CN117923893A - A method for preparing aluminum titanate ceramics - Google Patents

Abstract

The present invention belongs to the technical field of solid waste recycling, and specifically relates to a method for preparing aluminum titanate ceramics. The present invention provides a method for preparing aluminum titanate ceramics, comprising the following steps: mixing vanadium-titanium-based waste selective catalytic reduction catalyst and alumina, pressing and sintering in sequence, to obtain the aluminum titanate ceramics. The preparation method provided by the present invention uses vanadium-titanium-based waste selective catalytic reduction (SCR) catalyst as raw material, and presses and sinters it with alumina powder, so that the waste SCR catalyst and alumina are subjected to high temperature and pressure at the same time, and thermal energy and stress are used to promote the bonding of powder particles and the densification of materials, and the obtained aluminum titanate ceramics have high purity. Different from the existing wet recovery process in which waste SCR catalysts are recovered in the form of metal compounds, the method provided by the present invention realizes the high added value utilization of waste SCR catalysts, and the process is simple, safe and environmentally friendly.

Description

A method for preparing aluminum titanate ceramics

Technical Field

The invention belongs to the technical field of solid waste recycling, and specifically relates to a method for preparing aluminum titanate ceramics.

Background technique

Vanadium-titanium-based selective catalytic reduction (SCR) catalysts are mainly used in flue gas denitration treatment processes. During use, the active components or microstructures of such catalysts will change due to the influence of the working environment, which will reduce their denitration performance and even cause them to lose activity in severe cases. The composition and content of the vanadium-titanium-based SCR catalysts will vary depending on the location where they are used, but the main substance is titanium dioxide, which accounts for more than 80%, and has high recycling value.

At present, the recycling of inactive waste SCR catalysts mainly involves extracting precious metals through acid dissolution, alkali dissolution, salt dissolution, etc., or reducing the metal elements into metal elements or alloys through high-temperature smelting. However, due to the complex composition of waste SCR catalysts, waste SCR catalysts of different types and origins may have different properties and components, so different treatment methods and processes are required, and the recycling rate is low.

Summary of the invention

The purpose of the present invention is to provide a method for preparing aluminum titanate ceramics. The method provided by the present invention can achieve efficient resource utilization of vanadium-titanium-based waste selective catalytic reduction catalysts and prepare aluminum titanate ceramics with higher purity.

In order to achieve the above object, the present invention provides the following technical solutions:

The present invention provides a method for preparing aluminum titanate ceramics, comprising the following steps:

The aluminum titanate ceramic is obtained by mixing the vanadium-titanium-based waste selective catalytic reduction catalyst and alumina, pressing and sintering them in sequence.

Preferably, the mass percentage of titanium dioxide in the vanadium-titanium-based spent selective catalytic reduction catalyst is 70-100%.

Preferably, the mass ratio of the vanadium-titanium based waste selective catalytic reduction catalyst to alumina is 9:10-15.

Preferably, the mixing is performed by ball milling; the rotation speed of the ball milling is 200-600 r/min, and the time is 4-16 h.

Preferably, the ball milling is wet milling; and the dispersant of the wet milling is alcohol.

Preferably, the pressing pressure is 8-12 MPa, and the holding time is 1-3 min.

Preferably, the sintering temperature is 1300-1600° C., and the holding time is 2-6 hours.

Preferably, before the mixing, the vanadium-titanium based waste selective catalytic reduction catalyst is sequentially washed, dried, crushed and sieved.

Preferably, the cleaning is ultrasonic cleaning; the time of the ultrasonic cleaning is 8 to 16 hours;

The drying is oven drying; the oven drying temperature is 60-120° C. and the drying time is 12-36 hours.

Preferably, the mesh size of the sieve is 200-600 meshes.

The present invention provides a method for preparing aluminum titanate ceramics, comprising the following steps: mixing vanadium-titanium-based waste selective catalytic reduction catalyst and alumina, and pressing and sintering them in sequence to obtain the aluminum titanate ceramics. The preparation method provided by the present invention uses vanadium-titanium-based waste selective catalytic reduction (SCR) catalyst as raw material, and presses and sinters it with alumina powder, so that the waste SCR catalyst and alumina are subjected to high temperature and pressure at the same time, and uses thermal energy and stress to promote the bonding of powder particles and the densification of materials, and the obtained aluminum titanate ceramics have high purity. Different from the existing wet recovery process in which waste SCR catalysts are recovered in the form of metal compounds, the method provided by the present invention realizes the high added value utilization of waste SCR catalysts and the harmlessness and resource utilization of solid wastes, and the process is simple. During the recycling process, no polluting waste liquid or gas is generated, which is safe and environmentally friendly.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

FIG1 is a comparison diagram of the X-ray diffraction spectrum of the aluminum titanate ceramic obtained in Example 1 (upper) and the standard XRD spectrum of aluminum titanate (lower);

FIG2 is a comparison diagram of the X-ray diffraction spectrum of the aluminum titanate ceramic obtained in Example 2 (top) and the standard XRD spectrum of aluminum titanate (bottom).

Detailed ways

The present invention provides a method for preparing aluminum titanate ceramics, comprising the following steps:

The aluminum titanate ceramic is obtained by mixing the vanadium-titanium-based waste selective catalytic reduction catalyst and alumina, pressing and sintering them in sequence.

In the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art.

In the present invention, the mass percentage of titanium dioxide in the vanadium-titanium-based waste selective catalytic reduction catalyst is preferably 70-100%, more preferably 80-90%, and most preferably 86.29%; the mass percentage of tungsten oxide is preferably 0-10%, more preferably 2-8%, and most preferably 5.24%; the mass percentage of calcium oxide is preferably 0-3%, more preferably 1-2%, and most preferably 1.40%; the mass percentage of silicon oxide is preferably 0-10%, more preferably 2-8%, and most preferably 4.34%; the mass percentage of vanadium pentoxide is preferably 0-5%, more preferably 0.5-3%, and most preferably 0.69%.

In the present invention, the step of washing, drying, crushing and sieving the vanadium-titanium based waste selective catalytic reduction catalyst in sequence before the mixing.

In the present invention, the cleaning is preferably ultrasonic cleaning; the time of the ultrasonic cleaning is preferably 8 to 16 hours, more preferably 10 to 14 hours; the ultrasonic cleaning is preferably carried out in an ultrasonic cleaning instrument; the cleaning serves to remove ash and a large amount of dust from the waste SCR catalyst.

In the present invention, the drying is preferably oven drying; the oven drying temperature is preferably 60-120° C., more preferably 80-100° C.; the oven drying time is preferably 12-36 h, more preferably 18-30 h.

In the present invention, the mesh size of the sieve is preferably 200-600 meshes, more preferably 300-500 meshes.

In the present invention, the mass ratio of the vanadium-titanium-based spent selective catalytic reduction catalyst to alumina is preferably 9:10-15, more preferably 9:10-13, and most preferably 9:10-11.

In the present invention, the mixing is ball milling; the rotation speed of the ball mill is preferably 200-600 r/min, more preferably 300-500 r/min; the time is preferably 4-16 h, more preferably 8-12 h; the ball milling is preferably wet milling; the dispersant for wet milling is preferably alcohol; the present invention does not have any special limitation on the amount of the alcohol, and the amount of ball milling dispersant well known to those skilled in the art can be used to immerse the ball milling raw materials.

In the present invention, the ball milling is preferably followed by drying; the drying temperature is preferably 60-120° C., more preferably 80-100° C.; the drying time is preferably 12-36 h, more preferably 18-30 h.

In the present invention, the pressing pressure is preferably 8-12 MPa, more preferably 9-11 MPa; the holding time is preferably 1-3 min, more preferably 2-3 min.

In the present invention, the sintering temperature is preferably 1300-1600° C., more preferably 1400-1500° C.; the holding time is preferably 2-6 hours, more preferably 3-5 hours.

The preparation method provided by the present invention uses vanadium-titanium-based waste selective catalytic reduction (SCR) catalyst as raw material, and presses and sinters it with alumina powder, so that the waste SCR catalyst and alumina are subjected to high temperature and pressure at the same time, and thermal energy and stress are used to promote the bonding of powder particles and the densification of materials, and the obtained aluminum titanate ceramic has a high purity. Different from the existing wet recovery process in which waste SCR catalysts are recovered in the form of metal compounds, the method provided by the present invention realizes the high added value utilization of waste SCR catalysts and the harmlessness and resource utilization of solid waste, and the process is simple. During the recycling process, no polluting waste liquid or gas is generated, which is safe and environmentally friendly. The main chemical reaction formula in the preparation method described in the present invention is Formula 1:

TiO ₂ +Al ₂ O ₃ =Al ₂ TiO ₅ (Formula 1).

In order to further illustrate the present invention, the preparation method of the aluminum titanate ceramic provided by the present invention is described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the protection scope of the present invention.

Example 1

The bulk vanadium-titanium-based waste SCR catalyst is placed in distilled water and ultrasonically cleaned in an ultrasonic cleaner for 12 hours. The waste SCR catalyst is taken out and dried in an 80°C drying oven for 24 hours, and then the waste SCR catalyst is crushed and passed through a 400-mesh sieve to obtain a crushed waste SCR catalyst. The mass percentage of titanium dioxide in the vanadium-titanium-based waste selective catalytic reduction catalyst is 86.29%, the mass percentage of tungsten oxide is 5.24%, the mass percentage of calcium oxide is 1.40%, the mass percentage of silicon oxide is 4.34%, and the mass percentage of vanadium pentoxide is 0.69%.

Weigh 9.25g of waste SCR catalyst and 10.2g of alumina, put them into a ball mill, add alcohol to make the alcohol just submerge the powder, and perform mechanical ball milling at a speed of 300r/min for 12h. Put the evenly mixed waste SCR catalyst and alumina into an evaporating dish and bake them in an 80℃ drying oven for 24h. Finally, take out the dried, evenly mixed waste SCR catalyst and alumina and press them into tablets.

1 g of the uniformly mixed waste SCR catalyst and alumina was weighed and put into a circular mold with a diameter of 8 mm for tableting at a pressure of 10 MPa for 2.5 min.

The pressed sheet is placed in a crucible, and the crucible is placed in a high-temperature furnace, heated to 1500°C, and kept at 1500°C for 4 hours. After the insulation is completed, the furnace is cooled to room temperature, and the sintered sheet is taken out to obtain aluminum titanate ceramics.

The X-ray diffraction spectrum (upper) and the standard XRD spectrum (lower) of the aluminum titanate ceramic obtained in this embodiment are shown in FIG. 1 . As can be seen from FIG. 1 , the main phase of the obtained aluminum titanate ceramic is aluminum titanate, the content of other impurity phases is low, and the product purity is relatively high.

Example 2

The bulk vanadium-titanium-based waste SCR catalyst was placed in distilled water and ultrasonically cleaned in an ultrasonic cleaner for 12 hours. The waste SCR catalyst was taken out and dried in a drying oven at 80°C for 24 hours, and then the waste SCR catalyst was crushed and passed through a 400-mesh sieve to obtain a crushed waste SCR catalyst.

Weigh 9.25g of waste SCR catalyst and 11.22g of alumina, put them into a ball mill, add alcohol to make the alcohol just submerge the powder, and perform mechanical ball milling at a speed of 300r/min for 12h. Put the evenly mixed waste SCR catalyst and alumina into an evaporating dish and bake them in an 80℃ drying oven for 24h. Finally, take out the dried, evenly mixed waste SCR catalyst and alumina and press them into tablets.

1 g of the uniformly mixed waste SCR catalyst and alumina was weighed and put into a circular mold with a diameter of 8 mm for tableting at a pressure of 10 MPa for 2.5 min.

The pressed sheet is placed in a crucible, and the crucible is placed in a high-temperature furnace, heated to 1500°C, and kept at 1500°C for 4 hours. After the insulation is completed, the furnace is cooled to room temperature, and the sintered sheet is taken out to obtain aluminum titanate ceramics.

The X-ray diffraction pattern (above) and the standard XRD pattern (below) of the aluminum titanate ceramic obtained in this embodiment are shown in FIG. 2 . It can be seen from the XRD pattern that the main phase of the aluminum titanate ceramic obtained is aluminum titanate, the content of other impurity phases is low, and the product purity is relatively high.

Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims (10)

1. The preparation method of the aluminum titanate ceramic is characterized by comprising the following steps of:

mixing the vanadium-titanium-based waste selective catalytic reduction catalyst with alumina, and sequentially pressing and sintering to obtain the aluminum titanate ceramic.

2. The preparation method of claim 1, wherein the mass percentage of titanium dioxide in the vanadium-titanium-based spent selective catalytic reduction catalyst is 70-100%.

3. The preparation method according to claim 1 or 2, wherein the mass ratio of the vanadium-titanium-based spent selective catalytic reduction catalyst to alumina is 9: 10-15.

4. The method of claim 1, wherein the mixing is ball milling; the rotation speed of the ball milling is 200-600 r/min, and the time is 4-16 h.

5. The method of claim 4, wherein the ball milling is wet milling; the dispersant for wet milling is alcohol.

6. The method according to claim 1, wherein the pressing pressure is 8-12 mpa and the dwell time is 1-3 min.

7. The preparation method according to claim 1, wherein the sintering temperature is 1300-1600 ℃ and the heat preservation time is 2-6 h.

8. The method according to claim 1 or 4, wherein the mixing is preceded by washing, drying, pulverizing and sieving the vanadium-titanium-based spent selective catalytic reduction catalyst in that order.

9. The method of claim 8, wherein the cleaning is ultrasonic cleaning; the ultrasonic cleaning time is 8-16 hours;

The drying is drying; the temperature of the drying is 60-120 ℃ and the time is 12-36 h.

10. The method of claim 8, wherein the screened mesh number is 200-600 mesh.