Experimental Study On Secondary Recovery Of Gold Tailings

Gold is non-renewable resource.With continuous exploitation,reserves of gold are decreasing year by year.And in actual gold mining and sorting process,a large number of high-value gold tailings are produced by mining enterprises and are not treated effectively,which causes the waste of resources.The gold deposits in Qinling Mountains area are mainly fine grained gold bearing sulfide ores,and the gold loss of tailings is serious;The main problems include that gold in tailings exists in form of microgranular enclaves and sulfide ore is oxidized,all these problems lead to difficulty in separation.It is of great significance for rational use of resources to achieve good recovery of gold in tailings.In this paper,a gold bearing pyrite tailing from Songxian,Henan Province was studied.And analysis of grain size,chemical element analysis,chemical phase analysis and mineral composition analysis were carried out to investigate its properties.According to its ore properties,the field test research,flotation experiments were carried out,and the grinding fineness,flotation time and flotation concentration were finally determined.Basing on this,the reagent system and flotation process were studied;In the end,the optimized flotation tests were carried out,the BK301 and cyclonic static micro bubble flotation column were used to improve flotation efficiency which achieved the purpose of secondary recovery of resources.According to the experimental study on process mineralogy of ore analysis,experimental study on flotation of actual mineral with laboratory flotation machine was conducted.Through experimental exploration,the process of "one roughing,two concentrating and two sweeping" was finally determined.By single factor optimization method,the optimum conditions were determined as follows: flotation fineness of-0.045 mm accounting for 90%,flotation pulp concentration of 30%,5min of flotation time;roughing reagent system for Na2CO3 200 g/t,water glass 80 g/t,and oxalic acid 600 g/t,copper sulfate 20 g/t,isoamyl xanthate 75 g/t,ammonium dibuyl15 g/t,2# oil 15 g/t;concentration reagent system: water glass 20 g/t,isoamyl xanthate 20 g/t,ammonium dibuyl 15 g/t for primary;water glass 20 g/t for second;sweeping reagent system: isoamyl xanthate 20 g/t,ammonium dibuyl 10 g/t for primary;isoamyl xanthate 20 g/t,ammonium dibuyl 10 g/t for second.“One roughing-two concentrating-two sweeping closed circuit” was made,and theconcentrate grade of Au 8.68 g/t and the flotation recovery of Au 67.44% were finally obtained.Through the new collector BK 301 and cyclone static micro-bubble flotation column,one roughing was carried out,the test obtained the 1.72 g/t grade of coarse concentrate,the 76.53% recovery of coarse concentrate.To improve the flotation index,the optimization open circuit test of “one roughing-two concentrating-one sweeping of collaboration of flotation column and flotation cell” was carried out and the final concentrate grade of Au was 9.45 g/t,the flotation recovery of Au was51.01%.Compared to the flotation machine "one roughing-two concentrating-two sweeping" process,concentrate grade increased by about 0.50 g/t,and recovery increased by about 4%.The study provides the basis for secondary recovery of gold bearing pyrite tailings in the area.