High-temperature cooking, processing and softening method for lactic acid extraction

Abstract

The invention relates to the technical field of softening methods, in particular to a high-temperature cooking, processing and softening method for lactic acid extraction. The preparation method comprises the following steps: step 1, preparing raw materials; step 2, crushing the raw materials; step 3, mixing; step 4, cooking at a high temperature, step 5, filtering, step 6, cooling, step 7, concentrating, step 8, crystallizing, step 9, separating, step 10, drying, and step 11, screening and packaging. According to the method, the heavy-phase lactic acid is crushed into small particle size through the crushing and sieving machine, the contact area of the raw material and the solvent is increased, mass transfer and heat transfer in the subsequent mixing and cooking process are facilitated, the extraction efficiency is improved, interaction between the lactic acid and the solvent can be accelerated through high-temperature cooking, and the lactic acid is more easily released from the raw material; and in the cooking process, the mixture is ensured to be uniformly heated through stirring operation, lactic acid decomposition or quality reduction possibly caused by local overheating is prevented, and the stability and quality of the product are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of softening methods, in particular to a high-temperature cooking and softening method for lactic acid extraction. Background Art

[0002] Lactic acid extraction methods mainly include fermentation, synthesis, molecular distillation, membrane separation, adsorption, chromatographic separation technology, etc. Molecular distillation can simplify the lactic acid extraction steps and is suitable for fermentation broth with higher lactic acid purity, but the equipment investment is high and only deep processing of lactic acid products can be carried out.

[0003] Some traditional extraction methods, such as using calcium hydroxide to precipitate calcium lactate, have a large proportion of production costs in the separation and final purification stages, reaching 50%. This is mainly because the process consumes a large amount of slaked lime and sulfuric acid and produces calcium sulfate solid waste, which increases the cost of raw materials and waste treatment. The current method does not soften the raw materials through high-temperature cooking, and cannot make lactic acid more easily released from the raw materials, further reducing the extraction rate of lactic acid.

[0004] Therefore, in order to address the problem that the above-mentioned traditional lactic acid extraction method does not soften the lactic acid by high-temperature cooking to make it easier to release and extract the lactic acid from the raw material, a high-temperature cooking processing and softening method for lactic acid extraction can be designed. High-temperature cooking can accelerate the interaction between lactic acid and the solvent, making it easier to release lactic acid from the raw material, thereby further improving the extraction efficiency. Summary of the invention

[0005] In order to overcome the problem that the traditional lactic acid extraction method does not soften the raw materials through high temperature cooking to make lactic acid easier to release and extract.

[0006] The technical solution of the present invention is: a high temperature cooking and softening method for lactic acid extraction, and the preparation steps are as follows;

[0007] Step 1: Prepare the ingredients

[0008] Use an electronic scale to accurately weigh 1,100 kg of high-quality heavy-phase lactic acid as raw material, which is stored in a dry, cool, well-ventilated environment to avoid moisture, heat and pollution;

[0009] Step 2: Crushing raw materials

[0010] The heavy phase lactic acid is put into a crushing and screening machine for crushing, the aperture of the screen is between 0.6 mm and 3.5 mm, and the particle size range after crushing is between 50 microns and 2 mm;

[0011] Step 3: Mixing

[0012] According to the process requirements, a suitable solvent is selected and put into the mixer together with the heavy phase lactic acid for mixing and stirring until the heavy phase lactic acid and the solvent are evenly mixed without agglomeration;

[0013] Step 4: High temperature steaming

[0014] First, heat the cooking equipment to the preheating temperature and keep it for a period of time to ensure that the temperature inside the equipment is uniform, and then transport the above mixed raw materials to the cooking equipment. During the cooking process, turn on the stirrer to stir the mixture to ensure that the mixture is heated evenly and prevent local overheating;

[0015] Step 5: Filter

[0016] After the high-temperature cooking is completed, it is poured into a filtering device for filtering, and the filter pore size is between 9 microns and 100 microns;

[0017] Step 6: Cooling

[0018] The filtrate after the filtration is put into a cooler, the cooling temperature is between 10°C and 3°C, the cooling rate is between 5°C and 10°C per hour, and the cooler can be a plate cooler or a shell and tube cooler;

[0019] Step 7: Concentrate

[0020] The cooled filtrate is transported to a vacuum concentration device, and the water in the filtrate is evaporated by heating under reduced pressure to concentrate the lactic acid solution;

[0021] Step 8: Crystallization

[0022] Cooling the concentrated lactic acid solution to an appropriate temperature to allow the lactic acid to gradually crystallize and precipitate, thereby obtaining uniform and high-quality lactic acid crystals;

[0023] Step 9: Separation

[0024] The crystallized mixture is sent to a centrifuge, and the centrifugal force generated by high-speed rotation separates the lactic acid crystals from the mother liquor;

[0025] Step 10: Drying

[0026] The lactic acid crystals after centrifugal separation are sent to a dryer for drying at an appropriate temperature;

[0027] Step 11: Screening and packaging

[0028] The dried lactic acid crystals are screened using a vibrating screen or an airflow screen to remove particles that do not meet the requirements. The lactic acid that meets the requirements is between 980-1000 kg, and then packaged in a packaging machine according to certain specifications.

[0029] Preferably, the method uses a crushing and screening machine to crush the heavy phase lactic acid into smaller particles, thereby increasing the contact area between the raw material and the solvent, which is beneficial to mass transfer and heat transfer in the subsequent mixing and cooking process, thereby improving the extraction efficiency. High-temperature cooking can accelerate the interaction between lactic acid and the solvent, making it easier for lactic acid to be released from the raw material, further improving the extraction efficiency. During the cooking process, stirring is performed to ensure that the mixture is heated evenly, thereby preventing the decomposition or quality degradation of lactic acid that may be caused by local overheating, thereby ensuring the stability and quality of the product. A filter device with a pore size between 9 microns and 100 microns is used for filtration treatment, which effectively removes impurities and suspended matter in the solution and improves the purity of the product. During the cooling and drying process, the temperature and time range are precisely controlled to avoid the decomposition or discoloration of lactic acid, thereby ensuring the thermal stability and color stability of the product. The concentration operation is performed under reduced pressure conditions to reduce the boiling point of water, thereby reducing energy consumption and improving the concentration efficiency. During the entire process, reduced pressure concentration and precisely controlled cooling and drying technology are used to reduce the energy consumption of the entire process.

[0030] Preferably, the rotation speed of the crushing and screening machine in step 2 is between 1800r / min and 3000r / min.

[0031] Preferably, the solvent in step three can be water or ethanol, the ratio of water as solvent to heavy phase lactic acid is 6-8:1, the ratio of ethanol as solvent to heavy phase lactic acid is 3-4:1, and the mixing time is 8-25 minutes.

[0032] Preferably, the preheating temperature in step 4 is between 80°C and 90°C, the temperature range during the cooking process is between 90°C and 120°C, and the cooking time is between 30 minutes and 2 hours.

[0033] Preferably, the filtering equipment in step five can be any one of a plate and frame filter press, a vacuum drum filter or a centrifugal filter.

[0034] Preferably, the reduced pressure concentration equipment in step seven can be a vacuum evaporator or a thin film evaporator.

[0035] Preferably, the equipment used in step eight is a crystallization kettle and a refrigerator, the cooling rate is between 8 degrees and 12 degrees per hour, and the cooling temperature is between 10°C and 0°C.

[0036] Preferably, the drying temperature in step 10 is between 40° C. and 60° C., and the drying time is between 7 hours and 13 hours to avoid lactic acid decomposition or discoloration.

[0037] Beneficial effects of the present invention:

[0038] 1. The method crushes the heavy phase lactic acid to a smaller particle size by a crushing and screening machine, thereby increasing the contact area between the raw material and the solvent, which is beneficial to the mass transfer and heat transfer in the subsequent mixing and cooking process, thereby improving the extraction efficiency. High-temperature cooking can accelerate the interaction between lactic acid and the solvent, making it easier for lactic acid to be released from the raw material, further improving the extraction efficiency. During the cooking process, the stirring operation ensures that the mixture is heated evenly, preventing the decomposition or quality degradation of lactic acid that may be caused by local overheating, thereby ensuring the stability and quality of the product. The filtration equipment with a pore size between 9 microns and 100 microns is used for filtration treatment, effectively removing impurities and suspended matter in the solution, and improving the purity of the product. During the cooling and drying process, the temperature and time range are precisely controlled to avoid the decomposition or discoloration of lactic acid, ensuring the thermal stability and color stability of the product. The concentration operation is carried out under reduced pressure conditions, which reduces the boiling point of water, thereby reducing energy consumption and improving the concentration efficiency. In the entire process, the reduced pressure concentration and precisely controlled cooling and drying technology are used to reduce the energy consumption of the entire process. The method can realize the continuous production of lactic acid, reduce the manual operation links, and improve the production efficiency and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Shown is a flow chart of the high temperature cooking and softening method for lactic acid extraction of the present invention. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0041] See also Figure 1 , the present invention provides an embodiment: a high temperature cooking and softening method for lactic acid extraction, the preparation steps of which are as follows;

[0042] Step 1: Prepare the ingredients

[0043] Use an electronic scale to accurately weigh 1,100 kg of high-quality heavy-phase lactic acid as raw material, which is stored in a dry, cool, well-ventilated environment to avoid moisture, heat and pollution;

[0044] Step 2: Crushing raw materials

[0045] The heavy phase lactic acid is put into a crushing and screening machine for crushing, the aperture of the screen is between 0.6 mm and 3.5 mm, and the particle size range after crushing is between 50 microns and 2 mm;

[0046] Step 3: Mixing

[0047] According to the process requirements, a suitable solvent is selected and put into the mixer together with the heavy phase lactic acid for mixing and stirring until the heavy phase lactic acid and the solvent are evenly mixed without agglomeration;

[0048] Step 4: High temperature steaming

[0049] First, heat the cooking equipment to the preheating temperature and keep it for a period of time to ensure that the temperature inside the equipment is uniform, and then transport the above mixed raw materials to the cooking equipment. During the cooking process, turn on the stirrer to stir the mixture to ensure that the mixture is heated evenly and prevent local overheating;

[0050] Step 5: Filter

[0051] After the high-temperature cooking is completed, it is poured into a filtering device for filtering, and the filter pore size is between 9 microns and 100 microns;

[0052] Step 6: Cooling

[0053] The filtrate after the filtration is put into a cooler, the cooling temperature is between 10°C and 3°C, the cooling rate is between 5°C and 10°C per hour, and the cooler can be a plate cooler or a shell and tube cooler;

[0054] Step 7: Concentrate

[0055] The cooled filtrate is transported to a vacuum concentration device, and the water in the filtrate is evaporated by heating under reduced pressure to concentrate the lactic acid solution;

[0056] Step 8: Crystallization

[0057] Cooling the concentrated lactic acid solution to an appropriate temperature to allow the lactic acid to gradually crystallize and precipitate, thereby obtaining uniform and high-quality lactic acid crystals;

[0058] Step 9: Separation

[0059] The crystallized mixture is sent to a centrifuge, and the centrifugal force generated by high-speed rotation separates the lactic acid crystals from the mother liquor;

[0060] Step 10: Drying

[0061] The lactic acid crystals after centrifugal separation are sent to a dryer for drying at an appropriate temperature;

[0062] Step 11: Screening and packaging

[0063] The dried lactic acid crystals are screened using a vibrating screen or an airflow screen to remove particles that do not meet the requirements. The lactic acid that meets the requirements is between 980-1000 kg, and then packaged in a packaging machine according to certain specifications.

[0064] Example 1

[0065] The present invention provides an embodiment: a high temperature cooking and softening method for lactic acid extraction, the preparation steps of which are as follows;

[0066] Step 1: Prepare the ingredients

[0067] Use an electronic scale to accurately weigh 1,100 kg of high-quality heavy-phase lactic acid as raw material, which is stored in a dry, cool, well-ventilated environment to avoid moisture, heat and pollution;

[0068] Step 2: Crushing raw materials

[0069] The heavy phase lactic acid is put into a crushing and screening machine for crushing, the aperture of the screen is between 0.6 mm and 3.5 mm, the particle size after crushing is between 50 microns and 2 mm, and the rotation speed of the crushing and screening machine is between 1800 r / min-3000 r / min;

[0070] Step 3: Mixing

[0071] According to the process requirements, a suitable solvent is selected and put into the mixer together with the heavy phase lactic acid for mixing and stirring until the heavy phase lactic acid and the solvent are evenly mixed without agglomeration. The solvent can be water or ethanol. The ratio of water as solvent to heavy phase lactic acid is 6:1, and the ratio of ethanol as solvent to heavy phase lactic acid is 3:1. The mixing time is 8-25 minutes.

[0072] Step 4: High temperature steaming

[0073] First, the cooking equipment is heated to the preheating temperature and maintained for a period of time to ensure that the temperature inside the equipment is uniform, and then the mixed raw materials are transported to the cooking equipment. During the cooking process, the stirrer is turned on to stir the mixture to ensure that the mixture is heated evenly and to prevent local overheating. The preheating temperature is 80°C-90°C, the temperature range during the cooking process is between 90°C-120°C, and the cooking time is between 30 minutes and 2 hours;

[0074] Step 5: Filter

[0075] After the high-temperature cooking is completed, the mixture is poured into a filtering device for filtering. The filter pore size is between 9 microns and 100 microns. The filtering device can be any one of a plate and frame filter press, a vacuum drum filter or a centrifugal filter.

[0076] Step 6: Cooling

[0077] The filtrate after the filtration is put into a cooler, the cooling temperature is between 10°C and 3°C, the cooling rate is between 5°C and 10°C per hour, and the cooler can be a plate cooler or a shell and tube cooler;

[0078] Step 7: Concentrate

[0079] The cooled filtrate is transported to a vacuum concentration device, and the water in the filtrate is evaporated by heating under reduced pressure to concentrate the lactic acid solution. The vacuum concentration device can be a vacuum evaporator or a thin film evaporator;

[0080] Step 8: Crystallization

[0081] The concentrated lactic acid solution is cooled to an appropriate temperature to allow lactic acid to gradually crystallize and precipitate, so as to obtain uniform and high-quality lactic acid crystals. The equipment used is a crystallization kettle and a refrigerator. The cooling rate is between 8 and 12 degrees per hour and the cooling temperature is between 10°C and 0°C.

[0082] Step 9: Separation

[0083] The crystallized mixture is sent to a centrifuge, and the centrifugal force generated by high-speed rotation separates the lactic acid crystals from the mother liquor;

[0084] Step 10: Drying

[0085] The lactic acid crystals after centrifugal separation are sent to a dryer for drying at an appropriate temperature, the drying temperature is between 40°C and 60°C, and the drying time is between 7 hours and 13 hours to avoid decomposition or discoloration of the lactic acid;

[0086] Step 11: Screening and packaging

[0087] Use a vibrating screen or airflow screen to screen the dried lactic acid crystals to remove particles that do not meet the requirements. The lactic acid that meets the requirements is 980 kg, and then a packaging machine is used to package it according to certain specifications.

[0088] Example 2

[0089] The present invention provides an embodiment: a high temperature cooking and softening method for lactic acid extraction, the preparation steps of which are as follows;

[0090] Step 1: Prepare the ingredients

[0091] Use an electronic scale to accurately weigh 1,100 kg of high-quality heavy-phase lactic acid as raw material, which is stored in a dry, cool, well-ventilated environment to avoid moisture, heat and pollution;

[0092] Step 2: Crushing raw materials

[0093] The heavy phase lactic acid is put into a crushing and screening machine for crushing, the aperture of the screen is between 0.6 mm and 3.5 mm, the particle size after crushing is between 50 microns and 2 mm, and the rotation speed of the crushing and screening machine is between 1800 r / min-3000 r / min;

[0094] Step 3: Mixing

[0095] According to the process requirements, a suitable solvent is selected and put into the mixer together with the heavy phase lactic acid for mixing and stirring until the heavy phase lactic acid and the solvent are evenly mixed without agglomeration. The solvent can be water or ethanol. The ratio of water as solvent to heavy phase lactic acid is 7:1, and the ratio of ethanol as solvent to heavy phase lactic acid is 3.5:1. The mixing time is 8-25 minutes.

[0096] Step 4: High temperature steaming

[0097] First, the cooking equipment is heated to the preheating temperature and maintained for a period of time to ensure that the temperature inside the equipment is uniform, and then the mixed raw materials are transported to the cooking equipment. During the cooking process, the stirrer is turned on to stir the mixture to ensure that the mixture is heated evenly and to prevent local overheating. The preheating temperature is 80°C-90°C, the temperature range during the cooking process is between 90°C-120°C, and the cooking time is between 30 minutes and 2 hours;

[0098] Step 5: Filter

[0099] After the high-temperature cooking is completed, the mixture is poured into a filtering device for filtering. The filter pore size is between 9 microns and 100 microns. The filtering device can be any one of a plate and frame filter press, a vacuum drum filter or a centrifugal filter.

[0100] Step 6: Cooling

[0101] The filtrate after the filtration is put into a cooler, the cooling temperature is between 10°C and 3°C, the cooling rate is between 5°C and 10°C per hour, and the cooler can be a plate cooler or a shell and tube cooler;

[0102] Step 7: Concentrate

[0103] The cooled filtrate is transported to a vacuum concentration device, and the water in the filtrate is evaporated by heating under reduced pressure to concentrate the lactic acid solution. The vacuum concentration device can be a vacuum evaporator or a thin film evaporator;

[0104] Step 8: Crystallization

[0105] The concentrated lactic acid solution is cooled to an appropriate temperature to allow lactic acid to gradually crystallize and precipitate, so as to obtain uniform and high-quality lactic acid crystals. The equipment used is a crystallization kettle and a refrigerator. The cooling rate is between 8 and 12 degrees per hour and the cooling temperature is between 10°C and 0°C.

[0106] Step 9: Separation

[0107] The crystallized mixture is sent to a centrifuge, and the centrifugal force generated by high-speed rotation separates the lactic acid crystals from the mother liquor;

[0108] Step 10: Drying

[0109] The lactic acid crystals after centrifugal separation are sent to a dryer for drying at an appropriate temperature, the drying temperature is between 40°C and 60°C, and the drying time is between 7 hours and 13 hours to avoid decomposition or discoloration of the lactic acid;

[0110] Step 11: Screening and packaging

[0111] Use a vibrating screen or airflow screen to screen the dried lactic acid crystals to remove particles that do not meet the requirements. The lactic acid that meets the requirements is 990 kg, and then a packaging machine is used to package it according to certain specifications.

[0112] Example 3

[0113] The present invention provides an embodiment: a high temperature cooking and softening method for lactic acid extraction, the preparation steps of which are as follows;

[0114] Step 1: Prepare the ingredients

[0115] Use an electronic scale to accurately weigh 1,100 kg of high-quality heavy-phase lactic acid as raw material, which is stored in a dry, cool, well-ventilated environment to avoid moisture, heat and pollution;

[0116] Step 2: Crushing raw materials

[0117] The heavy phase lactic acid is put into a crushing and screening machine for crushing, the aperture of the screen is between 0.6 mm and 3.5 mm, the particle size after crushing is between 50 microns and 2 mm, and the rotation speed of the crushing and screening machine is between 1800 r / min-3000 r / min;

[0118] Step 3: Mixing

[0119] According to the process requirements, a suitable solvent is selected and put into the mixer together with the heavy phase lactic acid for mixing and stirring until the heavy phase lactic acid and the solvent are evenly mixed without agglomeration. The solvent can be water or ethanol. The ratio of water as solvent to heavy phase lactic acid is 8:1, and the ratio of ethanol as solvent to heavy phase lactic acid is 4:1. The mixing time is 8-25 minutes.

[0120] Step 4: High temperature steaming

[0121] First, the cooking equipment is heated to the preheating temperature and maintained for a period of time to ensure that the temperature inside the equipment is uniform, and then the mixed raw materials are transported to the cooking equipment. During the cooking process, the stirrer is turned on to stir the mixture to ensure that the mixture is heated evenly and to prevent local overheating. The preheating temperature is 80°C-90°C, the temperature range during the cooking process is between 90°C-120°C, and the cooking time is between 30 minutes and 2 hours;

[0122] Step 5: Filter

[0123] After the high-temperature cooking is completed, the mixture is poured into a filtering device for filtering. The filter pore size is between 9 microns and 100 microns. The filtering device can be any one of a plate and frame filter press, a vacuum drum filter or a centrifugal filter.

[0124] Step 6: Cooling

[0125] The filtrate after the filtration is put into a cooler, the cooling temperature is between 10°C and 3°C, the cooling rate is between 5°C and 10°C per hour, and the cooler can be a plate cooler or a shell and tube cooler;

[0126] Step 7: Concentrate

[0127] The cooled filtrate is transported to a vacuum concentration device, and the water in the filtrate is evaporated by heating under reduced pressure to concentrate the lactic acid solution. The vacuum concentration device can be a vacuum evaporator or a thin film evaporator;

[0128] Step 8: Crystallization

[0129] The concentrated lactic acid solution is cooled to an appropriate temperature to allow lactic acid to gradually crystallize and precipitate, so as to obtain uniform and high-quality lactic acid crystals. The equipment used is a crystallization kettle and a refrigerator. The cooling rate is between 8 and 12 degrees per hour and the cooling temperature is between 10°C and 0°C.

[0130] Step 9: Separation

[0131] The crystallized mixture is sent to a centrifuge, and the centrifugal force generated by high-speed rotation separates the lactic acid crystals from the mother liquor;

[0132] Step 10: Drying

[0133] The lactic acid crystals after centrifugal separation are sent to a dryer for drying at an appropriate temperature, the drying temperature is between 40°C and 60°C, and the drying time is between 7 hours and 13 hours to avoid decomposition or discoloration of the lactic acid;

[0134] Step 11: Screening and packaging

[0135] The dried lactic acid crystals are screened using a vibrating screen or an airflow screen to remove particles that do not meet the requirements. The lactic acid that meets the requirements is between 1,000 kg, and then packaged in a packaging machine according to certain specifications.

[0136] Through the above steps, the method crushes the heavy phase lactic acid into smaller particles by a crushing and screening machine, thereby increasing the contact area between the raw material and the solvent, which is beneficial to the mass transfer and heat transfer in the subsequent mixing and cooking process, thereby improving the extraction efficiency. High-temperature cooking can accelerate the interaction between lactic acid and the solvent, making it easier for lactic acid to be released from the raw material, further improving the extraction efficiency. During the cooking process, the stirring operation is used to ensure that the mixture is heated evenly, thereby preventing the decomposition or quality degradation of lactic acid that may be caused by local overheating, thereby ensuring the stability and quality of the product. The filtration equipment with a pore size between 9 microns and 100 microns is used for filtration treatment, effectively removing impurities and suspended matter in the solution, and improving the purity of the product. During the cooling and drying process, the temperature and time range are precisely controlled to avoid the decomposition or discoloration of lactic acid, thereby ensuring the thermal stability and color stability of the product. The concentration operation is carried out under reduced pressure conditions, which reduces the boiling point of water, thereby reducing energy consumption and improving the concentration efficiency, so as to solve the problem that the traditional lactic acid extraction method does not soften the lactic acid by high-temperature cooking to make it easier to release and extract lactic acid from the raw material.

[0137] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of those skilled in the art without departing from the spirit of the present invention.

Claims

1. A high temperature cooking and softening method for extracting lactic acid, characterized in that: The preparation steps are as follows: Step 1: Prepare the ingredients Use an electronic scale to accurately weigh 1,100 kg of high-quality heavy-phase lactic acid as raw material, which is stored in a dry, cool, well-ventilated environment to avoid moisture, heat and pollution; Step 2: Crushing raw materials The heavy phase lactic acid is put into a crushing and screening machine for crushing, the aperture of the screen is between 0.6 mm and 3.5 mm, and the particle size range after crushing is between 50 microns and 2 mm; Step 3: Mixing According to the process requirements, a suitable solvent is selected and put into the mixer together with the heavy phase lactic acid for mixing and stirring until the heavy phase lactic acid and the solvent are evenly mixed without agglomeration; Step 4: High temperature steaming First, heat the cooking equipment to the preheating temperature and keep it for a period of time to ensure that the temperature inside the equipment is uniform, and then transport the above mixed raw materials to the cooking equipment. During the cooking process, turn on the stirrer to stir the mixture to ensure that the mixture is heated evenly and prevent local overheating; Step 5: Filter After the high-temperature cooking is completed, it is poured into a filtering device for filtering, and the filter pore size is between 9 microns and 100 microns; Step 6: Cooling The filtrate after the filtration is put into a cooler, the cooling temperature is between 10°C and 3°C, the cooling rate is between 5°C and 10°C per hour, and the cooler can be a plate cooler or a shell and tube cooler; Step 7: Concentrate The cooled filtrate is transported to a vacuum concentration device, and the water in the filtrate is evaporated by heating under reduced pressure to concentrate the lactic acid solution; Step 8: Crystallization Cooling the concentrated lactic acid solution to an appropriate temperature to allow the lactic acid to gradually crystallize and precipitate, thereby obtaining uniform and high-quality lactic acid crystals; Step 9: Separation The crystallized mixture is sent to a centrifuge, and the centrifugal force generated by high-speed rotation separates the lactic acid crystals from the mother liquor; Step 10: Drying The lactic acid crystals after centrifugal separation are sent to a dryer for drying at an appropriate temperature; Step 11: Screening and packaging The dried lactic acid crystals are screened using a vibrating screen or an airflow screen to remove particles that do not meet the requirements. The lactic acid that meets the requirements is between 980-1000 kg, and then packaged in a packaging machine according to certain specifications.

2. The high temperature cooking and softening method for extracting lactic acid according to claim 1, characterized in that: In step 2, the rotation speed of the crushing and screening machine is between 1800r / min and 3000r / min.

3. The high temperature cooking and softening method for extracting lactic acid according to claim 1, characterized in that: In step 3, the solvent can be water or ethanol. The ratio of water as solvent to heavy phase lactic acid is 6 to 8:1, and the ratio of ethanol as solvent to heavy phase lactic acid is 3 to 4:

1. The mixing time is 8 to 25 minutes.

4. The high temperature cooking and softening method for extracting lactic acid according to claim 1, characterized in that: The preheating temperature in step 4 is between 80°C and 90°C, the temperature range during the cooking process is between 90°C and 120°C, and the cooking time is between 30 minutes and 2 hours.

5. The high temperature cooking and softening method for extracting lactic acid according to claim 1, characterized in that: The filtering equipment in step five can specifically be any one of a plate and frame filter press, a vacuum drum filter or a centrifugal filter.

6. The high temperature cooking and softening method for extracting lactic acid according to claim 1, characterized in that: The reduced pressure concentration equipment in step seven may specifically be a vacuum evaporator or a thin film evaporator.

7. The high temperature cooking and softening method for extracting lactic acid according to claim 1, characterized in that: The equipment used in step eight is a crystallization kettle and a refrigerator, the cooling rate is between 8 degrees and 12 degrees per hour, and the cooling temperature is between 10°C and 0°C.

8. The high temperature cooking and softening method for extracting lactic acid according to claim 1, characterized in that: The drying temperature in step 10 is between 40° C. and 60° C., and the drying time is between 7 hours and 13 hours to avoid lactic acid decomposition or discoloration.

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