高温におけるFe₂(SO₄)₃溶液の加水分解に及ぼすZnSO₄の影響について

高温におけるFe₂ (SO₄) ₃溶液の加水分解に関する冶金学的研究について(第2報)

抄録

Hydrolysis of acidic ferric sulphate solutions of various concentrations with the addition of zinc sulphate has been investigated in an autoclave at the 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 final concentrations of iron in the solutions increased with the increase of sulphuric acid concentrations, but at the same sulphuric acid concentrations, those of iron decreased considerably with the addition of zinc sulphate.
2. In the hydrolysis of ferric sulphate solutions, ferric oxide, Fe₂O₃, was precipitated at lower sulphuric acid concentrations. But the stable region of ferric oxide was extended with the addition of zinc sulphate in the ferric sulphate solutions.
3. In the hydrolysis of ferric sulphate. solutions at 185°C in the absence of zinc sulphate, Fe₂O₃is stable below 55.8g/l H₂SO₄, and Fe (OH) SO₄is stable above 55.8g/l H₂SO₄. When zinc sulphate was added to the solutions, Fe₂O₃is stable'over a wide range of conditions. For example, at 185°C, when respectively about 70g/1 Zn and 100g/l Zn as zinc sulphate were added, F_e2O₃is stable up to 84.2g/l H₂SO₄and 93.0g/l H₂SO₄.
4. In the hydrolysis of ferric sulphate solutions at 200°C, in the absence of zinc sulphate, F_e2O₃is stable below 69.3g/l H₂SO₄, and Fe (OH) SO₄is stable above 69.3g/l H₂SO₄. When respectively about 70g/l and 100g/l Zn as zinc sulphate were added, F_e2O₃is stable up to 103.8g/l H₂SO₄and 112.5g/l H₂SO₄.
5. When zinc sulphate was added to the solutions, the relations between the concentrations of iron and those of sulphuric acid over the ferric oxide stable region are expressed _by the following experimental equations. At the temperature of 185°C log [F_e (g/l)] =4.91 log [H₂SO₄ (g/l)]-8.93 about 70g/l Z_nas zinc sulphate log [Fe (g/l)] =8.21 log [H₂SO₄ (g/l)]-15.28 about 100g/l Z_nas zinc sulphate At the temperature. of 200°C log [F_e (g/l)] =3.82 log [H₂SO₄ (g/l)]-7.23 about 70g/l Z_nas zinc sulphate log [F_e (g/l)] =5.46 log [H₂SO₄ (g/l)]-10.31 about 100g/l Z_nas zinc sulphate
6. The equilibrium diagram of the ternary system Fe₂O₃-SO₃-H₂O in the presence of zinc sulphate at 185T, and 200°C were established from the experimental data.