CN103663550A - Preparation method of titanium dioxide - Google Patents
Preparation method of titanium dioxide Download PDFInfo
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- CN103663550A CN103663550A CN201310661009.2A CN201310661009A CN103663550A CN 103663550 A CN103663550 A CN 103663550A CN 201310661009 A CN201310661009 A CN 201310661009A CN 103663550 A CN103663550 A CN 103663550A
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- preheating
- titanium tetrachloride
- oxidation reaction
- oxygen
- titanium dioxide
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- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims abstract description 128
- 239000004408 titanium dioxide Substances 0.000 title claims abstract description 61
- 238000002360 preparation method Methods 0.000 title abstract 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 73
- 239000004576 sand Substances 0.000 claims abstract description 65
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 55
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 claims abstract description 50
- 238000000034 method Methods 0.000 claims abstract description 37
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 claims abstract description 30
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 claims abstract description 27
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims abstract description 21
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 20
- 239000000203 mixture Substances 0.000 claims abstract description 19
- 238000010438 heat treatment Methods 0.000 claims abstract description 17
- 239000007787 solid Substances 0.000 claims abstract description 17
- 238000000926 separation method Methods 0.000 claims abstract description 15
- 238000002156 mixing Methods 0.000 claims abstract description 12
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 claims abstract description 11
- 238000006243 chemical reaction Methods 0.000 claims abstract description 11
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 4
- 239000000463 material Substances 0.000 claims description 58
- 231100000241 scar Toxicity 0.000 claims description 32
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 29
- 239000001301 oxygen Substances 0.000 claims description 29
- 229910052760 oxygen Inorganic materials 0.000 claims description 29
- 239000007789 gas Substances 0.000 claims description 24
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 22
- 229910052801 chlorine Inorganic materials 0.000 claims description 22
- 239000000460 chlorine Substances 0.000 claims description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 239000011541 reaction mixture Substances 0.000 claims description 19
- 238000005406 washing Methods 0.000 claims description 14
- 238000004537 pulping Methods 0.000 claims description 10
- 239000002002 slurry Substances 0.000 claims description 8
- 238000001035 drying Methods 0.000 claims description 6
- 239000008247 solid mixture Substances 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 3
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 abstract description 10
- 229910001882 dioxygen Inorganic materials 0.000 abstract description 10
- 235000012239 silicon dioxide Nutrition 0.000 abstract description 2
- 238000007664 blowing Methods 0.000 description 22
- 230000003647 oxidation Effects 0.000 description 17
- 230000008569 process Effects 0.000 description 15
- 238000004519 manufacturing process Methods 0.000 description 11
- 239000002245 particle Substances 0.000 description 11
- 206010039509 Scab Diseases 0.000 description 10
- 238000005243 fluidization Methods 0.000 description 9
- 238000009924 canning Methods 0.000 description 6
- 238000005660 chlorination reaction Methods 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- 239000000428 dust Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 4
- 238000007599 discharging Methods 0.000 description 4
- 238000004064 recycling Methods 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 3
- VXEGSRKPIUDPQT-UHFFFAOYSA-N 4-[4-(4-methoxyphenyl)piperazin-1-yl]aniline Chemical compound C1=CC(OC)=CC=C1N1CCN(C=2C=CC(N)=CC=2)CC1 VXEGSRKPIUDPQT-UHFFFAOYSA-N 0.000 description 2
- 208000032544 Cicatrix Diseases 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000037387 scars Effects 0.000 description 2
- 239000005049 silicon tetrachloride Substances 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 239000002912 waste gas Substances 0.000 description 2
- 235000017166 Bambusa arundinacea Nutrition 0.000 description 1
- 235000017491 Bambusa tulda Nutrition 0.000 description 1
- 241001330002 Bambuseae Species 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 235000015334 Phyllostachys viridis Nutrition 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 241001426407 Umbrina coroides Species 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 239000011425 bamboo Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
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- 239000000446 fuel Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000006210 lotion Substances 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002006 petroleum coke Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 239000004071 soot Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
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- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
The invention relates to a preparation method of titanium dioxide. The method comprises the following steps: (1) burning dimethyl ether to provide thermal energy to carry out a first pre-heating treatment on titanium tetrachloride; (2) mixing aluminum powder, chlorine gas and titanium tetrachloride, which has been subjected to the first pre-heating treatment, in an aluminum trichloride generator so as to obtain a mixture of aluminum trichloride and titanium tetrachloride, wherein the heat generated by the reaction between the aluminum powder and the chlorine gas carries out a second pre-heating treatment on the titanium tetrachloride, and the mole ratio of aluminum powder to the chlorine gas is 1:1 to 1:5; (3) burning dimethyl ether to provide thermal energy to carry out a first pre-heating treatment on oxygen gas; (4) burning toluene to provide thermal energy to carry out a second pre-heating treatment on the oxygen gas which has been subjected to the first pre-heating treatment; (5) mixing the mixture of aluminum trichloride and titanium tetrachloride with the oxygen gas, which has been subjected to the second pre-heating treatment, adding silicon dioxide as the scar-removing sand; and (6) carrying out a gas-solid separation treatment on the mixed products of oxidation reaction so as to obtain titanium dioxide and chlorine gas.
Description
Technical Field
The invention relates to the field of chemical industry, in particular to a method for preparing titanium dioxide.
Background
The current methods for producing titanium dioxide are mainly sulfuric acid method and chlorination method. The sulfuric acid process is gradually replaced by the chlorination process due to long process, serious pollution and poor product quality.
CN1066043 discloses a process for preparing rutile titanium dioxide, which comprises 1), uniformly mixing high titanium slag and petroleum coke, putting into a chlorination furnace, introducing chlorine gas at 800-900 ℃ for boiling chlorination, 2), separating and purifying crude titanium tetrachloride obtained after chlorination to remove impurities such as magnesium, iron, silicon and vanadium, and obtain refined titanium tetrachloride, 3), converting the prepared refined titanium tetrachloride liquid into gas phase in an evaporator, preheating to 450-800 ℃, 4), mixing the gas phase titanium tetrachloride with a small amount of crystal type converting agent, namely, gas phase aluminum trichloride, entering into an oxidation furnace, heating oxygen by a plasma generator, entering into the oxidation furnace, carrying out oxidation reaction at 1300-1500 ℃ for less than 0.1 second to generate solid phase titanium dioxide, 5), rapidly removing titanium dioxide solid powder from a reaction zone and rapidly removing reaction heat, collecting titanium dioxide to generate chlorine gas, returning to the chlorination furnace, 6) pulping the collected titanium dioxide particle powder into liquid, carrying out two-stage separation, carrying out post-treatment on fine particle titanium dioxide smaller than 1 micron, grinding coarse particles, then carrying out secondary separation, 7), carrying out coating post-treatment by using an auxiliary agent at the temperature of 50-70 ℃ and the pH = 7-8, 8), carrying out twice filtration on the post-treated titanium dioxide slurry, wherein the water content of the fed material is smaller than 45%, the water content of the discharged material is smaller than 1%, 9) drying at the temperature of 120-160 ℃, and carrying out superfine grinding, wherein the average particle size of the product is 70% below 0.3 mu m.
However, the current means of preparing titanium dioxide is still in need of improvement.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. To this end, it is an object of the present invention to propose a process which enables efficient production of titanium dioxide.
In one aspect of the invention, a method of making titanium dioxide is provided. According to an embodiment of the invention, the method comprises: (1) providing heat by burning dimethyl ether to carry out first preheating on titanium tetrachloride; (2) mixing aluminum powder, chlorine and the titanium tetrachloride which is preheated for the first time, and reacting the aluminum powder and the chlorine to generate aluminum trichloride so as to obtain a mixture containing the aluminum trichloride and the titanium tetrachloride, wherein the titanium tetrachloride is preheated for the second time by heat generated by the reaction of the aluminum powder and the chlorine, and the molar ratio of the aluminum powder to the chlorine is 1: 1-1: 5; (3) providing heat by burning dimethyl ether to carry out first preheating on oxygen; (4) providing heat by burning toluene to perform a second preheating on the oxygen subjected to the first preheating; (5) mixing the mixture containing aluminum trichloride and titanium tetrachloride obtained in the step (2) with the oxygen subjected to the second preheating obtained in the step (4) in an oxidation reaction device, and allowing titanium tetrachloride and oxygen to undergo an oxidation reaction, wherein silica is added to the oxidation reaction device as scar removing sand, so as to obtain an oxidation reaction mixture containing titanium dioxide and chlorine; and (6) carrying out gas-solid separation treatment on the oxidation reaction mixture so as to respectively obtain titanium dioxide and chlorine, wherein the gas-solid separation treatment on the oxidation reaction mixture further comprises the following steps: rapidly cooling the oxidation reaction mixture by using circulating water; carrying out gas-solid separation treatment on the oxidation reaction mixture by using a bag filter so as to respectively obtain gas tail gas containing chlorine and a solid mixture containing titanium dioxide and scar removing sand; adding the solid mixture to a base stock pulping tank, and pulping by adding demineralized water to the base stock pulping tank; adding the obtained slurry into a scar removing sand separating device so as to separate and obtain a scar removing sand reclaimed material and a titanium dioxide slurry; washing and steam drying the recovered scar-removing sand to obtain dried scar-removing sand; and returning the dried scar-removing sand to the oxidation reaction device. According to the method for preparing titanium dioxide, the raw materials for titanium tetrachloride oxidation reaction can be effectively and rapidly preheated, and aluminum trichloride is obtained, so that titanium dioxide with uniform particle size can be effectively generated, the efficiency for preparing titanium dioxide can be improved, and meanwhile, the recycling of scar removing sand is realized through the method, so that the cost for preparing titanium dioxide is remarkably reduced.
In addition, the method for preparing titanium dioxide according to the above embodiment of the present invention may also have the following additional technical features:
in one embodiment of the invention, the temperature of the first preheated titanium tetrachloride is not less than 270 degrees celsius; the temperature of the titanium tetrachloride subjected to the second preheating is not lower than 350 ℃; the temperature of the oxygen subjected to the first preheating is not lower than 750 ℃; the temperature of the oxygen subjected to the second preheating is not lower than 1500 ℃. Thereby, the efficiency of producing titanium dioxide can be further improved.
In one embodiment of the present invention, the first preheating of titanium tetrachloride and the first preheating of oxygen are both indirect heating in step (1) and step (3), and toluene is mixed with the first preheated oxygen and combusted in step (4) to perform the second preheating of the first preheated oxygen by direct heating. Thereby, the preheating efficiency can be further improved, thereby improving the efficiency of producing titanium dioxide.
In one embodiment of the present invention, in the step (2), the aluminum powder and the chlorine gas are mixed in a ratio of 1: 1-1: 5 mol ratio, so that the proportion of the aluminum trichloride is 0.01-1% in the mixture containing the aluminum trichloride and the titanium tetrachloride. Therefore, the aluminum powder and the chlorine can react under the most appropriate proportioning condition, and the proportion of the aluminum trichloride in the mixture of the aluminum trichloride and the titanium tetrachloride is maintained within the range of 0.01-1%, so that the generation of titanium dioxide crystals is facilitated, and the production efficiency of the titanium dioxide is improved.
In one embodiment of the present invention, in step (6), the oxidation reaction mixture is rapidly cooled to below 500 degrees celsius within 1 minute using circulating water. Therefore, the oxidation reaction mixture can be efficiently and quickly cooled, so that titanium dioxide crystals are prevented from rapidly growing and being bonded with each other at high temperature to form scars, and chlorine gas separated from gas and solid can be recycled, so that the production cost of titanium dioxide is remarkably reduced.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic flow diagram of a process for producing titanium dioxide according to one embodiment of the present invention;
FIG. 2 is a schematic flow diagram of gas-solid separation in a process for producing titanium dioxide according to yet another embodiment of the present invention;
fig. 3 is a schematic view of the structure of a continuous feeding apparatus for scab removing sand used in a method for preparing titanium dioxide according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In one aspect of the present invention, the present invention provides a method of preparing titanium dioxide, referring to fig. 1 to 3, according to an embodiment of the present invention, the method comprising:
s100: first preheating of titanium tetrachloride
The dimethyl ether is combusted to provide heat, and the titanium tetrachloride is subjected to first preheating, so that the titanium tetrachloride subjected to the first preheating treatment can be obtained. The manner of performing the first preheating treatment of titanium tetrachloride using dimethyl ether according to an embodiment of the present invention is not particularly limited, and according to a specific embodiment of the present invention, the first preheating treatment of titanium tetrachloride using heat generated by combustion of dimethyl ether may be performed using an indirect heating manner. According to the embodiment of the invention, the temperature of the silicon tetrachloride subjected to the first preheating treatment is not particularly limited, according to the specific embodiment of the invention, the temperature of the silicon tetrachloride subjected to the first preheating treatment is not lower than 270 ℃, in the step, the used dimethyl ether is used as a clean energy source, the dimethyl ether is inflammable, the combustion performance is good, the heat efficiency is high, no residue and no black smoke are generated in the combustion process, carbon deposition on a heating coil is little, and the heat transfer is hardly influenced, so that the capital and labor investment of a soot blowing system and the overhaul workload are reduced. Therefore, the titanium tetrachloride can be heated by effectively utilizing the heat generated by burning the dimethyl ether, the preheating efficiency and the titanium dioxide production efficiency are further improved, and meanwhile, the dimethyl ether is used as a fuel, so that the environment is obviously improved, the property is stable, and the transportation and the storage are safer.
S200: secondary preheating of titanium tetrachloride
Mixing aluminum powder, chlorine and titanium tetrachloride subjected to first preheating treatment in an aluminum trichloride generator, and reacting the aluminum powder and the chlorine to generate aluminum trichloride, so that a mixture containing the aluminum trichloride and the titanium tetrachloride can be obtained, wherein the reaction of the aluminum powder and the chlorine to generate the aluminum trichloride is an exothermic reaction, so that the titanium tetrachloride can be subjected to second preheating treatment by virtue of the released heat, and meanwhile, the mixing molar ratio of the aluminum powder to the chlorine is 1: 1-1: 5. according to an embodiment of the present invention, the temperature of the titanium tetrachloride subjected to the second preheating treatment is not particularly limited, and according to a specific embodiment of the present invention, the temperature of the titanium tetrachloride subjected to the second preheating treatment is not lower than 350. Therefore, the oxidation reaction efficiency can be further improved, and the production cost of the titanium dioxide is reduced.
According to the embodiment of the invention, the mixing molar ratio of the aluminum powder to the chlorine gas is 1: 1-1: 5, the aluminum powder and the chlorine gas react in a proper proportion, and the proportion of the aluminum trichloride in the mixture of the aluminum trichloride and the titanium tetrachloride is maintained within the range of 0.01-1%, so that the conversion rate of titanium dioxide crystals is improved, and the generation rate of the titanium dioxide is improved. Meanwhile, the generation of aluminum trichloride and the preheating treatment of titanium tetrachloride are organically combined, so that the production cost of titanium dioxide is obviously reduced.
S300: first preheating of oxygen
The dimethyl ether is combusted to provide heat, and the oxygen is subjected to first preheating treatment, so that the oxygen subjected to the first preheating treatment can be obtained. The manner of performing the first preheating treatment on the oxygen according to the embodiment of the present invention is not particularly limited, and according to the embodiment of the present invention, the first preheating treatment on the oxygen may be performed by using heat generated by combustion of dimethyl ether in an indirect heating manner. According to an embodiment of the present invention, the temperature of the oxygen gas subjected to the first preheating treatment is not particularly limited, and according to a specific embodiment of the present invention, the temperature of the oxygen gas subjected to the first preheating treatment is not lower than 750 ℃. Thereby, the oxidation efficiency can be significantly improved to further reduce the production cost of titanium dioxide.
S400: second preheating of oxygen
And providing heat by burning the toluene, and carrying out second preheating treatment on the oxygen subjected to the first preheating treatment, so that the oxygen subjected to the second preheating treatment can be obtained. According to an embodiment of the present invention, the temperature of the oxygen gas subjected to the second preheating treatment is not particularly limited, and according to a specific embodiment of the present invention, the temperature of the oxygen gas subjected to the second preheating treatment is not lower than 1500 degrees celsius. The manner of performing the second preheating treatment on the oxygen gas subjected to the first preheating treatment according to an embodiment of the present invention is not particularly limited, and according to an embodiment of the present invention, toluene may be mixed with the oxygen gas subjected to the first preheating treatment and combusted to emit heat to perform the second preheating treatment on the oxygen gas subjected to the first preheating treatment. Therefore, the oxidation efficiency can be obviously improved, and the production cost of the titanium dioxide is further reduced.
S500: oxidation reaction
And mixing the mixture of the aluminum trichloride and the titanium tetrachloride obtained through the second preheating treatment and the oxygen subjected to the second preheating treatment in an oxidation reaction device to enable the titanium tetrachloride and the oxygen to generate oxidation reaction, and adding silicon dioxide serving as scar removing sand into the oxidation reaction device, so that an oxidation reaction mixture containing titanium dioxide and chlorine can be obtained. In this step, the oxidation reaction equation is: TiCl (titanium dioxide)4+O2=TiO2+2Cl2。
S600: gas-solid separation treatment
The oxidation reaction mixture is subjected to gas-solid separation treatment, so that titanium dioxide and chlorine can be obtained.
Specifically, referring to fig. 2, the oxidation reaction mixture obtained is first rapidly cooled with circulating water, and the conditions for cooling the oxidation reaction mixture are not particularly limited according to the embodiment of the present invention, and the oxidation reaction mixture is rapidly cooled to 500 degrees celsius or less within 1 minute with circulating water according to the embodiment of the present invention. Thus, the titanium dioxide crystals can be prevented from growing and sticking to each other at high temperatures. And then carrying out gas-solid separation treatment on the cooled oxidation reaction mixture by using a bag filter, thereby obtaining gas tail gas containing chlorine and a solid mixture containing titanium dioxide and scar removing sand. Adding the solid mixture containing titanium dioxide and scar removing sand into a base material pulping tank, and adding demineralized water into the base material pulping tank for pulping.
And adding the obtained slurry into a scar removing sand separating device through a scar removing sand continuous feeding device, so that the scar removing sand reclaimed material and the titanium dioxide slurry can be separated and obtained. Specifically, a cylindrical sieve which can continuously run and has a washing function is adopted, so that solid particles are continuously separated, the abrasion is small, a vibrating sieve is not adopted, the aperture of a sieve pore is 350-450 micrometers, the solid content of slurry in a post-treatment process is required in the separation process, the water consumption of the washing agent cannot be too large in the separation process, and meanwhile, a small amount of titanium dioxide base material is remained on the surface of the scab removing sand separated from the base material through the scab removing sand sieve, so that the separated scab removing sand is conveyed to a scab removing sand washing system through a screw to be washed again by deionized water; the sand that will follow the scar removal sand drum sieve and carry in the operation process is sent into sand washing tank by screw conveyer, and the screen cloth is installed to the bottom of washing tank to be connected with the wash water system, be equipped with four rinse systems that height can be adjusted along the upper portion of washing tank, can ensure like this that the sand layer on washing tank surface can wash fully, the last washing after the upper portion is washed and is got into deionized water by the wash water system of washing tank bottom and wash the sand, the water yield carries out automatic control through flowmeter actual technology condition. The washed sand is accumulated in the sand washing tank, and in order to control the feeding and discharging conditions of the sand, the system is also provided with an automatic control system which controls the material level (discharging point) of the sand in the sand washing tank, so that when the sand layer reaches the discharging point, the control system can discharge the sand through the discharging screw while interrupting the feeding of the sand. When unloading, the sand can not be unloaded completely, and a certain sand layer thickness should be reserved at the bottom of the washing tank. The thickness of the sand layer may depend on the type of washer, and is typically 40-55 mm.
And carrying out steam drying treatment on the obtained recovered scar removing sand, thereby obtaining the dried scar removing sand. Concretely, the scar removing sand that separates out from scar removing sand lotion system is the wet scar removing sand of water content 20%, carry the main part through the spiral and be the gyration drum and in the desiccator of being provided with the multilayer heating pipe in the section of thick bamboo, the material in the desiccator is along with the rotation of barrel, constantly promotes, the raise and spill, through convection current, conduction, multiple heat transfer modes such as radiation are dried, and remove from higher one end to lower one end with the help of the inclination of desiccator, the final moisture content is less than 0.3% and is discharged by the ejection of compact rotary valve of desiccator afterbody. Meanwhile, the steam releases heat in the drying process to form condensed water, and the condensed water is discharged into a condensed water pipe network through a drain valve for recycling.
And returning the obtained dried scar removing sand to the oxidation reaction device, specifically, after the dried scar removing sand is discharged from the drying machine, the dried scar removing sand enters a dry sand storage bin through a belt conveyor and a bucket elevator, crushed sand with the particle size smaller than 0.7mm is separated from the dry sand through a sand separator, and the dry sand with the particle size of 0.7mm < d < 1.2mm is returned to the scar removing sand charging system for recycling. In addition, the waste gas discharged from the dryer contains certain dust, and in order to meet the environmental requirements, a bag type dust collector is arranged in the process system, the waste gas is discharged after dust removal through a draught fan, and the collected dust is discharged through a rotary valve at the lower part of the bag type dust collector.
A continuous feeding apparatus 100 for scab removing sand used in the method for preparing titanium dioxide according to an embodiment of the present invention will be described with reference to fig. 3. As shown in fig. 3, the continuous feeding apparatus 100 includes: the feeding device 10, the feeding bucket 20, the blowing bucket 30 and the feeding screw device 40.
Specifically, the charging bucket 20 is provided downstream of the charging device 10, and a first tank lock 51 for turning on and off the charging device 10 and the charging bucket 20 is provided between the charging device 10 and the charging bucket 20. The charging bucket 20 is provided with a sensor 23 for detecting the material capacity, and the sensor 23 is electrically connected with the first canning lock 51. Wherein, the inductor 23 is provided with a minimum material level and a maximum material level, and the inductor 23 is controlled by an electric pneumatic device. When the material on the charging bucket 20 is located at the minimum material level on the sensor 23, the sensor 23 feeds back insufficient material information to the electro-pneumatic device, the electro-pneumatic device sends a signal for unlocking the first canning lock 51, the first canning lock 51 conducts a communication pipeline between the charging device 10 and the charging bucket, and the material flows into the charging bucket from the charging device 10; when the material in the charging bucket 20 is at the maximum level on the sensor 23, the sensor 23 feeds back the information that the material is full to the electro-pneumatic device, and the first tank lock 51 cuts off the communication pipe between the charging device 10 and the charging bucket. The material may be a mixture of fixed particles of scar removing sand.
The blowing material tank 30 is arranged at the downstream of the feeding material tank 20, and a second tank lock 52 for communicating and cutting off the blowing material tank 30 and the feeding material tank 20 is arranged between the feeding material tank 20 and the blowing material tank 30. The feeding screw device 40 is arranged at the downstream of the blowing material tank 30, and the feeding screw device 40 is provided with a material outlet. Wherein, the inlet end of the blowing charging bucket 30 is connected with the outlet end of the charging bucket 20. When the material in the feed tank 20 has been filled, the second canister lock 52 may be opened, and the second canister lock 52 opens the communication between the feed tank 20 and the blowing tank 30, and the material begins to flow into the blowing tank 30. The material is uniformly blown in the blowing charging bucket 30 and then enters the feeding screw device 40. The material is further broken up into fine particles in the feed screw 40 and continuously sprayed from the material outlet into the oxidation reactor to remove the titanium oxide scabs on the inner wall of the oxidation reactor. Wherein, the blowing bucket 30 and the feeding screw device 40 are always conducted. In other words, the solid particles of the scab removing sand can be continuously conveyed into the oxidation reactor to ensure that the titanium chloride oxidation system normally and stably operates.
According to the continuous feeding device 100 for the scar removing sand adopted in the method for preparing titanium dioxide of the embodiment of the invention, the scar removing sand can be continuously sprayed into the oxidation reactor to remove titanium oxide scars on the inner wall of the oxidation reactor, so that the normal and stable operation of the titanium chloride oxidation system under the condition of uniform heating is ensured.
According to some embodiments of the present invention, the feed screw 40 is provided with a gas inlet 41 for introducing gas into the feed screw 40. The introduced gas converts the scab removing sand solid particles into a mixture of the fluidized matters and the gas with the same high-low density, and the mixture is uniformly sprayed into the oxidation reactor under high pressure. Wherein the gas may be nitrogen. Of course, the invention is not limited thereto, and the gas may be other inert gases.
In some embodiments of the present invention, the continuous feeding device 100 may further include a gas driving device 11. The gas driving device 11 is provided on the charging device 10 to drive the charging device 10 to supply the material to the charging bucket 20. Alternatively, the scar removing sand is transported in big bags. Wherein the charging device 10 may be a hopper (not shown) with an open upper end. The inlet end of the charging hopper is larger than the outlet end, which is beneficial to the material flowing to the charging bucket 20. In this way, in the case where the first tank lock 51 and the gas driving device 11 are simultaneously turned on, the material in the hopper can flow toward the material charging bucket 20 to achieve the feeding of the material charging bucket 20.
It should be noted that the feeding device 10 may also be a feeding bin 22, the feeding bin 22 is a closed shell relative to the outside, and further, an exhaust valve 21 may be disposed on the feeding tank 20, so that when the pressure in the feeding tank 20 is relatively high, the exhaust valve 21 may be opened to reduce the pressure in the feeding tank 20, thereby facilitating the material to flow from the feeding bin 22 into the feeding tank 20.
According to further embodiments of the present invention, the continuous feed apparatus 100 may further comprise a fluidization cone 60. The fluidization cone 60 is disposed below the charging bucket 20 and the blowing bucket 30. The bottom of the fluidization cone 60 can be provided with an air inlet valve, and during the charging process of the charging bucket 20, the air inlet valve can be opened, and air enters the charging bucket 20 and surrounds the material particles, so that the fluidization of the material is preliminarily realized. The material after primary fluidization flows out from the outlet end of the feeding bucket 20 and enters the blowing bucket 30, and the fluidization cone 60 fluidizes the material again, so that a mixture of the fluidized substance and the gas with high-low density is obtained.
Further, the continuous feeding device 100 may further include: a pressure regulating device 31 and a flow control device 80. The pressure adjusting device 31 is provided in the blowing bucket 30 to adjust the pressure in the blowing bucket 30. For example, when the pressure in the blowing bucket 30 is large, the pressure in the blowing bucket 30 can be reduced by the pressure adjusting device 31 so that the pressure in the blowing bucket 30 is smaller than the pressure in the charging bucket 20, thereby facilitating the flow of the material into the blowing bucket 30 by the gravity.
The flow control device 80 is provided downstream of the supply port of the blowing bucket 30 and serves to adjust the flow rate of the material supplied to the feed screw 40. The inlet end of the flow control device 80 is connected with the blowing bucket 30, and the outlet end of the flow control device 80 is connected with the feeding screw device 40. Wherein, preset material flow rate values are preset in the flow control device 80, and the ranges of the preset values can be as follows: 20-40 kg/h. For example, when the reaction material in the oxidation reactor is small, the flow rate may be set to 20 kg/h; when the reaction material in the oxidation reactor is at an intermediate amount, the flow rate may be set to 30 kg/h; when the reaction material in the oxidation reactor is large, the flow rate may be set to 40 kg/h. Of course, the present invention is not limited thereto.
The following describes the operation of the continuous feeding apparatus 100 for scarred sand used in the method for preparing titanium dioxide according to the embodiment of the present invention, opening the gas driving means 11 and the first canning lock 51, the material flows toward the feeding tank 20 by the driving of the gas driving means 11 while the gas introduced from the fluidization cone 60 flows upward in the opposite direction to the flow of the material, thereby ensuring that the material is sufficiently fluidized, and closing the first canning lock 51 when the sensor 23 detects that the inside of the feeding tank 20 is full; then the second canning lock 52 and the fluidization cone 60 are opened, the material flows from the feeding bucket 20 to the blowing bucket 30, the material is further fluidized, and a mixture of a fluidized substance and gas after sufficient fluidization is obtained; the flow rate of the mixture entering the feeding screw device 40 is controlled by adjusting the flow control device 80, and the mixture is sprayed into the oxidation reactor from the outlet of the feeding screw device 40 after being mixed with nitrogen in the feeding screw device 40 to form larger air pressure, so that the titanium oxide scabs in the oxidation reactor are removed. When the sensor 23 detects that the material in the feed tank 20 is less than or equal to the minimum level, the charging process of the feed tank 20 can be restarted, and in the process, if the pressure in the feed tank 20 is greater than the pressure in the charging device 10, the pressure in the feed tank 20 can be reduced by opening the exhaust valve 21 on the feed tank 20. Of course, the above process is only the basic process of the continuous feeding device 100, and the adjustment can be made in the actual production process.
According to the method for preparing titanium dioxide, the raw materials for titanium tetrachloride oxidation reaction can be effectively and rapidly preheated, and aluminum trichloride is obtained, so that titanium dioxide with uniform particle size can be effectively generated, the efficiency for preparing titanium dioxide can be improved, and meanwhile, the recycling of scar removing sand is realized through the method, so that the cost for preparing titanium dioxide is remarkably reduced.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (5)
1. A method of producing titanium dioxide, comprising:
(1) providing heat by burning dimethyl ether to carry out first preheating on titanium tetrachloride;
(2) mixing aluminum powder, chlorine and the titanium tetrachloride subjected to the first preheating in an aluminum trichloride generator, and reacting the aluminum powder and the chlorine to generate aluminum trichloride so as to obtain a mixture containing the aluminum trichloride and the titanium tetrachloride, wherein the titanium tetrachloride is subjected to second preheating by heat generated by the reaction of the aluminum powder and the chlorine, and the molar ratio of the aluminum powder to the chlorine is 1: 1-1: 5;
(3) providing heat by burning dimethyl ether to carry out first preheating on oxygen;
(4) providing heat by burning toluene, and carrying out secondary preheating on the oxygen subjected to the primary preheating;
(5) mixing the mixture containing aluminum trichloride and titanium tetrachloride obtained in the step (2) with the oxygen obtained in the step (4) after the second preheating in an oxidation reaction device, and allowing titanium tetrachloride and oxygen to undergo an oxidation reaction, wherein silica is added to the oxidation reaction device as scar removing sand, so as to obtain an oxidation reaction mixture containing titanium dioxide and chlorine; and
(6) carrying out gas-solid separation treatment on the oxidation reaction mixture so as to respectively obtain titanium dioxide and chlorine,
wherein,
the gas-solid separation treatment of the oxidation reaction mixture further comprises:
rapidly cooling the oxidation reaction mixture by using circulating water;
carrying out gas-solid separation treatment on the oxidation reaction mixture by using a bag filter so as to respectively obtain gas tail gas containing chlorine and a solid mixture containing titanium dioxide and scar removing sand;
adding the solid mixture to a base stock pulping tank, and pulping by adding demineralized water to the base stock pulping tank; and
adding the obtained slurry into a scar removing sand separating device so as to separate and obtain a scar removing sand reclaimed material and a titanium dioxide slurry;
washing and steam drying the recovered scar-removing sand to obtain dried scar-removing sand; and
and returning the dried scar-removing sand to the oxidation reaction device.
2. The method of claim 1, wherein the temperature of the first preheated titanium tetrachloride is not less than 270 degrees celsius;
the temperature of the titanium tetrachloride subjected to the second preheating is not lower than 350 ℃;
the temperature of the oxygen subjected to the first preheating is not lower than 750 ℃;
the temperature of the oxygen subjected to the second preheating is not lower than 1500 ℃.
3. The method of claim 1, wherein the first preheating of titanium tetrachloride and the first preheating of oxygen in step (1) and step (3) are indirect heating,
in step (4), toluene is mixed with the first preheated oxygen and combusted to perform second preheating of the first preheated oxygen by direct heating.
4. The method of claim 1, wherein in step (2), the aluminum powder and the chlorine gas are mixed in a ratio of 1: 1-1: 5 mol ratio, so that the proportion of the aluminum trichloride is 0.01-1% in the mixture containing the aluminum trichloride and the titanium tetrachloride.
5. The method of claim 1, wherein in step (6), the oxidation reaction mixture is rapidly cooled to below 500 degrees Celsius in 1 minute using circulating water.
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| CN111019403A (en) * | 2020-01-03 | 2020-04-17 | 河南佰利联新材料有限公司 | Preparation method of surface-modified titanium dioxide pigment |
| CN111874943A (en) * | 2020-06-22 | 2020-11-03 | 河南佰利联新材料有限公司 | Control method for CO content in boiling chlorination reaction tail gas |
| CN114573023A (en) * | 2022-03-31 | 2022-06-03 | 龙佰禄丰钛业有限公司 | Recycling method and system of oversize titanium dioxide base material |
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| CN107697949A (en) * | 2017-11-13 | 2018-02-16 | 龙蟒佰利联集团股份有限公司 | A kind of sulfuric acid process falls kiln product and is used for the production process of titanium pigment that chloridising removes scar sand |
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| CN111874943B (en) * | 2020-06-22 | 2023-04-07 | 河南佰利联新材料有限公司 | Control method for CO content in boiling chlorination reaction tail gas |
| CN114573023A (en) * | 2022-03-31 | 2022-06-03 | 龙佰禄丰钛业有限公司 | Recycling method and system of oversize titanium dioxide base material |
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