阅读说明：本技术 一种利用碳化铬制备金属铬的方法 (Method for preparing chromium metal by using chromium carbide ) 是由 付莹 孔祥清 付连生 于占东 张婷婷 牛秀梅 周渊明 张鹏 于 2020-04-30 设计创作，主要内容包括：本发明提出了一种利用碳化铬制备金属铬的方法,属于工业固体废弃物资源化利用领域和有色金属的处理技术领域,其特征是以铝铬渣生产铬刚玉过程中形成的碳化铬副产品作为原料,解决了固体废弃物的资源化利用问题,所生产的产品符合95金属铬要求,原材料价格低廉,生产成本低；工艺相对简单,生产效率高,对环境影响小；实现了铝铬渣及其副产品的资源化循环利用,节约资源,对环境友好,是金属铬的生产提供了一种较理想的方法。(The invention provides a method for preparing chromium metal by using chromium carbide, belonging to the field of resource utilization of industrial solid wastes and the technical field of treatment of nonferrous metals, which is characterized in that a chromium carbide byproduct formed in the process of producing chromium corundum by using aluminum chromium slag is used as a raw material, so that the resource utilization problem of the solid wastes is solved, the produced product meets the requirement of 95 chromium metal, the price of the raw material is low, and the production cost is low; the process is relatively simple, the production efficiency is high, and the influence on the environment is small; realizes the resource recycling of the aluminum chromium slag and the byproducts thereof, saves resources, is environment-friendly, and provides an ideal method for the production of metal chromium.)

1. A method for preparing metallic chromium by using chromium carbide is characterized by comprising the following steps:

a, preparing raw materials: crushing the aluminum chromium slag to obtain aluminum chromium slag particles; mixing the aluminum chromium slag particles and the petroleum coke particles and then adding the mixture into an electric arc furnace; after the arc furnace was started, the temperature in the vicinity of the graphite electrode rapidly increased, and when the temperature reached 2039K, Cr was present₇C₃Melting, aggregating and sinking to finally obtain Cr₇C₃Block, crushing, ball milling to obtain powder, selecting certain amount of Cr₂O₃And Cr₇C₃The powders are mixed uniformly.

B, feeding raw materials into a furnace: putting the mixture into a furnace chamber of a vacuum induction heating furnace, starting a vacuum system, starting the heating system when the vacuum degree reaches 10Pa, increasing the temperature at a rate of 50 ℃/min, keeping the temperature constant when the temperature reaches 1450 ℃, and keeping Cr constant₇C₃And Cr₂O₃Reacting at high temperature to generate chromium metal and carbon monoxide, continuously discharging the generated carbon monoxide under vacuum or negative pressure until the vacuum degree is maintained within the range of 1-20Pa, keeping constant temperature for 5 hours, ensuring full reaction, and closing a vacuum system.

2. The method for preparing metallic chromium by using chromium carbide as claimed in claim 1, wherein the Cr in the step A is₇C₃And Cr₂O₃The mass ratio of (A) to (B) is as follows: 1:1-3:1.

3. The method for preparing metallic chromium by using chromium carbide as claimed in claim 1, wherein the crushed aluminum chromium slag in the step A has a particle size of less than or equal to 10 mm.

4. The method for preparing metallic chromium from chromium carbide as claimed in any one of claims 1 to 6, wherein the Cr in step A is₇C₃The powder is 80-120 mesh.

Technical Field

The invention relates to the field of resource utilization of industrial solid wastes and the technical field of treatment of nonferrous metals, in particular to a method for preparing chromium metal by using chromium carbide.

Background

As an important strategic resource, chromium has the excellent characteristics of high hardness, good wear resistance, high temperature resistance, corrosion resistance and the like, and is widely applied to smelting high-temperature alloys, resistance alloys, precision alloys and other non-ferrous alloys.

At present, the industrial production process of metal chromium mainly adopts smelting technologies such as an electrolytic method, a metal chromium smelting furnace method and the like. In the process of producing the metal chromium by the metallothermic reduction method, the production cost of the metal chromium is high due to the high price of aluminum powder serving as a reducing agent, and the quality of the metal chromium produced by the metallothermic reduction method is inferior to that produced by an electrolytic method. In the production process of the electrolytic method, the existing production process is not only complex in process, but also high in energy consumption and cost. With the increasing importance of energy utilization, the development of energy-saving chromium metal production process is an irresistible trend.

The aluminum chromium slag is a byproduct derived from smelting metal chromium by aluminothermic reduction reaction. When smelting chromium metal, the reduction reaction of metallic aluminium and industrial chromium oxide is used to prepare chromium metal, and the metallic aluminium powder and Cr₂O₃In a molten state, a drastic chemical reaction occurs to produce Al₂O₃Quickly convert to corundum phase and simultaneously react with unreacted Cr₂O₃Solid solution is carried out to generate an aluminum chromium solid solution, namely aluminum chromium slag. Generally, every one ton of metal chromium produced discharges 15 tons of aluminum-chromium slag, and the main component of the aluminum-chromium slag is A1₂O₃And Cr₂O₃. The aluminum chromium slag has certain harmfulness to ecological environment and the like, but if the treatment is proper, the aluminum chromium slag is also an available resource.

Disclosure of Invention

The invention aims to provide a method for preparing metal chromium by using a chromium carbide byproduct formed in the process of producing chrome corundum by using industrial waste aluminum-chromium slag as a raw material, and simultaneously solves the problems of environmental pollution and resource recycling of solid waste aluminum-chromium slag.

In order to achieve the purpose, the invention provides the following technical scheme:

a method for preparing metallic chromium by using chromium carbide, comprising the following steps:

a, preparing raw materials: crushing the aluminum chromium slag to obtain aluminum chromium slag particles; mixing the aluminum chromium slag particles and the petroleum coke particles and then adding the mixture into an electric arc furnace; after the arc furnace was started, the temperature in the vicinity of the graphite electrode rapidly increased, and when the temperature reached 2039K, Cr was present₇C₃Melting, aggregating and sinking to finally obtain Cr₇C₃Block, crushing, ball milling to obtain powder, selecting certain amount of Cr₂O₃And Cr₇C₃The powders are mixed uniformly.

B, feeding raw materials into a furnace: putting the mixture into a furnace chamber of a vacuum induction heating furnace, starting a vacuum system, starting the heating system when the vacuum degree reaches 10Pa, increasing the temperature at a rate of 50 ℃/min, keeping the temperature constant when the temperature reaches 1450 ℃, and keeping Cr constant₇C₃And Cr₂O₃Reacting at high temperature to generate chromium metal and carbon monoxide, continuously discharging the generated carbon monoxide under vacuum or negative pressure until the vacuum degree is maintained within the range of 1-20Pa, keeping constant temperature for 5 hours, ensuring full reaction, and closing a vacuum system.

As a further technical scheme of the invention: cr in the step A₇C₃And Cr₂O₃The mass ratio of (A) to (B) is as follows: 1:1-3:1.

As a further technical scheme of the invention: and C, the granularity of the crushed aluminum chromium slag in the step A is less than or equal to 10 mm.

As a further technical scheme of the invention: cr in the step A₇C₃The powder is 80-120 mesh.

Compared with the prior art, the invention has the beneficial effects that: the method takes the chromium carbide byproduct formed in the process of producing the chrome corundum by using the industrial waste aluminum chromium slag as the raw material to prepare the metal chromium, solves the problem of discharging solid waste, consumes a large amount of the aluminum chromium slag and the chromium carbide byproduct thereof, relieves the harm of the aluminum chromium slag to the environment, realizes the resource recycling of the aluminum chromium slag, saves resources and is environment-friendly.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A method for preparing metal chromium by using chromium carbide, which simultaneously solves the problems of environmental pollution and resource recycling of solid waste aluminum-chromium slag.

The aluminum chromium slag particles are slag generated by smelting metal chromium, and the chemical components of the aluminum chromium slag particles are Al₂O₃75 to 85 wt% of Cr₂O₃8-15 wt%, CaO is less than or equal to 3 wt%, Fe₂O₃Less than or equal to 2 weight percent, and less than or equal to 2 weight percent of MgO; the grain size of the aluminum chromium slag is less than or equal to 10 mm. Al (Al)₂O₃Has a melting point of 2327K and a density of 3.9g/cm³，Cr₂O₃Has a melting point of 2539K and a density of 5.21g/cm³Melting point of C3823K and density of 2.26g/cm³，Cr₇C₃The melting point is 2039K, and the density is 6.89g/cm³. After the electric arc furnace is started, the temperature near the graphite electrode is rapidly increased, and according to the thermodynamic principle, when the temperature is 1400K, C and Cr₂O₃Reaction to produce Cr₇C₃The standard Gibbs free energy of (A) is less than zero, which shows that the carbon reduction reaction can automatically proceed, the reaction trend is stronger along with the increase of the temperature, and Cr is obtained when the temperature reaches 2039K₇C₃Starts to melt and aggregate, and sinks continuously due to the higher density of the alloy compared with other oxides to finally form Cr₇C₃And (3) a block body. Al when the temperature reaches 2327K₂O₃Melting begins, Al due to the greater density difference₂O₃And Cr₇C₃Layering is formed, and on one hand, Al with higher purity is obtained₂O₃The product, on the other hand, obtains cheap Cr₇C₃. Further, the metallic chromium with higher added value is prepared by a vacuum reduction method, so that the comprehensive utilization of solid waste resources is realized to the maximum extent. Produced Cr₇C₃The main components of the alloy are 84.52% of chromium, 8.65% of carbon and 1.66% of iron. Using Cr₇C₃The reaction principle for preparing the ferrochrome nitride is as follows:

Cr₇C₃+Cr₂O₃＝9Cr+3CO

Cr₇C₃and Cr₂O₃The reaction is carried out at high temperature to generate metal chromium and carbon monoxide, the generated carbon monoxide is continuously discharged under vacuum or negative pressure, whether carbon monoxide is discharged or not can be judged through the display value of a vacuum gauge, and the metal chromium is finally formed after the reaction is full.

A method for preparing metallic chromium by using chromium carbide, which comprises the following steps:

preparing raw materials: crushing the aluminum chromium slag until the granularity is less than or equal to 10mm to obtain aluminum chromium slag particles; mixing the aluminum chromium slag particles and the petroleum coke particles and then adding the mixture into an electric arc furnace; after the arc furnace was started, the temperature in the vicinity of the graphite electrode rapidly increased, and when the temperature reached 2039K, Cr was present₇C₃Melting, aggregating and sinking to finally obtain Cr₇C₃And (3) blocking, and crushing and ball-milling the block into powder of 80-120 meshes. Selecting a certain amount of Cr₂O₃And Cr₇C₃The powder is mixed evenly, the Cr is₇C₃And Cr₂O₃The mass ratio of (A) to (B) is as follows: 1:1-3:1. Feeding raw materials into a furnace: putting the mixture into a furnace chamber of a vacuum induction heating furnace, starting a vacuum system, starting the heating system when the vacuum degree reaches 10Pa, increasing the temperature at a rate of 50 ℃/min, keeping the temperature constant when the temperature reaches 1450 ℃, and keeping Cr constant₇C₃And Cr₂O₃Reacting at high temperature to generate chromium metal and carbon monoxide, continuously discharging the generated carbon monoxide under vacuum or negative pressure until the vacuum degree is maintained within the range of 1-20Pa, keeping constant temperature for 5 hours, ensuring full reaction, and closing a vacuum system.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following positive effects:

1. the method prepares the metal chromium by taking the chromium carbide byproduct formed in the process of producing the chrome corundum by using the industrial waste aluminum-chromium slag as the raw material, solves the problem of discharging solid waste, realizes the resource recycling of the aluminum-chromium slag, saves resources, is environment-friendly, and can save 5 ten thousand tons of bauxite ore and 1 ten thousand tons of chromium ore per year according to the calculation of the conversion amount of 3.4 ten thousand tons of aluminum-chromium slag per year. The produced product meets the requirement of 95 chromium metal materials, and can be used as an additive in the preparation process of steel and non-ferrous metal alloys.

2. The raw material price is low, the production cost is low, and is 20 to 30 percent lower than that of the conventional method.

3. The process is relatively simple, the production efficiency is high, and the influence on the environment is small.

Therefore, the method can effectively consume the chromium carbide, improve the additional value of the chromium carbide and is environment-friendly.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.