Refractories are used in numerous industries, from steel to energy and glass. Without technological advances in refractories, industrialization in its present form after the Industrial Revolution would not have existed.
The discovery and mastery of fire is an important step in human evolution. Fire means more than just a new way of warming and preparing food. The use of fire has also had an impact on the development of human society and culture. New tools can be produced by casting, firing, and molding various materials. The high-temperature process has been known for more than 4,000 years.
Refractory technology began in the Iron Age (2000 BC). Charcoal was used in the furnace to produce iron by reducing iron ore with extreme heat. Furnaces used for iron making had a very basic refractory lining, usually composed of amorphous refractory clay, carbon-added composite materials and silica, although blocks cut from natural stone or refractory bricks were also used.
In the 18th and 19th centuries, refractory technology made great strides. Many industries began to use this new technology, prompting people to label the "smokestack industry". The furnace used to manufacture steel during this period has the following characteristics:
Coke blast furnace: Use coke instead of coal as a reducing agent and heat source.
Heat furnace: Use a regenerative heat exchanger to provide hot air for the blast furnace.
Coke coal open furnace: Use Gas replaces coal and regenerative heat exchangers, allowing you to use your own waste heat.
Converter: A steelmaking furnace that burns impurities in cast iron with air blown from the bottom.
Fireclay brick, which evolved presumably from ancient earthenware brick, represents most refractory materials before the industrial revolution; during this period, several new materials were developed. However, the development of new refractory materials cannot fully meet the increasingly demanding requirements of various functions of the endless new kilns.
In the 20th century, the United States became the world's center for steel production. Despite various wars, advances in refractory materials during this period include:
Many new forms of foams and oxide-free refractory materials have been developed.
Refractories have been developed for use in other industries such as galvanized bricks for the glass industry.
Silicon carbide bricks for ceramic firing. Test procedures for fire-resistant cabins are standardized and new results are published in scientific journals.
Post World War II
After World War II, refractory technology has been continuously refined and improved. Since the Industrial Revolution, the most important technological advances in most industries have occurred in developed countries after World War II. Conditions and the development of new materials have been established. On the other hand, due to the increase in the size of the furnace, the lining and maintenance need to save labor, and the service life of the lining is longer, thereby improving the production efficiency, and the requirements for refractory materials have also become diversified. High-pressure and high-temperature blast furnaces are widely used, the performance of various refractory materials is clearer, and the material design has also been improved to increase efficiency. Other innovations include:
higher-purity added carbon composite materials
introduction of new products such as zirconium bricks for cast ladle
introduction of magnesia-carbon bricks for converters which have become the mainstay of refractory materials
recycling of waste refractory materials to reduce the environmental burden
After the oil crisis
The two-phase oil crisis in the 1970s, directly and indirectly, had an extremely serious impact on refractory technology. At the same time, environmental problems related to substances such as hexavalent chromium and coal tar have become serious problems. Therefore, since the 1970s, resource conservation, energy conservation, and environmental protection have recently been included in the evaluation criteria of refractory technology, as well as the field of steel technology.
Considering the new commercial awareness of the business situation, refractory technology quickly responded to the new requirements of steel producers for the improvement of steel quality and higher added value, as well as the new requirements for reducing costs and increasing productivity. Focusing on refractory materials and focusing on different related aspects, a comprehensive knowledge system covering the fields of line repair methods (flame gun repair, etc.) and furnace lining design (heat preservation, refrigeration, etc.) has been formed. Monitoring and measurement (furnace lining monitoring system, etc.), and furnace operation for furnace lining protection (slag control, etc.).