A study was conducted on the precipitation recovery of strontium from brine. In this study, the precipitation behavior of strontium was traced by using radioactive isotope ⁸⁹Sr, and those of calcium and magnesium by EDTA titration.
The separation of magnesium was carried out by applying the difference in the solubility among calcium, strontium and magnesium bicarbonate contained in the solution saturated with carbon dioxide. By bubbling carbon dioxide into slag containing carbonates, about 80% of magnesium was dissolved. After removing the most part of magnesium by carbon dioxide, strontium was separated by adding sodium hydroxide at temperature 80°C. By this procedure, more than 70% of calcium was precipitated as hydroxide, and the precipitation of residual magnesium was complete.
Strontium was then separated as sulfate by adding ammonium sulfate.
The over-all chemical recovery of strontium amounted to 55-60% after the abovementioned separation process.