often used in induction furnace linings are also monolithic, and sold and transported as a dry powder, usually with a magnesia/alumina composition with additions of other chemicals for altering specific properties. They are also finding more applications in blast furnace linings, although this use is still rare. Based on fusion temperature Refractory materials are classified into three types based on fusion temperature (melting point). Normal refractories have a fusion temperature of 15801780 °C (e.g. Fire clay) High refractories have a fusion temperature of 17802000 °C (e.g. Chromite) Super refractories have a fusion temperature of > 2000 °C (e.g. Zirconia) Based on refractoriness Refractoriness is the property of a refractory's multiphase to reach a specific softening degree at high temperature without load, and is measured with a pyrometric cone equivalent (PCE) test. Refractories are classified as: Super duty: PCE value of 33–38 High duty: PCE value of 30–33 Intermediate duty: PCE value of 28–30 Low duty: PCE value of 19–28 Based on thermal conductivity Refractories may be classified by thermal conductivity as either conducting, nonconducting, or insulating. Examples of conducting refractories are silicon carbide (SiC) and zirconium carbide (ZrC), whereas examples of nonconducting refractories are silica and alumina. Insulating refractories include calcium silicate materials, kaolin, and zirconia. Insulating refractories are used to reduce the rate of heat loss through furnace walls. These refractories have low thermal conductivity due to a high degree of porosity, with a desired porous structure of small, uniform pores evenly distributed throughout the refractory brick in order to minimize thermal conductivity. Insulating refractories can be further classified into four types: Heat-resistant insulating materials with application temperatures ≤ 1100 °C Refractory insulating materials with application temperatures ≤ 1400 °C High refractory insulating materials with application temperatures ≤ 1700 °C Ultra-high refractory insulating materials with application temperatures ≤ 2000 °C Refractory anchorage All refractories require anchorage systems such as wire formed anchors, formed metal (for example, hexmetal) or ceramic tiles to support the refractory linings. The anchorage used for refractories on roofs and vertical walls are more critical as they must remain able to support the weight of refractories even at the elevated temperatures and operating conditions. The commonly used anchorages have circular or rectangular cross-sections. Circular cross-sections are used for low thickness refractory and they support less weight per unit area; whereas the rectangular cross-section is used for high thickness refractory and can support higher weight of refractory