Preparation of polymeric ferric sulfate?

Production of solid polyferric sulfate method there are two main types: direct oxidation process (steps) and spray drying. Its production process by direct oxidation was added to the oxidizing furnace in ferrous sulfate, dehydration in the heat oxidized to sulfate carbonate hydroxide; mixed with sulfuric acid reactions, after curing pieces, made of solid polyferric sulfate. The process is simple, low material consumption, but due to the graininess is difficult to complete oxidation of ferrous sulfate, Fe2, low oxidation rates and products insoluble in many, it is difficult to meet the requirements of national standard. Spray drying is a qualified liquid product with high speed centrifugal spray dryer (or pressure spray drier) dehydrated, products fully comply with GB14591-93 requirements. Spray drying method and direct method of difference is that former products of total iron content is high, at 23.5%, about 19% 4.5% higher than the latter, and Fe2 have been fully oxidized, insoluble matter content is low, the low levels of heavy metals, can reach targets even more than foreign products.