Solubility of Na−F−SO4 in Water and in Sodium Hydroxide Solutions

Solubility was measured in the Na−F−SO4 system at 25 °C and at 50 °C. Pure-component solubilities for NaF and Na2SO4 are in agreement with available literature data at 25 °C and at 50 °C. The influence of sodium hydroxide on the solubility of the sodium−fluoride−sulfate double salt (Na3FSO4) was also examined. The solubility of the double salt was decreased as the concentration of sodium hydroxide in solution increased.