'an improved process for the preparation of highly pure ferrous sulfate heptahydrate and ferrous sulfate monohydrate'

摘要

The present invention relates to an improved process for the preparation of highly pure ferrous sulfate monohydrate comprises reacting iron powder with aq. solution of sulfuric acid at 40-80°C. After completion of reaction, insolubles were filtered out, filtrate solution was concentrated to low volume under vacuum at 50-60°C & the resulting slurry was gradually cooled to 0-5°C. The bluish-green colored crystalline solid of ferrous sulfate heptahydrate of Formula II was filtered out, washed with cold water and dried at ambient temperature. The pure ferrous sulfate heptahydrate was then dried under vacuum at 60-80°C to obtain highly pure ferrous sulfate monohydrate of Formula I. FeS04.xH2O FeS04.7H2O Formula I Formula II