METHOD OF PREPARING SODIUM PYROSULFITE Russian patent published in 2000 - IPC

FIELD: chemical industry, more particularly preparation of sodium pyrosulfite. SUBSTANCE: method comprises reacting calcined soda with sodium hydrosulfite, treating the resulting sulfite- hydrosulfite suspension with sulfur dioxide to prepare suspension of sodium pyrosulfite and isolate the desired product. Sulfur dioxide, which results from combustion of sulfur in excessive amount of air. The resulting hot sulfur dioxide is first allowed to pass through suspension of sodium pyrosulfite under conditions that allow for complete dehydration of suspension of sodium pyrosulfite. Moistened sulfur dioxide is fed into sulfite-hydrosulfite suspension. Invention makes it possible to simplify process and reduce power consumption. EFFECT: more efficient preparation method. 6 cl, 1 dwg, 3 ex