Refractory material is the basic material of iron and steel industry. The refractory industry and the iron and steel industry promote each other and develop together. With China's economy entering the new normal, a series of new characteristics have emerged in the iron and steel industry: overcapacity, declining profitability, enhanced environmental and resource constraints, and more challenges in transformation and upgrading. The new normal of the iron and steel industry has put forward new requirements, new thinking and new changes for the refractory industry in the upstream of the industrial chain. In recent years, the performance and application of refractory materials have shown the characteristics of characteristics, diversification, refinement, high efficiency and low consumption. The development of refractory raw materials must be adapted to it, and it will also be diversified, enriched, and characterized. The new trend evolves.

1 multiple embodiment of new requirements for refractory raw materials

New requirements for 1.1 green environmental protection

1.1.1 Meet the requirements of clean steel smelting

Clean steel smelting puts forward new requirements for ironmaking, steelmaking related accessories and refractory materials to reduce and avoid pollution of molten iron and molten steel. Research and practice have found that aluminum-silicon refractory materials will pollute molten steel, magnesium materials do not pollute, and materials containing free CaO not only do not pollute, but also have the effect of cleaning molten steel. For this reason, sintering and electromelting magnesium calcium raw materials containing free CaO with good hydration resistance are favored.

In order to reduce the carbon pollution of carbon-containing refractory to molten steel, it is necessary to reduce the carbon content of carbon composite refractory. In order to eliminate the side effects of carbon reduction on thermal shock resistance and erosion resistance, it is necessary to introduce a dispersed carbon source. It promotes the development and production of various nano-carbon sources suitable for refractory materials such as carbon black, carbon nanotubes, and graphene.

In order to reduce the "back phosphorus" effect of tundish working lining on molten steel after refining, a low phosphorus or phosphorus-free binding system was developed. 2.1.2 Meet the "green" requirements of the iron and steel industry

In view of the carcinogenic effect of Cr6, chromium-containing refractory materials have been included in the country to restrict the use of products, with low chromium and chromium-free new materials to replace chromium-containing materials is imperative. Such as high-performance magnesia carbon bricks, magnesia aluminum spinel bricks, magnesia zirconium bricks, etc. used in RH refining furnace, can replace the traditional magnesia chrome brick.

Tar is widely used as a binder for the blast furnace outlet. In order to reduce the pollution of the environment in the process of production and use, people are encouraged to develop new environmentally friendly binders.

In order to reduce the harm of traditional aluminum silicate refractory fiber to the environment and human body in the process of production, processing, use and installation, post-treatment, biodegradable calcium-magnesium-silicon refractory fiber has been developed and used.

1.1.3 Meet the requirements of energy saving and emission reduction in iron and steel industry

As an industrial lining material, it is imperative to use energy-saving refractory materials. In recent years, the development and application of new energy-saving raw materials are: microporous structure lightweight mullite-quality raw materials, mullite hollow spheres, lightweight microporous sintered alumina, CA6-MA composite lightweight aggregate, olivine lightweight material, spinel lightweight material, nano-porous silica powder and its polymer.

1.2 development of economical refractory

At present, the refractory industry and steel industry related to the refractory raw material industry chain are in a downturn, and low-cost winning bid has become the direction of the supply chain relationship. On the other hand, some high-grade natural mineral raw materials such as high bauxite gradually depleted, ore grade decline and quality fluctuations increase, relying on high-grade raw materials to improve performance, cheap raw materials to reduce costs of technical configuration route gradually come to an end. Guided by this orientation, cheap and economical refractory materials and products will become a major trend.

Low consumption is the main development direction of economical refractory. The main direction to achieve low consumption of raw materials is to expand the use of natural raw materials, light burning materials and recycled materials. In order to ensure the high temperature volume stability of refractory materials, natural raw materials must be sintered or fused at high temperature to make them barren and tend to thermodynamic equilibrium as much as possible. This will lead to high energy consumption, but also a certain degree of capacity surplus, in a sense, resulting in invisible resources and energy waste. Non-equilibrium raw materials with lower sintering temperature than traditional sintering can be developed and applied, and even a certain amount of natural raw materials can be directly added to reduce the energy consumption of refractory materials to a certain extent.

Previous studies have shown that the addition of a certain amount of natural raw material castable has a good effect, the raw material after heating decomposition of the escape of gas to form a channel, help to improve the anti-burst performance. Adding raw coal gangue or light burning coal gangue to aluminum silicon castable, and generating in situ mullite after heating, can improve its thermal bending strength, load softening temperature, improve thermal shock resistance, and also help to realize the lightweight of heavy materials.

In the face of the gradual depletion of high-grade ore and the fact that low-grade ore is increasingly becoming the main source of raw materials, people must reconsider the scientificity, rationality and adaptability of raw materials and product indicators, and optimize the allocation of raw materials to make it more excellent and competitive. Consideration should be given to appropriately reducing the A12O3 content and bulk density of high-alumina refractory materials used in certain non-melt scouring and erosion sites, and relaxing the need for certain

Requirements for impurity content of aluminum and silicon refractory materials used in medium and low temperature parts.