Method for preparing rutile titanium dioxide by using Ti-HMS catalyst production waste residues

Abstract

The invention belongs to the technical field of preparation of rutile titanium dioxide by solid waste resource recovery, and particularly relates to a method for preparing rutile titanium dioxide by using Ti-HMS catalyst production waste residues, which comprises the following steps: mixing the Ti-HMS catalyst production waste residues with an acid solution for acid treatment, washing with water, separating, and controlling the separated residues to keep acidic, thereby obtaining the rutile titanium dioxide. And then roasting to obtain the rutile type titanium dioxide. According to the method disclosed by the invention, the waste residues in Ti-HMS catalyst production can be subjected to resource utilization, the roasting temperature of the method is low, the obtained rutile type titanium dioxide has few defects and high quality, and the process is simple and easy to operate.

Description

Technical Field

[0001] The present invention belongs to the technical field of recycling solid waste to prepare rutile titanium dioxide, and specifically relates to a method for preparing rutile titanium dioxide by using waste residues produced in the production of Ti-HMS catalyst. Background Art

[0002] Ti-HMS catalyst is mainly used in reactions such as styrene epoxidation, cyclohexene epoxidation, and selective oxidation of p-tert-butyltoluene. During the preparation of Ti-HMS catalyst, waste gas is absorbed by lye to generate solid residues, and these solid residues will be disposed of as hazardous waste. The main components of this solid residue are: amorphous titanium dioxide (50 - 70 wt%), water (25 - 50 wt%), Fe 2 O 3 (2 - 6 wt%), Cr 2 O 3 (1 - 3 wt%), NiO (<1 wt%), SiO 2 (<1 wt%). Recycling this solid residue can avoid waste of titanium resources.

[0003] Titanium dioxide (TiO 2 ) is also known as titanium white. Titanium dioxide has three crystal structures, namely: rutile type, anatase type, and brookite type. Titanium dioxide can be applied in multiple fields such as photocatalysis, solar cells, coatings, and cosmetics. The preparation methods of rutile titanium dioxide include the sulfuric acid method or the chlorination method, but the calcination temperature required in these two methods is about one thousand degrees, resulting in more lattice defects, poor orientation, and large crystal grains in titanium dioxide.

[0004] For example, patent document CN1179888C discloses a nano rutile titanium dioxide and its preparation method, which requires adding a crystal form control agent, and this crystal form control agent remains in the final product and affects subsequent use; patent document CN1095808C discloses a rutile titanium dioxide and its preparation method, and the calcination temperature of this method is relatively high (850 - 1000 °C), and the high temperature will cause particles to sinter together, so the titanium dioxide particles prepared by this method are large; patent document CN115417451A discloses a method for preparing rutile titanium dioxide, and this method requires adding seeds with a complete rutile crystal form during the preparation process.

[0005] Therefore, there is a need for a method for preparing rutile with a low calcination temperature, a simple and easy-to-operate process, and without the need to add additional additives, and it can also recycle the solid waste generated during the production of Ti-HMS catalyst. Summary of the Invention

[0006] The object of the present invention is to provide a method for preparing rutile titanium dioxide from waste residues produced in the production of Ti-HMS catalysts. This method not only enables the resource utilization of waste residues from Ti-HMS catalyst production, but also features a low calcination temperature, resulting in rutile titanium dioxide with fewer defects and excellent quality, and a simple and easy-to-operate process.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing rutile titanium dioxide from waste residues produced in the production of Ti-HMS catalysts. First, the waste residues from Ti-HMS catalyst production are mixed with an acid solution for acid treatment, then washed with water and separated. The separated residue is controlled to remain acidic, and then calcined to obtain the rutile titanium dioxide.

[0009] In the method of the present invention, the waste residues generated in the process of producing Ti-HMS catalysts are resourcefully utilized. The waste residues are recovered and prepared into rutile titanium dioxide with relatively high purity and yield through special process conditions.

[0010] According to the method provided by the present invention, in some embodiments, the operation process of the acid treatment is as follows: The waste residues from Ti-HMS catalyst production are stirred and mixed with an acid solution. The mixing temperature is 5°C to 60°C (for example, 6°C, 10°C, 15°C, 20°C, 25°C, 30°C, 40°C, 50°C), and the mixing treatment time is 1 to 60 minutes (for example, 2 minutes, 4 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 40 minutes, 50 minutes).

[0011] In the present invention, the acid treatment process can not only remove non-Ti metal impurities contained in the waste residues, but also enable hydrogen ions to adsorb on the surface of amorphous titanium dioxide, promoting the crystal form transformation of titanium dioxide in the residues, changing it from amorphous to rutile type, and thus reducing the crystal form transformation temperature.

[0012] According to the method provided by the present invention, in some embodiments, the acid solution in the operation process of the acid treatment is selected from one or more of hydrochloric acid aqueous solution, nitric acid aqueous solution, and sulfuric acid aqueous solution.

[0013] In some embodiments, the concentration of the acid solution is 0.5 to 5 mol / L (for example, 0.8 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, 3.0 mol / L, 4.0 mol / L, 4.5 mol / L).

[0014] In some embodiments, the mixing mass ratio of the waste residue produced by the Ti-HMS catalyst to the acid solution is 1:(6-10), for example, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5.

[0015] In the method of the present invention, by keeping the residue obtained after water washing and separation acidic, the crystal form transformation of titanium dioxide in the residue can be promoted during calcination, promoting its transformation from amorphous to rutile type, and thus the crystal form transformation temperature can be reduced.

[0016] According to the method provided by the present invention, in some embodiments, after the product obtained by acid treatment is washed with water and separated, the pH value of the separated residue is 1-5, for example, 1, 5, 2, 3, 4, 4.5.

[0017] In the present invention, the purpose of water washing is to remove soluble salt impurities in the residue after acid treatment, but the water washing operation will also wash away a part of the acid in the system; in order to keep the residue acidic after water washing and separation, an acidic solution can be sprayed on the residue after water washing and separation to control its pH value within a suitable range.

[0018] In some embodiments, the operation method for controlling the pH value of the separated residue to be 1-5 is: spraying an acidic solution on the separated residue.

[0019] In some embodiments, the acidic solution is selected from one or more of aqueous hydrochloric acid solution, aqueous nitric acid solution and aqueous sulfuric acid solution.

[0020] In some embodiments, the concentration of the acidic solution is 5-15 mol / L (for example, 6 mol / L, 8 mol / L, 10 mol / L, 12 mol / L, 14 mol / L).

[0021] In some embodiments, the separated residue and the acidic solution are sprayed and mixed according to a mass ratio of (28-5):1, preferably (25-5):1 (for example, 6:1, 8:1, 10:1, 12:1, 15:1, 18:1, 20:1, 22:1, 24:1, 25:1, 26:1).

[0022] In some embodiments, the process conditions of the calcination include: the calcination temperature is 500-800 °C (for example, 550 °C, 600 °C, 650 °C, 700 °C, 750 °C), the calcination time is 1-4 h (for example, 1.5 h, 2.0 h, 2.5 h, 3.0 h, 3.5 h), the calcination heating rate is 5-20 °C / min (for example, 6 °C / min, 8 °C / min, 10 °C / min, 12 °C / min, 14 °C / min, 15 °C / min, 18 °C / min), and the calcination atmosphere is an air atmosphere.

[0023] The transformation temperature of the amorphous to rutile type is related to the raw materials, the treatment method, whether a crystal form promoter is added, and also to the type of the promoter. In the method of the present invention, waste solid resources are used as raw materials and no crystal form promoter is added; in the calcination process, the higher the calcination temperature, the easier it is for the amorphous to transform into the rutile type, but the higher the calcination temperature, the larger the titanium dioxide crystal grains formed; and the greater the calcination heating rate, the greater the grain defects. Therefore, controlling the calcination temperature and the calcination heating rate within a suitable range can make the prepared rutile type titanium dioxide have smaller grain sizes and fewer grain defects generated.

[0024] According to the method provided by the present invention, in some embodiments, the average grain size of the rutile type titanium dioxide is 45 - 70 nm (for example, 50 nm, 55 nm, 60 nm, 65 nm, 68 nm).

[0025] In the method of the present invention, by using the acid treatment process and making the residue before calcination acidic (pH value within a suitable range), the crystal form transformation of titanium dioxide can be promoted, and to a certain extent, the calcination temperature can be reduced. Both the acid treatment process and spraying an acidic solution on the residue before calcination can make hydrogen ions adsorbed on the surface of amorphous titanium dioxide, which can induce the transformation of amorphous titanium dioxide into rutile type titanium dioxide during calcination, and the excess acid in the residue will gradually volatilize as the temperature rises during calcination and will not remain in the final product.

[0026] Compared with the prior art, the beneficial effects obtained by the technical solution of the present invention are at least as follows:

[0027] In the present invention, by acid - treating the waste residue from the production of Ti - HMS catalyst, washing with water to remove metal salts in the residue, and controlling the residue after water - washing separation to be acidic, the acid attached to the residue during calcination can promote the transformation of amorphous titanium dioxide into rutile type titanium dioxide, which can reduce the transformation temperature of amorphous titanium dioxide into rutile type titanium dioxide, thereby reducing the calcination temperature and reducing lattice defects. The method of the present invention can not only successfully recycle the Ti - containing waste residue to obtain rutile type titanium dioxide, but also has a low calcination temperature, few defects in the obtained rutile type titanium dioxide product, and excellent quality (high purity, small particle size). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The operation process flow chart of the method according to one embodiment of the present invention is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] In order to be able to understand the technical features and content of the present invention in detail, the preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described in the examples, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. For those not specified in the examples, they are carried out under conventional conditions or conditions recommended by the manufacturer.

[0030] <Main raw material source>

[0031] The waste residue produced in the production of Ti-HMS catalyst is the residue generated during the production of Ti-HMS catalyst, which comes from the solid waste generated by Wanhua Chemical's catalyst device. The main components of this solid waste are: amorphous titanium dioxide (50 - 70 wt%), water (25 - 50 wt%), Fe 2 O 3 (2 - 6 wt%), Cr 2 O 3 (1 - 3 wt%), NiO (<1 wt%), SiO 2 (<1 wt%).

[0032] Other raw materials and reagents, unless otherwise specified, can be obtained through commercial channels.

[0033] The main equipment and testing methods used in the embodiments of the present invention are as follows:

[0034] Stirring is carried out using a Vigers overhead stirrer WB2000M;

[0035] The muffle furnace uses a Shanghai Guangshu Electromechanical GSQ-2-1200-II high-temperature muffle furnace;

[0036] The water bath uses a Shanghai Lingke Industrial ZNCL-GS intelligent magnetic (heating pot) stirrer;

[0037] XRD uses a Malvern Panalytical X’Pert 3 Powder X-ray diffractometer.

[0038]

Example 1

[0039] The method for preparing rutile titanium dioxide using the waste residue produced in the production of Ti-HMS catalyst is as follows, referring to the Figure 1 shown process:

[0040] Take 10 g of the waste residue generated during the production of the Ti-HMS catalyst, add 100 g of hydrochloric acid aqueous solution (the solute concentration in the hydrochloric acid aqueous solution is 2 mol / L), place it in an environment at 40 °C and stir and mix for 10 min for acid treatment; filter the residue after acid treatment, wash it with deionized water, and then spray 400 μL of nitric acid aqueous solution (the solute concentration in the nitric acid aqueous solution is 9 mol / L) on the residue separated by filtration to make the residue acidic and the pH value = 3; then calcine the acidic residue, and the calcination process conditions include: calcination temperature 650 °C, calcination time 3 h, calcination heating rate 10 °C, air atmosphere, to obtain the final product.

[0041]

Example 2

[0042] A method for preparing rutile titanium dioxide using the waste residue generated from the production of the Ti-HMS catalyst is as follows:

[0043] Take 10 g of the waste residue generated during the production of the Ti-HMS catalyst, add 80 g of nitric acid aqueous solution (the solute concentration in the nitric acid aqueous solution is 1 mol / L), place it in an environment at 30 °C and stir and mix for 30 min for acid treatment; filter the residue after acid treatment, wash it with deionized water, and then spray 400 μL of sulfuric acid aqueous solution (the solute concentration in the sulfuric acid aqueous solution is 5 mol / L) on the residue separated by filtration to make the residue acidic and the pH value = 5; then calcine the acidic residue, and the calcination process conditions include: calcination temperature 800 °C, calcination time 1 h, calcination heating rate 8 °C, air atmosphere, to obtain the final product.

[0044]

Example 3

[0045] A method for preparing rutile titanium dioxide using the waste residue generated from the production of the Ti-HMS catalyst is as follows:

[0046] Take 10 g of the waste residue generated during the production of the Ti-HMS catalyst, add 60 g of sulfuric acid aqueous solution (the solute concentration in the sulfuric acid aqueous solution is 3 mol / L), place it in an environment at 50 °C and stir and mix for 5 min for acid treatment; filter the residue after acid treatment, wash it with deionized water, and then spray 600 μL of hydrochloric acid aqueous solution (the solute concentration in the hydrochloric acid aqueous solution is 12 mol / L) on the residue after filtration to make the residue acidic and the pH value = 1; then calcine the acidic residue, and the calcination process conditions include: calcination temperature 500 °C, calcination time 2 h, calcination heating rate 15 °C, air atmosphere, to obtain the final product.

[0047]

Example 4

[0048] The method for preparing rutile titanium dioxide from the waste residue produced in the production of Ti-HMS catalyst refers to Example 2, with the differences that the type of acidic solution sprayed on the residue separated by suction filtration after washing with demineralized water is replaced by an aqueous nitric acid solution, and the heating rate during the calcination process is changed to 20 °C / min; the remaining steps and process conditions are the same as those in Example 2.

[0049]

Example 5

[0050] The method for preparing rutile titanium dioxide from the waste residue produced in the production of Ti-HMS catalyst refers to Example 1, with the difference that the heating rate during the calcination process is changed to 15 °C / min; the remaining steps and process conditions are the same as those in Example 1.

[0051]

Example 6

[0052] The method for preparing rutile titanium dioxide from the waste residue produced in the production of Ti-HMS catalyst refers to Example 2, with the differences that the type of acidic solution sprayed on the residue separated by suction filtration after washing with demineralized water is replaced by an aqueous hydrochloric acid solution, and the heating rate during the calcination process is changed to 5 °C / min; the remaining steps and process conditions are the same as those in Example 2.

[0053]

Comparative Example 1

[0054] The method for preparing rutile titanium dioxide from the waste residue produced in the production of Ti-HMS catalyst refers to Example 1, with the difference that after taking 10 g of the waste residue generated during the production of Ti-HMS catalyst, no acid treatment and spraying of acidic solution are carried out; that is: the waste residue raw material is directly washed and separated with demineralized water and then calcined. The calcination process conditions include: calcination temperature 650 °C, calcination time 3 h, heating rate 10 °C, air atmosphere, to obtain the final product.

[0055]

Comparative Example 2

[0056] The method for preparing rutile titanium dioxide from the waste residue produced in the production of Ti-HMS catalyst is as follows:

[0057] Take 10 g of the waste residue generated during the production of Ti-HMS catalyst, add 100 g of an aqueous hydrochloric acid solution (the solute concentration in the aqueous hydrochloric acid solution is 2 mol / L) thereto, place it in an environment at 40 °C and stir and mix for 10 min for acid treatment; filter the residue after acid treatment by suction filtration, wash it with demineralized water, and do not spray acidic solution on the residue obtained after suction filtration separation. The separated residue is neutral (pH value = 7); then calcine the neutral residue. The calcination process conditions include: calcination temperature 650 °C, calcination time 3 h, heating rate 10 °C, air atmosphere, to obtain the final product.

[0058]

Comparative Example 3

[0059] The method for preparing rutile titanium dioxide from the waste residue produced in the production of Ti-HMS catalyst is as follows:

[0060] Take 10 g of the waste residue produced in the production of Ti-HMS catalyst, add 100 g of hydrochloric acid aqueous solution (the solute concentration in the hydrochloric acid aqueous solution is 2 mol / L), place it in an environment of 40 °C and stir and mix for 10 min for acid treatment; filter the acid-treated residue by suction, wash it with demineralized water, and then spray 400 μL of nitric acid aqueous solution (the solute concentration in the nitric acid aqueous solution is 9 mol / L) on the residue separated by suction filtration to make the residue acidic and the pH value = 3; then calcine the acidic residue, and the calcination process conditions include: the calcination temperature is 400 °C, the calcination time is 3 h, the calcination heating rate is 10 °C, and the air atmosphere to obtain the final product.

[0061]

Comparative Example 4

[0062] The method for preparing rutile titanium dioxide from the waste residue produced in the production of Ti-HMS catalyst is as follows:

[0063] Take 10 g of the waste residue produced in the production of Ti-HMS catalyst, add 80 g of nitric acid aqueous solution (the solute concentration in the nitric acid aqueous solution is 1 mol / L), place it in an environment of 30 °C and stir and mix for 30 min for acid treatment; filter the acid-treated residue by suction, wash it with demineralized water, and then spray 400 μL of sulfuric acid aqueous solution (the solute concentration in the sulfuric acid aqueous solution is 5 mol / L) on the residue separated by suction filtration to make the residue acidic and the pH value = 5; then calcine the acidic residue, and the calcination process conditions include: the calcination temperature is 800 °C, the calcination time is 1 h, the calcination heating rate is 2 °C / min, and the air atmosphere to obtain the final product.

[0064]

Comparative Example 5

[0065] The method for preparing rutile titanium dioxide from the waste residue produced in the production of Ti-HMS catalyst is as follows:

[0066] Take 10 g of the waste residue produced in the production of Ti-HMS catalyst, add 80 g of nitric acid aqueous solution (the solute concentration in the nitric acid aqueous solution is 1 mol / L), place it in an environment of 30 °C and stir and mix for 30 min for acid treatment; filter the acid-treated residue by suction, wash it with demineralized water, and then spray 400 μL of sulfuric acid aqueous solution (the solute concentration in the sulfuric acid aqueous solution is 5 mol / L) on the residue separated by suction filtration to make the residue acidic and the pH value = 5; then calcine the acidic residue, and the calcination process conditions include: the calcination temperature is 800 °C, the calcination time is 1 h, the calcination heating rate is 25 °C / min, and the air atmosphere to obtain the final product.

[0067] The final products obtained in Examples 1-6 and Comparative Examples 1-5 were subjected to XRD qualitative and quantitative analysis tests, and the test calculation results are shown in Table 1.

[0068] Table 1 Analysis results of the final products obtained in Examples 1-6 and Comparative Examples 1-5

[0069]

[0070]

[0071] It can be seen from the experimental results in Table 1 that the technical solution of the present invention can resourcefully utilize the waste residue produced in the production of Ti-HMS catalyst while obtaining rutile titanium dioxide with few product defects and excellent quality (high purity and small particle size) by means of acid treatment, controlling the pH value of the residue after water washing and separation and before calcination within a suitable range, and selecting appropriate calcination process conditions.

[0072] In Comparative Example 1, the waste residue produced during the production of Ti-HMS catalyst was not acidified and the residue was neutral before calcination. The obtained final product not only had a high content of anatase titanium dioxide but also contained other impurity components. In Comparative Example 2, although the waste residue produced in the production of Ti-HMS catalyst was acidified, the pH value of the residue before calcination was not controlled within a suitable range, and the crystal form transformation was incomplete. The obtained final product had a high content of anatase titanium dioxide. In Comparative Example 3, the selected calcination temperature was too low. In Comparative Examples 4-5, the selected calcination heating rate was inappropriate, which would have an adverse effect on the crystal form transformation of titanium dioxide or cause grain defects and an increase in grain size.

[0073] The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the gist of the present invention.

Claims

1. A method for preparing rutile titanium dioxide using waste residue from Ti-HMS catalyst production, characterized in that: The waste residue from the production of Ti-HMS catalyst is first mixed with an acid solution for acid treatment, then washed with water and separated, the residue after separation is controlled to maintain acidity, and then roasted to obtain the rutile titanium dioxide.

2. The method according to claim 1, characterized in that The operation process of the acid treatment is: stirring and mixing the Ti-HMS catalyst production waste residue with an acid solution, the mixing temperature is 5° C. to 60° C., and the mixing treatment time is 1 to 60 minutes.

3. The method according to claim 1 or 2, characterized in that: The acid solution in the acid treatment process is selected from one or more of a hydrochloric acid aqueous solution, a nitric acid aqueous solution and a sulfuric acid aqueous solution; The concentration of the acid solution is 0.5-5 mol / L.

4. The method according to any one of claims 1 to 3, characterized in that The mixing mass ratio of the Ti-HMS catalyst production waste residue to the acid solution is 1:(6-10).

5. The method according to any one of claims 1 to 4, characterized in that The product obtained by acid treatment is washed with water and separated, and the pH value of the residue after separation is 1-5.

6. The method according to claim 5, characterized in that The operation method for controlling the pH value of the residue after separation to be 1 to 5 is as follows: spraying an acidic solution on the residue obtained after separation.

7. The method according to claim 6, characterized in that The acidic solution is selected from one or more of a hydrochloric acid aqueous solution, a nitric acid aqueous solution and a sulfuric acid aqueous solution; The concentration of the acidic solution is 5 to 15 mol / L.

8. The method according to claim 6 or 7, characterized in that: The residue obtained after separation is sprayed and mixed with the acidic solution in a mass ratio of (28-5):1, preferably (25-5):

1.

9. The method according to any one of claims 1 to 8, characterized in that The calcination process conditions include: a calcination temperature of 500-800° C., a calcination time of 1-4 hours, a calcination heating rate of 5-20° C. / min, and an air atmosphere.

10. The method according to any one of claims 1 to 9, characterized in that The average grain size of the rutile titanium dioxide is 45-70 nm.

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