PURPOSE: To efficiently produce a non-corrosive or extremely low-corrosive iron based coagulant.
CONSTITUTION: Iron polysulfate is obtained by partially neutralizing ferric sulfate by ferric trioxide hydrate such as akaganeite. A manufactured ferric sulfate can be used as the raw material or ferric sulfate can also be formed by reacting the akaganeite with sulfuric acid to form ferric sulfate and at the same time to induce a reaction partly neutralizing ferric sulfate. Since the partial neutralization reaction of ferric sulfate proceeds rapidly in according with the reaction formula, the reaction time is reduced and iron polysulfate is efficiently produced and the obtained iron polysulfate is non-corrosive or extremely low corrosive. (3-x)Fe2(SO4)3+2xFeOOH+2xH2O→3 Fe2(SO4)(3-x)(OH)2x.
SUZUKI MICHIMASA
AWAYA MASARU
