Since the 1950s, steel has been one of the indispensable and important basic materials in China's economic construction and national economic development. The quantity of steel and
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1 Overview of iron and steel smelting and refractory materials
1.1 Introduction to Iron and Steel Smelting
The steel metallurgical process that we are familiar with is usually referred to as steel smelting. According to the carbon content, industrially produced iron is divided into pig iron (carbon content greater than 2%) and steel (carbon content less than 2%). The core and key of steel smelting lies in the operation and application of the electron beam melting furnace, and the electron gun is the core of the electron beam melting furnace. The electron gun includes the gun head (usually composed of filaments, cathodes, anodes and other components), focusing coils, deflection coils, and so on. At this stage, the more commonly used iron and steel smelting operators are more willing to use blast furnace ironmaking, and use the direct reduction ironmaking method and the blast furnace ironmaking method separately. Steelmaking is mainly made from blast furnace smelting pig iron, sponge iron and scrap steel. It is made by direct reduction ironmaking and refined into steel by different methods. The basic production process is to smelt iron ore into pig iron in an iron smelting furnace, and then use pig iron as a raw material to make steel by various methods and cast into steel ingots or continuous casting billets.
1.2 Introduction to refractory materials
Refractory materials belong to the category of inorganic non-metallic materials. Their refractoriness is higher than 1580°C. The fire resistance refers to the celsius temperature of the refractory cone sample. The high temperature resistance of the sample will not soften and melt without load. Refractory materials are widely used in metallurgy, chemical industry, petroleum, machinery manufacturing, silicate, electric power and other industrial fields. The utilization rate of refractory materials is the largest among materials in the metallurgical industry, accounting for 50% to 60% of the total output. Refractory materials are widely used in various fields of the national economy, such as steel, non-ferrous metals, glass, cement, ceramics, petrochemicals, machinery, etc., and are essential materials for guaranteeing materials.
2 New technologies for iron and steel smelting
2.1 Distributed control system fluctuating temperature stable control technology
The temperature of iron and steel smelting is an object that changes with time and cannot be controlled linearly. It is difficult to achieve quantitative operations using a complete and accurate model during actual operations. To a certain extent, mathematical model technology cannot obtain precise control results. Therefore, the relevant operators adopted a new distributed control system, that is, the fluctuating temperature stability control technology of the decentralized control system in steel smelting.
Distributed control system fluctuating temperature stability control technology In the actual operation process, PC is used as the upper computer for overall system control and scheduling, and PLC is used as the lower computer to facilitate monitoring of temperature changes in the electron beam melting furnace. In addition, it is also equipped with corresponding supporting thermocouples and other components to jointly complete the task of stabilizing the fluctuating temperature of the distributed control system. The operating system of the distributed control system fluctuating temperature stability control technology is a relatively classic conventional DCS system. In actual operation, uncontrollable unexpected conditions rarely occur. When the main computer of the operating system encounters unexpected conditions or failures, In a short period of time, it can still rely on the lower-level computer for independent operation, and within a certain range, it will not have a great impact on the overall operation of the system. During the operation of the DCS system, the temperature in the smelting furnace fluctuates due to the interference of the external environment. In order to ensure the smelting quality of the product, the fluctuating temperature needs to be controlled stably. After starting the control, the PC will receive the corresponding signal, and the PC will set the temperature value in the furnace.
2.2 Energy-saving technology
After decades of development and changes, my country's economic and social environment has undergone earth-shaking changes, which are indispensable for the important role played by steel. Today, we are still inseparable from the consumption and use of steel when we carry out social labor production and national economic construction. With the growth of my country's industrial sector, the total consumption of steel is also increasing. The amount of technical power and various materials consumed by steel smelting is almost unpredictable. At present, my country's iron and steel industry consumes too much energy. Without energy-saving technologies, the existing resources and energy utilization are under tremendous pressure. This requires us to take energy-saving and emission reduction as an important part of the steel smelting process. In the actual operation of smelting iron and steel, there are many energy-saving methods that can be applied by incorporating energy-saving technologies into actual operations. For example, converter metallurgical pure steel technology, scrap preheating electric arc furnace, etc., these energy saving methods are widely used by relevant operators. In recent years, in our country, the integration of energy-saving methods in the actual operation of smelting steel has played a significant role. While saving energy, it also played a role in reducing costs. Nowadays, my country is facing severe energy problems, which in turn imposes stricter requirements on the steel production industry. Therefore, the promotion and application of energy-saving technologies is a general trend.
2.3 Environmental technology
With the development of science and technology, the methods and methods of steel smelting have undergone great changes. The advanced technology and products of the modern international steel industry have achieved relatively strong development in the direction of serialization, compactness, and specialization. However, the main processes of steel smelting are still inseparable from exploration, mining, metallurgical furnaces, forging or rolling. The most important raw material for the metallurgical industry is iron ore mined from deposits. The higher the iron ore content, the fewer raw materials used to produce iron and the shorter the time. Therefore, improving the quality of iron ore is an important direction for the development of environmental protection technology. The steel industry is a resource-intensive, energy-intensive and highly polluting industry. In order to achieve high-efficiency production with the least resource consumption, the best way is quality control to minimize the damage to the environment. This requires the integration of environmental protection technology with the steel smelting process, strengthening the optimization of the process, and realizing the reuse of resources. Currently, the more common environmental protection technologies include: high-efficiency continuous casting technology, dry quenching (CDQ) technology, coal humidity control technology, scrap steel preheating electric arc furnace technology and so on. The above-mentioned technologies can help relevant personnel adapt to environmental changes in the process of smelting steel and deal with resource, energy and even environmental issues.
2.4 Iron bath smelting reduction technology
The iron bath smelting reduction technology is a new member of the modern steel smelting technology family. This technology can more effectively control the content of other non-metallic impurities in the steel, and can also improve the purity of the steel. In recent years, the iron bath smelting reduction technology has been developed and improved, and the technical indicators of the iron bath smelting reduction degree are getting higher and higher. Therefore, the quality of steel can be further improved. The first step of iron bath smelting reduction technology must create a model, and then use control equipment to completely mix the molten pool in the steelmaking furnace, so that the temperature and sleep time in the furnace can be reasonably controlled to avoid unnecessary consumption and reduce blowing The number of furnaces, so that energy savings can be achieved and unnecessary energy loss can be avoided.
2.5 Scrap smelting technology
Scrap smelting technology uses electric arc furnaces in the smelting process to generate high thermal and chemical energy, but after proper research, it can be found that the oxidation reaction in the steelmaking furnace is still continuing, and the hotter and hotter gas can be discharged through the exhaust gas. . In the process of smelting steel, the heat released by the flue gas accounts for a large part of the total energy consumption. If this problem can be controlled, the energy-saving effect of steel smelting is bound to be significantly improved. The core of the electric arc furnace used to preheat scrap is to use the waste gas generated during the steel smelting process to preheat the steel raw materials and reduce energy consumption. According to relevant data, if the temperature of the raw material rises by 50°C, 10 kWh/ton of energy can be saved. Therefore, it is easy to understand that the promotion of this technology has unimaginable development prospects.
3 The impact of new iron and steel smelting technologies on refractories
3.1 Ironmaking technology and refractory materials
Ironmaking technology still uses relatively more refractory materials. For example, iron bath smelting reduction technology requires frequent use of refractory materials during actual operation. In recent years, the increase in iron bath smelting reduction and the decrease in direct reduction pig iron smelting. In order to achieve industrial production, the optimization of iron smelting technology and new technology has also put forward new requirements for refractory materials, such as improving the corrosion resistance of corundum materials, etc. .
3.2 Steelmaking technology and refractory materials
The development of steelmaking technology has caused certain changes in the structure of steelmaking refractories. Compared with the blast furnace refractory material process, the scrap steel smelting technology in the smelting process requires a higher melting point refractory material in the recycling process to prevent the corrosion of FeO, which requires high heat resistance and a better melting zone. The refractory materials in this area are mainly composite materials.
3.3 The requirements of steel technology for future refractory materials
In order to be able to further adapt to the requirements of the modern steel industry, adhere to the path of independent innovation and development, develop new materials and new products, the following aspects should be paid attention to in the research and development work: First, strengthen the The development and utilization of non-carbon materials and alkali-fired bricks; second, to further promote the research of refining technology and ultra-pure steel, and the integration of metallurgical energy-saving refractory materials; third, to strengthen interdisciplinary and nanotechnology in refractory materials The application of research; fourth, the development of modified and homogeneous materials and comprehensive utilization of mineral resources and so on.
4 Conclusion
In summary, based on the above analysis and introduction of new steel smelting technology and its impact on refractory materials, it can be known that the current development of steel smelting technology and refractory materials in China has reached the international advanced level and has entered International advance list. The cooperation of new steel smelting technology and refractory materials has been able to meet the supply of steel quantity needed for our country's economic construction. The development of the steel industry requires long-term efforts and maintenance. From the current situation, the development of steel smelting and refractory materials in China still has broader prospects and is worth looking forward to.
Zhengzhou SNR Refractory Co.,Ltd are professional in producing different kinds of refractory materials for glass industry.Any demands,please don't hesitate contact with me.
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