Method for reducing pulping viscosity of titanium dioxide chloride primary product slurry

Abstract

The invention provides a treatment method of a titanium dioxide primary product slurry in a chlorination process titanium dioxide process, which comprises the following steps: feeding a titanium dioxide primary product produced by a chlorination process into water in a beating tank, mixing to obtain a mixture, adding hydrogen peroxide, and continuously mixing to obtain a slurry; washing and filter-pressing the slurry obtained in the previous step to obtain a filter cake; and mixing the filter cake obtained in the previous step with water, and adding a pH regulator to obtain the pulped titanium dioxide slurry. The method can ensure that the viscosity of the slurry is relatively low, meets the requirements of a sanding process, does not need to additionally add a dispersing agent, reduces the consumption of hydrogen peroxide and caustic soda flakes, thoroughly cleans sodium and chloride ions in a titanium dioxide chloride primary product, reduces the ion concentration in the titanium dioxide slurry, solves the problems of high pulping viscosity and poor sanding effect, reduces the sanding cost, and improves the production efficiency. The product quality is improved to a certain extent, and the problem that the content of impurity elements in titanium dioxide is unstable can be avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of treatment of primary titanium dioxide chloride slurry, and relates to a treatment method and application of primary titanium dioxide slurry in a chloride titanium dioxide process, and in particular to a method for reducing the beating viscosity of primary titanium dioxide chloride slurry. Background Art

[0002] Titanium dioxide is a white inorganic pigment with excellent performance, which is widely used in coatings, plastics, papermaking, inks, cosmetics, food additives, electronics and other fields. The chlorination process produces titanium dioxide with rutile and titanium slag as raw materials, and obtains the primary titanium dioxide through chlorination and oxidation. In order to improve the application performance of titanium dioxide, the primary titanium dioxide obtained needs to be post-processed. The post-processing process is long and generally includes pulping, sanding, inorganic surface treatment, three washings, drying, organic treatment, steam powder, packaging and other processes.

[0003] In the chloride process titanium dioxide production industry, the pulping process mainly involves dissolving the primary titanium dioxide collected by the bag filter together with desalted water in a pulping tank to make a solid-liquid pulp. The pulped slurry is directly transported to the dechlorination tank by pressure. A certain amount of hydrogen peroxide is added to the filter tank to remove the residual chlorine. The slurry then enters a sand mill and zirconium beads are added for grinding and crushing. The qualified slurry is de-coated, and the unqualified slurry is returned to the sand mill for re-grinding.

[0004] The effect of sand grinding is affected by the viscosity of the slurry. When the viscosity of the slurry is too high, the sand grinding effect is poor and the wear of the sand mill is aggravated. In production, when the viscosity of the slurry is too high, a certain amount of dispersant can be added, or the amount of sand grinding zirconium beads can be increased, but these two methods cannot fundamentally solve the problem. The viscosity of titanium dioxide slurry is mainly affected by pH, slurry concentration, and composition. At present, the traditional method of beating the primary titanium dioxide is to control the pH at 9.5-10.5, and the beating and dispersion are carried out under stirring. However, due to the influence of the previous process, the ion concentration in the slurry is too high, which will cause the slurry viscosity to rise and it is difficult to take measures to reduce it.

[0005] Therefore, how to find a more suitable method to reduce the viscosity of the primary slurry of titanium dioxide chloride and solve the above-mentioned technical problems existing in the existing process has become one of the urgent problems to be solved by many front-line researchers in the industry. Summary of the invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a method for treating the primary titanium dioxide slurry in the chloride titanium dioxide process and its application, in particular, a method for reducing the viscosity of the primary titanium dioxide slurry. The treatment method provided by the present invention can ensure that the slurry viscosity is low, meet the requirements of the sand milling process, do not require the addition of additional dispersants, and reduce the consumption of hydrogen peroxide and caustic soda; at the same time, the treatment method has a simple process, good controllability, strong operability, and is more suitable for industrial promotion and application.

[0007] The present invention provides a method for treating primary titanium dioxide slurry in a chloride titanium dioxide process, comprising the following steps:

[0008] 1) adding the primary titanium dioxide produced by the chloride process into water in a pulping tank for mixing to obtain a mixture, and then adding hydrogen peroxide and continuing to mix to obtain a slurry;

[0009] 2) washing and filtering the slurry obtained in the above step to obtain a filter cake;

[0010] 3) The filter cake obtained in the above step is mixed with water, and a pH regulator is added to obtain a titanium dioxide slurry after pulping.

[0011] Preferably, the titanium dioxide primary product is specifically a titanium dioxide primary product obtained after chlorination and oxidation in the chloride titanium dioxide process;

[0012] The mixing method includes stirring and mixing;

[0013] The concentration of the mixture is 340-400 g / L.

[0014] Preferably, the hydrogen peroxide is specifically a hydrogen peroxide solution;

[0015] The mass concentration of the hydrogen peroxide solution is 25% to 30%;

[0016] The volume ratio of the hydrogen peroxide solution to the mixture is 0.2% to 0.5%.

[0017] Preferably, the mixing time is greater than or equal to 1 hour;

[0018] The pH value of the slurry is 1-8.

[0019] Preferably, the washing device comprises a diaphragm washing device;

[0020] The washing method includes washing with water.

[0021] Preferably, the concentration of the mixed slurry is 300-450 g / L.

[0022] Preferably, the pH adjuster comprises NaOH;

[0023] The pH value of the titanium dioxide slurry after beating is 7.5-10.5.

[0024] Preferably, the mass content of Na element in the titanium dioxide slurry after beating is 0.05% to 1%;

[0025] The mass content of Cl element in the titanium dioxide slurry after beating is 0.05% to 2%;

[0026] The treatment method further comprises the step of sand grinding the titanium dioxide slurry after pulping;

[0027] The D90 particle size of the slurry after sand grinding is 0.6-1.2 μm.

[0028] Preferably, the treatment method is specifically a treatment method for reducing the viscosity of the primary titanium dioxide slurry;

[0029] The viscosity of the titanium dioxide slurry after slurrying is 200-400 cP.

[0030] The present invention also provides the application of the treatment method described in any one of the above technical solutions in reducing the viscosity of titanium dioxide primary slurry in the chloride process titanium dioxide process.

[0031] The present invention provides a method for treating a primary titanium dioxide slurry in a chloride titanium dioxide process, comprising the following steps: first, the primary titanium dioxide produced by the chloride process is sent into water in a pulping tank for mixing to obtain a mixture, and then hydrogen peroxide is added for further mixing to obtain a slurry; then the slurry obtained in the above steps is washed and filtered to obtain a filter cake; finally, the filter cake obtained in the above steps is mixed with water, and a pH regulator is added to obtain a titanium dioxide slurry after pulping. Compared with the prior art, the method for treating a primary titanium dioxide slurry with specific steps designed by the present invention is a method that can reduce the pulping viscosity of the primary titanium dioxide slurry. The present invention controls the steps and the addition of reagents, and washes the slurry at the same time, thereby completely removing impurity ions in the titanium dioxide slurry, ensuring the subsequent sanding effect, obtaining titanium dioxide with uniform particle size distribution, strengthening the coating quality, and improving the quality of the post-processing product as a whole.

[0032] The treatment method provided by the present invention can ensure that the slurry viscosity is low, meet the requirements of the sand milling process, do not need to add additional dispersants, and reduce the consumption of hydrogen peroxide and caustic soda. In addition, the sodium and chloride ions in the primary product of titanium dioxide chloride are thoroughly washed away, the ion concentration in the titanium dioxide slurry is reduced, the problem of high viscosity and poor sand milling effect is solved, the equipment and material costs of the sand milling process are reduced, the product quality is improved to a certain extent, and the problem of unstable impurity element content of titanium dioxide caused by the previous process can be eliminated. The on-site equipment modification is simple and easy to implement, and can be fully promoted in titanium dioxide enterprises with demand. DETAILED DESCRIPTION

[0033] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention rather than limiting the patent claims of the present invention.

[0034] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0035] There is no particular limitation on the purity of all raw materials in the present invention. The present invention preferably uses industrial purity or conventional purity in the field of primary slurry treatment of titanium dioxide chloride.

[0036] The brands and abbreviations of all raw materials of the present invention are conventional brands and abbreviations in the art. Each brand and abbreviation is clear and definite in the field of its related use. Those skilled in the art can purchase them from the market or prepare them by conventional methods according to the brands, abbreviations and corresponding uses.

[0037] The present invention provides a method for treating primary titanium dioxide slurry in a chloride titanium dioxide process, comprising the following steps:

[0038] 1) adding the primary titanium dioxide produced by the chloride process into water in a pulping tank for mixing to obtain a mixture, and then adding hydrogen peroxide and continuing to mix to obtain a slurry;

[0039] 2) washing and filtering the slurry obtained in the above step to obtain a filter cake;

[0040] 3) The filter cake obtained in the above step is mixed with water, and a pH regulator is added to obtain a titanium dioxide slurry after pulping.

[0041] The present invention firstly feeds the primary titanium dioxide produced by the chlorination method into the water in the pulping tank for mixing to obtain a mixture, then adds hydrogen peroxide for further mixing to obtain a slurry.

[0042] In the present invention, the titanium dioxide primary product is preferably a titanium dioxide primary product obtained by chlorination and oxidation in a chloride titanium dioxide process.

[0043] In the present invention, the mixing method preferably includes stirring and mixing.

[0044] In the present invention, the concentration of the mixture is preferably 340-400 g / L, more preferably 350-390 g / L, more preferably 360-380 g / L, specifically 350 g / L or 360 g / L.

[0045] In the present invention, the hydrogen peroxide is preferably a hydrogen peroxide solution.

[0046] In the present invention, the mass concentration of the hydrogen peroxide solution is preferably 25% to 30%, more preferably 26% to 29%, more preferably 27% to 28%, and specifically 27.5%.

[0047] In the present invention, the volume ratio of the hydrogen peroxide solution to the mixture is preferably 0.2% to 0.5%, more preferably 0.25% to 0.45%, and more preferably 0.3% to 0.4%.

[0048] In the present invention, the time for continued mixing is preferably greater than or equal to 1 hour, more preferably greater than or equal to 1.5 hours, and more preferably greater than or equal to 2 hours.

[0049] In the present invention, the pH value of the slurry is preferably 1-8, more preferably 2-7, more preferably 3-6, and more preferably 4-5.

[0050] In the present invention, the slurry obtained in the above steps is washed and filtered to obtain a filter cake.

[0051] In the present invention, the washing device preferably includes a diaphragm washing device.

[0052] In the present invention, the washing method preferably includes washing with water.

[0053] Finally, the filter cake obtained in the above steps is mixed with water, and a pH regulator is added to obtain a slurried titanium dioxide slurry.

[0054] In the present invention, the concentration of the mixed slurry is preferably 300 to 450 g / L, more preferably 330 to 420 g / L, and more preferably 360 to 390 g / L.

[0055] In the present invention, the pH adjuster preferably includes NaOH.

[0056] In the present invention, the pH value of the titanium dioxide slurry after beating is preferably 7.5 to 10.5, more preferably 8 to 10, and more preferably 8.5 to 9.5.

[0057] In the present invention, the mass content of Na element in the titanium dioxide slurry after beating is preferably 0.05% to 1%, more preferably 0.09% to 0.5%, more preferably 0.09% to 0.1%, specifically 0.09%.

[0058] In the present invention, the mass content of Cl element in the titanium dioxide slurry after beating is preferably 0.05% to 2%, more preferably 0.08% to 0.17%, more preferably 0.11% to 0.14%, and specifically 0.14%.

[0059] In the present invention, the treatment method preferably further comprises the step of sand grinding the slurried titanium dioxide slurry.

[0060] In the present invention, the D90 particle size of the slurry after sand grinding is preferably 0.6-1.2 μm, more preferably 0.7-1.1 μm, more preferably 0.8-1.0 μm, and specifically 0.8017 μm.

[0061] In the present invention, the treatment method is preferably a treatment method for reducing the viscosity of the primary titanium dioxide slurry.

[0062] In the present invention, the viscosity of the titanium dioxide slurry after beating is preferably 200 to 400 cP, more preferably 240 to 350 cP, more preferably 240 to 300 cP, and specifically may be 240 cP.

[0063] The present invention provides an application of the treatment method described in any one of the above technical solutions in reducing the viscosity of titanium dioxide primary slurry in a chloride titanium dioxide process.

[0064] The present invention is a complete and detailed overall technical solution, which can better reduce the viscosity of the primary titanium dioxide slurry and further improve the quality of subsequent titanium dioxide products. The method for reducing the viscosity of the primary titanium dioxide chloride slurry specifically includes the following steps:

[0065] 1) adding deionized water into the beating tank, starting stirring, and at the same time, adding the primary product of titanium dioxide chloride into the beating tank at a uniform speed, adjusting the ratio of the primary product to water, and continuing stirring to obtain the primary product of titanium dioxide chloride slurry;

[0066] 2) Add a small amount of hydrogen peroxide (<0.5%) and continue stirring for more than 1 hour;

[0067] 3) The slurry is introduced into a membrane washing device, washed with 1 times desalted water, and filtered to obtain a filter cake;

[0068] 4) The filter cake is re-slurried to obtain a titanium dioxide primary slurry with a certain concentration (300 g / L to 450 g / L);

[0069] 5) adding NaOH to adjust the slurry pH to 7.5-10.5;

[0070] 6) The slurry enters the sand mill for sand grinding.

[0071] After the present invention adopts the above-mentioned inventive process, the viscosity of the slurry can be ensured to be low, the requirements of the sand grinding process can be met, no additional dispersant needs to be added, and the consumption of hydrogen peroxide and caustic soda can be reduced.

[0072] The above content of the present invention provides a method and application for reducing the viscosity of the primary slurry of titanium dioxide chloride. The method for treating the primary slurry of titanium dioxide with specific steps designed by the present invention is a method that can reduce the viscosity of the primary slurry of titanium dioxide chloride. The present invention controls the steps and the addition of reagents, and washes the slurry at the same time, thereby completely removing the impurity ions in the titanium dioxide slurry, ensuring the subsequent sanding effect, obtaining titanium dioxide with uniform particle size distribution, strengthening the coating quality, and improving the overall quality of the post-processing product.

[0073] The treatment method provided by the present invention can ensure that the slurry viscosity is low, meet the requirements of the sand milling process, do not need to add additional dispersants, and reduce the consumption of hydrogen peroxide and caustic soda. In addition, the sodium and chloride ions in the primary product of titanium dioxide chloride are thoroughly washed away, the ion concentration in the titanium dioxide slurry is reduced, the problem of high viscosity and poor sand milling effect is solved, the equipment and material costs of the sand milling process are reduced, the product quality is improved to a certain extent, and the problem of unstable impurity element content of titanium dioxide caused by the previous process can be eliminated. The on-site equipment modification is simple and easy to implement, and can be fully promoted in titanium dioxide enterprises with demand.

[0074] In order to further illustrate the present invention, the treatment method and application of the primary titanium dioxide slurry in the chloride titanium dioxide process provided by the present invention are described in detail in combination with the embodiments below. However, it should be understood that these embodiments are implemented on the premise of the technical scheme of the present invention, and detailed implementation methods and specific operating processes are given only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention, and the protection scope of the present invention is not limited to the following embodiments.

[0075] Example 1

[0076] Take the initial chlorinated product and add it to desalted water to prepare titanium dioxide slurry with a concentration of 350g / L. After adding hydrogen peroxide for dechlorination, the pH is 2.8. NaOH and dispersant are added to adjust the pH to 9.5. After sufficient stirring, it is put into a sand mill for sand grinding (sand mill speed 3000r / min, sand mill filling rate 80%, sand feed pump speed 1).

[0077] Example 2

[0078] The chlorinated primary product was added to desalted water to prepare titanium dioxide slurry with a concentration of 360 g / L. A small amount of hydrogen peroxide was added for dechlorination. The pH after dechlorination was 3.9. Then water was added for washing and filter pressing. The filter cake was re-slurried to prepare titanium dioxide slurry with a concentration of 340 g / L. The pH was adjusted to 9.5 and the slurry was put into a sand mill for sand grinding. The sand grinding conditions were the same as those in Example 1.

[0079] The above two examples are compared, and the results are as follows:

[0080] See Table 1, which shows the slurry comparison results in the examples of the present invention.

[0081] Table 1

[0082] Na% Cl％ Viscosity / cP Example 1 1.24 5.34 510 Example 2 0.09 0.14 240

[0083] See Table 2, which shows the particle size results after sand grinding in the embodiments of the present invention.

[0084] Table 2

[0085] D10 D50 D90 Example 1 0.9128μm 1.5776μm 7.5024μm Example 2 0.2194μm 0.3699μm 0.8017μm

[0086] From the comparison of the above embodiments, it can be seen that the titanium dioxide slurry after washing has better properties and better sanding effect.

[0087] The above is a detailed introduction to a method for reducing the viscosity of the primary slurry of titanium dioxide chloride provided by the present invention. The principles and implementation methods of the present invention are explained in this article using specific examples. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enables any technician in the field to practice the present invention, including the manufacture and use of any device or system, and the implementation of any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for treating primary titanium dioxide slurry in a chloride titanium dioxide process, characterized in that: The following steps are involved: 1) adding the primary titanium dioxide produced by the chloride process into water in a pulping tank for mixing to obtain a mixture, and then adding hydrogen peroxide and continuing to mix to obtain a slurry; 2) washing and filtering the slurry obtained in the above step to obtain a filter cake; 3) The filter cake obtained in the above step is mixed with water, and a pH regulator is added to obtain a titanium dioxide slurry after pulping.

2. The processing method according to claim 1, characterized in that: The titanium dioxide primary product is specifically a titanium dioxide primary product obtained after chlorination and oxidation in the chloride titanium dioxide process; The mixing method includes stirring and mixing; The concentration of the mixture is 340-400 g / L.

3. The processing method according to claim 1, characterized in that: The hydrogen peroxide is specifically a hydrogen peroxide solution; The mass concentration of the hydrogen peroxide solution is 25% to 30%; The volume ratio of the hydrogen peroxide solution to the mixture is 0.2% to 0.5%.

4. The processing method according to claim 1, characterized in that: The mixing time is greater than or equal to 1 hour; The pH value of the slurry is 1-8.

5. The processing method according to claim 1, characterized in that: The washing device comprises a diaphragm washing device; The washing method includes washing with water.

6. The processing method according to claim 1, characterized in that: The concentration of the mixed slurry is 300-450 g / L.

7. The processing method according to claim 1, characterized in that: The pH adjuster includes NaOH; The pH value of the titanium dioxide slurry after beating is 7.5-10.

5.

8. The processing method according to claim 1, characterized in that: The mass content of Na element in the titanium dioxide slurry after beating is 0.05% to 1%; The mass content of Cl element in the titanium dioxide slurry after beating is 0.05% to 2%; The treatment method further comprises the step of sand grinding the titanium dioxide slurry after pulping; The D90 particle size of the slurry after sand grinding is 0.6-1.2 μm.

9. The processing method according to claim 1, characterized in that: The treatment method is specifically a treatment method for reducing the viscosity of the primary titanium dioxide slurry; The viscosity of the titanium dioxide slurry after slurrying is 200-400 cP.

10. Use of the treatment method according to any one of claims 1 to 9 in reducing the viscosity of primary titanium dioxide slurry in a chloride titanium dioxide process.