Process and device for smelting chromium irons and chromium-containing molten iron by using chromium ore powder

Abstract

The invention relates to a process and a device for smelting chromium irons and chromium-containing molten iron by using chromium ore powder, which belongs to metallurgical industry steel-making raw material. The process comprises the following steps: mixing chromium iron containing raw materials with reducing agent, solvent and catalyst to prepare ultra fine powder, mixing to make pelletizing materials, sending the pelletizing materials into a reducing furnace, obtaining chromium irons pellets after the reduction reaction, and directly adding reduced pellets into a lining electroslag furnace for being smelted into the chromium-iron alloy or the chromium-containing molten iron. The device comprises an internal-external heating vertical reducing furnace, a lining electroslag furnace and a residual heat recovery system. The invention has the advantages that: firstly, the reduction temperature is low, the speed is high, the energy consumption is reduced, the production cost is lowered, the production efficiency is high, and the uniformity of the quality is good; secondly, the degree of mechanization is high, the procedure is simple, the yield is large, the mass production can be performed; thirdly, the waste of raw materials is reduced, the environment pollution is lowered; fourthly, the source of raw materials adopting the chromium ore powder and chromium-containing waste, the cost is low; fifthly, the waste resource can be recycled so as to save the resource consumption; and sixthly, the high-temperature pellets are directly smelted by adopting the lining electroslag furnace, the heat efficiency is high, the energy consumption is low, the material purity is high and the quality is good, and the device is simple with less investment.

Description

technical field [0001] The invention belongs to the field of metallurgy, and in particular relates to a process for smelting ferrochrome alloy and molten iron containing chromium with chrome ore powder, and equipment for realizing the process. technical background [0002] Ferrochrome is an iron alloy mainly composed of chromium and iron. It is an important raw material for the iron and steel industry. It has good corrosion resistance, high temperature resistance, wear resistance, and improvement of the physical, chemical, mechanical properties and quality of steel and castings. And improve, so that the steel has a high use value. Due to its good properties, it is widely used in high temperature alloys, corrosion-resistant alloys, special steels, high alloy steels, high-quality alloy steels, metal wear-resistant materials, foundry industry, non-ferrous metal industry, chemical industry and stainless steel and other fields. . Especially in the field of stainless steel, the ...

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Problems solved by technology

[0006] The above studies have increased the use of powdered ore to a certain extent and reduced production costs, but they have not been able to fundamentally solve the use of powdered chrome ore, and there are problems such as low metallurgical strength, difficult reduction, high production costs, large environmental pollution, and electricity consumption. High consumption, high reduction temperature, high energy consumption, low production efficiency, complex technology and other deficiencies have prevented it from being industrialized so far.

Moreover, the above-mentioned various chromium-containing pellet preparation processes all belong to the category of raw material pretreatment. For example, when producing ferroalloy or stainless steel chromium-containing hot metal, it needs to be heated and smelted again, resulting in large energy consumption and many processes.

In order to be able to directly produce ferrochrome alloy and molten iron containing chromium, a lot of research and development work has been carried out at home and abroad. The patent of Nippon Steel in Japan reported the technology of producing high-carbon ferrochrome by converter smelting reduction. This method first puts ferrochrome in a rotary kiln Intermediate pre-reduction, and then put into re-blowing converter for smelting reduction, the obtained molten iron contains Cr: 53%, C: 6.5%, Fe: 37%, S: 0.0015%, P: 0.0035%, but the process is long and can High consumption and cost, and pollute the environment

Chinese patent No. ZL93102123.5 discloses a process for smelting ferrochrome alloy by reductive sintering and agglomeration of powdered chrome ore. This process uses part of the flux in the sintering ingredients, sintering in a reducing atmosphere, cooling, magnetic separation, and pressing to produce block, and then put it into an electric arc furnace for smelting. This process requires secondary heating and high power consumption, and only high-carbon ferrochrome can be smelted.

Chinese Patent Application No. 200510093590.8 discloses a process for smelting medium-carbon ferrochrome in a one-step process using a submerged arc furnace. This process adds a certain proportion of SiO to chromite 2 , coke and dolomite, smelting medium-carbon ferrochrome in a submerged arc furnace, using the decarburization and reduction double-layer effect of silicon, to SiO 2 Replace part of carbon to reduce the carbon content in ferrochrome alloy. The raw material used in this process is block ferrochrome, and it is smelted by submerged arc furnace, which has high cost and low efficiency, and the content of P and S in the product is high.

Chinese patent application No. 200610023696.5 discloses a ferrochrome smelting shaft furnace and a smelting method. The method is to load the pre-reduced heat-fixed ferrochrome pellets, ore, and coke into the shaft furnace through a large bell and a funnel. After being preheated by hot air above 1250°C on the top of the furnace, it is smelted into chromium-containing hot metal at the bottom of the shaft furnace at 1530°C. This process uses shaft furnace smelting, although energy consumption is reduced and continuous production is possible, but it is different from Compared with electric arc furnace and induction furnace, there are the following disadvantages: 1. Low thermal efficiency; 2. Low temperature of molten iron; 3. Large fluctuations in the composition of molten iron; The carbon content is high. When it is used as stainless steel molten iron, it needs to be decarburized outside the furnace for a long time, which increases the subsequent process time and energy consumption.

[0007] When using chromium ore powder to prepare pellets and then reduce them to smelt chromium-containing hot metal, since chromium ore contains a large amount of Al 2 o 3 , MgO, SiO 2 , CaO, and the pellets contain unburned residual C, which will increase the power consumption during direct smelting. At the same time, due to the low temperature of slag, it is easy to cause poor fluidity of chromium-containing molten iron and slag, which affects the normal production

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