A waste liquid treatment method for producing DL-Methionine Powder, comprising the following steps:
S1, the saponified solution is separated by a cation exchange resin to obtain a sodium sulfate mother liquor, adding a flocculant and a coagulant aid to the sodium sulfate mother liquor, adding alkali to adjust the pH value of the solution, and filtering after fully mixing to obtain a filtrate;
S2, adding an acidic solution to the filtrate for acidification, the acidified solution is concentrated and then hot filtered for solid-liquid separation to obtain sodium sulfate solid and sodium sulfate filtrate;
S3, the sodium sulfate solid is washed with desalinated water to obtain the sodium sulfate product. When the methionine content in the sodium sulfate filtrate is ≤ 1%, return to step S1 and mix with the sodium sulfate mother liquor. When the methionine content in the sodium sulfate filtrate is ≥ 1%. , enter the methionine extraction process;
S4, mixing the electrodialysis concentrated water and the reverse osmosis concentrated water, adjusting the pH and concentrating, cooling and crystallizing, and separating to obtain methionine and methionine filtrate;
S5, after merging the sodium sulfate filtrate in S2 and the methionine filtrate in S4, separate them into methionine solution and sodium sulfate solution through chromatography, return the sodium sulfate solution to S1 after concentration and removal of impurities, and merge it with the sodium sulfate mother liquor, and perform S1- S4;
S6, after mixing the methionine in S4, the methionine solution in S5 and the saponification solution in S1, stripping and deamination and promoting the decomposition of methionine intermediates into methionine;
S7, the distilled water of S2, S4 and S5 is combined and absorbed by anion exchange resin to obtain desalted water.