A method for preparing molybdenum dioxide dichloride based on molybdenum-containing solution

Abstract

The present invention provides a method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution. The technical scheme comprises the following steps: adjusting the pH of the molybdenum-containing solution to 7.5-9.0 using a pH regulator to obtain a treated molybdenum-containing solution; adding a calcium source to the treated molybdenum-containing solution at a molar ratio of molybdenum to calcium source of 1:1.5-2.0, stirring, and solid-liquid separation to obtain a molybdenum-containing precipitate; mixing the molybdenum-containing precipitate with a chlorinating agent at a molar ratio of molybdenum to chlorinating agent of 1:1-4 to obtain a chlorination reaction product; placing the chlorination reaction product in a reaction apparatus, introducing a protective atmosphere, and reacting at 150-180°C for 1-3 hours to produce molybdenum dioxide dichloride gas; and condensing the molybdenum dioxide dichloride gas at 0-50°C to obtain molybdenum dioxide dichloride based on the molybdenum-containing solution. This method features a simple process, environmental friendliness, high safety, and low energy consumption. The prepared molybdenum dioxide dichloride based on the molybdenum-containing solution is of high purity.

Description

Technical Field

[0001] The present invention belongs to the technical field of molybdenum dioxide dichloride, and specifically relates to a method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution. Background Art

[0002] Molybdenum dioxide dichloride, with the chemical formula MoO2Cl2, appears as pale yellow crystals with a sublimation temperature of 156°C. It is highly hygroscopic and easily hydrolyzed. Currently, it is commonly used as a molybdenum source material for chemical vapor deposition (CVD) to deposit molybdenum thin films, which can be used as diffusion barriers, electrodes, interconnects, and other devices. Due to its high stability and suitability for mass production, molybdenum dioxide dichloride is widely used in the semiconductor industry, including memory chips, logic chips, and catalysts.

[0003] The purity of molybdenum dioxide dichloride currently sold on the market typically ranges from 98% to 99.5%. The process for preparing molybdenum dioxide dichloride generally uses precursors such as industrial-grade molybdenum dioxide or molybdenum trioxide as raw materials, which is subject to significant raw material restrictions and a limited range of applications. Industrial-grade molybdenum dioxide or molybdenum trioxide must undergo a process of "molybdate solution purification - ammonium molybdate solution - acid precipitation and crystallization - ammonium tetramolybdate - (reduction) roasting." For example, the document (Feng Xingliang, Research on a Process for Recycling Low-Grade Molybdenum Tailings to Prepare Molybdenum Trioxide [D], Tianjin University, 2007) discloses a process for recycling low-grade molybdenum tailings to prepare molybdenum trioxide. This process uses low-grade molybdenum tailings as raw material. After roasting and water leaching, a molybdate solution is obtained. The molybdate solution is enriched and impurities are removed using an ion exchange resin. After desorption with an NH4Cl solution, a pure ammonium molybdate solution is obtained. The ammonium molybdate solution is then subjected to acid precipitation and crystallization to obtain ammonium tetramolybdate. The ammonium tetramolybdate is then simply roasted and decomposed to obtain molybdenum trioxide. This process is not only complex but also produces a large amount of ammonia nitrogen wastewater and waste gas.

[0004] The patented technology of "Production of MoO2Cl2" (CN116529206A) charges MoO2 into a reaction vessel, where the MoO2 in the reaction vessel reacts with the supplied Cl2 to generate gaseous MoO2Cl2, which is then transferred to a receiving vessel where solid MoO2Cl2 is produced at a temperature below 160°C. However, this technology uses chlorine as a chlorinating agent, which is highly corrosive and toxic, pollutes the environment, and has low safety.

[0005] The patented technology of "A novel preparation method of molybdenum dioxide dichloride" (CN117208963A) uses molybdenum trioxide, activated carbon and chlorine as reaction raw materials. The molybdenum trioxide and activated carbon are mixed in a certain proportion, placed in a tubular reactor and heated to 200-400°C, and then an excess of dry chlorine is introduced to react to obtain MoO2Cl2 gas; the MoO2Cl2 gas is introduced into an adsorption tower filled with an adsorbent containing high-temperature resistant metal impurities at a volume percentage of 1-30%, the adsorbent adsorbs the metal impurities at 180-200°C, and the MoO2Cl2 is collected in a cooling chamber; although this technology uses activated carbon to increase the activity of the chlorination reaction, the reaction temperature still needs to be 200-400°C, and the purity of the initially obtained MoO2Cl2 gas is not high. The metal impurities need to be removed by passing through the adsorption tower at a high temperature of 180-200°C, which consumes a lot of energy.

[0006] In summary, the existing methods for preparing molybdenum dioxide dichloride have the disadvantages of complex process flow, environmental pollution, low safety, high energy consumption, and low product purity. Summary of the Invention

[0007] The present invention aims to overcome the defects of the prior art and aims to provide a method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution with simple process, environmental friendliness, high safety and low energy consumption. The molybdenum dioxide dichloride based on a molybdenum-containing solution prepared by the method has high purity.

[0008] To achieve the above object, the specific steps of the technical solution adopted by the present invention are:

[0009] Step 1: Preparation of molybdenum-containing precipitate

[0010] A pH regulator is added to the molybdenum-containing solution to adjust the pH value to 7.5-9.0 to obtain a treated molybdenum-containing solution; according to a molar ratio of molybdenum to a calcium source in the treated molybdenum-containing solution of 1:1.5-2.0, the calcium source is added to the treated molybdenum-containing solution, stirred at 30-60° C. for 30-100 minutes, and solid-liquid separation is performed to obtain a molybdenum-containing precipitate.

[0011] The chemical composition of the molybdenum-containing solution is: Mo≥2000 mg / L, Al is 100-1000 mg / L, P is 1000-5000 mg / L, Si is 300-5000 mg / L, and V is 20-200 mg / L.

[0012] Step 2: Preparation of molybdenum dioxide dichloride

[0013] 2.1. According to the molar ratio of molybdenum in the molybdenum-containing precipitate to the chlorinating agent being 1:1-4, the molybdenum-containing precipitate is mixed with the chlorinating agent to obtain a chlorination reactant.

[0014] 2.2. The chlorinated reactant is placed in a reaction apparatus, introduced into a protective atmosphere, and reacted at 150-180° C. for 1-3 hours to produce molybdenum dioxide dichloride gas; the molybdenum dioxide dichloride gas is then condensed at 0-50° C. to produce molybdenum dioxide dichloride based on a molybdenum-containing solution.

[0015] The valence state of molybdenum in the molybdenum-containing solution is hexavalent, and the molybdenum ions exist in the form of molybdate ions.

[0016] The pH adjuster is a hydrochloric acid solution or a sodium hydroxide solution.

[0017] The calcium source is one of calcium chloride, calcium hydroxide and calcium oxide.

[0018] The stirring speed is 400-800 r / min.

[0019] The chlorinating agent is anhydrous aluminum chloride or a mixture of anhydrous aluminum chloride and sodium chloride.

[0020] The amount of the protective atmosphere introduced is 150 to 300 L / h.

[0021] The protective atmosphere is nitrogen or argon.

[0022] Compared with the prior art, the present invention has the following positive effects:

[0023] 1. The chlorination reaction temperature in the present invention is 150°C to 180°C, and impurity elements such as calcium, sodium, silicon, and phosphorus in the raw materials are not easily volatile below 300°C. During the chlorination reaction, when molybdenum volatilizes in the form of dichlorodioxide and condenses to obtain dichlorodioxide solid, other impurities do not appear in the dichloromolybdenum dioxide based on the molybdenum-containing solution. The obtained dichloromolybdenum dioxide based on the molybdenum-containing solution has a purity of ≥99%. The present invention realizes the enrichment and purification of the molybdenum-containing solution and the preparation of dichloromolybdenum dioxide in one step. In the process of preparing the dichloromolybdenum dioxide based on the molybdenum-containing solution, efficient separation of molybdenum and impurities can be completed simultaneously. Compared with the existing method for preparing dichloromolybdenum dioxide using industrial-grade molybdenum dioxide or molybdenum trioxide as the molybdenum source, the present invention does not require "molybdate solution purification-ammonium molybdate solution-acid precipitation crystallization-ammonium tetramolybdate-(reduction) roasting" or additional dichloromolybdenum dioxide purification process, so the process is simple, does not produce ammonia nitrogen wastewater and waste gas, and is environmentally friendly.

[0024] 2. The present invention uses anhydrous aluminum chloride or a mixture of anhydrous aluminum chloride and sodium chloride as a chlorinating agent, which avoids the highly corrosive and highly toxic effects of chlorine, reduces potential risks to humans and the environment, and has higher safety. Compared with the prior art that uses chlorine as a chlorinating agent and roasts the molybdenum source at 200-400°C, the Gibbs free energy of the reaction is lower and it is easier to react with the molybdenum source. Therefore, the prepared molybdenum dioxide dichloride based on the molybdenum-containing solution has a lower reaction temperature and low energy consumption.

[0025] 3. The present invention adopts low-temperature molten salt chlorination-distillation technology to achieve good molybdenum impurity separation effect, the product contains low impurity ion content, and the final obtained molybdenum dioxide dichloride based on the molybdenum-containing solution has no impurity peaks in the X-ray diffraction spectrum, and the product purity is high.

[0026] Therefore, the present invention has the characteristics of simple process, environmental friendliness, high safety and low energy consumption, and the prepared molybdenum dioxide dichloride based on the molybdenum-containing solution has high purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention discloses an X-ray diffraction pattern of molybdenum dioxide dichloride prepared based on a molybdenum-containing solution after detection. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, which does not limit the scope of protection thereof.

[0029] A method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution. The preparation method of this specific embodiment:

[0030] Step 1: Preparation of molybdenum-containing precipitate

[0031] A pH regulator is added to the molybdenum-containing solution to adjust the pH value to 7.5-9.0 to obtain a treated molybdenum-containing solution; according to a molar ratio of molybdenum to a calcium source in the treated molybdenum-containing solution of 1:1.5-2.0, the calcium source is added to the treated molybdenum-containing solution, stirred at 30-60° C. for 30-100 minutes, and solid-liquid separation is performed to obtain a molybdenum-containing precipitate.

[0032] The chemical composition of the molybdenum-containing solution is: Mo≥2000 mg / L, Al is 100-1000 mg / L, P is 1000-5000 mg / L, Si is 300-5000 mg / L, and V is 20-200 mg / L.

[0033] Step 2: Preparation of molybdenum dioxide dichloride

[0034] 2.1. According to the molar ratio of molybdenum in the molybdenum-containing precipitate to the chlorinating agent being 1:1-4, the molybdenum-containing precipitate is mixed with the chlorinating agent to obtain a chlorination reactant.

[0035] 2.2. The chlorinated reactant is placed in a reaction apparatus, introduced into a protective atmosphere, and reacted at 150-180° C. for 1-3 hours to produce molybdenum dioxide dichloride gas; the molybdenum dioxide dichloride gas is then condensed at 0-50° C. to produce molybdenum dioxide dichloride based on a molybdenum-containing solution.

[0036] The valence state of molybdenum in the molybdenum-containing solution is hexavalent, and the molybdenum ions exist in the form of molybdate ions.

[0037] The pH adjuster is a hydrochloric acid solution or a sodium hydroxide solution.

[0038] The calcium source is one of calcium chloride, calcium hydroxide and calcium oxide.

[0039] The stirring speed is 400-800 r / min.

[0040] The chlorinating agent is anhydrous aluminum chloride or a mixture of anhydrous aluminum chloride and sodium chloride.

[0041] The amount of the protective atmosphere introduced is 150 to 300 L / h.

[0042] The protective atmosphere is nitrogen or argon.

[0043] In this specific implementation mode:

[0044] The valence state of molybdenum in the molybdenum-containing solution is hexavalent, and the molybdenum ions exist in the form of molybdate ions.

[0045] The details will not be described in detail in the embodiments.

[0046] Example 1

[0047] A method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution. The steps of the preparation method described in this embodiment are:

[0048] Step 1: Preparation of molybdenum-containing precipitate

[0049] A pH regulator was added to the molybdenum-containing solution to adjust the pH value to 7.5 to obtain a treated molybdenum-containing solution; according to a molar ratio of molybdenum to calcium source in the treated molybdenum-containing solution of 1:1.5, the calcium source was added to the treated molybdenum-containing solution, stirred at 30° C. for 30 minutes, and solid-liquid separation was performed to obtain a molybdenum-containing precipitate.

[0050] The chemical composition of the molybdenum-containing solution is: Mo is 2140 mg / L, Al is 108 mg / L, P is 258 mg / L, Si is 311 mg / L, and V is 20 mg / L.

[0051] Step 2: Preparation of molybdenum dioxide dichloride

[0052] 2.1. According to the molar ratio of molybdenum in the molybdenum-containing precipitate to the chlorinating agent being 1:1, the molybdenum-containing precipitate and the chlorinating agent are mixed to obtain a chlorination reactant.

[0053] 2.2. The chlorinated reactant is placed in a reaction apparatus, introduced into a protective atmosphere, and reacted at 150° C. for 1 hour to produce molybdenum dioxide dichloride gas; the molybdenum dioxide dichloride gas is then condensed at 0° C. to produce molybdenum dioxide dichloride based on a molybdenum-containing solution.

[0054] The pH adjuster is a hydrochloric acid solution.

[0055] The calcium source is calcium chloride.

[0056] The stirring speed is 400 r / min.

[0057] The chlorinating agent is anhydrous aluminum chloride.

[0058] The amount of the protective atmosphere introduced was 150 L / h.

[0059] The protective atmosphere is nitrogen.

[0060] Example 2

[0061] A method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution. The steps of the preparation method described in this embodiment are:

[0062] Step 1: Preparation of molybdenum-containing precipitate

[0063] A pH regulator was added to the molybdenum-containing solution to adjust the pH value to 7.8 to obtain a treated molybdenum-containing solution; according to a molar ratio of molybdenum to calcium source in the treated molybdenum-containing solution of 1:1.6, the calcium source was added to the treated molybdenum-containing solution, stirred at 35° C. for 45 minutes, and solid-liquid separation was performed to obtain a molybdenum-containing precipitate.

[0064] The chemical composition of the molybdenum-containing solution is: Mo is 3048 mg / L, Al is 288 mg / L, P is 1070 mg / L, Si is 1847 mg / L, and V is 64 mg / L.

[0065] Step 2: Preparation of molybdenum dioxide dichloride

[0066] 2.1. According to the molar ratio of molybdenum in the molybdenum-containing precipitate to the chlorinating agent being 1:1.6, the molybdenum-containing precipitate is mixed with the chlorinating agent to obtain a chlorination reactant.

[0067] 2.2. The chlorinated reactant is placed in a reaction apparatus, introduced into a protective atmosphere, and reacted at 155° C. for 1.5 hours to produce molybdenum dioxide dichloride gas; the molybdenum dioxide dichloride gas is then condensed at 10° C. to produce molybdenum dioxide dichloride based on a molybdenum-containing solution.

[0068] The pH regulator is sodium hydroxide solution.

[0069] The calcium source is calcium hydroxide.

[0070] The stirring speed is 480 / min.

[0071] The chlorinating agent is a mixture of anhydrous aluminum chloride and sodium chloride.

[0072] The amount of the protective atmosphere introduced was 180 L / h.

[0073] The protective atmosphere is argon.

[0074] Example 3

[0075] A method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution. The steps of the preparation method described in this embodiment are:

[0076] Step 1: Preparation of molybdenum-containing precipitate

[0077] A pH regulator was added to the molybdenum-containing solution to adjust the pH to 8.0 to obtain a treated molybdenum-containing solution; the calcium source was added to the treated molybdenum-containing solution according to a molar ratio of molybdenum to calcium source of 1:1.7, and the mixture was stirred at 42° C. for 60 minutes, and solid-liquid separation was performed to obtain a molybdenum-containing precipitate.

[0078] The chemical composition of the molybdenum-containing solution is: Mo is 4894 mg / L, Al is 419 mg / L, P is 2863 mg / L, Si is 2539 mg / L, and V is 121 mg / L.

[0079] Step 2: Preparation of molybdenum dioxide dichloride

[0080] 2.1. According to the molar ratio of molybdenum in the molybdenum-containing precipitate to the chlorinating agent being 1:2.2, the molybdenum-containing precipitate is mixed with the chlorinating agent to obtain a chlorination reactant.

[0081] 2.2. The chlorinated reactant is placed in a reaction apparatus, introduced into a protective atmosphere, and reacted at 162° C. for 2 h to produce molybdenum dioxide dichloride gas; the molybdenum dioxide dichloride gas is then condensed at 20° C. to produce molybdenum dioxide dichloride based on a molybdenum-containing solution.

[0082] The pH adjuster is a hydrochloric acid solution.

[0083] The calcium source is calcium oxide.

[0084] The stirring speed is 550 r / min.

[0085] The chlorinating agent is anhydrous aluminum chloride.

[0086] The amount of the protective atmosphere introduced was 200 L / h.

[0087] The protective atmosphere is nitrogen.

[0088] Example 4

[0089] A method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution. The steps of the preparation method described in this embodiment are:

[0090] Step 1: Preparation of molybdenum-containing precipitate

[0091] A pH regulator was added to the molybdenum-containing solution to adjust the pH to 8.4 to obtain a treated molybdenum-containing solution; according to a molar ratio of molybdenum to calcium source in the treated molybdenum-containing solution of 1:1.8, the calcium source was added to the treated molybdenum-containing solution, stirred at 50° C. for 75 minutes, and solid-liquid separation was performed to obtain a molybdenum-containing precipitate.

[0092] The chemical composition of the molybdenum-containing solution is: Mo is 5783 mg / L, Al is 583 mg / L, P is 3482 mg / L, Si is 3374 mg / L, and V is 137 mg / L.

[0093] Step 2: Preparation of molybdenum dioxide dichloride

[0094] 2.1. According to the molar ratio of molybdenum in the molybdenum-containing precipitate to the chlorinating agent being 1:2.8, the molybdenum-containing precipitate is mixed with the chlorinating agent to obtain a chlorination reactant.

[0095] 2.2. The chlorinated reactant is placed in a reaction apparatus, introduced into a protective atmosphere, and reacted at 170° C. for 2.5 hours to produce molybdenum dioxide dichloride gas; the molybdenum dioxide dichloride gas is then condensed at 30° C. to produce molybdenum dioxide dichloride based on a molybdenum-containing solution.

[0096] The pH regulator is sodium hydroxide solution.

[0097] The calcium source is calcium chloride.

[0098] The stirring speed is 650 r / min.

[0099] The chlorinating agent is a mixture of anhydrous aluminum chloride and sodium chloride.

[0100] The amount of the protective atmosphere introduced was 250 L / h.

[0101] The protective atmosphere is argon.

[0102] Example 5

[0103] A method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution. The steps of the preparation method described in this embodiment are:

[0104] Step 1: Preparation of molybdenum-containing precipitate

[0105] A pH regulator was added to the molybdenum-containing solution to adjust the pH to 8.7 to obtain a treated molybdenum-containing solution; according to a molar ratio of molybdenum to calcium source in the treated molybdenum-containing solution of 1:1.9, the calcium source was added to the treated molybdenum-containing solution, stirred at 55° C. for 90 minutes, and solid-liquid separation was performed to obtain a molybdenum-containing precipitate.

[0106] The chemical composition of the molybdenum-containing solution is: Mo is 6538 mg / L, Al is 820 mg / L, P is 4567 mg / L, Si is 4150 mg / L, and V is 164 mg / L.

[0107] Step 2: Preparation of molybdenum dioxide dichloride

[0108] 2.1. According to the molar ratio of molybdenum in the molybdenum-containing precipitate to the chlorinating agent being 1:3.4, the molybdenum-containing precipitate is mixed with the chlorinating agent to obtain a chlorination reactant.

[0109] 2.2. The chlorinated reactant is placed in a reaction apparatus, introduced into a protective atmosphere, and reacted at 175° C. for 2.8 h to produce molybdenum dioxide dichloride gas; the molybdenum dioxide dichloride gas is then condensed at 40° C. to produce molybdenum dioxide dichloride based on a molybdenum-containing solution.

[0110] The pH adjuster is a hydrochloric acid solution.

[0111] The calcium source is calcium hydroxide.

[0112] The stirring speed is 720 r / min.

[0113] The chlorinating agent is anhydrous aluminum chloride.

[0114] The amount of the protective atmosphere introduced was 270 L / h.

[0115] The protective atmosphere is nitrogen.

[0116] Example 6

[0117] A method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution. The steps of the preparation method described in this embodiment are:

[0118] Step 1: Preparation of molybdenum-containing precipitate

[0119] A pH regulator was added to the molybdenum-containing solution to adjust the pH value to 9.0 to obtain a treated molybdenum-containing solution; the calcium source was added to the treated molybdenum-containing solution according to a molar ratio of molybdenum to calcium source of 1:2.0 in the treated molybdenum-containing solution, and the mixture was stirred at 60° C. for 100 minutes, and solid-liquid separation was performed to obtain a molybdenum-containing precipitate.

[0120] The chemical composition of the molybdenum-containing solution is: Mo is 7145 mg / L, Al is 988 mg / L, P is 4990 mg / L, Si is 4897 mg / L, and V is 195 mg / L.

[0121] Step 2: Preparation of molybdenum dioxide dichloride

[0122] 2.1. According to the molar ratio of molybdenum in the molybdenum-containing precipitate to the chlorinating agent being 1:4, the molybdenum-containing precipitate and the chlorinating agent are mixed to obtain a chlorination reactant.

[0123] 2.2. The chlorinated reactant is placed in a reaction apparatus, introduced into a protective atmosphere, and reacted at 180° C. for 3 h to produce molybdenum dioxide dichloride gas; the molybdenum dioxide dichloride gas is then condensed at 50° C. to obtain molybdenum dioxide dichloride based on the molybdenum-containing solution.

[0124] The pH regulator is sodium hydroxide solution.

[0125] The calcium source is calcium oxide.

[0126] The stirring speed is 800 r / min.

[0127] The chlorinating agent is a mixture of anhydrous aluminum chloride and sodium chloride.

[0128] The amount of the protective atmosphere introduced was 300 L / h.

[0129] The protective atmosphere is argon.

[0130] Compared with the prior art, this embodiment has the following positive effects:

[0131] 1. The chlorination reaction temperature in this embodiment is 150°C to 180°C, and impurity elements such as calcium, sodium, silicon, and phosphorus in the raw materials are not easily volatile below 300°C. During the chlorination reaction, when molybdenum volatilizes in the form of dichlorodioxide and condenses to obtain dichlorodioxide solid, other impurities do not appear in the dichloromolybdenum dioxide based on the molybdenum-containing solution. The obtained dichloromolybdenum dioxide based on the molybdenum-containing solution has a purity of ≥99%. This embodiment achieves the enrichment and purification of the molybdenum-containing solution and the preparation of dichloromolybdenum dioxide in one step. In the process of preparing the dichloromolybdenum dioxide based on the molybdenum-containing solution, efficient separation of molybdenum and impurities can be completed simultaneously. Compared with the existing method for preparing dichloromolybdenum dioxide using industrial-grade molybdenum dioxide or molybdenum trioxide as the molybdenum source, this embodiment does not require "molybdate solution purification-ammonium molybdate solution-acid precipitation crystallization-ammonium tetramolybdate-(reduction) roasting" or additional dichloromolybdenum dioxide purification process, so the process is simple, does not produce ammonia nitrogen wastewater and waste gas, and is environmentally friendly.

[0132] 2. This specific embodiment uses anhydrous aluminum chloride or a mixture of anhydrous aluminum chloride and sodium chloride as a chlorinating agent, which avoids the highly corrosive and highly toxic effects of chlorine, reduces potential risks to humans and the environment, and has higher safety. Compared with the prior art that uses chlorine as a chlorinating agent and roasts the molybdenum source at 200-400°C, the Gibbs free energy of the reaction is lower and it is easier to react with the molybdenum source. Therefore, the prepared molybdenum dioxide dichloride based on the molybdenum-containing solution has a lower reaction temperature and low energy consumption.

[0133] 3. This specific embodiment uses low-temperature molten salt chlorination-distillation technology to achieve good molybdenum impurity separation effect. The prepared molybdenum dioxide dichloride based on the molybdenum-containing solution is shown in the attached figure. Figure 1 The X-ray diffraction pattern of molybdenum dioxide dichloride based on molybdenum-containing solution prepared in Example 2 after detection. Although the final product of Example 2 is MoO2Cl2, due to the special properties of MoO2Cl2, it is very easy to absorb water after contact with air. Due to the limited existing detection equipment, it is difficult to achieve vacuum detection throughout the process. Figure 1 The substance detected by the X-ray diffractometer shown is MoO2Cl2·H2O. It can be seen that Figure 1 No additional impurity peaks were observed in the detected X-ray diffraction pattern of MoO2Cl2·H2O, indicating that the molybdenum dioxide dichloride prepared in Example 2 based on the molybdenum-containing solution was of high purity. Therefore, the molybdenum dioxide dichloride prepared in this embodiment based on the molybdenum-containing solution had a low content of impurity ions, and the X-ray diffraction pattern of the molybdenum dioxide dichloride finally prepared based on the molybdenum-containing solution had no impurity peaks, indicating that the product was of high purity.

[0134] Therefore, this specific embodiment has the characteristics of simple process, environmental friendliness, high safety and low energy consumption, and the prepared molybdenum dioxide dichloride based on the molybdenum-containing solution has high purity.

Claims

1. A method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution, characterized in that The specific steps of the preparation method are: Step 1: Preparation of molybdenum-containing precipitate Adding a pH regulator to the molybdenum-containing solution to adjust the pH to 7.5-9.0 to obtain a treated molybdenum-containing solution; adding the calcium source to the treated molybdenum-containing solution according to a molar ratio of molybdenum to a calcium source of 1:1.5-2.0, stirring at 30-60° C. for 30-100 minutes, and performing solid-liquid separation to obtain a molybdenum-containing precipitate; The chemical composition of the molybdenum-containing solution is: Mo ≥ 2000 mg / L, Al 100-1000 mg / L, P 1000-5000 mg / L, Si 300-5000 mg / L, V 20-200 mg / L; Step 2: Preparation of molybdenum dioxide dichloride 2.

1. Mixing the molybdenum-containing precipitate with the chlorinating agent in a molar ratio of molybdenum in the molybdenum-containing precipitate to the chlorinating agent in a range of 1:1 to 4 to obtain a chlorination reactant; 2.

2. The chlorinated reactant is placed in a reaction apparatus, introduced into a protective atmosphere, and reacted at 150-180° C. for 1-3 hours to produce molybdenum dioxide dichloride gas; the molybdenum dioxide dichloride gas is then condensed at 0-50° C. to produce molybdenum dioxide dichloride based on a molybdenum-containing solution; The valence state of molybdenum in the molybdenum-containing solution is hexavalent, and the molybdenum ions exist in the form of molybdate ions; The chlorinating agent is anhydrous aluminum chloride or a mixture of anhydrous aluminum chloride and sodium chloride.

2. The method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution according to claim 1, wherein The pH adjuster is a hydrochloric acid solution or a sodium hydroxide solution.

3. The method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution according to claim 1, wherein The calcium source is one of calcium chloride, calcium hydroxide and calcium oxide.

4. The method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution according to claim 1, wherein The stirring speed is 400-800 r / min.

5. The method for preparing molybdenum dioxide dichloride based on molybdenum-containing solution according to claim 1, wherein The amount of the protective atmosphere introduced is 150-300 L / h.

6. The method for preparing molybdenum dioxide dichloride based on a molybdenum-containing solution according to claim 1, wherein The protective atmosphere is nitrogen or argon.

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