Pyrite Residue Hydrothermal Preparation Of Iron Oxide Technology

Ferric oxide is a kind of abio-nonmental material. With its innocuity, no pollution, resistting ultraviolet radiation, it is always used as the material of making magnetism record, ferrite magnetic material and polish.The technical conditions of preparing Fe₂O₃ by hydrothermal method from pyrite cinders were studied in the paper. The total iron and ferrous contents of dried hydrothermal products, rate of solution filtration, ferric-loss content were effected by reaction temperature, reaction time, solution pH, total ferric concentration, nFe²⁺/nFe³⁺. The proper condition was that: reaction temperature is at 190℃, reaction time is 30min, pH is 7.0, total ferric concentration is 3.0mol/L, nFe²⁺/nFe³⁺ =0.145. According to the technical condition, the product was obtained with total its ferric content is 66.26%,ferrous content is 2.5%,ferric-loss is 0.83%,the rate of solution filtation is 60mL/min. The phase of product is Fe₂O₃ and Fe₃O₄ and the particles are spherical.The effect of additive on Fe₂O₃ prepared by hydrothermal method was studied in this lecture. The experiment results demonstrated that citric acid, tartaric acid, OP, CTAB, NaH₂PO₄, slow down the speed the rate of solution filtration while the addition of SDS, PVP, CO(NH₂)₂ speed up the solution filtration rate. The CO(NH₂)₂ was choosen as the proper additive due to adding SDS causing so much bubble which was adverse for the industry production, and PVP was so expensive that we had to give it up.At the existence of CO(NH₂)₂, the proper technical condition is that: reaction temperature is 140℃, reaction time is 30min, pH is 7.0, nFe²⁺/nFe³⁺=0.145, the content of the CO(NH₂)₂ is 0.72/200ml. According to the technical condition, the product was obtained with total its ferric content is 65.09%,ferrous content is 2.49%,ferric-loss is 0.66%,the rate of solution filtation is 34mL/min. The phase of product is Fe₂O₃, FeOOH and Fe₃O₄ , the particles are spherical. The concentration of (NH₄)₂SO₄ is 28-30%, Fe²⁺ is 0.001mol, Fe³⁺ is 0.002mol. The feasible condition of recovering (NH₄)₂SO₄ is that: pH is 9, H₂O₂: filtration solution(Volume)= 1:200.According to the recovering condition, the quality of (NH₄)₂SO₄ reaches to GB535-1995.