High-silicon Low-grade Zinc Oxide Ore Deep Sulfidation Flotation And Tailings Emission Reduction Technology Research

High-silica and low-grade zinc oxide ore is a refractory zinc resources,which can't be treated economically through traditional beneficiation methods or hydrometallurgical process.In this paper,the thermal-chamical surface modification-flotation process followed by magnetic separation and leaching was investigated to recover zinc,lead,iron and silica from the zinc oxide ore in Lanping,Yunnan Province.Firstly,the thermodynamic calculation of the thermal-chamical surface modification process of lead-zinc oxide during sulfidation roasting was carried out.The results show that the sulfidation transition of lead-zinc oxide under roasting conditions using pyrite as vulcanizing agent is feasible in thermodynamic.Compared with the thermodynamic analysis of sulfidation transition of different mental compounds under sulfur atmosphere,the strength of sulfidation transition of lead-zinc oxide ore is feasible in thermodynamic under carbon-sulfur atmosphere.And the SO₂ would not be generate if the appropriate reaction conditions are controlled.Secondly,the thermal-chamical surface modification-flotation test of smithsonite was carried out,the results show that the zinc mineral can be recovered by this process effectively.The surface morphology and composition of smithsonite before and after the thermal-chamical surface modification were analyzed by XRD,SEM-EDS and EPMA.The XRD analyses indicated that the smithsonite was decomposed into zincite at high temperature.After introducing a small amount of pyrite,sphalerite and wurtzite were formed at surface of the obtained zincite.The EPMA and XPS analysis show that the sulfide species including zinc sulfide and zinc disulfide were generated at the zincite surface after surface modification.The film of sulfides was unevenly distributed at the zincite surface,and the average concentration of elemental sulfur at the sample surface increased with increasing of pyrite dosage.Finally,the thermal-chamical surface modification-flotation-magnetic separation-leaching experiments were carried out on the high silica and low-grade zinc oxide ore,the content of Zn and lead were 5.05%and 1.30%,respectively,the optimum parameters were determined.A flotation product containing 17.46%Zn and 3.93%Pb was obtained after closed-circuit flotation experiment,the Zn and Pb recoveries were86.04%and 69.08%,respectively.The flotation tailing was treated by magnetic separation,and an iron product containing 43.45%Fe,the recovery of Fe reached64.87%.Hydrochloric acid leaching was then carried out for the magnetic separation tailing and a raw quartz product containing 81.05%SiO₂ was obtained,the main component of leaching liquor was CaCl₂,which can be used to prepare anhydrous calcium chloride as raw material.