Catalyst for HCl oxidation and preparation method and application thereof

Abstract

The invention provides a catalyst for HCl oxidation and a preparation method and application thereof. The catalyst for HCl oxidation has the following characteristics: a) the mass content of an iron element in an alumina carrier is 1ppm-1.5%; and b) when the catalyst is characterized by adopting a hydrogen temperature programmed reduction (H2-TPR) method, the ratio of the hydrogen consumption on the low-temperature side to the hydrogen consumption on the high-temperature side is 0.5-2.5. The catalyst has the advantages of high activity, low copper loss, high stability and the like, and can be used in the technical field of preparation of chlorine through hydrogen chloride oxidation.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing chlorine gas by hydrogen chloride oxidation, and particularly relates to a catalyst for HCl oxidation, a preparation method thereof, and an application thereof. Background Art

[0002] In the production processes of many bulk chemicals such as polyurethane intermediates, polyvinyl chloride, organic chlorine intermediates (chlorobenzene, chloroacetic acid, benzyl chloride, chlorotoluene), epoxy resins, etc., chlorine gas is often required as a raw material, and a large amount of hydrogen chloride is by-produced. The proper treatment of the by-produced hydrogen chloride is directly related to the expansion of the production capacity of the above-mentioned bulk chemicals. The simplest way to treat the by-produced hydrogen chloride is to directly absorb it with an alkali, but this will produce a large amount of waste brine that is difficult to recycle. The catalytic oxidation of hydrogen chloride to chlorine gas can not only treat the by-produced hydrogen chloride on a large scale, but also the generated chlorine gas can continue to be used as a raw material, which is the best solution to achieve nearly 100% chlorine recycling. The key to this solution lies in the development of an efficient catalyst.

[0003] In the reported literature, catalysts obtained with transition metals such as gold, ruthenium, chromium, and copper as active components have good activity for the oxidation of hydrogen chloride to chlorine gas. However, the noble metal gold and ruthenium-based catalysts among them have high costs and high requirements for the purity of reaction raw materials, and it is difficult to directly use them in industrial devices with complex tail gas components. The chromium-based catalyst has high toxicity and causes great environmental pollution. Therefore, the copper-based catalyst has received extensive attention due to its cost advantage and environmental friendliness.

[0004] The active component of the copper-based catalyst for hydrogen chloride oxidation is copper chloride, but the boiling point of copper chloride is relatively low. Under high-temperature working conditions (>350 °C), copper chloride will gradually volatilize and migrate with the extension of the use time.

[0005] To inhibit the volatilization of copper chloride and obtain a catalyst with high activity and high stability, researchers have made a lot of efforts. Selecting a suitable carrier to enhance its anchoring effect on copper chloride, selecting suitable alkali metal elements, rare earth metal elements, and other additives to inhibit its volatilization and adhesion are all effective measures to improve the activity and stability of the catalyst. However, a large number of literatures mainly focus on the optimization of the catalyst formula, and few pay attention to the influence of impurities in the carrier or metal salt on the catalyst performance.

[0006] US3260678A reports a copper-containing catalyst supported on silica gel, which requires that the specific surface area of the carrier > 200 m2 / g and the average pore diameter > 6 nm. The HCl conversion rate of this catalyst reaches 80% at 350 °C, but according to Example 1, the reaction space velocity is very low, which is 40 L(HCl)·kg (cat) -1 ·h -1 .

[0007] CN108097232A reports a catalyst prepared by mixing two powders of different formulas, which has good comprehensive performance and an HCl conversion rate of 85% at a reaction temperature of 350-360°C. However, the preparation process of the catalyst is relatively complicated and the catalyst strength still needs to be further improved.

[0008] CN111450881A reports a modified Cu-Al hydrotalcite catalyst for the production of chlorine by oxidation of hydrogen chloride. The catalyst has the advantages of low loss of active components, low abrasion, and good hydrothermal stability. The HCl conversion rate at a reaction temperature of 350-360°C is greater than 86%, but the catalyst preparation process is complicated.

[0009] CN117019127A reports a method for improving the thermal stability of a catalyst by modifying a catalyst carrier to improve the thermal stability of the carrier, thereby improving the high-temperature thermal stability and long-term durability of the catalyst. However, a polyanion compound D is introduced during the preparation process, the preparation process is relatively complicated, and the catalyst cost is slightly high.

[0010] Based on the above research background, it is necessary to develop a catalyst with simple preparation process, high activity, low copper loss and high stability. Summary of the invention

[0011] In view of the deficiencies in the prior art, the present invention provides a catalyst for HCl oxidation and a preparation method thereof. The catalyst has the advantages of high activity, low copper loss and high stability, and can be used in the technical field of preparing chlorine by hydrogen chloride oxidation.

[0012] The inventors unexpectedly discovered during the research process of a catalyst for catalytic oxidation of hydrogen chloride to prepare chlorine that, for a Cu-based catalyst using alumina as a carrier, the iron element contained in the alumina carrier raw material will affect the performance of the catalyst. It was further discovered that by controlling the iron content in the raw material within a specific range, and when the catalyst is subjected to programmed temperature increase (H2-TPR characterization) under H2 atmosphere, the ratio of the hydrogen consumption on the low temperature side (100-310°C) to the hydrogen consumption on the high temperature side (310-450°C) is between 0.5 and 2.5, the catalyst has the characteristics of high activity, low copper loss and high stability.

[0013] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0014] The present invention provides a catalyst for HCl oxidation, wherein the catalyst is an alumina-supported Cu-based catalyst having the following characteristics:

[0015] a) The mass content of iron element in the alumina support is 1 ppm to 1.5%, such as 1 ppm, 50 ppm, 100 ppm, 500 ppm, 900 ppm, 0.1%, 0.3%, 0.6%, 0.9%, 1.2%, 1.5%;

[0016] b) When the catalyst is characterized by the hydrogen temperature-programmed reduction (H2-TPR) method, the ratio of the hydrogen consumption on the low-temperature side to the hydrogen consumption on the high-temperature side is 0.5 to 2.5, such as 0.5, 0.8, 1.1, 1.4, 1.7, 2.0, 2.3, 2.5, preferably between 0.6 and 2.5.

[0017] The alumina-supported Cu-based catalyst of the present invention is further loaded with an alkali metal element, a rare earth metal element, and optionally other elements;

[0018] Preferably, the alkali metal element is selected from at least one of potassium and sodium;

[0019] Preferably, the rare earth element is selected from at least one of cerium, lanthanum, praseodymium, neodymium, and samarium, and more preferably at least one of lanthanum, praseodymium, and neodymium;

[0020] Preferably, the other elements are selected from at least one of elements such as magnesium, calcium, barium, manganese, iron, cobalt, nickel, zinc, and titanium, etc.

[0021] For the alumina-supported Cu-based catalyst of the present invention, based on 100% of the total mass of the catalyst, the mass content of the Cu element is 1 to 21%. Such as 1, 3, 6, 9, 12, 15, 18, 21%, preferably 4 to 16%, more preferably 5 to 11.5%; the Cu element is loaded on the alumina support in the form of copper oxide or copper salt such as copper chloride;

[0022] Preferably, the mass content of the alkali metal element is 0.5 to 10%, such as 0.5, 1, 3, 5, 7, 9, 10%, preferably 2 to 7%, more preferably 2.5 to 6%; the mass content of the rare earth metal element is 0.5 to 15%, such as 0.5, 1, 3, 5, 7, 9, 11, 13, 15%, preferably 1 to 11%, more preferably 2 to 9%; the mass percentage of the other elements is 0 to 10%, such as 0, 0.1, 1, 3, 5, 7, 9, 10%, preferably 1 to 7%, more preferably 2 to 6%; the alkali metal element, the rare earth metal element, and the other elements are all loaded on the alumina support in the form of oxides or metal salts such as chlorides.

[0023] In the present invention, for the alumina support described in feature a), its raw material is an alumina hydrate containing iron element. Based on the total mass of the alumina hydrate containing iron element being 100%, the mass content of the iron element is 0.85 ppm to 1.65%, such as 0.85 ppm, 50 ppm, 100 ppm, 500 ppm, 900 ppm, 0.1%, 0.3%, 0.6%, 0.9%, 1.2%, 1.5, 1.65%.

[0024] In the present invention, the low-temperature side described in feature b) refers to the temperature range of 100 to 310 °C, and the high-temperature side refers to the temperature range of 310 to 450 °C.

[0025] The present invention also provides a method for preparing the above-mentioned catalyst for HCl oxidation, and the steps include:

[0026] (1) Crushing the alumina hydrate containing iron element to obtain a solid powder with an average particle size of 1 to 5 μm, dispersing it in water, stirring and mixing evenly, and then adding an acidic liquid to obtain a slurry support;

[0027] (2) Mixing the mixed salt solution containing copper element, alkali metal element, rare earth metal element, and optionally other elements with the slurry support in step (1) evenly to obtain a paste, and then spray-drying and calcining to obtain a catalyst for HCl oxidation.

[0028] In the present invention, for the alumina hydrate containing iron element described in step (1), based on the total mass of the alumina hydrate containing iron element, the mass content of the iron element is 0.85 ppm to 1.65%, such as 0.85 ppm, 50 ppm, 100 ppm, 500 ppm, 900 ppm, 0.1%, 0.3%, 0.6%, 0.9%, 1.2%, 1.5, 1.65%.

[0029] In the present invention, the concentration of the solid powder dispersed in water in step (1) is 10 to 60 wt%, such as 10, 20, 30, 40, 50, 60 wt%.

[0030] In the present invention, for the acidic liquid described in step (1), the acid therein is selected from at least one of nitric acid, hydrochloric acid, phosphoric acid, etc.;

[0031] Preferably, the acidic liquid is an aqueous solution of an acid, and the concentration is 30 to 60 wt%, such as 30, 35, 40, 45, 50, 55, 60 wt%.

[0032] Preferably, the mass ratio of the acidic liquid to the mass of the solid powder is 0.03 to 0.12:1, such as 0.03:1, 0.05:1, 0.07:1, 0.09:1, 0.11:1, 0.12:1.

[0033] In the present invention, the mixed salt solution containing copper element, alkali metal element, rare earth metal element and optionally other elements in step (2) is such that the salts therein are selected from inorganic salts such as nitrates, chlorides, carbonates, etc.;

[0034] Preferably, in the mixed salt solution, the concentration of copper salt is 5-12 wt%, such as 5, 7, 9, 11, 12 wt%; the concentration of alkali metal element salt is 0.5-6 wt%; the concentration of rare earth metal element salt is 1-12 wt%, such as 1, 3, 5, 7, 9, 12 wt%; the concentration of other element salts is 0-10 wt%, such as 0, 0.1, 2, 4, 6, 8, 10 wt%, preferably 0.15-6.5 wt%;

[0035] Preferably, the alkali metal element is selected from at least one of potassium and sodium;

[0036] Preferably, the rare earth element is selected from at least one of cerium, lanthanum, praseodymium, neodymium, samarium, and more preferably at least one of lanthanum, praseodymium, and neodymium;

[0037] Preferably, the other elements are selected from at least one of elements such as magnesium, calcium, barium, manganese, iron, cobalt, nickel, zinc, titanium, etc.

[0038] In the present invention, the mass ratio of the mixed salt solution containing copper element, alkali metal element, rare earth metal element and optionally other elements in step (2) to the slurry carrier in step (1) is 0.2-3:1, such as 0.2:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1.

[0039] In the present invention, the calcination in step (2) is carried out in an inert atmosphere containing oxygen;

[0040] For the calcination, the temperature is 400-650 °C, such as 400, 450, 500, 550, 600, 650 °C, and the time is 0.5-8 h, such as 0.5, 1, 3, 5, 7, 8 h;

[0041] Preferably, in the inert atmosphere, the volume content of oxygen is 1-30%, such as 1, 5, 10, 15, 20, 25, 30%; the inert atmosphere is selected from nitrogen, helium, etc., preferably nitrogen.

[0042] In the preparation method of the present invention, the mixing, dispersion, stirring, spray drying, etc. are conventional operation methods in the field, and there are no special requirements in the present invention.

[0043] The catalyst of the present invention is applicable to the process of oxidizing HCl to chlorine, especially the fluidized bed reactor process.

[0044] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0045] The alumina-supported Cu-based catalyst provided by the present invention has high activity and low copper loss during the reaction of hydrogen chloride oxidation to chlorine, and can stably obtain chlorine with a high yield. Specific Embodiments

[0046] To better understand the technical solution of the present invention, the content of the present invention will be further elaborated below in conjunction with embodiments. However, the content of the present invention is not limited to the following embodiments only.

[0047] The main sources of special raw materials in the embodiments and comparative examples of the present invention are as follows.

[0048] Aluminum hydroxide containing iron element: purchased from Suzhou Baird New Materials Technology Co., Ltd.;

[0049] Unless otherwise specified, other raw materials and reagents are obtained through commercial channels on the market.

[0050] The following is the method for testing the activity of the hydrogen chloride oxidation catalyst used in the embodiments or comparative examples:

[0051] 1. Catalyst performance test method

[0052] Put 1 kg of the catalyst into a fluidized bed reactor with an inner diameter of 40 mm and a height of 1700 mm. Using hydrogen chloride / oxygen = 2 / 1 in molar ratio as the raw material, carry out the reaction of hydrogen chloride oxidation to chlorine under the conditions of HCl mass space velocity of 0.40 h -1 , reaction temperature of 340 - 350 °C, and reaction pressure of 0.3 MPa (absolute pressure). During the catalyst reaction performance test, samples are taken 3 times every 24 h for analysis, and the average conversion rate during the entire operation process is used as the conversion rate of the catalyst for hydrogen chloride.

[0053] 2. Calculation method of hydrogen chloride conversion rate:

[0054] After the reaction of hydrogen chloride oxidation to chlorine is completed, the product gas is introduced into an aqueous potassium iodide solution with a mass fraction of 15% for absorption. The iodine in the absorption solution is titrated with an aqueous sodium thiosulfate solution with a concentration of 0.1 mol / L, and the residual HCl amount in the absorption solution is titrated with an aqueous sodium hydroxide solution with a concentration of 0.1 mol / L to calculate the amount of chlorine generated and the amount of residual HCl.

[0055] 3. Catalyst H2-TPR characterization method:

[0056] Carrier gas: H2, H2 mixed with inert gas

[0057] Carrier gas flow rate: 40 ml / min

[0058] Catalyst sample amount: generally 50 - 200 mg

[0059] Particle size: 20 - 40 mesh

[0060] Heating rate: 10 °C / min

[0061] Detector: TCD

[0062] 4. Elemental analysis of the catalyst sample was carried out using ICP testing.

[0063] Example 1

[0064] (1) Catalyst preparation:

[0065] 3076.9 g of alumina hydrate with an iron element mass content of 50 ppm was pulverized to obtain a solid powder with an average particle size of 1 - 5 μm, dispersed in 17.436 kg of water, stirred and mixed evenly, and then 338.5 g of a hydrochloric acid aqueous solution with a concentration of 35 wt% was added to obtain 20.851 kg of a slurry support;

[0066] 690.2 g of copper nitrate, 291.2 g of potassium chloride, 94 g of praseodymium nitrate, 232.5 g of lanthanum chloride, 277.8 g of neodymium nitrate, 119.4 g of magnesium chloride, 397 g of manganese nitrate were mixed with 6 kg of water to prepare 8.102 kg of a mixed brine solution, which was mixed evenly with the slurry support obtained in step (1) to obtain a paste, and then spray-dried and calcined at 450 °C for 7 h in a nitrogen atmosphere with an oxygen volume content of 18% to obtain a catalyst for HCl oxidation.

[0067] The prepared catalyst uses alumina as the support (where the iron element mass content is 50.5 ppm). Based on 100% of the total mass of the catalyst, the loaded copper element content is 6 wt%, the alkali metal element is potassium with a content of 5%, the rare earth metal element is praseodymium with a content of 1%, lanthanum with a content of 3%, neodymium with a content of 3%, and other active metals are magnesium with a content of 1% and manganese with a content of 4%. Each element is loaded on the alumina support in the form of an oxide or chloride.

[0068] (2) Catalyst characterization and performance testing:

[0069] The above catalyst was characterized by H2-TPR. The mass ratio of the hydrogen consumption on the low-temperature side (100 - 310 °C) to the hydrogen consumption on the high-temperature side (310 - 450 °C) was 0.6.

[0070] The catalyst activity was evaluated according to the aforementioned catalyst performance test method. After continuous reaction for 100 h, the HCl conversion rate was 85.4%. At the same time, the mass content of Cu element in the catalyst was tested to be 5.99%. Under this condition, after continuous reaction for 3000 h, the HCl conversion rate was 86.2%. At the same time, the mass content of Cu element in the catalyst was tested to be 5.93%, and the fluidization performance was good.

[0071] Example 2

[0072] (1) Catalyst preparation:

[0073] 3100 g of alumina hydrate with an iron element mass content of 1% was crushed to obtain solid powder with an average particle size of 1 - 5 μm, dispersed in 2.54 kg of water, stirred and mixed evenly, and then 108.5 g of nitric acid aqueous solution with a concentration of 46 wt% was added to obtain 5.7485 kg of a slurry support.

[0074] 673.6 g of copper chloride, 53.55 g of potassium chloride, 211.9 g of sodium chloride, 174.7 g of lanthanum nitrate, 69.7 g of neodymium chloride, 114.9 g of calcium nitrate, 91.2 g of manganese nitrate, 61.9 g of nickel chloride, 87 g of cobalt nitrate were mixed with 10 kg of water to prepare 11.538 kg of a mixed brine solution, which was mixed evenly with the slurry support obtained in step (1) to obtain a paste, and then spray-dried and calcined at 500 °C for 6 h in a nitrogen atmosphere with an oxygen volume content of 6% to obtain a catalyst for HCl oxidation.

[0075] The prepared catalyst uses alumina as the support (where the iron element mass content is 1.11%). Based on the total mass of the catalyst being 100%, the loaded copper element content is 9 wt%, the alkali metal element is potassium with a content of 1% and sodium with a content of 3%, the rare earth metal element is lanthanum with a content of 2% and neodymium with a content of 1%, and the other active metals are calcium with a content of 1%, manganese with a content of 1%, nickel with a content of 1%, and cobalt with a content of 1%. Each element is loaded on the alumina support in the form of an oxide or chloride.

[0076] (2) Catalyst characterization and performance test:

[0077] The above catalyst was characterized by H2-TPR. The mass ratio of the hydrogen consumption on the low-temperature side (100 - 310 °C) to the hydrogen consumption on the high-temperature side (310 - 450 °C) was 2.

[0078] The catalyst activity was evaluated according to the aforementioned catalyst performance test method. After continuous reaction for 100 h, the HCl conversion rate was 86%. At the same time, the mass content of Cu element in the catalyst was tested to be 8.98%. Under this condition, after continuous reaction for 3000 h, the HCl conversion rate was 85.8%. At the same time, the mass content of Cu element in the catalyst was tested to be 8.91%, and the fluidization performance was good.

[0079] Example 3

[0080] (1) Catalyst preparation:

[0081] Using 3100 g of alumina hydrate with an iron element mass content of 1000 ppm as the carrier raw material, it was pulverized to obtain solid powder with an average particle size of 1 - 5 μm, dispersed in 7.23 kg of water, stirred and mixed evenly, and then 186 g of nitric acid aqueous solution with a concentration of 55 wt% was added to obtain 10.516 kg of a slurry carrier;

[0082] 837.5 g of copper chloride, 54.47 g of potassium chloride, 71.83 g of sodium chloride, 71.87 g of praseodymium chloride, 266.5 g of lanthanum nitrate, 86.6 g of neodymium nitrate, 111.6 g of magnesium chloride, 79.1 g of calcium chloride, 92.8 g of manganese nitrate were mixed with 15 kg of water to prepare 16.672 kg of a mixed brine solution, which was mixed evenly with the slurry carrier obtained in step (1) to obtain a paste, and then spray-dried and calcined at 630 °C for 2 h in a nitrogen atmosphere with an oxygen volume content of 25% to obtain a catalyst for HCl oxidation.

[0083] The prepared catalyst uses alumina as the carrier (where the iron element mass content is 1088 ppm). Based on the total mass of the catalyst being 100%, the loaded copper element content is 11 wt%, the alkali metal element potassium content is 1%, the sodium content is 1%, the rare earth metal element praseodymium content is 1%, the lanthanum content is 3%, the neodymium content is 1%, and the other active metal calcium element is 1%, the manganese content is 1%, and the magnesium content is 1%. Each element is loaded on the alumina carrier in the form of an oxide or chloride.

[0084] (2) Catalyst characterization and performance testing:

[0085] The catalyst was characterized by H2-TPR. The mass ratio of hydrogen consumption on the low-temperature side (100 - 310 °C) to hydrogen consumption on the high-temperature side (310 - 450 °C) was 1.1.

[0086] The above catalyst was characterized by H2-TPR. The mass ratio of hydrogen consumption on the low-temperature side (100 - 310 °C) to hydrogen consumption on the high-temperature side (310 - 450 °C) was 1.1.

[0087] According to the above-mentioned catalyst performance testing method, the catalyst activity was evaluated. After continuous reaction for 100 h, the HCl conversion rate was 85.7%. At the same time, the mass content of Cu element in the catalyst was measured to be 10.98%. After continuous reaction for 3000 h under this condition, the HCl conversion rate was 86.8%. At the same time, the mass content of Cu element in the catalyst was measured to be 10.89%, and the fluidization performance was good.

[0088] Comparative Example 1

[0089] (1) Catalyst preparation:

[0090] Referring to Example 1, the difference is only that: the carrier raw material is replaced with aluminum oxide hydrate with an iron content of 2 wt%, and the catalyst is prepared.

[0091] The prepared catalyst uses alumina as the carrier (where the mass content of iron element is 2.019 wt%). Based on the total mass of the catalyst being 100%, the loaded copper element content is 6 wt%, the alkali metal element potassium content is 5%, the rare earth metal element praseodymium content is 1%, the lanthanum content is 3%, the neodymium content is 3%, and the other active metal magnesium content is 1%, and the manganese content is 4%. Each element is loaded on the alumina carrier in the form of an oxide or chloride.

[0092] (2) Catalyst characterization and performance testing:

[0093] The catalyst was characterized by H2-TPR, and the ratio of hydrogen consumption on the low-temperature side (100 - 310 °C) to the hydrogen consumption on the high-temperature side (310 - 450 °C) was 3.

[0094] According to the aforementioned catalyst performance testing method, the catalyst activity was evaluated. After continuous reaction for 100 h, the HCl conversion rate was 83.1%. At the same time, the mass content of Cu element in the catalyst was tested to be 13.97%. After continuous reaction for 3000 h under this condition, the HCl conversion rate was 79%. At the same time, the mass content of Cu element in the catalyst was tested to be 13.75%, and the fluidization performance of the catalyst deteriorated.

[0095] Comparative Example 2

[0096] (1) Catalyst preparation:

[0097] Referring to Example 1, the difference is only that: the carrier raw material is replaced with alumina with an iron content of 2.5 wt% as the carrier raw material, and the catalyst precursor is prepared and calcined at 650 °C for 5 h to obtain the finished catalyst.

[0098] The prepared catalyst uses alumina as the carrier (where the mass content of iron element is 2.524 wt%). Based on the total mass of the catalyst being 100%, the loaded copper element content is 6 wt%, the alkali metal element potassium content is 5%, the rare earth metal element praseodymium content is 1%, the lanthanum content is 3%, the neodymium content is 3%, and the other active metal magnesium content is 1%, and the manganese content is 4%. Each element is loaded on the alumina carrier in the form of an oxide or chloride.

[0099] (2) Catalyst characterization and performance testing:

[0100] The catalyst was characterized by H2-TPR. The ratio of hydrogen consumption on the low-temperature side (100 - 310 °C) to that on the high-temperature side (310 - 450 °C) was 0.41.

[0101] According to the above-mentioned catalyst performance test method, the catalyst activity was evaluated. After continuous reaction for 100 h, the HCl conversion rate was 70.1%. At the same time, the mass content of Cu element in the test sample was 7.95%. After continuous reaction for 3000 h under this condition, the HCl conversion rate was 65.8%. At the same time, the mass content of Cu element in the test sample was 7.91%.

Claims

1. A catalyst for HCl oxidation, which is an alumina-supported Cu-based catalyst and has the following characteristics: a) The mass content of iron element in the alumina support is 1 ppm to 1.5%; b) When the catalyst is characterized by the hydrogen temperature-programmed reduction (H2-TPR) method, the ratio of the hydrogen consumption on the low-temperature side to the hydrogen consumption on the high-temperature side is 0.5 to 2.5, preferably between 0.6 and 2.

5.

2. The catalyst for HCl oxidation according to claim 1, characterized in that, Loaded with alkali metal elements, rare earth metal elements, and optionally other elements; Preferably, the alkali metal element is selected from at least one of potassium and sodium; Preferably, the rare earth element is selected from at least one of cerium, lanthanum, praseodymium, neodymium, and samarium, more preferably at least one of lanthanum, praseodymium, and neodymium; Preferably, the other element is selected from at least one of magnesium, calcium, barium, manganese, iron, cobalt, nickel, zinc, and titanium elements.

3. The catalyst for HCl oxidation according to claim 1, wherein Based on 100% of the total mass of the catalyst, the mass content of the Cu element is 1% to 21%, preferably 4% to 16%, more preferably 5% to 11.5%; Preferably, the mass content of the alkali metal element is 0.5% to 10%, preferably 2% to 7%, more preferably 2.5% to 6%; the mass content of the rare earth metal element is 0.5% to 15%, preferably 1% to 11%, more preferably 2% to 9%; the mass percentage of the other element is 0% to 10%, preferably 1% to 7%, more preferably 2% to 6%.

4. The catalyst for HCl oxidation according to claim 1, characterized in that, For the alumina support in feature a), its raw material is an alumina hydrate containing iron element. Based on 100% of the total mass of the alumina hydrate containing iron element, the mass content of iron element is 0.85 ppm to 1.65%.

5. The catalyst for HCl oxidation according to claim 1, characterized in that, For feature b), the low-temperature side refers to the temperature range of 100 to 310 °C, and the high-temperature side refers to the temperature range of 310 to 450 °C.

6. A method for preparing the catalyst for HCl oxidation according to any one of claims 1-5, characterized in that the step Comprising: (1) Crushing the alumina hydrate containing iron element to obtain solid powder with an average particle size of 1 to 5 μm, dispersing it in water, stirring and mixing evenly, and then adding an acidic liquid to obtain a slurry support; (2) Mixing the mixed salt solution containing copper element, alkali metal element, rare earth metal element, and optionally other elements with the slurry support in step (1) evenly to obtain a paste, and then spray-drying and calcining to obtain a catalyst for HCl oxidation.

7. The preparation method according to claim 6, characterized in that, For the alumina hydrate containing iron element in step (1), based on the total mass of the alumina hydrate containing iron element, the mass content of iron element is 0.85 ppm to 1.65%; and / or The concentration of the solid powder dispersed in water in step (1) is 10 to 60 wt%; and / or For the acidic liquid in step (1), the acid is selected from at least one of nitric acid, hydrochloric acid, and phosphoric acid; Preferably, the acidic liquid is an aqueous solution of an acid with a concentration of 30 to 60 wt%. Preferably, the mass ratio of the acidic liquid to the solid powder is 0.03 to 0.12:

1.

8. The preparation method according to claim 6, characterized in that, For the mixed salt solution containing copper element, alkali metal element, rare earth metal element, and optionally other elements in step (2), the salt is selected from at least one of nitrates, chlorides, and carbonates; Preferably, in the mixed salt solution, the concentration of copper salt is 5-12 wt%; the concentration of alkali metal element salt is 0.5-6 wt%; the concentration of rare earth metal element salt is 1-12 wt%; the concentration of other element salts is 0-10 wt%, preferably 0.15-6.5 wt%; and / or The mass ratio of the mixed salt solution containing copper element, alkali metal element, rare earth metal element, and optionally other elements in step (2) to the slurry carrier in step (1) is 0.2-3:

1.

9. The preparation method according to claim 6, characterized in that, The calcination in step (2) is carried out in an inert atmosphere containing oxygen; For the calcination, the temperature is 400-650 °C and the time is 0.5-8 h; Preferably, in the inert atmosphere, the volume content of oxygen is 1-30%; the inert atmosphere is selected from at least one of nitrogen and helium, preferably nitrogen.

10. Use of the catalyst for HCl oxidation according to any one of claims 1-5 or the catalyst for HCl oxidation prepared by the method according to any one of claims 6-9 in the oxidation of HCl to chlorine.