METHOD FOR PRODUCING NITRITE SALTS CONTAINING AMMONIA FROM USED NITRITE

摘要

The present invention relates to a method for producing nitrate salts containing high value-added ammonia by recycling waste nitric acid containing aluminum salts and ammonium salts. The present invention comprises: a) a first step of generating sludge; b) a second step of separating the sludge into a nitrate liquid containing ammonia and insoluble compounds using a filter press; c) a third step of concentrating the nitrate liquid containing ammonia, followed by cooling and concentration adjustment, thereby collecting the nitrate liquid containing ammonia; d) a fourth step of precipitating the nitrate liquid containing ammonia; e) a fifth step of collecting the nitrate liquid containing ammonia; and f) a sixth step of recycling the same to the fourth step. The filter press comprises a filter part including: a pair of filter frames provided at one side and the other side of the filter press; a compression plate provided between the filter frames; and filter cloths provided between the filter plates and the compression plate. A predetermined first pattern is formed on an inner surface of the filter frame and a predetermined second pattern is formed on the counter surface of the compression plate, which faces the inner surface. The second step comprises a compressing and filtering step of supplying a compression fluid to the compression plate to expand the compression plate, and compressing and filtering the sludge to discharge the nitrate liquid from the sludge through the compression plate.