Abstract
Cyanide tailings produced in gold smelting process contain a large number of heavy metals and cyanides, which are more and more harmful to the environment. In order to reduce environmental pollution, valuable metals from cyanide tailings are recovered. The amount of calcium chloride, chlorination time, the way of adding calcium chloride and other factors on the influence of gold and silver extraction by chlorination were studied by using the raw material of cyanide tailings with melting chlorination process in this paper, and how to reduce the melting chlorination temperature was explored, and a comprehensive experiment was carried out under the best conditions. The results showed that when the chlorination temperature is 1500°C, the chlorination time is 1 h, and the addition amount of CaCl<sub>2</sub> is 7%, the volatilization rate of gold is 85.38%, the content of gold in slag is 1.83 g/t, the volatilization rate of silver is 77.36%, and the content of silver in slag is 4.12 g/t; when the chlorination temperature is 1500°C, 7% CaCl<sub>2</sub> is added, and the chlorination time is 15 min, the volatilization rate of gold is 87.78%, the content of gold in slag is 1.23 g/t, the volatilization rate of silver is 59.40%, and the content of silver in slag is 7.39 g/t; the addition of 5% CaO can change the slag type, reduce the chlorination temperature by 50~100°C, increase the volatilization rate of gold and silver slightly, and decrease the content of gold and silver in slag; when CaCl<sub>2</sub> is added in five times, the volatilization rate of gold increases to 95.53%, the content of gold in slag decreases to 0.56g/t, the volatilization rate of silver increases to 77.80%, and the content of silver in slag decreases to 4.04 g/t; 7% CaCl<sub>2</sub> was added in five times, and the melting chlorination time was 15 min. the amount of CaO was 5%, and the melting chlorination temperature was 1450°C, the gold volatilization rate is 95.69%, and the gold content of slag is 0.54 g/t, the silver volatilization rate is 77.06% and the silver content of slag is 4.20 g/t.
Highlights
Cyanide tailings are a kind of waste residue of gold cyanidation smelting, which contains a large number of heavy metals [1] and cyanide
BGRIMM has further developed a new generation of chlorination volatilization process for gold extraction based on the existing chlorination roasting process
The volatile rate of gold only increased by 3% when the addition of calcium chloride increased by 5%, and the gold content in tailing only decreased by 0.4 g/t to 1.42 g/t
Summary
Cyanide tailings are a kind of waste residue of gold cyanidation smelting, which contains a large number of heavy metals [1] and cyanide. It is necessary to develop a gold extraction technology which can efficiently recover valuable metals from cyanide tailings, reduce environmental pollution and realize integrated recycling of resources. On the basis of photosynthetic method, BGRIMM Technology Group (hereinafter referred to as "BGRIMM") has developed chlorination roasting volatilization process to recover valuable elements such as gold and silver from cyanide tailings. BGRIMM has further developed a new generation of chlorination volatilization process for gold extraction based on the existing chlorination roasting process It is a process for integrated recycling of gold, silver and other valuable metals from cyanide tailings by short process molten salt chlorination under high temperature. Tailings by Melting Chlorination recovery rate, small amount of flue gas and without secondary hazardous waste tailings It can effectively deal with cyanide tailings and realize gold extraction without cyanide
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