Production method of special titanium dioxide primary product

Abstract

The invention provides a production method of a special titanium dioxide primary product. The production method comprises the following steps: S1, preparing titanium tetrachloride mixed gas and adding the titanium tetrachloride mixed gas into a reaction unit; s2, enabling the titanium tetrachloride mixed gas to be in contact with oxygen and liquid potassium chloride in a reaction unit for reaction to generate a titanium dioxide primary product; s3, cooling the titanium dioxide primary product, and adding scar removing sand and silicon halide in sequence in the cooling process; and S4, cooling the primary titanium dioxide product, carrying out gas-solid separation, and collecting the primary special titanium dioxide product. According to the production method of the special titanium dioxide primary product, the basic performance of the titanium dioxide primary product is optimized, meanwhile, the content of aluminum in crystal lattices of the titanium dioxide primary product is increased, and the surface of the titanium dioxide primary product is coated with a layer of silicon dioxide, so that the weather resistance of the titanium dioxide primary product is improved, and the special titanium dioxide primary product with better basic performance and weather resistance is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chlorination titanium dioxide, in particular to a production method of special titanium dioxide. BACKGROUND

[0002] Chlorination and sulfuric acid method are the mainstream process for producing titanium dioxide at present. The chlorination method has become the main trend of titanium dioxide development because of its high degree of automation, advanced technology, high quality and environmental protection. In the production process of chlorination titanium dioxide, gaseous titanium tetrachloride is mixed with oxygen at 1600-2000℃ to generate titanium dioxide in a short time. After the titanium dioxide is coated and treated, titanium dioxide that meets the needs of different fields is prepared.

[0003] In recent years, with the increasing demand for titanium dioxide performance in various application fields, the demand for special titanium dioxide is becoming more and more urgent, especially high weather resistance titanium dioxide. In addition to the optimization of coating and post-treatment process, the quality improvement of titanium dioxide is also very important.

[0004] Based on the above background, the present application is proposed to improve the quality of titanium dioxide to meet the market demand for special titanium dioxide. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a production method of special titanium dioxide, which can optimize the basic performance of titanium dioxide, increase the content of aluminum in the titanium dioxide crystal lattice, and coat a layer of silicon dioxide on the surface of titanium dioxide to improve the weather resistance of titanium dioxide, thereby obtaining special titanium dioxide with better basic performance and weather resistance.

[0006] In order to achieve the above purpose of the present application, the following technical scheme is adopted: A production method of special titanium dioxide, comprising the following steps: Step S1, preparing titanium tetrachloride mixed gas and adding it to a reaction unit; Step S2, contacting the titanium tetrachloride mixed gas with oxygen and liquid potassium chloride in the reaction unit to generate titanium dioxide; Step S3, cooling the titanium dioxide, and adding scar sand and halogenated silicon in sequence during the cooling process; Step S4, performing gas-solid separation on the cooled titanium dioxide to collect special titanium dioxide.

[0007] Further, the production method of the special titanium dioxide crude product adopts a production system of the special titanium dioxide crude product, the production system of the titanium dioxide crude product sequentially comprises a titanium tetrachloride preheater 1, an aluminum trichloride generator 2, a reaction unit, a cooling conduit 5, and a gas-solid separation device 8 from front end to rear end; the reaction unit is a feeding ring 4; the front end of the feeding ring 4 further comprises a pre-combustion chamber 3 connected in parallel with the titanium tetrachloride preheater 1 and the aluminum trichloride generator 2; the rear end of the feeding ring 4 is connected with the cooling conduit 5, and the front end to the rear end of the pipeline of the cooling conduit 5 is sequentially provided with a scar sand adding port 6 and a halogenated silicon adding port 7.

[0008] Further, in step S1, the titanium tetrachloride is preliminarily preheated to 350-420℃ in the titanium tetrachloride preheater 1, and then mixed with aluminum trichloride in the aluminum trichloride generator 2, and then preheated to 450-520℃ after mixing, to obtain a titanium tetrachloride / aluminum trichloride mixed gas; the temperature difference between the titanium tetrachloride preheater 1 and the aluminum trichloride generator 2 is 80-100℃.

[0009] Further, in step S1, the titanium tetrachloride / aluminum trichloride mixed gas is introduced into the feeding ring 4.

[0010] Further, in step S1, the flow rate of the titanium tetrachloride introduced into the titanium tetrachloride preheater is 20-30t / h.

[0011] Further, in step S1, the content of aluminum in the titanium tetrachloride / aluminum trichloride mixed gas after mixing of the titanium tetrachloride gas with aluminum trichloride is controlled to be 1-2% of the mass of the titanium tetrachloride.

[0012] Further, in step S2, oxygen and liquid potassium chloride are mixed and heated in the pre-combustion chamber 3, and then introduced into the feeding ring 4, the preheating temperature of the oxygen in the pre-combustion chamber 3 is 1500-1900℃, the concentration of the liquid potassium chloride is 2-10g / L, and the flow rate is 10-80L / h.

[0013] Further, in step S3, the titanium dioxide crude product is introduced into the cooling conduit 5, and during the cooling process, scar sand is added into the cooling conduit 5 through the scar sand adding port 6, and halogenated silicon is added into the cooling conduit 5 through the halogenated silicon adding port 7, and the temperature at the halogenated silicon adding port 7 is 600-700℃.

[0014] Further, in step S3, the addition amount of the scar sand is 3%-6% of the mass of the titanium dioxide crude product generated in step S2.

[0015] Further, in step S3, the halogenated silicon is at least one of silicon tetrachloride, silicon tetrabromide, and silicon iodide.

[0016] Further, the distance between the scar sand adding port 6 and the pipeline of the feeding ring 4 is 500-800mm.

[0017] Further, the distance between the silicon halide adding port 7 and the pipeline of the feeding ring 4 is 4000-5000mm.

[0018] Further, the silicon halide adding ports 7 are distributed along the same cross section of the cooling conduit 5.

[0019] Further, the titanium white powder product after cooling in step S4 enters the gas-solid separation device 8 at 190-230 DEG C, and the special titanium white powder product is collected after separation.

[0020] Further, the production system of the titanium white powder product further comprises an online detection system 9 and a beating tank 10, and the online detection system 9 is arranged between the gas-solid separation device 8 and the beating tank 10.

[0021] Further, the production method of the special titanium white powder product further comprises: step S5, beating the collected special titanium white powder product, performing online monitoring on the basic performance of the special titanium white powder product through the online detection system 9, and adjusting process parameters according to the basic performance data.

[0022] Further, the adjusted process parameters in step S5 include at least one of the temperature of the titanium tetrachloride preheater 1, the temperature difference between the titanium tetrachloride preheater 1 and the aluminum chloride generator 2, the preheating temperature of oxygen, the adding amount of scar sand, and the adding amount of potassium chloride.

[0023] Compared with the prior art, the present application has the following beneficial effects: 1. The production method of the special titanium white powder product optimizes the basic performance of the titanium white powder product, increases the content of aluminum in the titanium white powder product lattice, and coats a layer of silicon dioxide on the surface of the titanium white powder product to improve the weather resistance of the titanium white powder product, so that a special titanium white powder product with better basic performance and weather resistance is obtained, which meets the market demand for special titanium white powder products.

[0024] 2. The production method of the special titanium white powder product adjusts the preheating temperature of titanium tetrachloride and oxygen, controls the temperature difference between the titanium tetrachloride preheater and the aluminum chloride generator, adjusts the reaction temperature of titanium tetrachloride and oxygen, significantly increases the content of aluminum Al in the titanium white powder lattice, and reduces the lattice defects, which are active sites of photocatalytic reaction. The reduction of defects can directly weaken the photochemical activity of titanium white powder. The lattice aluminum inhibits the phase light activity, and the surface coating of SiO2 blocks the direct contact between titanium dioxide and the environment, so that the weather resistance is improved under the synergistic action of the double mechanisms.

[0025] 3. The production method of the special titanium dioxide product of the present application, by setting a silicon halide adding port at a distance of 4000-5000 mm from the feeding ring, and controlling the temperature at the silicon halide adding port to be 600-700℃, to ensure that the silicon halide is hydrolyzed into silicon dioxide and coated on the surface of the titanium dioxide product.

[0026] 4. The present application adopts an online detection system to obtain the basic performance of the titanium dioxide product, such as particle size, particle size distribution, and whiteness, in time, and combines the interlocking control of the online control system and the related previous process section to timely adjust the related process parameters, to ensure the qualified rate of the titanium dioxide product. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0028] Figure 1 The structural diagram of the production system of the special titanium dioxide product (not containing the online detection system) adopted by the production method of the special titanium dioxide product of the present application; Figure 2 The structural diagram of the production system of the special titanium dioxide product (containing the online detection system) adopted by the production method of the special titanium dioxide product of the present application.

[0029] Explanation of reference numerals: 1-titanium tetrachloride preheater, 2-aluminum trichloride generator, 3-precombustion chamber, 4-feeding ring, 5-cooling guide pipe, 6-scar sand adding port, 7-silicon halide adding port, 8-gas-solid separation equipment, 9-online detection system, 10-beating tank. DETAILED DESCRIPTION

[0030] The technical solutions of the present application will be described in detail below in combination with specific embodiments, but those skilled in the art will understand that the following described embodiments are part of the embodiments of the present application, not all the embodiments, and are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application. The specific conditions not mentioned in the embodiments are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments not mentioned by the manufacturer are all conventional products that can be purchased on the market.

[0031] A production method of a special titanium dioxide product, comprising the following steps: Step S1, titanium tetrachloride mixed gas is added into the reaction unit; Step S2, the titanium tetrachloride mixed gas is contacted with oxygen and liquid potassium chloride in the reaction unit to generate titanium dioxide primary product; Step S3, the titanium dioxide primary product is cooled, and scar sand and silicon halide are added in sequence during the cooling process; Step S4, the titanium dioxide primary product is separated after cooling to collect the special titanium dioxide primary product; Preferably, the production method of the special titanium dioxide primary product uses a special titanium dioxide primary product production system, which includes, from front to back, a titanium tetrachloride preheater 1, an aluminum trichloride generator 2, a reaction unit, a cooling conduit 5, and a gas-solid separation device 8. The reaction unit is a feeding ring 4. The front end of the feeding ring 4 also includes a pre-combustion chamber 3 connected in parallel with the titanium tetrachloride preheater 1 and the aluminum trichloride generator 2. The rear end of the feeding ring 4 is connected to the cooling conduit 5, and the front end to the rear end of the pipeline of the cooling conduit 5 is sequentially provided with a scar sand addition port 6 and a silicon halide addition port 7; Preferably, in step S1, the titanium tetrachloride is initially preheated in the titanium tetrachloride preheater 1, then mixed with aluminum trichloride in the aluminum trichloride generator 2, and then preheated again to obtain titanium tetrachloride / aluminum trichloride mixed gas; Preferably, in step S1, the titanium tetrachloride / aluminum trichloride mixed gas is introduced into the feeding ring 4; Preferably, in step S1, the titanium tetrachloride is initially preheated to 350-420℃ in the titanium tetrachloride preheater 1, including but not limited to 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, and 420℃; Preferably, in step S1, the aluminum trichloride generator 2 is preheated to a temperature of 450-520℃, including but not limited to 450℃, 460℃, 470℃, 480℃, 490℃, 500℃, 510℃, and 520℃; Preferably, in step S1, the temperature difference between the titanium tetrachloride preheater 1 and the aluminum trichloride generator 2 (i.e., the temperature difference between the initial preheating temperature of the titanium tetrachloride gas and the preheating temperature of the titanium tetrachloride / aluminum trichloride mixed gas) is 80-100℃, including but not limited to 80℃, 85℃, 90℃, 95℃, and 100℃; Preferably, in step S1, the flow rate of the titanium tetrachloride introduced into the titanium tetrachloride preheater is 20-30t / h, including but not limited to 20t / h, 21t / h, 22t / h, 23t / h, 24t / h, 25t / h, 26t / h, 27t / h, 28t / h, 29t / h, and 30t / h; Preferably, the content of aluminum in the titanium tetrachloride / aluminum chloride mixed gas after mixing the titanium tetrachloride gas with the aluminum chloride in step S1 is controlled at 1-2% of the mass of the titanium tetrachloride, including but not limited to 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%; Preferably, the oxygen and the liquid potassium chloride are mixed and heated in the pre-combustion chamber 3 and then introduced into the feeding ring 4 in step S2. Preferably, the titanium tetrachloride / aluminum chloride mixed gas is contacted with the oxygen and the liquid potassium chloride in the feeding ring 4 to generate the titanium dioxide crude product in step S2. Preferably, the preheating temperature of the oxygen in the pre-combustion chamber 3 is 1500-1900°C, including but not limited to 1500°C, 1600°C, 1700°C, 1800°C, 1900°C, the concentration of the liquid potassium chloride is 2-10 g / L, including but not limited to 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, and the flow rate is 10-80 L / h, including but not limited to 10 L / h, 20 L / h, 30 L / h, 40 L / h, 50 L / h, 60 L / h, 70 L / h, 80 L / h. The preheating temperature of the titanium tetrachloride and the oxygen is adjusted, and the temperature difference between the titanium tetrachloride preheater and the aluminum chloride generator is controlled to adjust the reaction temperature of the titanium tetrachloride and the oxygen, thereby increasing the content of Al in the titanium dioxide lattice. Preferably, the titanium dioxide crude product is introduced into the cooling conduit 5 in step S3, and the scar sand is added to the cooling conduit 5 through the scar sand adding port 6 and the halogenated silicon is added to the cooling conduit 5 through the halogenated silicon adding port 7 during the cooling process. Preferably, the distance between the scar sand adding port 6 and the pipeline of the feeding ring 4 is 500-800 mm, including but not limited to 500 mm, 550 mm, 600 mm, 650 mm, 700 mm, 750 mm, 800 mm. Preferably, the amount of the scar sand added in step S3 is 3%-6% of the mass of the titanium dioxide crude product generated in step S2, including but not limited to 3%, 4%, 5%, 6%. Preferably, the halogenated silicon in step S3 is at least one of silicon tetrachloride, silicon tetrabromide, and silicon iodide. Preferably, the distance between the halogenated silicon adding port 7 and the pipeline of the feeding ring 4 is 4000-5000 mm, including but not limited to 4000 mm, 4100 mm, 4200 mm, 4300 mm, 4400 mm, 4500 mm, 4600 mm, 4700 mm, 4800 mm, 4900 mm, 5000 mm. Preferably, the plurality of silicon halide addition ports 7 are distributed circumferentially along the same cross-section of the cooling conduit 5; Preferably, the three silicon halide addition ports 7 are evenly distributed circumferentially along the same cross-section of the cooling conduit 5 with an interval angle of 120°; Preferably, the temperature at the silicon halide addition port 7 in step S3 is 600-700°C, including but not limited to 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C, and 700°C. The temperature at the silicon halide addition port 7 is controlled by controlling the flow rate of the cooling medium and the inlet and outlet temperatures of the cooling medium; By setting the silicon halide addition port at a distance of 4000-5000 mm from the feeding ring 4000 and controlling the temperature at the addition port to be 600-700°C, the hydrolysis of silicon halide to silicon dioxide and the coating of titanium dioxide on the surface of titanium dioxide are ensured; Preferably, the cooling medium is cooling water, and the cooling conduit is a jacketed structure. The cooling water is arranged in the outer peripheral cooling water pipe of the cooling conduit 5, and the jacketed structure is arranged outside the cooling conduit 5; Preferably, the flow rate of the cooling water is 130-150 m 3 / h, including but not limited to 130 m 3 / h, 135 m 3 / h, 138 m 3 / h, 140 m 3 / h, 142 m 3 / h, 145 m 3 / h, 150 m 3 / h, and the outlet temperature of the cooling water is controlled to be 60-75°C, including but not limited to 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, and 75°C; Preferably, after the titanium dioxide primary product is cooled in step S4, it is introduced into the gas-solid separation device 8, and the special titanium dioxide primary product is collected after separation; Preferably, after the titanium dioxide primary product is cooled in step S4, it is introduced into the gas-solid separation device 8 at a temperature of 190-230°C (including but not limited to 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, and 230°C); Preferably, the production system of the titanium dioxide primary product further comprises an online detection system 9 and a beating tank 10. The online detection system 9 is arranged between the gas-solid separation device 8 and the beating tank 10, and directly detects the dry powder of the titanium dioxide primary product; Preferably, the production method of the special titanium dioxide product further comprises: step S5, beating the collected special titanium dioxide product, and monitoring the basic performance of the special titanium dioxide product by the online detection system 9, and adjusting the process parameters according to the basic performance data; Preferably, the step S5 forms interlocking control of the online detection system 9, the online control system and the process parameters of the previous process section, so as to determine the basic performance of the titanium dioxide product at any time and adjust the process parameters in time; the online detection system 9 is used to obtain the basic performance of the titanium dioxide product, such as particle size, particle size distribution and whiteness, and through interlocking control with the previous process section, the related process parameters are adjusted in time to ensure that the basic performance of the titanium dioxide product is qualified; Preferably, the basic performance monitored in step S5 includes at least one of the particle size, the particle size distribution and the whiteness of the titanium dioxide product; Preferably, the process parameters adjusted in step S5 include at least one of the temperature of the titanium tetrachloride preheater 1, the temperature difference between the titanium tetrachloride preheater 1 and the aluminum trichloride generator 2, the preheating temperature of oxygen, the addition amount of scar sand and the addition amount of potassium chloride.

[0032] Embodiment 1 A production method of a special titanium dioxide product, comprising the following steps: a. The titanium tetrachloride is preheated to 410℃ and then introduced into the aluminum trichloride generator 2 to mix with aluminum trichloride and then preheated again. The titanium tetrachloride / aluminum trichloride mixed gas is introduced into the feeding ring 4 at 510℃, and the temperature difference between the two temperatures is 100℃. The flow rate of titanium tetrachloride introduced into the titanium tetrachloride preheater is set to 28t / h, and the content of aluminum in the titanium tetrachloride / aluminum trichloride mixed gas is controlled to be 1.8% of the mass of titanium tetrachloride; b. The oxygen preheated to 1800℃ is mixed with liquid potassium chloride and introduced into the feeding ring 4 to react with the titanium tetrachloride / aluminum trichloride mixed gas to generate the titanium dioxide product. The concentration of potassium chloride is set to 8g / L, and the flow rate is 30L / h; c. The titanium dioxide product enters the cooling conduit, the distance between the scar sand addition port 6 and the pipeline of the feeding ring 4 is 700mm, and the addition amount of scar sand is set to 5% of the mass of the titanium dioxide product generated in step b; d. The halogenated silicon is silicon tetrachloride, the distance between the halogenated silicon addition port 7 and the pipeline of the feeding ring 4 is 4500mm, and the flow rate of the cooling water in the cooling conduit is set to 142m 3 / h, the outlet temperature of the cooling water is 73℃, and at this time the temperature of the halogenated silicon addition port 7 where the silicon tetrachloride is added is 670℃; e. The titanium dioxide product enters the gas-solid separation device 8 at 200℃ after passing through the cooling conduit 5.

[0033] The particle size, particle size distribution and whiteness of the titanium dioxide crude product slurry are detected by the online detection system 9 arranged between the gas-solid separation device 8 and the beater tank 10.

[0034] The titanium dioxide crude product slurry in the beater tank is taken for treatment to measure the content of silicon in the crude product.

[0035] The titanium dioxide crude product slurry is taken, filtered and dried, and then heated in a hydrochloric acid solution (hydrochloric acid: water = 1:1) under a micro-boiling state for 60 min. The content of aluminum before and after heating is measured. The content of aluminum after heating is the content of lattice aluminum. The ratio of the content of aluminum after heating to the content of aluminum before heating is the proportion of lattice aluminum in the total aluminum in the crude product.

[0036] Example 2 A production method of a special titanium dioxide crude product, comprising the following steps: a. The titanium tetrachloride is preheated to 410℃ and then introduced into the aluminum chloride generator 2 to mix with aluminum chloride, and then preheated again. The titanium tetrachloride / aluminum chloride mixed gas is introduced into the feeding ring 4 at 500℃, and the temperature difference between the two temperatures is 90℃. The flow rate of titanium tetrachloride introduced into the titanium tetrachloride preheater is set to 28t / h, and the content of aluminum in the titanium tetrachloride / aluminum chloride mixed gas is controlled to be 1.6% of the mass of titanium tetrachloride; b. The oxygen preheated to 1800℃ is mixed with liquid potassium chloride and introduced into the feeding ring 4 to react with the titanium tetrachloride / aluminum chloride mixed gas to generate titanium dioxide crude product. The concentration of potassium chloride is set to 8g / L, and the flow rate is 30L / h; c. The titanium dioxide crude product enters the cooling conduit, the distance from the scabbing sand adding port 6 to the pipeline of the feeding ring 4 is 700mm, and the adding amount of the scabbing sand is set to 5% of the mass of the titanium dioxide crude product generated in step b; d. The halogenated silicon is silicon tetrachloride, the distance from the halogenated silicon adding port 7 to the pipeline of the feeding ring 4 is 4800mm, and the flow rate of the cooling water in the cooling conduit is set to 150m 3 / h, the outlet temperature of the cooling water is 73℃, and at this time the temperature of the halogenated silicon adding port 7 where the silicon tetrachloride is added is 640℃; e. The titanium dioxide crude product enters the gas-solid separation device 8 at 195℃ after passing through the cooling conduit 5.

[0037] The particle size, particle size distribution and whiteness of the titanium dioxide crude product slurry are detected by the online detection system 9 arranged between the gas-solid separation device 8 and the beater tank 10.

[0038] The titanium dioxide crude product slurry in the beater tank is taken for treatment to measure the content of silicon in the crude product.

[0039] Take the titanium dioxide initial product slurry, filter and dry, then heat the titanium dioxide initial product in hydrochloric acid solution (hydrochloric acid: water = 1:1) to keep it in a micro-boiling state for 60 min. Measure the aluminum content before and after heating. The aluminum content after heating is the content of lattice aluminum. The ratio of the aluminum content after heating to the aluminum content before heating is the proportion of lattice aluminum. Measure the proportion of aluminum in the lattice in the initial product in the total aluminum in the initial product.

[0040] Example 3 A production method of a special titanium white initial product, comprising the following steps: a. Preheat titanium tetrachloride to 410℃, then pass it into the generator 2 to mix with aluminum chloride, preheat again, pass the titanium tetrachloride / aluminum chloride mixed gas into the feeding ring 4 at 500℃, the temperature difference between the two is 90℃, set the flow rate of titanium tetrachloride into the preheater to be 25t / h, and control the aluminum content in the titanium tetrachloride / aluminum chloride mixed gas to be 1.8% of the mass of titanium tetrachloride; b. Mix oxygen preheated to 1600℃ with liquid potassium chloride into the feeding ring 4 to react with the titanium tetrachloride / aluminum chloride mixed gas to generate titanium white initial product; set the concentration of potassium chloride to be 10g / L, and the flow rate to be 50L / h; c. The titanium white initial product enters the cooling conduit, the distance from the scar sand adding port 6 to the pipeline of the feeding ring 4 is 600mm, and the addition amount of the scar sand is set to be 6% of the mass of the titanium white initial product generated in step b; d. The halogenated silicon is silicon tetrachloride, the distance from the halogenated silicon adding port 7 to the pipeline of the feeding ring 4 is 4800mm, and the flow rate of the cooling water in the cooling conduit is set to be 138m 3 / h, the outlet temperature of the cooling water is 68℃, and at this time the temperature of the halogenated silicon adding port 7 where the silicon tetrachloride is added is 640℃; e. The titanium white initial product passes through the cooling conduit 5 and enters the gas-solid separation equipment 8 at 190℃.

[0041] Through the online detection system 9 set between the gas-solid separation equipment 8 and the beating tank 10, the titanium white initial product slurry is sampled to detect the particle size, particle size distribution and whiteness of the titanium white initial product.

[0042] Take the titanium white initial product slurry in the beating tank for treatment and measure the content of silicon in the initial product.

[0043] Take the titanium dioxide initial product slurry, filter and dry, then heat the titanium dioxide initial product in hydrochloric acid solution (hydrochloric acid: water = 1:1) to keep it in a micro-boiling state for 60 min. Measure the aluminum content before and after heating. The aluminum content after heating is the content of lattice aluminum. The ratio of the aluminum content after heating to the aluminum content before heating is the proportion of lattice aluminum. Measure the proportion of aluminum in the lattice in the initial product in the total aluminum in the initial product.

[0044] Comparative Example 1 A production method of a special titanium dioxide primary product, comprising the following steps: a. The titanium tetrachloride is preheated to 340℃ and then introduced into the aluminum chloride generator 2 to mix with aluminum chloride, and then preheated again. The titanium tetrachloride / aluminum chloride mixed gas is introduced into the feeding ring 4 at 440℃, and the temperature difference between the two temperatures is 100℃. The flow rate of titanium tetrachloride introduced into the titanium tetrachloride preheater is set to 25t / h, and the aluminum content in the titanium tetrachloride / aluminum chloride mixed gas is controlled to be 1.8% of the mass of titanium tetrachloride; b. The oxygen preheated to 1600℃ is mixed with liquid potassium chloride and introduced into the feeding ring 4 to react with the titanium tetrachloride / aluminum chloride mixed gas to generate a titanium dioxide primary product. The concentration of potassium chloride is set to 10g / L, and the flow rate is 50L / h; c. The titanium dioxide primary product enters the cooling conduit, and the distance between the scabbing sand adding port 6 and the pipeline of the feeding ring 4 is 700mm. The amount of scabbing sand added is set to 6% of the mass of the titanium dioxide primary product generated in step b; d. The halogenated silicon is silicon tetrachloride. The distance between the halogenated silicon adding port 7 and the pipeline of the feeding ring 4 is 5200mm. The flow rate of the cooling water in the cooling conduit is set to 138m 3 / h, and the outlet temperature of the cooling water is 68℃. At this time, the temperature at the halogenated silicon adding port 7 where the silicon tetrachloride is added is 550℃; e. The titanium dioxide primary product enters the gas-solid separation device 8 at 184℃ after passing through the cooling conduit 5.

[0045] Through the online detection system 9 set between the gas-solid separation device 8 and the beating tank 10, the titanium dioxide primary product slurry is sampled to detect the particle size, particle size distribution and whiteness of the titanium dioxide primary product.

[0046] The titanium dioxide primary product slurry in the beating tank is taken for processing to measure the content of silicon in the primary product.

[0047] The titanium dioxide primary product slurry is taken, filtered and dried, and then heated in a hydrochloric acid solution (hydrochloric acid:water=1:1) while keeping it in a slightly boiling state for 60min. The aluminum content before and after heating is measured. The aluminum content after heating is the content of lattice aluminum. The ratio of the aluminum content after heating to the aluminum content before heating is the proportion of lattice aluminum in the total aluminum in the primary product.

[0048] Comparative Example 2 A production method of a special titanium dioxide primary product, comprising the following steps: a. The titanium tetrachloride is preheated to 370℃ and then introduced into the aluminum chloride generator 2 to mix with aluminum chloride, and then preheated again. The titanium tetrachloride / aluminum chloride mixed gas is introduced into the feeding ring 4 at 430℃, and the temperature difference between the two temperatures is 60℃. The flow rate of titanium tetrachloride introduced into the titanium tetrachloride preheater is set to 25t / h, and the aluminum content in the titanium tetrachloride / aluminum chloride mixed gas is controlled at 1.8% of the mass of titanium tetrachloride; b. The oxygen preheated to 1800℃ is mixed with liquid potassium chloride and introduced into the feeding ring 4 to react with the titanium tetrachloride / aluminum chloride mixed gas to generate titanium dioxide primary product. The concentration of potassium chloride is set to 10g / L, and the flow rate is 50L / h; c. The titanium dioxide primary product enters the cooling conduit, and the distance between the scar sand adding port 6 and the pipeline of the feeding ring 4 is 700mm. The addition amount of the scar sand is set to 5% of the mass of the titanium dioxide primary product generated in step b; d. The halogenated silicon is silicon tetrachloride. The distance between the halogenated silicon adding port 7 and the pipeline of the feeding ring 4 is 4800mm. The flow rate of the cooling water in the cooling conduit is set to 140m 3 / h, and the outlet temperature of the cooling water is 70℃. At this time, the temperature of the halogenated silicon adding port 7 where the silicon tetrachloride is added is 640℃; e. The titanium dioxide primary product passes through the cooling conduit 5 and enters the gas-solid separation device 8 at 200℃.

[0049] The on-line detection system 9 set between the gas-solid separation device 8 and the beating tank 10 is used to sample and detect the particle size, particle size distribution and whiteness of the titanium dioxide primary product.

[0050] The titanium dioxide primary product slurry in the beating tank is taken for treatment to measure the content of silicon in the primary product.

[0051] The titanium dioxide primary product slurry is taken, filtered and dried, and then heated in a hydrochloric acid solution (hydrochloric acid: water = 1:1) while keeping it in a slightly boiling state for 60min. The aluminum content before and after heating is measured. The aluminum content after heating is the content of lattice aluminum. The ratio of the aluminum content after heating to the aluminum content before heating is the proportion of lattice aluminum in the total aluminum in the primary product.

[0052] Detection results: The performance detection results of the special titanium dioxide primary product produced in Examples 1-3 and Comparative Examples 1-2 are shown in Table 1.

[0053] Table 1 Performance detection results of the special titanium dioxide primary product produced in Examples 1-3 and Comparative Examples 1-2

[0054] From Table 1, (1) the basic properties (particle size, particle size distribution and whiteness) of the titanium dioxide crude products produced by Examples 1-3 are qualified and superior to the basic properties of the titanium dioxide crude products produced by Comparative Examples 1-2, which indicates that under the process parameter conditions of the present application, the basic properties (particle size, particle size distribution and whiteness) of the titanium dioxide crude products can be effectively improved; (2) the present application uses a 60° gloss meter to measure the gloss retention rate of the titanium dioxide crude products before and after aging to determine the weather resistance, and the 36h 60° gloss retention rate of the titanium dioxide crude products produced by Examples 1-3 is significantly higher than the 36h 60° gloss retention rate of the titanium dioxide crude products produced by Comparative Examples 1-2, which indicates that under the process parameter conditions of the present application, the weather resistance of the titanium dioxide crude products can be significantly improved, and the market demand for special titanium dioxide crude products can be met.

Claims

1. A method for producing a special titanium dioxide primary product, characterized in that, Includes the following steps: Step S1: Prepare titanium tetrachloride mixed gas and add it to the reaction unit; Step S2: The titanium tetrachloride mixed gas is reacted with oxygen and liquid potassium chloride in the reaction unit to produce titanium dioxide primary product; Step S3: Cool the initial titanium dioxide product, adding descaling sand and silicon halide sequentially during the cooling process; Step S4: After cooling, the titanium dioxide primary product undergoes gas-solid separation to collect the special titanium dioxide primary product.

2. The method for producing the special titanium dioxide primary product according to claim 1, characterized in that, The production method of this special titanium dioxide primary product adopts a special titanium dioxide primary product production system, which includes a titanium tetrachloride preheater (1), an aluminum trichloride generator (2), a reaction unit, a cooling conduit (5), and a gas-solid separation device (8) from front end to back end. The reaction unit is a feeding ring (4); the front end of the feeding ring (4) also includes a pre-combustion chamber 3 connected in parallel with the titanium tetrachloride preheater (1) and the aluminum trichloride generator (2); The rear end of the feeding ring (4) is connected to the cooling conduit (5), and the front end of the cooling conduit (5) is provided with a descaling sand addition port (6) and a silicon halide addition port (7) in sequence.

3. The method for producing the special titanium dioxide primary product according to claim 2, characterized in that, Includes at least one of the following technical features: (A) In step S1, titanium tetrachloride is introduced into the titanium tetrachloride preheater (1) and preheated to 350~420°C. Then it is introduced into the aluminum trichloride generator (2) and mixed with aluminum trichloride. After mixing, it is preheated again to 450~520°C to obtain a titanium tetrachloride / aluminum trichloride mixed gas. The temperature difference between the titanium tetrachloride preheater (1) and the aluminum trichloride generator (2) is 80~100°C. (B) In step S1, the titanium tetrachloride / aluminum trichloride mixed gas is introduced into the feeding ring (4); (C) The flow rate of titanium tetrachloride introduced into the titanium tetrachloride preheater in step S1 is 20~30 t / h; (D) In ​​step S1, the aluminum content in the titanium tetrachloride / aluminum trichloride mixed gas after mixing titanium tetrachloride gas and aluminum trichloride is controlled to be 1~2% of the mass of titanium tetrachloride.

4. The method for producing the special titanium dioxide primary product according to claim 2, characterized in that, In step S2, oxygen and liquid potassium chloride are introduced into the pre-combustion chamber (3) and heated together before being introduced into the feeding ring (4). The preheating temperature of oxygen in the pre-combustion chamber (3) is 1500~1900℃, the concentration of liquid potassium chloride is 2~10g / L, and the flow rate is 10~80L / h.

5. The method for producing the special titanium dioxide primary product according to claim 2, characterized in that, Includes at least one of the following technical features: (A) The titanium dioxide raw material mentioned in step S3 enters the cooling conduit (5). During the cooling process, the descaling sand is added to the cooling conduit (5) through the descaling sand addition port (6), and silicon halide is added to the cooling conduit (5) through the silicon halide addition port (7). The temperature at the silicon halide addition port (7) is 600~700℃. (B) The amount of descaling sand added in step S3 is 3% to 6% of the initial mass of the titanium dioxide produced in step S2; (C) In step S3, the silicon halide is at least one of silicon tetrachloride, silicon tetrabromide, and silicon iodide.

6. The method for producing the special titanium dioxide primary product according to claim 2 or 5, characterized in that, Includes at least one of the following technical features: (A) The pipe distance between the scar removal sand addition port (6) and the feeding ring (4) is 500~800mm; (B) The pipe distance between the silicon halide addition port (7) and the feeding ring (4) is 4000~5000mm; (C) Multiple silicon halide addition ports (7) are circumferentially distributed along the same cross section of the cooling conduit (5).

7. The method for producing the special titanium dioxide primary product according to claim 2, characterized in that, In step S4, after the titanium dioxide primary product is cooled, it enters the gas-solid separation device (8) at 190~230℃, and the special titanium dioxide primary product is collected after separation.

8. The method for producing the special titanium dioxide primary product according to claim 2, characterized in that, The titanium dioxide primary product production system also includes an online detection system (9) and a pulping tank (10), wherein the online detection system (9) is located between the gas-solid separation equipment (8) and the pulping tank (10).

9. The method for producing the special titanium dioxide primary product according to claim 8, characterized in that, The production method of this special titanium dioxide primary product also includes: step S5, pulping the collected special titanium dioxide primary product, monitoring the basic performance of the special titanium dioxide primary product online through the online detection system (9), and adjusting the process parameters according to the basic performance data.

10. The method for producing the special titanium dioxide primary product according to claim 9, characterized in that, The process parameters adjusted in step S5 include at least one of the following: the temperature of the titanium tetrachloride preheater (1), the temperature difference between the titanium tetrachloride preheater (1) and the aluminum trichloride generator (2), the oxygen preheating temperature, the amount of descaling sand added, and the amount of potassium chloride added.

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