阅读说明：本技术 一种循环利用密闭矿热炉尾气生产高碳铬铁的工艺 (Process for producing high-carbon ferrochrome by recycling tail gas of closed submerged arc furnace ) 是由 陶静 陶旭 于 2020-05-18 设计创作，主要内容包括：本发明提供了一种循环利用密闭矿热炉尾气生产高碳铬铁的工艺,包括如下步骤：1)铬铁矿球团的制备；2)将预处理后的密闭矿热炉尾气从下方送入反应竖炉,将铬铁矿球团从上方加入反应竖炉,矿热炉尾气与下降的铬铁矿球团接触后发生还原反应,同时铬铁矿球团中的碳在热状态下也发生还原反应,生成金属化球团；3)将生成的金属化球团送入密闭矿热炉中加入熔剂和还原剂熔融,渣铁分离后制得高碳铬铁,产生的密闭矿热炉尾气进入到步骤2)中经预处理后循环利用。该工艺循环利用了密闭矿热炉尾气,使成品焦炭的使用量减少、电耗降低了,生产能力提高,从而节约了资源、能源,改善了环境,提高了产品质量。(The invention provides a process for producing high-carbon ferrochrome by recycling tail gas of a closed submerged arc furnace, which comprises the following steps: 1) preparing chromite pellets; 2) sending the pretreated tail gas of the closed submerged arc furnace into a reaction shaft furnace from the lower part, adding the chromite pellets into the reaction shaft furnace from the upper part, carrying out reduction reaction after the tail gas of the submerged arc furnace is contacted with the descending chromite pellets, and simultaneously carrying out reduction reaction on carbon in the chromite pellets in a hot state to generate metallized pellets; 3) and (3) sending the generated metallized pellets into a closed ore-smelting furnace, adding a fusing agent and a reducing agent for melting, separating iron slag to obtain high-carbon ferrochrome, and sending the generated closed ore-smelting furnace tail gas into the step 2) for pretreatment and recycling. The process recycles the tail gas of the closed ore-smelting furnace, reduces the usage amount of finished coke, reduces the power consumption, and improves the production capacity, thereby saving resources and energy, improving the environment and improving the product quality.)

1. A process for producing high-carbon ferrochrome by recycling tail gas of a closed submerged arc furnace is characterized by comprising the following steps:

1) preparing chromite pellets;

2) sending the pretreated tail gas of the closed ore-smelting furnace into a reaction shaft furnace from the lower part, adding the chromite pellets into the reaction shaft furnace from the upper part, carrying out reduction reaction after the tail gas of the closed ore-smelting furnace is contacted with the descending chromite pellets, and simultaneously carrying out reduction reaction on carbon in the chromite pellets in a hot state to generate metallized pellets;

3) and (3) sending the generated metallized pellets into a closed ore-smelting furnace, adding a fusing agent and a reducing agent for melting, separating iron slag to obtain high-carbon ferrochrome, and carrying out pretreatment on the generated closed ore-smelting furnace tail gas in the step 2) for recycling.

2. The process for producing high-carbon ferrochrome by recycling the tail gas of the closed submerged arc furnace according to claim 1, wherein the pretreatment of the tail gas of the closed submerged arc furnace comprises the following steps: tail gas conversion, purification and preheating.

3. The process for producing high-carbon ferrochrome by recycling the tail gas of the closed submerged arc furnace as claimed in claim 2, wherein the tail gas shift is to send the tail gas of the closed submerged arc furnace into a shift converter to shift part of CO in the tail gas of the closed submerged arc furnace into H₂Changing the gas to H₂And CO up to 1.5 by volume.

4. The process for producing high-carbon ferrochrome by recycling the tail gas of the closed submerged arc furnace according to claim 2, wherein the purification is to perform low-temperature methanol washing on the tail gas of the closed submerged arc furnace after the tail gas conversion is finished to remove acidic components in the gas.

5. The process for producing high-carbon ferrochrome by recycling the tail gas of the closed submerged arc furnace according to claim 2, wherein the preheating means that the tail gas of the closed submerged arc furnace, which is subjected to tail gas conversion and purification, is preheated to a temperature of more than or equal to 1000 ℃ by using the gas exhausted above the reaction shaft furnace.

6. The process for producing high-carbon ferrochrome by recycling the tail gas of the closed ore-smelting furnace according to claim 1, wherein in the step 1), the preparation of the chromite pellets refers to preparing the chromite pellets by adding screen coke and bentonite according to the requirements of chromite components and metallization rate, and grinding, wetting, pelletizing and drying the chromite, the screen coke and the bentonite.

7. The process for producing high-carbon ferrochrome by recycling the tail gas of the closed submerged arc furnace according to claim 6, wherein the metallization rate of the metallized pellets is required to be maintained at 60-70%.

8. The process for recycling the tail gas of the closed submerged arc furnace to produce the high-carbon ferrochrome according to claim 1, wherein the step 3) of feeding the metallized pellets into the closed submerged arc furnace means that the metallized pellets are continuously fed into the closed submerged arc furnace through a heat transfer device, and the temperature of the metallized pellets fed into the closed submerged arc furnace is kept above 600 ℃.

9. The process for producing high-carbon ferrochrome by recycling the tail gas of the closed submerged arc furnace according to claim 1, wherein in the step 3), the fusing agent is silica and the reducing agent is coke.

10. The process for producing high carbon ferrochrome by recycling the tail gas of the closed submerged arc furnace according to claim 9, wherein the silica and the coke entering the closed submerged arc furnace are preheated to a temperature of more than 600 ℃ in a preheating kiln at the top of the submerged arc furnace before entering the closed submerged arc furnace, and the heat source for preheating is the gas discharged from the upper part of the reaction shaft furnace.

Technical Field

The invention relates to a production process of high-carbon ferrochrome.

Background

Chromium is the only element that determines the properties of stainless steel, and there are no stainless steels that do not contain chromium. In the fifth and sixty years of the last century, vacuum decarburization VOD technology and argon oxygen refining AOD technology are developed, and high-carbon ferrochrome becomes a raw material for stainless steel smelting. 1 ton of high carbon ferrochrome is required for producing 3.3 tons of stainless steel. In 1919, doctor norwegian, William Soderberg, invented a submerged arc furnace using self-sustaining electrodes. The traditional high-carbon ferrochrome process has been used for a century. The traditional high-carbon ferrochromium smelting is an electrothermal process of continuous smelting and intermittent tapping, wherein chromium ore is used as a raw material, silica is used as a slagging flux, and coke is used for carrying out carbon reduction in an electrically heated ore-smelting reduction furnace. In the traditional smelting method, each ton of high-carbon ferrochromium consumes 550 kg of coke and 3600 ℃ of 3200-.

Disclosure of Invention

The invention aims to provide a process for producing high-carbon ferrochrome, which recycles the tail gas of a closed submerged arc furnace, reduces the usage amount of finished coke used for producing the high-chromium carbon ferrochrome by one half, reduces the power consumption by one third, improves the production capacity by one third, saves resources and energy, improves the environment and improves the product quality.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a process for producing high-carbon ferrochrome by recycling tail gas of a closed submerged arc furnace comprises the following steps:

1) preparing chromite pellets;

2) sending the pretreated tail gas of the closed ore-smelting furnace into a reaction shaft furnace from the lower part, adding the chromite pellets into the reaction shaft furnace from the upper part, carrying out reduction reaction after the tail gas of the closed ore-smelting furnace is contacted with the descending chromite pellets, and simultaneously carrying out reduction reaction on carbon in the chromite pellets in a hot state to generate metallized pellets;

3) and (3) sending the generated metallized pellets into a closed ore-smelting furnace, adding a fusing agent and a reducing agent for melting, separating iron slag to obtain high-carbon ferrochrome, and carrying out pretreatment on the generated closed ore-smelting furnace tail gas in the step 2) for recycling.

Wherein, the pretreatment of the closed submerged arc furnace tail gas comprises the following steps: tail gas conversion, purification and preheating.

The tail gas conversion means that the tail gas of the closed submerged arc furnace is sent into a conversion furnace, and the part in the tail gas of the closed submerged arc furnace isConversion from CO to H₂Changing the gas to H₂And CO up to 1.5 by volume.

And the purification is to perform low-temperature methanol washing on the closed submerged arc furnace tail gas after the tail gas conversion is finished to remove acid components in the gas.

The preheating means that the tail gas of the closed ore smelting furnace which finishes tail gas conversion and purification is preheated to the temperature of more than or equal to 1000 ℃ by utilizing the gas exhausted from the upper part of the reaction shaft furnace.

In the step 1), the preparation of the chromite pellets refers to that the chromite pellets are prepared by adding screen coke and bentonite according to the chromite components and the metallization ratio requirements, and grinding, wetting, pelletizing and drying the chromite, the screen coke and the bentonite.

Preferably, the metallization rate of the metallized pellet is required to be maintained at 60-70%.

In the step 3), the step of feeding the metallized pellets into the closed ore heating furnace means that the metallized pellets are continuously fed into the closed ore heating furnace through a heat conveying device, and the temperature of the metallized pellets fed into the closed ore heating furnace is kept above 600 ℃. The heat conveying device is a storage tank with a refractory material lining, and metallized pellets produced by the reaction shaft furnace are put into the storage tank, transported to a storage bin above the closed submerged arc furnace and added into the furnace.

Preferably, in the step 3), the fusing agent is silica, and the reducing agent is coke.

Preferably, the silica and the coke entering the closed ore-smelting furnace are preheated to the temperature of over 600 ℃ in a preheating kiln at the top of the ore-smelting furnace before entering the closed ore-smelting furnace, and the heat source for preheating is gas discharged above the reaction shaft furnace.

The invention has the characteristics and the technical effects that:

1) the process changes the traditional chromite smelting reduction process, recycles the tail gas of the ore-smelting furnace of the closed furnace to reduce the chromite pellets, reduces the usage amount of finished coke by one half, and reduces the coking process pollution of a metallurgical plant;

2) the invention uses metallized pellet smelting, the charging material is hot-charged, and the consumption of the high-carbon chromium iron is reduced by one third.

3) The process increases the smelting capacity of the submerged arc furnace by one third;

4) the process used by the invention has less generation of particulate matters, sulfides and nitrogen oxides, and is clean and environment-friendly;

5) the reducing gas is purer, and the product produced by the process has less harmful impurities and good quality.

Drawings

The invention will be further explained with reference to the drawings

FIG. 1 is a flow chart of the production process according to the present invention;

Detailed Description