A waste liquid treatment method for producing DL-Methionine Powder, comprising the following steps:
S1, the saponification solution is separated by cation exchange resin to obtain sodium sulfate mother liquor, flocculant and coagulant aid are added to the sodium sulfate mother liquor, alkali is added to adjust the pH value of the solution, and the solution is fully mixed and filtered to obtain a filtrate;
S2, in the filtrate, add acid solution for acidification, the acidified solution is concentrated and then hot filtered to carry out solid-liquid separation to obtain sodium sulfate solid and sodium sulfate filtrate;
S3, the sodium sulfate solid is washed with desalted water to obtain a sodium sulfate product, when the methionine content in the sodium sulfate filtrate is less than or equal to 1%, return to step S1, and mix with the sodium sulfate mother liquor, when the sodium sulfate filtrate The methionine content is more than or equal to 1% , enter the methionine extraction process;
S4, mixing electrodialysis concentrated water and reverse osmosis concentrated water, adjusting pH and concentrating, cooling and crystallization, and separating to obtain methionine and methionine filtrate;
S5, after the sodium sulfate filtrate in S2 and the methionine filtrate in S4 are combined, separated into methionine solution and sodium sulfate solution by chromatography, return in S1 after the sodium sulfate solution is concentrated and removed impurities, merge with sodium sulfate mother liquor, and execute S1- S4;
S6, after mixing the methionine in S4, the methionine solution in S5 and the saponification solution in S1, stripping deamination and promoting the decomposition of methionine intermediate into methionine;
S7, the distilled water of S2, S4 and S5 is combined to obtain desalted water after adsorption by anion exchange resin.