CN103483184B - Method for producing anhydrous citric acid crystals - Google Patents
Method for producing anhydrous citric acid crystals Download PDFInfo
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- CN103483184B CN103483184B CN201310462436.8A CN201310462436A CN103483184B CN 103483184 B CN103483184 B CN 103483184B CN 201310462436 A CN201310462436 A CN 201310462436A CN 103483184 B CN103483184 B CN 103483184B
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- C07C51/42—Separation; Purification; Stabilisation; Use of additives
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Abstract
The invention discloses a method for producing anhydrous citric acid crystals. The method comprises the following steps: crystallizing a citric acid solution under the circulating stirring condition to obtain a crystal slurry solution; changing the initial temperature of the crystal slurry solution to repair crystals in the crystal slurry solution, and obtaining a solution containing the anhydrous citric acid crystals, wherein the process of changing the initial temperature of the crystal slurry solution comprises the following steps: (1) heating the crystal slurry solution to 2-20 DEG C after crystallization; (2) cooling the crystal slurry solution to 1-10 DEG C after crystallization; or (3) heating the crystal slurry solution to 2-20 DEG C at first after crystallization and then cooling the heated crystal slurry solution to 2-25 DEG C. Through the technical scheme, recesses in crystal surfaces can be effectively removed, and residues in mother liquid in the crystals are reduced, so that the content of water in the crystals is reduced; moreover, anhydrous citric acid molecules on the crystal surfaces are rearranged in a repair process, so that the quality is effectively improved and readily carbonizable substances are reduced.
Description
Technical field
The present invention relates to a kind of production method of anhydrous citric acid crystal.
Background technology
The continuous production method of current industrial Citric Acid, usp, Anhydrous Powder comprises: first citric acid fermentation broth is obtained citric acid clear liquid through solid-liquid separation, then citric acid clear liquid is extracted through hydrogen calcium method or calcium salt method, acidolysis also decolouring obtains the citric acid solution of purification, again by concentrated for the citric acid solution heating of purifying, the above-mentioned citric acid solution concentrated is injected crystallizer continuously, citric acid concentrated solution is made to reach hypersaturated state by evaporation, solution nature graining, then the evaporation limit crystallization of citric acid solution limit is added on limit, when the gross weight that solids content (anhydrous citric acid crystal) reaches the mixture of citric acid solution and solid to a certain degree time, start the magma of continuous and quantitative discharge containing anhydrous citric acid crystal, and the continuous operation of keeping system.Again the magma of advantages of good crystallization is carried out centrifugation to obtain Citric Acid, usp, Anhydrous Powder and to wet crystal and crystalline mother solution, and wet crystal is dried obtain dry anhydrous citric acid crystal.
But adopt the shortcoming of aforesaid method to be: the Citric Acid, usp, Anhydrous Powder of the gained crystal entrainment mother liquor that wets is many, and the dry crystal mass obtained after oven dry is poor, readily carbonizable substance and moisture content higher.
Summary of the invention
The object of the invention is to overcome prior art, to obtain the Citric Acid, usp, Anhydrous Powder crystal entrainment mother liquor that wets more, dry crystal mass is poor, readily carbonizable substance and the higher defect of moisture content, there is provided a kind of Citric Acid, usp, Anhydrous Powder obtained crystal entrainment mother liquor that wets few, dry crystal mass is good, the production method of readily carbonizable substance and the lower anhydrous citric acid crystal of moisture content.
The present inventor finds, the Citric Acid, usp, Anhydrous Powder that prior art the obtains crystal entrainment mother liquor that wets is more, dry crystal mass is poor, readily carbonizable substance and the higher reason of moisture content are: in the process of Citric Acid, usp, Anhydrous Powder evaporative crystallization, must constantly it just can be made to mix citric acid solution circulation, but the fast rotational of the recycle pump blade of crystal system (general rotating speed is 650-800rpm) can make the Citric Acid, usp, Anhydrous Powder of precipitation cannot by normal sequential aggradation to plane of crystal, thus cause plane of crystal to occur depression, depressed area can make mother liquor remain in a large number.Therefore, make crystal moisture content higher, easily lump; And the anhydrous citric acid crystal obtained not according to normal crystallization order of crystallization is second-rate, and readily carbonizable substance is higher.
The present inventor finds unexpectedly, by the magma obtained after citric acid solution condensing crystal with 1) the magma intensification 2-20 DEG C that will obtain after crystallization; 2) the magma cooling 1-10 DEG C will obtained after crystallization; 3) the magma intensification 2-20 DEG C first will obtained after crystallization, then any one method in magma cooling 2-25 DEG C after heating up is carried out repairing effectively can reduce the residual of mother liquor in crystal, make its moisture content obtain reduction; And the crystal arrangement finally obtained is comparatively regular, its quality is obtained and effectively improves, and reduce readily carbonizable substance.
Based on above discovery, the invention provides a kind of production method of anhydrous citric acid crystal, the method comprises, under the condition of circulation stirring, citric acid solution is carried out crystallization, obtains magma, wherein, the method also comprises the initial temperature of change magma to repair the crystal in magma, obtains the feed liquid containing anhydrous citric acid crystal; The method of described change magma initial temperature comprises:
1) the magma intensification 2-20 DEG C will obtained after crystallization,
2) the magma cooling 1-10 DEG C will obtained after crystallization, or
3) the magma intensification 2-20 DEG C first will obtained after crystallization, then by the magma cooling 2-25 DEG C after intensification.
Preferably, method 1) and 3) in, the speed magma obtained after crystallization heated up is 1-10 DEG C/h; Method 2) and 3) in, the speed of the magma obtained after crystallization being lowered the temperature or the magma after intensification being lowered the temperature is 1-8 DEG C/h.
Preferably, method 3) in, by lower at most than the initial temperature of magma 5 DEG C for the temperature of the magma obtained after the magma cooling after intensification.
Preferably, described reparation is carried out under the condition stirred, and the speed of described stirring is 20-30rpm.
Crystal in the magma obtained crystallization by technique scheme is repaired, and effectively can eliminate the depression of plane of crystal, thus can reduce the residual of mother liquor in crystal, reduces the moisture content in crystal.And in the process of repairing, the Citric Acid, usp, Anhydrous Powder molecule of plane of crystal is reset, and makes its quality obtain effective raising, and reduces readily carbonizable substance.And carry out the reparation of anhydrous citric acid crystal under above-mentioned preferred condition, make the residue of mother of anhydrous citric acid crystal reduce further, moisture content and the readily carbonizable substance of crystal reduce further, and crystal outward appearance is more regular.
Other features and advantages of the present invention are described in detail in embodiment part subsequently.
Accompanying drawing explanation
Accompanying drawing is used to provide a further understanding of the present invention, and forms a part for specification sheets, is used from explanation the present invention, but is not construed as limiting the invention with embodiment one below.In the accompanying drawings:
Fig. 1 is the MIcrosope image of the anhydrous citric acid crystal obtained according to the method for embodiment 1, and magnification is 60 times;
Fig. 2 is the MIcrosope image of the anhydrous citric acid crystal obtained according to the method for comparative example 1, and magnification is 60 times.
Embodiment
Below the specific embodiment of the present invention is described in detail.Should be understood that, embodiment described herein, only for instruction and explanation of the present invention, is not limited to the present invention.
The invention provides a kind of production method of anhydrous citric acid crystal, the method comprises, under the condition of circulation stirring, citric acid solution is carried out crystallization, obtain magma, wherein, the method also comprises the initial temperature of change magma to repair the crystal in magma, obtains the feed liquid containing anhydrous citric acid crystal; The method of described change magma initial temperature comprises:
1) the magma intensification 2-20 DEG C will obtained after crystallization,
2) the magma cooling 1-10 DEG C will obtained after crystallization, or
3) the magma intensification 2-20 DEG C first will obtained after crystallization, then by the magma cooling 2-25 DEG C after intensification.
Preferably, method 1) in, by the magma intensification 5-15 DEG C obtained after crystallization; Method 2) in, by the magma cooling 2-8 DEG C obtained after crystallization; Method 3) in, the magma intensification 5-15 DEG C first will obtained after crystallization, then by the magma cooling 5-20 DEG C after intensification.Effectively can repair the surface of crystal further.
According to the present invention, have no particular limits the time that crystal is repaired, those skilled in the art can adjust according to the reparation situation of reality.Preferably, consider repairing effect and repair time consumption, method 1) in repair time be 10-30 minute; Method 2) in repair time be 10-30 minute; Method 3) in, the repair time of temperature-rise period is 10-20 minute, then the repair time of temperature-fall period is 10-20 minute.
It should be noted that after all referring to change temperature to steady temperature above-mentioned repair time herein, and the time kept under this steady temperature.
Above-mentioned 3 kinds of the present invention change in the method for magma temperature, and the present inventor finds, to change, can improve the quality of final crystal product further by slowly heating up or lowering the temperature to the temperature of magma.Such as, in method 1) in, the speed of intensification can be 1-10 DEG C/h, is preferably 3-8 DEG C/h; Method 2) in, the speed of cooling can be 1-8 DEG C/h, is preferably 2-6 DEG C/h; Method 3) in, the heat-up rate first heated up can be 1-10 DEG C/h, is preferably 3-8 DEG C/h, then the speed of lowering the temperature can be 1-8 DEG C/h, is preferably 2-6 DEG C/h, and the quality of final gained crystal can improve further.And in method 3) in, the quality of crystal can be improved during lower at most than the initial temperature of magma 5 DEG C of the temperature of the magma preferably obtained after cooling further.
After magma heats up, the concave face of crystal can dissolve, then in the process of slow cooling, promote that the citric acid molecule on the anhydrous citric acid crystal surface of separating out is reset, and then the depression of plane of crystal can be eliminated, then by cooling, the citric acid molecule of dissolving is separated out under mild conditions again more regularly on the surface of already present crystal.Therefore, when taking into account crystal mass and percent crystallization in massecuite, the present invention preferably adopts method 3) change the initial temperature of magma to repair crystal.
In the present invention, the initial temperature of described magma refers to the temperature of the magma of gained during citric acid solution evaporative crystallization terminal, and under normal circumstances, the temperature of the magma obtained during evaporative crystallization terminal, also namely initial temperature is 50-70 DEG C.
The present inventor is surprised to find, be 1-8 DEG C/h in cooling rate, under being preferably the condition of 2-6 DEG C/h, the speed that the speed that Citric Acid, usp, Anhydrous Powder molecule is separated out and crystal growth also form more regular outward appearance can reach good coordination, thus it is more regular to make anhydrous citric acid crystal arrange, thus have good reparation to crystal, significantly reduce the probability of crystal entrainment mother liquor, the quality of the anhydrous citric acid crystal obtained can be promoted further.
In the present invention, the conventional cool-down method used in this area can be adopted to the method that citric acid magma is lowered the temperature, such as, heat-eliminating medium can be adopted to carry out the method for lowering the temperature.Heat-eliminating medium can be the various material that can realize cooling down effect well known by persons skilled in the art, such as water coolant or cooling air.The preferred heat-eliminating medium of the present invention is water coolant.
According to the present invention, in order to make anhydrous citric acid crystal more even dispersedly, thus make temperature variation in the process heated up and/or lower the temperature more consistent, and the Citric Acid, usp, Anhydrous Powder molecule of separating out can adhere to into crystalline substance faster, the process of described intensification or cooling is carried out under the condition stirred.The range of choices of the speed of described stirring is wider, only otherwise affect the precipitation of crystal and do not make crystal formation to cave in etc. affect the outward appearance of crystal.Preferably, the speed of described stirring is 20-30rpm, is more preferably 22-26rpm.
Well known to a person skilled in the art and be, by citric acid solution evaporative crystallization, and ensure that the temperature of citric acid concentrated solution is higher than 36.6 DEG C, what crystallization generated is anhydrous citric acid crystal.Wherein, described method of citric acid solution being carried out evaporative crystallization is conventionally known to one of skill in the art, such as, Citric Acid, usp, Anhydrous Powder generally adopts evaporative crystallization, first certain density citric acid feed liquid is evaporated, be evaporated to a certain degree natural graining, the magma after graining continues evaporation, stops crystallization when crystal growth is about 45-55 % by weight to crystalline content.
In the present invention, when repairing, the content of anhydrous citric acid crystal in magma is not specially required, but in order to improve the crystal yield of final gained, in preferred described magma, the content of anhydrous citric acid crystal is 45-55 % by weight.
Described citric acid solution can be the comparatively pure citric acid solution that the various solution (usual solvents is water) containing citric acid obtains through the various impurity of removing, in described citric acid solution, the content of citric acid can be chosen in a big way, from industrial production and economical point, in preferred described citric acid solution, the content of citric acid is 55-65 % by weight.Described citric acid solution can be the raw materials such as potato dry powder, Tapioca Starch, Semen Maydis powder, potato powder, starch and glucose mother liquid, the citric acid solution after the fermentation liquor press filtration of the fermentable such as aspergillus niger, neutralization, acidolysis, desolventing technology.
In the present invention, the method also comprises, the feed liquid obtained containing anhydrous citric acid crystal after reparation is carried out solid-liquid separation, and the method for described solid-liquid separation can adopt and well known to a person skilled in the art various method, the methods such as such as vacuum filtration, settlement separate and centrifugation.In the preferred situation of the present invention, adopt the method for centrifugation, the rotating speed of centrifugation can be 60-800rpm, concrete control rotating speed is as follows: when adding the magma after reparation in the rotary drum of whizzer, the rotating speed maintaining whizzer is 400-600rpm, and when not adding materials and only dewater, the rotating speed maintaining whizzer is 600-800rpm, during discharging, the rotating speed maintaining whizzer is 60-100rpm.
According to the present invention, after carrying out solid-liquid separation, gained Citric Acid, usp, Anhydrous Powder wets crystal can by obtaining anhydrous citric acid crystal product after dry removing free-water; Gained liquid can recycle, and is fully applied to make raw material.Method and the condition of described drying removing free-water can adopt various method known in the art and condition.Such as, dry mode can be the drying mode of the various routines such as forced air drying, vacuum-drying, fluidized drying, preferred fluidized-bed fluidized drying mode; Preferred drying temperature is: hot blast 25-35 DEG C, and cold wind is 5-20 DEG C, and time of drying is 10-30 minute.
Below will be described the present invention by embodiment.
In following examples and comparative example:
Employing GB1987-2007 national standard method measures the readily carbonizable substance in final gained anhydrous citric acid crystal;
In anhydrous citric acid crystal, moisture determination adopts full-automatic karl Fischer moisture titration (purchased from Mei Tele company, model: DL55) to measure;
The measuring method of anhydrous citric acid crystal content in magma: take 1kg Citric Acid, usp, Anhydrous Powder magma, after its centrifugation being dried, the amount of gained crystal and the ratio of 1kg magma are crystalline content;
The method of the magma after reparation being carried out to solid-liquid separation is: whizzer is purchased from Liaoyang You Xin pharmaceutical machine Science and Technology Ltd., model is PGZ1600, concrete control rotating speed is as follows: when adding the magma obtained after repairing in the rotary drum of whizzer, the rotating speed maintaining whizzer is 500rpm, when not adding materials and only dewater, the rotating speed maintaining whizzer is 800rpm, and during discharging, the rotating speed maintaining whizzer is 60rpm.
Embodiment 1
The present embodiment is for illustration of the production method of anhydrous citric acid crystal provided by the invention.
(1) evaporative crystallization of citric acid solution
By 10m
3citric acid content be 60 % by weight citric acid solution inject effective volume be 15m
3crystallisation vessel in carry out evaporative crystallization, input speed controls as charging 4m per hour
3, charging limit, limit is evaporated, and crystallization control temperature is 70 DEG C, and the stirring velocity of recycle pump is 750rpm.The time of crystallization control makes the content of anhydrous citric acid crystal in magma reach 55 % by weight.
(2) to the reparation of crystal in magma
The magma of gained in step (1) is injected in dashpot, under the condition that 22rpm stirs always, with the speed of 3 DEG C/h, the temperature of magma is risen to 75 DEG C, and maintain 20 minutes, obtain the feed liquid containing anhydrous citric acid crystal.Then with the speed of 2 DEG C/h, the feed liquid containing anhydrous citric acid crystal is lowered the temperature, be cooled to 70 DEG C and keep 10 minutes, start blowing.And solid-liquid separation is carried out to the magma after repairing and dry (hot blast 25 DEG C, cold wind 10 DEG C of dryings 30 minutes) obtain dry anhydrous citric acid crystal by centrifugal.After dry, the readily carbonizable substance of anhydrous citric acid crystal, moisture content and transmittance are in table 1.The microscope photograph of gained crystal as shown in Figure 1.
Embodiment 2
The present embodiment is for illustration of the production method of anhydrous citric acid crystal provided by the invention.
(1) evaporative crystallization of citric acid solution
By 9.2m
3citric acid content be 65 % by weight citric acid solution inject effective volume be 15m
3crystallisation vessel in carry out evaporative crystallization, input speed controls as charging 4.3m per hour
3, charging limit, limit is evaporated, and crystallization control temperature is 50 DEG C, and the stirring velocity of recycle pump is 800rpm.The time of crystallization control makes the content of anhydrous citric acid crystal in magma reach 45 % by weight.
(2) to the reparation of crystal in magma
The magma of gained in step (1) is injected in dashpot, under the condition that 26rpm stirs always, with the speed of 8 DEG C/h, the temperature of magma is risen to 65 DEG C, and maintain 10 minutes, obtain the feed liquid containing anhydrous citric acid crystal.Then with the speed of 6 DEG C/h, the feed liquid containing anhydrous citric acid crystal is lowered the temperature, and be cooled to 45 DEG C and maintain 20 minutes, start blowing.And obtain dry anhydrous citric acid crystal by carrying out solid-liquid separation also drying (hot blast 35 DEG C, 20 DEG C, cold wind, dry 20 minutes) to the magma after reparation.After dry, the readily carbonizable substance of anhydrous citric acid crystal, moisture content and transmittance are in table 1.The face shaping of gained crystal is similar to Example 1.
Embodiment 3
The present embodiment is for illustration of the production method of anhydrous citric acid crystal provided by the invention.
(1) evaporative crystallization of citric acid solution
By 11m
3citric acid content be 55 % by weight citric acid solution injected slurry volume be 15m
3crystallisation vessel in carry out evaporative crystallization, input speed controls as charging 4.1m per hour
3, charging limit, limit is evaporated, and crystallization control temperature is 58 DEG C, and the stirring velocity of recycle pump is 650rpm.The time of crystallization control makes the content of anhydrous citric acid crystal in magma reach 50 % by weight.
(2) to the reparation of crystal in magma
The magma of gained in step (1) is injected in dashpot, under the condition that 24rpm stirs always, with the speed of 6 DEG C/h, the temperature of magma is risen to 68 DEG C, and maintain 15 minutes, obtain the feed liquid containing anhydrous citric acid crystal.Then with the speed of 4 DEG C/h, the feed liquid containing anhydrous citric acid crystal is lowered the temperature, and be cooled to 56 DEG C and maintain 15 minutes, start blowing.And logical solid-liquid separation is carried out to the magma after repairing and dry (hot blast 30 DEG C, 12 DEG C, cold wind, dry 10 minutes) obtain dry anhydrous citric acid crystal.After dry, the readily carbonizable substance of anhydrous citric acid crystal, moisture content and transmittance are in table 1.The face shaping of gained crystal is similar to Example 1.
Embodiment 4-5
The present embodiment is for illustration of the production method of anhydrous citric acid crystal provided by the invention.
According to the method for embodiment 1 evaporative crystallization is carried out to citric acid solution and the crystal in the magma obtained is repaired.Unlike, in embodiment 4 step (2), the temperature of magma is increased to 90 DEG C (increasing 20 DEG C), then continues to be cooled to 75 DEG C (reducing 25 DEG C); In embodiment 5 step (2), the temperature of magma is increased to 72 DEG C (increasing 2 DEG C), then continues to be cooled to 70 DEG C (reducing 2 DEG C).After dry, the readily carbonizable substance of anhydrous citric acid crystal, moisture content and transmittance are in table 1.The face shaping of embodiment 4 and embodiment 5 gained crystal is poorer than embodiment 1, but is better than comparative example 1.
Embodiment 6
The present embodiment is for illustration of the production method of anhydrous citric acid crystal provided by the invention.
According to the method for embodiment 1 evaporative crystallization is carried out to citric acid solution and the crystal in the magma obtained is repaired.Unlike, in step (2), first magma is heated up with the speed of 10 DEG C/h, and then with the speed of 8 DEG C/h, the feed liquid containing anhydrous citric acid crystal is lowered the temperature.After dry, the readily carbonizable substance of anhydrous citric acid crystal, moisture content and transmittance are in table 1.The face shaping of gained crystal is poorer than embodiment 1, but is better than comparative example 1.
Embodiment 7
The present embodiment is for illustration of the production method of anhydrous citric acid crystal provided by the invention.
According to the method for embodiment 1 evaporative crystallization is carried out to citric acid solution and the crystal in the magma obtained is repaired.Unlike, in step (2), in temperature-fall period, mixing speed is 30rpm.After dry, the readily carbonizable substance of anhydrous citric acid crystal, moisture content and transmittance are in table 1.The face shaping of gained crystal is poorer than embodiment 1, but is better than comparative example 1.
Embodiment 8
The present embodiment is for illustration of the production method of anhydrous citric acid crystal provided by the invention.
According to the method for embodiment 1 evaporative crystallization is carried out to citric acid solution and the crystal in the magma obtained is repaired.Unlike, in step (2), in temperature-fall period, mixing speed is 20rpm.After dry, the readily carbonizable substance of anhydrous citric acid crystal, moisture content and transmittance are in table 1.The face shaping of gained crystal is poorer than embodiment 1, but is better than comparative example 1.
Embodiment 9
The present embodiment is for illustration of the production method of anhydrous citric acid crystal provided by the invention.
According to the method for embodiment 1 evaporative crystallization is carried out to citric acid solution and the crystal in the magma obtained is repaired.Unlike, in step (2), only heat up do not lower the temperature to magma, repair time is identical with the reparation total time in embodiment.The face shaping of gained crystal is poorer than embodiment 1, but is better than comparative example 1.
Embodiment 10
The present embodiment is for illustration of the production method of anhydrous citric acid crystal provided by the invention.
According to the method for embodiment 1 evaporative crystallization is carried out to citric acid solution and the crystal in the magma obtained is repaired.Unlike, in step (2), directly carry out cooling process to magma, the temperature of reduction is 5 DEG C, and repair time is identical with the reparation total time in embodiment.The face shaping of gained crystal is poorer than embodiment 1, but is better than comparative example 1.
Comparative example 1
The production method of the anhydrous citric acid crystal that this comparative example provides for illustration of prior art.
Obtain anhydrous citric acid crystal according to method evaporative crystallization from citric acid solution of embodiment 1, terminate directly gained magma to be carried out centrifugal and dry afterwards unlike, step (1), obtain the anhydrous citric acid crystal of drying.After dry, the readily carbonizable substance of anhydrous citric acid crystal, moisture content and transmittance are in table 1.The microscope photograph of gained crystal as shown in Figure 2.
Table 1
| Embodiment/comparative example numbering | Readily carbonizable substance | Moisture content (% by weight) | Transmittance (%) |
| Embodiment 1 | 0.31 | 0.05 | 99.9 |
| Embodiment 2 | 0.3 | 0.06 | 99.9 |
| Embodiment 3 | 0.31 | 0.06 | 99.9 |
| Embodiment 4 | 0.4 | 0.07 | 99.3 |
| Embodiment 5 | 0.4 | 0.07 | 98.7 |
| Embodiment 6 | 0.45 | 0.09 | 99.1 |
| Embodiment 7 | 0.42 | 0.08 | 99.2 |
| Embodiment 8 | 0.45 | 0.09 | 99.0 |
| Embodiment 9 | 0.4 | 0.07 | 99.3 |
| Embodiment 10 | 0.4 | 0.07 | 99.1 |
| Comparative example 1 | 0.9 | 0.18 | 97.2 |
From in upper table, embodiment 1-10 and comparative example 1 are compared and can be found out, the readily carbonizable substance of the anhydrous citric acid crystal adopting method of the present invention to obtain and moisture content obtain the reduction of significance.Embodiment 1 is compared can be found out with embodiment 4-8, and control in the preferred scope of the present invention by the speed of the temperature of the temperature of rising, reduction, intensification and cooling and mixing speed, the quality of gained anhydrous citric acid crystal obtains further improvement.Further, embodiment 1 is compared can be found out with embodiment 9 and 10, the present invention adopts and repairs crystal the magma mode of lowering the temperature afterwards that first heats up, and effect is better.Therefore, method provided by the invention can reduce carrying secretly of wet crystal mother liquor effectively, reduces readily carbonizable substance and moisture content, improves the transmittance of crystal.
Compared by the crystal picture of the Fig. 2 by Fig. 1 of embodiment 1 and comparative example 1 and find out, the crystal outward appearance adopting method of the present invention to obtain is comparatively neat, not depression, therefore, it is possible to solve the residue problem of crystal depressed area mother liquor.
More than describe the preferred embodiment of the present invention in detail; but the present invention is not limited to the detail in above-mentioned embodiment, within the scope of technical conceive of the present invention; can carry out multiple simple variant to technical scheme of the present invention, these simple variant all belong to protection scope of the present invention.
It should be noted that in addition, each the concrete technical characteristic described in above-mentioned embodiment, in reconcilable situation, can be combined by any suitable mode.In order to avoid unnecessary repetition, the present invention illustrates no longer separately to various possible array mode.
In addition, also can carry out arbitrary combination between various different embodiment of the present invention, as long as it is without prejudice to thought of the present invention, it should be considered as content disclosed in this invention equally.
Claims (10)
1. the production method of an anhydrous citric acid crystal, the method comprises, under the condition of circulation stirring, citric acid solution is carried out crystallization, obtain magma, it is characterized in that, the method also comprises the initial temperature of change magma to repair the crystal in magma, obtains the feed liquid containing anhydrous citric acid crystal; The method of described change magma initial temperature comprises: the magma intensification 5-15 DEG C first will obtained after crystallization, then by the magma cooling 5-20 DEG C after intensification.
2. method according to claim 1, wherein, the speed magma obtained after crystallization heated up is 1-10 DEG C/h.
3. method according to claim 2, wherein, the speed magma obtained after crystallization heated up is 3-8 DEG C/h.
4. method according to claim 1, wherein, in the method for described change magma initial temperature, then the speed of the magma after heating up being lowered the temperature is 1-8 DEG C/h.
5. method according to claim 4, wherein, then the speed of the magma after heating up being lowered the temperature is 2-6 DEG C/h.
6. method according to claim 1, wherein, described crystallization is evaporative crystallization, and the initial temperature of described magma is 50-70 DEG C.
7. method according to claim 1, wherein, in the method for described change magma initial temperature, by lower at most than the initial temperature of magma 5 DEG C for the temperature of the magma obtained after the magma cooling after intensification.
8. method according to claim 1, wherein, described reparation is carried out under the condition stirred, and the speed of described stirring is 20-30rpm.
9. method according to claim 8, wherein, the speed of described stirring is 22-26rpm.
10. method according to claim 1, wherein, in described magma, the content of anhydrous citric acid crystal is 45-55 % by weight.
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| CN102976925A (en) * | 2012-12-06 | 2013-03-20 | 中粮生物化学（安徽）股份有限公司 | Anhydrous citric acid crystal and production method thereof |
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| IL155161A0 (en) * | 2003-03-31 | 2003-10-31 | Staley Mfg Co A E | A process for the recovery of citric acid |
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| CN102976925A (en) * | 2012-12-06 | 2013-03-20 | 中粮生物化学（安徽）股份有限公司 | Anhydrous citric acid crystal and production method thereof |
| CN102964242A (en) * | 2012-12-07 | 2013-03-13 | 中粮生物化学（安徽）股份有限公司 | Citric acid crystal and production method thereof |
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