A method for extracting molybdenum from a molybdenum oxide feed material

Abstract

This invention discloses a method for extracting molybdenum from molybdenum oxide raw materials, comprising: mixing the molybdenum oxide raw materials with a certain proportion of leaching agent for leaching to obtain a first leaching solution for later use; removing impurities from the first leaching solution through resin or extractant to obtain a molybdenum-containing purified solution; adding a control agent to the molybdenum-containing purified solution to obtain a precursor solution; and placing the precursor solution in an autoclave for heating and decomposition to obtain the final product. The process of this invention can prepare molybdenum dioxide products in a short time, with simple steps and low economic cost, and avoids the introduction of ammonia nitrogen reagents throughout the process, thus preventing the generation of ammonia nitrogen waste pollutants. The molybdenum leaching rate during the leaching process and the molybdenum precipitation rate during the product preparation process of this invention exceed 99.5%.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically relating to a method for extracting molybdenum from molybdenum oxide raw materials. Background Technology

[0002] In current molybdenum metallurgical processes, the traditional method for extracting molybdenum from molybdenite or molybdenum-containing spent catalysts to produce qualified molybdenum products involves hydrometallurgical processes ("oxidative roasting-ammonia leaching" or "oxygen pressure boiling-ammonia dissolution") to convert molybdenum into soluble ammonium molybdate. The ammonium molybdate solution is then purified and neutralized with acid to prepare ammonium tetramolybdate. After ammonia dissolution, ammonium tetramolybdate is evaporated and crystallized to produce ammonium dimolybdate. This process inevitably introduces ammonia nitrogen reagents, thus unavoidably generating ammonia nitrogen waste pollutants.

[0003] To meet ammonia nitrogen emission standards, companies are forced to invest heavily in the construction and operation of ammonia nitrogen wastewater treatment facilities (such as stripping towers and biochemical treatment systems) and waste gas absorption towers, directly increasing smelting costs. On the other hand, the volatilization loss of ammonia also represents a waste of resources. Therefore, this problem urgently needs to be addressed in molybdenum smelting. The best approach is to avoid introducing ammonia nitrogen reagents altogether. Furthermore, ammonium dimolybdate, as an intermediate product, is calcined to produce molybdenum trioxide, decomposing to generate gas containing ammonia (NH3) and nitrogen oxides (NOx). χ The waste gas from the process causes secondary environmental pollution. Molybdenum trioxide is reduced to molybdenum dioxide via hydrogen reduction, and then further reduced to molybdenum powder, which is then used to make various molybdenum products. This multi-stage thermal conversion process is not only lengthy and requires significant equipment investment, but also demands precise control of parameters such as temperature, atmosphere, and material residence time at each stage. Fluctuations in any stage directly affect the particle size, morphology, and purity of the final molybdenum powder, increasing the difficulty of production control and the uncertainty of product quality.

[0004] Therefore, there is currently no technology in the molybdenum smelting process that can effectively extract molybdenum from molybdenite or molybdenum-containing raw materials without using ammonia nitrogen pollution. Summary of the Invention

[0005] In view of the above shortcomings, the present invention adopts the following technical means:

[0006] This invention first discloses a method for extracting molybdenum from molybdenum oxide raw materials, comprising:

[0007] (1) Molybdenum oxide raw material is mixed with a certain proportion of leaching agent and leached to obtain the first leachate for later use;

[0008] (2) The first leachate is purified by passing it through a resin (cationic resin or chelating resin) or an extractant (cationic extractant or chelating extractant) to obtain a molybdenum-containing purified solution;

[0009] (3) Add a control agent to the molybdenum-containing purification solution to obtain a precursor solution. Place the precursor solution in an autoclave for heating and decomposition to obtain the product.

[0010] Further, the molybdenum oxide raw materials in step (1) include: molybdenum roasted sand mainly composed of molybdenum oxide obtained by oxidative roasting of molybdenite; crude molybdenum oxide raw materials obtained from waste catalysts (molybdenum-nickel catalysts, molybdenum-cobalt catalysts, etc.); and crude molybdenum oxide raw materials obtained from waste molybdenum products (waste molybdenum wires, waste molybdenum electrodes, superalloy waste, etc.).

[0011] Further, the leaching agent in step (1) comprises a mixture of acid solution A and acid solution B.

[0012] Furthermore, the amount of acid solution A added is 0~5 mol / L, and acid solution A is selected from one or more of sulfuric acid, hydrochloric acid, nitric acid, and hydrogen peroxide.

[0013] Furthermore, the amount of acid solution B added is 0~5 mol / L, and acid solution B is selected from one or more of formic acid, acetic acid, citric acid, malic acid, oxalic acid, and tartaric acid.

[0014] Further, the liquid-to-solid ratio of the leaching agent to the molybdenum oxide raw material in step (1) is 2-1 to 8-1.

[0015] Furthermore, the leaching temperature in step (1) is controlled at 40~90℃, and the leaching time is 30min~8h.

[0016] Further, the resin in step (2) is a cationic resin or a chelating resin;

[0017] The extractant is selected from: cationic extractants or chelating extractants.

[0018] Further, the control agent in step (3) includes, but is not limited to, any one or more of the following: ethanol, acetone, glucose, sucrose, soluble starch, ethylene glycol, EDTA, diethylene glycol, and polyethylene glycol, and the amount added is 1% to 200% of the molar amount of molybdenum.

[0019] Furthermore, the heating decomposition temperature in step (3) is 100~300℃, and the heating decomposition time is 20min~30h.

[0020] The beneficial effects of this invention are as follows:

[0021] (1) Molybdenum dioxide products can be prepared in a short time, with simple steps and low economic cost.

[0022] (2) No ammonia nitrogen reagent is introduced throughout the process of this invention, thus avoiding the generation of ammonia nitrogen waste pollutants.

[0023] (3) The molybdenum leaching rate in the leaching process and the molybdenum precipitation rate in the product preparation process of the present invention exceed 99.5%. Attached Figure Description

[0024] Figure 1 XRD patterns of the examples and comparative samples;

[0025] Figure 2 Here is a scanning electron microscope image of the sample from Example 1;

[0026] Figure 3 Here is a scanning electron microscope image of the sample from Example 2;

[0027] Figure 4 Here is a scanning electron microscope image of the sample from Example 3;

[0028] Figure 5 Here is a scanning electron microscope image of the sample from Example 4;

[0029] Figure 6 Here is a scanning electron microscope image of the sample from Example 5;

[0030] Figure 7 This is a scanning electron microscope image of Comparative Example 1;

[0031] Figure 8 This is a scanning electron microscope image of Comparative Example 2. Detailed Implementation

[0032] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0033] Example 1

[0034] (1) The molybdenum roasted sand obtained by oxidative roasting of molybdenite was mixed with sulfuric acid (2 mol / L) and oxalic acid (1 mol / L) solution for leaching. The liquid-solid ratio was 3-1, the leaching temperature was controlled at 60℃, and the leaching time was 30 min. The molybdenum leaching rate reached 99.6%. The first leaching solution was obtained for later use.

[0035] (2) The first leachate is purified by passing it through D418 chelating resin to obtain a molybdenum-containing purified solution;

[0036] (3) Add ethanol (80% of the molar amount of molybdenum) to the molybdenum-containing purification solution to obtain a precursor solution. Place the precursor solution in an autoclave for heating and decomposition. The thermal decomposition temperature is 160℃ and the heating and decomposition time is 1h to obtain the sample. The molybdenum precipitation rate is 99.8%.

[0037] Example 2

[0038] (1) The crude molybdenum oxide raw material obtained from the waste catalyst (molybdenum-nickel catalyst, molybdenum-cobalt catalyst, etc.) was mixed with 2 mol / L oxalic acid solution for leaching. The liquid-solid ratio was 5-1, the leaching temperature was controlled at 70℃, and the leaching time was 30 min. The molybdenum leaching rate reached 99.7%. The first leachate was obtained for later use.

[0039] (2) The first leachate is purified by passing it through 732 cation exchange resin to obtain a molybdenum-containing purified solution;

[0040] (3) Add glucose (50% of the molar amount of molybdenum) to the molybdenum-containing purification solution to obtain a precursor solution. Place the precursor solution in an autoclave for heating and decomposition. The thermal decomposition temperature is 180℃ and the heating and decomposition time is 5h to obtain the sample. The molybdenum precipitation rate is 99.8%.

[0041] Example 3

[0042] (1) The crude molybdenum oxide raw material obtained from waste molybdenum products (waste molybdenum wire, waste molybdenum electrode, super alloy waste, etc.) is mixed with acetic acid (1 mol / L) and hydrochloric acid (2 mol / L) for leaching. The liquid-solid ratio is 7-1, the leaching temperature is controlled at 70℃, the leaching time is 30 min, and the molybdenum leaching rate reaches 99.7%. The first leaching solution is obtained for later use.

[0043] (2) The first leachate was purified by P204 cationic extractant to obtain a molybdenum-containing purified solution;

[0044] (3) Add ethylene glycol (40% of the molar amount of molybdenum) to the molybdenum-containing purification solution to obtain a precursor solution. Place the precursor solution in an autoclave for heating and decomposition. The thermal decomposition temperature is 200℃ and the heating and decomposition time is 10h to obtain the sample. The molybdenum precipitation rate is 99.5%.

[0045] Example 4

[0046] (1) The molybdenum roasted sand obtained by oxidative roasting of molybdenite was mixed with hydrochloric acid (2 mol / L) and hydrogen peroxide (1 mol / L) solution for leaching. The liquid-solid ratio was 6-1, the leaching temperature was controlled at 90℃, and the leaching time was 4h. The molybdenum leaching rate reached 99.6%. The first leaching solution was obtained for later use.

[0047] (2) The first leachate is purified by passing it through D851 chelating resin to obtain a molybdenum-containing purified solution;

[0048] (3) Add polyethylene glycol (10% of the molar amount of molybdenum) as a control agent to the molybdenum-containing purification solution to obtain a precursor solution. Place the precursor solution in an autoclave for heating and decomposition. The thermal decomposition temperature is 250℃ and the heating and decomposition time is 1h to obtain the sample. The molybdenum precipitation rate is 99.9%.

[0049] Example 5

[0050] (1) The crude molybdenum oxide raw material obtained from waste molybdenum products (waste molybdenum wire, waste molybdenum electrode, super alloy waste, etc.) is mixed with hydrogen peroxide solution (1 mol / L) for leaching. The liquid-solid ratio is 4-1, the leaching temperature is controlled at 40℃, the leaching time is 1 h, and the molybdenum leaching rate reaches 99.9%. The first leaching solution is obtained for later use.

[0051] (2) The first leachate was purified by P507 cationic extractant to obtain a molybdenum-containing purified solution;

[0052] (3) Add acetone (20% of the molar amount of molybdenum) to the molybdenum-containing purification solution to obtain a precursor solution. Place the precursor solution in an autoclave for heating and decomposition. The thermal decomposition temperature is 160℃ and the heating and decomposition time is 1h to obtain the sample. The molybdenum precipitation rate is 99.8%.

[0053] Comparative Example 1

[0054] It is basically the same as Example 1, except that it does not go through step (2) to remove impurities, which is used to verify the effect of step (2) on product impurities.

[0055] Comparative Example 2

[0056] It is basically the same as Example 1, except that the control agent in step (3) is not added to verify the control effect of the control agent on the phase and morphology.

[0057] Experimental Example 1

[0058] The samples from the above embodiments and comparative examples were subjected to partial impurity testing. The method was as follows: a certain mass of sample was treated with alkali dissolution mineral method, and the concentration of some impurities (Al, Fe, Cu, Ni, Co) was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The impurity content in the sample was calculated.

[0059] The test results are shown in Table 1.

[0060] Table 1. Content of some impurities in samples obtained from the examples and comparative examples.

[0061]

[0062] Conclusion: Step (2) can effectively remove cationic impurities from the sample.

[0063] Experimental Example 2

[0064] The samples of the above embodiments and comparative examples were subjected to phase and crystal structure analysis (XRD) using an X-ray diffractometer with Cu Kα rays and a scanning range of 10-80°.

[0065] Results: Test results are as shown in the attached instruction manual. Figure 1 The main diffraction peaks of the samples in Examples 1-5 and Comparative Example 1 all match the MoO2 standard card (PDF No. 32-0671); the main diffraction peak of the sample in Comparative Example 2 is MoO3 (PDF No. 05-0508).

[0066] Conclusion: The addition of a control agent affects the phase composition of the final product.

[0067] Experimental Example 3

[0068] The morphology of the samples from the above embodiments and comparative examples was observed using a scanning electron microscope.

[0069] Results: Scanning electron microscope results are as per the instruction manual. Figures 2-8 The MoO2 powders from Examples 1-5 and Comparative Example 1 are nearly spherical with a uniform particle size distribution within 50-70 nm, exhibiting good dispersibility. The MoO3 sample from Comparative Example 2 has an irregular blocky morphology with a particle size of 0.1-5 μm and poor uniformity.

[0070] Conclusion: The control agent can effectively control the particle size, morphology and dispersibility of the sample.

[0071] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; however, any combination of these technical features that does not contradict each other should be considered within the scope of this specification.

Claims

1. A method for extracting molybdenum from molybdenum oxide raw material, comprising: (1) mixing the molybdenum oxide raw material with a certain proportion of leaching agent for leaching to obtain a first leaching solution for standby; (2) removing impurities from the first leaching solution by resin or extractant to obtain a molybdenum-containing purified solution; (3) adding a control agent to the molybdenum-containing purified solution to obtain a precursor solution, and placing the precursor solution in an autoclave for heating decomposition.

2. The method of claim 1, wherein: the molybdenum oxide raw material of step (1) includes: products obtained by oxidizing and roasting molybdenite; crude molybdenum oxide raw material obtained from molybdenum-nickel catalyst, molybdenum-cobalt catalyst; and crude molybdenum oxide raw material obtained from waste molybdenum products.

3. The method of claim 1, wherein: the leaching agent of step (1) includes a mixture of acid solution A and acid solution B.

4. The method of claim 3, wherein: the amount of acid solution A added is 0-5 mol / L, and the acid solution A is selected from one or more of sulfuric acid, hydrochloric acid, nitric acid, and hydrogen peroxide.

5. The method of claim 3, wherein: the amount of acid solution B added is 0-5 mol / L, and the acid solution B is selected from one or more of formic acid, acetic acid, citric acid, malic acid, oxalic acid, and tartaric acid.

6. The method of claim 1, wherein: the liquid-solid ratio of the molybdenum oxide raw material to the leaching agent in step (1) is controlled at 2-1 to 8-1.

7. The method of claim 1, wherein: the leaching temperature in step (1) is controlled at 40-90℃, and the leaching time is 30min-8h.

8. The method of claim 1, wherein: the control agent in step (3) includes but is not limited to any one or more of ethanol, acetone, glucose, sucrose, soluble starch, ethylene glycol, EDTA, diethylene glycol, and polyethylene glycol, and the amount added is 1%-200% of the molar amount of molybdenum.

9. The method of claim 1, wherein: the heating decomposition temperature in step (3) is 100-300℃, and the heating decomposition time is 20min-30h.

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