Preparation of Iron Oxide Yellow with Iron Sulfate Heptahydrate By-product from Production of Titanium Dioxide

Abstract

With ferrous sulfate by-product from the production of titanium dioxide as main raw material, iron oxide yellow was prepared. Not only the effects of mass ratio of NaO H to FeSO 4 ×7H 2 O, initial Fe 2+ concentration, aeration rate and temperature on the seed crystal, but also those of concentration of seed crystal, p H value and initial ferrous sulfate amount on the iron oxide yellow examined. The process conditions were optimized. The results showed that the production was 4.00 g, the productivity was 12.01 g/h, the seed crystal was claybank and colloid when the molar ratio of Na OH to FeSO 4 ×7H 2 O was 0.5, initial Fe2+ concentration 0.7 mol/L, aeration rate 2.5 L/min and temperature 35 ℃ in the preparation stage of seed crystal. Meanwhile, the production was 20.97 g, the productivity was 8.99 g/h, the iron content in oxide was 86.95% when the concentration of seed crystal was 20%, p H value 4.5 5.0, initial ferrous sulfate amount 60 g in the preparation stage of iron oxide yellow. The prepared iron oxide yellow was homogeneous claviform particles with the phase composition of Fe OOH, average diameter 860 nm, and specific surface area 21.98 m2/g, and its quality was over the first grade of industrial standard HG/T 2249-91.