Process for the production of sodium carbonate anhydrate

A process for the production of sodium carbonate anhydrate having a bulk density of at least 800 kg/m3, said process comprising:

• providing a suspension of solid sodium carbonate and/or solid sodium bicarbonate and/or solid double salts at least comprising one of sodium carbonate and sodium bicarbonate, in a mixture containing water and an at least partly water miscible organic solvent, which solvent influences the transition temperature below which sodium carbonate monohydrate is stable, whereby said solvent and the amount of said solvent are selected such that the said transition temperature is below the boiling point of the said mixture of water and said at least partly water miscible organic solvent and wherein said solvent comprises at least about 5 wt. % of the combined weight of the water and solvent,
• wherein if sodium bicarbonate is present, converting the sodium bicarbonate into sodium carbonate at a temperature above said transition temperature and below the boiling point, whereby the sodium bicarbonate decomposes into sodium carbonate, carbon dioxide and water,
• providing a suspension temperature in the suspension that is below the transition temperature for a time period effective to convert the sodium carbonate to crystals of sodium carbonate monohydrate,
• increasing the temperature to and maintaining the temperature of the suspension at a temperature above the said transition temperature and below the said boiling point in order to recrystallize the sodium carbonate monohydrate crystals into crystals of sodium carbonate anhydrate from said mixture, and
• recovering the sodium carbonate anhydrate.