Preparation And Technology Design Of High-purity Superfine Iron Oxide For Magnetic Materials

7¹0milion tons of FeSO₄·7H₂O are produced as the by-product of titanium dioxidein our country every year. Most of the products are abandoned, which is a waste ofresource and pollution of the environment. Thus, in this thesis high purity ferric oxide formagnetic materials was prepared by liquid phase precipitation method, using by-productof TiO2–ferrous sulfate, Ammonium bicarbonate and ammonia as raw materials. In thiscondition, it can not only develop the production process of high-grade iron oxide andreduce the production cost, but also optimize the resource and protect environment.The purification of ferrous sulfate from by-product of titanium dioxide, the synthesisof high purity ferric oxide for magnetic materials and the process design of2000t/a highpurity iron oxide for magnetic materials were studied in this thesis.In the ferrous sulfate-purified experiment, the purification technology and the purityof product were improved by adding the soaking process. The best range of hydrolysis pHis5.1⁵.3and0.33%nonionic polyacrylamide was choosed for flocculation treatment.The best process conditions of synthesizing high-purity iron oxide for magneticmaterials are that the mole ratio of FeSO₄, NH₄HCO₃and NH₃is1:0.8:0.5, which is usedfor raw materials. the raction temperature is40℃,the concentration of ammoniumbicarbonate is20%, the Concentration of ferrous sulfate is2.4².8mol/L, When50mLferrous sulfate is prepared, the feeding speed of NH₄HCO₃and NH₃Mixed liquid is2mL/min in the first1/3time and then is maintained3mL/min in the remaining time, andthe calcination temperature is800℃. Under these conditions, the purity of α-Fe₂O₃with100nm can reach99.4%. In addition, the results showed when the reactant alkali ratioincreased, products changed from a ball into a dumbbell, meanwhile, its axial ratioincreased and the activity of production decreased.In the process design stage of2000t/a high purity iron oxide for magnetic materials,the process route was determined and the process flow diagram was maked; the materialsthrough the process and the equipments were calculated and the the composition of thefeed and the discharge was got to form the material flow chart; the selected equipmentswere showed in the equipment list.The problems of industry production are studied in this paper, which has a greatpractical value.