CN115417451B - Method for preparing rutile titanium dioxide - Google Patents

Abstract

The invention discloses a method for preparing rutile titanium dioxide, which comprises the following steps: mixing the calcined seed crystal and the hydrolyzed titanium solution; carrying out hydrolysis; filtering and washing the hydrolyzed slurry to obtain the metatitanic acid. According to the method for preparing rutile titanium dioxide, provided by the invention, the calcining seed crystal is added into the hydrolysis process instead of the hydrolysis seed crystal, so that the calcining seed crystal is not added in the process of washing the meta-titanic acid in advance and later, the process of preparing the hydrolysis seed crystal is omitted, and the second washing process in the process of washing the meta-titanic acid is omitted, namely, only one washing process is needed in the process of washing the meta-titanic acid, thereby greatly saving energy and raw material consumption in the whole process and greatly reducing the production cost.

Description

Method for preparing rutile titanium dioxide

Technical field

The present invention relates to the technical field of titanium dioxide production, and in particular to a method for preparing rutile titanium dioxide.

Background technique

Titanium dioxide (titanium dioxide) is chemically stable and does not react with most substances under normal circumstances. There are three kinds of crystals of titanium dioxide in nature: plate titanium type, anatase type and rutile type. Among them, rutile type titanium dioxide is currently the best white inorganic pigment in the world and is widely used in coatings, plastics, papermaking, and printing inks. , chemical fiber, rubber, ceramics, cosmetics, food additives and medicine and other fields.

At present, in the production process of titanium dioxide by sulfuric acid method, it is generally necessary to prepare hydrolyzed seed crystals separately and add them during the hydrolysis process. The acidic slurry obtained by hydrolysis is washed with water. The water washing process is to add calcined seed crystals after one washing, and then wash them twice. , and then undergo salt treatment and calcination to obtain rutile titanium dioxide. However, the production process requires separate preparation of hydrolyzed seed crystals and calcined seed crystals, and the crude metaacid obtained by hydrolysis needs to be washed twice, which brings about problems of high energy and raw material consumption and high production costs.

Based on this, there is a need to improve the method for preparing rutile titanium dioxide.

Contents of the invention

In order to solve the above technical problems, the present invention proposes a method for preparing rutile titanium dioxide, which can solve the problem that in the existing sulfuric acid method titanium dioxide production process, due to the need to separately prepare hydrolyzed seed crystals and calcined seed crystals, the crude metaacid obtained by hydrolysis needs to be prepared twice. Washing has brought about the problems of high energy and raw material consumption and high production costs.

The embodiment of the present invention discloses a method for preparing rutile titanium dioxide, which includes the following steps:

Mix the calcined seed crystal and hydrolyzed titanium liquid;

undergo hydrolysis;

Filter and wash the hydrolyzed slurry to prepare metatitanic acid.

According to one embodiment of the present invention, the prepared metatitanic acid is treated with salt and calcined at 800°C to prepare rutile titanium dioxide.

According to an embodiment of the present invention, the method of mixing the calcined seed crystal and the hydrolyzed titanium liquid is:

The calcined seed crystal and the hydrolyzed titanium liquid are respectively preheated to 60-98°C and then mixed; or,

Preheat the calcined seed crystal to 60-98°C and then mix it with the hydrolyzed titanium liquid; or,

The hydrolyzed titanium liquid is preheated to 60-98°C and then mixed with the calcined seed crystal.

According to one embodiment of the present invention, the total titanium content of the hydrolyzed titanium liquid is 130-220g/L in terms of the amount of titanium dioxide, the iron-titanium ratio of the hydrolyzed titanium liquid is 0.15-0.45, and the F value of the hydrolyzed titanium liquid is 1.50 ~2.10; the total titanium content of the calcined seed crystal is 80-140g/L based on the amount of titanium dioxide.

According to one embodiment of the present invention, the added amount of the calcined seed crystal is 2% to 5.5% based on the ratio of the total titanium content of the calcined seed crystal and the total titanium content of the hydrolyzed titanium liquid.

According to an embodiment of the present invention, the hydrolysis includes: heating the mixed calcined seed crystal and the hydrolyzed titanium liquid to boiling, maintaining the temperature in the boiling state for 30 to 40 minutes, and then stopping heating and stirring for 30 minutes. Then turn on the heating and stirring to increase the temperature to boiling, and keep it warm for 3.5 hours to complete the hydrolysis.

According to an embodiment of the present invention, the hydrolysis is performed at normal pressure or under pressure.

According to one embodiment of the present invention, the iron ion concentration in the metatitanic acid prepared by filtering and washing is less than 30 ppm.

Adopting the above technical solutions, the present invention at least has the following beneficial effects:

In the method for preparing rutile titanium dioxide provided by the invention, calcined crystal seeds are added to the hydrolysis process instead of hydrolyzed crystal seeds, so that the adding process of calcined crystal seeds is advanced and calcined crystal seeds are no longer added during the water washing process of metatitanic acid at a later stage, minus The process of preparing hydrolyzed seed crystals is eliminated, and the second washing process in the metatitanic acid washing process is omitted. That is, only one washing is required in the metatitanic acid washing process, thus greatly saving energy and energy in the entire process. The consumption of raw materials greatly reduces production costs.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic flow chart of a method for preparing rutile titanium dioxide disclosed in an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings.

It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are to distinguish two entities or parameters with the same name but not the same, so it can be seen that "first" and "second" It is only for the convenience of description and should not be understood as a limitation on the embodiments of the present invention, and subsequent embodiments will not describe this one by one.

As shown in Figure 1, one embodiment of the present invention discloses a method for preparing rutile titanium dioxide, which includes the following steps:

Mix the calcined seed crystal and hydrolyzed titanium liquid;

undergo hydrolysis;

Filter and wash the hydrolyzed slurry to prepare metatitanic acid;

The calcined seed crystal described in the embodiment of the present invention is a crystal with a complete rutile crystal form, which can be produced through a conventional preparation process.

In some embodiments, the prepared metatitanic acid is treated with salt and calcined at 800°C to prepare rutile titanium dioxide.

In some embodiments, the method of mixing the calcined seed crystal and the hydrolyzed titanium liquid is: preheat the calcined seed crystal and the hydrolyzed titanium liquid to 60-98°C respectively and then mix; or, preheat the calcined seed crystal to 60-98°C. 98℃ and then mix it with the hydrolyzed titanium liquid; or, preheat the hydrolyzed titanium liquid to 60-98℃ and then mix it with the calcined seed crystal.

In some embodiments, the total titanium content of the hydrolyzed titanium liquid is 130 to 220 g/L based on the amount of titanium dioxide, the iron to titanium ratio of the hydrolyzed titanium liquid is 0.15 to 0.45, and the F value of the hydrolyzed titanium liquid is 1.50 to 2.10; the total titanium content of the calcined seed crystal is The content is 80-140g/L based on the amount of titanium dioxide.

In some embodiments, the amount of calcined seed crystal added is 2% to 5.5% based on the ratio of the total titanium content of the calcined seed crystal to the total titanium content of the hydrolyzed titanium liquid.

In some embodiments, hydrolysis includes: heating the mixed calcined seed crystal and hydrolyzed titanium liquid to boiling, keeping it in the boiling state for 30 to 40 minutes, then stopping heating and stirring for 30 minutes, and then turning on heating and stirring again to raise the temperature to boiling. , the hydrolysis is completed after being kept warm for 3.5 hours.

In some embodiments, the hydrolysis is performed as atmospheric hydrolysis or pressure hydrolysis.

In some embodiments, the iron ion concentration in the metatitanic acid produced by filtering and washing is less than 30 ppm.

Through the method for preparing rutile titanium dioxide disclosed in an embodiment of the present invention, the following Example 1, Example 2 and Example 3 are carried out, and through the hydrolysis rates of Example 1, Example 2 and Example 3, the obtained metatitanium The properties of the acid, the hydrolysis rate of conventional hydrolysis, and the properties of the metatitanic acid produced are analyzed to illustrate the advantages of the present invention.

Example 1

Add 22 mL of calcined seed crystal with a titanium dioxide content of 95 g/L into the four-necked flask and stir. Add 200 mL of titanium liquid preheated to 95°C (total titanium 194g/L, F value 1.85, iron to titanium ratio 0.17) into the four-necked flask. After mixing evenly, raise the temperature to boiling, keep it warm for 30 minutes in the boiling state, turn off the heating and stir for 30 minutes, then turn on the heating and stirring to raise the temperature to boiling, keep it warm for 3.5 hours to complete the hydrolysis, and filter and wash the slurry to obtain metatitanic acid. The hydrolysis rates of the examples and the properties of the metatitanic acid obtained are shown in Table 1.

Example 2

Add 6.2mL of calcined seed crystal with titanium dioxide content of 100g/L into the four-necked flask, stir and heat to 70 degrees Celsius, add 200mL of room temperature titanium liquid (total titanium 155g/L, F value 1.95, iron to titanium ratio 0.27) into the four-necked flask. After mixing evenly, raise the temperature to boiling, keep it in the boiling state for 40 minutes, turn off the heating and stir for 30 minutes, then turn on the heating and stirring to raise the temperature to boiling, and keep it for 3.5 hours. The hydrolysis is completed. The slurry after the completion is filtered and washed to obtain metatitanic acid. The hydrolysis rates of the examples and the properties of the metatitanic acid obtained are shown in Table 1.

Example 3

Add 11.5mL of calcined seed crystal with a titanium dioxide content of 108g/L into a four-necked flask, stir and heat to 70°C, and add 200mL of titanium liquid preheated to 85°C (total titanium 155g/L, F value 1.75, iron to titanium ratio 0.38). In the neck bottle, mix evenly and then raise the temperature to boiling. Keep it in the boiling state for 35 minutes. Turn off the heating and stir for 30 minutes. Then turn on the heating and stirring to raise the temperature to boiling. Keep it warm for 3.5 hours to complete the hydrolysis. The slurry after completion is filtered and washed to obtain partial Titanic acid, the hydrolysis rate of this example and the properties of the metatitanic acid obtained are shown in Table 1.

Table 1

It can be seen from the above Table 1 that using calcined crystal seeds instead of hydrolyzed seeds in the hydrolysis process can achieve a hydrolysis rate of more than 80%, and the metatitanic acid produced has a rutile titanium dioxide content of more than 94.75% after being calcined at 800°C. , which shows that the calcined seed crystal has very little loss during the entire hydrolysis process and can still play a role in subsequent calcination. It can be concluded that the method for preparing rutile titanium dioxide disclosed in the embodiment of the present invention saves the process of preparing hydrolyzed seed crystal and There is no impact on calcination when the second washing process is omitted. In addition, when calcined crystal seeds are used instead of hydrolyzed crystal seeds and the addition amount of calcined crystal seeds is increased, the hydrolysis rate reaches 94%. This hydrolysis rate is equivalent to that of conventional hydrolysis, thus ensuring the preparation of rutile disclosed in the embodiments of the present invention. Hydrolysis rate of titanium dioxide method.

In summary, the method for preparing rutile titanium dioxide disclosed in the embodiments of the present invention adds calcined seed crystals instead of hydrolyzed seed crystals into the hydrolysis process, so that the adding process of calcined seed crystals is advanced and metatitanic acid is no longer washed with water in the later stage. Adding calcined seed crystals eliminates the process of preparing hydrolyzed seed crystals, and eliminates the second washing process in the metatitanic acid water washing process. That is, only one washing is required in the metatitanic acid water washing process, thus greatly saving money. It reduces the consumption of energy and raw materials in the entire process and greatly reduces production costs.

It should be particularly pointed out that each component or step in the above-mentioned embodiments can be crossed, replaced, added, or deleted with each other. Therefore, the combination formed by these reasonable permutations, combinations, and transformations should also fall within the protection scope of the present invention and shall not be included in the protection scope of the present invention. The scope of protection of the present invention should be limited to the described embodiments.

The above are exemplary embodiments disclosed by the present invention. The order disclosed in the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. However, it should be noted that the above discussion of any embodiments is only illustrative, and is not intended to imply that the scope of the 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, it can be Make various changes and modifications. The functions, steps and/or actions of the method claims in accordance with the disclosed embodiments described herein need not be performed in any particular order. In addition, although the elements disclosed in the embodiments of the present invention may be described or claimed in individual form, they may also be understood as plural unless expressly limited to the singular.

Those of ordinary skill in the art should understand that the above discussion of any embodiments is only illustrative, and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the thinking of the embodiments of the present invention , the above embodiments or technical features in different embodiments can also be combined, and there are many other changes in different aspects of the embodiments of the present invention as described above, which are not provided in details for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention shall be included in the protection scope of the embodiments of the present invention.

Claims (5)

1. A process for preparing rutile titanium dioxide comprising the steps of:

mixing the calcined seed crystal and the hydrolyzed titanium solution;

carrying out hydrolysis; the hydrolysis comprises: heating the mixed calcined seed crystal and the hydrolyzed titanium liquid to boiling, preserving heat for 30-40 min in a boiling state, stopping heating and stirring for 30min, then opening heating and stirring to boiling, preserving heat for 3.5 hours, and ending hydrolysis, wherein the adding amount of the calcined seed crystal is 4-5.5% based on the ratio of the total titanium content of the calcined seed crystal to the total titanium content of the hydrolyzed titanium liquid, and the calcined seed crystal is a crystal with a complete rutile crystal form;

filtering and washing the hydrolyzed slurry to obtain the metatitanic acid;

and (3) carrying out salt treatment and calcination at 800 ℃ on the prepared meta-titanic acid to obtain the rutile titanium dioxide.

2. The method of producing rutile titanium dioxide according to claim 1, wherein the calcined seed and the hydrolyzed titanium liquid are mixed in such a manner that:

preheating the calcining seed crystal and the hydrolyzed titanium liquid to 60-98 ℃ respectively, and mixing; or,

preheating the calcined seed crystal to 60-98 ℃ and then mixing with the hydrolyzed titanium solution; or,

preheating the hydrolyzed titanium liquid to 60-98 ℃ and then mixing with the calcined seed crystal.

3. The method for preparing rutile titanium dioxide according to claim 1, wherein the total titanium content of the hydrolyzed titanium solution is 130-220 g/L based on the amount of titanium dioxide, the iron-titanium ratio of the hydrolyzed titanium solution is 0.15-0.45, and the F value of the hydrolyzed titanium solution is 1.50-2.10; the total titanium content of the calcined seed crystal is 80-140 g/L based on the amount of titanium dioxide.

4. The method of producing rutile titanium dioxide according to claim 1, wherein the hydrolysis is atmospheric hydrolysis or pressurized hydrolysis.

5. The method of producing rutile titanium dioxide according to claim 1, wherein the concentration of iron ions in the meta-titanic acid obtained by filtration and washing is less than 30ppm.