Process for the recovery of the sodium hydroxide and sodium chloride from the effluent of a diaphragm cell as solid sodium bicarbonate

摘要

The present invention relates to a method and process for recovering solid sodium bicarbonate, from the effluent, of the cathode compartment of a diaphragm cell that contains sodium hydroxide and sodium chloride. The effluent is treated with carbon dioxide and ammonia to essentially convert the sodium hydroxide to sodium bicarbonate. Thereafter, the effluent is treated to decompose the ammonium chloride to evolve and recycle ammonia without the formation of pollutants, the treated effluent, free of NH.sub.3, CO.sub.2 and alkali, is resaturated and sent to the anode compartment of the diaphragm cell. In preferred embodiments, all of the steps are interconnected and the materials produced are recycled, such that the only products produced are chlorine, hydrogen and sodium bicarbonate, without waste products in a continuous process.