Clean production technology of acid blue 9 dye

The invention discloses a clean production technology of an acid blue 9 dye. The technology mainly comprises the following steps: condensing o-benzaldehydesulfonic acid and N-ethyl-N-(3'-sulfobenzyl)aniline in an acidic medium to generate a leuco compound; oxidizing the leuco compound in a sulfuric acid medium; processing the obtained oxidation solution by liquid caustic soda or soda ash to form a manganese residue precipitate, filtering, neutralizing the obtained filtrate, concentrating, and carrying out spray drying to obtain dye raw powder; and washing the manganese residue, and oxidizing the washed manganese residue by hydrogen peroxide to generate manganese dioxide for cycle use. Compared with routine production technologiess adopting a manganese dioxide oxidation method, the clean production technology disclosed in the invention has the advantages of no exhaust gas, no waste residues and no dye wastewater through oxidizing the manganese residue in the manganese removal process for later use and through changing solid residues into valuables by developing a unique manganese dioxide recovery method.