Extraction method of molybdenum trioxide

Abstract

The invention provides an extraction method of molybdenum trioxide, and belongs to the technical field of extraction metallurgy. The extraction method of molybdenum trioxide provided by the invention comprises the following steps: carrying out vacuum melting on a molybdenum-containing material to obtain a sublimate, and cooling the sublimate to obtain molybdenum trioxide, the molybdenum content in the molybdenum-containing material is 37.42 to 46.31 wt%, and the oxygen content in the molybdenum-containing material is 30.74 to 38.13 wt%; the temperature of vacuum melting ranges from 880 DEG C to 1200 DEG C, and the vacuum degree ranges from 0.47 Pa to 10 Pa; the cooling rate of the cooling is 5-10 DEG C / min. According to the method, the molybdenum-containing material is subjected to vacuum melting, molybdate in the molybdenum-containing material is decomposed to obtain molybdenum trioxide, original molybdenum trioxide of the molybdenum-containing material is sublimated under the high-temperature condition, high-purity molybdenum trioxide is obtained through cooling, and the extraction efficiency of molybdenum trioxide is effectively improved; and the extraction method is simple, the low-grade molybdenum-containing material is used as the raw material, the extraction cost is lower, and no pollution is caused to the environment.

Description

Technical Field

[0001] The invention belongs to the technical field of extraction metallurgy, and in particular relates to a method for extracting molybdenum trioxide. Background Art

[0002] Molybdenum trioxide is an inorganic compound with many uses, such as: used as a catalyst in the petroleum industry, as a raw material in the metallurgical industry, as a catalyst in the chemical industry, as a raw material for preparing metallic molybdenum and molybdenum compounds, as a component of pigments and enamel glazes, as a combustion-supporting and smoke-suppressing agent, etc. High-purity molybdenum trioxide has long been a necessary intermediate material for the preparation of metallic molybdenum powder, molybdenum-containing high-temperature alloys, catalysts, pigments and smoke suppressants.

[0003] In the prior art, the methods for extracting molybdenum trioxide from molybdenum roasted sand as raw material are mainly pyrolysis and wet extraction. The pyrolysis method is to directly roast molybdenum roasted sand with a high content of molybdenum trioxide under normal pressure to achieve the purpose of extracting molybdenum trioxide; the defect of this method is that it has high requirements for the taste of molybdenum roasted sand. The wet method mainly uses some solvents to extract molybdenum trioxide from molybdenum roasted sand, and obtains molybdenum trioxide after filtering and drying; this method has the defects of high loss rate and inability to extract molybdenum trioxide efficiently and quickly. Summary of the invention

[0004] The purpose of the present invention is to provide a method for extracting molybdenum trioxide. The present invention uses a molybdenum-containing material with a molybdenum content of 37.42 to 46.31 wt % as a raw material to extract molybdenum trioxide, and the preparation cost is lower. The extraction method of the present invention is simple, has a low loss rate, is environmentally friendly, and reduces the extraction cost.

[0005] In order to achieve the purpose of the present invention, the present invention provides the following technical solutions:

[0006] A method for extracting molybdenum trioxide comprises the following steps:

[0007] The molybdenum-containing material is subjected to vacuum melting to obtain a sublimate, and then cooled to obtain the molybdenum trioxide; the molybdenum content of the molybdenum-containing material is 37.42-46.31wt%, and the oxygen content is 30.74-38.13wt%;

[0008] The vacuum melting temperature is 880-1200°C and the vacuum degree is 0.47-10Pa;

[0009] The cooling rate is 5-10°C / min.

[0010] Preferably, the molybdenum-containing material includes one or more of molybdenum roasted sand, ferric molybdate, ferrous molybdate and calcium molybdate.

[0011] Preferably, the element composition of the molybdenum roasted sand includes: O 30.74-38.13wt%, Mo 37.42-46.31wt%, Fe 4.36-10.68wt%, Si 5.90-7.06wt%, Cu 2.04-2.13wt%, Ca 1.33-1.36wt% and Al 0.95-0.99wt%.

[0012] Preferably, the vacuum melting time is 1 to 4 hours.

[0013] Preferably, the heating rate to the temperature required for vacuum melting is 20-30° C. / min.

[0014] Preferably, the apparatus used for vacuum melting is a vertical vacuum furnace.

[0015] Preferably, the purity of the molybdenum trioxide is 98.67-99.68%.

[0016] Preferably, the cooling is performed under a vacuum atmosphere.

[0017] The present invention provides a method for extracting molybdenum trioxide, comprising the following steps: vacuum melting a molybdenum-containing material, and cooling to obtain the molybdenum trioxide; the molybdenum content in the molybdenum-containing material is 37.42-46.31wt%, and the oxygen content is 30.74-38.13wt%; the temperature of the vacuum melting is 880-1200°C, and the vacuum degree is 5-10Pa; the cooling rate of the cooling is 5-10°C / min. The present invention vacuum melts the molybdenum-containing material, and by controlling the vacuum melting temperature to 880-1200°C and the vacuum degree to 5-10Pa, the extracted molybdenum trioxide is not only the original molybdenum trioxide in the simple molybdenum roasted sand, but also more molybdenum trioxide produced by the decomposition of molybdate in the molybdenum roasted sand, and finally high-purity molybdenum trioxide is obtained after secondary temperature-controlled cooling, which effectively improves the extraction efficiency of molybdenum trioxide; and the extraction method of the present invention is simple, uses low-grade molybdenum-containing materials as raw materials, has lower extraction costs, and is pollution-free to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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.

[0019] Figure 1 This is a condensation diagram of molybdenum trioxide obtained in Example 1 of the present invention. Figure 1 From left to right in the figure are the crucible wall and the crucible cover;

[0020] Figure 2 This is a condensation diagram of molybdenum trioxide obtained in Example 2 of the present invention. Figure 2 From left to right in the figure are the crucible wall and the crucible cover;

[0021] Figure 3 This is a condensation diagram of molybdenum trioxide obtained in Comparative Example 1 of the present invention. Figure 3 From left to right in the figure are the crucible wall and the crucible cover;

[0022] Figure 4 The XRD spectra of molybdenum trioxide obtained in Examples 1 and 2 of the present invention are shown. DETAILED DESCRIPTION

[0023] The present invention provides a method for extracting molybdenum trioxide, comprising the following steps:

[0024] The molybdenum-containing material is subjected to vacuum melting to obtain a sublimate, and then cooled to obtain the molybdenum trioxide; the molybdenum content of the molybdenum-containing material is 37.42-46.31wt%, and the oxygen content is 30.74-38.13wt%;

[0025] The temperature of the vacuum melting is 880-1200° C., and the vacuum degree is 0.47-10 Pa; the cooling rate of the cooling is 5-10° C. / min.

[0026] In the present invention, unless otherwise specified, all raw materials are commercially available products well known to those skilled in the art.

[0027] In the present invention, the molybdenum content in the molybdenum-containing material is 37.42-46.31wt%, and in a specific embodiment, it can be 38wt%, 42 or 45wt%; the oxygen content is 30.74-38.13wt%, and in a specific embodiment, it can be 33wt%, 35wt% or 37wt%.

[0028] In the present invention, the molybdenum-containing material includes one or more of molybdenum roasted sand, ferric molybdate, ferrous molybdate and calcium molybdate. In a specific embodiment, it can be molybdenum roasted sand; the element composition of the molybdenum roasted sand includes: O30.74-38.13wt%, Mo37.42-46.31wt%, Fe 4.36-10.68wt%, Si 5.90-7.06wt%, Cu 2.04-2.13wt%, Ca1.33-1.36wt% and Al 0.95-0.99wt%. In the present invention, the elements in the molybdenum roasted sand exist in the form of Mo2O3, FeMoO4, CuMoO4, CaMoO4, AlH5MoO and SiO2.

[0029] In the present invention, the instrument used for vacuum melting can be a vertical vacuum furnace; the heating rate for heating to the temperature required for vacuum melting can be 20-30°C / min, and in a specific embodiment, it can be 30°C / min, 25°C / min or 28°C / min; the temperature of the vacuum melting can be 880-1200°C, and in a specific embodiment, it can be 980°C, 1000°C, 1050°C, 1100°C or 1180°C; the vacuum degree can be 0.47-10Pa, and in a specific embodiment, it can be 1Pa, 5Pa, 6Pa, 7Pa, 8Pa or 9Pa; the time of vacuum melting can be 1-4h, and in a specific embodiment, it can be 2h, 2.5h, 3h or 3.5h; the cooling rate of the cooling can be 5-10°C / min, and in a specific embodiment, it can be 6°C / min, 7°C / min or 8°C / min; the cooling is carried out in a vacuum atmosphere; the vacuum degree of the vacuum atmosphere is 5-10Pa.

[0030] In the present invention, the purity of the molybdenum trioxide can be 98.67-99.68%, and in a specific embodiment, it can be 98.90%, 99.34% or 99.56%.

[0031] In order to further illustrate the present invention, the extraction method of molybdenum trioxide 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 scope of protection of the present invention.

[0032] Example 1

[0033] Weigh 40g of molybdenum roasted sand (molybdenum content is 37.42wt%) and place it in a corundum crucible, move the crucible to a vacuum furnace, cover the corundum crucible cover, and turn on the vacuum furnace. The temperature control method of the vacuum furnace during vacuum smelting is: heat the temperature to 880°C at a heating rate of 30°C / min, vacuum smelting time is 3h at 880°C and 10Pa, and the vacuum furnace is turned off after the vacuum smelting is completed. After the material is cooled to room temperature at a rate of 10°C / min, the crucible is taken out, and the molybdenum trioxide condensate on the crucible wall and the crucible cover is separated. The mass is 12.39g, and the molybdenum trioxide extraction rate is 44.89%.

[0034] Example 2

[0035] Weigh 40g of molybdenum roasted sand (molybdenum content is 46.31wt%) and place it in a corundum crucible, move the crucible to a vacuum furnace, cover the corundum crucible cover, and turn on the vacuum furnace. The temperature control method of the vacuum furnace during vacuum smelting is: heat the temperature to 1200°C at a heating rate of 30°C / min, vacuum smelting time is 3h at 1200°C and 5Pa, and the vacuum furnace is turned off after the vacuum smelting is completed. After the material is cooled to room temperature at a rate of 10°C / min, the crucible is taken out, and the molybdenum trioxide condensate on the crucible wall and the crucible cover is separated. The mass is 15.61g, and the molybdenum trioxide extraction rate is 56.56%.

[0036] Comparative Example 1

[0037] Weigh 40 g of molybdenum roasted sand (molybdenum content is 46.31 wt%) and place it in a corundum crucible, move the crucible into a vacuum furnace, cover the corundum crucible cover, and turn on the vacuum furnace. The temperature control method of the vacuum furnace during vacuum melting is: heat up to 1300°C at a heating rate of 30°C / min, vacuum melting time is 1h at 1300°C and 10Pa, and the vacuum furnace is turned off after the vacuum melting is completed. After the material is cooled to room temperature at 10°C / min, the crucible is taken out, and it is found that the material is adhered to the crucible, and the condensate is splashed and contaminated, making it difficult to collect.

[0038] Comparative Example 2

[0039] Weigh 20 g of molybdenum roasted sand (molybdenum content is 37.42wt%) and place it in a corundum crucible, move the crucible to a muffle furnace, cover the corundum crucible cover, and turn on the muffle furnace. The temperature control method of the muffle furnace is to increase the temperature to 1200°C at a heating rate of 30°C / min. The roasting time is 6 hours at 1200°C and normal pressure. After the normal pressure roasting is completed, cool to room temperature at 30°C / min and take out the crucible. It was found that no condensate appeared and the quality of the molybdenum roasted sand did not change much.

[0040] Figure 1 This is a condensation diagram of molybdenum trioxide obtained in Example 1 of the present invention. Figure 1 From left to right in the figure are the crucible wall and the crucible cover; Figure 2 This is a condensation diagram of molybdenum trioxide obtained in Example 2 of the present invention. Figure 2 From left to right in the figure are the crucible wall and the crucible cover; Figure 3 This is a condensation diagram of molybdenum trioxide obtained in Comparative Example 1 of the present invention. Figure 3 From left to right in the figure are the crucible wall and the crucible cover; Figure 4 The XRD spectra of molybdenum trioxide obtained in Example 1 and Example 2 of the present invention are shown in FIG. Figures 1 to 4It can be seen that the direct roasting of molybdenum roasted sand under normal pressure to extract molybdenum oxide has high requirements on the grade of the molybdenum roasted sand itself, and generally molybdenum roasted sand with a molybdenum content of 90% is used for the extraction; it is very helpful for molybdenum roasted sand to extract molybdenum trioxide under vacuum. The vacuum degree adopted by the present invention is 5-10pa, and the extraction effect at 1200°C is the best under this vacuum condition. When the temperature exceeds 1300°C, the molybdenum roasted sand will spray and adhere to the corundum crucible. The main reason is that the molybdenum content in the molybdenum roasted sand is too low, and the main molybdenum-containing substance is not molybdenum trioxide, but molybdate. At normal pressure, it is impossible to provide the experimental conditions for the decomposition of molybdate into molybdenum trioxide. Therefore, it is recommended to conduct the experiment of vacuum melting of molybdenum roasted sand to extract molybdenum trioxide at a temperature not exceeding 1300°C.

[0041] 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. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for extracting molybdenum trioxide, characterized in that: The following steps are involved: The molybdenum-containing material is subjected to vacuum melting to obtain a sublimate, and then cooled to obtain the molybdenum trioxide; the molybdenum content of the molybdenum-containing material is 37.42-46.31wt%, and the oxygen content is 30.74-38.13wt%; The vacuum melting temperature is 880-1200°C and the vacuum degree is 0.47-10Pa; The cooling rate is 5-10°C / min.

2. The extraction method according to claim 1, characterized in that The molybdenum-containing material includes one or more of molybdenum roasted sand, ferric molybdate, ferrous molybdate and calcium molybdate.

3. The extraction method according to claim 2, characterized in that The element composition of the molybdenum roasted sand includes: 30.74-38.13wt% of O, 37.42-46.31wt% of Mo, 4.36-10.68wt% of Fe, 5.90-7.06wt% of Si, 2.04-2.13wt% of Cu, 1.33-1.36wt% of Ca and 0.95-0.99wt% of Al.

4. The extraction method according to claim 1, characterized in that The vacuum melting time is 1 to 4 hours.

5. The extraction method according to claim 1, characterized in that The heating rate to the temperature required for vacuum melting is 20-30°C / min.

6. The extraction method according to claim 1, characterized in that The apparatus used for vacuum smelting is a vertical vacuum furnace.

7. The extraction method according to claim 1, characterized in that The purity of the molybdenum trioxide is 98.67-99.68%.

8. The extraction method according to claim 1, characterized in that The cooling is performed in a vacuum atmosphere.

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