A continuous hydrolysis system and method for sulfuric acid process titanium dioxide

Abstract

The application discloses a continuous hydrolysis system for sulfuric acid method titanium dioxide, which comprises a hydrolysis device, a temperature control pipeline, a metatitanic acid storage tank and a steam pipeline, wherein the hydrolysis device comprises a first preheating tank, a second preheating tank, a third preheating tank, a hydrolysis crystal seed preparation tank and a continuous mixing tank, the bottoms of the first preheating tank and the second preheating tank are communicated with the top of the hydrolysis crystal seed preparation tank respectively, and the bottoms of the third preheating tank and the hydrolysis crystal seed preparation tank are communicated with the top of the continuous mixing tank respectively; a pipeline heater and a pipeline cooler are sequentially connected between a first pipe opening and a second pipe opening of the temperature control pipeline, the first pipe opening is communicated with the continuous mixing tank, and the metatitanic acid storage tank is communicated with the second pipe opening. The application further provides a continuous hydrolysis method. The system and the method can convert the intermittent titanium liquid hydrolysis process into a continuous production, greatly improve the production efficiency, reduce the labor intensity of operation, and are favorable to promote the full-automatic production of the sulfuric acid method titanium dioxide.

Description

Technical Field

[0001] This invention relates to the field of mixed titanium dioxide production technology, and in particular to a continuous hydrolysis system and method for sulfuric acid titanium dioxide. Background Technology

[0002] The hydrolysis of titanium solution is the process by which titanium dioxide components are transformed from the liquid phase (titanium solution) back into the solid phase (metatinic acid), thereby separating them from soluble impurities in the mother liquor to extract pure titanium dioxide.

[0003] Hydrolysis is one of the most crucial processes in the sulfuric acid process for titanium dioxide production. The quality of hydrolysis not only affects the economics of industrial production but also significantly impacts the quality of the final product. Errors caused during hydrolysis are often irreparable in subsequent processes. Industrially, hydrolysis requires the following: First, a high hydrolysis rate, meaning a high percentage of titanium dioxide in the liquid phase is converted to the solid phase. A higher hydrolysis rate is more economical without affecting the quality and performance of the finished product. Second, the hydrolysis products must be uniformly sized particles with a constant composition, and be easy to filter and wash. Third, the process conditions must be mature and easily controlled, the quality of the hydrolysis products must be stable, and the equipment must be simple and adaptable to industrial production needs. Currently, the hydrolysis process for titanium dioxide in the sulfuric acid process is done intermittently in batches. After each batch of hydrolysis, the hydrolysis pot needs to be cleaned. Incomplete cleaning will severely affect the quality of the next batch of hydrolyzed metatitanic acid. Therefore, production efficiency is low, the labor intensity is high, and product quality fluctuations are relatively large.

[0004] Therefore, there is a need for improvements to existing technologies regarding continuous hydrolysis systems and methods for titanium dioxide produced by the sulfuric acid process. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a continuous hydrolysis system and method for sulfuric acid process titanium dioxide. This method can transform the intermittent titanium liquid hydrolysis process into continuous production, which can significantly improve production efficiency, reduce the labor intensity of operation, and promote the fully automated production of sulfuric acid process titanium dioxide.

[0006] To achieve the above objectives, embodiments of the present invention provide a continuous hydrolysis system for titanium dioxide produced via the sulfuric acid process, comprising: a hydrolysis device, a temperature-controlled pipeline, a metatitanic acid storage tank, and a steam pipeline, wherein...

[0007] The hydrolysis device includes a first preheating tank, a second preheating tank, a third preheating tank, a hydrolysis seed preparation tank, and a continuous mixing tank. The bottoms of the first preheating tank and the second preheating tank are respectively connected to the top of the hydrolysis seed preparation tank, and the bottoms of the third preheating tank and the hydrolysis seed preparation tank are respectively connected to the top of the continuous mixing tank.

[0008] A pipe heater and a pipe cooler are connected sequentially between the first and second ports of the temperature control pipe. The first port is connected to the continuous mixing tank, and the metatitanic acid storage tank is connected to the second port.

[0009] Each tank in the hydrolysis unit is connected to a steam pipe for heating by steam.

[0010] In some embodiments, the system further includes a concentrated titanium liquid storage tank, which is connected to a first preheating tank and a third preheating tank respectively, and the concentrated titanium liquid is continuously delivered by a pressure pump.

[0011] In some embodiments, a first pipe heater, a second pipe heater, and a pipe cooler are sequentially arranged on the temperature control pipe, and the second pipe heater is further connected to the demineralized water pipe.

[0012] In some embodiments, the cooler is a graphite cooler.

[0013] In another aspect, the present invention provides a continuous hydrolysis method for titanium dioxide using the sulfuric acid process. The method is implemented through the above-mentioned system and includes the following steps:

[0014] Add alkaline solution to the second preheating tank;

[0015] Concentrated titanium liquid is continuously pumped into the first preheating tank and the third preheating tank through a concentrated titanium liquid storage tank. The concentrated titanium liquid in the first preheating tank and the alkaline solution in the second preheating tank flow into the hydrolysis seed preparation tank to prepare the hydrolysis seed solution. The concentrated titanium liquid in the third preheating tank and the hydrolysis seed solution in the hydrolysis seed preparation tank flow into the continuous mixing tank for continuous mixing to prepare the mixed solution. The temperature in each tank is controlled by a steam pipe.

[0016] The mixture flows continuously from the continuous mixing tank into the temperature-controlled pipeline, where it is initially heated in the first pipeline heater, then heated and diluted in the second pipeline heater, and finally cooled to the target temperature by the cooler before being stored in the metatitanic acid storage tank.

[0017] In some embodiments, the temperature in the first preheating tank and the second preheating tank is controlled at 96°C via a steam pipe, the temperature in the second preheating tank is controlled at 80-90°C, and the temperature in the hydrolysis seed crystal preparation tank is controlled at 95-98°C via a steam pipe.

[0018] In some embodiments, the outflow rate of concentrated titanium liquid in the first preheating tank is ν1, the outflow rate of alkaline solution in the second preheating tank is ν2, the outflow rate of concentrated titanium liquid in the third preheating tank is ν3, and the outflow rate of mixed solution in the continuous mixing tank is ν4, where ν1:ν2 = 2.4:1 to 3.4:1, ν3:ν1 = 45:1 to 55:1, and ν4 = ν1 + ν2 + ν3.

[0019] In some embodiments, the initial heating of the second titanium mixture includes: the mixture being held in the first pipe heater for 60 minutes, and the mixture reaching boiling point after 30 minutes;

[0020] The mixture remains between the first pipe heater and the second pipe heater for 30–40 minutes.

[0021] The secondary heating and dilution process in the second pipe heater includes: staying in the second pipe heater for 3.5 to 4 hours, and then bringing the mixture to a boil again at 20 minutes and maintaining the boiling state.

[0022] In some embodiments, the second pipe heater is connected to a demineralized water pipe, and the water flow rate in the demineralized water pipe is ν5 = (0.2~0.3)ν3.

[0023] In some embodiments, the concentration of TiO2 in the concentrated titanium liquid in the concentrated titanium liquid storage tank is 190-200 g / L, the mass ratio of Fe to TiO2 is 0.28-0.35, and the F value is 1.8-2.0.

[0024] The present invention has at least the following beneficial technical effects:

[0025] The technical problem solved by this invention is to provide a continuous hydrolysis system for titanium dioxide produced by the sulfuric acid process and a method for applying the system. This system and method can transform the intermittent titanium liquid hydrolysis process into continuous production, which can significantly improve production efficiency, reduce the labor intensity of operation, and promote the fully automated production of titanium dioxide produced by the sulfuric acid process. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of an embodiment of the sulfuric acid process titanium dioxide continuous hydrolysis system provided by the present invention;

[0028] Figure 2 This is a schematic diagram of an embodiment of the sulfuric acid process for continuous hydrolysis of titanium dioxide provided by the present invention.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. First preheating tank; 2. Second preheating tank; 3. Third preheating tank; 4. Hydrolysis seed crystal preparation tank; 5. Continuous mixing tank; 6. Temperature control pipeline; 7. Concentrated titanium liquid storage tank; 8. First pipeline heater; 9. Second pipeline heater; 10. Pipeline cooler; 11. Metatitanic acid storage tank; 12. Steam pipeline; 13. Demineralized water pipeline; 14. Pressure pump. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. For example, terms such as “length,” “width,” “upper,” “lower,” “left,” “right,” “front,” “rear,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer” indicate orientations or positions based on the orientations or positions shown in the accompanying drawings and are for ease of description only, and should not be construed as limiting the technical solution.

[0033] The terms "comprising" and "having," and any variations thereof, used in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion; the terms "first," "second," etc., used in the specification, claims, and accompanying drawings are used to distinguish different objects, not to describe a particular order. "A plurality of" means two or more, unless otherwise explicitly specified.

[0034] In the description and claims of this invention and the foregoing drawings, when an element is referred to as "fixed to," "mounted to," "disposed on," or "connected to" another element, it can be located directly or indirectly on that other element. For example, when an element is referred to as "connected to" another element, it can be directly or indirectly connected to that other element.

[0035] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0036] like Figure 1The diagram shown is a schematic representation of an embodiment of the sulfuric acid process titanium dioxide continuous hydrolysis system provided by the present invention. The system includes hydrolysis devices (1, 2, 3, 4, 5), a temperature control pipe 6, a metatitanic acid storage tank 11, and a steam pipe 12.

[0037] The hydrolysis apparatus (1, 2, 3, 4, 5) includes a first preheating tank 1, a second preheating tank 2, a third preheating tank 3, a hydrolysis seed preparation tank 4, and a continuous mixing tank 5. The bottoms of the first preheating tank 1 and the second preheating tank 2 are respectively connected to the top of the hydrolysis seed preparation tank 4 through pipes, and the bottoms of the third preheating tank 3 and the hydrolysis seed preparation tank 4 are respectively connected to the top of the continuous mixing tank 5 through pipes.

[0038] A pipe heater (8, 9) and a pipe cooler (10) are connected sequentially between the first and second ports of the temperature control pipe 6. The first port is connected to the continuous mixing tank 5, and the metatitanic acid storage tank 11 is connected to the second port.

[0039] Each tank of the hydrolysis apparatus (1, 2, 3, 4, 5) is connected to a steam pipe 12 for heating by steam.

[0040] Furthermore, the first preheating tank 1 is a seed titanium liquid preheating tank, the second preheating tank 2 is a dilute alkali liquid preheating tank, and the third preheating tank 3 is a titanium liquid preheating tank.

[0041] Furthermore, the system also includes a concentrated titanium liquid storage tank 7, which is connected to the first preheating tank 1 and the third preheating tank 3 respectively, and continuously supplies concentrated titanium liquid through a pressure pump 14, as described in the title. Figure 1 The pressure pump 14 shown is installed on the pipeline connecting the concentrated titanium liquid storage tank 7 with the first preheating tank 1 and the third preheating tank 3. Multiple flow valves are also installed on this pipeline to control the delivery speed of the concentrated titanium liquid. Each pipeline of the system of the present invention can be equipped with a flow valve and a flow meter to facilitate observation and control of the liquid delivery. Therefore, the flow valve issue of other pipelines will not be described in detail later.

[0042] Furthermore, a first pipe heater 8, a second pipe heater 9, and a pipe cooler 10 are sequentially arranged on the temperature control pipe 6. The second pipe heater 9 is further connected to the demineralized water pipe 13, which is used to dilute the internal liquid by introducing water into the second pipe heater. In some embodiments, the pipe size and length ensure the feed flow rate, allowing the liquid to remain in the first pipe heater for up to 60 minutes and reach boiling point in 30 minutes. A pipe is connected to the rear end of the first pipe heater, with the pipe length designed according to the feed rate, and the titanium liquid is designed to remain in the pipe for 30-40 minutes. The rear end of the pipe is connected to the second pipe heater, with the heater size designed to allow the titanium liquid to remain in the heater for 3.5-4 hours. A demineralized water pipe is connected at 3 / 4 of the length of the second pipe heater for dilution.

[0043] Furthermore, the pipe cooler 10 is a graphite cooler.

[0044] This invention also provides a continuous hydrolysis method for titanium dioxide using the sulfuric acid process, such as... Figure 2 The flowchart shown is for this method, which is implemented using the aforementioned sulfuric acid process for continuous hydrolysis of titanium dioxide. The method includes the following steps:

[0045] Add alkaline solution to the second preheating tank;

[0046] Concentrated titanium liquid is continuously pumped into the first and third preheating tanks through a concentrated titanium liquid storage tank. The concentrated titanium liquid in the first preheating tank and the alkaline solution in the second preheating tank flow into the hydrolysis seed preparation tank to prepare the hydrolysis seed solution. The concentrated titanium liquid in the third preheating tank and the hydrolysis seed solution in the hydrolysis seed preparation tank flow into the continuous mixing tank for continuous mixing to prepare a mixed solution. This mixture is a mixture of hydrolysis titanium liquid and hydrolysis seed solution. The temperature in each tank is controlled by a steam pipeline.

[0047] The mixture flows continuously from the continuous mixing tank into the temperature-controlled pipeline, where it is initially heated in the first pipeline heater, then heated and diluted in the second pipeline heater, and finally cooled to the target temperature by the cooler before being stored in the metatitanic acid storage tank.

[0048] Furthermore, the temperature in the first preheating tank and the second preheating tank is controlled at 96°C through steam pipelines, the temperature in the second preheating tank is controlled at 80-90°C, and the temperature in the hydrolysis seed crystal preparation tank is controlled at 95-98°C through steam pipelines.

[0049] Furthermore, the outflow rate of concentrated titanium liquid in the first preheating tank is ν1, the outflow rate of alkaline solution in the second preheating tank is ν2, the outflow rate of concentrated titanium liquid in the third preheating tank is ν3, and the outflow rate of metatitanic acid in the continuous mixing tank is ν4, ν1:ν2=2.4:1~3.4:1, ν3:ν1=45:1~55:1, and ν4=ν1+ν2+ν3.

[0050] Furthermore, the initial heating of the mixture includes: the mixture staying in the first pipe heater for 60 minutes, and the mixture reaching boiling point after 30 minutes;

[0051] The mixture remains between the first pipe heater and the second pipe heater for 30–40 minutes.

[0052] The secondary heating and dilution process in the second pipe heater includes: staying in the second pipe heater for 3.5 to 4 hours, and then bringing the mixture to a boil again at 20 minutes and maintaining the boiling state.

[0053] Furthermore, the second pipeline heater is connected to a demineralized water pipeline, and the water flow rate in the demineralized water pipeline is ν5 = (0.2~0.3)ν3.

[0054] Furthermore, the concentration of TiO2 in the concentrated titanium liquid in the concentrated titanium liquid storage tank is 190-200 g / L, the mass ratio of Fe to TiO2 is 0.28-0.35, and the F value is 1.8-2.0. This F value is the effective acid ratio, that is, the ratio of the total amount of acid bound to titanium and free acid to the amount of TiO2.

[0055] Furthermore, the alkaline solution in the second preheating tank is an 8%–10% NaOH solution, which is indirectly heated to 80–90°C using steam through a coil.

[0056] Furthermore, after the liquid is processed in the heater pipe, the resulting metatitanic acid is cooled to below 80°C by a graphite cooler and then stored in a metatitanic acid storage tank.

[0057] The present invention will be further explained below with reference to specific embodiments. In the specific embodiments, the first preheating tank is a seed titanium liquid preheating tank, the second preheating tank is a dilute alkali solution preheating tank, and the third preheating tank is a titanium liquid preheating tank. Embodiment 1 is a case where the titanium liquid concentration, iron-titanium ratio and F value are relatively low. Embodiment 2 is a case where the titanium liquid concentration, iron-titanium ratio and F value are relatively high. Embodiment 3 is a case where the titanium liquid concentration, iron-titanium ratio and F value are moderate.

[0058] Example 1

[0059] The hydrolysis apparatus includes a seed titanium liquid preheating tank, a titanium liquid preheating tank, a dilute alkali solution preheating tank, a hydrolysis seed preparation tank, and a continuous mixing tank. The titanium liquid concentration (TiO2) in the seed titanium liquid preheating tank and the titanium liquid preheating tank is 190 g / L, the iron-titanium ratio (Fe / TiO2 mass ratio) is 0.28, and the F value is 1.8. Both are indirectly heated to 96°C by steam through a coil. The 10% NaOH solution in the dilute alkali solution preheating tank is indirectly heated to 85°C by steam through a coil.

[0060] The discharge flow rate of the titanium liquid in the seed titanium liquid preheating tank is set to 0.18 m / s. 3 / h (180L / h), calculated according to ν1:ν2 = 3.4:1, the dilute alkali solution discharge flow rate is 0.053m³. 3 / h (53L / h), use steam to indirectly heat the mixed solution to 95℃~98℃;

[0061] A continuous mixing tank is added after the titanium liquid preheating tank and the seed crystal preparation tank for continuous mixing of the preheated titanium liquid and the hydrolyzed seed crystals. Based on the ratio of the discharge flow rate of the titanium liquid preheating tank to the discharge flow rate of the seed titanium liquid being ν3:ν1 = 55:1, the discharge flow rate of the titanium liquid preheating tank is set to 10 m³ / s. 3 / h.

[0062] A flow meter is installed at the bottom discharge port of the continuous mixer, and its flow rate ν4 = ν1 + ν2 + ν3 = 10.233 m³ / s. 3 / h. A first pipeline heater is installed downstream of the flow meter, and the pipeline volume is 11m³. 3 With an inner diameter of 1.53m and a length of 6m, this size of pipe heater can meet the requirement that the titanium liquid stays in the heater for up to 60 minutes. The heating steam flow rate is adjusted so that the temperature from the middle position of the heater to the outlet reaches 103-106℃ (boiling).

[0063] The first pipeline heater is connected to a naturally cooled annular pipeline at its rear end. The pipeline is designed to allow the titanium liquid to remain in the pipeline for 30 minutes. The pipeline has an inner diameter of 1.53m and a length of 3m.

[0064] The natural cooling pipe is connected to a second pipe heater at the rear end. The heater is designed to accommodate a 4-hour residence time of the molten titanium in the heater, with an inner diameter of 1.53m and a length of 24m. The steam flow rate is adjusted so that the molten titanium in the second pipe (2m from the heater outlet) is heated to 105-110℃ and boiled again within 20 minutes.

[0065] A dilution water pipe is connected at the 18m (3 / 4 position) mark of the second pipe heater length. The dilution water flow rate is calculated as ν5 = 0.2 * ν3, which is 2m. 3 / h.

[0066] The second pipeline heater is connected to a graphite cooler and a metatitanic acid storage tank. After the reaction is completed, the metatitanic acid is cooled to below 80°C by the graphite cooler and then stored in the metatitanic acid storage tank.

[0067] Example 2

[0068] The hydrolysis apparatus includes a seed titanium liquid preheating tank, a titanium liquid preheating tank, a dilute alkali solution preheating tank, a hydrolysis seed preparation tank, and a continuous mixing tank. The titanium liquid concentration (based on TiO2) in the seed titanium liquid preheating tank and the titanium liquid preheating tank is 200 g / L, the iron-titanium ratio (Fe / TiO2 mass ratio) is 0.35, and the F value is 2.0. Both are indirectly heated to 96°C by steam through a coil. The 8% NaOH solution in the dilute alkali solution preheating tank is indirectly heated to 85°C by steam through a coil.

[0069] The discharge flow rate of the titanium liquid in the seed titanium liquid preheating tank is set to 0.222 m / s. 3 / h (220L / h), calculated according to ν1:ν2=2.4:1, the dilute alkali solution discharge flow rate is 0.093m. 3 / h (92L / h), use steam to indirectly heat the mixed solution to 95℃~98℃;

[0070] A continuous mixing tank is added after the titanium liquid preheating tank and the seed crystal preparation tank for continuous mixing of the preheated titanium liquid and the hydrolyzed seed crystals. Based on the ratio of the discharge flow rate of the titanium liquid preheating tank to the discharge flow rate of the seed titanium liquid being ν3:ν1 = 45:1, the discharge flow rate of the titanium liquid preheating tank is set to 10 m³ / s. 3 / h.

[0071] A flow meter is installed at the bottom discharge port of the continuous mixer, and its flow rate ν4 = ν1 + ν2 + ν3 = 10.315 m³ / s. 3 / h. A first pipeline heater is installed downstream of the flow meter, and the pipeline volume is 11m³. 3 With an inner diameter of 1.53m and a length of 6m, this size of pipe heater can meet the requirement that the titanium liquid stays in the heater for up to 60 minutes. The heating steam flow rate is adjusted so that the temperature from the middle position of the heater to the outlet reaches 103-106℃ (boiling).

[0072] The first pipeline heater is connected to a naturally cooled annular pipeline at its rear end. The pipeline is designed to allow the titanium liquid to remain in the pipeline for 30 minutes. The pipeline has an inner diameter of 1.53m and a length of 3m.

[0073] The natural cooling pipe is connected to a second pipe heater at the rear end. The heater is designed to accommodate a 4-hour residence time of the molten titanium in the heater, with an inner diameter of 1.53m and a length of 24m. The steam flow rate is adjusted so that the molten titanium in the second pipe (2m from the heater outlet) is heated to 105-110℃ and boiled again within 20 minutes.

[0074] A dilution water pipe is connected at the 18m (3 / 4 position) mark of the second pipe heater length. The dilution water flow rate is calculated as ν5 = 0.3 * ν3, which is 3m. 3 / h.

[0075] The second pipeline heater is connected to a graphite cooler and a metatitanic acid storage tank. After the reaction is completed, the metatitanic acid is cooled to below 80°C by the graphite cooler and then stored in the metatitanic acid storage tank.

[0076] Example 3

[0077] The hydrolysis apparatus includes a seed titanium liquid preheating tank, a titanium liquid preheating tank, a dilute alkali solution preheating tank, a hydrolysis seed preparation tank, and a continuous mixing tank. The titanium liquid concentration (based on TiO2) in the seed titanium liquid preheating tank and the titanium liquid preheating tank is 195 g / L, the iron-titanium ratio (Fe / TiO2 mass ratio) is 0.30, and the F value is 1.9. Both are indirectly heated to 96-98°C by steam through coils. The 9% NaOH solution in the dilute alkali solution preheating tank is indirectly heated to 85°C by steam through coils.

[0078] The discharge flow rate of the titanium liquid in the seed titanium liquid preheating tank is set to 0.2m. 3 / h (220L / h), calculated according to ν1:ν2=3:1, the dilute alkali solution discharge flow rate is 0.067m. 3 / h (67L / h), the mixed solution is indirectly heated to 95℃~98℃ using steam;

[0079] A continuous mixing tank is added after the titanium liquid preheating tank and the seed crystal preparation tank for continuous mixing of the preheated titanium liquid and the hydrolyzed seed crystals. Based on a ratio of ν3:ν1 = 50:1 for the discharge flow rate of the titanium liquid preheating tank to the discharge flow rate of the seed titanium liquid, the discharge flow rate of the titanium liquid preheating tank is set to 10 m³ / s. 3 / h.

[0080] A flow meter is installed at the bottom discharge port of the continuous mixer, and its flow rate ν4 = ν1 + ν2 + ν3 = 10.267 m³ / s. 3 / h. A first pipeline heater is installed downstream of the flow meter, and the pipeline volume is 11m³. 3 With an inner diameter of 1.53m and a length of 6m, this size of pipe heater can meet the requirement that the titanium liquid stays in the heater for up to 60 minutes. The heating steam flow rate is adjusted so that the temperature from the middle position of the heater to the outlet reaches 103-106℃ (boiling).

[0081] The first pipeline heater is connected to a naturally cooled annular pipeline at its rear end. The pipeline is designed to allow the titanium liquid to remain in the pipeline for 30 minutes. The pipeline has an inner diameter of 1.53m and a length of 3m.

[0082] The natural cooling pipe is connected to a second pipe heater at the rear end. The heater is designed to accommodate a 4-hour residence time of the molten titanium in the heater, with an inner diameter of 1.53m and a length of 24m. The steam flow rate is adjusted so that the molten titanium in the second pipe (2m from the heater outlet) is heated to 105-110℃ and boiled again within 20 minutes.

[0083] A dilution water pipe is connected at 18m (3 / 4 position) of the length of the second pipe heater. The dilution water flow rate is calculated to be 2.5m based on ν5 = 0.25 * ν3. 3 / h.

[0084] The second pipeline heater is connected to a graphite cooler and a metatitanic acid storage tank. After the reaction is completed, the metatitanic acid is cooled to below 80°C by the graphite cooler and then stored in the metatitanic acid storage tank.

[0085] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0086] It should be understood that, as used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, “and / or” refers to any and all possible combinations of one or more of the associated listed items.

[0087] The embodiment numbers disclosed in the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0088] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A continuous hydrolysis system for titanium dioxide produced via sulfuric acid process, characterized in that, include: The hydrolysis unit, temperature control pipeline, metatitanic acid storage tank, and steam pipeline are included. The hydrolysis device includes a first preheating tank, a second preheating tank, a third preheating tank, a hydrolysis seed preparation tank, and a continuous mixing tank. The bottoms of the first preheating tank and the second preheating tank are respectively connected to the top of the hydrolysis seed preparation tank through pipes, and the bottoms of the third preheating tank and the hydrolysis seed preparation tank are respectively connected to the top of the continuous mixing tank through pipes. A pipe heater and a pipe cooler are connected sequentially between the first and second ports of the temperature control pipe. The first port is connected to the continuous mixing tank, and the metatitanic acid storage tank is connected to the second port. Each tank of the hydrolysis device is connected to the steam pipe for heating by steam.

2. The continuous hydrolysis system for titanium dioxide produced by sulfuric acid process according to claim 1, characterized in that, It also includes a concentrated titanium liquid storage tank, which is connected to the first preheating tank and the third preheating tank through pipelines and continuously delivers concentrated titanium liquid through a pressure pump.

3. The continuous hydrolysis system for titanium dioxide produced by sulfuric acid process according to claim 2, characterized in that, The temperature control pipeline is sequentially equipped with a first pipeline heater, a second pipeline heater, and a pipeline cooler, and the second pipeline heater is further connected to the demineralized water pipeline.

4. The continuous hydrolysis system for titanium dioxide produced by sulfuric acid process according to claim 3, characterized in that, The pipe cooler is a graphite cooler.

5. A continuous hydrolysis method for titanium dioxide using the sulfuric acid process, wherein the method is implemented by the system described in any one of claims 1 to 4, characterized in that, include: Add alkaline solution to the second preheating tank; Concentrated titanium liquid is continuously pumped into the first preheating tank and the third preheating tank through a concentrated titanium liquid storage tank. The concentrated titanium liquid in the first preheating tank and the alkaline solution in the second preheating tank flow into a hydrolysis seed preparation tank to prepare a hydrolysis seed solution. The concentrated titanium liquid in the third preheating tank and the hydrolysis seed solution in the hydrolysis seed preparation tank flow into a continuous mixing tank for continuous mixing to prepare a mixed solution. The temperature in each tank is controlled by a steam pipe. The mixture flows continuously from the continuous mixing tank into the temperature-controlled pipeline, where it is initially heated in the first pipeline heater, then heated and diluted in the second pipeline heater, and finally cooled to the target temperature by a cooler before being stored in the metatitanic acid storage tank.

6. The continuous hydrolysis method for titanium dioxide using the sulfuric acid process according to claim 5, characterized in that, The temperature in the first preheating tank and the second preheating tank is controlled at 96°C through a steam pipe, the temperature in the second preheating tank is controlled at 80~90°C, and the temperature in the hydrolysis seed crystal preparation tank is controlled at 95~98°C through a steam pipe.

7. The continuous hydrolysis method for titanium dioxide using the sulfuric acid process according to claim 5, characterized in that, The outflow rate of concentrated titanium liquid in the first preheating tank is ν1, the outflow rate of alkaline solution in the second preheating tank is ν2, the outflow rate of concentrated titanium liquid in the third preheating tank is ν3, and the outflow rate of mixed liquid in the continuous mixing tank is ν4. ν1:ν2=2.4:1~3.4:1, ν3:ν1=45:1~55:1, and ν4=ν1+ν2+ν3.

8. The continuous hydrolysis method for titanium dioxide using the sulfuric acid process according to claim 5, characterized in that, The preliminary heating of the mixture includes: the mixture staying in the first pipeline heater for 60 minutes, and the mixture reaching boiling point after 30 minutes; The mixture remains between the first pipe heater and the second pipe heater for 30-40 minutes; The secondary heating and dilution in the second pipe heater includes: staying in the second pipe heater for 3.5 to 4 hours, and the mixture reaching boiling again after 20 minutes and maintaining boiling.

9. The continuous hydrolysis method for titanium dioxide using the sulfuric acid process according to claim 8, characterized in that, The second pipe heater is connected to a demineralized water pipe, and the water flow rate in the demineralized water pipe is ν5 = (0.2~0.3)ν3.

10. The continuous hydrolysis method for titanium dioxide using the sulfuric acid process according to claim 5, characterized in that, The concentration of TiO2 in the concentrated titanium liquid in the concentrated titanium liquid storage tank is 190~200g / l, the mass ratio of Fe to TiO2 is 0.28~0.35, and the F value is 1.8~2.0.

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