The continuous and rapid development of high temperature industry and abundant refractory raw material resources have supported the golden development period of China's refractory material industry for many years, and also promoted the development of refractory raw material industry itself, which is manifested in the continuous increase of output, variety, performance and quality improvement. Refractory raw materials can be called the backbone of refractory products, and refractory products are interdependent and mutually promoted, the former ensures the realization of the characteristics of the latter, the latter provides a broad application space for the former. Magnesia carbon brick
At present, the application of refractory materials is characterized by characteristics, functionalization, diversification, refinement, high efficiency and low consumption, and the development of refractory materials must adapt to it. At the present stage, affected by economic downturn, sluggish demand, resource and environmental protection constraint increase and other factors, high temperature industry and refractory materials industry has entered a new stage of development to improve quality and efficiency, and the adaptability of refractory raw materials has also put forward new requirements beyond the traditional. At the present stage, the new demand of the user industry, the enhancement of resources and environmental protection constraint, and the development direction of the characteristic, integration, green and low consumption of refractory materials are the main factors leading to the diversification of the adaptability of refractory materials.
New requirements of user industry New technology, new process and new process of high temperature industry put forward new requirements for the performance and function of refractory materials. For this, refractory products must have performance and function of promotion or breakthrough. Accordingly, refractory raw materials must have new characteristics and new varieties to meet the new needs.
To meet the needs of clean steel smelting
To meet the needs of clean steel smelting. With the adjustment of the structure of iron and steel industry and the development of special steel, clean steel smelting technology has been widely adopted, and new requirements have been put forward for reducing the related auxiliary materials and refractories used in iron and steel making, as well as avoiding the pollution of molten iron and steel. It is found in research and practice that aluminum-silicon refractories will pollute molten steel, magnesium materials do not pollute, and materials containing free calcium oxide not only do not pollute, but also have the function of cleaning molten steel. The higher the content of calcium oxide, the more obvious the effect. For this reason, magnesia-calcium raw materials containing free calcium oxide which have good hydration resistance and electric fusion are favored.
It is necessary to reduce the carbon content of carbon composite refractories in order to reduce the carbon pollution of molten steel by carbon containing refractories. In order to eliminate the side effects of carbon reduction on thermal shock resistance and corrosion resistance, it is necessary to introduce the diffuse carbon source, which promotes the development and production of various nano carbon sources suitable for refractories, such as carbon black, carbon nanotubes and graphene.
Meet the requirements of "green" production
In addition to the requirements of clean steel, some other high temperature processes also require refractory materials do not pollute the bearing medium. For example, in view of the carcinogenic effect of Cr6+ on humans and animals, refractory containing chromium has been included in the Ministry of Environmental Protection restricted use of products, with low chromium and chromium free new materials to replace the chromium containing material is imperative. In recent years, China has been developing and applying Fe-Al spinel to replace Mg-Cr brick, and at the same time, new raw materials of Mg-Al - Fe composite spinel have also been synthesized and successfully applied in cement rotary kiln.
In order to reduce the harm of traditional aluminosilicate refractory fiber to the environment and human body in the process of production, processing, installation and post-treatment, biodegradable environment-friendly calcium-magnesium-silicon refractory fiber has been developed and used, and is becoming more and more popular.
To meet the requirements of high temperature industrial energy conservation and emission reduction
Greenhouse effect and haze weather increase, the social voice for high-temperature industry to achieve energy conservation and emission reduction is rising. As the lining material of industrial furnace, it is imperative to use the energy-saving refractory with better energy saving effect. In recent years, new materials that are beneficial to energy saving are developed and applied, such as lightweight mullite materials with microporous structure, mullite hollow spheres, lightweight microporous sintered alumina, Ca6-MA composite lightweight aggregate, olivine lightweight aggregate, spinel lightweight aggregate, nanoporous silica powder and its polymer, etc. If use micro porous lightweight mullite stone aggregate rocky hollow ball and mullite aggregate development around the volume density of 1.8 g/cm3 of high performance lightweight castable, can replace the volume density of 2.5 g/cm3 around with heavy use of castable, the magnesium reduction furnace was used to working lining, with annular heating furnace of steel rolling working lining and steel rolling heating furnace water Liang Lizhu binding of water cooling, and obtained satisfactory effect, lining the weight reduction, energy saving effect is obvious.
At present, the refractory material industry and the high-temperature industry related to the refractory raw material industry chain are in a downturn, and the low-price bid has become the direction of some enterprises. At the same time, some high grade natural mineral raw materials, such as high bauxite gradually exhausted, ore grade decline and quality fluctuations increase, by high-grade raw materials to improve performance, cheap raw materials to reduce the cost of technical configuration route gradually came to an end. The current situation urges us to adjust the direction of research and development, technical ideas and process routes, abandon the traditional design ideas, closely follow the pulse of The Times of low consumption, high efficiency and green, improve the utilization rate of resources and optimize the level of allocation, improve the cost performance of products. Under the guidance of this orientation, cheap and economical refractory raw materials and products will usher in more demands.
Low consumption is the main development direction of economical refractories. The main direction of realizing low consumption of raw materials is to expand the use and use range of natural raw materials, light burning materials and recycled materials. In order to ensure the high temperature volume stability of refractories, natural raw materials must be sintered or fused at higher temperatures to achieve fineness and tend to thermodynamic equilibrium state as far as possible. This will lead to high energy consumption, but also lead to a certain degree of capacity surplus, a sense of hidden resources and energy waste. The non-equilibrium raw materials with lower sintering temperature than the traditional sintering temperature can be developed and applied, and even a certain amount of natural raw materials can be directly added to reduce the energy consumption of the refractory materials to a certain extent.
It has been found that the non-equilibrium raw materials continue to have beneficial in-situ reactions during use, which will bring about some beneficial effects. The research results of High Temperature Materials Research Institute of Hechang University and Gengsheng Company show that the castable with a certain amount of natural raw material has a good effect, and the gas from the decomposition of raw material after heating forms a channel, which helps to improve the anti-burst performance. Adding raw coal gangue or lightly fired coal gangue to Al-Si castable to generate in-situ mullite after heating can improve its hot flexure strength, softening temperature under load, thermal shock resistance, and also help to realize the lightweight of heavy materials.
After the rich period of abundant resources, arbitrary exploitation, mining the rich and abandoning the poor, practitioners are more and more aware of the challenge of resource crisis. When the high-grade ore is gradually exhausted and the low-grade ore is becoming the main source of raw materials, it is necessary to reconsider the scientific nature, rationality and adaptability of raw materials and products, optimize the raw material allocation, and make it more excellent and competitive cost performance. It should be considered to reduce the A12O3 content and bulk density of high alumina resistant materials used in some non-melt scouring and erosion sites, and relax the requirements for impurity content of aluminosilicate resistant materials used in some medium and low temperature sites.
After use in recent years, the recycle of refractory and the utilization of waste refractory grows steadily, and recycling technology level gradually improve, renewable processing industry rise slowly, specialization, scale, systematic, standardized gradually mature, for the refractory industry provides a certain amount, quality and cheap, cost-effective reworked material, improve the refractory efficient utilization of resources, the level and the level of recycling. To a certain extent, this alleviates the tension of refractory raw material resources and promotes the development of refractory industry to the direction of low consumption, reduction and economy. In addition to the reuse of refractory materials after use, other industrial wastes should be expanded to become refractory materials for resource utilization, such as ferrochrome, ferrotitanium, steel waste residue, red mud, coal gangue and other wastes used as raw materials for fire materials.