Recent Developments in Basic Gunning of Electric Furnaces

Summary

These examples show that considerable dollar savings can be made by using newly developed gunmixes, equipment, and techniques. However, it is well to remember that gunned refractory installations are dependent, to a very great extent, on how they are installed.

Brick performance in a particular application can be predicted with a reasonable degree of accuracy based on the brick’s physical and chemical properties and the assumption that a competent bricklaying crew will install them in a workmanlike manner. Brick MgO level, silica content, porosity, density, modulus of rupture at various temperatures, etc. can all be determined before installation with assurance that these values will hold true in the installed brick.

Gunned installations, on the other hand, for their in-place properties are dependent on the mix, the equipment, and the technique used to put them in place. The refractory supplier builds into the mix the desired grain chemistry and mineralogy and provides a bonding system to hold it together if properly installed. Proper gunning equipment and gunning technique must be used to put the material where needed and to develop optimum properties in such vital areas as density, porosity, and strength.

The performance of a gunmix depends at least 60% on how well it is installed.