高温におけるＦｅ２（ＳＯ４）３溶液の加水分解に関する湿式冶金学的研究（第４報） 高温におけるＦｅ２（ＳＯ４）３溶液の加水分解に及ぼすＮａ２ＳＯ４の影響

Abstract

Hydrolysis of acidic ferric sulphate solutions of various concentrations with the addition of sodium sulphate has been investigated in an autoclave at temperatures of 185°C and 200°C.The results obtained were as follows:1. When the hydrolysis of ferric sulphate solutions was at equilibrium, the concentration of ferric ion increased with an increase in sulphuric acid concentrations, while at the same sulphuric acid concentration, the concentration of ferric ion decreased considerably with an increase in the addition of sodium sulphate.2. In the absence of sodium sulphate, hydrolysis and precipitation of ferric oxide, Fe2O3, occurred at lower sulphuric acid concentrations, and ferric basic sulphate, Fe (OH) SO4, was precipitated at higher concentrations of sulphuric acid, while with the addition of sodium sulphate in the ferric sulphate solutions, hydrolysis and precipitation of sodium jarosite, NaFe3 (SO4) 2 (OH) 6, occurred at higher concentrations of sulphuric acid.3. At a temperature of 185°C, when respectively about 7.5g/l Na+ ion, 15g/lNa+ ion and 30g/l Na+ion as sodium sulphate were added in the ferric sulphate solutions, hydrolysis and precipitation of ferric oxide occurred up to the sulphuric acid concentration of 22.8g/l or below, 29.7g/l or below and 48.3g/l or below, while at those or above, sodium jarosite was precipitated.4. At a temperature of 200°C, when respectively about 15g/l Na+ion and 30g/l Na+ ion as sodium sulphate were added in the ferric sulphate solutions, hydrolysis and precipitation of ferric oxide occurred up to the sulphuric acid concentration of 36.5g/l or below and 60.4g/l or below, while at those or above, sodium jarosite was precipitated.