Titanium dioxide continuous coating system

Abstract

The utility model discloses a continuous coating system for titanium dioxide. The continuous coating system comprises a plurality of coating tanks which are connected in sequence, the coating tank comprises an outer tank and an inner tank located in the outer tank, and a first stirring device is arranged in the inner tank; a coating agent inlet, a first titanium dioxide slurry inlet and a first pH regulator inlet are formed in the upper part of the inner tank and are respectively used for adding a coating agent, titanium dioxide slurry and a pH regulator, and a circulating opening communicated with the outer tank is formed in the lower part of the inner tank; a first overflow port is formed in the upper part of the outer tank and is used for discharging titanium dioxide slurry which is coated in the coating tank. According to the titanium dioxide continuous coating system, continuous coating of titanium dioxide is achieved, and the production efficiency is improved. And the double-layer coating tank is arranged, so that the flowing path and the retention time of the slurry are prolonged, the coating reaction is more sufficient, and the coating is more uniform.

Description

Technical Field

[0001] The utility model belongs to the technical field of titanium dioxide production, and particularly relates to a titanium dioxide continuous coating system. Background Art

[0002] In order to improve the performance of titanium dioxide, titanium dioxide generally needs to be coated with single or multiple inorganic coatings such as silicon, aluminum, zirconium, and phosphorus. The traditional coating method is single-batch intermittent coating. Taking the zirconium-aluminum two-component coating as an example, the sand-milled slurry is first put into the coating tank. After adjusting the concentration, pH, and temperature, sodium hexametaphosphate is added for homogenization. Then, zirconium dichloride, aluminum sulfate, and sodium metaaluminate are added in sequence. Before and after the addition of the coating agent, the pH, temperature, and homogenization steps are also included. The coating end point also includes the step of adjusting the end point pH. After the entire coating is completed, the slurry is fed into the next process and re-filled for the next coating. The entire coating process takes more than 8 hours. When more multiple coatings are used, it will take longer and the production efficiency will be low. Utility Model Content

[0003] The purpose of the utility model is to provide a titanium dioxide continuous coating system to solve the deficiencies of the prior art.

[0004] The purpose of this utility model is achieved by the following technical solutions:

[0005] A titanium dioxide continuous coating system comprises a plurality of coating tanks connected in sequence;

[0006] The coating tank is used to add a coating agent to the titanium dioxide slurry for coating; the coating tank includes an outer tank and an inner tank located inside the outer tank, and a first stirring device is provided in the inner tank; the inner tank is provided with a coating agent inlet, a first titanium dioxide slurry inlet, and a first pH regulator inlet at the top, which are respectively used to add the coating agent, titanium dioxide slurry and pH regulator, and the inner tank is provided with a flow port connected to the outer tank at the bottom; the outer tank is provided with a first overflow port at the top, which is used to discharge the titanium dioxide slurry that has been coated in the coating tank.

[0007] Preferably, the titanium dioxide continuous coating system provided in the present application further includes a slurry mixing tank and a pH adjustment tank respectively located before and after the coating tank.

[0008] Preferably, the titanium dioxide continuous coating system provided in the present application further includes a temperature regulation system for regulating the slurry mixing tank and the coating tank to be at a target temperature.

[0009] Preferably, the temperature regulating system includes a hot steam delivery main pipe, a plurality of steam delivery branches respectively connected to the slurry mixing tank and the coating tank, and a plurality of temperature detection sensors;

[0010] The plurality of temperature detection sensors are used to detect the temperature of the titanium dioxide slurry from the slurry mixing tank and the coating tank respectively;

[0011] Each of the steam delivery branches is provided with a control valve for adjusting the hot steam delivery amount, thereby adjusting the temperature of the corresponding slurry mixing tank and the coating tank.

[0012] Preferably, the end of the steam delivery branch pipe connected to the coating tank is directly connected to the outer tank.

[0013] Preferably, a second stirring device is provided in the slurry mixing tank;

[0014] The slurry mixing tank is provided with a second titanium dioxide slurry inlet, a second pH regulator inlet, a desalted water inlet and a discharge port.

[0015] Preferably, the pH adjusting tank also includes an outer tank and an inner tank located inside the outer tank, and a third stirring device is provided in the inner tank of the pH adjusting tank; a third titanium dioxide slurry inlet and a third pH adjusting agent inlet are provided at the top of the inner tank of the pH adjusting tank; and a second overflow port is provided at the top of the outer tank of the pH adjusting tank.

[0016] Preferably, the titanium dioxide continuous coating system provided in the present application further includes a plurality of pH detection sensors, which are respectively used to detect the pH of the titanium dioxide slurry from the slurry mixing tank, the coating tank and the pH adjustment tank.

[0017] Preferably, the titanium dioxide continuous coating system provided in the present application further includes a post-coating tank connected to the pH adjustment tank, which is used to store the titanium dioxide slurry after coating and pH adjustment.

[0018] Preferably, a fourth stirring device is provided in the coating tank.

[0019] The titanium dioxide continuous coating system provided in this application achieves continuous coating of titanium dioxide, improving production efficiency. Furthermore, by providing a double-layer coating tank, the slurry flow path and residence time are extended, resulting in a more complete coating reaction and a more uniform coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of the titanium dioxide continuous coating system provided by the present application;

[0021] Among them, 1-slurry mixing tank; 11-second stirring device; 12-second titanium dioxide slurry delivery pipeline; 13-second pH regulator delivery pipeline; 14-desalted water delivery pipeline; 15-discharge port; 2-coating tank; 21-first stirring device; 22-coating agent delivery pipeline; 23-first titanium dioxide slurry delivery pipeline; 24-first pH regulator delivery pipeline; 25-circulation port; 26-first overflow port; 3-pH adjusting tank; 31-third stirring device; 32-third titanium dioxide slurry delivery pipeline; 33-third pH regulator delivery pipeline; 34-second overflow port; 4-post-coating tank; 41-fourth stirring device; 42-post-coating slurry delivery pipeline; 51-steam delivery main pipe; 52-steam delivery branch pipe; 53-temperature detection sensor; 54-control valve; 6-pH detection sensor; 7-delivery pump. DETAILED DESCRIPTION

[0022] The titanium dioxide continuous coating system provided by this application is as follows: Figure 1 As shown, it includes several coating tanks 2 connected in sequence.

[0023] Titanium dioxide slurry for coating, especially sulfuric acid-processed titanium dioxide slurry, generally requires sand milling to ensure that the titanium dioxide particle size meets the coating requirements. The titanium dioxide slurry obtained by sand milling has a higher concentration, while the titanium dioxide slurry required for coating is lower, generally between 250 and 400 g / L. Furthermore, downstream customers have different requirements for the pH of titanium dioxide powder, and to facilitate water washing, the pH of titanium dioxide powder generally needs to be adjusted to an appropriate range after coating. Therefore, preferably, a slurry mixing tank 1 is provided before the coating tank, and a pH adjustment tank 3 is provided after the coating tank 2, along the flow direction of the titanium dioxide slurry.

[0024] Further preferably, a second stirring device 11 is provided in the slurry mixing tank 1; a second titanium dioxide slurry inlet, a second pH adjusting agent inlet, a desalted water inlet, and a discharge port 15 are provided on the slurry mixing tank 1. The second titanium dioxide slurry inlet is connected to a second titanium dioxide slurry delivery pipeline 12 for delivering the sand-milled titanium dioxide slurry; the desalted water inlet is connected to a desalted water delivery pipeline 14 for delivering desalted water to adjust the concentration of the titanium dioxide slurry; the second pH adjusting agent inlet is connected to a second pH adjusting agent delivery pipeline 13 for delivering a second pH adjusting agent for adjusting the pH of the titanium dioxide slurry; and the discharge port 15 is used to discharge the slurry after slurry mixing.

[0025] The uncoated titanium dioxide slurry that has passed the sand milling is first transported to the slurry mixing tank through the second titanium dioxide slurry delivery pipeline 12 and the second titanium dioxide slurry inlet, and desalted water at an appropriate flow rate is delivered to the slurry mixing tank 1 through the desalted water delivery pipeline 14 and the desalted water inlet. The materials are fully mixed under the action of the second stirring device 11 to obtain a titanium dioxide slurry that meets the target slurry concentration, and then discharged to the coating tank 2 through the discharge port 15. When the pH of the slurry needs to be adjusted, the pH adjuster at an appropriate flow rate is simultaneously delivered to the slurry mixing tank 1 through the second pH adjuster delivery pipeline 13 and the second pH adjuster inlet to adjust the pH of the slurry to the target range.

[0026] The slurry can also be prepared in advance by prefabrication method. A batch of slurry that meets the standard requirements is prepared in advance, and then it is continuously transported to the coating tank at an appropriate flow rate during coating production.

[0027] Coating tank 2 is used to add coating agent to titanium dioxide slurry for coating; the number of coating tanks is adjusted according to the type of coating agent, such as Figure 1 As shown, it includes two coating tanks, that is, there are two corresponding coating agents. This application adopts an inner and outer double-layer tank body, specifically including an outer tank and an inner tank located within the outer tank. The inner tank is equipped with a first stirring device 21; the inner tank is provided with a coating agent inlet, a first titanium dioxide slurry inlet, and a first pH adjuster inlet at the top. The coating agent inlet is connected to a coating agent delivery pipeline 22, the first titanium dioxide slurry inlet is connected to a first titanium dioxide slurry delivery pipeline 23, the other end of the first titanium dioxide slurry delivery pipeline 23 is connected to the slurry mixing tank or the previous coating tank, and the first pH adjuster inlet is connected to a first pH adjuster delivery pipeline 24, which are used to add the coating agent, the titanium dioxide slurry from the slurry mixing tank or the previous coating tank, and the pH adjuster, respectively. The inner tank is provided with a flow port 25 at the bottom that connects to the outer tank; the outer tank is provided with a first overflow port 26 at the top for discharging the coated titanium dioxide slurry in the coating tank. The flow rates of the coating agent and pH adjuster are adjusted according to the coating amount and the coating pH.

[0028] In traditional single-batch coating, after the material is completely added to the coating tank and the reaction is completed, the material is discharged. However, this application adopts a continuous coating method. In different tanks, the slurry is continuously added and discharged. The slurry is in a continuous flow process during the entire coating process. Therefore, the material in the tank can easily be discharged from the tank when the mixing is uneven and the reaction is insufficient, especially in the coating tank.

[0029] To address the above issues, the present application sets up a double-layer coating tank. The coating agent, titanium dioxide slurry, and pH adjuster first enter the inner tank from the top, then flow from top to bottom in the inner tank. During the flow process, they are fully mixed and reacted under the action of the stirring device. They then flow into the outer tank through the flow port and are discharged from bottom to top through the first overflow port to the next coating tank or pH adjustment tank. The material flow direction is shown by the arrow. Compared with a single-layer tank, the inner and outer coating tanks extend the slurry flow path and residence time, making the coating reaction more complete and the coating more uniform, which effectively solves the above technical problems.

[0030] Preferably, in order to make the slurry mixing uniform, the slurry mixing tank also adopts a double-layer tank body like the coating tank. The second titanium dioxide slurry inlet, the second pH regulator inlet, and the desalted water inlet are located at the top of the inner tank body, and the discharge port 15 is located above the outer tank body.

[0031] Preferably, the pH adjustment tank 3, like the coating tank, employs a double-layered tank body, with a third stirring device 31 located within the inner tank. A third titanium dioxide slurry inlet and a third pH adjuster inlet are located near the top of the inner tank, while a second overflow port 34 is located near the top of the outer tank. The third titanium dioxide slurry inlet is connected to a third titanium dioxide slurry delivery pipeline 32, the other end of which is connected to the final coating tank. The third pH adjuster inlet is connected to a third pH adjuster delivery pipeline 33. After coating, the slurry flows into the pH adjustment tank, where it is thoroughly mixed with the third pH adjuster by the stirring device, resulting in a slurry with a pH that meets the target requirement. The slurry is then discharged through the second overflow port 34.

[0032] By setting up a slurry mixing tank and a pH adjustment tank, slurry mixing, film coating and terminal pH adjustment can be carried out in different tanks, further improving production efficiency.

[0033] Preferably, the present application further comprises a plurality of pH adjusting agent storage tanks and coating agent storage tanks for storing the corresponding materials. The pH adjusting agent delivery pipeline and the coating agent delivery pipeline are also provided with control valves for controlling the material delivery flow.

[0034] Preferably, a post-coating tank 4 is provided behind the pH adjustment tank 3 for storing the titanium dioxide slurry after coating and pH adjustment. A fourth stirring device 41 is provided in the post-coating tank 4 to continuously stir the titanium dioxide slurry, keeping it in a uniformly dispersed state and preventing slurry agglomeration. When the slurry in the post-coating tank reaches a certain volume, it is transported to the next process, namely the filter press, for filtration through the post-coating slurry delivery pipeline 42. Preferably, in order to facilitate the delivery of the titanium dioxide slurry, a delivery pump 7 may be provided on the post-coating slurry delivery pipeline 42.

[0035] Preferably, the present application also includes several pH detection sensors 6, which are used to detect the pH of the titanium dioxide slurry from the slurry mixing tank, the coating tank and the pH adjustment tank respectively. The pH detection sensor 6 is preferably interlocked with the control valve of the pH adjuster delivery pipeline. When the detected pH does not meet the target requirements, it can be fed back to the control valve to timely adjust the pH adjuster delivery flow.

[0036] It is generally known to those skilled in the art that titanium dioxide coating requires not only an appropriate pH but also an appropriate temperature. Therefore, the present application is provided with a temperature control system for adjusting the slurry mixing tank 1 and the coating tank 2 to be at the target temperature.

[0037] Furthermore, the temperature regulation system includes a hot steam delivery main pipe 51, several steam delivery branches 52 respectively connected to the slurry mixing tank 1 and the coating tank 2, and several temperature detection sensors 53; several temperature detection sensors are used to detect the temperature of the titanium dioxide slurry from the slurry mixing tank 1 and the coating tank 2 respectively; each steam delivery branch pipe 52 is provided with a control valve 54, which is used to adjust the hot steam delivery amount according to the detection information of the temperature detection sensor, and thereby adjust the temperature of the slurry mixing tank and the coating tank.

[0038] Furthermore, the end of the steam delivery branch pipe connected to the coating tank is directly connected to the outer tank, and hot steam is first delivered to the outer tank. The end of the steam delivery branch pipe is connected to the outer tank, which can leave enough space for the inner tank, expand the area of ​​the stirring device, improve the stirring effect, and thus improve the coating effect.

[0039] The pH detection sensor and the temperature detection sensor are preferably arranged on the titanium dioxide slurry conveying pipeline between the front and rear tanks.

[0040] Therefore, the continuous coating system provided in this application not only realizes the continuous coating of titanium dioxide, greatly improving the production capacity, but also fully guarantees the coating effect and product quality.

[0041] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Clearly, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, to the extent such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to encompass such changes and modifications.

Claims

1. A titanium dioxide continuous coating system, characterized in that: It includes several coating tanks connected in sequence; The coating tank is used to add a coating agent to the titanium dioxide slurry for coating; the coating tank includes an outer tank and an inner tank located inside the outer tank, and a first stirring device is provided in the inner tank; the inner tank is provided with a coating agent inlet, a first titanium dioxide slurry inlet, and a first pH regulator inlet at the top, which are respectively used to add the coating agent, titanium dioxide slurry and pH regulator, and the inner tank is provided with a flow port connected to the outer tank at the bottom; the outer tank is provided with a first overflow port at the top, which is used to discharge the titanium dioxide slurry that has been coated in the coating tank.

2. The titanium dioxide continuous coating system according to claim 1, characterized in that: It also includes a slurry mixing tank and a pH adjustment tank respectively located before and after the coating tank.

3. The titanium dioxide continuous coating system according to claim 2, characterized in that: It also includes a temperature regulating system for regulating the slurry mixing tank and the coating tank to be at a target temperature.

4. The titanium dioxide continuous coating system according to claim 3, characterized in that: The temperature regulating system includes a hot steam delivery main pipe, a plurality of steam delivery branches respectively connected to the slurry mixing tank and the coating tank, and a plurality of temperature detection sensors; The plurality of temperature detection sensors are used to detect the temperature of the titanium dioxide slurry from the slurry mixing tank and the coating tank respectively; Each of the steam delivery branches is provided with a control valve for adjusting the hot steam delivery amount, thereby adjusting the temperature of the corresponding slurry mixing tank and the coating tank.

5. The titanium dioxide continuous coating system according to claim 4, characterized in that: The end of the steam delivery branch pipe communicated with the coating tank is directly communicated with the outer tank.

6. The titanium dioxide continuous coating system according to claim 2, characterized in that: A second stirring device is provided in the slurry mixing tank; The slurry mixing tank is provided with a second titanium dioxide slurry inlet, a second pH regulator inlet, a desalted water inlet and a discharge port.

7. The titanium dioxide continuous coating system according to claim 2, characterized in that: The pH adjusting tank also includes an outer tank and an inner tank located inside the outer tank. A third stirring device is provided in the inner tank of the pH adjusting tank. A third titanium dioxide slurry inlet and a third pH adjusting agent inlet are provided at the top of the inner tank of the pH adjusting tank. A second overflow port is provided at the top of the outer tank of the pH adjusting tank.

8. The titanium dioxide continuous coating system according to claim 2, characterized in that: It also includes several pH detection sensors, which are used to detect the pH of the titanium dioxide slurry from the slurry mixing tank, the coating tank and the pH adjustment tank respectively.

9. The titanium dioxide continuous coating system according to claim 2, characterized in that: It also includes a post-coating tank connected to the pH adjustment tank, which is used to store the titanium dioxide slurry after the coating is completed and the pH is adjusted.

10. The titanium dioxide continuous coating system according to claim 9, characterized in that: A fourth stirring device is provided in the film-coated tank.

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