A device and method for recycling the filtrate after titanium white surface treatment

Abstract

The present invention relates to a device for recycling the filtrate after titanium dioxide surface treatment, comprising: a filtrate storage tank connected to the filtration device after titanium dioxide surface treatment to collect the filtrate after surface treatment; a first pipeline connecting the filtrate storage tank to a beating tank, the beating tank being arranged upstream of the titanium dioxide surface treatment process; a second pipeline connecting the filtrate storage tank to a coating tank, the coating tank being arranged upstream of the titanium dioxide surface treatment process; and a pump connected to the first pipeline and the second pipeline to selectively pump the filtrate after surface treatment to at least one of the beating tank and the coating tank. By introducing the filtrate after titanium dioxide surface treatment into the beating tank and / or the coating tank, the device can further improve the recovery rate of titanium dioxide in the titanium dioxide production process and reduce the pressure of wastewater treatment. The present invention also provides a method for recycling the filtrate after titanium dioxide surface treatment using this device.

Description

Technical Field

[0001] The present invention relates to the chemical industry field, specifically to the titanium dioxide production field, and more specifically, to a recycling device for the filtrate after titanium dioxide surface treatment and a method for recycling the filtrate after titanium dioxide surface treatment using this device. Background Art

[0002] Titanium dioxide is an important industrial raw material and has a large number of applications in industries such as coatings, plastics, inks, and papermaking. Whiteness is one of the important indicators of titanium dioxide. In order to obtain better whiteness, the impurity content of the product, especially the iron content, must be strictly controlled.

[0003] During the production process of titanium dioxide, multiple filtration and washing processes are involved. In each filtration and washing process, a part of titanium dioxide passes through the filter into the filtrate. The recovery of titanium in the filtrate is related to the overall titanium yield of the process. Inorganic surface treatment is one of the important processes in the sulfuric acid process for titanium dioxide production. After surface treatment, the slurry needs to be filtered and washed. Among them, most of the washing water can be recycled for the second washing, but the filtrate cannot be used for the second washing (filtration and washing after bleaching) because it contains a small amount of inorganic coating agents. Otherwise, the metal particles contained in the coating agents will affect the salt treatment effect. Currently, the filtrate after the third washing (i.e., the filtrate after surface treatment) mainly enters the wastewater treatment system after sedimentation and filtration, which will inevitably result in the loss of part of titanium dioxide and also increase the burden on the wastewater treatment system. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the main purpose of the present invention is to provide a recycling device for the filtrate after titanium dioxide surface treatment. By introducing the filtrate after titanium dioxide surface treatment into the beating tank and / or the coating tank, the recycling of the filtrate after titanium dioxide surface treatment is realized, further improving the recovery rate of titanium dioxide in the titanium dioxide production process and reducing the pressure of wastewater treatment. The present invention also provides a method for recycling the filtrate after titanium dioxide surface treatment using this device.

[0005] According to the present invention, there is provided a recycling device for the filtrate after titanium dioxide surface treatment, comprising:

[0006] A filtrate storage tank, which is connected to the filtration device after titanium dioxide surface treatment to collect the filtrate after surface treatment;

[0007] A first pipeline, which connects the filtrate storage tank to the beating tank, and the beating tank is arranged upstream of the titanium dioxide surface treatment process;

[0008] A second pipeline, which connects the filtrate storage tank to the coating tank, and the coating tank is arranged upstream of the titanium dioxide surface treatment process; and

[0009] A pump, which is connected to the first pipeline and the second pipeline to selectively pump the filtrate after surface treatment to at least one of the beating tank and the coating tank.

[0010] According to the present invention, there is provided a method for recycling the filtrate after titanium white surface treatment, comprising the following steps:

[0011] 1) Collect the filtrate after titanium white surface treatment into a filtrate storage tank;

[0012] 2) The filtrate after titanium white surface treatment in the filtrate storage tank is pumped through a first pipeline to a beating tank, and is mixed and beaten with titanium dioxide powder after roll pressing to obtain a slurry.

[0013] According to an embodiment of the present invention, in step 2), the beating concentration of the filtrate after titanium white surface treatment and titanium dioxide powder is 400 - 1000 g / l.

[0014] According to an embodiment of the present invention, the method further comprises the following steps:

[0015] 3) Wet grind the slurry.

[0016] According to an embodiment of the present invention, in step 3), the wet grinding includes at least one of wet ball milling and sand milling.

[0017] According to an embodiment of the present invention, the method further comprises the following steps:

[0018] 4) Pump the slurry after wet grinding into a coating tank;

[0019] 5) The filtrate after titanium white surface treatment in the filtrate storage tank is pumped through a second pipeline to the coating tank to dilute the slurry after wet grinding, and the coated slurry is obtained through the surface treatment process.

[0020] According to an embodiment of the present invention, in step 5), the slurry after wet grinding is diluted to a concentration of 270 - 320 g / l.

[0021] According to an embodiment of the present invention, the coated slurry is filtered twice through a filtering device to obtain the filtrate after titanium white surface treatment, and steps 1) - 5) are repeated to realize the recycling of the filtrate after titanium white surface treatment.

[0022] By adopting the above technical solution, compared with the prior art, the present invention can further improve the recovery rate of titanium dioxide in the titanium white production process and reduce the pressure of wastewater treatment. Brief Description of the Drawings

[0023] Figure 1 The flow chart of the recycling process of the filtrate after titanium white surface treatment according to the present invention is shown. Detailed Description of the Invention

[0024] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments of the present invention have been described in detail, those skilled in the art can easily appreciate that various modifications are feasible without substantially departing from the teachings of the subject matter of the present invention. Accordingly, all such modifications should be included within the scope of the present invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, parameters, etc. of the following exemplary embodiments without departing from the gist of the present invention.

[0025] As Figure 1 shown, the titanium dioxide surface treatment process flow according to the present invention adds the collection and reuse process of the filtrate after titanium dioxide surface treatment on the basis of the prior art. The reuse device for the filtrate after titanium dioxide surface treatment obtained by transforming the existing equipment at least includes: a filtrate storage tank, at least one pipeline connected to the filtrate storage tank, and a pump provided on the pipeline. Specifically, the filtrate storage tank is connected to the filtration device after titanium dioxide surface treatment to collect the filtrate after surface treatment; at least one pipeline includes a first pipeline connecting the filtrate storage tank to the beating tank and a second pipeline connecting the filtrate storage tank to the coating tank, wherein both the beating tank and the coating tank are arranged upstream of the titanium dioxide surface treatment process; the pump is connected to the first pipeline and the second pipeline to selectively pump the filtrate after surface treatment to at least one of the beating tank and the coating tank.

[0026] The method for reusing the filtrate after titanium dioxide surface treatment using the above-mentioned transformed device generally includes the following steps:

[0027] 1) Collect the filtrate after titanium dioxide surface treatment into the filtrate storage tank.

[0028] 2) The filtrate after titanium dioxide surface treatment in the filtrate storage tank is pumped to the beating tank through the first pipeline and mixed with the titanium dioxide powder after roll pressing and beating to obtain a slurry. Preferably, the beating concentration of the filtrate after titanium dioxide surface treatment and the titanium dioxide powder is 400 - 1000 g / l.

[0029] 3) Wet grind the slurry. Among them, the wet grinding can include at least one of wet ball grinding and sand grinding.

[0030] 4) Pump the slurry after wet grinding into the coating tank.

[0031] 5) The filtrate after titanium dioxide surface treatment in the filtrate storage tank is pumped to the coating tank through the second pipeline to dilute the slurry after wet grinding and obtain a slurry after surface treatment through the surface treatment process. In the example of the present invention, the slurry after wet grinding is diluted to a concentration of 270 - 320 g / l.

[0032] Finally, the slurry after coating is filtered twice by the filtration device to obtain the filtrate after titanium dioxide surface treatment, and steps 1) - 5) are repeated to realize the recycling of the filtrate after titanium dioxide surface treatment.

[0033] Alternatively, considering the natural loss of the filtrate during the recycling process after the surface treatment of titanium dioxide, those skilled in the art can add an appropriate amount of fresh water (such as deionized water) to the beating tank and / or coating tank to obtain a predetermined slurry concentration.

[0034] The above preparation method of the present invention will be elaborated in detail through specific embodiments below.

[0035] Example 1

[0036] This embodiment shows a conventional filtrate treatment method:

[0037] (1) Collect the filtrate after the surface treatment of titanium dioxide into a filtrate storage tank;

[0038] (2) Use a pump to send the coated filtrate to a sedimentation device through a pipeline for sedimentation;

[0039] (3) The sedimented slurry is recycled into a slurry tank;

[0040] (4) The sedimented filtrate is discharged into a waste acid treatment system.

[0041] In the above process, the filtrate after sedimentation and separation still contains a small amount of titanium dioxide, with a content of about 0.1 g / L. After coating each ton of titanium dioxide, about 3 - 4 m 3 of filtrate is produced, resulting in a titanium dioxide loss of 0.03% - 0.04%, and at the same time, 3 - 4 m 3 of wastewater is generated.

[0042] Example 2

[0043] This embodiment shows a filtrate treatment method according to an embodiment of the present invention:

[0044] (1) Collect the filtrate after the surface treatment of titanium dioxide into a filtrate storage tank;

[0045] (2) Use a pump to connect the coated filtrate storage tank to a medium powder beating tank and a coating tank through a pipeline;

[0046] (3) Under stirring, mix the filtrate formed by the previous batch of surface treatment with titanium dioxide after roll pressing and grinding in a mass ratio of 2.24:1 to make a slurry with a concentration of about 400 g / l. Each ton of titanium dioxide consumes about 2.24 m 3 of filtrate;

[0047] (4) Perform processes such as wet ball milling and sand milling on the slurry to obtain a qualified sand milled slurry;

[0048] (5) Pump the sand milled slurry into a coating tank;

[0049] (6) Before coating, use the filtrate formed by the surface treatment of the previous batch to further dilute the concentration of the sanding slurry to 320 g / l. During the dilution process, about 0.62 m of filtrate is consumed per ton of titanium dioxide. 3 ;

[0050] (7) Conduct surface treatment according to the normal coating process to obtain the coated slurry.

[0051] (8) The coated slurry passes through a triple-wash diaphragm filter press to obtain a new filtrate, which is then re-collected into the filtrate storage tank.

[0052] The above process uses a lower beating concentration, consumes more filtrate during beating and less during dilution, but the total amount is basically equivalent to the filtrate generated by the coated slurry. There is no need to go through the sedimentation process, the filtrate is completely recovered, there will be no loss of titanium dioxide, no wastewater will be generated, and about 2.88 m of deionized water can be saved per ton of titanium dioxide. 3 。

[0053] Example 3

[0054] This embodiment shows a filtrate treatment method according to another embodiment of the present invention:

[0055] (1) Collect the filtrate after the surface treatment of titanium dioxide into the filtrate storage tank.

[0056] (2) Use a pump to connect the filtrate storage tank after coating to the medium powder beating tank and the coating tank through pipelines.

[0057] (3) Under stirring, mix and beat the filtrate formed by the surface treatment of the previous batch with the titanium dioxide after roll pressing in a mass ratio of 0.8:1 to form a slurry with a concentration of about 1000 g / l. About 0.8 m of filtrate is consumed per ton of titanium dioxide. 3 ;

[0058] (4) Conduct processes such as wet ball milling and sanding on the slurry to obtain a qualified sanding slurry.

[0059] (5) Pump the sanded slurry into the coating tank.

[0060] (6) Before coating, use the filtrate formed by the surface treatment of the previous batch to further dilute the concentration of the sanding slurry to 270 g / l. During the dilution process, about 2.7 m of filtrate is consumed per ton of titanium dioxide. 3 ;

[0061] (7) Conduct surface treatment according to the normal coating process to obtain the coated slurry.

[0062] (8) The coated slurry passes through a triple-wash diaphragm filter press to obtain a new filtrate, which is then re-collected into the filtrate storage tank.

[0063] The above process uses a relatively high beating consistency. The filtrate consumed in beating is less, while the filtrate consumed in dilution is more. However, the total amount is basically equivalent to the filtrate generated by the coating slurry. There is no need to go through the sedimentation process, and the filtrate is completely recovered, without causing the loss of titanium dioxide or generating wastewater. At the same time, about 3.5 m of deionized water can be saved per ton of titanium dioxide. 3 。

[0064] Comparing Examples 1 to 3, it can be seen that by using the process of the present invention, the loss of titanium dioxide can be reduced by 0.03% - 0.04%, and 2.8 - 3.5 m of deionized water can be saved per ton of titanium dioxide. 3 。

[0065] The above are the exemplary embodiments disclosed by the present invention. The order of disclosure of the above embodiments of the present invention is only for description and does not represent the superiority or inferiority of the embodiments. However, it should be noted that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of disclosure of the embodiments of the present invention (including the claims) is limited to these examples. Without departing from the scope defined by the claims, various changes and modifications can be made. The functions, steps, and / or actions of the method claims according to the disclosed embodiments here do not need to be performed in any specific order. In addition, although the elements disclosed in the embodiments of the present invention can be described or claimed in individual form, they can also be understood as multiple unless explicitly limited to the singular.

[0066] Those of ordinary skill in the art should understand that: the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other variations in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present invention shall be included in the protection scope of the embodiments of the present invention.

Claims

1. A device for recycling the filtrate after titanium white surface treatment, characterized in that, Comprising: A filtrate storage tank which is connected to a titanium white surface treatment filtration device to collect the filtrate after surface treatment; A first pipeline which connects the filtrate storage tank to a beating tank, and the beating tank is arranged upstream of the titanium white surface treatment process; A second pipeline which connects the filtrate storage tank to a coating tank, the coating tank is arranged upstream of the titanium white surface treatment process, and the surface treatment process obtains the coated slurry according to the coating process; And A pump which is connected to the first pipeline and the second pipeline to selectively pump the filtrate after surface treatment directly to at least one of the beating tank and the coating tank.

2. A method for recycling the filtrate after titanium white surface treatment, characterized in that, Comprising the following steps: 1) Collect the filtrate after titanium white surface treatment into the filtrate storage tank; 2) The filtrate after titanium white surface treatment in the filtrate storage tank is directly pumped to the beating tank through the first pipeline and mixed with titanium dioxide after roll pressing and grinding to obtain a slurry; 3) Wet grind the slurry; 4) Pump the wet-ground slurry into the coating tank; 5) The filtrate after titanium white surface treatment in the filtrate storage tank is directly pumped to the coating tank through the second pipeline to dilute the wet-ground slurry, and the coated slurry is obtained through the surface treatment process.

3. The method for recycling the filtrate after titanium dioxide surface treatment according to claim 2, characterized in that, In step 2), the beating concentration of the filtrate after titanium white surface treatment and the titanium dioxide is 400-1000 g / l.

4. The method for recycling the filtrate after titanium dioxide surface treatment according to claim 3, characterized in that, In step 3), the wet grinding includes at least one of wet ball milling and sand milling.

5. The method for recycling the filtrate after titanium dioxide surface treatment according to claim 4, characterized in that, In step 5), the wet-ground slurry is diluted to a concentration of 270-320 g / l.

6. The method for recycling the filtrate after titanium dioxide surface treatment according to claim 4, characterized in that, The coated slurry is filtered twice by a filtration device to obtain the filtrate after titanium white surface treatment, and steps 1)-5) are repeated to realize the recycling of the filtrate after titanium white surface treatment.

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