WO2024037242A1 - Method for preparing ethylene oxide catalyst carrier by using waste catalyst - Google Patents

Abstract

A method for preparing an ethylene oxide catalyst carrier by using a waste catalyst, comprising: drying alumina recovered from a waste catalyst, and grinding same to 5-100 μm; mixing 0.5-3.5 parts by weight of alumina, 1-4 parts by weight of gibbsite, and 1-4 parts by weight of AlO(OH) as a raw material, adding an auxiliary agent, and carrying out compression molding to obtain a carrier precursor; and carrying out high-temperature roasting and shaping on the carrier precursor at 1,200-1,500°C to obtain an α-alumina porous carrier. The α-alumina porous carrier has a large water absorption rate, high compression resistance, and large pore volume, and can be further used for preparing ethylene oxide catalysts having excellent catalytic activity. According to the method, waste catalysts are utilized, natural resources are saved, and production costs are reduced; moreover, the problem of environmental pollution caused by inappropriate storage of residual alumina after recovering precious metals from waste catalysts can also be avoided.

Description

A method for preparing ethylene oxide catalyst carrier using waste catalyst Technical field

The invention belongs to the technical field of catalysts, and specifically relates to a method for preparing an ethylene oxide catalyst carrier by utilizing waste catalyst.

Background technique

Precious metal catalysts such as platinum, palladium and silver will gradually become deactivated with use, and the catalyst will no longer play a corresponding role. At this time, the precious metals in the spent catalyst need to be recovered. After precious metals are recovered, a large amount of alumina with higher purity will be obtained. Although the economic value of this part of alumina is very low compared to the recycled precious metals, if this part of alumina is not properly stored, it will cause serious environmental problems. The current conventional utilization method is to use it as a refractory material. However, due to the high purity of this part of alumina, it is undoubtedly wasted as a refractory material.

Ethylene oxide is an important chemical intermediate that can further produce major consumer chemical products required on the market, such as antifreeze, pharmaceuticals, detergents, plastics and dozens of other fine chemical products. At present, the industrial production of ethylene oxide is mainly based on the direct reaction of ethylene and oxygen under a silver catalyst. The key technology of this process is the use of Ag/Al ₂ O ₃ catalyst, which can significantly improve the production efficiency of ethylene oxide. In view of this, this application proposes a method for reusing the alumina in the spent catalyst as the raw material for the ethylene oxide catalyst carrier.

Contents of the invention

The object of the present invention is to provide a method for preparing an ethylene oxide catalyst carrier by using a waste catalyst to further improve the utilization efficiency of alumina in the waste catalyst and save natural resources and production costs. At the same time, environmental pollution is reduced.

The present invention is realized through the following technical solutions:

A method for preparing ethylene oxide catalyst carrier using spent catalyst, which includes:

After drying the alumina recovered from the spent catalyst, grind it to 5-100 μm;

Mix 0.5-3.5 parts by weight of alumina, 1-4 parts by weight of gibbsite and 1-4 parts by weight of gibbsite as raw materials. After adding additives and binders, press and shape to obtain a carrier precursor. ;as well as

The carrier precursor is calcined at high temperature at 1200 to 1500°C to obtain a porous carrier of α-alumina.

Further, in a preferred embodiment of the present invention, the temperature at which the recovered alumina is dried is 80 to 200°C.

Further, in a preferred embodiment of the present invention, the spent catalyst includes at least one of a deactivated platinum-containing catalyst, a palladium-containing catalyst, and a silver-containing catalyst.

Furthermore, in a preferred embodiment of the present invention, before drying the alumina, it also includes the step of passing the recovered alumina through a 20-40 mesh sieve to remove impurities.

Further, in a preferred embodiment of the present invention, the auxiliary agent includes carbon material, magnesium source and fluoride;

The added amount of carbon material is 5-20% of the raw material; the added amount of magnesium source is 0.1-1.5% of the raw material; the added amount of fluoride is 0.1-2% of the raw material.

Further, in a preferred embodiment of the present invention, the carbon material includes at least one of activated carbon powder, petroleum coke powder, graphite, polyethylene, and polypropylene.

Further, in a preferred embodiment of the present invention, the magnesium source includes at least one of magnesium oxide, magnesium acetate and magnesium carbonate.

Further, in a preferred embodiment of the present invention, the fluoride includes ammonium fluoride and/or aluminum fluoride.

Furthermore, in a preferred embodiment of the present invention, the binder is nitric acid.

Further, in a preferred embodiment of the present invention, the characteristics of the porous carrier of α-alumina are: specific surface ≤ 3㎡/g, water absorption ≥ 40%, compressive strength ≥ 100N/piece, pore volume ≥ 0.20 .

Compared with the prior art, the present invention at least has the following technical effects:

This method uses alumina recovered from spent catalysts as the basic raw material. After drying and grinding it, it is mixed with gibbsite, monohydrate and additives. After pressing and molding, carriers such as rings, porous columns, and cylinders are obtained. Precursor. The carrier precursor is then calcined at high temperature to form a porous carrier of α-alumina.

This α-alumina porous carrier has high water absorption, strong pressure resistance, and large pore volume, and can be further used to prepare ethylene oxide catalysts with excellent catalytic activity. Therefore, this method not only utilizes the spent catalyst, but also saves natural resources and production costs. It can also avoid environmental pollution problems caused by poor storage of the remaining alumina after recovering precious metals from the spent catalyst.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. There is no indication in the examples. The specific conditions should be carried out in accordance with conventional conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated on the reagents or instruments used, they are conventional products that can be purchased commercially.

The technical solution of the present invention is:

This embodiment provides a method for preparing an ethylene oxide catalyst carrier using spent catalyst, which includes the following steps:

Step S1, process the recovered alumina: After drying the alumina recovered from the spent catalyst, grind it to 5~100μm.

The spent catalyst includes at least one of a deactivated platinum-containing catalyst, a palladium-containing catalyst, and a silver-containing catalyst. This type of spent catalyst contains the precious metals platinum, palladium and silver, and contains higher purity alumina. When the precious metals (platinum, palladium and silver) in such spent catalysts are recovered, a large amount of alumina with higher purity will be obtained. Among them, the alumina content in the platinum-containing catalyst or palladium-containing catalyst is >99wt%, and the alumina content in the silver-containing catalyst is >80wt%.

In this step, the dry alumina is ground to 5 to 100 μm, preferably 20 to 60 μm. The inventor found through research that the particle size of alumina will affect the pore volume of the prepared catalyst carrier. When the particle size of alumina is less than 5 μm, the pore volume will be greatly reduced; when the particle size of alumina is greater than 100 μm, the carrier strength will be reduced.

Further, in this step, the recovered alumina is dried at a temperature of 80 to 200°C (preferably 100 to 180°C, more preferably 120 to 150°C). Drying within this temperature range can produce Helps balance drying speed and energy consumption

Further, before drying the alumina, it also includes the step of passing the recovered alumina through a 20-40 mesh sieve to remove alumina with larger particle sizes and impurities to facilitate processing in subsequent steps.

Step S2, prepare carrier precursor:

Mix 0.5-3.5 parts by weight of alumina, 1-4 parts by weight of gibbsite and 1-4 parts by weight of gibbsite as raw materials, add additives and binders, and shape to obtain a carrier precursor.

Among them, the chemical formula of gibbsite is Al(OH) ₃ and its chemical composition: Al ₂ O ₃ 65.4%, H ₂ O 34.6%. The structural formula of monohydrate is AlO(OH) and the molecular formula is Al ₂ O ₃ ·H ₂ O.

Further, the auxiliary agent includes carbon material, magnesium source and fluoride, and the binder is nitric acid solution.

Wherein, the added amount of carbon material is 5-20% of the raw material (preferably, the added amount of carbon material is 8-15% of the raw materials). The addition of carbon material mainly plays a lubrication role and is beneficial to pore creation during the later roasting process. The carbon material includes at least one of activated carbon powder, petroleum coke powder, graphite, polyethylene, and polypropylene. Preferably, the carbon material is activated carbon powder or graphite.

The added amount of the magnesium source is 0.1 to 1.5% of the raw material, and the magnesium source includes at least one of magnesium oxide, magnesium acetate and magnesium carbonate. Adding a magnesium source will help promote the conversion of alumina into α-alumina.

The amount of fluoride added is 0.1 to 2% of the raw material, and the fluoride includes ammonium fluoride and/or aluminum fluoride. Adding fluoride will help reduce the roasting time and temperature, thereby reducing energy consumption.

Preferably, the shape of the carrier precursor can be a Raschig ring, a porous pillar, a cylinder or a four-leaf clover.

Step S3, prepare a porous support of α-alumina:

The carrier precursor is calcined at high temperature at 1200 to 1500°C to obtain a porous carrier of α-alumina.

By roasting the carrier precursor at high temperature, it is beneficial to obtain the α phase in a shorter time; the characteristics of the porous carrier to obtain α-alumina are: ≤3㎡/g, water absorption ≥42%, compressive strength ≥ 100N/piece, pore volume ≥0.24.

Among them, the roasting temperature is 1200-1500°C, preferably 1250-1450°C, and more preferably 1300-1400°C; the roasting time is 4-6 hours

Specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

Example 1

This embodiment provides a method of using spent catalyst to prepare an ethylene oxide catalyst carrier, including:

The recycled alumina (purity ≥99%) after extracting precious metals is dried and ground to D90≈20 microns, with 0.5 parts by weight of recycled alumina, 3.5 parts by weight of gibbsite and 4 parts by weight of monohydrate As raw material, add additives (5-20% activated carbon powder, 0.1-1.5% magnesium oxide, and 0.1-2% ammonium fluoride), mix evenly, add binder, and form in a high-pressure press to obtain a carrier Precursor; after being calcined at a high temperature of 1300°C, a porous carrier of α-alumina is obtained.

The characteristics of the porous carrier of α-alumina in this embodiment are: specific surface is 2㎡/g, water absorption is 47.3%, compressive strength is 116N/piece, and pore volume is 0.36.

Example 2

This embodiment provides a method of using spent catalyst to prepare an ethylene oxide catalyst carrier, including:

The recycled alumina (purity ≥99%) after extracting precious metals is dried and ground to D90≈20 microns, with 1 part by weight of recycled alumina, 3.25 parts by weight of gibbsite and 3.75 parts by weight of monohydrate. Raw materials, add additives (5-20% activated carbon powder, 0.1-1.5% magnesium oxide, and 0.1-2% ammonium fluoride), mix evenly and then add them to a high-pressure press for molding to obtain a carrier precursor; After roasting and shaping, a porous carrier of α-alumina is obtained.

The characteristics of the porous carrier of α-alumina in this embodiment are: specific surface is 3㎡/g, water absorption is 45.56%, compressive strength is 141N/piece, and pore volume is 0.33.

Example 3

This embodiment provides a method of using spent catalyst to prepare an ethylene oxide catalyst carrier, including:

The recycled alumina (purity ≥99%) after extracting precious metals is dried and ground to D90≈20 microns, using 1.5 parts by weight of recycled alumina, 3 parts by weight of gibbsite and 3.5 parts by weight of monohydrate as raw materials , add additives (5 to 20% activated carbon powder, 0.1 to 1.5% magnesium oxide, and 0.1 to 2% ammonium fluoride), mix evenly, then add it to a high-pressure press for molding to obtain a carrier precursor; roast it at a high temperature of 1300°C finalize Finally, a porous support of α-alumina is obtained.

The characteristics of the porous carrier of α-alumina in this embodiment are: specific surface of 1㎡/g, water absorption rate of 42%, compressive strength of 181.4N/piece, and pore volume of 0.25.

Example 4

This embodiment provides a method of using spent catalyst to prepare an ethylene oxide catalyst carrier, including:

The recycled alumina (purity ≥99%) after extracting precious metals is dried and ground to D90≈20 microns, with 2 parts by weight of recycled alumina, 2.75 parts by weight of gibbsite and 3.25 parts by weight of monohydrate. Raw materials, add additives (5-20% activated carbon powder, 0.1-1.5% magnesium oxide, and 0.1-2% ammonium fluoride), mix evenly and then add them to a high-pressure press for molding to obtain a carrier precursor; After roasting and shaping, a porous carrier of α-alumina is obtained.

The characteristics of the porous carrier of α-alumina in this embodiment are: specific surface is 2㎡/g, water absorption is 40.82%, compressive strength is 195.8N/piece, and pore volume is 0.24.

Example 5

This embodiment provides a method of using spent catalyst to prepare an ethylene oxide catalyst carrier, including:

The recycled alumina (purity ≥99%) after extracting precious metals is dried and ground to 30 microns, using 1.5 parts by weight of recycled alumina, 3 parts by weight of gibbsite and 3.5 parts by weight of monohydrate as raw materials. Add additives (5 to 20% activated carbon powder, 0.1 to 1.5% magnesium oxide, and 0.1 to 2% ammonium fluoride), mix evenly, and then add it to a high-pressure press for molding to obtain a carrier precursor; it is roasted at 1300°C to finalize the shape. Finally, a porous support of α-alumina is obtained.

The characteristics of the porous carrier of α-alumina in this embodiment are: the specific surface is 2㎡/g, and the compressive strength is 173N/piece, pore volume is 0.26.

Example 6

This embodiment provides a method of using spent catalyst to prepare an ethylene oxide catalyst carrier, including:

The recycled alumina (purity ≥99%) after extracting precious metals is dried and ground to 40 microns, using 1.5 parts by weight of recycled alumina, 3 parts by weight of gibbsite and 3.5 parts by weight of monohydrate as raw materials. Add additives (5 to 20% activated carbon powder, 0.1 to 1.5% magnesium oxide, and 0.1 to 2% ammonium fluoride), mix evenly, and then add it to a high-pressure press for molding to obtain a carrier precursor; it is roasted at 1300°C to finalize the shape. Finally, a porous support of α-alumina is obtained.

The characteristics of the porous carrier of α-alumina in this embodiment are: the specific surface is 1㎡/g, the compressive strength is 134.4N/piece, and the pore volume is 0.28.

Example 7

This embodiment provides a method of using spent catalyst to prepare an ethylene oxide catalyst carrier, including:

The recycled alumina (purity ≥99%) after extracting precious metals is dried and ground to 50 microns, using 1.5 parts by weight of recycled alumina, 3 parts by weight of gibbsite and 3.5 parts by weight of monohydrate as raw materials. Add additives (5 to 20% activated carbon powder, 0.1 to 1.5% magnesium oxide, and 0.1 to 2% ammonium fluoride), mix evenly, and then add it to a high-pressure press for molding to obtain a carrier precursor; it is roasted at 1300°C to finalize the shape. Finally, a porous support of α-alumina is obtained.

The characteristics of the porous carrier of α-alumina in this embodiment are: specific surface is 2㎡/g, compressive strength is 121.1N/piece, and pore volume is 0.33

Example 8

This embodiment provides a method of using spent catalyst to prepare an ethylene oxide catalyst carrier, including:

The recycled alumina (purity ≥99%) after extracting precious metals is dried and ground to 60 microns, using 1.5 parts by weight of recycled alumina, 3 parts by weight of gibbsite and 3.5 parts by weight of monohydrate as raw materials. Add additives (5 to 20% activated carbon powder, 0.1 to 1.5% magnesium oxide, and 0.1 to 2% ammonium fluoride), mix evenly, and then add it to a high-pressure press for molding to obtain a carrier precursor; it is roasted at 1300°C to finalize the shape. Finally, a porous support of α-alumina is obtained.

The characteristics of the porous carrier of α-alumina in this embodiment are: specific surface is 3㎡/g, compressive strength is 103.5N/piece, and pore volume is 0.38.

Example 9

This embodiment provides a method of using spent catalyst to prepare an ethylene oxide catalyst carrier, including:

The recovered alumina (purity 99wt%) after extracting the platinum metal from the platinum-containing waste catalyst is dried and ground to D90≈50 microns, with 3.5 parts by weight of recovered alumina, 1 part by weight of gibbsite and 3 parts by weight part of monohydrate as raw material, add additives (10% polyethylene, 1.0% magnesium oxide, and 1.0% ammonium fluoride), mix evenly, and then add it to a high-pressure press for molding to obtain a carrier precursor; after heating at 1300°C After high-temperature roasting and shaping, a porous carrier of α-alumina is obtained.

Specific surface 2.2, water absorption 41%, strength 111.4, pore volume 0.2.

Example 10

This embodiment provides a method of using spent catalyst to prepare an ethylene oxide catalyst carrier, including:

The recovered alumina (purity 99wt%) after extracting palladium metal from the palladium-containing waste catalyst is dried After grinding to D90≈5 microns, use 3.5 parts by weight of recycled alumina, 4 parts by weight of gibbsite and 3 parts by weight of gibbsite as raw materials, and add additives (5% petroleum coke powder, 1.5% Magnesium carbonate, and 0.1% ammonium fluoride) are mixed evenly and then added to a high-pressure press for molding to obtain a carrier precursor; after being roasted and shaped at a high temperature of 1500°C, an α-alumina porous carrier is obtained.

Specific surface 1.5, water absorption 40%, strength 351, pore volume 0.2.

Example 11

This embodiment provides a method of using spent catalyst to prepare an ethylene oxide catalyst carrier, including:

The recovered alumina (purity is 98wt%) after extracting the silver metal from the silver-containing waste catalyst is dried and ground to D90≈100 microns. 0.5 parts by weight of recovered alumina, 1 part by weight of gibbsite and 1 part by weight 20% of monohydrate as raw material, add additives (20% graphite, 0.1% magnesium acetate, and 2% aluminum fluoride), mix evenly, and then add it to a high-pressure press for molding to obtain a carrier precursor; after being heated at 1200°C After roasting and shaping, a porous carrier of α-alumina is obtained. Specific surface 2, water absorption 45%, strength 102N, pore volume 0.31

The parameters in the examples and the properties of the porous carrier of α-alumina prepared are analyzed below:

(1) One of the difficulties in this method of using spent catalyst to prepare an ethylene oxide catalyst carrier provided by this application is the selection of the amount of recycled alumina. Therefore, the data of Examples 1 to 4 are summarized and analyzed below, as shown in Table 1:

Table 1.

It can be seen from Table 1 that when the particle size of recycled alumina is small (20 μm), and when the amount of recycled alumina is increased (0.5 parts by weight → 1 part by weight), the pore volume of the porous carrier of α-alumina finally produced will decrease (0.36→0.25). When the amount of recycled alumina added is less than 0.5, the amount of recycled alumina used is too small; when the amount of recycled alumina added is greater than 3.5, the pore volume and water absorption rate will decrease significantly.

(2) The second difficulty in the method provided by this application for using spent catalyst to prepare an ethylene oxide catalyst carrier lies in the particle size selection of recycled alumina. Therefore, the data of Examples 5 to 8 are summarized and analyzed below, as shown in Table 2:

Table 2.

It can be seen from Table 2 that when the addition ratio of recycled alumina is the same (both 1.5 parts by weight), the particle size becomes larger (30 μm → 60 μm), and the pore volume of the porous carrier of α-alumina finally produced also increases accordingly. (0.26→0.38). The increase in pore volume helps to load active ingredients. When the particle size of alumina is <5 μm, the porous carrier of α-alumina obtained has extremely low pore volume; when the particle size of alumina is >100 μm, the porous carrier obtained The strength of the porous support of α-alumina decreases significantly

Finally, it should be noted that the above descriptions are only preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalents or substitutions made within the spirit and principles of the invention Replacements, improvements, etc. shall be included in the protection scope of the present invention.

Claims (9)

A method for preparing an ethylene oxide catalyst carrier using spent catalyst, which is characterized by including: After drying the alumina recovered from the spent catalyst, grind it to 5-100 μm; Mix 0.5-3.5 parts by weight of the alumina, 1-4 parts by weight of gibbsite and 1-4 parts by weight of gibbsite as raw materials, add additives and binders, and press and shape to obtain a carrier Precursors; and The carrier precursor is calcined at high temperature at 1200 to 1500° C. to obtain an α-alumina porous carrier. The method of using spent catalyst to prepare an ethylene oxide catalyst carrier according to claim 1, wherein the temperature at which the recovered alumina is dried is 80 to 200°C. The method for preparing an ethylene oxide catalyst carrier by using a spent catalyst according to claim 1, wherein the spent catalyst includes at least one of a platinum-containing catalyst, a palladium-containing catalyst and a silver-containing catalyst. The method of using spent catalyst to prepare an ethylene oxide catalyst carrier according to claim 1, characterized in that before drying the alumina, it further includes the step of passing the recovered alumina through a 20-40 mesh sieve. The method of using spent catalyst to prepare ethylene oxide catalyst carrier according to claim 1, wherein the auxiliary agent includes carbon material, magnesium source and fluoride; The added amount of the carbon material is 5-20% of the weight of the raw material; the added amount of the magnesium source is 0.1-1.5% of the weight of the raw material; the added amount of the fluoride is 0.1% of the weight of the raw material ~2%. The method of using spent catalyst to prepare an ethylene oxide catalyst carrier according to claim 5, wherein the carbon material includes at least one of activated carbon powder, petroleum coke powder, graphite, polyethylene and polypropylene. The method for preparing ethylene oxide catalyst carrier by using spent catalyst according to claim 5, characterized in that the magnesium source includes at least one of magnesium oxide, magnesium acetate and magnesium carbonate. The method of claim 5, wherein the fluoride includes ammonium fluoride and/or aluminum fluoride. The porous carrier of α-alumina prepared according to the method of using spent catalyst to prepare an ethylene oxide catalyst carrier according to any one of claims 1 to 8, characterized in that the porous carrier of α-alumina has characteristics It is: specific surface ≤3㎡/g, water absorption ≥40%, compressive strength ≥100N/piece, pore volume ≥0.20.