Research On Beneficiation Difference And Mechanism Of Different Magnetization Roasting Products Of Jiugang Powder Ore

Magnetization roasting technology is currently effective methods for processing complex and refractory iron ore.Muffle furnace magnetization roasting and suspension magnetization roasting are two typical magnetization roasting methods.The study on the phase composition,magnetic properties,structure and surface properties of the two kinds of magnetization roasting products and concentrates not only provides technical support for the sorting of refractory iron ore,but also has important significance for the in-depth understanding of magnetization roasting theory.Jiugang powder ore(0～15 mm)was taken as the research object in this article,aiming at two different method of static muffle furnace magnetization roasting and fluidized suspension magnetization roasting,the principle process of magnetization roasting-grinding-magnetic separation-reverse flotation was adopted.With the aid of some detection means,such as XRD,SEM,VSM,Mossbauer spectrum analysis and FTIR,etc,the differences in phase composition,magnetic properties,structure and surface properties of the products of the two processes were analyzed in combination with characterization.The relationship between different magnetization roasting processes and product selectivity differences is constructed.The suitable conditions of the muffle furnace magnetization roasting was that roasting time was 40 min,the temperature was 650℃,and the coal ratio was 3%;the suitable conditions of the suspension magnetization roasting process was that roasting time was 10 min,the temperature was 570℃,and the content of CO was 20%.After magnetization roasting,Hematite(limonite)and siderite in the ore were mainly transformed into magnetite.Under the conditions that the grinding fineness-0.043 mm was the content of 90%,and the magnetic field strength was 139.26 kA/m.The iron grade of the magnetic separation concentrate of the muffle furnace magnetization roasting products was 53.23%,and the iron recovery rate was 92.58%;the iron grade of the magnetic separation concentrate of the suspension magnetization roasting products was 56.75%,and the iron recovery rate was 87.23%.The suitable conditions of the reverse flotation process of magnetic separation concentrate of muffle furnace magnetization roasting products:the amount of collector was 360 g/t,the amount of caustic starch was 700 g/t,the pH of the slurry was 7.5,and the closed circuit was passed through one coarse,one fine and three sweeps.In the flotation test,the iron concentrate with the grade of 57.76%and the recovery rate of 98.41%was obtained.The suitable conditions for the reverse flotation process of magnetic separation concentrate of suspension magnetization roasting products:the amount of collector was 300 g/t,the amount of caustic starch was 400 g/t,the pH value of the pulp was 7.5,and the closed-circuit flotation was carried out through one coarse,one fine and three sweeps.In the flotation test,the iron concentrate with the grade of 58.02%and the recovery rate of 98.39%was obtained.The study of particle size,specific surface area and pore structure of the magnetization roasting products shows that the sintering phenomenon in the muffle furnace magnetization roasting products is more serious than that of the suspension magnetization roasting products.The particle size of the muffle furnace magnetization roasting products is larger than that of the suspension magnetization roasting products.The shape and size of the channel of the muffle furnace magnetization roasting products are more complex than those of the suspension magnetization roasting products.Therefore,in the early stage of grinding,in the same grinding time,the grinding fineness of the muffle furnace magnetization roasting products is finer than that of the suspension magnetization roasting products.The content of magnetite in the magnetic separation concentrate of the muffle furnace roasting products is 85.2%,and the content of maghemite is 12.8%;the content of magnetite in the magnetic separation concentrate of the suspension roasting products is 75.7%and the content of maghemite is 21.5%.Therefore,the iron grade of the magnetic separation concentrate is higher and the recovery rate is lower.At the same time,the isomorphism of magnesium and manganese ions replace iron ions in the crystal lattice,which will reduce the iron grade when magnetic separate and flotation separate.The adsorption characteristics of the magnetic separation concentrate of the different magnetization roasting products shows that the caustic starch is adsorbed on the surface of the magnetite in the magnetic separation concentrate,and the collector is adsorbed on the surface of the quartz in the magnetic separation concentrate,the adsorption capacity of the magnetic separation concentrate of the muffle furnace roasting product is 122.02×10-3 mg/g,the adsorption capacity of the magnetic separation concentrate of suspension roasting products is 59.86×10-3 mg/g.This paper systematically studies the differences in the selectivity of products from the muffle furnace magnetization roasting and the suspension magnetization roasting.It not only provides theoretical support for the magnetization roasting and separation process of refractory iron ore,but also enriches the theoretical system of magnetization roasting.