Silicon tetrafluoride byproduct separation process

A process for recovering useful compounds from a byproduct composition produced in a silicon tetrafluoride production process, comprising:

• calcining a byproduct composition comprising sodium sulfate and aluminum sulfate and forming an oxidized phase mixture comprising alumina solids, and sodium sulfate and a gaseous phase comprising sulfur trioxide;
• absorbing the gaseous sulfur trioxide in a mixture of sulfuric acid and water to produce oleum;
• cooling the oxidized phase mixture to produce a cooled solid phase mixture;
• mixing the cooled solid phase mixture with water to produce a dissolved product comprising dissolved sodium sulfate and suspended alumina solids;
• filtering the dissolved product to obtain a cake comprising alumina and a sodium sulfate salt solution;
• crystallizing the sodium sulfate salt solution to produce steam condensate and a sodium sulfate sludge;
• drying the cake to produce alumina solids;
• and
• drying the sludge to produce a dry sodium sulfate salt.