Research On Mineral Processing Process Of Gold Ore Containing Carbon And Arsenic

Though our country has huge huge reserves of gold resources, most of them are refractory gold ores with low grades, which mainly include carbonaceous gold ore, microfine disseminated gold ore and multi-metal sulfide gold ore. Among them, gold ore containing carbon and aresenic is very common. But so far, there is still no effective way to deal with them. This article has done some research on the refractory gold ore from Guizhou Nibao which contain carbon and arsenic. By studying the effect of different beneficiation method on the recovery index of this ore, this article finds an effective solution to prevent the effect of carbon and arsenic in mineral processing.Gold grade in this refractory gold ore from Guizhou Nibao is 3.46g/t, with sulphur 5.55% and arsenic 0.37%. The particle size of gold is fine and a little of them embeded in gangue. Content of carbon and clay in the ore is high, which may be flotated together with sulphide ore in flotation and be bad for the recovery of gold. This article studied the experimental conditions of grind fineness, dosage of regulators, the amount of collectors and so on based on flotation test and record their effect to the concentrate grade index. Findings are as follows:Using gravity separation by tabling to throw the waste ahead of flotation, gold grades and metal distribution were too high, so it is inadvisable on this ore to use gravity separation to throw the waste.The result of closed-circuit flotation experiment shows that, gold grades in staged grinding and floatating flow and one-stage grinding and floatating flow were close, and got the best recovery index with one-stage grinding and floatating flow and a grinding fineness of -200 meshes 95%. Because of the high quality of carbon and small grinding fineness, decarburization in advance will make carbon be flotated with gold and hard to be seprated, so it has no obvious effect on reducing the foltation time and the amount of reagent. In conclusion, the flotation flow should be single-stage roughing, four-stage cleaning and three-stage scavenging with 1500g/t water glass,400g/t copper sulfate as regulators and 125g/t ammonium dibutyl dithiophosphate,240g/t ethyl xanthate,35g/t terpenic oil as collectors. Under these conditions experimental index is best which gold concentrate grade reach 13.71g/t and the recovery rate of gold reach 78.24%.Tailings regrinding and reflotating have little effect on the recovery of gold, as it will make the pulp particle size finer and viscosity higher, which is bad for the infiltration and diffusion of cyanide solution and prevent the contract of gold and cyanide, then reduce the leaching rate as a result. Also, whether adding flocculant doesn’t make big difference in subsidence effect, so it enough to let tailings settle naturely in tailing pond.The separation of sulfur and arsenic test shows that, neither floating sulfur with suppression of arsenic nor floating arsenic with suppression of sulfur can acheive the goal, no matter which ways it use, including with antioxidants, ammonium salt lime, sodium humate, sodium sulfite or others in any PH, any inhibitor or any grinding fineness.