阅读说明：本技术 一种以铝铬渣为主料在真空烧结炉中真空脱碳生产金属铬的工艺 (Process for producing metallic chromium by taking aluminum-chromium slag as main material and performing vacuum decarburization in vacuum sintering furnace ) 是由 高红军 赵鹏达 冯继刚 陈位移 曹杨 田刚 于 2020-05-11 设计创作，主要内容包括：一种以铝铬渣为主料在真空烧结炉中真空脱碳生产金属铬的工艺,将铝铬渣和碳质原料混合,置于三相电弧炉熔炼后,自然冷却,分离出下层碳化铬；将碳化铬研磨后,再与氧化铬、防爆纤维、碳质原料、甲基纤维素、水混合均匀,压制成圆柱状混合料棒,置于真空烧结炉中,在25℃～70℃保温2～3小时并使真空度降至10<Sup>-1</Sup>Pa以下,继续升温至1300℃～1500℃,真空烧结10小时～30小时,随炉冷却,得到金属铬。优点是：原料成本低廉,无需特殊的生产设备及处理手段,节省劳动力资源,工艺流程简单,产品提取率高。(A process for producing metallic chromium by using aluminum chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace comprises the steps of mixing the aluminum chromium slag with a carbonaceous raw material, putting the mixture into a three-phase arc furnace for smelting, naturally cooling, and separating out lower-layer chromium carbide; grinding chromium carbide, uniformly mixing with chromium oxide, explosion-proof fiber, carbonaceous raw material, methyl cellulose and water, pressing into a cylindrical mixed material rod, placing the cylindrical mixed material rod into a vacuum sintering furnace, preserving heat for 2-3 hours at 25-70 ℃, and reducing the vacuum degree to 10 ‑1 And (4) continuously heating to 1300-1500 ℃ below Pa, carrying out vacuum sintering for 10-30 hours, and cooling along with the furnace to obtain the metal chromium. The advantages are that: low raw material cost, no need of special production equipment and treatmentMeans, labor resource saving, simple process flow and high product extraction rate.)

1. A process for producing metallic chromium by using aluminum chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace is characterized by comprising the following steps of:

(1) mixing the aluminum chromium slag and the carbonaceous raw material, putting the mixture into a three-phase electric arc furnace for smelting, naturally cooling, and separating out lower-layer chromium carbide;

(2) grinding the chromium carbide obtained in the step (1) into particles with the particle size of 80-150 meshes, and uniformly mixing the chromium carbide, chromium oxide, explosion-proof fiber, a carbonaceous raw material, methyl cellulose and water according to a mass ratio of 70: (20-40), 70: (0-2) and 70: (0-4) and 70: (0-2) and 70: (0-2), pressing into a cylindrical mixed material rod, placing the cylindrical mixed material rod in a vacuum sintering furnace, preserving the heat for 2-3 hours at the temperature of 25-70 ℃, and reducing the vacuum degree to 10^-1And (4) continuously heating to 1300-1500 ℃ below Pa, carrying out vacuum sintering for 10-30 hours, and cooling along with the furnace to obtain the metal chromium.

2. The process for producing metallic chromium by using aluminum-chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace according to claim 1, which is characterized by comprising the following steps: the mass ratio of the chromium carbide to the chromium oxide to the explosion-proof fiber to the carbonaceous raw material to the methyl cellulose to the water is 70: (35-40), 70: (1.5-2) and 70: (3-4) and 70: (1.5-2) and 70: (1.5-2).

3. The process for producing metallic chromium by using aluminum-chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace according to claim 1, which is characterized by comprising the following steps: the aluminum chromium slag particles are slag generated by smelting ferrochrome, and the main phases are corundum phase and aluminum chromium solid solution phase; the main chemical components of the aluminum chromium slag particles are as follows: al (Al)₂O₃75 to 85 weight percent of Cr₂O₃10 to 15 weight percent of CaO, less than or equal to 3 weight percent of CaO, Fe₂O₃Less than or equal to 2 weight percent, and less than or equal to 2 weight percent of MgO; wherein the grain diameter of the aluminum chromium slag is 0.1 mm-5 mm.

4. The process for producing metallic chromium by using aluminum-chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace according to claim 1, which is characterized by comprising the following steps: the main chemical component Cr of the chromium oxide₂O₃Not less than 99 wt%; the grain diameter of the chromium oxide is less than or equal to 200 meshes.

5. The process for producing metallic chromium by using aluminum-chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace according to claim 1, which is characterized by comprising the following steps: the diameter of the mixing material rod is 10 mm-50 mm, and the height of the mixing material rod is 10 mm-50 mm.

6. The process for producing metallic chromium by using aluminum-chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace according to claim 1, which is characterized by comprising the following steps: the diameter of the explosion-proof fiber is less than or equal to 0.5mm, and the length of the explosion-proof fiber is 10-15 mm; the softening and shrinking temperature of the explosion-proof fiber is 100-130 ℃.

7. The process for producing metallic chromium by using aluminum-chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace according to claim 1, which is characterized by comprising the following steps: the carbonaceous raw material in the step (1) and the step (2) comprises at least one of petroleum coke, graphite and carbon black.

8. The process for producing metallic chromium by using aluminum-chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace according to claim 1, which is characterized by comprising the following steps: and (3) when the temperature is continuously increased in the step (2), the temperature increasing speed is 10-20 ℃/min.

9. The process for producing metallic chromium by using aluminum-chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace according to claim 1, which is characterized by comprising the following steps: the mass ratio of the aluminum chromium slag to the carbonaceous raw material in the step (1) is 100: (3-4).

10. The process for producing metallic chromium by using aluminum-chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace according to claim 1, which is characterized by comprising the following steps: when the three-phase arc furnace is used for smelting in the step (1), the smelting temperature is 1900-2000 ℃, and the smelting time is 4-8 hours.

Technical Field

The invention relates to a process for producing metal chromium by using aluminum chromium slag, in particular to a process for producing metal chromium by using aluminum chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace.

Background

The smelting of metal chromium uses chromite and the like as main raw materials, and comprises the steps of oxidizing roasting, leaching sodium chromate, preparing chromium hydroxide from the sodium chromate, precipitating, washing and filtering to obtain solid chromium hydroxide, calcining the chromium hydroxide in a rotary kiln to obtain chromium oxide, and finally preparing the metal chromium from the obtained chromium oxide by an aluminothermic reduction method.

CN 105568004A discloses a method for smelting metal chromium from aluminum chromium slag, which comprises the following steps: uniformly mixing aluminum-chromium slag with the particle size of less than or equal to 10mm and petroleum coke with the particle size of less than or equal to 10mm, drying the mixture in a drying kiln until the water content is less than or equal to 0.5%, adding the mixture into a three-phase electric arc furnace for smelting, carrying out high-temperature smelting, transferring liquid chromium carbide at the bottom of an electric arc furnace hearth into a plasma electric arc furnace, introducing oxygen into the hearth of the plasma electric arc furnace, adding calcium oxide and calcium fluoride serving as a slagging agent, introducing argon serving as protective gas into the plasma electric arc furnace after the high-temperature smelting, adding aluminum particles for continuous smelting to obtain qualified liquid metal chromium, pouring the liquid metal chromium into a sand shell mold, naturally cooling, removing impurities on the surface, and crushing to obtain the metal chromium. The method can obtain the metallic chromium with the purity of 96 wt% -99 wt%. However, the method needs to transfer the high-temperature molten chromium carbide into the plasma arc furnace in the three-phase arc furnace, and meanwhile, the operations of introducing protective gas, adding aluminum particles in the smelting process, introducing oxygen and the like are needed, the process is complex, and the three-phase arc furnace and the plasma arc furnace are high-power thermal equipment, so that the process cost is high.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and aims to provide a process for producing metal chromium by taking aluminum chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace, which has low cost, simple process and high product extraction rate.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a process for producing metallic chromium by using aluminum-chromium slag as a main material and performing vacuum decarburization in a vacuum sintering furnace comprises the following steps:

(1) mixing the aluminum chromium slag and the carbonaceous raw material, putting the mixture into a three-phase electric arc furnace for smelting, naturally cooling, and separating out lower-layer chromium carbide;

(2) grinding the chromium carbide obtained in the step (1) into particles with the particle size of 80-150 meshes, and uniformly mixing the chromium carbide, chromium oxide, explosion-proof fiber, a carbonaceous raw material, methyl cellulose and water according to a mass ratio of 70: (20-40), 70: (0-2) and 70: (0-4) and 70: (0-2) and 70: (0-2), pressing into a cylindrical mixed material rod, placing the cylindrical mixed material rod in a vacuum sintering furnace, preserving the heat for 2-3 hours at the temperature of 25-70 ℃, and reducing the vacuum degree to 10^{- 1}And (4) continuously heating to 1300-1500 ℃ below Pa, carrying out vacuum sintering for 10-30 hours, and cooling along with the furnace to obtain the metal chromium.

More preferably, the mass ratio of the chromium carbide to the chromium oxide to the explosion-proof fiber to the carbonaceous raw material to the methylcellulose to the water is 70: (35-40), 70: (1.5-2) and 70: (3-4) and 70: (1.5-2) and 70: (1.5-2).

Preferably, the aluminum chromium slag particles are slag generated by smelting ferrochrome, and the main phases are corundum phase and aluminum chromium solid solution phase; the main chemical components of the aluminum chromium slag particles are as follows: al (Al)₂O₃75 to 85 weight percent of Cr₂O₃10 to 15 weight percent of CaO, less than or equal to 3 weight percent of CaO, Fe₂O₃Less than or equal to 2 weight percent, and less than or equal to 2 weight percent of MgO; wherein the grain diameter of the aluminum chromium slag is 0.1 mm-5 mm.

Further preferably, the chromium oxide contains Cr as a main chemical component₂O₃Not less than 99 wt%; the grain diameter of the chromium oxide is less than or equal to 200 meshes.

More preferably, the mixing bar has a diameter of 10mm to 50mm and a height of 10mm to 50 mm.

Preferably, the diameter of the explosion-proof fiber is less than or equal to 0.5mm, and the length of the explosion-proof fiber is 10-15 mm; the softening and shrinking temperature of the explosion-proof fiber is 100-130 ℃.

As a further preference, the carbonaceous feedstock in step (1) and step (2) comprises at least one of petroleum coke, graphite, carbon black.

Further preferably, when the temperature is further raised in the step (2), the temperature raising rate is 10 to 20 ℃/min.

Preferably, the mass ratio of the aluminum chromium slag to the carbonaceous raw material in the step (1) is 100: (3-4).

More preferably, in the step (1), when the three-phase arc furnace is used for smelting, the smelting temperature is 1900 to 2000 ℃, and the smelting time is 4 to 8 hours.

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

1. the raw materials used in the invention are low in price, and the aluminum chromium slag belongs to industrial solid waste and has environmental hazard.

2. The invention does not need special production equipment and treatment means, saves labor resources and has simple process flow.

3. The invention utilizes the carbonization reaction between the aluminum chromium slag and the carbon element and the difference of the specific gravity of the reaction product to realize the high-efficiency separation of the chromium element and the aluminum element in the aluminum chromium slag.

4. The present invention utilizes chromium carbide and Cr₂O₃The decarburization-deoxidation reaction is carried out to realize the preparation of the metal chromium.

5. The invention presses the material into a cylinder, which is beneficial to the discharge of gas, and utilizes the high-temperature loss of the explosion-proof fiber to generate a gas channel, thereby being beneficial to the implementation of decarburization-deoxidation reaction, and the prepared chromium metal has no unreacted area and high product extraction rate.

The chromium metal prepared by the invention is determined as follows: the Cr content of the metal chromium is 91-95 wt%.

Detailed Description

The invention is further described with reference to specific embodiments, without limiting its scope.

In order to avoid repetition, the raw materials related to this specific embodiment are uniformly described as follows, and are not described in detail in the embodiments:

a. the aluminum chromium slag particles are slag generated by smelting ferrochrome, and the main phases are corundum phase and aluminum chromium solid solution phase; wherein, the main chemical components of the aluminum chromium slag particles are as follows: al (Al)₂O₃75 to 85 weight percent of Cr₂O₃10 to 15 weight percent of CaO, less than or equal to 3 weight percent of CaO, 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 0.1 mm-5 mm;

b. main chemical component Cr of chromium oxide₂O₃Not less than 99 wt%; the grain size of the chromium oxide is not more than 200 meshes;

c. the diameter of the explosion-proof fiber is less than or equal to 0.5mm, and the length is 10 mm-15 mm; the softening and shrinking temperature of the explosion-proof fiber is 100-130 ℃;

d. the carbonaceous raw material comprises at least one of petroleum coke, graphite and carbon black.