Add 5500L of industrial hydrochloric acid with 25% mass fraction and 1500kg of aniline solid waste filter cake to the reactor, stir for 1 hour and then transfer the mixture to the oxidation pot for filtration; the aniline solid waste filter cake includes 25wt% of sodium hydroxide, 74wt% of ferrous hydroxide, and 1wt% of black aniline;
Heat the mixture to 87, then press the filtrate in the filter press for 3 hours; put the filtrate into the reduced pressure distillation kettle and adjust the temperature of the reduced pressure distillation kettle to 40. 87 in the filter press for 3 hours of filtration, the pressure of said filtration is 5MPa; the obtained filtrate into the decompression distillation kettle to adjust the temperature of said decompression distillation kettle to 40 , 200kg of sodium chlorate in stirring conditions in four batches to add to the decompression distillation kettle for the reaction, to obtain the mass fraction of 30% of the ferric trichloride solution; the time interval between the addition of sodium chlorate to the adjacent two batches is 15 minutes; to get the sodium chlorate The time interval between two adjacent batches of addition of sodium chlorate is 15 minutes; the ferric chloride solution obtained is detected by halo ring method with potassium ferricyanide, and said ferric chloride solution does not contain Fe2+; the filter residue obtained by the above pressure filtration is analyzed, and said filter residue can be used as alcohol-soluble aniline black;
Aniline is added to the above decompression distillation kettle, and said aniline and the above ferric chloride solution are mixed under stirring, and the mass ratio of said aniline and ferric chloride is 1.0 to 1.5. ferric chloride in a mass ratio of 1.3:1; decompression distillation of said aniline and ferric chloride solution in said decompression distillation kettle under a pressure of -0.09 MPa to obtain a mixture; said decompression distillation starts at a temperature of 35 , said decompression distillation starts to produce fractions at 45 , and the decompression distillation ends at 72 ;
After the end of said distillation, said decompression distillation kettle is temperature-adjusted to 180 , within 5 hours to said decompression distillation kettle add nitrobenzene for condensation reaction, get aniline black; said nitrobenzene mass and the mass ratio of the above aniline is 1:4.