CN113461048A - Titanium dioxide acidolysis titanium liquid purification and reduction method and system by sulfuric acid process - Google Patents
Titanium dioxide acidolysis titanium liquid purification and reduction method and system by sulfuric acid process Download PDFInfo
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- 239000010936 titanium Substances 0.000 title claims abstract description 207
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 title claims abstract description 194
- 229910052719 titanium Inorganic materials 0.000 title claims abstract description 194
- 239000007788 liquid Substances 0.000 title claims abstract description 130
- 238000000034 method Methods 0.000 title claims abstract description 69
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 title claims abstract description 63
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims abstract description 55
- 230000009467 reduction Effects 0.000 title claims abstract description 45
- 230000008569 process Effects 0.000 title claims abstract description 27
- 239000004408 titanium dioxide Substances 0.000 title claims abstract description 25
- 238000000746 purification Methods 0.000 title claims abstract description 10
- 239000002002 slurry Substances 0.000 claims abstract description 32
- 238000003860 storage Methods 0.000 claims abstract description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 19
- 239000000243 solution Substances 0.000 claims description 62
- 238000006460 hydrolysis reaction Methods 0.000 claims description 24
- 239000000463 material Substances 0.000 claims description 23
- 238000001816 cooling Methods 0.000 claims description 21
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical group [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 14
- 238000006243 chemical reaction Methods 0.000 claims description 11
- 239000008394 flocculating agent Substances 0.000 claims description 10
- 238000001914 filtration Methods 0.000 claims description 8
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 claims description 8
- 239000006228 supernatant Substances 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 5
- 230000005540 biological transmission Effects 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 4
- 238000011946 reduction process Methods 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- 238000003487 electrochemical reaction Methods 0.000 claims description 3
- 239000000706 filtrate Substances 0.000 claims description 3
- 229910002804 graphite Inorganic materials 0.000 claims description 3
- 239000010439 graphite Substances 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 3
- 239000011259 mixed solution Substances 0.000 claims description 3
- 238000010992 reflux Methods 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 2
- 229910052760 oxygen Inorganic materials 0.000 claims description 2
- 239000001301 oxygen Substances 0.000 claims description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 39
- 238000004519 manufacturing process Methods 0.000 abstract description 17
- 229910000359 iron(II) sulfate Inorganic materials 0.000 abstract description 8
- 239000002699 waste material Substances 0.000 abstract description 8
- 239000002253 acid Substances 0.000 abstract description 6
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 abstract description 6
- 230000007613 environmental effect Effects 0.000 abstract description 2
- 239000002912 waste gas Substances 0.000 abstract description 2
- 235000003891 ferrous sulphate Nutrition 0.000 abstract 1
- 239000011790 ferrous sulphate Substances 0.000 abstract 1
- 239000002994 raw material Substances 0.000 abstract 1
- 238000000926 separation method Methods 0.000 abstract 1
- 235000010215 titanium dioxide Nutrition 0.000 description 17
- 229920005549 butyl rubber Polymers 0.000 description 8
- 230000007062 hydrolysis Effects 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 4
- 239000010410 layer Substances 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000000956 alloy Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000012141 concentrate Substances 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000004062 sedimentation Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000011473 acid brick Substances 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 229920006351 engineering plastic Polymers 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000007770 graphite material Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 229910052603 melanterite Inorganic materials 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000011112 process operation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G23/00—Compounds of titanium
- C01G23/04—Oxides; Hydroxides
- C01G23/047—Titanium dioxide
- C01G23/053—Producing by wet processes, e.g. hydrolysing titanium salts
- C01G23/0532—Producing by wet processes, e.g. hydrolysing titanium salts by hydrolysing sulfate-containing salts
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Electrolytic Production Of Metals (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
Abstract
The invention belongs to the technical field of titanium dioxide production by a sulfuric acid method, and particularly relates to a titanium dioxide acidolysis titanium liquid purification and reduction method and a titanium dioxide acidolysis titanium liquid purification and reduction system by the sulfuric acid method, which comprise a titanium acidolysis liquid cooler, a settling tank, a slurry plate-and-frame filter press, a dilute titanium liquid storage tank, a tubular filter, a clear titanium liquid storage tank, an electrolytic tank, a reduced titanium liquid tank, a circulating pump, a reduced titanium liquid cooler, an online analyzer and a control valve, wherein the method changes the reduction sequence and the reduction mode of Fe3+ and Ti4+ in titanium liquid in the prior art, adopts a process of firstly carrying out heat exchange purification and then carrying out electrolytic reduction, saves a large amount of iron powder and sulfuric acid raw materials, greatly reduces the consumption of a large amount of cold and heat due to the separation of ferrous sulfate in the subsequent flow, simultaneously reduces the discharge of low-value FeSO 4.7H2O and FeSO 4.H2O, greatly reduces the discharge of waste gas and waste acid water, reduces the labor intensity, improves the labor environment, and the titanium liquid acidolysis section can realize automatic and accurate reduction, and clean production with resource conservation and environmental friendliness is realized.
Description
Technical Field
The invention belongs to the technical field of sulfuric acid process titanium dioxide production, and particularly relates to a method and a system for purifying and reducing titanium dioxide acidolysis solution of sulfuric acid process titanium dioxide.
Background
At present, the domestic titanium dioxide production technology mainly adopts a sulfuric acid method, the annual capacity of the sulfuric acid method is over 300 ten thousand tons, and a plurality of production devices are built and operated by domestic utilization of the technology. In consideration of production cost, most manufacturers adopt titanium concentrate with TiO2 content of 44-50%, wherein the contents of Fe2O3 and FeO are high, titanium liquid after acidolysis by sulfuric acid contains more Fe2(SO4)3 and FeSO4, in the acidolysis reaction process, because compressed air is adopted for stirring, the FeSO4 part is oxidized into Fe2(SO4)3 at high temperature, and if the Fe3+ is not removed, the hue of the product is seriously influenced, SO that qualified titanium dioxide cannot be produced.
At present, iron powder is added into an acidolysis tank or a reduction tank to reduce all Fe3+ into Fe2+ in China, so that part of Fe2+ is oxidized into Fe3+ by air in the subsequent process operation, and the iron powder is in proper excess to ensure that the concentration of Ti3+ in the titanium liquid reaches 1.5-3 g/L.
From the reflection data of most manufacturers, about 155kg of iron powder is averagely consumed by titanium white in a sulfuric acid process per ton, calculated by 10 million tons of titanium dioxide produced annually, 15500 tons of iron powder is consumed annually, the cost reaches about 0.53 hundred million yuan, the iron powder is finally produced in FeSO 4.7H 2O and FeSO 4. H2O types, and FeSO 4.7H 2O and FeSO 4. H2O produced by titanium concentrate acidolysis are huge in quantity and difficult to sell, and more cold and heat are required to be consumed in the process of separating FeSO4, so that the iron powder becomes a troublesome problem which is difficult to solve by manufacturers increasingly. And the new added iron powder needs to consume more sulfuric acid, generates more waste water and waste gas, and has obvious cost and environmental problems.
Disclosure of Invention
Aiming at the problems in the background art, the invention provides a method and a system for purifying and reducing titanium dioxide acidolysis liquid by a sulfuric acid method, which can reduce production energy consumption, save production time, reduce production cost and reduce environmental pollution.
The specific technical scheme is as follows:
a method for purifying and reducing titanium dioxide acidolysis titanium liquid by a sulfuric acid method comprises the following steps:
step (1): a cooling process, wherein the cooling process comprises the following steps,
introducing the titanium acidolysis solution cured in the acidolysis tank or the secondary dissolving tank into an inlet at the bottom of a titanium acidolysis solution cooler 1, introducing the dilute titanium solution filtered by a disc in a crystallization-hydrolysis section into an inlet at the side surface of the upper part of the titanium acidolysis solution cooler 1, after indirect heat exchange, raising the temperature of the dilute titanium solution from about 20 ℃ to about 55 ℃, then returning the dilute titanium solution to a feeding tank of a tubular filter in the crystallization-hydrolysis section from an outlet at the side surface of the lower part of the titanium acidolysis solution cooler 1, cooling the titanium acidolysis solution to about 60 ℃, then mixing the dilute titanium solution from the top of the titanium acidolysis solution cooler 1 with a flocculating agent in proportion, and then feeding the mixed titanium acidolysis solution and the flocculating agent into a continuous settling tank 2, wherein the mixed volume ratio of the cooled titanium acidolysis solution and the flocculating agent is 1: 0.03-1: 0.07.
Step (2): a settling working procedure is carried out,
continuously settling the mixed solution in a settling tank (2) for 2-4 hours to obtain supernatant and lower layer slurry, introducing the supernatant into a tubular filter (11) for fine filtration to obtain clear titanium solution, wherein the solid content of impurities in the clear titanium solution is lower than 10ppm, and the temperature is 50-55 ℃;
and (3): a reduction process of the acidolysis titanium solution,
introducing the clean titanium solution into the electrolytic cell 14, and switching on a direct current power supply of the electrolytic cell 14 to perform electrochemical reaction as follows:
anode: 4OH- -4e = 2H2O+O2↑
Cathode: fe3+ +e = Fe2+
Ti4+ +e = Ti3+
The general reaction formula is as follows: 2Fe2(SO4)3+2H2O= 4FeSO4+2H2SO4+O2↑
2TiOSO4 +H2SO4= Ti2(SO4)3+H2O
The electrolytic reaction temperature in the electrolytic cell 14 is 60-75 ℃ to obtain the Fe-containing alloy2+And Ti3+Reducing the titanium solution;
and (4): a cooling process, wherein the cooling process comprises the following steps,
introducing reduced titanium liquid into the bottom of the reduced titanium liquid cooler 17, cooling the reduced titanium liquid to 40-45 ℃ by circulating water, refluxing the cooled reduced titanium liquid into the electrolytic bath 14, and analyzing Ti in the cooled reduced titanium liquid by the online analyzer 183+In an amount of Ti3+When the content is 1.5-3 g/L, opening the control valve 19 in an interlocking manner to discharge part of the cooled reduced titanium liquid, and conveying the part to a ferrous crystallizer of a downstream crystallization-hydrolysis section through a pipeline, wherein the total titanium content of the reduced titanium liquid is as follows: 120-135 g/L, F value: 1.7-1.9, trivalent titanium: 1.5-3 g/L, stability: not less than 300.
Further, the operation pressure of the titanium reduction liquid in the step (4) is higher than the operation pressure of the circulating water.
The invention also comprises a system of the sulfuric acid method titanium dioxide acidolysis titanium liquid purification reduction method,
comprises an acidolysis titanium liquid cooler 1, a settling tank 2, a slurry tank 4, a plate-and-frame filter press 6, a dilute titanium liquid storage tank 9, an electrolytic tank 14, a reduced titanium liquid tank 15 and a reduced titanium liquid cooler 17; the top of the electrolytic cell 14 is communicated with an oxygen vent pipe;
the hot material inlet at the bottom of the titanium acidolysis liquid cooler 1 is communicated with an acidolysis tank or a secondary dissolving tank through a pipeline, the cold material inlet at the upper part of the titanium acidolysis liquid cooler 1 is communicated with a dilute titanium liquid storage tank after being filtered by a crystallization-hydrolysis workshop section disc through a pipeline, the cold material outlet at the lower part of the titanium acidolysis liquid cooler 1 is communicated with a tubular filter feeding tank at the crystallization-hydrolysis workshop section through a pipeline, the hot material outlet at the top of the titanium acidolysis liquid cooler 1 is communicated with a central cylinder inlet of the settling tank 2 through an outlet pipe, and a flocculating agent feeding pipe is communicated with the outlet pipe;
the bottom outlet of the settling tank 2 is communicated with the top inlet of a slurry tank 4 through a slurry pump 3 pipeline, the lower outlet of the slurry tank 4 is communicated with the feed inlet of a plate-and-frame filter press 6 through a plate-and-frame feed pump 5 pipeline, the filtrate outlet of the plate-and-frame filter press 6 is communicated with the central cylinder inlet of the settling tank 2 through a pipeline, the upper overflow port of the settling tank 2 is communicated with the top inlet of a dilute titanium liquid storage tank 9 through a pipeline, the bottom outlet of the dilute titanium liquid storage tank 9 is communicated with the lower feed inlet of a tubular filter 11 through a feed pump 10, the upper discharge port pipeline of the tubular filter 11 is communicated with the top feed inlet of a clean titanium liquid storage tank 12, the bottom slurry outlet pipeline of the tubular filter 11 is communicated with the top inlet of the slurry tank 4, the lower outlet of the clean titanium liquid storage tank 12 is communicated with the top inlet of an electrolytic tank (14) through an electrolytic tank feed pump 13 pipeline, the bottom outlet pipeline of the electrolytic tank 14 is communicated with a reduced titanium liquid tank 15, the reduced titanium liquid tank 15 is communicated with the hot material inlet at the bottom of a reduced titanium liquid cooler 17 through a circulating pump 16 pipeline, the upper cold charge inlet of the reduced titanium liquid cooler 17 is communicated with a circulating water feeding pipe, and the lower cold charge outlet is communicated with a circulating water return pipe;
the cold material outlet at the top of the reduced titanium liquid cooler 17 is divided into two paths, one path of pipeline is communicated with the top of the electrolytic bath 14, the other path of pipeline is communicated with the ferrous crystallizer at the crystallization-hydrolysis working section through a control valve 19, an on-line analyzer 18 is arranged on the hot material outlet pipeline at the top of the reduced titanium liquid cooler 17, and the control valve 19 is controlled by the on-line analyzer 18 in a linkage manner.
Further, stirrers are arranged in the slurry tank 4 and the reduced titanium liquid tank 15, and driving motors of the stirrers are of variable-frequency speed regulation type.
Further, the acidolysis titanium liquid cooler 1 and the reduction titanium liquid cooler 17 are both vertical graphite heat exchangers.
Further, the outside of the settling tank 2, the slurry pump 3, the slurry tank 4, the plate-frame feed pump 5, the dilute titanium liquid storage tank 9, the pipe passing feed pump 10, the tubular filter 11 and the clean titanium liquid storage tank 12 are all provided with an outer heat insulation layer.
Further, a hopper 7 is correspondingly arranged below the plate-and-frame filter press 6, and a belt transmission device 8 is correspondingly arranged below a bottom discharge hole of the hopper 7.
The invention has the following beneficial technical effects:
the titanium liquid purification and reduction method controls the indexes of the reduced titanium liquid sent to a ferrous crystallizer of a downstream crystallization-hydrolysis section as follows (normal pressure hydrolysis pigment level):
total titanium content: 120-135 g/L of the total amount of the active ingredients,
f value: 1.7 to 1.9 of a polymer,
trivalent titanium: 1.5-3 g/L
Stability: not less than 300
The following advantages exist simultaneously:
(1) the titanium liquid is reduced without using iron powder, thereby reducing the labor intensity, improving the labor environment, and eliminating the related storehouses, hoisting facilities and metering and feeding devices, thereby reducing the labor cost and the investment cost.
(2) The same amount of titanium liquid is reduced, the electricity cost is much lower than that of iron powder, the electrolytic reduction time is shorter than that of iron powder reduction, and the iron powder also reacts with sulfuric acid in an acidolysis tank or a reduction tank to generate FeSO4And hydrogen, iron powder and sulfuric acid are wasted, and the FeSO is required to be subjected to subsequent crystallization and waste acid concentration4Separated out, consumes more cold and heat and leads the iron powder and the sulfur with higher valueConversion of acid to very low value FeSO4·7H2O and FeSO4·H2O, does not accord with economic rules; in addition, the iron powder is usually directly added into an acidolysis tank or a reduction tank, and because of large acidity and high temperature, the iron powder reacts violently in the tank, so that the phenomenon of runaway of a 'top pot' often occurs; compared with an iron powder reduction method, the electrolysis reduction method is efficient and convenient, and basically has no waste except a small amount of heat generated in the electrolysis process, so that energy conservation, consumption reduction and cost saving are really realized; meanwhile, a solid foundation is laid for further realizing the clean production of the titanium white.
(3) Compared with the prior production operation, the method has the advantages that the heat of the high-temperature titanium acidolysis solution in the acidolysis tank or the secondary dissolving tank is fully utilized, the acidolysis tank is stirred and cooled by using compressed air after acidolysis curing is finished, and the reaction occurs in the process, namely 4FeSO4+O2+2H2SO4= Fe2(SO4)3+2H2O
Therefore, the cold energy of the titanium acidolysis solution is not utilized, and part of reduced Fe is utilized2+And then changed into Fe3+More iron powder consumption is indirectly brought, and more sulfuric acid consumption is directly brought, so that the production cost is further increased; if continuous acidolysis is adopted, circulating water is also adopted for cooling before the acidolysis titanium solution is sent to the reduction tank, so that the consumption of the reduced iron powder and the sulfuric acid is reduced compared with intermittent acidolysis, but compared with the method, the method not only wastes the reaction heat, but also consumes the circulating water.
(4) The prior production technology adopts reduction and then sedimentation filtration in order to prevent part of Fe in the subsequent flow operation2+Is oxidized into Fe by air3+Therefore, more iron powder is generally added to increase Ti4+Reduction to Ti3+Therefore, Ti content in the subsequent hydrolysis step becomes large3+Does not participate in hydrolysis to generate metatitanic acid, not only wastes more iron powder, but also loses more Ti resources. The operation is completely empirical. The invention adopts a method of firstly settling, filtering and then reducing, so that the reduction can be automated and precise.
Drawings
FIG. 1 is a system diagram of the purification and reduction method of titanium dioxide acidolysis titanium liquid by sulfuric acid process.
Wherein: 1 acidolysis titanium liquid cooler, 2 settling tanks, 3 slurry pumps, 4 slurry tanks, 5 plate-frame feed pumps, 6 plate-frame filter presses, 7 hoppers, 8 belt transmission devices, 9 dilute titanium liquid storage tanks, 10 pipe passing feed pumps, 11 pipe filters, 12 clear titanium liquid storage tanks, 13 electrolytic tank feed pumps, 14 electrolytic tanks, 15 reduced titanium liquid tanks, 16 circulating pumps, 15 reduced titanium liquid tanks, 17 reduced titanium liquid coolers, 18 on-line analyzers and 19 control valves.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Example 1
See figure 1, a system for a titanium dioxide acidolysis titanium liquid purification and reduction method by a sulfuric acid method,
comprises an acidolysis titanium liquid cooler 1, a settling tank 2, a slurry tank 4, a plate-and-frame filter press 6, a dilute titanium liquid storage tank 9, an electrolytic tank 14, a reduced titanium liquid tank 15 and a reduced titanium liquid cooler 17;
the hot material inlet at the bottom of the titanium acidolysis liquid cooler 1 is communicated with the acidolysis tank or the secondary dissolving tank through a pipeline, the cold material inlet at the upper part of the preheater 1 is communicated with the dilute titanium liquid storage tank after the disc filtration of the crystallization-hydrolysis section through a pipeline, the cold material outlet at the lower part of the preheater 1 is communicated with the tubular filter feeding tank of the crystallization-hydrolysis section through a pipeline, the hot material outlet at the top of the preheater 1 is communicated with the inlet of the central cylinder of the settling tank 2 through an outlet pipe, and the outlet pipe is communicated with a flocculating agent feeding pipe;
the bottom outlet of the settling tank 2 is communicated with the top inlet of a slurry tank 4 through a slurry pump 3 pipeline, the lower outlet of the slurry tank 4 is communicated with the feed inlet of a plate-and-frame filter press 6 through a plate-and-frame feed pump 5 pipeline, the filtrate outlet of the plate-and-frame filter press 6 is communicated with the central cylinder inlet of the settling tank 2 through a pipeline, the upper overflow port of the settling tank 2 is communicated with the top inlet of a dilute titanium liquid storage tank 9 through a pipeline, the bottom outlet of the dilute titanium liquid storage tank 9 is communicated with the lower feed inlet of a tubular filter 11 through a feed pump 10, the upper discharge port pipeline of the tubular filter 11 is communicated with the top feed inlet of a clean titanium liquid storage tank 12, the bottom slurry outlet pipeline of the tubular filter 11 is communicated with the top inlet of the slurry tank 4, the lower outlet of the clean titanium liquid storage tank 12 is communicated with the top inlet of an electrolytic tank 14 through an electrolytic tank feed pump 13 pipeline, the bottom outlet pipeline of the electrolytic tank 14 is communicated with a reduced titanium liquid tank 15, the reduced titanium liquid tank 15 is communicated with the hot material inlet at the bottom of a cooler 17 through a circulating pump 16 pipeline, the upper cold charge inlet of the reduced titanium liquid cooler 17 is communicated with a circulating water feeding pipe, and the lower cold charge outlet is communicated with a circulating water return pipe;
the cold material outlet at the top of the reduced titanium liquid cooler 17 is divided into two paths, one path of pipeline is communicated with the top of the electrolytic bath 14, the other path of pipeline is communicated with the ferrous crystallizer at the crystallization-hydrolysis working section through a control valve 19, an online analyzer 18 is arranged on the outlet pipeline at the top of the reduced titanium liquid cooler 17, and the control valve 19 is controlled by the online analyzer 18 in a linkage manner.
Hopper 7 is correspondingly arranged below plate and frame filter press 6, and belt transmission device 8 is correspondingly arranged below the bottom discharge hole of hopper 7.
Both the preheater 1 and the cooler 17 are vertical graphite heat exchangers.
The settling tank 2 is made of steel equipment, the bottom of the settling tank is paved by acid-resistant bricks, the side surface of the settling tank is lined with butyl rubber, the rake paddles are coated with the butyl rubber and driven by a variable frequency motor.
The mud tank 4 and the reduction titanium liquid tank 15 are both vertical equipment with a steel shell lined with butyl rubber, butyl rubber stirrers coated with butyl rubber are arranged in the mud tank 4 and the reduction titanium liquid tank 15, and driving motors of the stirrers are of a variable-frequency speed regulation type.
The dilute titanium liquid storage tank 11 and the clear titanium liquid storage tank 14 are both vertical devices of steel shell lining butyl rubber. The hopper 9 is open equipment and is lined with butyl rubber.
The mud pump 3, the plate frame feeding pump 5, the pipe passing feeding pump 10, the electrolytic bath feeding pump 13 and the circulating pump 18 are all horizontal engineering plastic pumps.
The electrolytic cell 14 is a cuboid horizontal closed device, a steel shell is lined with butyl rubber, the electrolytic cell 14 is wrapped with an insulating material, the anode and the cathode are made of flake graphite materials and are respectively connected with the anode and the cathode of a direct current power supply, and the direct current power supply has voltage and current regulation capacity.
And outer heat-insulating layers are arranged on the outer sides of the settling tank 2, the slurry pump 3, the slurry tank 4, the plate-frame feed pump 5, the dilute titanium liquid storage tank 9, the pipe passing feed pump 10, the tubular filter 11 and the clear titanium liquid storage tank 12.
An anti-scalding protective layer is arranged outside the electrolytic tank 14, the reduced titanium liquid tank 15 and the circulating pump 16.
Example 2
The reduction process of example 1, comprising the steps of:
step (1): a cooling process, wherein the cooling process comprises the following steps,
introducing the titanium acidolysis solution cured in the acidolysis tank or the secondary dissolving tank into an inlet at the bottom of a titanium acidolysis solution cooler 1, introducing the dilute titanium solution filtered by a disc in a crystallization-hydrolysis section into an inlet at the side surface of the upper part of the titanium acidolysis solution cooler 1, after indirect heat exchange, raising the temperature of the dilute titanium solution from about 20 ℃ to about 55 ℃, then returning the dilute titanium solution to a feeding tank of a tubular filter in the crystallization-hydrolysis section from an outlet at the side surface of the lower part of the titanium acidolysis solution cooler 1, cooling the titanium acidolysis solution to about 60 ℃, then mixing the dilute titanium solution from the top of the titanium acidolysis solution cooler 1 with a flocculating agent in proportion, and then feeding the mixed volume ratio of the cooled titanium acidolysis solution and the flocculating agent into a continuous settling tank (2), wherein the mixed volume ratio of the cooled titanium acidolysis solution and the flocculating agent is 1: 0.03-1: 0.07.
Step (2): a settling working procedure is carried out,
continuously settling the mixed solution in a settling tank 2 for 2-4 hours to obtain supernatant and lower layer slurry, introducing the supernatant into a tubular filter 11 for fine filtration to obtain clear titanium solution, wherein the solid content of impurities in the clear titanium solution is lower than 10ppm, and the temperature is 50-55 ℃;
and (3): a reduction process of the acidolysis titanium solution,
introducing the clean titanium solution into the electrolytic cell 14, and switching on a direct current power supply of the electrolytic cell 14 to perform electrochemical reaction as follows:
anode: 4OH- -4e = 2H2O+O2↑
Cathode: fe3+ +e = Fe2+
Ti4+ +e = Ti3+
The general reaction formula is as follows: 2Fe2(SO4)3+2H2O= 4FeSO4+2H2SO4+O2↑
2TiOSO4 +H2SO4= Ti2(SO4)3+H2O
The electrolytic reaction temperature in the electrolytic cell 14 is 60-75 ℃ to obtain the Fe-containing alloy2+And Ti3+Reducing the titanium solution;
and (4): a cooling process, wherein the cooling process comprises the following steps,
introducing reduced titanium liquid into the bottom of the reduced titanium liquid cooler 17, cooling the reduced titanium liquid to 40-45 ℃ by circulating water, refluxing the cooled reduced titanium liquid into the electrolytic bath 14, and analyzing Ti in the cooled reduced titanium liquid by the online analyzer 183+In an amount of Ti3+When the content is 1.5-3 g/L, opening the control valve 19 in an interlocking manner to discharge part of the cooled reduced titanium liquid, and conveying the part to a ferrous crystallizer of a downstream crystallization-hydrolysis section through a pipeline, wherein the total titanium content of the reduced titanium liquid is as follows: 120-135 g/L, F value: 1.7-1.9, trivalent titanium: 1.5-3 g/L, stability: not less than 300.
In the step (4), the pressure of the reduction titanium liquid introduced into the bottom of the reduction titanium liquid cooler 17 is about 0.46PaG, and the water pressure introduced into the circulating water feeding pipe of the cooler 17 is about 0.45PaG, so that the operation pressure of the reduction titanium liquid in the cooler 17 is slightly higher than the operation pressure of the circulating water, the reduction titanium liquid is prevented from leaking in the cooler 17, and the qualified reduction titanium liquid is prevented from being polluted.
Therefore, the invention relates to a method and a system for purifying and reducing titanium dioxide acidolysis titanium liquid by a sulfuric acid method,
(1) the titanium liquid is reduced without using iron powder, thereby reducing the labor intensity, improving the labor environment, and eliminating the related storehouses, hoisting facilities and metering and feeding devices, thereby reducing the labor cost and the investment cost.
(2) The same amount of titanium liquid is reduced, the electricity cost is much lower than that of iron powder, the electrolytic reduction time is shorter than that of iron powder reduction, and the iron powder also reacts with sulfuric acid in an acidolysis tank or a reduction tank to generate FeSO4And hydrogen, iron powder and sulfuric acid are wasted, and the subsequent crystallization process and waste acid concentration process are requiredThe FeSO4Separated out, consumes more cold and heat, and changes the iron powder and the sulfuric acid with higher value into FeSO with lower value4·7H2O and FeSO4·H2O, does not conform to economic laws. In addition, the iron powder is usually directly added into an acidolysis tank or a reduction tank, because of large acidity and high temperature, the iron powder reacts violently in the tank and is often out of control due to 'hot pot', compared with an iron powder reduction method, the electrolytic reduction method disclosed by the invention is efficient and convenient, generates little heat in the electrolytic process, basically has no waste, and really achieves the purposes of saving energy, reducing consumption and saving cost. Meanwhile, a solid foundation is laid for further realizing the clean production of the titanium white.
(3) Utilize acidolysis titanium liquid cooler 1 to utilize the heat of high temperature acidolysis titanium liquid in acidolysis jar or the second grade dissolving tank completely, compare current production operation, utilize compressed air stirring cooling after acidolysis jar acidolysis curing, take place the reaction in this process: 4FeSO4+ O2+2H2SO4= Fe2(SO4)3+2H2O
Therefore, the cold energy of the titanium acidolysis solution is not utilized, and part of reduced Fe2+ is changed into Fe3+, which indirectly brings more iron powder consumption and directly brings more sulfuric acid consumption, thereby further increasing the production cost. If continuous acidolysis is adopted, circulating water is also adopted for cooling before the acidolysis titanium solution is sent to the reduction tank, so that the consumption of the reduced iron powder and the sulfuric acid is reduced compared with intermittent acidolysis, but compared with the method, the method not only wastes the reaction heat, but also consumes the circulating water.
(4) The existing production technology adopts reduction and then sedimentation filtration, so as to prevent part of Fe2+ from being oxidized into Fe3+ by air in the subsequent flow operation, more iron powder is usually added, more Ti4+ is reduced into Ti3+, and more Ti3+ does not participate in hydrolysis to generate metatitanic acid in the subsequent hydrolysis process, so that not only more iron powder is wasted, but also more Ti resources are lost in white. The operation is completely empirical. The invention adopts a method of firstly settling, filtering and then reducing, so that the reduction can be automated and precise.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (7)
1. A method for purifying and reducing titanium dioxide acidolysis titanium liquid by a sulfuric acid method is characterized by comprising the following steps: the method comprises the following steps:
step (1): a cooling process, wherein the cooling process comprises the following steps,
introducing the titanium acidolysis solution cured in the acidolysis tank or the secondary dissolving tank into an inlet at the bottom of a titanium acidolysis solution cooler (1), introducing the dilute titanium solution filtered by a disc in a crystallization-hydrolysis working section into an inlet at the upper side of the titanium acidolysis solution cooler (1), after indirect heat exchange, raising the temperature of the dilute titanium solution from about 20 ℃ to about 55 ℃, then returning the dilute titanium solution to a feeding tank of a tubular filter in the crystallization-hydrolysis working section from an outlet at the lower side of the titanium acidolysis solution cooler (1), cooling the titanium acidolysis solution to about 60 ℃, then mixing the dilute titanium solution from the top of the titanium acidolysis solution cooler (1) with a flocculating agent in proportion and then entering a continuous settling tank (2), wherein the mixing volume ratio of the cooled titanium acidolysis solution and the flocculating agent is 1: 0.03-1: 0.07;
step (2): a settling working procedure is carried out,
continuously settling the mixed solution in a settling tank (2) for 2-4 hours to obtain supernatant and lower layer slurry, introducing the supernatant into a tubular filter (11) for fine filtration to obtain clear titanium solution, wherein the impurity solid content of the clear titanium solution is lower than 10ppm, and the temperature is 50-55 ℃;
and (3): a reduction process of the acidolysis titanium solution,
introducing the clean titanium solution into an electrolytic tank (14), and switching on a direct current power supply of the electrolytic tank (14) to perform electrochemical reaction as follows:
anode: 4OH- -4e = 2H2O+O2↑
Cathode: fe3+ +e = Fe2+
Ti4+ +e = Ti3+
The general reaction formula is as follows: 2Fe2(SO4)3+2H2O= 4FeSO4+2H2SO4+O2↑
2TiOSO4 +H2SO4= Ti2(SO4)3+H2O
The electrolytic reaction temperature in the electrolytic cell (14) is 60-75 ℃ to obtain the Fe-containing material2+And Ti3+Reducing the titanium solution;
and (4): a cooling process, wherein the cooling process comprises the following steps,
introducing reduced titanium liquid into the bottom of the reduced titanium liquid cooler (17), cooling the reduced titanium liquid to 40-45 ℃ by circulating water, refluxing the cooled reduced titanium liquid into the electrolytic bath (14), and analyzing Ti in the cooled reduced titanium liquid by an online analyzer (18) at the same time3+In an amount of Ti3+When the content is 1.5-3 g/L, opening a control valve (19) in an interlocking manner to discharge part of the cooled reduced titanium liquid, and conveying the part of the cooled reduced titanium liquid to a ferrous crystallizer of a downstream crystallization-hydrolysis section through a pipeline, wherein the total titanium content of the reduced titanium liquid is as follows: 120-135 g/L, F value: 1.7-1.9, trivalent titanium: 1.5-3 g/L, stability: not less than 300.
2. The method for purifying and reducing the titanium dioxide acidolysis solution of sulfuric acid method titanium dioxide according to claim 1, which is characterized in that: the operation pressure of the titanium liquid reduction in the step (4) is higher than the operation pressure of circulating water.
3. The system for the purification and reduction method of the titanium dioxide acidolysis titanium liquid by the sulfuric acid method according to the claims 1-2, which is characterized in that:
comprises an acidolysis titanium liquid cooler (1), a settling tank (2), a slurry tank (4), a plate-and-frame filter press (6), a dilute titanium liquid storage tank (9), an electrolytic tank (14), a reduced titanium liquid tank (15) and a reduced titanium liquid cooler (17); the top of the electrolytic cell (14) is communicated with an oxygen emptying pipe;
the hot material inlet at the bottom of the titanium acidolysis liquid cooler (1) is communicated with the acidolysis tank or the secondary dissolving tank through a pipeline, the cold material inlet at the upper part of the titanium acidolysis liquid cooler (1) is communicated with the dilute titanium liquid storage tank after being filtered by a crystallization-hydrolysis section disc through a pipeline, the cold material outlet at the lower part of the titanium acidolysis liquid cooler (1) is communicated with the feeding tank of a crystallization-hydrolysis section tubular filter through a pipeline, the hot material outlet at the top of the titanium acidolysis liquid cooler (1) is communicated with the central cylinder inlet of the settling tank (2) through an outlet pipe, and the outlet pipe is communicated with a flocculant feeding pipe;
the bottom outlet of the settling tank (2) is communicated with the top inlet of a slurry tank (4) through a slurry pump (3) pipeline, the lower outlet of the slurry tank (4) is communicated with the feed inlet of a plate-and-frame filter press (6) through a plate-and-frame feed pump (5) pipeline, the filtrate outlet of the plate-and-frame filter press (6) is communicated with the central cylinder inlet of the settling tank (2) through a pipeline, the upper overflow port of the settling tank (2) is communicated with the top inlet of a dilute titanium liquid storage tank (9) through a pipeline, the bottom outlet of the dilute titanium liquid storage tank (9) is communicated with the lower feed inlet of a tubular filter (11) through a feed pump (10), the upper discharge port of the tubular filter (11) is communicated with the top feed inlet of a clean titanium liquid storage tank (12) through a pipeline, the bottom slurry outlet pipeline of the tubular filter (11) is communicated with the top inlet of the slurry tank (4), the lower outlet of the clean titanium liquid storage tank (12) is communicated with the top inlet of an electrolytic tank (14) through an electrolytic tank feed pump (13) pipeline, an outlet at the bottom of the electrolytic tank (14) is communicated with a reduced titanium liquid tank (15) through a pipeline, the reduced titanium liquid tank (15) is communicated with a hot material inlet at the bottom of a cooler (17) through a circulating pump (16) through a pipeline, an upper cold material inlet of the cooler (17) is communicated with a circulating water feeding pipe, and a lower cold material outlet is communicated with a circulating water return pipe;
the hot material outlet at the top of the cooler (17) is divided into two paths, one path of pipeline is communicated with the top of the electrolytic tank (14), the other path of pipeline is communicated with the ferrous crystallizer of the crystallization-hydrolysis working section through a control valve (19), an online analyzer (18) is arranged on the hot material outlet pipeline at the top of the cooler (17), and the control valve (19) is controlled by the online analyzer (18) in a linkage mode.
4. The system for purifying and reducing the titanium dioxide acidolysis solution according to claim 3, which is characterized in that: stirrers are arranged in the slurry tank (4) and the reduced titanium liquid tank (15), and driving motors of the stirrers are of variable-frequency speed regulation type.
5. The system for purifying and reducing the titanium dioxide acidolysis solution according to claim 3, which is characterized in that: the acidolysis titanium liquid cooler (1) and the reduction titanium liquid cooler (17) are both vertical graphite heat exchangers.
6. The system for purifying and reducing the titanium dioxide acidolysis solution according to claim 3, which is characterized in that: and the outer sides of the settling tank (2), the slurry pump (3), the slurry tank (4), the plate frame feed pump (5), the dilute titanium liquid storage tank (9), the pipe passing feed pump (10), the tubular filter (11) and the clear titanium liquid storage tank (12) are all provided with outer heat-insulating layers.
7. The system for purifying and reducing the titanium dioxide acidolysis solution according to claim 3, which is characterized in that: the lower part of the plate-and-frame filter press (6) is correspondingly provided with a hopper (7), and the lower part of a bottom discharge hole of the hopper (7) is correspondingly provided with a belt transmission device (8).
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4206021A (en) * | 1978-03-02 | 1980-06-03 | Thann Et Mulhouse S.A. | Process for the production of pigmentary titanium dioxide by the sulphuric acid method |
| CN104628208A (en) * | 2015-02-12 | 2015-05-20 | 四川理工学院 | Zero-emission resource recycling method of high-salt sodium sulfate wastewater |
| CN212247158U (en) * | 2020-04-08 | 2020-12-29 | 南京怡丰月明环保科技有限公司 | Ionic membrane electric reduction device |
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2021
- 2021-07-16 CN CN202110804997.6A patent/CN113461048A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4206021A (en) * | 1978-03-02 | 1980-06-03 | Thann Et Mulhouse S.A. | Process for the production of pigmentary titanium dioxide by the sulphuric acid method |
| CN104628208A (en) * | 2015-02-12 | 2015-05-20 | 四川理工学院 | Zero-emission resource recycling method of high-salt sodium sulfate wastewater |
| CN212247158U (en) * | 2020-04-08 | 2020-12-29 | 南京怡丰月明环保科技有限公司 | Ionic membrane electric reduction device |
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