Provided is an injection refractory material capable of improving sealability of a gap in a kiln or furnace. Specifically, in an injection refractory material applicable to a kiln or furnace, a composition thereof is adjusted such that, when the injection refractory material is heated in an environment having an ambient temperature of 80 to 500°C, it undergoes a volume expansion of 1.3 times or more its initial volume before the heating. For example, the injection refractory material contains: thermoplastic plastic bodies each encapsulating liquefied gas, in an amount of 0.5 to 3 mass%; and silicate in an amount of 3 to 10 mass%, with respect to a total amount, 100 mass%, of the injection refractory material.

A method of manufacturing large thin wall ceramics board includes pulverizing and uniformly mixing, in dry content conversion, plasticity clay in an amount of 30-40% by weight, wollastonite having an aspect ratio of more than 10 in an amount of 20-50% by weight, and feldspar and talc in an amount of 10 50 % by weight to form a mixture. The mixture is added with a solution having a 16-21% weight of the weight of this mixture. The solution has 10% by weight of a paraffin emulsion. The clay-like composition is extruded with a vacuum kneading machine to form a cylindrical shape. The extruded clay-like composition is made into dough board compact of desired thickness after being partially cut parallel to the cylinder. The dough board compact is heated to approximately 80 degrees Celsius with far infrared radiation. The heated dough board is transported on a heat proof metal mesh belt having temperature of between 80 and 150 degrees Celsius, and then gradually heated and dried at 150 to 350 degrees Celsius to dehydrate the dough board. The dehydrated bough board is baked at 1000-1200 degrees Celsius in roller hearth kiln combustion heating device.