CN110217816A - Crude titanic chloride aluminium powder removes the aluminum removing method of vanadium mud - Google Patents

Abstract

The invention discloses a method for removing aluminum from vanadium-removing mud by crude titanium-aluminum tetrachloride powder, and belongs to the technical field of metallurgy. The present invention provides a method for removing aluminum in order to solve the technical problems of high aluminum impurity content, low aluminum impurity separation efficiency, high energy consumption, and large environmental pollution in the vanadium removal slurry of the existing crude titanium aluminum tetrachloride powder, including: Add water to the aluminum powder to remove vanadium and titanium tetrachloride mud for hydrolysis; after the hydrolysis, conduct a sedimentation and layering to obtain the supernatant and bottom thick mud; the supernatant of the first sedimentation is subjected to secondary sedimentation and layering , to obtain low-aluminum TiCl ₄ and thick mud at the bottom; the thick mud at the bottom is treated by tubular filtration or pulp evaporation according to the different solid content. The invention combines the processes of hydrolysis, primary sedimentation, secondary sedimentation, tubular filtration and pulp evaporation to separate aluminum impurities in the mud and recover titanium tetrachloride in the mud to the greatest extent.

Description

Method for removing aluminum from vanadium-removing mud by crude titanium-aluminum tetrachloride powder

technical field

The invention belongs to the technical field of metallurgy, and in particular relates to a method for removing aluminum from vanadium-removing mud by crude titanium-aluminum tetrachloride powder.

Background technique

Titanium tetrachloride (TiCl ₄ ) is an important intermediate for the production of metal titanium and its compounds. The mainstream method for industrial production of TiCl ₄ is the boiling chlorination method, but no matter whether boiling chlorination or molten salt chlorination is used, its production The obtained crude TiCl ₄ contains impurities such as AlCl ₃ , FeCl ₃ , SiCl ₄ , VOCl ₃ , VCl ₄ , etc.; the red, yellow and other abnormal colors of TiCl ₄ are caused by their existence. Generally, high boiling point components (represented by FeCl ₃ and AlCl ₃ ) and low boiling point components (represented by SiCl ₄ ) are generally removed by distillation and rectification towers. For the composition (represented by VOCl ₃ ) with a boiling point close to TiCl ₄ , when titanium tetrachloride is used to produce titanium sponge, impurity VOCl ₃ in refined titanium tetrachloride is the carrier of oxygen and vanadium that increases the hardness of titanium sponge, It is very harmful in the production of sponge titanium, and it also needs to be separated and removed. Since VOCl ₃ and TiCl ₄ have similar boiling points, separation by rectification requires a relatively large number of trays in the rectification tower, and the height of the equipment will increase accordingly, which is extremely uneconomical. Therefore, chemical methods are generally used to deal with it. Usually, a vanadium removal agent is added to crude TiCl ₄ to reduce VOCl ₃ to VOCl ₂ or precipitate or be selectively dissolved, so as to realize the separation of vanadium impurities and TiCl ₄ . At present, the common vanadium removal methods for crude titanium tetrachloride include: aluminum powder vanadium removal process, organic vanadium removal process, copper wire vanadium removal process, and hydrogen sulfide vanadium removal process, etc., but for domestic sponge titanium production enterprises, in order to ensure And to improve the quality of titanium sponge, titanium tetrachloride produced by the process of removing vanadium from aluminum powder is mostly used as the raw material for the production of titanium sponge.

The aluminum powder vanadium removal process includes one-step aluminum powder vanadium removal and two-step aluminum powder vanadium removal. The principles of the two methods are basically the same. That is, in the vanadium removal process of refined titanium aluminum tetrachloride powder, a large amount of low-valent titanium vanadium removal slurry will be added, through the reaction of VOCl ₃ (l)+TiCl ₃ (s)=VOCl ₂ (s)+TiCl ₄ (l) Vanadium removal; the preparation method of vanadium removal slurry is to add a certain amount of refined TiCl ₄ to the reaction kettle first, then add aluminum powder to the refined TiCl ₄ , and pass a certain amount of Cl ₂ to chlorinate part of the aluminum powder to form AlCl _3. Under the catalysis of AlCl ₃ , aluminum powder reacts with TiCl ₄ to form TiCl ₃ . The process reaction is:

2Al+3Cl ₂ (g)=2AlCl ₃ (1)

Al+3TiCl ₄ (l)=AlCl ₃ (l)+3TiCl ₃ (s) (2)

Therefore, when adding low-valent titanium vanadium removal slurry, a large amount of aluminum powder, AlCl ₃ and other impurities will be brought into the crude titanium refining system, which will bring great difficulties to the subsequent distillation and rectification and slurry recovery; especially for For vanadium removal mud with higher aluminum content, it will be more difficult to separate it from titanium tetrachloride in the mud, which will lead to a decrease in the operating efficiency of the entire refining system, even if part of the titanium tetrachloride in the mud is recovered and returned to refining as a raw material The process is repeated, but it will always cause some AlCl ₃ impurities to be enriched in the refining system, and then the mud must be treated for aluminum removal.

At present, CN105753042A discloses a refined hydrolysis process of crude titanium tetrachloride, which adds deliquescent NaCl to the crude _TiCl to hydrolyze titanium tetrachloride, and then settles and stratifies the hydrolyzed product to obtain the supernatant and the bottom liquid, distill and rectify the supernatant to obtain refined titanium tetrachloride, and the residue is hydrolyzed and settled again to remove AlCl ₃ , and the mud is returned to the chlorination furnace after settling; but the hydrolysis process needs to add deliquescent NaCl As a medium, the material consumption cost and operation difficulty are increased, and the processing object is mainly crude titanium tetrachloride, which is difficult to apply to complex multi-component aluminum containing VOCl ₂ , simple aluminum powder, and AlCl ₃ impurity content as high as 5% to 6%. Powder removal of vanadium slurry treatment. CN103570080B discloses a method for comprehensively recovering ferric chloride from TiCl ₄ precipitation mud. The method comprises the following steps: the TiCl ₄ precipitation mud is first separated and recovered from the TiCl ₄ by heating evaporation method or solvent leaching method, and then separated from the TiCl ₄ The obtained residue is evaporated under normal pressure or reduced pressure to recover the ferric chloride therein, or an organic solvent is added to the residue obtained after separating TiCl ₄ , and the ferric chloride is selectively leached and then filtered, and the filtrate is distilled under normal pressure or reduced pressure Separate organic solvent and ferric chloride. CN102009999B discloses a method in which solid-containing mud produced at the bottom of a settling tank is gasified to recover titanium tetrachloride, and solid impurities are dried into slag and put into a vanadium slag tank. Therefore, a technical means that can effectively solve the excessively high aluminum content in the vanadium removal slurry of crude titanium aluminum tetrachloride powder has not been developed yet.

Contents of the invention

The invention aims to solve the technical problems of high aluminum impurity content in the vanadium removal slurry of the existing crude titanium tetrachloride aluminum powder, low separation efficiency of titanium tetrachloride and aluminum impurities, high energy consumption, and large environmental pollution.

The technical scheme adopted by the present invention to solve the problems of the technologies described above is to provide a method for removing aluminum from the vanadium-removing slurry of thick titanium-aluminum tetrachloride powder, the method comprising the following steps:

A. Add water to the aluminum powder to remove vanadium and titanium tetrachloride slurry for hydrolysis;

B. After the hydrolysis is finished, carry out a settling and layering to obtain the supernatant and the thick mud a at the bottom;

C, the supernatant of the primary sedimentation is subjected to secondary sedimentation, and layered to obtain low-aluminum TiCl ₄ and thick mud b at the bottom;

D. According to the difference in solid content of the bottom thick mud a and b, select tubular filtration or pulp evaporation to recover TiCl ₄ .

Wherein, in the method for removing aluminum from vanadium-removing slurry with crude titanium-aluminum tetrachloride powder, in step A, the mass content of AlCl3 impurities in the aluminum powder-removing vanadium-titanium tetrachloride slurry is ₃ %-6%.

Preferably, in the method for removing aluminum from vanadium-removing slurry with crude titanium-aluminum tetrachloride powder, in step A, the mass content _of AlCl3 in the aluminum powder-removing vanadium-titanium tetrachloride slurry is 5% to 6%.

Wherein, in the method for removing aluminum from vanadium-removing slurry with crude titanium-aluminum tetrachloride powder, in step A, the amount of water added is 0.2%-0.25% of the mass of aluminum powder-removing vanadium-titanium tetrachloride slurry.

Wherein, in the method for removing aluminum from the vanadium-removing slurry of the crude titanium-aluminum tetrachloride powder, in step A, the hydrolysis time is 55-65 minutes.

Wherein, in the method for removing aluminum from the vanadium-removing slurry of the crude titanium-aluminum tetrachloride powder, in step B, the time for the primary settlement is 18-24 hours.

Wherein, in the method for removing aluminum from the vanadium-removing slurry of the crude titanium-aluminum tetrachloride powder, in step C, the time for the secondary settlement is 8-12 hours.

Wherein, in the method for removing aluminum from the vanadium-removing slurry of the crude titanium _- aluminum tetrachloride powder, the AlCl3 impurity mass content in the supernatant obtained from the primary sedimentation is 0.20% to 0.50%, and the solid content is 120g/L to 180g/L .

Wherein, in the method for removing aluminum from the vanadium-removing slurry of the crude titanium-aluminum tetrachloride powder, the mass content of AlCl3 impurities in the low _- aluminum _TiCl4 obtained by secondary sedimentation is ≤0.050%, and the solid content is ≤50g/L.

Wherein, in the aluminum removal method of the described crude titanium aluminum tetrachloride powder removal vanadium slurry, the concrete operation of step D is:

When the solid content of bottom thick mud a, bottom thick mud b or mixture of a and b is less than or equal to 300g/ _L , perform tubular filtration to remove AlCl Impurities and recover titanium tetrachloride;

When the solid content of the bottom thick mud a, bottom thick mud b or the mixture of a and b is >300g/L, the slurry is evaporated at a temperature of 250-450°C, and slaked lime is added to convert the AlCl ₃ impurity into Al ₂ O ₃ into the containing Aluminum dry residue, titanium tetrachloride volatilized during the evaporation process is collected through condensation and returned to the secondary settling tank for settling recovery.

According to the aluminum removal method of thick titanium aluminum tetrachloride powder removal vanadium mud that the present invention provides, the present invention has also designed a kind of equipment applicable to this method, and it comprises following structure: aluminum powder vanadium removal mud tank (1), hydrolysis Tank (2), Primary Settling Tank (3), Secondary Settling Tank (4), Tube Filter (5), Slurry Evaporator (6) and Low Aluminum TiCl ₄ Storage Tank (7).

Beneficial effects of the present invention:

The present invention can stably and efficiently treat the vanadium-removing slurry of aluminum powder containing relatively high aluminum impurities through the process of hydrolysis-primary sedimentation-secondary sedimentation-tubular filtration-sedimentation and evaporation of mud and pulp after tubular filtration, and is especially suitable for AlCl ₃ The content is as high as 5% to 6% in the mud, and the aluminum impurities such as aluminum powder, AlOCl, AlCl ₃ and TiCl ₄ in the mud can be efficiently separated in a short time, and the titanium recovery rate can reach more than 98%. The operation is simple and the energy consumption is low.

Description of drawings

Fig. 1 is the process schematic diagram of the thick titanium aluminum chloride powder vanadium removal mud of the present invention except aluminum, wherein, 1-aluminum powder removes vanadium mud tank, 2-hydrolysis tank, 3-primary settling tank, 4-secondary settling tank , 5-pipe filter, 6-slurry evaporation furnace, 7-low aluminum TiCl ₄ storage tank.

Detailed ways

Concrete, the aluminum removal method of crude titanium aluminum tetrachloride powder removal vanadium mud, this method comprises the following steps:

A. Add water to the aluminum powder to remove vanadium and titanium tetrachloride slurry for hydrolysis;

B. After the hydrolysis is finished, carry out a settling and layering to obtain the supernatant and the thick mud a at the bottom;

C, the supernatant of the primary sedimentation is subjected to secondary sedimentation, and layered to obtain low-aluminum TiCl ₄ and thick mud b at the bottom;

D. According to the difference in solid content of the bottom thick mud a and b, select tubular filtration or pulp evaporation to recover TiCl ₄ .

Among the present invention, thick titanium aluminum tetrachloride powder vanadium removal mud is derived from the bottom row residue that thick titanium aluminum tetrachloride powder removes vanadium reaction to produce, and it still contains a large amount of titanium tetrachloride, but because its AlCl _The impurity mass content reaches 3% to 6%, it is difficult to apply directly, so it needs to remove aluminum. Due to the complex composition of the mud and the high content of AlCl ₃ impurities, the effect of removing aluminum is not good if it is directly treated by tubular filtration or slurry evaporation. Therefore, the present invention develops an aluminum removal method for crude titanium aluminum tetrachloride powder to remove vanadium mud, and the method is especially suitable for 5%-6% mud.

In the hydrolysis process of step A of the present invention, the amount of water added is 0.2% to 0.25% of the mass of the aluminum powder-removed vanadium _- titanium tetrachloride mud, so as to fully hydrolyze and precipitate AlCl3 in the mud. However, water reacts violently with AlCl ₃ , so the present invention uses a hydraulic injector to realize sufficient contact reaction between water and crude titanium tetrachloride containing AlCl ₃ under dynamic conditions, while avoiding severe local reactions.

The invention controls the amount of water and the way of adding water, and has high hydrolysis reaction efficiency, so the hydrolysis time only needs 55-65 minutes.

After the hydrolysis reaction, due to the high content of solid impurities in the system, it takes a long time to settling, so in step B, the time for one settling is controlled to be 18-24h. The AlCl ₃ impurity mass content in the supernatant obtained through one settling is 0.20%-0.50%, and the solid content is 120g/L-180g/L.

In order to further improve the purity of titanium tetrachloride, in step C, the secondary sedimentation is carried out for 8-12 hours, and the AlCl3 impurity mass content in the low _- aluminum TiCl obtained from the secondary sedimentation is ≤0.050%, and the solid content is ≤50g/L. The low-aluminum _{TiCl 4} It has met the production quality requirements and can be used as a raw material in the refining system.

A large amount of TiCl ₄ still remains in the bottom thick mud a and bottom thick mud b, so further treatment is required. Bottom thick mud a and bottom thick mud b can be processed directly or mixed according to the actual processing capacity of the production organization. When the solid content of the bottom thick mud a, the bottom thick mud b or the mixture of a and b is less than or equal to 300g/L, perform tubular filtration to remove the AlCl ₃ impurities, and reclaim titanium tetrachloride; when the bottom thick mud a, the bottom thick mud b or When the solid content of the mixture of a and b is more than 300g/L, it is easy to cause the filter cloth of the tubular filter to fail, so the pulp is evaporated at a temperature of 250-450°C, and slaked lime is added to convert the AlCl ₃ impurity into Al ₂ O ₃ Enter the aluminum-containing dry slag, and the titanium tetrachloride obtained by volatilization during the evaporation process is collected by condensation and returned to the secondary settling tank for settlement recovery.

According to the aluminum removal method of thick titanium aluminum tetrachloride powder removal vanadium mud that the present invention provides, the present invention has also designed a kind of equipment applicable to this method, and it comprises following structure: aluminum powder vanadium removal mud tank (1), hydrolysis Tank (2), Primary Settling Tank (3), Secondary Settling Tank (4), Tube Filter (5), Slurry Evaporator (6) and Low Aluminum TiCl ₄ Storage Tank (7).

In the present invention, the said content is the mass percentage content.

The present invention will be further described in detail through the examples below, but the protection scope of the present invention is not limited to the scope of the examples.

Example 1

The titanium tetrachloride slurry containing AlCl ₃ with an impurity content of 3.58% was hydrolyzed. The main composition of the material before hydrolysis was TiCl ₄ , and the impurity compositions were: FeCl ₃ was 0.21%, AlCl ₃ was 3.58%, VOCl ₂ was 1.28%, TiCl ₃ is 1.2%, and its solid content is 134g/L; the total amount of hydrolyzed materials in the hydrolysis tank is 19.5t, the controlled water addition is 40kg, and the hydrolysis time is 60min. The negative pressure generated by the medium flow is automatically sucked into the hydrolysis tank, and the material after hydrolysis is directly discharged to the primary settling tank for settlement. The settling tank equipment is a thickener, and the settling time is set at 18 hours. Clear liquid (accounting for the total material 3/4 of settlement) is discharged into the secondary settling tank and continues to settle for 8h. The upper clear liquid after the secondary settlement is sampled and analyzed to establish the impurity _AlCl content in the clear liquid titanium tetrachloride. The results are shown in Table 1.

Impurity composition before and after sedimentation in Table 1 Example 1

FeCl₃/% AlCl₃/% VOCl₂/% TiCl₃/% Solid content/g.L^-1 Hydrolyzed material 0.21 3.58 1.28 1.20 134 18 hours after a settlement 0.076 0.985 0.186 0.020 75 After 8 hours of secondary sedimentation 0.009 0.015 0.010 0.008 36

The solid content of the thick mud at the bottom of the primary settlement and the secondary settlement is ≤300g/L, and the tubular filtration is carried out. The content of AlCl ₃ in the filtered titanium tetrachloride is reduced to 0.0049%, and the content of other main impurities is FeCl ₃ -0.0186%, SiCl ₄ -0.0073%, VOCl ₃ -0.0391%; after tubular filtration and secondary sedimentation, the aluminum impurities in the clear liquid are greatly reduced, and the content of other impurities also meets the quality requirements for the reuse of crude titanium tetrachloride. The overall titanium recovery rate is 98%.

Example 2

The titanium tetrachloride mud containing AlCl ₃ with an impurity content of 5.48% was hydrolyzed. The main composition was TiCl ₄ , and the impurity compositions were: 0.36% FeCl ₃ , 5.48% AlCl ₃ , 1.76% VOCl ₂ , TiCl ₃ It is 1.54%, and its solid content is 230g/L; the total amount of double hydrolyzed materials in the hydrolysis tank is 20t, the controlled water addition is 45kg, and the hydrolysis time is 60min. After hydrolysis, the settling time of the primary settling tank is 20h. After 20h, the upper clear liquid of the primary settling tank is discharged into the secondary settling tank to continue to settle for 12h, and the upper clear liquid after the first and second settling is sampled and analyzed to establish the impurity _AlCl content in the clear liquid titanium tetrachloride. The results are shown in Table 2.

Impurity composition before and after sedimentation in Table 2 Example 2

FeCl₃/% AlCl₃/% VOCl₂/% TiCl₃/% Solid content/g.L^-1 Hydrolyzed material 0.36 5.48 1.76 1.54 230 18 hours after a settlement 0.096 1.256 0.179 0.024 80 After 8 hours of secondary sedimentation 0.008 0.016 0.010 0.009 25

After secondary sedimentation, aluminum impurities in the supernatant can be reduced from 5.48% to 0.016%. Mix the thick mud at the bottom of the primary sedimentation with the secondary sedimentation, its solid content > 300g/L, and directly enter the slurry evaporation furnace for evaporation. After evaporation and condensation, the content of AlCl ₃ in titanium tetrachloride is 0.0390%, and return it to the secondary sedimentation Settling again in the tank; after the pulp is evaporated, the composition of the dry residue is Ti ₂ O ₃ -13.3%, TiO ₂ -3.1%, VO ₂ -8.4%, Al ₂ O ₃ -33.1%, CaCl ₂ -36.7%, and the remaining solid The total content of phase matter is 5.4%, and the recovery rate of overall titanium is 96.8%.

Claims (10)

1. the aluminum removal method of thick titanium aluminum tetrachloride powder removal vanadium mud, it is characterized in that: comprise the following steps: A. Add water to the aluminum powder to remove vanadium and titanium tetrachloride slurry for hydrolysis; B. After the hydrolysis is finished, carry out a settling and layering to obtain the supernatant and the thick mud a at the bottom; C, the supernatant of the primary sedimentation is subjected to secondary sedimentation, and layered to obtain low-aluminum TiCl ₄ and thick mud b at the bottom; D. According to the difference in solid content of the bottom thick mud a and b, select tubular filtration or pulp evaporation to recover TiCl ₄ . 2. the aluminum removal method of thick titanium aluminum tetrachloride powder according to claim 1 except vanadium tetrachloride mud, it is characterized in that: in step _A , described aluminum powder is removed in the vanadium titanium tetrachloride mud AlCl Impurity mass content is 3% to 6%; preferably 5 to 6%. 3. the aluminum removal method of thick titanium aluminum tetrachloride powder de-vanadium tetrachloride mud according to claim 1, it is characterized in that: in step A, the add-on of described water is aluminum powder de-vanadium titanium tetrachloride mud quality 0.2% to 0.25%. 4. The method for removing aluminum from vanadium-removing slurry of crude titanium-aluminum tetrachloride powder according to claim 1, characterized in that in step A, the hydrolysis time is 55 minutes to 65 minutes. 5. The method for removing aluminum from vanadium-removing slurry of crude titanium-aluminum tetrachloride powder according to claim 1, characterized in that: in step B, the time for the primary settlement is 18-24 hours. 6 . The method for removing aluminum from vanadium-removing slurry of crude titanium aluminum tetrachloride powder according to claim 1 , characterized in that in step C, the time for the secondary settlement is 8 to 12 hours. 7. The method for removing aluminum from the vanadium-removing slurry of crude titanium-aluminum tetrachloride powder according to any one of claims 1 to ₆ , characterized in that: the AlCl3 impurity mass content in the supernatant obtained from one settling is 0.20% to 0.50% %, the solid content is 120g/L～180g/L. 8. The method for removing aluminum from the vanadium-removing slurry of crude titanium-aluminum tetrachloride powder according to any one of claims 1 to 6, characterized in that: the mass content of AlCl ₃ impurities in the low-aluminum TiCl ₄ obtained by secondary sedimentation is ≤0.050% , solid content ≤ 50g/L. 9. the aluminum removal method of thick titanium aluminum tetrachloride powder removal vanadium mud according to claim 1, it is characterized in that: the concrete operation of step D is: When the solid content of bottom thick mud a, bottom thick mud b or mixture of a and b is less than or equal to 300g/ _L , perform tubular filtration to remove AlCl Impurities and recover titanium tetrachloride; When the solid content of the bottom thick mud a, bottom thick mud b or the mixture of a and b is >300g/L, the slurry is evaporated at a temperature of 250-450°C, and slaked lime is added to convert the AlCl ₃ impurity into Al ₂ O ₃ into the containing Aluminum dry residue, titanium tetrachloride volatilized during the evaporation process is collected through condensation and returned to the secondary settling tank for settling recovery. 10. according to the aluminum removal method of thick titanium aluminum tetrachloride powder vanadium removal mud described in any one of claim 1～9, it is characterized in that: the equipment that this method adopts comprises following structure: aluminum powder vanadium removal mud tank ( 1), hydrolysis tank (2), primary settling tank (3), secondary settling tank (4), tubular filter (5), slurry evaporation furnace (6) and low aluminum TiCl ₄ storage tank (7).