Method for recovering ferro-molybdenum alloy through co-smelting of waste silicon-molybdenum rods and copper slag

Abstract

The embodiment of the invention relates to a method for recovering ferro-molybdenum through co-smelting of waste silicon-molybdenum rods and copper slag, and the method comprises the following steps: mixing the copper slag, the silicon-molybdenum rods, coke and calcium oxide to obtain a mixture; the mixture is heated, so that the copper slag and the coke are subjected to a smelting reduction reaction to obtain metal iron, molybdenum disilicide in the silicon molybdenum rod is subjected to a pyrolytic reaction under the action of the metal iron and calcium oxide, molten metal and molten slag are obtained, and the molten metal contains ferromolybdenum alloy components; according to the method, the molybdenum element in the waste silicon molybdenum rod can be fully enriched into iron, the recovery rate is high, the process is efficient and environmentally friendly, and waste liquid is not generated.

Description

Technical Field

[0001] The present application relates to the technical field of copper slag recovery and reuse and waste silicon-molybdenum rod recovery and reuse, and more specifically, to a method for recovering molybdenum-iron alloy by smelting waste silicon-molybdenum rods and copper slag together. Background Art

[0002] Copper is an indispensable basic material for modern industry. In 2023, refined copper was 12.99 million tons, a year-on-year increase of 13.5%. Copper slag is an important by-product of copper smelting. Generally, 2.2-3.0 tons of slag will be produced for every ton of refined copper produced. A large part of the copper slag is thrown into the processing pit. This not only causes waste of mineral resources and land occupation, but also causes serious environmental pollution. Copper slag pollution is particularly serious for land and groundwater systems in particular. China is the country with the richest molybdenum ore reserves in the world. At present, my country's molybdenum resource reserves are about 4.3 million tons, which plays an extremely important role in the development of industrialization. Molybdenum, as a strategic refractory metal, has a wide range of applications.

[0003] Copper slag is a system mainly based on iron alum, which is rich in precious resources such as iron and copper. The total iron weight is 40%, and the total copper weight is 0.5-3.0%. The iron grade in copper slag is even higher than that of some natural ores. In addition, if secondary resources are used to produce steel, the mining process of original iron ore can be saved, which has advantages in cost and environmental protection. Many technologies have been applied to the iron recovery process, mainly physical methods, hydrometallurgy, pyrometallurgy, etc. Methods for recovering iron from copper slag include direct ore dressing, oxidation modification, molten reduction, and direct reduction, but they generally have the problem of high cost and difficulty in large-scale industrialization.

[0004] Molybdenum disilicide was discovered in 1906 and began to be studied and used as a heating element in 1947. Silicon molybdenum rods are commonly used molybdenum disilicide heating elements. With the development of modern industry, silicon molybdenum rods are widely used in building materials industry, chemical industry, laboratories and other scenarios. Silicon molybdenum rods are often used in furnace heating elements for producing glassware, roller kiln heating elements for sintering colored glaze bricks, and electric furnace heating elements. Molybdenum is a rare metal. Molybdenum and its alloys and compounds have important applications in modern industry. With the large-scale application of silicon molybdenum rods, a large number of waste silicon molybdenum rods are generated. If they cannot be recycled, it will be a great waste of molybdenum resources. Waste silicon molybdenum rods are a kind of molybdenum-containing secondary resource with great application potential. Although the waste silicon molybdenum rods fail after a long period of use, their main components are still MoSi2 and a small amount of bentonite and silicon dioxide. They contain rich molybdenum resources, and the grade of molybdenum can reach 60%. However, due to the good acid and alkali resistance and high temperature resistance of molybdenum disilicide, it is difficult to efficiently recycle waste silicon-molybdenum rods. Currently, the roasting oxidation method and the nitric acid immersion method are commonly used. The roasting is time-consuming, energy-intensive, and requires relatively precise control of the roasting temperature. The nitric acid immersion method has a complicated acid leaching process, a relatively violent reaction, a high degree of danger, high requirements for equipment, and will produce more waste liquid. Due to the limitations of the process itself, it is difficult to improve the recovery efficiency. Summary of the invention

[0005] The present application is provided to solve the above-mentioned defects existing in the prior art. A method for recovering molybdenum-iron alloy by smelting waste silicon-molybdenum rods and copper slag together is needed, which can solve the high recovery cost of copper slag and waste silicon-molybdenum rods, and can also solve the problems of high energy consumption, difficulty in control and generation of waste liquid in the recovery method, and improve the recovery effect of waste silicon-molybdenum rods and copper slag.

[0006] In a first aspect of the present application, there is provided a method for recovering ferro-molybdenum alloy by smelting discarded silicon-molybdenum rods and copper slag together, the method comprising: mixing copper slag, silicon-molybdenum rods, coke and calcium oxide to obtain a mixture; heating the mixture so that the copper slag and the coke undergo a molten reduction reaction to obtain metallic iron, and the molybdenum disilicide in the silicon-molybdenum rods undergoes a pyrolysis reaction under the action of metallic iron and calcium oxide to obtain molten metal and slag, wherein the molten metal contains ferro-molybdenum alloy components; and separating the molten metal and the slag to obtain the ferro-molybdenum alloy.

[0007] The methods provided in the embodiments of the present application for smelting waste silicon-molybdenum rods and copper slag together to recover molybdenum-iron alloy, the copper slag and silicon-molybdenum rods are fully combined, the copper slag, silicon-molybdenum rods, coke and calcium oxide are mixed for melting reaction, not only can the iron in the copper slag be fully extracted at a relatively low cost, but also the material obtained by the copper slag reaction can promote the pyrolysis reaction of the silicon-molybdenum rods to fully recover the molybdenum element, the method of the present application does not require harsh conditions, is relatively easy to control, and does not produce waste liquid, the obtained slag can also be used to produce microcrystalline glass, realize the integration and recovery of valuable metals in two secondary resources, can fully enrich the molybdenum element in the waste silicon-molybdenum rods into iron, the recovery rate is high, the process is efficient and environmentally friendly, no waste liquid is produced, etc., and the utilization rate of resources such as copper slag and waste silicon-molybdenum rods is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In the drawings, which are not necessarily drawn to scale, the same reference numerals may describe similar parts in different views. The same reference numerals with letter suffixes or different letter suffixes may represent different instances of similar parts. The accompanying drawings generally illustrate various embodiments by way of example and not limitation, and together with the specification and claims, are used to illustrate the embodiments applied for. When appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the present apparatus or method.

[0009] Figure 1 The SEM-EDS image of the crude molybdenum-iron alloy according to Example 1 of the present application is shown. DETAILED DESCRIPTION

[0010] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is described in detail below in conjunction with the accompanying drawings and specific implementation examples. The embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and specific implementation examples, but are not intended to limit the present application.

[0011] The words "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements.

[0012] According to an embodiment of the present application, a method for recovering ferro-molybdenum alloy by smelting discarded silicon-molybdenum rods and copper slag together is provided, the method comprising: mixing copper slag, silicon-molybdenum rods, coke and calcium oxide to obtain a mixture; heating the mixture so that the copper slag and the coke undergo a molten reduction reaction to obtain metallic iron, and the molybdenum disilicide in the silicon-molybdenum rods undergoes a pyrolysis reaction under the action of metallic iron and calcium oxide to obtain molten metal and slag, wherein the molten metal contains ferro-molybdenum alloy components; separating the molten metal and the slag to obtain ferro-molybdenum alloy.

[0013] Coke is used as a reducing agent, and coke and copper slag undergo a molten reduction reaction to obtain metallic iron. The obtained metallic iron can be used as a metal capture agent to promote the pyrolysis of molybdenum disilicide. Calcium oxide is used to adjust the alkalinity in the reaction system to 0.7-1.3. Calcium oxide can reduce the viscosity of the slag system as a slag-making agent. As a desiliconizing agent and catalyst, it can promote the pyrolysis of molybdenum disilicide, facilitate the molten reduction reaction and metal capture and sedimentation, and facilitate the separation of metal and slag. Silicon molybdenum rods undergo pyrolysis reaction under the action of metallic iron and calcium oxide. During the pyrolysis reaction, molybdenum disilicide reacts with iron to obtain molybdenum-iron alloy components. The low-valent silicon in molybdenum disilicide acts as a reducing agent during the pyrolysis reaction, and the reaction is exothermic. The heat released is used for the pyrolysis reaction to maintain the temperature of the reaction, which is conducive to the recovery of heat energy, which can improve resource utilization and has good environmental friendliness. Silicon dioxide in copper slag can also be used as a slag-making agent, which is conducive to the separation of molybdenum-iron alloy and slag, and is conducive to the recovery and utilization of molybdenum resources.

[0014] The obtained slag contains a large amount of silicon and can be used to prepare microcrystalline glass after secondary treatment, thereby improving the utilization rate of resources.

[0015] Therefore, the mixed smelting of copper slag and silicon-molybdenum rods can not only fully recover the iron in the copper slag at a lower cost, but also make full use of metallic iron and silicon dioxide to recover the metallic molybdenum in the silicon-molybdenum rods, which is beneficial to reducing costs and obtaining molybdenum-iron alloy.

[0016] Ferromolybdenum is one of the molybdenum furnace materials with the largest output. In the steel industry, ferromolybdenum is the most commonly used additive for molybdenum alloy steel to improve the heat resistance, strength, corrosion resistance and other properties of alloy steel. The method of the present application can realize the utilization of valuable metal elements in copper slag and waste silicon-molybdenum rods.

[0017] The pyrometallurgical method of the present application can fully recover the molybdenum element in the silicon-molybdenum rod, the purity of the recovered ferro-molybdenum alloy is high, the content of the molybdenum element in the slag is almost 0, the molybdenum grade in the ferro-molybdenum alloy can be improved, and the recovery effect of the molybdenum element can be improved. In addition, the recovery method of the present application does not generate waste liquid, etc.

[0018] In some embodiments, the temperature of the heating treatment is 1400-1600° C. The silicon-molybdenum rod recovery method of the present application utilizes copper slag and silicon-molybdenum rods for mixed smelting, so that the silicon-molybdenum rods can undergo pyrolysis reaction at a temperature below 1600° C., thereby fully recovering the molybdenum element in the silicon-molybdenum rods.

[0019] In some embodiments, the heat treatment temperature is 1500-1550°C.

[0020] In some embodiments, the heating treatment time is 0.5-2 hours. Preferably, the heating treatment time is 1-1.5 hours.

[0021] In some embodiments, the mass ratio of copper slag to silicon-molybdenum rod is 3-5: 1. In this way, the molybdenum element in the silicon-molybdenum rod can be fully recovered.

[0022] In some embodiments, the amount of coke added is 1 / 22-1 / 18 of the mass of the copper slag. The coke fully acts as a reducing agent to fully recover the iron element in the copper slag and reduce the iron element in the slag. The mass content of iron element in the slag obtained in this application is less than 1%.

[0023] In some embodiments, the mass ratio of calcium oxide to copper slag is (0.5-1.2): 2. An appropriate amount of calcium oxide is added to adjust the basicity to 0.7-1.3.

[0024] In some embodiments, calcium fluoride is further added to the mixture and then subjected to a heating treatment. The addition of calcium fluoride can reduce the melting point of the slag system, thereby reducing energy consumption and reducing the viscosity of the slag system, which is beneficial to the separation of molten metal and slag and the recovery of ferromolybdenum alloy.

[0025] In some embodiments, the mass ratio of calcium fluoride to copper slag is 1-1.5:20. Adding an appropriate amount of calcium fluoride can help improve the recovery rate.

[0026] In some embodiments, the copper slag is firstly crushed and dried, and the silicon-molybdenum rod is crushed and then heated. The reaction effect between the silicon-molybdenum rod and the copper slag is better through sufficient crushing.

[0027] Example 1 The addition amount of each component is as follows: 10t of copper slag powder, the composition is shown in Table 1, 2.5t of waste silicon molybdenum rod powder is added, the composition is shown in Table 2, 500kg of coke is added, 5t of calcium oxide is added, and 500kg of calcium fluoride is added. After mixing the components, heat to 1500-1550℃ and keep warm for 1h. After the metal is separated from the slag, the Fe content in the slag is 0.83% and the Mo content in the slag is 0.0082%. The Mo content in the crude molybdenum-iron alloy is tested by ICP-MS, and the molybdenum grade in the crude molybdenum-iron alloy is 25.89%.

[0028] Table 1 Multi-element analysis results of copper slag (mass fraction %) Table 2 Element analysis results of waste silicon-molybdenum rods (mass fraction %) The crude molybdenum-iron alloy obtained in Example 1 was subjected to SEM (scanning electron microscope)-EDS (energy dispersive spectrometer) testing to obtain the following Figure 1 The results shown in the figure show that the mass fraction of molybdenum in the crude ferro-molybdenum alloy at point 1 is 32.4%, the mass fraction of iron is 64.5%, and the mass fraction of Zn is 3.1%. The mass fraction of molybdenum in the crude ferro-molybdenum alloy at point 2 is 2.26%, the mass fraction of iron is 96.84%, and the mass fraction of Zn is 0.9%.

[0029] Example 2 The amount of each component added is: 4t of copper slag powder, the composition is shown in Table 1, 1t of waste silicon molybdenum rod powder is added, the composition is shown in Table 2, the amount of coke added is 800kg, the amount of calcium oxide added is 2t, and the amount of calcium fluoride added is 300kg. After mixing the components, heat to 1500-1550℃ and keep warm for 1h. After the metal is separated from the slag, the Fe content in the slag is 0.43%, and the presence of molybdenum element is not detected in the slag. The Mo content in the crude molybdenum-iron alloy is tested by ICP-MS, and the molybdenum grade in the crude molybdenum-iron alloy is 32.47%.

[0030] Table 3 Element analysis results of waste silicon-molybdenum rods (mass fraction %) Example 3 The amount of each component added is: the amount of copper slag powder is 4t, the composition is shown in Table 1, 1t of waste silicon molybdenum rod powder is added, the composition is shown in Table 2, the amount of coke added is 800kg, the amount of calcium oxide added is 1.8t, and the amount of calcium fluoride added is 300kg. After mixing the components, heat to 1500-1550℃ and keep warm for 1h. After the metal is separated from the slag, the Fe content in the slag is 0.82%, and the presence of molybdenum element is not detected in the slag. The Mo content in the crude molybdenum-iron alloy was tested by ICP-MS, and the molybdenum grade in the crude molybdenum-iron alloy was 28.71%.

[0031] Example 4 The amount of each component added is: 4t of copper slag powder, the composition is shown in Table 1, 1t of waste silicon molybdenum rod powder is added, the composition is shown in Table 2, the amount of coke added is 800kg, the amount of calcium oxide added is 1.6t, and the amount of calcium fluoride added is 300kg. After mixing the components, heat to 1500-1550℃ and keep warm for 1h. After the metal is separated from the slag, the Fe content in the slag is 0.71%, and the presence of molybdenum element is not detected in the slag. The Mo content in the crude molybdenum-iron alloy is tested by ICP-MS, and the molybdenum grade in the crude molybdenum-iron alloy is 28.52%.

[0032] It can be seen from Examples 1 to 4 that the recovery method of the present application can fully recover the iron in the copper slag and the molybdenum in the silicon-molybdenum rods, and the obtained crude molybdenum-iron alloy contains a higher mass fraction of molybdenum and iron elements, while the content of other elements is relatively small.

[0033] In addition, although exemplary embodiments have been described herein, the scope includes any and all embodiments based on the present application with equivalent elements, modifications, omissions, combinations (e.g., various embodiments intersecting schemes), adaptations or changes. The elements in the claims are to be interpreted broadly based on the language adopted in the claims, and are not limited to the examples described in this specification or during the practice of this application, and the examples are to be interpreted as non-exclusive. Therefore, this specification and examples are intended to be considered as examples only, and the true scope and spirit are indicated by the following claims and the full scope of their equivalents.

[0034] The above description is intended to be illustrative rather than restrictive. For example, the above examples (or one or more schemes thereof) may be used in combination with each other. For example, a person of ordinary skill in the art may use other embodiments when reading the above description. In addition, in the above-mentioned specific embodiments, various features may be grouped together to simplify the present application. This should not be interpreted as an intention that a feature of an application that does not require protection is necessary for any claim. On the contrary, the subject matter of the present application may be less than all the features of an embodiment of a particular application. Thus, the following claims are incorporated herein in the specific embodiments as examples or embodiments, wherein each claim is independently a separate embodiment, and it is considered that these embodiments may be combined with each other in various combinations or arrangements. The scope of the present invention should be determined with reference to the appended claims and the full scope of equivalent forms granted by these claims.

[0035] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A method for recovering ferro-molybdenum alloy by smelting waste silicon-molybdenum rods and copper slag, characterized in that: The method comprises: mixing copper slag, silicon-molybdenum rods, coke and calcium oxide to obtain a mixture; heating the mixture so that the copper slag and the coke undergo a molten reduction reaction to obtain metallic iron, and the molybdenum disilicide in the silicon-molybdenum rods undergoes a pyrolysis reaction under the action of the metallic iron and calcium oxide to obtain molten metal and slag, wherein the molten metal contains a molybdenum-iron alloy component; and separating the molten metal and the slag to obtain a molybdenum-iron alloy.

2. The method according to claim 1, characterized in that The temperature of the heating treatment is 1400-1600°C.

3. The method according to claim 2, characterized in that The temperature of the heating treatment is 1500-1550°C.

4. The method according to claim 1, characterized in that The heating treatment time is 0.5-2h.

5. The method according to claim 1, characterized in that The mass ratio of copper slag to silicon-molybdenum rod is 3-5:

1.

6. The method according to claim 1, characterized in that The amount of coke added is 1 / 22-1 / 18 of the mass of the copper slag.

7. The method according to claim 1, characterized in that The mass ratio of calcium oxide to copper slag is (0.5-1.2):

2.

8. The method according to claim 1, characterized in that Calcium fluoride is also added to the mixture, which is then subjected to a heat treatment.

9. The method according to claim 8, characterized in that The mass ratio of calcium fluoride to copper slag is 1-1.5:

20.

10. The method according to claim 1, characterized in that Firstly, the copper slag is crushed and dried, and the silicon-molybdenum rod is crushed and then heated.

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