Can we say that refractory is a metal?
You can not say that refractory is a metal. A refractory material is one that retains its strength at high temperatures. ASTM C71 defines refractories as “non-metallic materials having those chemical and physical properties that made them applicable for structures, or as components of systems, that are exposed to environments above 1000 °F (800K, 500 °C)” A metal is a chemical element whose atoms readily lose electrons to form positive ions (cations), and form metallic bonds between other metal atoms and ionic bonds between nonmetal atoms. http://en.wikipedia.
