云南大理氧化金堆浸尾矿含金0.75 g/t,具有一定的经济价值,该矿多呈黑褐色,少数呈红褐色、灰色、米黄色,其中黑褐色矿石中磁铁矿、赤铁矿及褐铁矿的含量常大于50％,有的可达80％左右,呈稠密浸染状分布.金主要以自然金的形式存在,部分金产于泥质中,部分半包裹-包裹于褐铁矿及磁(赤)铁矿中,自然金粒度微细,为0.003 ～0.03 mm.因此,该堆浸金尾矿宜用“炭浸法”提金.为了再次提取这部分金,本试验主要对磨矿细度、氰化钠浓度、浸出时间、活性炭密度等条件进行优化,后采用炭浸法(也称为CIL法)工艺提金,获得金浸出率56.08％、银浸出率22.65％,金吸附率90.48％,氰化钠耗量0.72 kg/t的技术经济指标,实现了资源的二次利用.%The grade of gold in the heap-leaching tailings from Dali in Yunnan province is 0.75 g/t,which has certain economical value.The tailings are mainly black-brown,and a few are reddish brown,gray or beige.The content of magnetite,hematite and limonite in the black-brown is more than 50 percent,some even 80 percent.These iron minerals are distributed in dense and disseminated form.Gold in the tailings is mainly native one,some gold in argillaceous and some wrapped in hematite,magnetite and limonite.The particle size of native gold is fine from 0.003 mm to 0.03mm.So the reasonable gold-extraction process is the carbon-in-leach one.To recover this part of gold,the test research on the grinding fineness,concentration of sodium cyanide,leaching time and the density of activated carbon were conducted.Then the proper gold leaching process was achieved,which was carbon-in-leach process,also known as CIL method.The results show that finally the gold leaching rate of 56.08％,silver leaching rate of 22.65％,gold adsorption rate of 90.48％,sodium cyaniding consumption of 0.72 kg/t were achieved through the trial,which realizes the secondary recovery of gold.
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