In the last article, we discussed the first problem in the use of magnesia-calcium carbon bricks. Today we will talk about the second problem. This problem is about binder.
Nowadays, phenolic resin is widely used as a binder for carbon-containing refractories due to its high carbon residue rate and high bonding strength. , the general phenolic resin is no longer suitable for magnesium calcium carbon refractories in Magnesite Bricks Factory. Instead, only anhydrous phenolic resins that do not contain free water can be selected. The anhydrous phenolic resin that has removed free water has more problems than the general phenolic resin. Due to the loss of free water, the fluidity of the anhydrous phenolic resin is significantly reduced, and it even needs organic solvents such as anhydrous alcohol and ethylene glycol to be dispersed before use, which brings a great deal to the mixing process. inconvenience. The storage of anhydrous phenolic resin also has the phenomenon of self-hardening of the resin surface after a long time. The degree of this phenomenon is directly related to the temperature of the resin storage environment and the degree of resin sealing in Magnesite Bricks Factory. It is called the phenomenon of aging hardening. It directly affects the use effect and storage time of the resin.
However, anhydrous phenolic resin is the same as ordinary resin in that it is relatively stable and will not decompose before 250 ℃, and when the temperature reaches 300 ℃, the thermal decomposition of the resin begins to gradually become obvious, which is the inherent characteristic of phenolic resin, and it is almost difficult to change . But such an inherent characteristic of thermal decomposition causes another problem in CaO-containing refractories in Magnesite Bricks Factory. Anhydrous phenolic resin does not contain free water, but as a macromolecular organic compound, anhydrous phenolic resin must contain partially locked water and hydrogen-containing functional groups, and anhydrous resin will inevitably generate water vapor when thermally decomposed. From the thermodynamic calculation, it can be known that the hydration of CaO will exist before 510 ℃, then this leads to another serious problem, the hydration of CaO caused by the self-cracking process of the anhydrous phenolic resin in the magnesium-calcium-carbon refractory in Magnesite Bricks Factory.
Therefore, it is necessary to verify and study the effect of the cracking behavior of anhydrous resin on the properties of magnesia-calcium carbon bricks in Magnesite Bricks Factory, and it is necessary to find a reasonable method to improve this problem.
