低品位含金硫酸渣氯化焙烧-浸出工艺研究

采用氯化焙烧-浸出工艺处理含金硫酸渣，回收其中金，探究了硫酸渣直接浸出的适宜工艺参数，以及氯化焙烧过程中氯化钠用量、焙烧温度和时间对金浸出效果的影响。结果表明，浸金剂用量 1.5 kg/t、室温下浸出120 min、浸出pH值11.0、液固比2.5∶1的优化浸出条件下金浸出率为66.53%。采用氯化焙烧预处理-浸出工艺处理硫酸渣，在氯化钠用量6%、焙烧温度1 000 ℃、焙烧时间1 h条件下所得焙烧渣在优化浸出条件下浸出，金浸出率可达78.59%，较直接浸出时金浸出率提高了12.06个百分点。通过FESEM-EDS分析发现，氯化焙烧可以改变硫酸渣矿物颗粒表面形貌，使矿物结构变得疏松多孔，释放包裹金，促进浸金剂与金的接触，提高金浸出率。

Gold Recovery from Low-Grade Gold-Bearing Pyrite Cinder by Chlorination Roasting and Leaching Process

A processing technique consisting of chlorination roasting and leaching was adopted to treat gold-bearing pyrite cinder for gold recovery. The appropriate process parameters for direct leaching of pyrite cinder, as well as the influence of sodium chloride dosage, temperature and time of roasting on the leaching behavior were all investigated. The results showed that the gold leaching rate was 66.53% under the following optimum leaching conditions, including the gold leaching agent at a concentration of 1.5 kg/t, leaching at room temperature for 120 min, with pH of 11.0 and liquid-to-solid ratio of 2.5∶1. However, in the test on the pyrite cinder treated by adopting the combined process of chlorination roasting and leaching, after 1 h chlorination roasting at 1 000 ℃ with the sodium chloride at a dosage of 6%, the obtained roasted product was subjected to a leaching process under optimal processing conditions, leading to the gold leaching rate up to 78.59%, showing 12.06 percentage points higher than the leaching rate by direct leaching process. In the following FESEM-EDS analysis, it is also found that chlorination roasting can change the surface morphology of mineral particles in pyrite cinder, leading to minerals with loose and porous structure, thus the enclosed gold is released. As a result, the contact between gold leaching agent and gold is increased, leading to an improvement of the leaching efficiency.