Ferrous sulfate heptahydrate (copperas) was recovered by treating spent pickle
liquor with tertiary butyl alcohol. Yields of crystallized ferrous sulfate heptahydrate
were calculated for different concentrations of liquor at temperature of 25 & 35°C. It is
concluded that for the most complete recovery of ferrous sulfate heptahydrate from
waste rickle liquor by adding tertiary butyl alcohol, the HzS04 concentration should be
as low as possible, the FeS04 concentration as high as possible, the alcohol to liquor
volumetric ratio of 2:l and temperature of 25°C. For a liquor containing 135 g/l of
FeS04 and LO g/l of &SO4, the yield was 94.2% using 2: 1 volumetric ratio at 25OC.
Key Words: Waste pickle liquor, Pickling of steel, ferrous sulfate heptahydrate (copperas).