选冶联合处理低品位含金尾矿的试验研究

Experimental Research on Treatment of Low-grade Gold-bearing Tailings by Combined Process of Concentration and Smelting

为高效回收尾矿资源中的金矿物,对含金尾矿进行了选冶联合试验研究。化学分析结果表明,固体废弃物中的金含量为0.86 g/t。工艺矿物学研究表明,矿样宜采用浮选—浮选金精矿预处理—浸出的选冶联合工艺来回收金。浮选条件试验、开路试验和闭路试验研究结果表明:粗选在Na2CO3用量为500 g/t、(NaPO3)6(六偏磷酸钠)用量为50 g/t、CuSO4用量为75 g/t、异戊基黄药+丁铵黑药用量为120 g/t、松醇油用量为40 g/t的条件下,通过“一次粗选—两次扫选—两次精选”的闭路工艺流程,可获得产率为14.23%、金品位为5.21 g/t、金回收率为86.21%的金精矿。在金精矿磨至-0.037 mm占70.12%的条件下,直接浸出率为41.60%,金的浸出效果不理想,主要原因是大部分金呈微细粒被黄铁矿包裹以及金矿物多为碲金矿、碲金银矿和含金碲银矿等所致;金精矿氧化焙烧—氰化浸出的合适条件为氧化焙烧温度为750℃、焙烧时间为60 min、焙砂细度为-0.037 mm占85%、矿浆浓度为33%、矿浆pH值为10.5、NaCN用量为10 kg/t、浸出时间为24 h,在此条件下金的氰化浸出率为73.76%,与金精矿直接氰化指标(金氰化浸出率为41.60%)相比,金的氰化浸出率提高了32.16%。

In order to recover gold from solid waste efficiently,a combined beneficiation and metallurgical test was carried out on gold-bearing tailings.The results of chemical analysis show that the gold content in solid waste is 0.86 g/t.Process mineralogy showes that the main gold minerals are tellurite ore,tellurium-gold-silver ore and gold-bearing tellurium-silver ore,followed by natural gold and silver-gold ore.In the original ore sample,gold is mainly produced in the form of sulfide wrapped gold,accounting for 51.72%,followed by bare gold,accounting for 31.03%,a small amount of gold is produced in the form of quartz wrapped gold,accounting for 17.24%.The original ore sample was vibrated to the particle size of-0.074 mm accounted for98.15%.According to chemical phase analysis,gold is still mainly produced in the form of sulfide wrapped gold,accounting for 50.00%,with little change.Part of gold is produced in the form of bare gold,accounting for41.86%,and a small amount is produced in the form of quartz wrapped gold,accounting for 8.14%.It can be seen that grinding can obviously improve the leaching rate of gold.If gold is recovered by flotation,the recovery rate of gold can be increased.At the same time,it can also be seen that the recovery rate of gold is less than 50%by direct cyanidation leaching method,and the gold in the ore sample needs to be recovered by the combined process of concentration and smelting.The flotation gold concentrate pretreatment leaching process for gold concentrate should be adopted to recover gold.The closed circuit process of"one roughing-two sweeping-two cleaning"was adopted.Gold concentrate with the yield of 14.23%,gold grade of 5.21 g/t and gold recovery of86.21%can be obtained.When the gold concentrate is grinded to-0.037 mm accounted for 70.12%,the leaching rate of direct cyanide gold is 41.60%.The main barrier effecting the gold leaching is that most gold is wrapped by pyrite and gold minerals are mainly tellurite,tellurite,gold-bearing silver tellurite,etc.The oxidizing roastingleaching improved the leaching rate effectively.The suitable conditions for the oxidation roasting cyanidation leaching of gold concentrate are:The temperature of oxidation roasting is 750℃,the roasting time is 60 min,and the fineness of the roasting sand is-0.037 mm accounted for 85%,pulp concentration is 33%,pulp pH value is 10.5,sodium cyanide dosage is 10 kg/t,leaching time is 24 h.Under these conditions,the cyanide leaching rate is of gold is 73.76%,compared with the direct cyanide index of gold concentrate(cyanide leaching rate is 41.60%),the cyanide leaching rate of gold is increased by 32.16%.