In the existing steelmaking process, it is usually necessary to quantitatively invest some iron alloys with certain particle size (such as ferromanganese, ferrosilicon, ferromanganese, etc.) into the smelting furnace as additives to adjust the composition of the steel. The ferroalloy block is crushed and processed to the required particle size. Inevitably, a part of iron alloy powder will be formed. These powders cannot be directly added to the steel-making furnace for use (because the powder often floats on the surface of the molten steel, it is difficult to sink into the molten steel to deoxidize and cannot be evenly stirred), and improper storage will cause dust pollution. Generally, it can only be shipped back to the ironworks as waste material for reprocessing.
Due to the limited number of these ferroalloy powders, it is not economical to use a steel-making furnace for melting, and it is more appropriate to use an induction melting furnace. However, it is difficult to form an induction eddy current in ferroalloy powder in an induction melting furnace-it cannot be melted. In order to solve the recycling of ferroalloy powders, many steel-making manufacturers have made efforts and have no good plan.
The development is based on the following principle: under the action of an intermediate frequency electric field in an induction melting furnace, an inductive eddy current can be formed in the molten state or a bulk iron alloy with a certain volume, and the iron alloy powder is evenly dispersed in the metal (such as steel) or the iron alloy melt, which can be heated melt.
The smelting method of the induction melting furnace developed for the ferromanganese-silicon alloy is provided by the following process steps:
(1) First use metal blocks (preferably steel) or iron alloy blocks as raw materials to melt in an induction melting furnace to make a mother liquor, which preferably accounts for 1 / 4-1 / 5 of the furnace's internal volume,
(2) When the temperature in the furnace reaches the melting point of the iron alloy (1500-1600 ° C). Add the iron platform gold powder in batches at the same time, and stir with the iron rod at the same time to make the powder evenly distributed and mixed into the mother liquor. After the powder is completely melted, continue to add the iron alloy powder}
(3) Pour the molten iron alloy liquid into the corresponding casting mold. Cast into iron table nuggets or iron alloy balls suitable for steelmaking into the furnace particle size requirements, while retaining an appropriate amount of iron alloy melt in the induction melting furnace as the mother liquid for the next furnace smelting.
In order to improve the efficiency of smelting and reduce the generation of waste slag, different induction melting furnace lining materials should be selected according to different types of ferroalloys. There are roughly two types of lining materials for induction melting furnaces, one is acidic oxides such as silica (which can generate acids under appropriate conditions), and the other is basic oxides such as magnesium oxide (which can generate alkalis under appropriate conditions). . When smelting ferromanganese, ferromanganese, ferrosilicon and other ferroalloys, it is best to use alkaline materials such as magnesium oxide for the lining of the induction melting furnace. This is because manganese oxide, the low-cost oxide produced in the smelting process of these two types of ferroalloys, is alkaline, if acidic lining is used. It will react to form waste residues such as manganese silicate. Similarly, in the smelting of ferrosilicon alloys, acid linings such as silica are used in the induction melting furnace lining
It is expected that the use of alkaline lining will also react to generate waste residues such as magnesium silicate.
The smelting of iron alloys in induction melting furnaces is carried out in bulk, and it is easy to produce oxidative decarburization, that is, the oxygen in the air reacts with the carbon in the iron alloy melt to generate gas escape outlets. The stable structure composed of iron and carbon easily reacts with the lining material to form waste residue (manganese-containing salts). In order to prevent the harm caused by oxidative decarburization, after adding appropriate amount of ferroalloy powder every time and stirring it evenly, add carbon powder (such as graphite powder) into the furnace according to 1-2% of the weight of the ferroalloy powder and stir it evenly. Because the specific gravity of carbon is small, it mainly floats on the surface of the iron alloy melt in the furnace, which is equivalent to forming a protective layer, so that oxidative decarburization is mainly carried out here, reducing the impact on the melt, and thus slowing down.
Corrosion of lining materials.
The smelting method provided by the iron platform gold induction melting furnace developed and provided has the following advantages:
1. The iron alloy powder containing manganese and silicon is processed and recycled by this method. The processing technology is simple and no new equipment is needed. Each ton of iron platform gold can save more than 1,000 yuan, and the economic benefits are considerable.
2. Handle and process the iron alloy powder in a timely and convenient manner, save the cost of land occupation, greatly reduce the pollution of the dust to the environment, and use appropriate furnace lining materials, which can increase the recycling rate of the iron alloy powder from 80% to 90%, reducing the generation of waste residue And erosion of furnace tree materials.
4. Adding appropriate amount of ferroalloy powder and carbon powder alternately in the smelting process can also effectively reduce the generation of waste slag and the corrosion of the furnace lining material.
5. This smelting method can be operated continuously or produced intermittently.