High temperature cement that is used to line furnaces and stoves in residentail, commercial and industrial applications. Refractory cements can take temperatures up to 3000 degrees and hotter. Examples of use include firebricks for woodstoves and fireplaces, linings for industrial boilers and burners, and crucibles which hold molten metals.
Refractory cement can be purchased already formed, such as with firebricks, or in castable form which can be formed or molded to suit particular needs.
River gravel or crushed fire bricks
Calcium Aluminate cement. (if available in different grades choose the better one)
Lime (lime is usually cheaper, about 80% of the cement price)
You can add into this mix a little standard Fireclay if you like.
Mixture: (parts ratio is 3 x 2 x 2 x 0.5, plus water)
3 shovels of the gravel or crushed firebricks
2 shovels of sand
2 shovels of the cement
half shovel of lime
This amount will require approximately 6-7 liters of water to mix the concrete