CN115448375B - Method and device for continuously crystallizing ferrous sulfate in sulfuric acid process titanium dioxide titanium liquid - Google Patents
Method and device for continuously crystallizing ferrous sulfate in sulfuric acid process titanium dioxide titanium liquid Download PDFInfo
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- CN115448375B CN115448375B CN202211110377.3A CN202211110377A CN115448375B CN 115448375 B CN115448375 B CN 115448375B CN 202211110377 A CN202211110377 A CN 202211110377A CN 115448375 B CN115448375 B CN 115448375B
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- 239000007788 liquid Substances 0.000 title claims abstract description 151
- 235000003891 ferrous sulphate Nutrition 0.000 title claims abstract description 98
- 239000011790 ferrous sulphate Substances 0.000 title claims abstract description 98
- 229910000359 iron(II) sulfate Inorganic materials 0.000 title claims abstract description 98
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 title claims abstract description 76
- 238000000034 method Methods 0.000 title claims abstract description 75
- 230000008569 process Effects 0.000 title claims abstract description 22
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 title claims abstract 17
- HGWOWDFNMKCVLG-UHFFFAOYSA-N [O--].[O--].[Ti+4].[Ti+4] Chemical compound [O--].[O--].[Ti+4].[Ti+4] HGWOWDFNMKCVLG-UHFFFAOYSA-N 0.000 title description 2
- 238000002425 crystallisation Methods 0.000 claims abstract description 160
- 239000010936 titanium Substances 0.000 claims abstract description 157
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 157
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 156
- 230000008025 crystallization Effects 0.000 claims abstract description 150
- 238000001816 cooling Methods 0.000 claims abstract description 146
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 80
- 239000004408 titanium dioxide Substances 0.000 claims abstract description 31
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 44
- 239000002253 acid Substances 0.000 claims description 13
- 238000004140 cleaning Methods 0.000 claims description 12
- 238000005406 washing Methods 0.000 claims description 12
- 239000011152 fibreglass Substances 0.000 claims description 8
- 239000002826 coolant Substances 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 239000010439 graphite Substances 0.000 claims description 4
- 229910002804 graphite Inorganic materials 0.000 claims description 4
- 229910001220 stainless steel Inorganic materials 0.000 claims description 4
- 239000010935 stainless steel Substances 0.000 claims description 4
- 238000004321 preservation Methods 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 20
- 239000013078 crystal Substances 0.000 abstract description 19
- 230000008901 benefit Effects 0.000 abstract description 12
- 239000002245 particle Substances 0.000 abstract description 6
- 238000002156 mixing Methods 0.000 abstract description 2
- 230000002349 favourable effect Effects 0.000 abstract 1
- SURQXAFEQWPFPV-UHFFFAOYSA-L iron(2+) sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Fe+2].[O-]S([O-])(=O)=O SURQXAFEQWPFPV-UHFFFAOYSA-L 0.000 description 82
- 235000010215 titanium dioxide Nutrition 0.000 description 39
- 230000005611 electricity Effects 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- 238000003756 stirring Methods 0.000 description 5
- 229920006395 saturated elastomer Polymers 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000004448 titration Methods 0.000 description 4
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 3
- 238000004134 energy conservation Methods 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- IXQWNVPHFNLUGD-UHFFFAOYSA-N iron titanium Chemical compound [Ti].[Fe] IXQWNVPHFNLUGD-UHFFFAOYSA-N 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 230000014509 gene expression Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000002910 solid waste Substances 0.000 description 2
- 238000010792 warming Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 238000005660 chlorination reaction Methods 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000008236 heating water Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- YDZQQRWRVYGNER-UHFFFAOYSA-N iron;titanium;trihydrate Chemical compound O.O.O.[Ti].[Fe] YDZQQRWRVYGNER-UHFFFAOYSA-N 0.000 description 1
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 1
- SOQBVABWOPYFQZ-UHFFFAOYSA-N oxygen(2-);titanium(4+) Chemical group [O-2].[O-2].[Ti+4] SOQBVABWOPYFQZ-UHFFFAOYSA-N 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000000844 transformation Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/14—Sulfates
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0004—Crystallisation cooling by heat exchange
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
The invention discloses a method and a device for continuously crystallizing ferrous sulfate in sulfuric acid process titanium dioxide solution, comprising the following steps: firstly, cooling the clear titanium liquid in a first-stage cooling crystallization system and a second-stage cooling crystallization system respectively in turn to crystallize ferrous sulfate in the clear titanium liquid, then mixing part of the crystallized titanium liquid with the clear titanium liquid, and then entering the first-stage cooling crystallization system and the second-stage cooling crystallization system, wherein most of the titanium liquid circulates in the first-stage cooling crystallization system and the second-stage cooling crystallization system respectively in the ferrous sulfate crystallization process, a small part of the titanium liquid flows into the next-stage working procedure, and the volume of the first-stage cooling crystallization system and the second-stage cooling crystallization system for accommodating the titanium liquid and the feeding amount of the clear titanium liquid are adjusted to realize the control of the ferrous sulfate crystallization time, so that the particle size of the ferrous sulfate crystal is favorable to be adjusted, and the method has the advantages of low cost, high production efficiency, larger particle size of the obtained ferrous sulfate crystal and low content of the obtained ferrous sulfate residual titanium.
Description
Technical Field
The invention relates to the technical field of ferrous sulfate production from sulfuric acid process titanium dioxide, in particular to a method and a device for continuously crystallizing ferrous sulfate in sulfuric acid process titanium dioxide liquid.
Background
Titanium white is used as an important chemical raw material and is widely applied to industries such as paint, plastics, printing ink and the like. At present, the titanium white production process is mainly divided into a sulfuric acid method and a chlorination method, the quality and impurity content of titanium resources, titanium white production technology and equipment and other factors are comprehensively considered, domestic titanium white enterprises mostly adopt the sulfuric acid method to produce titanium dioxide, the sulfuric acid method yield ratio is about 90%, and a sulfuric acid method titanium white manufacturer which takes whole ore as a titanium raw material uses 2.7-3.0 t of ferrous sulfate heptahydrate as a byproduct per ton of titanium white, namely ferrous sulfate for short. The titanium white production enterprises of the sulfuric acid method generally need to reduce the content of residual titanium in ferrous sulfate so as to obtain higher titanium dioxide yield and provide iron raw materials of high-quality lithium iron phosphate, so that the control of the content of residual titanium in ferrous sulfate has important economic significance.
The content of the residual titanium of ferrous sulfate is generally closely related to the granularity of ferrous sulfate crystals, the larger the granularity of the ferrous sulfate crystals is, the smaller the specific surface area of the ferrous sulfate is, and the lower the content of the residual titanium is after disc separation and centrifugation. The size of the ferrous sulfate crystallization granularity is mainly related to the crystallization stirring speed, the crystallization time and the properties of the titanium liquid, the properties of the titanium liquid are generally determined by the production process and the product characteristics of each sulfuric acid process titanium white enterprise, the crystallization time is limited by the productivity requirement of the sulfuric acid process titanium white, the crystallization stirring speed is limited by a stirring motor and the stirring effect, and the stirring speed cannot be reduced limitlessly.
The existing ferrous sulfate production process of titanium white production enterprises by a sulfuric acid method mostly adopts a steam jet vacuum crystallization method, and the method has the advantages of high technical maturity, simple process, simple operation and the like, but has the defects of intermittent operation, low production efficiency, steam consumption, fine ferrous sulfate crystallization granularity, high content of ferrous sulfate residual titanium after centrifugal separation and the like. In addition, the vacuum degree and the temperature of the crystallizer are reduced by adopting a steam jet vacuum crystallization method, and each ton of ferrous sulfate generally needs to consume 0.48t of new saturated steam, and the saturated steam is usually generated by burning coal through a boiler, so that the cost is high, and gas-solid waste is generated to pollute the environment. The steam jet vacuum crystallization method generally adopts batch operation, so that the production efficiency is low and the product quality is unstable. In a word, due to the requirements of the sulfuric acid process titanium white enterprises on productivity, equipment and other conditions, the adoption of the traditional steam jet vacuum crystallization method can lead to small ferrous sulfate crystallization granularity, high residual titanium content, low production efficiency and high production cost.
Therefore, the existing ferrous sulfate crystallization method and device are necessary to be changed, so that the purposes of reducing the content of residual titanium in ferrous sulfate, ensuring stable product quality, reducing production and operation costs and improving production efficiency are achieved.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method and a device for continuously crystallizing ferrous sulfate in titanium dioxide liquid by a sulfuric acid method, which can solve the technical problems of small ferrous sulfate crystallization granularity, high residual titanium content and low production efficiency in the existing ferrous sulfate crystallization method and device.
On the one hand, the embodiment of the invention discloses a method for continuously crystallizing ferrous sulfate in titanium dioxide liquid by a sulfuric acid method, which comprises the following steps:
flowing the clear titanium liquid into a first-stage cooling crystallization system along a first pipeline, pre-cooling the clear titanium liquid to 16-30 ℃ in the first-stage cooling crystallization system, controlling a first part of titanium liquid in the first-stage cooling crystallization system to enter a second-stage cooling crystallization system along a second pipeline, and controlling the rest titanium liquid in the first-stage cooling crystallization system to circulate in the first-stage cooling crystallization system;
the first part of titanium liquid is cooled to 16-20 ℃ in the second-stage cooling crystallization system, then the second part of titanium liquid in the second-stage cooling crystallization system is controlled to flow out along a third pipeline, the rest of titanium liquid in the second-stage cooling crystallization system is controlled to circulate in the second-stage cooling crystallization system, the part of titanium liquid in the second part of titanium liquid is controlled to flow into a disc vacuum separator along a fourth pipeline, and the other part of titanium liquid in the second part of titanium liquid continuously flows into the first pipeline along the third pipeline and is mixed with the clear titanium liquid flowing into the first pipeline;
and the mixed titanium liquid is respectively circulated in the first-stage cooling crystallization system and the second-stage cooling crystallization system in a reciprocating manner in the circulating manner.
According to one embodiment of the invention, the first cooling medium of the first cooling circulation system in the first-stage cooling crystallization system is desalted water, and the desalted water after temperature rise is sent to a metatitanic acid washing procedure; and a second cooling medium of a second cooling circulation system in the second-stage cooling crystallization system is chilled water, and the warmed chilled water enters a refrigerator to be cooled and recycled.
According to one embodiment of the invention, the volume ratio between the titanium liquid flowing into the first pipe and the second part of the titanium liquid flowing into the disc vacuum separator is controlled to be 2:13 to 1:2; the volume ratio of the second part of the titanium liquid flowing into the first pipeline to the titanium cleaning liquid flowing into the first pipeline is controlled to be 1:4-1:2.
According to one embodiment of the invention, the feeding amount of the titanium cleaning liquid is adjusted, and the average residence time of the titanium cleaning liquid entering the first-stage cooling crystallization system and the second-stage cooling crystallization system is respectively controlled to be 10-15 h.
According to one embodiment of the invention, the temperature of the desalted water fed into the first cooling circulation system is 16-30 ℃.
According to one embodiment of the invention, the chilled water fed to the second cooling circulation system has a temperature of 4-10 ℃.
On the other hand, the embodiment of the invention also discloses a device for continuously crystallizing ferrous sulfate in the titanium dioxide liquid by the sulfuric acid method, which comprises the following steps:
the first-stage cooling crystallization system is communicated with the titanium cleaning liquid feed inlet through a first pipeline and is provided with a first cooling circulation system and a first circulation pump;
the second-stage cooling crystallization system is communicated with the first-stage cooling crystallization system through a second pipeline, the second-stage cooling crystallization system is communicated with the first pipeline through a third pipeline, and a second cooling circulation system and a second circulation pump are arranged in the second-stage cooling crystallization system;
and the fourth pipeline is communicated with the third pipeline and is communicated with the disc vacuum separator.
According to one embodiment of the invention, the first-stage cooling crystallization system comprises a first heat exchanger and a first crystallization tank which are communicated through a fifth pipeline and a sixth pipeline, wherein the sixth pipeline is provided with the first circulating pump, the first heat exchanger is connected with the first cooling circulation system, and the sixth pipeline is communicated with the first pipeline;
the second-stage cooling crystallization system comprises a second heat exchanger and a second crystallization tank which are communicated through a seventh pipeline and an eighth pipeline, the eighth pipeline is provided with a second circulating pump, the second heat exchanger is connected with a second cooling circulation system, and the eighth pipeline is communicated with the second pipeline.
According to one embodiment of the invention, the first heat exchanger and the second heat exchanger are both graphite tube heat exchangers.
According to an embodiment of the present invention, the materials of the first pipe, the second pipe, the third pipe, the fourth pipe, the fifth pipe, the sixth pipe, the seventh pipe and the eighth pipe are all stainless steel with glass fiber reinforced plastic lining.
According to one embodiment of the invention, the first crystallization tank and the second crystallization tank are made of glass fiber reinforced plastic, and heat insulation layers are arranged outside the first crystallization tank and the second crystallization tank.
By adopting the technical scheme, the invention has at least the following beneficial effects:
according to the method and the device for continuously crystallizing ferrous sulfate in the titanium white liquid by the sulfuric acid method, firstly, the clear titanium liquid is sequentially cooled in the first-stage cooling crystallization system and the second-stage cooling crystallization system, so that ferrous sulfate in the clear titanium liquid is crystallized, then part of the crystallized titanium liquid is mixed with the clear titanium liquid and then enters the first-stage cooling crystallization system and the second-stage cooling crystallization system, ferrous sulfate precipitated in the titanium liquid can preferentially grow on the introduced ferrous sulfate crystals, new crystal nuclei are prevented from being generated, and the ferrous sulfate crystals with large granularity are facilitated to be obtained. In the process of ferrous sulfate crystallization, most of titanium liquid circulates in a first-stage cooling crystallization system and a second-stage cooling crystallization system respectively, a small part of titanium liquid is controlled to flow into the next-stage working procedure, and the particle size of ferrous sulfate crystals is favorably adjusted by adjusting the volume of the first-stage cooling crystallization system and the second-stage cooling crystallization system for accommodating the titanium liquid and adjusting the feeding amount of the titanium cleaning liquid so as to realize control over ferrous sulfate crystallization time.
Therefore, the method and the device for continuously crystallizing ferrous sulfate in the sulfuric acid process titanium dioxide solution improve the production efficiency, reduce the granularity of ferrous sulfate crystals, reduce the content of residual titanium ferrous sulfate and ensure the quality stability of the obtained product.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of an apparatus for continuously crystallizing ferrous sulfate in titanium dioxide liquid by sulfuric acid process according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following embodiments of the present invention will be described in further detail with reference to the accompanying drawings.
It should be noted that, in the embodiments of the present invention, all the expressions "first" and "second" are used to distinguish two entities with the same name but different entities or different parameters, and it is noted that the "first" and "second" are only used for convenience of expression, and should not be construed as limiting the embodiments of the present invention, and the following embodiments are not described one by one.
In one aspect, an embodiment of the invention discloses a method for continuously crystallizing ferrous sulfate in titanium dioxide liquid by a sulfuric acid method, which comprises the following steps:
flowing the clear titanium liquid into a first-stage cooling crystallization system along a first pipeline, pre-cooling the clear titanium liquid to 16-30 ℃ in the first-stage cooling crystallization system, controlling a first part of titanium liquid in the first-stage cooling crystallization system to enter a second-stage cooling crystallization system along a second pipeline, and controlling the rest titanium liquid in the first-stage cooling crystallization system to circulate in the first-stage cooling crystallization system;
cooling the first part of titanium liquid to 16-20 ℃ in a second-stage cooling crystallization system, controlling the second part of titanium liquid in the second-stage cooling crystallization system to flow out along a third pipeline, controlling the rest of titanium liquid in the second-stage cooling crystallization system to circulate in the second-stage cooling crystallization system, controlling part of titanium liquid in the second part of titanium liquid to flow into a disc vacuum separator along a fourth pipeline, and continuously flowing the other part of titanium liquid in the second part of titanium liquid into the first pipeline along the third pipeline and mixing with the clear titanium liquid flowing into the first pipeline;
the mixed titanium liquid is respectively circulated in the first-stage cooling crystallization system and the second-stage cooling crystallization system in a reciprocating manner in the circulating manner.
In the present invention, the clear titanium solution is a clear titanium solution obtained by settling after acidolysis of ilmenite in industrial production. The titanium liquid mentioned in the embodiment of the invention refers to clear titanium liquid and/or mixed titanium liquid.
In some embodiments of the present invention, the first cooling medium of the first cooling circulation system in the first stage cooling crystallization system is desalted water, and the desalted water after temperature rise is sent to the metatitanic acid washing procedure; the second cooling medium of the second cooling circulation system in the second-stage cooling crystallization system is chilled water, and the warmed chilled water enters a refrigerator for cooling and recycling. The titanium liquid is cooled and lowered into two stages, the desalted water is utilized to cool the titanium liquid in the first stage, the desalted water after temperature rise can be directly used as the water for washing the metatitanic acid, steam for heating the water for washing the metatitanic acid can be saved, and in the second stage, in order to cool the titanium liquid to the temperature meeting the control requirement of the titanium liquid on the iron-titanium ratio, chilled water is utilized to exchange heat and cool, and the chilled water returns to a refrigerator to be cooled and recycled after heat exchange, so that the purposes of energy conservation and consumption reduction are realized. The method and the device for continuously crystallizing ferrous sulfate in the sulfuric acid process titanium dioxide solution have the advantages of low production cost and operation cost and high production efficiency.
In some embodiments of the invention, the volume ratio between the titanium liquid flowing into the first conduit and the second portion flowing into the disc vacuum separator, respectively, is controlled to be 2:13 to 1:2; the volume ratio of the second part of the titanium liquid flowing into the first pipeline to the clear titanium liquid flowing into the first pipeline is controlled to be 1:4-1:2.
In some embodiments of the invention, the feeding amount of the titanium cleaning liquid is adjusted, and the average residence time of the titanium cleaning liquid entering the first-stage cooling crystallization system and the second-stage cooling crystallization system is respectively controlled to be 10-15 h.
In some embodiments of the invention, the temperature of the desalted water fed to the first cooling circulation system is 16 to 30 ℃. Specifically, the temperature of desalted water introduced in different seasons is different, the temperature of the titanium cleaning solution and/or the temperature of the mixed titanium solution after reduction is different according to the temperature of the desalted water, for example, in spring and autumn, the temperature of the desalted water at room temperature can reduce the temperature of the titanium feeding solution to 18-25 ℃; the desalted water in winter has low temperature, and can cool the feeding titanium liquid to 16-20 ℃; the temperature of desalted water in summer is high, and the temperature of the titanium liquid to be fed can be reduced to 25-30 ℃. In addition, the desalted water can cool the titanium liquid to 16-20 ℃ in winter, at the moment, the temperature of the titanium liquid meets the control requirement of the titanium liquid on the iron-titanium ratio, the second cooling circulation system can not be started, and only the titanium liquid after the titanium liquid is cleaned and/or mixed is circulated in the second cooling crystallization system, so that the electric energy consumed by cooling water cooling refrigeration is saved, and the energy conservation and consumption reduction are realized.
In some embodiments of the invention, the chilled water introduced into the second cooling circulation system has a temperature of 4 ℃ to 10 ℃.
In another aspect, as shown in fig. 1, an embodiment of the present invention discloses an apparatus for continuously crystallizing ferrous sulfate in a titanium dioxide solution by sulfuric acid process, which comprises:
the first-stage cooling crystallization system 100, wherein the first-stage cooling crystallization system 100 is communicated with a titanium cleaning liquid feed inlet through a first pipeline 300, and the first-stage cooling crystallization system 100 is provided with a first cooling circulation system 110 and a first circulation pump 120;
the second-stage cooling crystallization system 200, the second-stage cooling crystallization system 200 is communicated with the first-stage cooling crystallization system 100 through a second pipeline 400, the second-stage cooling crystallization system 200 is communicated with the first pipeline 300 through a third pipeline 500, and a second cooling circulation system 210 and a second circulation pump 220 are arranged in the second-stage cooling crystallization system 200;
a fourth pipe 600, the fourth pipe 600 communicating with the third pipe 500, the fourth pipe 600 communicating with the disk vacuum separator 700.
The disc vacuum separator 700 is used to separate the titanium liquid and the ferrous sulfate crystals, and in some embodiments, the ferrous sulfate crystals separated by the disc vacuum separator 700 may be sent to the centrifuge 800 for further centrifugation.
In some embodiments of the present invention, the first stage cooling crystallization 100 system includes a first heat exchanger 130 and a first crystallization tank 140 that are connected through a fifth pipe 160 and a sixth pipe 170, the sixth pipe 170 is provided with a first circulation pump 120, the first heat exchanger 130 is connected with a first cooling circulation system 110, and the sixth pipe 170 is connected with a first pipe 300;
the second-stage cooling crystallization system 200 comprises a second heat exchanger 230 and a second crystallization tank 240 which are communicated through a seventh pipeline 260 and an eighth pipeline 270, wherein a second circulating pump 220 is arranged on the eighth pipeline 270, the second heat exchanger 230 is connected with a second cooling circulation system 210, and the eighth pipeline 270 is communicated with the second pipeline 400.
In some embodiments of the invention, both the first heat exchanger 130 and the second heat exchanger 230 are graphite tube-in-tube heat exchangers. The graphite tube heat exchanger has the advantages of high heat conductivity and corrosion resistance.
In some embodiments of the present invention, the first pipe 300, the second pipe 400, the third pipe 500, the fourth pipe 600, the fifth pipe 160, the sixth pipe 170, the seventh pipe 260, and the eighth pipe 270 are all stainless steel with glass fiber reinforced plastic lining. Stainless steel with glass fiber reinforced plastic lining has the advantage of acid resistance.
In some embodiments of the present invention, the materials of the first crystallization tank 140 and the second crystallization tank 240 are glass fiber reinforced plastics, and the heat insulation layers are disposed outside the first crystallization tank 140 and the second crystallization tank 240. The glass fiber reinforced plastic has the advantage of acid resistance. The heat preservation layers are arranged outside the first crystallization tank 140 and the second crystallization tank 240, so that heat exchange between the titanium liquid in the first crystallization tank and the titanium liquid in the second crystallization tank and the outside can be avoided, and the stability of the temperature of the titanium liquid in the first crystallization tank and the temperature of the titanium liquid in the second crystallization tank can be guaranteed.
Compared with the traditional steam jet vacuum crystallization method, the method for continuously crystallizing ferrous sulfate in titanium white liquid by using sulfuric acid method provided by the embodiment of the invention has the advantages that the crystallization time is long, the crystal seeds are introduced, the crystal granularity of ferrous sulfate is increased, the residual titanium content is reduced, the titanium liquid is subjected to first-step cooling through desalted water, then the part of desalted water after heating is sent to a metatitanic acid washing process, the steam consumption for heating water for metatitanic acid washing is saved, the titanium liquid is subjected to second-step cooling through chilled water, the temperature of the titanium liquid is reduced to the low temperature required by control, the warmed chilled water is cooled through a refrigerator and recycled, no solid waste is generated in the whole process, and the method is economical and environment-friendly.
By using the ferrous sulfate continuous crystallization method disclosed by the embodiment of the invention, the content of residual titanium ferrous sulfate can be reduced from 0.36% to 0.10%, the steam consumption of each ton of ferrous sulfate can be reduced from 0.48t to-0.2 t (the negative value represents the steam consumption for heating the water for washing the meta-titanic acid, which is saved by washing the meta-titanic acid with desalted water after heating), the electricity consumption of each ton of ferrous sulfate is increased from 133kwh to 220kwh, wherein the price of saturated steam is 250 yuan/t, the unit price of titanium dioxide in the ferrous sulfate is 7000 yuan/t, the unit price of electricity is 0.5 yuan/kwh, 2.8t of ferrous is generated per ton of titanium white, and the price of residual titanium dioxide in the ferrous is 7000 yuan/t. If the annual yield of titanium dioxide by sulfuric acid method is 23.5t, the economic benefit generated thereby is = (yield improvement is ferrous residual titanium price + steam consumption reduction value is steam price-electricity consumption unit price) annual yield of titanium dioxide = [ (0.36% -0.1%) ×2.8×7000+ (0.48+0.2) ×2.8×250- (220-133) ×2.8×0.5] ×23.5= 9521.26 ten thousand yuan.
The following is a detailed description of comparative example 1 and examples 2 to 4:
comparative example 1
The crystallization is carried out according to the traditional steam jet vacuum crystallization method, the steam consumption and the electricity consumption of each ton of ferrous sulfate are counted, the ferrous sulfate separated by a disc vacuum separator is taken, and the granularity and the residual titanium content of the ferrous sulfate are measured by an electron microscope and a chemical titration method respectively and are recorded in the following table 1.
Example 2
According to the method and the device for continuously crystallizing ferrous sulfate in titanium white liquid by a sulfuric acid method, which are provided by the embodiment of the invention, titanium liquid cooling crystallization is carried out, the feeding amount of the titanium liquid is adjusted, so that the average residence time of the titanium liquid in a first-stage cooling crystallization system and a second-stage cooling crystallization system is 10h, the feeding volume ratio of the second part of the titanium liquid flowing into a first pipeline after cooling to the feeding clear titanium liquid is 1:4, the electricity consumption and the saved steam consumption of each ton of ferrous sulfate are counted, the ferrous sulfate separated by a disc vacuum separator is taken, and the granularity and the residual titanium content of the ferrous sulfate are measured by an electron microscope and a chemical titration method respectively and are recorded in the following table 1.
Example 3
According to the method and the device for continuously crystallizing ferrous sulfate in titanium white liquid by a sulfuric acid method, which are provided by the embodiment of the invention, titanium liquid is subjected to cooling crystallization, the feeding amount of the titanium liquid is adjusted, so that the average residence time of the titanium liquid in a first-stage cooling crystallization system and a second-stage cooling system is 15h, the feeding volume ratio of the second part of titanium liquid flowing into a first pipeline after cooling to the feeding clear titanium liquid is 1:4, the electricity consumption and the saved steam consumption of each ton of ferrous sulfate are counted, the ferrous sulfate separated by a disc vacuum separator is taken, and the granularity and the residual titanium content of the ferrous sulfate are measured by an electron microscope and a chemical titration method respectively and are recorded in the following table 1.
Example 4
According to the method and the device for continuously crystallizing ferrous sulfate in titanium white liquid by a sulfuric acid method, which are provided by the embodiment of the invention, titanium liquid is subjected to cooling crystallization, the feeding amount of the titanium liquid is adjusted, so that the average residence time of the titanium liquid in a first-stage cooling crystallization system and a second-stage cooling system is 15h, the feeding volume ratio of the second part of titanium liquid flowing into a first pipeline after cooling to the feeding clear titanium liquid is 1:2, the electricity consumption and the saved steam consumption of each ton of ferrous sulfate are counted, the ferrous sulfate separated by a disc vacuum separator is taken, and the granularity and the residual titanium content of the ferrous sulfate are measured by an electron microscope and a chemical titration method respectively and are recorded in the following table 1.
The cost per ton of titanium dioxide savings in examples 2 to 4 was calculated as "cost per ton of titanium dioxide = increase in yield =price of titanium dioxide residue + decrease in steam consumption =price of steam-electricity consumption × unit price of electricity", and is shown in table 1 below.
Table 1 statistics and calculation results of comparative example 1 and examples 2 to 4
In the above table, the ferrous sulfate particle size is characterized by the long diameter, i.e., the longest diameter; steam here refers to saturated steam, the steam temperature is 160 ℃, and the steam price is 250 yuan/t; electricity price 0.5 yuan/kwh; the cost of residual titanium is 7000 yuan/t; negative values represent the steam consumption for warming the water for the metatitanic acid wash that is saved by washing the metatitanic acid with the desalted water after warming.
Compared with the traditional steam jet vacuum crystallization method, the method and the device for continuously crystallizing ferrous sulfate in titanium dioxide liquid by a sulfuric acid method provided by the embodiment of the invention have the advantages that the granularity of the obtained ferrous sulfate is larger, the content of residual ferrous sulfate titanium is lower, the steam consumption is lower, and the electricity consumption is increased, but the comprehensive calculation is carried out, and the cost saved per ton of titanium dioxide is 370.72-405.16 yuan; as can be seen from comparative examples 2 and 3, the titanium solution is increased in the first-stage cooling crystallization system and the second-stage cooling crystallization system, the crystallization granularity of ferrous sulfate is larger, and the content of residual titanium ferrous sulfate separated by the disc vacuum separator is lower; comparative examples 3 and 4 show that, after the addition of the ferrous sulfate seed crystal was increased, the particle size of ferrous sulfate separated by the disc vacuum separator was decreased and the residual titanium content was increased.
In summary, according to the method and the device for continuously crystallizing ferrous sulfate in titanium white liquid by a sulfuric acid method provided by the embodiment of the invention, firstly, the clear titanium liquid is sequentially cooled in the first-stage cooling crystallization system and the second-stage cooling crystallization system, so that ferrous sulfate in the clear titanium liquid is crystallized, then part of crystallized titanium liquid is mixed with the clear titanium liquid and then enters the first-stage cooling crystallization system and the second-stage cooling crystallization system, ferrous sulfate precipitated in the titanium liquid preferentially grows on the introduced ferrous sulfate crystals, new crystal nuclei are prevented from being generated, and the ferrous sulfate crystals with large granularity are obtained.
In the process of ferrous sulfate crystallization, most of titanium liquid circulates in a first-stage cooling crystallization system and a second-stage cooling crystallization system respectively, a small part of titanium liquid is controlled to flow into the next-stage working procedure, and the particle size of ferrous sulfate crystals is favorably adjusted by adjusting the volume of the first-stage cooling crystallization system and the second-stage cooling crystallization system for accommodating the titanium liquid and adjusting the feeding amount of the titanium cleaning liquid so as to realize control over ferrous sulfate crystallization time.
In addition, the titanium liquid is cooled and divided into two stages, the desalted water is utilized to cool the titanium liquid in the first stage, the desalted water after temperature rise can be directly used as the water for washing the metatitanic acid, steam for heating the water for washing the metatitanic acid can be saved, and in the second stage, in order to cool the titanium liquid to the temperature meeting the control requirement of the titanium liquid on the iron-titanium ratio, chilled water is utilized to exchange heat and cool, and the chilled water returns to a refrigerator to be cooled and recycled after heat exchange, so that the purposes of energy conservation and consumption reduction are realized.
Therefore, the method and the device for continuously crystallizing ferrous sulfate in the sulfuric acid process titanium dioxide solution have the advantages of low production cost, high production efficiency, larger granularity of the obtained ferrous sulfate crystal, low content of the obtained ferrous sulfate residual titanium and stable quality of the obtained product.
It should be noted that, each component or step in each embodiment may be intersected, replaced, added, and deleted, and therefore, the combination formed by these reasonable permutation and combination transformations shall also belong to the protection scope of the present invention, and shall not limit the protection scope of the present invention to the embodiments.
The foregoing is an exemplary embodiment of the present disclosure, and the order in which the embodiments of the present disclosure are disclosed is merely for the purpose of description and does not represent the advantages or disadvantages of the embodiments. It should be noted that the above discussion of any of the embodiments is merely exemplary and is not intended to suggest that the scope of the disclosure of embodiments of the invention (including the claims) is limited to these examples and that various changes and modifications may be made without departing from the scope of the invention as defined in the claims. The functions, steps and/or actions of the method claims in accordance with the disclosed embodiments described herein need not be performed in any particular order. Furthermore, although elements of the disclosed embodiments may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.
Those of ordinary skill in the art will appreciate that: the above discussion of any embodiment is merely exemplary and is not intended to imply that the scope of the disclosure of embodiments of the invention, including the claims, is limited to such examples; combinations of features of the above embodiments or in different embodiments are also possible within the idea of an embodiment of the invention, and there are many other variations of the different aspects of the embodiments of the invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, and the like, which are made within the spirit and principles of the embodiments of the invention, are included within the scope of the embodiments of the invention.
Claims (9)
1. A method for continuously crystallizing ferrous sulfate in titanium dioxide liquid by a sulfuric acid method is characterized by comprising the following steps:
flowing the clear titanium liquid into a first-stage cooling crystallization system along a first pipeline, pre-cooling the clear titanium liquid to 16-30 ℃ in the first-stage cooling crystallization system, controlling a first part of titanium liquid in the first-stage cooling crystallization system to enter a second-stage cooling crystallization system along a second pipeline, and controlling the rest titanium liquid in the first-stage cooling crystallization system to circulate in the first-stage cooling crystallization system;
the first part of titanium liquid is cooled to 16-20 ℃ in the second-stage cooling crystallization system, then the second part of titanium liquid in the second-stage cooling crystallization system is controlled to flow out along a third pipeline, the rest of titanium liquid in the second-stage cooling crystallization system is controlled to circulate in the second-stage cooling crystallization system, the part of titanium liquid in the second part of titanium liquid is controlled to flow into a disc vacuum separator along a fourth pipeline, and the other part of titanium liquid in the second part of titanium liquid continuously flows into the first pipeline along the third pipeline and is mixed with the clear titanium liquid flowing into the first pipeline;
and the mixed titanium liquid is respectively circulated in the first-stage cooling crystallization system and the second-stage cooling crystallization system in a reciprocating manner in the circulating manner.
2. The method for continuously crystallizing ferrous sulfate in titanium dioxide liquid by sulfuric acid method according to claim 1, wherein a first cooling medium of a first cooling circulation system in the first-stage cooling crystallization system is desalted water, and the desalted water after heating is sent to a metatitanic acid washing process; and a second cooling medium of a second cooling circulation system in the second-stage cooling crystallization system is chilled water, and the warmed chilled water enters a refrigerator to be cooled and recycled.
3. The method for continuous crystallization of ferrous sulfate in titanium dioxide liquid according to claim 1, wherein the volume ratio between the titanium liquid flowing into the first pipe and the second part flowing into the disc vacuum separator is controlled to be 2:13 to 1:2; the volume ratio of the second part of the titanium liquid flowing into the first pipeline to the titanium cleaning liquid flowing into the first pipeline is controlled to be 1:4-1:2.
4. The method for continuously crystallizing ferrous sulfate in titanium dioxide liquid by a sulfuric acid process according to claim 1, wherein the feeding amount of the clear titanium liquid is adjusted, and the average residence time of the titanium liquid entering the first-stage cooling crystallization system and the second-stage cooling crystallization system is controlled to be 10-15 h respectively.
5. The method for continuously crystallizing ferrous sulfate in titanium dioxide liquid by sulfuric acid process as claimed in claim 2, wherein the temperature of the desalted water introduced into the first cooling circulation system is 16-30 ℃; the temperature of the chilled water introduced into the second cooling circulation system is 4-10 ℃.
6. The device for continuously crystallizing ferrous sulfate in titanium dioxide liquid by a sulfuric acid method is characterized by comprising:
the first-stage cooling crystallization system is communicated with a titanium cleaning liquid feed inlet through a first pipeline, the first-stage cooling crystallization system is provided with a first cooling circulation system and a first circulating pump, the first-stage cooling crystallization system comprises a first heat exchanger and a first crystallization tank which are communicated through a fifth pipeline and a sixth pipeline, the sixth pipeline is provided with the first circulating pump, the first heat exchanger is connected with the first cooling circulation system, and the sixth pipeline is communicated with the first pipeline;
the second-stage cooling crystallization system is communicated with the first-stage cooling crystallization system through a second pipeline, the second-stage cooling crystallization system is communicated with the first pipeline through a third pipeline, a second cooling circulation system and a second circulation pump are arranged in the second-stage cooling crystallization system, the second-stage cooling crystallization system comprises a second heat exchanger and a second crystallization tank which are communicated through a seventh pipeline and an eighth pipeline, the second circulation pump is arranged on the eighth pipeline, the second cooling circulation system is connected to the second heat exchanger, and the eighth pipeline is communicated with the second pipeline;
and the fourth pipeline is communicated with the third pipeline and is communicated with the disc vacuum separator.
7. The apparatus for continuous crystallization of ferrous sulfate in titanium dioxide liquid according to claim 6, wherein the first heat exchanger and the second heat exchanger are graphite tube heat exchangers.
8. The device for continuously crystallizing ferrous sulfate in titanium dioxide liquid by sulfuric acid process as claimed in claim 6, wherein the first pipeline, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, the sixth pipeline, the seventh pipeline and the eighth pipeline are all made of stainless steel with glass fiber reinforced plastic lining.
9. The device for continuously crystallizing ferrous sulfate in titanium dioxide liquid by sulfuric acid process as claimed in claim 6, wherein the first crystallization tank and the second crystallization tank are made of glass fiber reinforced plastics, and heat preservation layers are arranged outside the first crystallization tank and the second crystallization tank.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108726578A (en) * | 2018-06-27 | 2018-11-02 | 安徽帝瑟化工科技工程有限公司 | Ferrous sulfate continuous crystallisation technique in a kind of production of sulfate process titanium dioxide |
| CN112357966A (en) * | 2020-11-04 | 2021-02-12 | 成都千砺金科技创新有限公司 | Crystallization method of ferrous sulfate heptahydrate in production process of titanium dioxide by sulfuric acid method |
| CN112499676A (en) * | 2020-12-04 | 2021-03-16 | 南通三圣石墨设备科技股份有限公司 | Intermittent vacuum crystallization ferrous sulfate process and preparation system |
| CN215137034U (en) * | 2021-01-07 | 2021-12-14 | 河北乐恒节能设备有限公司 | Glauber's salt serialization cooling crystallization equipment |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108726578A (en) * | 2018-06-27 | 2018-11-02 | 安徽帝瑟化工科技工程有限公司 | Ferrous sulfate continuous crystallisation technique in a kind of production of sulfate process titanium dioxide |
| CN112357966A (en) * | 2020-11-04 | 2021-02-12 | 成都千砺金科技创新有限公司 | Crystallization method of ferrous sulfate heptahydrate in production process of titanium dioxide by sulfuric acid method |
| CN112499676A (en) * | 2020-12-04 | 2021-03-16 | 南通三圣石墨设备科技股份有限公司 | Intermittent vacuum crystallization ferrous sulfate process and preparation system |
| CN215137034U (en) * | 2021-01-07 | 2021-12-14 | 河北乐恒节能设备有限公司 | Glauber's salt serialization cooling crystallization equipment |
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Effective date of registration: 20231206 Address after: 617000 Taoyuan street, East District, Panzhihua, Sichuan Province, No. 90 Patentee after: PANGANG GROUP PANZHIHUA IRON & STEEL RESEARCH INSTITUTE Co.,Ltd. Patentee after: PANGANG GROUP VANADIUM TITANIUM & RESOURCES Co.,Ltd. Address before: 617000 Taoyuan street, East District, Panzhihua, Sichuan Province, No. 90 Patentee before: PANGANG GROUP PANZHIHUA IRON & STEEL RESEARCH INSTITUTE Co.,Ltd. |