Waste sulfuric acid of about 30%~35% concentration was heated to 90℃~100 ℃, then the iron slurry was introduced with stirring, followed by filtration, decolorization, crystallization and dehydration at 300℃, to give ferrous sulfate as a white powder; the purified ferrous sulfate was baked at 800C for 2-2.

Study on preparation of reduced iron powder using copperas;

An experimental study of carbon-reduction process in preparing reduced iron powder using V-Ti magnetite concentrate;

With some domestic hematite and magnetite ores as the raw materials,sponge iron powder with high performance can be obtained adopting Hgans C-H two-stage reduction technique,and hydrogen-reduced iron powder can be prepared after a further hydrogen reduction process.

A novel recovery process for removing NO from flue gas with the recovery process of absorption with acid following complexation with ferrous chelate in aqueous solution and reduction with iron powder was proposed.

Effect of EDTA,fulvic acid and acetate addition on microbial iron reduction in paddy soils;

Now some research said the process of iron oxide anaerobic reduction is mainly a microbial dissimilatory iron reduction.

Especially, the process of iron reduction has not only an important effect on the basic attribute of paddy slurry but also an unusual significance in the way of soil environment chemistry.

A study on chloronitrobenzene manufacture wastewater treatment with sequential a naerobic-aerobic process: Performances of Fe/C reduction integrated with A/O pr ocess;