Synthetic tests of polyferric sulfate (PFS) is carried out in this paper. The effects of the operation temperature

pressure

dosages of sulfuric acid and catalysts on reaction rate and quality of product are investigated . The results indicate that the effect of temperature on reaction rate is like a parabola with a downward curvature

and the homologous best temperature is about 120 ℃. The reaction rate for synthesis of PFS is directly proportional to the dosage of catalysts and increases progressively with increasing dosage of sulfuric acid as well

but the rate increase will become unremarkable unless the pressure is less than 0.3 MPa. When the molar ratio of sulfuric acid to ferrous ion is in the range of 0.25—0.50

the alkalinity degree of the final product will increase with the decrease of sulfuric acid dosage. Once when the molar ratio is less than 0.25

the alkalinity degree and ferric content will remarkably decrease and a lot of ferric hydroxide precipitates.