A method for extracting citric acid from a fermented liquid containing Citric Acid Powder, comprising the steps of:
(1) Get 100kg of fermented liquid containing Citric Acid Powder, heat it to 85°C, and separate it with a decanter separator to obtain 95.0kg of clear liquid containing citric acid (acidity is 14.5wt%);
(2) The supernatant liquid containing Citric Acid Powder obtained in step (1) is sequentially passed through a decolorization column (GH-15 granular activated carbon produced by Guanghua Jingke Environmental Protection Technology Co., Ltd.), a cation exchange resin column (Jiangsu Suqing Water Treatment Engineering Group Co., Ltd. 001 × 7) produced by the company) and anion exchange resin column (D318 produced by Jiangsu Suqing Water Treatment Engineering Group Co., Ltd.), to obtain 105.5kg of decolorization and separation solution containing citric acid (acidity 12.86wt%, light transmittance 35%, Ca2+ Mass content 40ppm, SO42-mass content 200ppm);
(3) the decolorization and separation solution containing Citric Acid Powder that step (2) obtains is used compound extractant (trilaurylamine: n-octanol: No. 260 solvent oil volume ratio=4:2:4) by volume ratio (composite The volume ratio of extractant to the decolorization separation solution containing citric acid) was extracted at 35°C at 1:1, no emulsification occurred during the extraction process, and the phase separation time was 0.6min to obtain 118.8kg of the extraction load phase containing citric acid ( Acidity 11.25wt%) and raffinate phase;
(4) Wash the extraction loading phase containing Citric Acid Powder obtained in step (3) with soft water at a volume ratio (volume ratio of the extraction loading phase containing citric acid to soft water) 25:1 at 35°C to obtain Acid washing and extracting load phase 118.0kg (acidity 10.98wt%), washing solution 5.552kg (acidity 7.36wt%), washing solution can return to step (3) and contain citric acid decolorization separation solution to mix and extract again;
The washing extraction load phase containing Citric Acid Powder was back-extracted at 85°C with soft water in a volume ratio (the volume ratio of the washing extraction load phase containing citric acid to soft water) at 85°C to obtain a citric acid-containing back extraction solution 71.9 kg (acidity 17.66wt%), back-extraction solvent phase 105.1kg (acidity 0.246wt%), back-extraction solvent phase chromaticity value is 200Hazen;
(5) The back extraction solution containing Citric Acid Powder obtained in step (4) is decolorized (the charcoal trump card ZS-21 organic acid decolorization special carbon produced by Nanjing Zhengsen Environmental Protection Activated Carbon Co., Ltd.), to obtain a back extraction with an easy charcoal multiple of 2.2 Decolorization solution, back extraction and decolorization solution is concentrated at 75°C until the concentration of citric acid is 80wt%, then cooling crystallization is started, the cooling rate is controlled at 2°C/h, the temperature is lowered to 16°C and centrifuged, and the wet crystals are dried at 65°C to obtain lemon Acid finished product (citric acid content 99.75%, yield 92.18%).
(1) At 75°C, add calcium carbonate to 5 liters of citric acid fermentation serum, and when the pH value of the control end point is 2.95, stop adding calcium carbonate, the reaction time is 5 hours, then carry out solid-liquid separation, filter and separate to obtain Solid phase calcium hydrogen citrate and 4.54 liters of the first liquid phase; the calcium hydrogen citrate was washed with water to remove the residual Citric Acid Powder fermentation supernatant, the temperature of the washing water was 80°C, and the amount of washing water was 1 liter; 613.36 Gram calcium hydrogen citrate, obtain the mixed solution of the first liquid phase and washing liquid altogether 5.54 liters;
(2) At 85°C, mix the washed calcium hydrogen citrate obtained in step (1) with 261.34 grams of concentrated sulfuric acid (the concentration of sulfuric acid is 98% by weight), control the pH value to 1.7, react for 50 minutes, and obtain 1.35 liters of citric acid solution (Citric Acid Powder content is 380 g/L);
(3) Calcium carbonate is joined in the first liquid phase that 5.54 liters of step (1) obtains and the mixed solution of washing liquid, when the pH value of control end point is 5, stop adding calcium carbonate, the reaction times is 45 minutes, carry out solidification then Liquid separation obtains 29.3 grams of calcium citrate and the second liquid phase, and the second liquid phase is carried out to waste water treatment;
(4) the citric acid obtained by the acid hydrolysis of the solid-phase calcium hydrogen citrate obtained in step (1) is 512.02 grams; the mixed solution of the first liquid phase and washing liquid obtained in step (1) is contacted with calcium carbonate to obtain Calcium citrate was mixed with 17.3 grams of concentrated sulfuric acid (the concentration of sulfuric acid was 98% by weight), the pH value was controlled to be 1.7, and the reaction was carried out for 50 minutes. The acid hydrolysis obtained 22.59 grams of citric acid, and a total of 534.61 grams of citric acid was obtained. And according to the following formula, the yield of citric acid is 97.2%.
Citric acid yield (%)=the amount of citric acid obtained by acid hydrolysis×100%/the content of citric acid in the fermentation liquid of Citric Acid Powder.