Fundamental Design of Steelmaking Refractories

9 Precast and Purging System

9.1 Introduction

Shaped (bricks) and unshaped (monolithics) are well-known refractory materials classifications. Bricks and monolithics have their pros and cons in refractory applications. Usually, shaped refractories can be further classified into two shapes, standard shapes and special shapes. Refractory manufacturers and consumers have recognized several standard shapes for different kilns and vessels. However, special shapes have specific designs and particularly suitable zones for kilns and vessels. Herein, a successful design depends on both the combination of shape and composition. The same shape may not be suitable for different vessels. Refractory bricks are almost always made by pressing technique and maintain uniform properties. High thermal strength, resistance to mechanical impact, and chemical attack impart excellent performance for critical regions like archways, belly-band areas, and many more. Predefined properties can be achieved by adjusting design, composition, and processing conditions. Special shapes have relatively critical shapes, and demand is relatively low compared to standard shaped refractories. It is most often made by hand molding and exhibits a variety of properties.

Unshaped refractories are commonly known as monolithic, and they form jointless lining with a tailormade shape in an application or predefined shape (precast). While considering the precast shape, castable is the prime concern to discuss. Castables made ...