INFLUENCE OF TEMPERATURE (20^o-1000^oC) ON THE PHASE CHANGES IN Li₂CO₃ - MgHPO₄•3H₂O SYSTEM

Abstract

We analyzed thermal phase changes of substrates (20^o-1000^oC) of binary mixtures Li₂CO₃ - MgHPO₄•3H₂O prepared with a percentage molar ratio of 90%-10%. The research was done using differential thermal analysis (TG, DTG, DTA), IR-spectrophotometry and WAXS. The above-mentioned substances changed the structure when heated for 1 h up to 500^oC and 1000^oC. MgHPO₄•3H₂O (Newberyite) changes its structure at 500^oC into not completely formed Mg₂P₂O₇ and at 1000^oC) into Mg₂P₂O₇. Lithium carbonate (20^o - 1000^oC) does not change its structure. Binary mixtures change the structure depending on the molar ratio and at 1000^oC they form Li₃PO₄, LiMgPO₄, MgO and Mg₂P₂O₇. At the molar ratio of 90% Li₂CO₃ - 10% MgHPO₄•3H₂O they form a sinter with the porcelain of the melting pot.