陇南紫金难处理金精矿工艺矿物学研究

采用多元素分析、X射线衍射、矿物解离度分析和电镜扫描等方法，开展陇南紫金金精矿的工艺矿物学研究，深入分析矿物组分、各物相赋存状态以及金的伴生规律。研究结果表明：该金精矿S和As质量分数分别为42.12%和2.31%，硫化物包裹金占比为56.19%，属于硫化物包裹难处理金矿；金矿物粒度为1~10 μm，以银金矿为主，并含有少量的自然金；金矿物的单体解离度为30%，未解离的金矿物均与黄铁矿连生，呈半包裹半裸露状或完全被包裹状。基于金矿物的单体解离度随着矿物粒度减小而增大的特性，可通过超细磨的方法，增加金与浸金试剂的接触，为提高金的回收率创造良好条件。

Study on Technological Mineralogy of Gold Concentrate in Longnan Zijin

Refractory gold ore is a kind of gold ore which can not be effectively extracted by conventional cyanidation process after fine grinding.High-sulfur ore is the most common refractory gold deposit in China.Refractory gold concentrate is an enrichment of gold grades greater than 10×10^-6 obtained by fine grinding re-election or flotation of refractory gold ore.In view of the complex mineral composition of refractory gold concentrate with high sulphur content and the characteristics that gold is often encapsulated in other minerals，the process mineralogy of a gold concentrate in Longnan Zijin was studied by means of multielement analysis，X-ray diffraction，mineral dissociation analysis and scanning electron microscopy.The mineral composition，the occurrence state of various phases and the associated law of gold were thoroughly analyzed，to provide theoretical basis for the selection of gold extraction process for gold concentrates.The results show that the S and As contents of the gold concentrate are 42.12% and 2.31% respectively，and the proportion of gold encapsulated by sulfide is 56.19%.The gold concentrate belongs to the refractory gold deposit encapsulated by sulfide.The main gangue in the gold concentrate are quartz and sericite.The main metal minerals in the gold concentrate are natural gold，silver-gold ore，pyrite and arsenopyrite，of which pyrite accounts for 79.6% and is the main carrier of gold minerals.The content of pyrite and arsenopyrite increased from 63.83% and 1.77% to 82.95% and 4.85% respectively，while the content of quartz and sericite decreased from 23.57% and 8.37% to 5.91% and 4.97%，respectively，when the particle size of the gold concentrate decreased from +0.075 mm to -0.045 mm.The size of gold minerals ranges from 1 to 10 microns，the Au content in gold minerals is 74% to 89%，the Ag content is 9% to 23%，and the Fe content is 1% to 9%.The main gold minerals are silver and gold deposits，accounting for 86.67%.In addition，there are a small amount of natural gold，accounting for 13.33%.The liberation degree of gold minerals is 30%.The encapsulated gold minerals are associated with pyrite，which is semi-encapsulated or completely encapsulated，and the encapsulated gold often occurs in the pores of pyrite grains.The degree of monomer dissociation of gold minerals increases with the decrease of sample size.That is，the regrinding of concentrate is beneficial to the exposure of gold particles，making gold particles fully contact the leaching solution，thus improving the leaching rate of gold.