3fe 2(SO4)3+ 12H2O+na2so 4 = na 2 Fe 6(SO4)4(oH) 12+6h2so 4

If the solution to be treated contains a lot of sulfate ions, iron can be precipitated in the form of yellow jarosite in the presence of sodium ions, methyl ions or ammonia ions by controlling the reaction PH to be about PH= 1.5 and the reaction temperature to be between 80-95. It can be seen from the reaction equation that sulfuric acid will be generated during the reaction, so in order to control the PH value, the sodium salt containing sulfate or sulfite can be used to adjust the pH value, and the second sodium salt can be used to adjust the pH value.