A method for extracting citric acid from a fermentation broth containing Acido Citrico, comprising the steps of:
(1) get 100kg of fermented liquid containing citric acid, be heated to 85 ℃, separate with decanter separator, obtain the clear liquid 95.0kg (acidity is 14.5wt%) containing citric acid;
(2) The citric acid-containing supernatant obtained in step (1) is successively 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) of production) and anion exchange resin column (D318 produced by Jiangsu Su Qing Water Treatment Engineering Group Co., Ltd.), obtain the decolouring separation solution 105.5kg (acidity 12.86wt%) containing citric acid, light transmittance 35%, Ca2+ quality Content 40ppm, SO42-mass content 200ppm);
(3) the decolorization and separation solution containing citric acid that step (2) obtains is used compound extraction agent (trilaurylamine: n-octanol: No. 260 solvent oil volume ratio=4:2:4) by volume ratio (composite extraction Extraction agent and the volume ratio of the decolorization separation liquid containing citric acid) 1:1 at 35 ℃, no emulsification phenomenon occurred in the extraction process, the phase separation time was 0.6min, and 118.8kg of the extraction load phase containing citric acid was obtained (acidity 11.25wt%) and raffinate phase;
(4) The citric acid-containing extraction load phase obtained in step (3) is washed with soft water at a volume ratio (volume ratio of the citric acid-containing extraction load phase to soft water) 25:1 at 35°C to obtain a citric acid-containing 118.0kg (acidity 10.98wt%) of the washing extraction load phase, washing solution 5.552kg (acidity 7.36wt%), and the washing solution can return to step (3) to mix and extract again with the decolorization and separation solution containing citric acid;
The washing and extraction load phase containing citric acid was back-extracted at 85°C with soft water in a volume ratio (volume ratio of the washing extraction load phase containing Acido Citrico to soft water) at 85°C to obtain 71.9kg of citric acid-containing back-extraction solution (acidity 17.66wt%), back-extraction solvent phase 105.1kg (acidity 0.246wt%), back-extraction solvent phase chromaticity value is 200Hazen;
(5) The citric acid-containing stripping solution 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 backextraction decolorization with an easy charcoal multiple of 2.2 When the back-extraction and decolorization liquid is concentrated at 75°C until the concentration of citric acid is 80wt%, the cooling crystallization begins, the cooling rate is controlled to be 2°C/h, the temperature is lowered to 16°C and centrifuged, and the wet crystals are dried at 65°C to obtain citric 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 clear liquid, 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 residual citric acid fermentation supernatant, the temperature of the washing water was 80°C, and the amount of washing water was 1 liter; 613.36 grams were obtained Calcium hydrogen citrate, the mixed solution that obtains the first liquid phase and washing liquid is totally 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 content is 380 grams per liter);
(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%.
Yield of citric acid (%)=amount of Acido Citrico obtained by acid hydrolysis×100%/content of citric acid in citric acid fermentation broth.