Abstract: In a process for purifying raw brine containing dissolved strontium, calcium and magnesium impurities wherein the raw brine is treated by contacting the brine with sodium carbonate for precipitation of strontium and calcium carbonate, contacting the brine containing the strontium and calcium carbonate solids with sodium hydroxide for precipitation of magnesium hydroxide, and removing strontium carbonate, calcium carbonate and magnesium hydroxide solids from the sodium chloride brine, the improvement which comprises passing at least a portion of said removed solids to the zone wherein the raw brine is contacted with sodium carbonate.

Abstract: Processes for decreasing mercury butter formation in mercury electrolytic cells employing brine which contains strontium wherein the brine is treated to lower the strontium content to 0.5 ppm or less. The removal of strontium from the brine may be effected by treating the brine with an ion exchange resin in sodium form to adsorb strontium thereon. Alternatively, strontium may be removed by treating the brine with a water-soluble metal hydroxide, subjecting the resulting mixture to partial evaporation to produce sodium chloride as precipitate and saturated brine solution and admixing the precipitate with water to form brine for electrolysis.