| During the roasting oxidation process, the iron phase appears to melt or recrystallize, causing secondary encapsulation of gold, making it difficult for some gold in the calcined to be leached, resulting in higher gold grade in roasting cyanide tailings. Destroying iron oxide in the tailings can increase the leaching percentage of gold. The main gold extraction processes of roasting cyanide tailings were reviewed, including direct acid dissolution, reduction roasting, chlorination, iron making-electrolysis, sulfuric acid ripening method and thiourea method. The direct acid dissolution process is simple, but the gold leaching effect is poor. The reduction roasting method has high gold leaching percentage, but the process is complicated and the energy consumption is high. The chlorination roasting method has strong adaptability to ore and can comprehensively recover valuable metals, but infrastructure and maintenance costs high. The iron-electrolysis method can obtain pure iron products while enriching gold, which has higher requirements on ores. The sulfuric acid ripening method significantly increases the leaching percentage of gold and silver, and requires higher temperature than direct acid dissolution. Thiourea method has a fast reaction rate and good selectivity, but the production cost is high. |
