Experimental Study On Recovering Pyrite From Chengchao Iron Tailings

Iron ore tailings is a major part of China's industrial solid waste,has two notable features of large quantity of emission and low utilization rate.Comprehensive utilization of iron ore tailings can save resources,prevent water pollution and extend the service life of tailings ponds.Chengchao iron tailings annual production amount reachs 5 million tons,and a large amount of tailings not only occupies the large area land,but also pollutes the environment.Chengchao iron tailings had pyrite with high grade,this paper optimized reagent system of recovering sulfur from Chengchao iron tailings by orthogonal experiment.The study included conventional flotation test and electrochemistry flotation test,and mechanism analysis of flotation reagent for pyrite.Recovering pyrite from Chengchao iron tailings could bring certain economic benefits for enterprises,on the other hand,it was conducive to the whole utilization of iron ore tailings.Conventional flotation test results showed that flotation time was the most significant factor influencing roughing recovery,the dosage of pine camphor oil was a significant factor,the dosage of copper sulfate and the dosage of sodium n-butyl xanthate were not significant factors.The optimum reagent condition was that the dosage of copper sulfate was 800g/t,the dosage of sodium n-butyl xanthate was 330g/t and the dosage of pine camphor oil was 120g/t.A sulfur concentrate with yield of 26.68%,grade of 48.36% and recovery of 83.93% was obtained after closed-circuit process involving one roughing,one cleaning and two scavenging.Electrochemical flotation test results showed that flotation time was the most significant factor influencing roughing recovery,the dosage of pine camphor oil and the dosage of sodium sulfide were significant factors.The optimum reagent condition was that the dosage of sodium sulfide was 550g/t,the dosage of copper sulfate was 800g/t,the dosage of sodium n-butyl xanthate was 125g/t and the dosage of pine camphor oil is 70g/t.A sulfur concentrate with yield of 26.54 %,grade of 48.64% and recovery of 83.45% was obtained after closed-circuit process involving one roughing,one cleaning and two scavenging.In this paper,the mechanism of flotation reagent for pure pyrite was discussed by using the methods of Zeta potential,FTIR and XPS.It showed that in distilled water(p H=6.5),pyrite can not be recovered from Chengchao iron tailings with sodium sulfide alone,possibly because it generated limited elemental sulfur on pyrite surface;sodium n-butyl xanthate reacts with pyrite to produce hydrophobic xanthate iron on its surface,thus achieving collector performance to pyrite.