金精矿中硫化物在微波加热过程中的物相变化

Phase Transition of Sulfide in Gold Concentrate During Microwave Heating

以福建双旗山金精矿中的主要硫化物黄铁矿为研究对象,采用微波加热-磁选的方法,考察了微波加热过程中黄铁矿的物相变化。研究结果表明:黄铁矿微波加热过程中生成的磁性矿物类型受加热温度控制,生成量受加热温度和时间影响;在500℃时黄铁矿开始分解为强磁性的磁黄铁矿;600℃所得产物有黄铁矿与磁黄铁矿共存颗粒,且磁黄铁矿晶体结构不同;700℃所得产物主要为单斜的磁黄铁矿,有黄铁矿与磁黄铁矿共存颗粒存在;800℃下产物为单斜的磁黄铁矿,伴随生成少量的α-赤铁矿。金精矿中的主要硫化物黄铁矿在微波加热过程中的物相变化路径为黄铁矿→磁黄铁矿→磁铁矿→赤铁矿。

Pyrite as the predominant sulfide in the gold concentrate of Fujian Shuangqishan Gold Mine was taken for study and the phase transition of it during microwave heating in the process of microwave heating-magnetic separation was investigated. Results showed types of magnetic products generated in the process of microwave heating of pyrite depend on the heating temperature, while the production being influenced by both heating temperature and heating time. Study also indicated that pyrite began to decompose to be pyrrhotite at 500 ℃; products generated at 600℃ showed coexistence of pyrite and pyrrhotite that has quite different crystal structures; products generated at 700 ℃ were predominantly monoclonal pyrrhotite with the coexistence of pyrite and pyrrhotite; while products generated at 800℃ were monoclonal pyrrhotite accompanied by some trace of a-hematite. It is concluded that pyrite as the predominant sulfide in the gold concentrate follows the following order of phase transition in the process of microwave heating： pyrite →pyrrhotite →magnetite→hematite.