Three common ways to reduce the high temperature erosion of magnesium carbon brick

       ZHENJIN REFRACTORIES deep refractory industry for 37 years, according to the daily work of practice and experience, the current common method to reduce the high temperature erosion of magnesium carbon bricks can be summarized as the following three points.

1、Choose high-quality materials with stable composition to improve the erosion resistance, thermal shock resistance and structural spalling resistance of the materials.

      Choose high purity and high quality electrofused magnesium sand, because it has the advantages of large grain size, high density, low chemical activity, high erosion resistance, and at the same time can resist the self-destruction reaction with carbon at high temperature and thus inhibit the erosion of MgO particles by slag. Secondly, increase the MgO content and reduce impurities, especially limit the SiO₂ content, and reduce the silicate phase in the structural components of MgC brick, so that the side reactions at high temperature, such as the reaction between SiO₂ and graphite, can be reduced to avoid the oxidation of carbon. In addition, increasing the degree of crystallization of MgO crystals can prevent the dissolution caused by the transformation of MgO grain boundaries into liquid phase at high temperature and stop the further penetration of slag into magnesia carbon bricks. Improve the graphite purity can also increase the slag resistance of magnesia carbon brick, because with the increase of graphite purity, magnesia carbon brick thermal shock resistance increased, high temperature flexural strength also increased significantly. Therefore, generally to use graphite with carbon content greater than 95%, as the graphite purity increases, other impurity components reduce, the silicate phase contained in less, in the alkaline slag SiO₂ will occur with the carbon in magnesia carbon brick decarburization reaction to form decarburization layer, but also with magnesium oxide, ferrous oxide, etc. to form a low-melting phase to accelerate the dissolution of magnesia carbon brick. Finally, to the magnesia carbon brick add an appropriate amount of antioxidant, and the choice of high-quality thermosetting bonding agent can also improve the high temperature performance of magnesia carbon brick.

2、Optimize the composition of smelting slag.

       For magnesia carbon brick refractories, should increase the content of MgO in the slag as much as possible, so that the MgO in the slag reaches saturation state thus reducing the dissolution of MgO. Because MgO is alkaline oxide, increase the slag alkalinity can reduce the chemical reaction of slag and magnesium oxide to reduce the chemical erosion of magnesia carbon brick. Reduce the content of FeO or other elements that may occur chemical reaction in the slag can reduce the oxidation of slag to MgO and graphite and other reactions.

3、 Adopt external means

       In the magnesia carbon brick surface through external means to form a protective layer, prevent magnesia carbon brick and slag contact, prevent high temperature steel / slag to the refractory internal physical penetration and chemical erosion, such as sputtering slag protection furnace. Can also be through the electric field, magnetic field, ultrasonic field and other external field action on the magnesium carbon brick refractory protection, which external electric field cathodic protection method is a malefactor in recent years to study the refractory material against high temperature steel / slag erosion of new technology, has attracted widespread attention of scholars.