CN102580345A - Crystallization tower for purifying phosphoric acid - Google Patents
Crystallization tower for purifying phosphoric acid Download PDFInfo
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- CN102580345A CN102580345A CN2012100116583A CN201210011658A CN102580345A CN 102580345 A CN102580345 A CN 102580345A CN 2012100116583 A CN2012100116583 A CN 2012100116583A CN 201210011658 A CN201210011658 A CN 201210011658A CN 102580345 A CN102580345 A CN 102580345A
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Abstract
The invention relates to a crystallization tower for purifying phosphoric acid. The crystallization tower comprises a tower body, one stirrer, a heater and a driving mechanism, wherein the tower body is divided into a cooling crystallization section, a separating purification section and a crystal melting section; the cooling crystallization section is arranged at the upper part of the tower body; the crystal melting section is arranged at the lower part of the tower body; the separating purification section is arranged between the cooling crystallization section and the crystal melting section; a feeding hole and a coolant inlet are arranged at the lower part of the cooling crystallization section of the tower body; the coolant inlet is arranged above the feeding hole; the upper part of the cooling crystallization section of the tower body is provided with a raffinate and coolant discharge hole; the bottom of the crystal melting section of the tower body is provided with a purified phosphoric acid outlet; the main body part of the stirrer is arranged in the tower body; one end of the stirrer extends out of the tower body and is connected with a speed reducer of the driving mechanism; and the heater is arranged on the tower body and is positioned on the crystal melting section of the tower body.
Description
Technical field
The invention belongs to phosphoric acid purification device, particularly a kind of crystallizing tower that adopts fusion-crystallization method purifying phosphoric acid.
Background technology
The device of fusion-crystallization method purifying phosphoric acid comprises common jacket type crystallizer, coiled pipe cooler crystallizer, laminar crystallizer and liquid membrane crystal tower etc.Common jacket type crystallizer and coiled pipe cooler crystallizer are that cooling medium is fed chuck or coiled pipe, through the partition heat exchange, make the phosphoric acid solution crystallisation by cooling; This type of cooler crystallizer heat-transfer surface is easy to fouling, thereby causes heat-transfer effect poor, and production capacity is little; In addition, though can reach purity requirement through the operation that repeatedly is recrystallized, product yield is low; Operating procedure is numerous and diverse, and inconvenience is adopted in commercial production.Laminar crystallizer and liquid membrane crystal tower are used for purifying phosphoric acid; Said phosphoric acid material circulates in laminar crystallizer and liquid membrane crystal tower, crystallization and purification, but this type of crystallization plays the technological requirement strictness; Must be at the temperature control curve condition of the strictness work of finishing drilling; And need multi-pass operation just can reach purity requirement, be not easy to continuous production, and the purifying phosphoric acid yield is still not high.
Summary of the invention
The objective of the invention is to overcome the deficiency of prior art, a kind of novel crystallization tower that is used for purifying phosphoric acid is provided,, reduce energy consumption, simplify the operation, be convenient to suitability for industrialized production to improve the yield of purifying phosphoric acid.
The crystallizing tower that is used for purifying phosphoric acid according to the invention comprises tower body, agitator, heater and driving mechanism, and said tower body is divided into the crystallisation by cooling section, separates rectifying section and crystal melt zone; The crystallisation by cooling section is positioned at tower body top, and the crystal melt zone is positioned at the tower body bottom, separates rectifying section between crystallisation by cooling section and crystal melt zone; The crystallisation by cooling pars infrasegmentalis of tower body is provided with charging aperture and refrigerant inlet; Said refrigerant inlet is positioned on the charging aperture, and the crystallisation by cooling section top of tower body is provided with raffinate and refrigerant floss hole, and the crystal melt zone bottom of tower body is provided with the purifying phosphoric acid outlet; Said agitator is one; Its main part is installed in the tower body, and the one of which end stretches out tower body and is connected with the decelerator of driving mechanism, and said heater is installed on the tower body and is positioned at the crystal melt zone of tower body.
In order to strengthen the settling property of half water phosphoric acid crystal, make the purification process stable operation of phosphoric acid, preferably the crystallizing tower of said structure to be tilted to install, test shows, preferred 5 °～20 ° of the angle θ that the crystallizing tower tower body tilts with respect to vertical.
The crystallizing tower that is used for purifying phosphoric acid according to the invention, its tower body are cylindrical body, and the bottom manufacturing materials of said cylindrical body is a polytetrafluoroethylene (PTFE), and peripheral manufacturing materials is any in polyethylene, Merlon, polypropylene, the polytetrafluoroethylene (PTFE).
The crystallizing tower that is used for purifying phosphoric acid according to the invention, the agitator of preferred following structure:
Said agitator comprises skeleton, sleeve, blade and scrapes part; Blade is a multi-disc; The two ends of each sheet blade all are equipped with one and scrape part, the quantity of the quantity=blade of sleeve+1, and said sleeve and blade alternately are sleeved on the skeleton; And be provided with sealing ring between sleeve and the blade, each sleeve, blade are realized fixing through the thread segment of skeleton end and the combination of nut.
The agitator of said structure; The quantity of its blade is according to the length decision of skeleton blade construction section; Spacing to satisfy between the adjacent blades is exceeded at 50～200mm, and its blade preferred class is similar to the shape of rhombus, and said blade centre is provided with the hole that is used to connect skeleton; Its two ends are respectively arranged with and are used to install the hole of scraping part, and two the hole scrape part is installed is axial symmetry with the center line in the hole that connects skeleton; The said part of scraping is the multidiameter shapes that the different cylinder of two sections diameters constitutes, wherein the less relatively one section cylinder plug-in mounting of diameter and being fixed in the hole that the blade two ends are provided with; Constituting one section relatively large cylindrical outside of the diameter scrape part and the gap between the tower body inwall is 1～3mm.Said skeleton is made by stainless steel, said sleeve, blade and scrape part and make with polytetrafluoroethylene (PTFE).
The crystallizing tower that is used for purifying phosphoric acid according to the invention, its heater is made up of tubular matrix, the heating resistor and the temperature thermocouple that are installed on the tubular matrix, and said tubular matrix is made by the good metal material of heat conductivility.
The crystallizing tower that is used for purifying phosphoric acid according to the invention; Purification mechanism mainly contains recrystallization, countercurrent washing, (crystal is when the temperature of a little higher than primary crystallization in sweating; The constantly fusing and the phenomenon of oozing out is sweating of its inner low melting point impurity; Sweating is further purified crystal), operation principle is following:
Phosphoric acid solution to be clean is got in the tower by the charging aperture of crystallizing tower; Get into said crystallisation by cooling section with moving upward from the heat fusing phosphoric acid liquid at the bottom of the tower; In the crystallisation by cooling section, phosphoric acid solution directly contacts with refrigerant, precipitation of phosphorus acid crystal when it is cooled to crystallization temperature; The phosphoric acid crystal of being separated out moves downward to get into successively under the effect of gravity and separates rectifying section and crystal melt zone; The phosphoric acid crystal carries out sweating at the separation rectifying section purifies, and carried out countercurrent washing by the fusion phosphoric acid liquid from the crystal melt zone simultaneously, thereby the purity of phosphoric acid crystal is increasingly high; The phosphoric acid crystal that gets into the crystal melt zone is melted, and a part is discharged as product, and a part rises as refluxing.Half water phosphoric acid crystal constantly repeats crystallization-fusing-crystallization process in crystallizing tower, can realize purifying.
The crystallizing tower that is used for purifying phosphoric acid according to the invention, it is operated as follows:
The phosphoric acid solution to be clean of uniform temperature is imported in the crystallizing tower through delivery pump; After being full of phosphoric acid solution in the crystallizing tower; Close delivery pump, the agitator of opening crystallizing tower stirs, and through the system that is made up of pump, heat exchanger, phase-splitting container refrigerant is imported the crystallisation by cooling section of crystallizing tower then; By the desired rate of temperature fall of technology the temperature of refrigerant being reduced to the desired temperature of technology again cools off phosphoric acid solution; And make the circulation of refrigerant between crystallizing tower crystallisation by cooling section and phase-splitting container, when the phosphoric acid solution of crystallisation by cooling section is cooled to hypersaturated state, the phosphoric acid crystal seed is added the crystallisation by cooling section, when the crystallisation by cooling section no longer produces new crystal; Open delivery pump phosphoric acid solution to be clean is continued the input crystallizing tower; When crystal bed in the crystallizing tower is accumulated to crystallisation by cooling section lower end, close delivery pump, open the heater of crystallizing tower, crystallization control tower crystal melt zone temperature is in required temperature, when from the purifying phosphoric acid outlet of crystal melt zone bottom during the constant standard that reaches the purifying phosphoric acid defined of the phosphoric acid sample of getting; Then continuously phosphoric acid solution to be clean is imported crystallizing tower, and the continuous output of purifying phosphoric acid crystallizing tower.
Under the effect of the system that forms by pump, heat exchanger, phase-splitting container; The crystallisation by cooling section that refrigerant gets into crystallizing tower from the refrigerant inlet; The raffinate that refrigeration crystallization process produced reaches at the refrigerant that is introduced into the crystallisation by cooling section and discharges entering phase-splitting container from raffinate and refrigerant floss hole; Refrigerant recycles under the effect of pump, the temperature that gets into the refrigerant of crystallizing tower through the heat exchanger control that is arranged on the circulation line.
The present invention has following beneficial effect:
1, the structure of crystallizing tower according to the invention meets fusion-crystallization method purification mechanism-recrystallization, countercurrent washing and sweating, particularly can fully satisfy the requirement of sweating mechanism, thereby impurity removal percentage is high.
2, the crystallisation by cooling section of crystallizing tower according to the invention adopts the type of cooling that refrigerant and phosphoric acid to be clean directly contact, thereby not only cooling effectiveness is high, can reduce energy consumption, and it is irregular with the mother liquor temperature effectively to avoid the crystallisation by cooling section to scab.
3, crystallizing tower inclination certain angle according to the invention is installed, can be strengthened the settling property of crystal, guarantee that solid-liquid two is stablized counter-current flow mutually in the tower, improve and separate refining effect.
4, the power of agitator little, be convenient to processing and fabricating, cost low, be easy to amplify.
5, not only purification operations is simple for crystallizing tower according to the invention, but and the serialization steady production, thereby be convenient in commercial production, use.
Description of drawings
Fig. 1 is the structural representation that is used for the crystallizing tower of purifying phosphoric acid according to the invention, and among the figure, a section is the crystallisation by cooling section, and the b section is for separating rectifying section, and the c section is the crystal melt zone;
Fig. 2 is the structural representation that is used for the crystallizing tower agitator of purifying phosphoric acid according to the invention;
Fig. 3 is shape, the organigram of skeleton in the agitator;
Fig. 4 is the vertical view of Fig. 3;
Fig. 5 is shape, the organigram of agitator middle sleeve and sealing ring;
Fig. 6 is the B-B cutaway view of Fig. 5;
Fig. 7 is shape, the organigram of blade in the agitator;
Fig. 8 is the vertical view of Fig. 7;
Fig. 9 is shape, an organigram of scraping part in the agitator;
Figure 10 is the vertical view of Fig. 9;
Figure 11 is shape, the organigram that is used for the crystallizing tower heater of purifying phosphoric acid according to the invention;
Figure 12 is the A-A cutaway view of Figure 11.
Among the figure; The 1-tower body, 2-agitator (2-1: skeleton, 2-2: sealing ring, 2-3: sleeve, 2-4: blade, 2-4-1: the hole, the 2-4-2 that connect skeleton: the hole, the 2-5 that scrape part are installed: scrape part), 3-refrigerant inlet; 4-raffinate and refrigerant floss hole; The 5-decelerator, 6-motor, 7-charging aperture; The outlet of 8-purifying phosphoric acid, and the 9-heater (9-1: heating resistor, 9-2: temperature thermocouple), the 10-support.
The specific embodiment
Structure and the application that is used for the crystallizing tower of purifying phosphoric acid according to the invention is described further through embodiment below in conjunction with accompanying drawing.
Embodiment 1
In the present embodiment, the structure of crystallizing tower that is used for purifying phosphoric acid is as shown in Figure 1, comprises tower body 1, agitator 2, heater 9 and driving mechanism.
Said tower body 1 is a cylinder-like body, and the manufacturing materials of its bottom and periphery is polytetrafluoroethylene (PTFE), and tower body 1 is divided into crystallisation by cooling section a, separates rectifying section b and crystal melt zone c; The crystallisation by cooling section is positioned at tower body top, and its length is 0.2m, and the crystal melt zone is positioned at the tower body bottom; Its length is 0.15m, separates rectifying section between crystallisation by cooling section and crystal melt zone, and its length is 1m; The crystallisation by cooling pars infrasegmentalis of tower body is provided with charging aperture 7 and refrigerant inlet 3; Said refrigerant inlet is positioned on the charging aperture 7, and the crystallisation by cooling section top of tower body is provided with raffinate and refrigerant floss hole 4, and the crystal melt zone bottom of tower body is provided with purifying phosphoric acid outlet 8.
The structure of said agitator 2 is as shown in Figure 2, comprises skeleton 2-1, sleeve 2-3, blade 2-4 and scrapes part 2-5; Skeleton 2-1 makes with the 316L stainless steel, and for the cross section is foursquare cylinder, its lower end is provided with thread segment, like Fig. 3, shown in Figure 4; Sleeve 2-3 makes with polytetrafluoroethylene (PTFE), is circular tube structure, like Fig. 5, shown in Figure 6; Blade 2-4 makes with polytetrafluoroethylene (PTFE); Its shape such as Fig. 7, shown in Figure 8 are similar to rhombus, and its centre is provided with the hole 2-4-1 that is used to connect skeleton; Its two ends are respectively arranged with and are used to install the hole 2-4-2 that scrapes part, and two the hole scrape part is installed is axial symmetry with the center line in the hole that connects skeleton; Scraping part 2-5 and make with polytetrafluoroethylene (PTFE), is two sections multidiameter shapes that the different cylinder of diameter constitutes, like Fig. 9, shown in Figure 10; The length of skeleton blade construction section is 1.1m, and the quantity of blade is 8, and at skeleton blade construction section, the spacing between the adjacent blades is identical, is 100mm, and the quantity of scraping part is the twice of blade quantity, the quantity of the quantity=blade of sleeve+1; Said sleeve and blade alternately are sleeved on the skeleton, and are provided with sealing ring 2-2 between sleeve and the blade, and each sleeve, blade are realized fixing through the thread segment of skeleton 2-1 end and the combination of nut; The two ends of each sheet blade all are equipped with one and scrape part; Constitute one section less relatively cylinder plug-in mounting of the diameter scrape part and be fixed in the hole that blade 2-4 two ends are provided with, constitute one section relatively large cylindrical outside of the diameter of scraping part and the gap 2mm between the tower body inwall.
Said heater 9 is made up of tubular matrix 9-1, heating resistor 9-2 and temperature thermocouple 9-3; The tubular matrix is done by the good aluminum of heat conductivility; The quantity of heating resistor 9-2 is to satisfy the decision of heating power demand, and each heating resistor and temperature thermocouple are installed on the tubular matrix (sees Figure 11, Figure 12).
Said driving mechanism is made up of motor 6 and decelerator 5, and decelerator is a gear reduction unit.
The assembling mode of each parts:
Tower body 1 is installed on the support 10, and its mounting means is with respect to 15 ° of (see figure 1)s of vertical inclination; Agitator 2 is one, and its main part is installed in the tower body, and its lower end is installed on the bearing that tower body bottom is provided with, and its upper end is stretched out tower body and is connected with the decelerator 5 of driving mechanism, and heater 9 is installed on the tower body and around the crystal melt zone of tower body.
Using the said crystallizing tower of present embodiment to use phosphoric acid quality concentration is that 85% technical grade thermal phosphoric acid prepares electron-level phosphoric acid, and the impurity content in the said industrial phosphoric acid is seen table 1.
Table 1: PHOSPHORIC ACID TECH.GRADE impurity content
| Impurity | Content (ppb) | Impurity | Content (ppb) |
| Li | 4819 | Co | 135 |
| Na | 4670 | Ni | 457 |
| Mg | 7030 | Cu | 42 |
| Al | 641 | Zn | 1632 |
| K | 106300 | As | 112900 |
| Ca | 22330 | Sr | 455 |
| Cr | 832 | Cd | 22 |
| Mn | 173 | Sb | 8830 |
| Fe | 5275 | Pb | 2566 |
Processing step is following:
1. dearsenification
In temperature is 20 ℃ industrial phosphoric acid, add phosphorus pentasulfide, under agitation (500r/min) in 20 ℃ of reactions of normal pressure 120min, and the addition of said phosphorus pentasulfide is 5 times of mole of contained arsenic in the industrial phosphoric acid; After reaction time expires, add the diatomite of phosphoric acid quality 5%, leave standstill 10min; Suction filtration then; Obtain to suction filtration and to drip hydrogen peroxide solution in the phosphoric acid solution, the dripping quantity of hydrogen peroxide solution is 1% of a said phosphoric acid solution quality, continue after remove the solid particle that suspends in the phosphoric acid solution with the membrane filtration of 0.1 μ m; Through detecting, arsenic content is 427ppb in the phosphoric acid after the processing;
2. the processing again of dearsenification phosphoric acid solution
Add hydrochloric acid solution in the phosphoric acid solution after dearsenification and mix, be heated to 21 ℃ then, the mass concentration of said hydrochloric acid solution is 37%, the addition of hydrochloric acid solution with hydrochloric 0.2% of the phosphoric acid quality in the phosphoric acid solution that reaches exceed;
3. use crystallizing tower purifying phosphoric acid solution
Will through the temperature after 2. step is handled be 21 ℃ phosphoric acid solution through delivery pump in the said crystallizing tower of charging aperture 7 input; After being full of phosphoric acid solution in the crystallizing tower; Close delivery pump; The agitator 2 of opening crystallizing tower stirs (6r/min); Be the crystallisation by cooling sections of 21 ℃ of refrigerant tasteless kerosenes through the system that forms by pump, heat exchanger, phase-splitting container with temperature then from refrigerant inlet 3 input crystallizing towers; By the rate of temperature fall of 3 ℃/min the temperature of refrigerant is reduced to-5 ℃ again phosphoric acid solution is cooled off, and make the circulation of refrigerant between crystallizing tower crystallisation by cooling section and phase-splitting container, the phosphoric acid crystal seed is added the crystallisation by cooling section from the tower body top when the phosphoric acid solution of crystallisation by cooling section is cooled to 20 ℃ (during hypersaturated states); The addition of phosphoric acid crystal seed is 10% of a crystallisation by cooling section phosphoric acid solution quality; When said crystallisation by cooling section no longer produces new crystal, open delivery pump and will continue the input crystallizing tower from crossing charging aperture 7 through the phosphoric acid solution after 2. step is handled,, crystal bed in the crystallizing tower closes the heater 9 of delivery pump, unlatching crystallizing tower when being accumulated to crystallisation by cooling section lower end; Crystallization control tower crystal melt zone temperature is at 35 ℃; When getting from 8 of the purifying phosphoric acid outlets of said crystal melt zone bottom that the phosphoric acid sample is constant to reach the said electron-level phosphoric acid standard of table 2, then continuously will be through the phosphoric acid solution after 2. step is handled from charging aperture 7 input crystallizing towers, and continuously electron-level phosphoric acid is exported crystallizing tower.
The prepared electron-level phosphoric acid of present embodiment is a phosphoric acid quality concentration at 91% fluid product, and the single yield can reach 55.1%, and impurity content is seen table 2.
Table 2: electron-level phosphoric acid impurity content analysis result
| Impurity | Product impurity content (ppb) | Electron-level phosphoric acid standard (ppb) |
| Li | 43 | 100 |
| Na | 375 | 500 |
| Mg | 87 | 200 |
| Al | 59 | 250 |
| K | 346 | 450 |
| Ca | 95 | 250 |
| |
10 | 200 |
| |
7 | 100 |
| Fe | 253 | 500 |
| |
3 | 50 |
| Ni | 4 | 200 |
| |
5 | 50 |
| |
8 | 400 |
| As | 45 | 50 |
| Sr | 14 | 100 |
| |
3 | 450 |
| Sb | 81 | 5000 |
| |
9 | 300 |
In the present embodiment, the structure of crystallizing tower that is used for purifying phosphoric acid is as shown in Figure 1, comprises tower body 1, agitator 2, heater 9 and driving mechanism.With embodiment 1 difference be: tower body 1 tilts 5 ° with respect to vertical.
Use the said crystallizing tower of present embodiment to use with embodiment 1 identical industrial phosphoric acid and prepare electron-level phosphoric acid, processing step is following:
1. dearsenification
In temperature is 40 ℃ industrial phosphoric acid, add phosphorus pentasulfide, under agitation (500r/min) in 40 ℃ of reactions of normal pressure 100min, and the addition of said phosphorus pentasulfide is 3 times of mole of contained arsenic in the industrial phosphoric acid; After reaction time expires, add the diatomite of phosphoric acid quality 8%, leave standstill 20min; Suction filtration then; Obtain to suction filtration and to drip hydrogen peroxide solution in the phosphoric acid solution, the dripping quantity of hydrogen peroxide solution is 0.5% of a said phosphoric acid solution quality, continue after remove the solid particle that suspends in the phosphoric acid solution with the membrane filtration of 0.3 μ m; Through detecting, arsenic content is 431ppb in the phosphoric acid after the processing;
2. the processing again of dearsenification phosphoric acid solution
Add hydrofluoric acid solution in the phosphoric acid solution after dearsenification and mix, be heated to 25 ℃ then, the mass concentration of said hydrofluoric acid solution is 40%, and the addition of hydrofluoric acid solution reaches 1% of phosphoric acid quality in the phosphoric acid solution with institute's hydrofluoric acid containing and exceeds;
3. use crystallizing tower purifying phosphoric acid solution
To be that 25 ℃ phosphoric acid solution is imported in the said crystallizing tower from charging aperture 7 through delivery pump through the temperature after 2. step is handled; After being full of phosphoric acid solution in the crystallizing tower; Close delivery pump; The agitator 2 of opening crystallizing tower stirs (10r/min); Then through the system that forms by pump, heat exchanger, phase-splitting container with temperature be 25 ℃ refrigerant chlorine n-hexane from the crystallisation by cooling section of refrigerant inlet 3 input crystallizing towers, by the rate of temperature fall of 2 ℃/min the temperature of refrigerant is reduced to 0 ℃ again phosphoric acid solution is cooled off, and make the circulation of refrigerant between crystallizing tower crystallisation by cooling section and phase-splitting container; When the phosphoric acid solution of crystallisation by cooling section is cooled to 18 ℃ (during hypersaturated states); The phosphoric acid crystal seed is added the crystallisation by cooling section from the tower body top, the addition of phosphoric acid crystal seed is 5% of a crystallisation by cooling section phosphoric acid solution quality, when said crystallisation by cooling section no longer produces new crystal; Opening delivery pump will continue from charging aperture 7 input crystallizing towers through the phosphoric acid solution after 2. step is handled; When crystal bed in the crystallizing tower is accumulated to crystallisation by cooling section lower end, close delivery pump, open the heater 9 of crystallizing tower, crystallization control tower crystal melt zone temperature is at 32 ℃, when getting from 8 of the purifying phosphoric acid outlets of said crystal melt zone bottom that the phosphoric acid sample is constant to reach the said electron-level phosphoric acid standard of table 3; Then will import crystallizing towers from charging aperture 7 through the phosphoric acid solution after 2. step is handled continuously, and continuously electron-level phosphoric acid exported crystallizing tower.
The prepared electron-level phosphoric acid of present embodiment is a phosphoric acid quality concentration at 90.3% fluid product, and the single yield can reach 51.2%, and impurity content is seen table 3.
Table 3: electron-level phosphoric acid impurity content analysis result
| Impurity | Product impurity content (ppb) | Electron-level phosphoric acid standard (ppb) |
| Li | 45 | 100 |
| Na | 387 | 500 |
| Mg | 91 | 200 |
| Al | 57 | 250 |
| K | 349 | 450 |
| Ca | 101 | 250 |
| Cr | 11 | 200 |
| |
8 | 100 |
| Fe | 257 | 500 |
| |
5 | 50 |
| |
6 | 200 |
| Cu | 4 | 50 |
| |
7 | 400 |
| As | 43 | 50 |
| Sr | 15 | 100 |
| |
2 | 450 |
| Sb | 83 | 5000 |
| |
10 | 300 |
In the present embodiment, the structure of crystallizing tower that is used for purifying phosphoric acid is as shown in Figure 1, comprises tower body 1, agitator 2, heater 9 and driving mechanism.With embodiment 1 difference be: tower body 1 tilts 20 ° with respect to vertical.
Use the said crystallizing tower of present embodiment to use with embodiment 1 identical industrial phosphoric acid and prepare electron-level phosphoric acid, processing step is following:
1. dearsenification
In temperature is 60 ℃ industrial phosphoric acid, add phosphorus pentasulfide, under agitation (500r/min) in 60 ℃ of reactions of normal pressure 60min, and the addition of said phosphorus pentasulfide is 2 times of mole of contained arsenic in the industrial phosphoric acid; After reaction time expires, add the diatomite of phosphoric acid quality 10%, leave standstill 30min; Suction filtration then; Obtain to suction filtration and to drip hydrogen peroxide solution in the phosphoric acid solution, the dripping quantity of hydrogen peroxide solution is 0.1% of a said phosphoric acid solution quality, continue after remove the solid particle that suspends in the phosphoric acid solution with the membrane filtration of 0.5 μ m; Through detecting, arsenic content is 443ppb in the phosphoric acid after the processing;
2. the processing again of dearsenification phosphoric acid solution
Add hydrochloric acid solution in the phosphoric acid solution after dearsenification and mix, be heated to 30 ℃ then, the mass concentration of said hydrochloric acid solution is 37%, the addition of hydrochloric acid solution with hydrochloric 0.1% of the phosphoric acid quality in the phosphoric acid solution that reaches exceed;
3. use crystallizing tower purifying phosphoric acid solution
To be that 30 ℃ phosphoric acid solution is imported in the said crystallizing tower from charging aperture 7 through delivery pump through the temperature after 2. step is handled; After being full of phosphoric acid solution in the crystallizing tower; Close delivery pump; The agitator 2 of opening crystallizing tower stirs (15r/min); Then through the system that forms by pump, heat exchanger, phase-splitting container with temperature be 30 ℃ refrigerant pentane from the crystallisation by cooling section of refrigerant inlet 3 input crystallizing towers, by the rate of temperature fall of 0.5 ℃/min the temperature of refrigerant is reduced to 5 ℃ again phosphoric acid solution is cooled off, and make the circulation of refrigerant between crystallizing tower crystallisation by cooling section and phase-splitting container; When the phosphoric acid solution of crystallisation by cooling section is cooled to 15 ℃ (during hypersaturated states); The phosphoric acid crystal seed is added the crystallisation by cooling section from the tower body top, the addition of phosphoric acid crystal seed is 1% of a crystallisation by cooling section phosphoric acid solution quality, when said crystallisation by cooling section no longer produces new crystal; Open delivery pump and will continue the input crystallizing tower from charging aperture 7 through the phosphoric acid solution after 2. step is handled; When crystal bed in the crystallizing tower is accumulated to crystallisation by cooling section lower end, close delivery pump, open the heater 9 of crystallizing tower, crystallization control tower crystal melt zone temperature is at 30 ℃, when getting from 8 of the purifying phosphoric acid outlets of said crystal melt zone bottom that the phosphoric acid sample is constant to reach the said electron-level phosphoric acid standard of table 4; Then will import crystallizing towers from charging aperture 7 through the phosphoric acid solution after 2. step is handled continuously, and continuously electron-level phosphoric acid exported crystallizing tower.
The prepared electron-level phosphoric acid of present embodiment is a phosphoric acid quality concentration at 88.5% fluid product, and yield can reach 45.8%, and impurity content is seen table 4.
Table 4: electron-level phosphoric acid impurity content analysis result
| Impurity | Product impurity content (ppb) | Electron-level phosphoric acid standard (ppb) |
| Li | 47 | 100 |
| Na | 391 | 500 |
| Mg | 87 | 200 |
| Al | 62 | 250 |
| K | 341 | 450 |
| Ca | 95 | 250 |
| |
9 | 200 |
| |
7 | 100 |
| Fe | 243 | 500 |
| |
7 | 50 |
| |
5 | 200 |
| |
3 | 50 |
| |
9 | 400 |
| As | 41 | 50 |
| Sr | 18 | 100 |
| |
3 | 450 |
| Sb | 79 | 5000 |
| |
7 | 300 |
In the foregoing description 1,2,3, the impurity metal ion content in the electron-level phosphoric acid product obtains with the icp ms (ICP-MS) of generally acknowledging in industry analysis; Electron-level phosphoric acid standard in table 2～table 4 is the standard of Japanese enterprises buying electron-level phosphoric acid.
Claims (10)
1. crystallizing tower that is used for purifying phosphoric acid; It is characterized in that comprising tower body (1), agitator (2), heater (9) and driving mechanism, said tower body is divided into the crystallisation by cooling section, separates rectifying section and crystal melt zone, and the crystallisation by cooling section is positioned at tower body top; The crystal melt zone is positioned at the tower body bottom; Separate rectifying section between crystallisation by cooling section and crystal melt zone, the crystallisation by cooling pars infrasegmentalis of tower body is provided with charging aperture (7) and refrigerant inlet (3), and said refrigerant inlet is positioned on the charging aperture (7); The crystallisation by cooling section top of tower body is provided with raffinate and refrigerant floss hole (4); The crystal melt zone bottom of tower body is provided with purifying phosphoric acid outlet (8), and said agitator (2) is one, and its main part is installed in the tower body; The one of which end stretches out tower body and is connected with the decelerator (5) of driving mechanism, and said heater (9) is installed on the tower body and is positioned at the crystal melt zone of tower body.
2. according to the said crystallizing tower that is used for purifying phosphoric acid of claim 1, it is characterized in that tower body (1) is 5 °～20 ° with respect to the angle θ that vertical tilts.
3. according to claim 1 or the 2 said crystallizing towers that are used for purifying phosphoric acid; It is characterized in that tower body (1) is cylindrical body; The bottom manufacturing materials of said cylindrical body is a polytetrafluoroethylene (PTFE), and peripheral manufacturing materials is any in polyethylene, Merlon, polypropylene, the polytetrafluoroethylene (PTFE).
4. according to claim 1 or the 2 said crystallizing towers that are used for purifying phosphoric acid; It is characterized in that agitator (2) comprises skeleton (2-1), sleeve (2-3), blade (2-4) and scrapes part (2-5), blade is a multi-disc, and the two ends of each sheet blade all are equipped with one and scrape part; The quantity of the quantity=blade of sleeve+1; Said sleeve and blade alternately are sleeved on the skeleton, and are provided with sealing ring (2-2) between sleeve and the blade, and each sleeve, blade are realized fixing through the thread segment of skeleton (2-1) end and the combination of nut.
5. according to the said crystallizing tower that is used for purifying phosphoric acid of claim 4; It is characterized in that of the length decision of the quantity of said blade (2-4) according to skeleton blade construction section; Spacing to satisfy between the adjacent blades is exceeded at 50～200mm, and the shape of said blade (2-4) is similar to rhombus, and its centre is provided with the hole (2-4-1) that is used to connect skeleton; Its two ends are respectively arranged with and are used to install the hole (2-4-2) of scraping part, and two the hole scrape part is installed is axial symmetry with the center line in the hole that connects skeleton;
Scrape part (2-5) and be the multidiameter shapes that two sections different cylinders of diameter constitute, wherein the less relatively one section cylinder plug-in mounting of diameter and being fixed in the hole that blade (2-4) two ends are provided with; Constituting one section relatively large cylindrical outside of the diameter scrape part and the gap between the tower body inwall is 1～3mm.
6. according to the said crystallizing tower that is used for purifying phosphoric acid of claim 4, it is characterized in that said skeleton (2-1) made by stainless steel, said sleeve (2-3), blade (2-4) and scrape part (2-5) and make with polytetrafluoroethylene (PTFE).
7. according to the said crystallizing tower that is used for purifying phosphoric acid of claim 5, it is characterized in that said skeleton (2-1) made by stainless steel, said sleeve (2-3), blade (2-4) and scrape part (2-5) and make with polytetrafluoroethylene (PTFE).
8. according to claim 1 or the 2 said crystallizing towers that are used for purifying phosphoric acid; It is characterized in that heater (9) is made up of tubular matrix (9-1), the heating resistor (9-2) and the temperature thermocouple (9-3) that are installed on the tubular matrix, said tubular matrix is made by the good metal material of heat conductivility.
9. according to the said crystallizing tower that is used for purifying phosphoric acid of claim 3; It is characterized in that heater (9) is made up of tubular matrix (9-1), the heating resistor (9-2) and the temperature thermocouple (9-3) that are installed on the tubular matrix, said tubular matrix is made by the good metal material of heat conductivility.
10. according to the said crystallizing tower that is used for purifying phosphoric acid of claim 4; It is characterized in that heater (9) is made up of tubular matrix (9-1), the heating resistor (9-2) and the temperature thermocouple (9-3) that are installed on the tubular matrix, said tubular matrix is made by the good metal material of heat conductivility.
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| CN201210011658.3A CN102580345B (en) | 2012-01-13 | 2012-01-13 | Crystallization tower for purifying phosphoric acid |
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| CN201210011658.3A CN102580345B (en) | 2012-01-13 | 2012-01-13 | Crystallization tower for purifying phosphoric acid |
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| CN102580345B CN102580345B (en) | 2014-04-30 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103028271A (en) * | 2012-12-29 | 2013-04-10 | 北京化工大学 | Multi-stage countercurrent crystallizer provided with sieve plates |
| CN103754849A (en) * | 2013-12-30 | 2014-04-30 | 广西明利化工有限公司 | Electronic grade phosphoric acid infrared heating crystallizing device |
| CN103771373A (en) * | 2013-12-30 | 2014-05-07 | 广西明利化工有限公司 | Electronic-grade phosphoric acid hot air heating crystallizing device |
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| EP1141426A1 (en) * | 1999-01-08 | 2001-10-10 | Aluminium Pechiney | Method and device for purifying aluminium by segregation |
| CN101774555A (en) * | 2010-02-02 | 2010-07-14 | 天津大学 | Method for preparing electronic grade phosphoric acid through liquid membrane crystallization |
| CN201543264U (en) * | 2009-11-23 | 2010-08-11 | 岳阳市钾盐科学研究所 | Air cooling crystallization tower |
| CN202492368U (en) * | 2012-01-13 | 2012-10-17 | 四川大学 | Crystallization tower for purifying phosphoric acid |
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| EP1141426A1 (en) * | 1999-01-08 | 2001-10-10 | Aluminium Pechiney | Method and device for purifying aluminium by segregation |
| CN201543264U (en) * | 2009-11-23 | 2010-08-11 | 岳阳市钾盐科学研究所 | Air cooling crystallization tower |
| CN101774555A (en) * | 2010-02-02 | 2010-07-14 | 天津大学 | Method for preparing electronic grade phosphoric acid through liquid membrane crystallization |
| CN202492368U (en) * | 2012-01-13 | 2012-10-17 | 四川大学 | Crystallization tower for purifying phosphoric acid |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103028271A (en) * | 2012-12-29 | 2013-04-10 | 北京化工大学 | Multi-stage countercurrent crystallizer provided with sieve plates |
| CN103028271B (en) * | 2012-12-29 | 2015-01-14 | 北京化工大学 | Multi-stage countercurrent crystallizer provided with sieve plates |
| CN103754849A (en) * | 2013-12-30 | 2014-04-30 | 广西明利化工有限公司 | Electronic grade phosphoric acid infrared heating crystallizing device |
| CN103771373A (en) * | 2013-12-30 | 2014-05-07 | 广西明利化工有限公司 | Electronic-grade phosphoric acid hot air heating crystallizing device |
| CN103754849B (en) * | 2013-12-30 | 2015-09-16 | 广西明利化工有限公司 | A kind of electron-level phosphoric acid infrared heating crystallization apparatus |
| CN103771373B (en) * | 2013-12-30 | 2015-10-28 | 广西明利化工有限公司 | A kind of electron-level phosphoric acid Hot-blast Heating crystallization apparatus |
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|---|---|
| CN102580345B (en) | 2014-04-30 |
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