INVESTIGATION OF BINARY MIXTURES OF SOLID SOLUTIONS Al₂(SO₄)₃·16 H₂O, CaSO₄·2H₂O AND Na₂SO₄ WITH MgHPO₄?3H₂O

Abstract

We analyzed thermal phase changes (20°-1000°C) of binary mixtures of Al₂(SO₄)₃·16 H₂O(I), CaSO₄·2H₂O (II) and Na₂SO₄ (III) with MgHPO₄·3H₂O (IV). Thermal differential analyses (TG, DTG, DTA), IR, WAXS and thermorentgenography revealed that above mentioned mixtures heated during one hour up to 500°C and to 1000°C changed their structures. From among these three system of binary mixtures (I-IV; II-TV, III-IV) only (Na₂SO₄-MgHPO₄· 3H₂O), when the participation share of Na₂SO₄ was from 80 to 30% in the binary mixture, showed the formation NaMg₄(PO₄)₃ with coexistence Na₂SO₄-Mg₂P₂O₇ in samples.