内蒙古某高砷金矿石碱浸预处理—氰化浸出试验研究

Alkali Leaching Pretreatment-Cyanide Leaching Experiments on a High Arsenic Gold Ore in Inner Mongolia

内蒙古老硐沟金矿金品位波动较大,综合金品位8.27 g/t,可伴随回收银,砷含量高达3.18%。矿石中金嵌布粒度细微,主要以包裹体形态存在于其它矿物中,共生关系密切,且泥化严重。现场采用堆浸法生产,金浸出率仅50%左右,资源浪费严重。为提高金浸出率,在分析矿石性质的基础上,提出采用常温碱浸预处理—全泥氰化浸出工艺,条件试验确定的最佳浸出条件为:磨矿细度-0.074 mm 93.5%,矿浆固液比为1∶2,调节p H=12,碱浸Na OH用量3 000 g/t,预处理2.5 h,浸出剂Na CN用量为2 000 g/t,浸出24 h,最终金、银浸出率分别为85.49%、80.12%。相比堆浸工艺,金浸出率提高了35个百分点以上,并综合回收了银,经济效益显著,可作为该金矿石新的浸出提取工艺。

Gold grade of Inner Mongolia Laodonggou Gold Mine is 8.27 g/t,associated silver can be recovered,arsenic content is as high as 3.1 8%.Gold is finely disseminated and mainly exists in other minerals in inclusions form and closely symbiotic,and easily sliming.Heap leaching method was used on the on-site process while the gold leaching rate is only 50%,resource was seriously wasted.To increase the gold leaching rate,on the basis of the analysis of ore properties,alkali leaching pretreatment-all slime cyanidation leaching process at room temperature was put forward.The optimum leaching conditions de-termined are as follows:the grinding fineness of 93.5% -0.074 mm,pulp solid-liquid ratio is 1 ∶2,ad-justing the pH =1 2,alkali leaching NaOH dosage of 3 000 g/t,pretreatment for 2.5 h,leaching agent NaCN dosage of 2 000 g/t,leaching for 24 h,eventually gold and silver leaching rate were 85.49% and 80.1 2%,respectively.By heap leaching process,the gold leaching rate increased by 35 percentage points,and silver was comprehensive recovered,and the economic benefit is remarkable,can be used as the gold ore new extraction process.