载金硫化物焙烧--自浸出过程研究

针对传统氧化焙烧-氰化浸金工艺环境污染严重的现状，采用焙烧-自浸出工艺提取载金硫化物中的金.研究焙烧温度、焙烧时间和试样量对单质硫转化率和金浸出率的影响，通过X射线衍射分析、扫描电镜观察、能谱分析等手段分析焙烧过程中载金硫化物中硫的物相转变规律.载金硫化物中黄铁矿发生热分解反应生成单质硫和磁黄铁矿，随焙烧温度的升高和焙烧时间的延长，黄铁矿的特征衍射峰强度逐渐减小直到消失，磁黄铁矿的特征衍射峰逐渐生成并增强，原本致密状的黄铁矿颗粒变得疏松多孔.50 g试样在氮气流量1 L·min-1、焙烧温度800℃、焙烧时间60 min的条件下，单质硫的转化率达到42.53%，金浸出率达到88.70%，实现载金硫化物的高效非氰浸出.

Roasting and self-leaching process research of gold-bearing sulfides

In view of serious environmental pollution in the traditional roasting-cyanide leaching process, a roasting and self-leaching process was adopted to treat gold-bearing sulfides. The transformation rate of elemental sulfur and the gold leaching rate were tested at different roasting temperatures, roasting times and sample masses. The phase transformation of sulfur in the sulfides was ana-lyzed by X-ray diffraction analysis, scanning electron microscopy and energy dispersive spectrometry. It is found that pyrite in the sul-fides transforms to elemental sulfur and pyrrhotite because of a thermal decomposition reaction. Along with the increasing of roasting temperature and roasting time, the characteristic diffraction peaks of pyrite gradually weaken and finally disappear. Meanwhile, the characteristic diffraction peaks of pyrrhotite generate and heighten. The initial dense pyrite particles become porous. Under the condi-tions of the roasting temperature of 800℃, roasting time of 60 min, nitrogen flow of 1 L·min-1 and sample mass of 50 g, the transfor-mation rate of elemental sulfur and the gold leaching rate reach 42. 53% and 88. 7%, respectively. Gold from the sulfides is effective-ly extracted by this non-cyanide leaching.