微细浸染型金矿硫脲—硫氰酸铵浸出研究

Leaching of Au from Micro-disseminated Gold Ore in Thiourea-Thiocyanate Solutions

某微细浸染型金矿化学分析结果显示,金品位为3.51×10-6,Si O2含量较高(占71.88%),有机碳质量分数高达2.51%,XRD和金物相分析可知,矿石中主要矿物为石英、方解石及硫化矿,金矿石主要以微细粒浸染型为主,或包裹于石英、硅酸盐、硫化矿及碳酸盐矿物中。采用焙烧—硫脲或硫氰酸铵单体系浸出时,金浸出率较低;采用焙烧—硫脲、硫氰酸铵混合体系浸出时,可获得较好的浸出率。通过析因试验研究硫氰酸铵、硫脲(Tu)和硫酸铁对金浸出的影响,结果表明硫酸铁和硫氰酸铵相互作用显著。通过优化浸出时间、p H值和液固比,得到混合体系浸金的较优条件。结果表明:在焙烧温度为600℃、焙烧时间为60 min、p H=1.06、硫酸铁用量为14 kg/t、硫氰酸铵用量为10 kg/t、硫脲用量为2 kg/t、浸出时间为7 h和液固比为3∶1的条件下,可获得75.03%的金浸出率。

The analysis results of ore chemical composition at a certain micro-disseminated gold demonstrated that gold grade was 3.51×10-6,content of SiO2 was as high as 71.88%.In addition,the content of organic of carbon even reached up to 2.51%.After analyzing the XRD and phase of gold,it was found that the ore main minerals were primary composed with quartz,calcite and sulfide.According to the characters of the ore,when employing the thiourea or thiocyanate leaching directly,low leaching rate can be obtained.When employing the thiourea-thiocyanate leaching,better leaching rate can be obtained.Using factorial experimental,paid attention to the amount of thiocyanate,thiourea and ferric sulfate.The results showed that the amount of ferric sulfate and thiocyanate dosage interaction significantly.Then optimize the leaching time,pH,liquid-solid ratio.The test results showed that under the conditions that roasting temperature is 600 ℃ and roasting time is 60 min,the gold leading rate of 75.03% was achieved when pH is 1.06,the dosage of ferric sulfate,thiocyanate and thiourea are 14 kg/t, 10 kg/t and 2 kg/t respectively,the leading time is 7 h,liquid-solid ratio is 3∶1.