Abstract: A process is described for recovering sodium carbonate or other sodium-based chemicals from sodium-bearing streams, including in particular mine water, evaporative pond water and sodium carbonate decahydrate deposits, recycle and purge streams, and other waste streams. In the process sodium bicarbonate-bearing streams are decarbonized to reduce the sodium bicarbonate concentration in a combination with other sodium-bearing streams, resulting in a liquor suitable as feed to a sodium carbonate decahydrate or sodium carbonate monohydrate process. The sodium bicarbonate stream is combined in a mix tank with other sodium carbonate bearing streams where the concentration is adjusted to form a liquor suitable to feed a sodium decahydrate or sodium carbonate monohydrate evaporation/crystallization step. In the process the combination of the various sodium-bearing streams is decarbonized to below 3.