Recovery of sodium nitrite from by-product process liquors containing sodium chloride

摘要

According to the present invention, sodium nitrite is recovered from an aqueous solution containing dissolved sodium nitrite and sodium chloride by a process which comprises subjecting said solution to crystallization in a first crystallization zone under conditions sufficient to effect crystallization of sodium chloride, including operating at temperatures of from about 110° to 130°C, to produce a first slurry containing sodium chloride crystals; separating said crystals from said first slurry to produce a solution containing dissolved sodium nitrite; subjecting said sodium nitrite solution to crystallization in a second crystallization zone under conditions sufficient to effect crystallization of sodium nitrite from said solution, including operating at temperatures of from about 10° to 60. degree. C, to form a second slurry containing sodium nitrite crystals; and recovering said sodium nitrite crystals from said second slurry.