A method for extracting molybdenum trioxide

Abstract

The application provides a molybdenum trioxide extraction method, and belongs to the field of extraction metallurgy. The molybdenum trioxide extraction method provided by the application comprises the following steps: vacuum smelting a molybdenum-containing material to obtain sublimates, and cooling the sublimates to obtain the molybdenum trioxide; the molybdenum content in the molybdenum-containing material is 37.42-46.31 wt%, and the oxygen content is 30.74-38.13 wt%; the temperature of the vacuum smelting is 880-1200 DEG C, and the vacuum degree is 0.47-10 Pa; and the cooling rate of the cooling is 5-10 DEG C / min. The molybdenum trioxide is obtained by decomposing molybdate in the molybdenum-containing material through vacuum smelting, and the original molybdenum trioxide in the molybdenum-containing material sublimates under high-temperature conditions to obtain high-purity molybdenum trioxide, thereby effectively improving the extraction efficiency of the molybdenum trioxide; and the extraction method is simple, the low-grade molybdenum-containing material is used as the raw material, the extraction cost is lower, and the environment is not polluted.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of extraction metallurgy, and particularly relates to a method for extracting molybdenum trioxide. BACKGROUND

[0002] Molybdenum trioxide is an inorganic compound, which has various uses, such as being used as a catalyst in the petroleum industry, being used as a raw material in the metallurgical industry, being used as a catalyst in the chemical industry, being used as a raw material for preparing metallic molybdenum and molybdenum compounds, being used as a component of pigments and enamel glaze, and being used as a combustion-supporting smoke-suppressing agent. High-purity molybdenum trioxide has long been an intermediate material necessary for preparing metallic molybdenum powder, molybdenum-containing high-temperature alloy, a catalyst, pigments, and smoke-suppressing agents.

[0003] In the prior art, the method for extracting molybdenum trioxide from molybdenum calcine mainly includes a fire method and a wet method. The fire method is to directly roast molybdenum calcine with high molybdenum trioxide content under normal pressure to extract molybdenum trioxide. The defect of this method is that the molybdenum calcine has a high quality requirement. The wet method is to extract molybdenum trioxide from molybdenum calcine by using a solvent, and then to obtain molybdenum trioxide after filtration and drying. This method has the defects of high loss rate and low efficiency and speed in extracting molybdenum trioxide. SUMMARY

[0004] The application aims to provide a method for extracting molybdenum trioxide. The method uses molybdenum-containing material with a molybdenum content of 37.42-46.31 wt% as a raw material to extract molybdenum trioxide, which has a lower preparation cost. The method is simple, has a low loss rate, and does not pollute the environment, thereby reducing the extraction cost.

[0005] To achieve the object of the application, the application provides the following technical solution.

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

[0007] vacuum smelting the molybdenum-containing material to obtain sublimation, and cooling the sublimation to obtain the molybdenum trioxide; the molybdenum content of the molybdenum-containing material is 37.42-46.31 wt%, and the oxygen content is 30.74-38.13 wt%;

[0008] the temperature of the vacuum smelting is 880-1200℃, and the vacuum degree is 0.47-10 Pa;

[0009] the cooling rate of the cooling is 5-10℃ / min.

[0010] Preferably, the molybdenum-containing material comprises one or more of molybdenum calcine, iron molybdate, ferrous molybdate, and calcium molybdate.

[0011] Preferably, the elemental composition of the molybdenum calcine comprises: 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 time for the vacuum smelting is 1-4h.

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

[0014] Preferably, the instrument used for the vacuum smelting is a vertical vacuum furnace.

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

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

[0017] The present application provides a method for extracting molybdenum trioxide, comprising the following steps: vacuum smelting a molybdenum-containing material to obtain the molybdenum trioxide after cooling; the molybdenum content in the molybdenum-containing material is 37.42-46.31wt%, and the oxygen content is 30.74-38.13wt%; the temperature for the vacuum smelting is 880-1200℃, and the vacuum degree is 5-10Pa; the cooling rate is 5-10℃ / min. The molybdenum trioxide extracted by the present application not only contains the original molybdenum trioxide in the molybdenum calcine, but also contains more molybdenum trioxide produced by the decomposition of molybdate in the molybdenum calcine, and high-purity molybdenum trioxide is obtained after secondary temperature control cooling, thereby effectively improving the extraction efficiency of molybdenum trioxide; and the extraction method of the present application is simple, uses low-grade molybdenum-containing material as raw material, has lower extraction cost, and is pollution-free to the environment. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 The condensed physical picture of the molybdenum trioxide obtained in Example 1 of the present application, Figure 1 from left to right in the figure are the crucible wall and the crucible cover;

[0020] Figure 2 A condensed physical picture of the molybdenum trioxide obtained in Example 2 of the present application, Figure 2 In the figure, the crucible wall and the crucible cover are sequentially arranged from left to right.

[0021] Figure 3 A condensed physical picture of the molybdenum trioxide obtained in Comparative Example 1 of the present application, Figure 3 In the figure, the crucible wall and the crucible cover are sequentially arranged from left to right.

[0022] Figure 4 XRD spectra of the molybdenum trioxide obtained in Example 1 and Example 2 of the present application. DETAILED DESCRIPTION

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

[0024] The molybdenum-containing material is subjected to vacuum smelting to obtain sublimates, and the molybdenum trioxide is obtained after cooling; the molybdenum content in the molybdenum-containing material is 37.42-46.31wt%, and the oxygen content is 30.74-38.13wt%.

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

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

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

[0028] In the present application, the molybdenum-containing material includes one or more of molybdenum calcine, iron molybdate, ferrous molybdate and calcium molybdate, and in specific embodiments, it can be molybdenum calcine; the elemental composition of the molybdenum calcine 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%. In the present application, each element in the molybdenum calcine exists in the form of Mo2O3, FeMoO4, CuMoO4, CaMoO4, AlH5MoO and SiO2.

[0029] In the present application, the instrument used for the vacuum smelting can be a vertical vacuum furnace; the heating rate for heating to the temperature required for the vacuum smelting can be 20-30℃ / min, in particular embodiments, it can be 30℃ / min, 25℃ / min or 28℃ / min; the temperature for the vacuum smelting can be 880-1200℃, in particular embodiments, it can be 980℃, 1000℃, 1050℃, 1100℃ or 1180℃; the vacuum degree can be 0.47-10 Pa, in particular embodiments, it can be 1 Pa, 5 Pa, 6 Pa, 7 Pa, 8 Pa or 9 Pa; the time for the vacuum smelting can be 1-4 h, in particular embodiments, it can be 2 h, 2.5 h, 3 h or 3.5 h; the cooling rate for the cooling can be 5-10℃ / min, in particular embodiments, it can be 6℃ / min, 7℃ / min or 8℃ / min; the cooling is performed under a vacuum atmosphere; the vacuum degree of the vacuum atmosphere is 5-10 Pa.

[0030] In the present application, the purity of the molybdenum trioxide can be 98.67-99.68%, in particular embodiments, it can be 98.90%, 99.34% or 99.56%.

[0031] In order to further illustrate the present application, the extraction method of molybdenum trioxide provided by the present application is described in detail below in combination with the drawings and examples, but they should not be understood as limiting the scope of protection of the present application.

[0032] Example 1

[0033] 40 g of molybdenum calcine (molybdenum content: 37.42 wt%) was weighed and placed in a corundum crucible, the crucible was moved into a vacuum furnace, a corundum crucible cover was placed on it, the vacuum furnace was started, and the temperature control mode of the vacuum furnace during the vacuum smelting was as follows: the temperature was raised to 880℃ at a heating rate of 30℃ / min, the vacuum smelting was performed at 880℃ and 10 Pa for 3 h, after the vacuum smelting was completed, the vacuum furnace was turned off, and after the material was cooled to room temperature at a cooling rate of 10℃ / min, the crucible was taken out, and the molybdenum trioxide condensate on the crucible wall and the crucible cover was separated, the mass was 12.39 g, and the extraction rate of molybdenum trioxide was 44.89%.

[0034] Example 2

[0035] Weigh 40g of molybdenum calcined ore (molybdenum content 46.31wt%) and place it in an alumina crucible. Transfer the crucible to a vacuum furnace, cover it with the alumina crucible lid, and turn on the vacuum furnace. During vacuum melting, the temperature control method of the vacuum furnace is as follows: heat up to 1200℃ at a heating rate of 30℃ / min, and vacuum melt for 3 hours at 1200℃ and 5 Pa. After vacuum melting is completed, turn off the vacuum furnace and wait for the material to cool to room temperature at 10℃ / min. Then, remove the crucible and separate the molybdenum trioxide condensate from the crucible wall and the crucible lid. The mass is 15.61g, and the molybdenum trioxide extraction rate is 56.56%.

[0036] Comparative Example 1

[0037] Weigh 40g of molybdenum calcined sand (molybdenum content 46.31wt%) and place it in an alumina crucible. Transfer the crucible to a vacuum furnace, cover it with the alumina crucible lid, and turn on the vacuum furnace. The temperature control method of the vacuum furnace during vacuum melting is: heat up to 1300℃ at a heating rate of 30℃ / min, and vacuum melt for 1 hour at 1300℃ and 10pa. After vacuum melting is completed, turn off the vacuum furnace. After the material cools to room temperature at 10℃ / min, take out the crucible. It is found that the material sticks to the crucible, and the condensate splashes and becomes contaminated, making it difficult to collect.

[0038] Comparative Example 2

[0039] 20g of molybdenum calcined abrasive (molybdenum content 37.42wt%) was weighed and placed in an alumina crucible. The crucible was then transferred to a muffle furnace, the alumina crucible lid was placed on top, and the muffle furnace was turned on. The temperature of the muffle furnace was controlled to rise to 1200℃ at a rate of 30℃ / min. The calcination time at 1200℃ and atmospheric pressure was 6 hours. After the atmospheric pressure calcination was completed, the crucible was cooled to room temperature at a rate of 30℃ / min and then removed. It was found that no condensate was present and the quality of the molybdenum calcined abrasive did not change significantly.

[0040] Figure 1 This is a photograph of the condensed molybdenum trioxide obtained in Example 1 of the present invention. Figure 1 From left to right: crucible wall and crucible lid; Figure 2 This is a photograph of the condensed molybdenum trioxide obtained in Example 2 of the present invention. Figure 2 From left to right: crucible wall and crucible lid; Figure 3 This is a photograph of the condensed molybdenum trioxide obtained in Comparative Example 1 of this invention. Figure 3 From left to right: crucible wall and crucible lid; Figure 4 The images show the XRD patterns of molybdenum trioxide obtained in Examples 1 and 2 of this invention. Figures 1 to 4It is known that direct roasting of molybdenum calcine to extract molybdenum trioxide under normal pressure requires high grade molybdenum calcine, usually with 90% molybdenum content; vacuum is very helpful for extracting molybdenum trioxide from molybdenum calcine, the vacuum degree used in the invention is 5-10 Pa, and the best extraction effect is achieved at 1200℃ under this vacuum degree, and molybdenum calcine will be splashed and adhere to corundum crucible when the temperature exceeds 1300℃, the main reason is that the molybdenum content in molybdenum calcine is too low, and the main molybdenum-containing substance is molybdate instead of molybdenum trioxide, and normal pressure cannot provide the experimental conditions for the decomposition of molybdate into molybdenum trioxide, so it is suggested that the temperature for vacuum smelting of molybdenum calcine to extract molybdenum trioxide should not exceed 1300℃.

[0041] Although the above embodiments have been described in detail, they are only part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained according to the embodiments without creativity, which are within the protection scope of the present application.

Claims

1. A method for extracting molybdenum trioxide, characterized in that, Includes the following steps: The molybdenum-containing material is vacuum melted to obtain the sublimate, which is then cooled twice under controlled temperature to obtain the molybdenum trioxide; the molybdenum content in the molybdenum-containing material is 37.42~46.31 wt%, and the oxygen content is 30.74~38.13 wt%. The vacuum melting temperature is 1000~1200℃, and the vacuum degree is 0.47~10Pa; The cooling rate is 5~10℃ / min; the molybdenum-containing material is molybdenum calcined sand; the instrument used for vacuum melting is a vertical vacuum furnace; The purity of the molybdenum trioxide is 98.67~99.68%.

2. The extraction method according to claim 1, characterized in that, The elemental composition of the molybdenum calcined 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%.

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

4. The extraction method according to claim 1, characterized in that, The heating rate to the temperature required for vacuum melting is 20~30℃ / min.

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

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