Hello, welcome to the official website of Liaoning Hongyu Refractories Group Co., Ltd.
Liaoning Hongyu refractory Group Co., Ltd.
Address: two room village, Guan Tun Town, Dashiqiao, Liaoning, China
Web site: www.hy-ref.com
Contact: high general
Zip code: 115100
The scale graphite has the following characteristics
The melting point of 1. high temperature resistant graphite is 3850 and 50 C, and the boiling point is 4250 C. The mass loss of magnesia carbon brick is very small and the coefficient of linear expansion is very small, even after the high arc burning. The strength of graphite strengthened with the increase of temperature, and the strength of graphite increased by 2000 times.
2. electrical conductivity and thermal conductivity. The conductivity of graphite is twice higher than that of ordinary nonmetallic minerals. Thermal conductivity exceeds steel, iron, lead and other metal materials. The thermal conductivity decreases with the increase of temperature, and even at extremely high temperature, graphite is adiabatic.
3. lubricity. The lubricity of graphite depends on the size of graphite flake. The larger the scale, the smaller the friction coefficient, the better the lubrication performance.
4. chemical stability, graphite at room temperature has good chemical stability, acid, alkali resistance, organic solvent corrosion.
5. plasticity. Graphite has good toughness and can be rolled into thin sheets.
6. resistance to thermal shock. When graphite is used at high temperature, it can withstand the dramatic change of temperature without causing damage. When the temperature changes, the volume of graphite changes little, and no cracks are produced.
The binder plays a role in linking the matrix and particles. In the actual production and application process, the matrix and binder system are two weak links of magnesia carbon bricks.
The requirements for the bonding agent for the production of magnesia carbon bricks are
1. it has a certain viscosity and fluidity at room temperature, and has good wettability for magnesia and graphite.
2. bond can be further condensed in the heat treatment process, so that the product has a higher strength.
3. during heat treatment, the binder does not cause excessive expansion and shrinkage of the product, so as to avoid cracking.
4.C content is high, and the carbonaceous polymer after coking treatment has good high temperature strength.
In general, the binder used for producing magnesia carbon bricks is coal tar pitch, coal tar, special carbon resin, polyol, pitch modified phenolic resin, synthetic phenolic resin, etc.
The excellent performance of magnesia carbon brick depends on the existence of carbon in the brick. The oxidation of carbon in the process of use is easy to cause the deterioration of the product tissue, which makes the slag intruding into the bricks along the gap, eroding the Magnesium Oxide particles and reducing the service life of the magnesia carbon bricks. At present, oxidation resistance of magnesia carbon bricks is mainly improved by adding antioxidants.
The principle of selecting antioxidants
1. according to thermodynamic data and conditions of use, it is possible to determine the possible condensate phases and the vapor pressure of each vapor phase.
2. comparing the size of each condensed phase with oxygen affinity and the possibility of CO reaction.
3. analysis of the effect of various reactions on the microstructure of brick