Mechanism of synergistic pretreatment with ultrasound and ozone to improve gold and silver leaching percentage

Abstract

Refractory gold ore is becoming the main gold resources at present. The sulfide coating on the surface of gold inhibits the leaching of gold and increases the consumption of reagents. The synergistic pretreatment ofozone and ultrasound is utilized to oxidize the sulfide coatings on the surface of gold and the synergistic mechanism is studied. Theozone and ultrasound pretreatment prominently increased the leaching percentage of gold from 49.12% to 93.52% and the leaching percentage of silver from 4.01% to 61.25% after 4 h. During the pretreatment, ozone effectively oxidized the sulfide enclosure(FeS2). The secondary-enclosure caused by pyrite oxidation is significantly inhibited by ultrasound. Meanwhile, the ultrasound significantly reduces particle size and increases specific surface area of the refractory gold ore, which intensified the oxidation process during the pretreatment. The pretreatment of ultrasound and ozone not only oxidized pyrite enclosure, effectively damaged pyrite enclosure and restrain secondary enclosure within a short time, also evidently increased the gold and silver leaching percentage.