Solid-solid reactions in the Ca3(AsO4)2-Ca2SiO4-CaSO4 ternary system at elevated temperatures

Exploratory laboratory-scale tests were performed in order to identify the solid phases present in the Ca2SiO4-Ca3(AsO4)2 binary system and in the Ca2SiO4-Ca3(AsO4)2-CaSO4-CaO system. A microanalysis study from slow-cooled samples suggests the presence of at least two intermediate phases. These compositions correspond to Ca5(AsO4)2(SiO4) (1:1) and Ca8(AsO4)4(SiO4) (1:2). The formation of stable intermediate salts with high melting points is of significant industrial interest in copper converting operations. If excessive amounts of solids form, skimming problems or poor slag-metal separation may become problematic.