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含铜0.4%(黄铜矿)的易汞齐金矿石用氰化物进行处理。预浸出时,易溶硫化物的氧化动力学不是处理时间的精确指示。仅在使用氧、硝酸铅和高浓度自由氰化物的特定条件下才能达到有效的金浸出。添加硝酸铅获得了较高的金萃取率,不过在萃取率不降低的条件下氰化物消耗不低于1.85kg/t。如果没有硝酸铅,金回收率低于90%,但采用它则达到98%。氧的添加可增加1.5%的金回收率。硝酸铅用量高于300g/t时,金的萃取对用量的增加不敏感。氧化还原电势值可在不同的氰化阶段作为硝酸铅添加的控制参数。硝酸铅浓度的提高阻止了黄铜矿溶解,但它在降低氰化物消耗上效率不高。溶液中的高铜浓度需要NaCN浓度在700mg/L范围内。当浓度低于640mg/L,金回收率急剧下降。也发现在氰化开始时可直接添加硝酸铅,以达到在预浸出时添加硝酸铅时达到的状态。
The amalgamated gold ore containing 0.4% copper (chalcopyrite) is treated with cyanide. When pre-leaching, the kinetics of the oxidation of the readily soluble sulphides are not an accurate indicator of the treatment time. Effective gold leaching can be achieved only under specific conditions using oxygen, lead nitrate and high concentrations of free cyanide. Addition of lead nitrate gave a higher gold extraction rate, but the cyanide consumption was not less than 1.85 kg / t without lowering the extraction rate. With no lead nitrate, the gold recovery is less than 90%, but with it it reaches 98%. The addition of oxygen increases the gold recovery by 1.5%. When the amount of lead nitrate is higher than 300g / t, the extraction of gold is insensitive to the increase of the dosage. The redox potential value can be used as a control parameter for the addition of lead nitrate at different cyanation stages. The increase in lead nitrate concentration prevents chalcopyrite dissolution, but it is inefficient in reducing cyanide consumption. The high copper concentration in solution requires a NaCN concentration in the range of 700 mg / L. When the concentration is lower than 640mg / L, the gold recovery rate drops sharply. It has also been found that lead nitrate can be added directly at the beginning of cyanidation to reach the state reached when lead nitrate was added during pre-leaching.