ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Solubility of (NH₄)Al(S0₄)₂ .12H₂0 in the Systems H₂0—(NH₄)Al(S0₄)₂—H₂S0₄ and H₂0—(NH₄)Al(S0₄)₂—H₃P0₄ at the Temperatures of 20 °C and 30 °C and Vapour Pressure above these Systems

A. Žúžiova, Van Viet, V. Khandl, and P. Fellner

Department of Inorganic Technology, Faculty of Chemical Technology, Slovak Technical University, SK-812 31 Bratislava

Abstract: Influence of concentration of H₂SO₄ and H₃PO₄ On the solubility of (NH₄)Al(SO₄)₂ . 12H₂O in aqueous solutions and vapour pressure above saturated solutions of the systems H₂O-(NH₄)Al(SO₄)₂-H₂SO₄ and H₂O-(NH₄)Al(SO₄)₂-H₃PO₄ was investigated. The measurements were carried out at the temperatures of 20°C and 30°C. It is shown that in the system H₂O-(NH₄)Al(SO₄)₂-H₂SO₄ solubility of (NH₄)Al(SO₄)₂ . 12H₂O increases with increasing concentration of H₂SO₄ up to 8 mass % H₂SO₄. When concentration of the acid further increases, solubility of (NH₄)Al(SO₄)₂ . 12H₂O decreases. However, from the concentration of ca. 35 mass % H₂SO₄ it starts to increase again. At high concentrations of sulfuric acid (> 30 mass %) it is Al₂(SO₄)₃ . 16H₂O and not(NH₄)Al(SO₄)₂. 12H₂O which is in equilibrium with the solution. Water vapour pressure above the solutions shows how the activity of water changes with composition of the investigated systems.

Full paper in Portable Document Format: 494a173.pdf

Chemical Papers 49 (4) 173–175 (1995)