阅读说明：本技术 一种利用电弧炉冶炼生产碳化铬的方法 (Method for producing chromium carbide by smelting in electric arc furnace ) 是由 寇志远 寇志玲 张晓梅 于 2020-05-26 设计创作，主要内容包括：一种利用电弧炉冶炼生产碳化铬的方法,将氧化铬和碳粉按比例充分混合均匀,喷洒结合剂木质素,压柱烘干,装入电弧炉中,并加入熔剂二铝酸钙或铝酸钙,引弧冶炼,冶炼温度控制在1500℃～2000℃,冶炼时间控制在3h～12h,将冶炼完毕的液态混合熔体倾倒在容器中,将容器中的碳化铬与二铝酸钙/铝酸钙缓慢降温200℃以下,保证晶格生长时间控制在24h～96h；渣铁分离,破碎、精整,得到碳化铬。优点是：以氧化铬和碳粉为原料,采用电弧炉冶炼生产,获得的碳化铬为斜方晶系,密度为6.68g/cm<Sup>3</Sup>,且工艺简单,对原料要求不高,无游离碳生成,无需严格控制配碳量,且产品内的金属Al、Si和非金属杂质S、P含量较低。(A method for producing chromium carbide by smelting in an electric arc furnace comprises the steps of fully and uniformly mixing chromium oxide and carbon powder in proportion, spraying a binding agent lignin, pressing a column for drying, loading into the electric arc furnace, adding a flux calcium dialuminate or calcium aluminate, carrying out arc-striking smelting, controlling the smelting temperature to be 1500-2000 ℃, controlling the smelting time to be 3-12 h, pouring a liquid mixed melt after the smelting into a container, slowly cooling the chromium carbide and the calcium dialuminate/calcium aluminate in the container to be below 200 ℃, and ensuring that the crystal lattice growth time is controlled to be 24-96 h; separating slag iron, crushing and finishing to obtain chromium carbide. The advantages are that: chromium oxide and carbon powder are used as raw materials, the raw materials are smelted and produced by an electric arc furnace, the obtained chromium carbide is an orthorhombic system, and the density is 6.68g/cm 3 The method has the advantages of simple process, low requirements on raw materials, no free carbon generation, no need of strict control of carbon blending amount, and low contents of metal Al, Si and non-metal impurity S, P in the product.)

1. A method for producing chromium carbide by smelting in an electric arc furnace is characterized by comprising the following steps:

the method comprises the following specific steps:

(1) fully and uniformly mixing the chromium oxide and the carbon powder according to a proportion, spraying a binding agent lignin, and pressing and drying a column to obtain a chromium oxide-carbon powder column;

(2) putting the chromium oxide-carbon powder cylinder into an electric arc furnace, and adding a flux, wherein the flux is calcium dialuminate or calcium aluminate, and the mass ratio of the chromium oxide-carbon powder cylinder to the flux is 1: 1-1: 10; arc striking smelting, wherein the smelting temperature is controlled to be 1500-2000 ℃, the smelting time is controlled to be 3-12 h, the smelted mixed melt of liquid chromium carbide and calcium dialuminate/calcium aluminate is poured into a container, the temperature of the chromium carbide and the calcium dialuminate/calcium aluminate in the container is slowly reduced to be below 200 ℃, and the growth time of crystal lattices is controlled to be 24-96 h; and pouring the cooled chromium carbide and the calcium dialuminate/calcium aluminate out of the cooler, separating slag from iron, crushing and finishing to obtain the chromium carbide.

2. The method for producing chromium carbide by using the electric arc furnace smelting according to claim 1, which is characterized by comprising the following steps: the size of the silicon oxide-carbon powder cylinder isThe height is 20 mm-40 mm.

3. The method for producing chromium carbide by using the electric arc furnace smelting according to claim 1, which is characterized by comprising the following steps: the mass ratio of the chromium oxide to the carbon powder in the step (1) is 100: 20-100: 40.

4. The method for producing chromium carbide by using the electric arc furnace smelting according to claim 1, which is characterized by comprising the following steps: the mass ratio of the total mass of the chromium oxide and the carbon powder to the lignin is 100: 4-100: 10.

5. The method for producing chromium carbide by using the electric arc furnace smelting according to claim 1, which is characterized by comprising the following steps: the iron and silicon impurity elements in the calcium dialuminate or the calcium aluminate are controlled to be 0.05 to 0.1 percent by mass.

6. The method for producing chromium carbide by using the electric arc furnace smelting according to claim 1, which is characterized by comprising the following steps: the particle size of the calcium dialuminate or the calcium aluminate is less than or equal to 50 mm.

Technical Field

The invention relates to a method for producing chromium carbide by smelting in an electric arc furnace.

Background

Chromium carbide, orthorhombic system, carbon content 13.3%, crystal structure: 2.821, 5.52 for b, 11.46 for c, and 6.68g/cm for relative density³Melting point 1890 ℃, boiling point 3800 ℃ and thermal expansion coefficient 10.3 × 10^-6and/K. The orthorhombic chromium carbide has good wear-resistant, corrosion-resistant and oxidation-resistant high-melting-point material under the high-temperature environment of 1000-1100 ℃, and hard alloy particles prepared from the orthorhombic chromium carbide and nickel-chromium alloy can be used as a high-temperature-resistant, wear-resistant, oxidation-resistant and acid-resistant coating by adopting a plasma spraying method, and can be widely used for aircraft engineThe service life of the machine and the petrochemical engineering machinery can be greatly prolonged.

At present, a vacuum furnace is mainly used for producing chromium carbide, and the production process mainly comprises the following two steps: one method is to use chromium oxide as a raw material and mix a pressing column with carbon powder, put the pressing column into a vacuum furnace, control the temperature at 1100-1600 ℃, control the pressure at 10-60 Pa, and smelt for 8-60 h. Obtaining 12 to 13.2 percent of carbon, less than or equal to 0.3 percent of free carbon, 88 to 85.8 percent of chromium and 6.613g/cm of relative density³An orthorhombic system. The disadvantages are that: 1. because of the solid-state reaction under the vacuum condition, free carbon can not be removed, and the use effect is influenced; 2. because the generation of chromium carbide is in a cylindrical particle state, the particle size can only be controlled to be more than or equal to 200 meshes during grinding, the chromium carbide cannot be ground to be less than 200 meshes, and the application range is narrow; 3. non-metallic impurities are high, such as: s, P the content is high; 4. the density is less than 6.613g/cm³The high-quality chromium carbide is not up to 6.68g/cm³. The other method is to use powdery metal chromium as a raw material and mix the powdery metal chromium with carbon powder to form a compression column, and the compression column is put into a vacuum furnace, the temperature is controlled to be 1400-1600 ℃, the pressure is 10-60 Pa, and the time is 8-48 h. 9 to 18 percent of carbon, less than or equal to 0.3 percent of free carbon, 91 to 82 percent of chromium and 6.68/cm of relative density are obtained³And (3) crystallizing: the lattice is positive and negative. The disadvantages are that: 1. free carbon can not be removed, so that the use effect is influenced; 2. because the used raw material powdery metal chromium contains high Al, Fe and Si, can not be discharged and is directly brought into a chromium carbide product, the application range is narrow; 3. non-metallic impurities are high, such as: s, P the content is high; 4. the crystal lattice is a two-dimensional positive and negative crystal form, and an orthorhombic crystal form a is 2.821, b is 5.52 and c is 11.46 is not generated.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a method for producing chromium carbide by smelting in an electric arc furnace, wherein chromium oxide and carbon powder are used as raw materials, the electric arc furnace is adopted for smelting production, the obtained chromium carbide is an orthorhombic system, and the density is 6.68g/cm³The method has the advantages of simple process, low requirements on raw materials, no free carbon generation, no need of strict control of carbon blending amount, and low contents of metal Al, Si and non-metal impurity S, P in the product.

The technical scheme of the invention is as follows:

a method for producing chromium carbide by smelting in an electric arc furnace comprises the following specific steps:

(1) fully and uniformly mixing the chromium oxide and the carbon powder according to a proportion, spraying a binding agent lignin, and pressing and drying a column to obtain a chromium oxide-carbon powder column;

(2) putting the chromium oxide-carbon powder cylinder into an electric arc furnace, and adding a flux, wherein the flux is calcium dialuminate or calcium aluminate, and the mass ratio of the chromium oxide-carbon powder cylinder to the flux is 1: 1-1: 10; arc striking smelting, wherein the smelting temperature is controlled to be 1500-2000 ℃, the smelting time is controlled to be 3-12 h, the smelted liquid chromium carbide and calcium dialuminate/calcium aluminate mixed melt is poured into a container, the chromium carbide and the calcium dialuminate/calcium aluminate deposited in the container can be layered due to the fact that the density of the chromium carbide is far greater than that of the calcium dialuminate/calcium aluminate, separation treatment is facilitated, the temperature of the chromium carbide and the calcium dialuminate/calcium aluminate in the container is slowly reduced to be below 200 ℃, the crystal lattice growth time is controlled to be 24-96 h, and the crystal lattice growth time is generated as follows: 2.821, 5.52 and 11.46 orthorhombic chromium carbide; pouring the cooled chromium carbide and calcium dialuminate/calcium aluminate out of the cooler, and separating slag from iron; and (3) obtaining solid chromium carbide, crushing and finishing, wherein the granularity can provide products with different granularity levels of 40-600 meshes according to the requirements of users.

Further, the size of the silicon oxide-carbon powder cylinder isThe height is 20 mm-40 mm.

Further, the mass ratio of the chromium oxide to the carbon powder in the step (1) is 100: 20-100: 40.

Further, the mass ratio of the total mass of the chromium oxide and the carbon powder to the lignin is 100: 4-100: 10.

Furthermore, the iron and silicon impurity elements in the calcium dialuminate or the calcium aluminate are controlled to be 0.05 to 0.1 percent by mass.

The particle size of the calcium dialuminate or the calcium aluminate is less than or equal to 50 mm.

The chemical reaction formula for producing the chromium carbide is as follows:

2/3Cr₂O₃+26/9C＝4/9Cr₃C₂+2CO↑；

△G^{powder medicine}＝506900-366.05T_{1 on}，T_{1 on}1385k, the ratio of C is 13.3%.

2/3Cr₂O₃+18/7C＝4/21Cr₇C₃+2CO↑；

△G^{Powder medicine}＝521920-359.11T_2-opening，T_2-opening1453k, C ratio is 9%.

The invention relates to a method for producing chromium carbide by smelting in an electric arc furnace, which has the advantages that:

(1) chromium carbide is produced by reducing chromium oxide with carbon powder, the crystal production of the chromium carbide can be controlled to be an orthorhombic system, the crystal form a is 2.821, the crystal form b is 5.52, and the crystal form c is 11.46; smelting in an electric arc furnace, reacting a part of chromium carbide and carbon powder in a solid-solid state, changing the part of chromium carbide and carbon powder into a molten state along with the increase of the temperature of the electric arc furnace, continuously reacting in a liquid-liquid state, floating the carbon powder which does not react with chromium oxide in the molten state to a slag surface due to light density, reacting with oxygen in the air to generate CO, generating no free carbon in the final chromium carbide product, and enabling the relative density of the chromium carbide to accord with a standard value of 6.68g/cm³Left and right;

(2) calcium dialuminate or calcium aluminate is used as a fusing agent, a composite compound of the calcium dialuminate or the calcium aluminate has a heat conduction effect, so that chromium oxide and carbon which participate in the reaction are carried out at the same temperature as far as possible, and the melting point of the fusing agent is lower than that of liquid chromium carbide, so that the fluidity of furnace burden is improved, the viscosity of liquid materials is reduced, the recovery rate of chromium carbide is improved, sticky liquid chromium carbide is prevented from being attached to a furnace wall and a furnace bottom, and the liquid chromium carbide can be quickly gathered together;

(3) the calcium dialuminate or calcium aluminate can play the role of desulfurizing, dephosphorizing and other impurities, and can reduce the contents of sulfur and phosphorus in chromium carbide, its proportioning ratio for removing sulfur and phosphorus is ①, and the distribution ratio of sulfur is that when the sulfur is greater than 1200 deg.C, about 5% of sulfur is fed into alloy, about 30% of sulfur is fed into slag and about 65% of sulfur is discharged into air, and the distribution ratio of ② phosphorus is that when the temperature is controlled above 1200 deg.C, phosphorus and calcium oxide can form calcium phosphate, and the dephosphorizing rate can be up to above 70%, and the content of metal impurity can be controlled, and the SiO in raw material can be used for making alloy with₂Removing impuritiesMore than 60 percent of calcium silicate is removed, the generated calcium silicate enters a slag phase, and the product quality is excellent.

Detailed Description