Abstract: The ore properties of a refractory arsenic-containing gold ore in Qinghai is complex， and the grade and recovery rate of the produced gold concentrate are low. In order to fully grasp the ore properties and improve the gold grade and recovery rate， the process mineralogy of the ore was studied systematically by means of polarizing microscope and field emission scanning electron microscope （SEM）. The results showed that: ①The distribution of gold grade in different mining areas is extremely uneven， and the average gold grade is 3.0 g/t. The main metallic minerals in the ore are pyrite， a small amount of sphalerite and galena，trace chalcopyrite and a small amount of arsenopyrite. The main non-metallic minerals are quartz and feldspar， as well as part of epidote， diopside， sericite and calcite. ② The main non-metallic minerals in the ore are the electrum of 81.58%， the rest are the natural gold of 14.80% and the kustelite of 3.62%. The gold mineral particles in the ore are fine with the maximum particle size of 31 μm and the minimum particle size of 2 μm，in which the average particle size is of 10 μm. The contents of the fine and minuteness gold are accounting for 93.39% and 6.64%， respectively. The occurrence of gold minerals can be divided into the three types of encapsulated gold， interstitial gold and fissure gold with 79.30% of encapsulated gold， 12.76% of interstitial gold and 7.94% of fissure gold. The morphology of gold minerals is mainly round granular， and the rest are long strip and irregular. ③The main gold-bearing minerals in the ore are pyrite and a small amount of arsenopyrite. Compared with the iron contents in ideal pyrite， the iron contents in common pyrite and gold-bearing pyrite in the ore is 2.06 percentage point and 2.66 percentage point lower， respectively， showing the characteristics of low iron and high sulfur. The contents of iron and arsenic in common arsenopyrite and gold-bearing arsenopyrite were lower than ideal ones， and the contents of iron and arsenic in common arsenopyrite were 1.65 percentage point and 3.30 percentage point lower， respectively. The contents of iron and arsenic in gold-bearing arsenopyrite are 0.50 percentage point and 6.15 percentage point lower， respectively. The contents of sulfur in common arsenopyrite and gold-bearing arsenopyrite are 4.28 percentage point and 6.65 percentage point higher than that in ideal arsenopyrite， respectively. ④ The main gold-bearing mineral in the ore is pyrite and the gold particle size is micro-fine. It is suggested to improve the monomer disintegration degree of pyrite and strengthen the collection of pyrite to further increase the recovery rate of the gold.

Key words: arsenic-containing gold ore, dissemination charateriastic, granularity analysis, occurrence state and morphology of gold