Speed up the research and development of high quality synthetic refractory raw materials

At present, some developed countries in reducing the use of natural raw materials, and high purity synthetic raw materials continues to grow, the reason is the extensive use of raw materials for the synthesis of the unshaped refractory material increase in the proportion, and the use of natural raw materials of clay brick, high alumina brick, zircon brick production on the decrease. The users have higher requirements for the life of refractory materials, and the high purity synthetic materials can meet the needs in this respect.

The recent development of several representative synthetic materials:

1., using kaolin and industrial alumina as raw material, wet milling, vacuum extrusion, and then calcined at high temperature, Moris Ki clinker has good thermal and mechanical properties. It has a good application prospect in kiln furniture and amorphous refractory.

2. the same with kaolin and caustic magnesite as raw material, after grinding, vacuum extrusion into the ball, and then calcined at high temperature, can obtain the crystal growth of cordierite kiln clinker in good, having a good application prospect.

3. because of the development of clean steel, low carbon steel, high oxygen steel and stainless steel, the alkaline refractory containing free calcium has been paid more and more attention, for example, magnesium calcium clinker.

4. bauxite based fused corundum and bauxite based electrofusion mullite, bauxite based electrofusion mullite, zirconia and fused corundum zirconia, fused Magnesium Oxide, zirconia and other synthetic materials have also been developed rapidly.

5. it is worth mentioning that a spherical compact hollow synthetic mullite aggregate can be used in the production of amorphous refractory materials. The material is characterized by the thickness of the hollow shell, 0.2 millimeters to 5 millimeters, and the diameter from 1.5 millimeters to 40 millimeters. The surface can be smooth, smooth, rough and uneven, and the shell can be single or double layer. The surface prominent parts can be compact or empty. Therefore, the application of the castable can not only improve the insulation property of the material, but also reduce the volume density without destroying its strength.

Andalusite, sillimanite, kyanite raw materials.

Because of andalusite, sillimanite, kyanite in high-temperature phase mullite, mullite and the expansion coefficient is small, is conducive to improve the thermal shock resistance of the material. Adding Andalusite in the material, can form a thermal stress diffusion of many small gaps, caused by the expansion contraction in refractory internal stress release, so as to improve the thermal shock resistance of the material. The temperature of sillimanite completely MOS is higher, which is beneficial to improve the creep resistance of the products at high temperature. In addition, the volume expansion effect produced by mullite is also beneficial to high temperature resistance to creep.

Data show that using andalusite as raw material of red brick, the creep resistance is better than that of ordinary high alumina brick, corundum brick and most of the mullite brick. Therefore, it is very useful to use the "three stone" to improve the microstructure and thermodynamic properties of the aluminosilicate refractories.

The iron and steel industry developed rapidly with refractories

The material of refractory material used in blast furnace has a great change. The development of ceramic cups in blast furnace is becoming more and more common, but the ceramic cups in the production of blast furnace need to be applied with high corrosion resistant refractory materials to ensure the prolongation of their service life. In addition to changes in design, great changes have taken place in the material of refractories, such as microporous carbon bricks instead of ordinary carbon bricks to reduce the penetration of molten iron. The grouting method is used to repair the back lining of the blast furnace, which can effectively prevent the scour of the hot air flow of the back lining, thus prolonging the life of the blast furnace lining.

The converter uses a new water cooling technology in refractories. In converter steelmaking, a water cooling technology and suspension system are applied to the upper cone part and the lower carcass part of the converter shell respectively, so as to reduce the deformation of the converter body, prolong the service life of the converter lining and improve the productivity of the converter. The application of these new technologies impact the use of refractory material, the furnace life of converter increased to an average of 4000 or more, in addition to gunning, application of lime and dolomite as well as the application of slag splashing technology is not a problem, more than 10 thousand furnace furnace.

The focus of the submerged nozzle for continuous casting is determined. As a result of the development of the continuous casting system, the tundish has changed from the past transfer station to the present metallurgical container that affects the quality of the cast steel and increases the productivity of the cast steel. Therefore, many functional materials are gradually used in the tundish, such as the slag barrier, the impact plate, the filter, the argon blowing plug and so on.

Submerged entry nozzle is an important function refractory material for continuous casting. The research focuses on two aspects: first, improving the corrosion resistance of slag line, and the two is to reduce the adhesion of Al2O3 inside the wall. Adding ZrO2 content to 88% and silicified particle size distribution measures can reduce the thermal expansion rate and porosity of products, increase density and improve corrosion resistance.

The innovation direction of refractories for cement and glass industry

The production of cement in the world has increased from 8 billion tons in 1980 to 18 million tons in 2003, and it is expected to continue to grow at an annual average growth rate of 3.6% by 2020. The changes in the production process of the cement industry not only greatly improve the efficiency and production capacity of the cement production, but also put forward new requirements for the refractory. The fire-resistant material per ton of cement has fallen from the past 1.2 kilograms to the current 0.58 kilograms, and is expected to fall to 0.5 kilograms in 2005. In addition to traditional magnesia brick, magnesia chrome brick, high alumina brick, clay brick, low cement castable for cement kiln kiln head and tail pipe, elbow pipe, cooler and decomposer bottom has more obvious effect.

The main problem faced by refractories for glass industry is the development of low temperature melting. The development of the melting technology of arsenic free materials, the technology of total oxygen combustion and the technology of electric aid, put forward more stringent requirements for refractory materials.