium and other metals is used for testing. The extraction rate can reach 90% at a time. Repeated extraction can recover all the gold.