If you want to heat solids with a flame, you need to use a crucible. When using the crucible cover, the crucible is usually tilted on the crucible to prevent it from being washed away by hot air and allow air to flow in and out freely, so that oxidation reaction may occur. Because the bottom of the crucible is small, it usually needs to be heated directly on the mud triangle with fire. On the iron tripod, the crucible can be placed as required or as required by the experiment. When heating, the crucible cannot be placed on the cold metal table immediately to avoid cracking due to violent cooling. Wooden tabletop cannot be placed immediately to avoid damaging the tabletop or causing fire. The proper way is to put it on the iron tripod for natural cooling, or put it on the asbestos net for slow cooling. Use a crucible clamp when using a crucible.

Corundum crucibles are required to heat solids at high temperatures. When using the crucible, the crucible cover is usually placed on the crucible to prevent the heated object from jumping out and allow the air to flow freely, so as to produce oxidation reaction. Because the bottom of the crucible is very small, it should usually be placed on a triangle and heated directly with fire. The crucible can be placed vertically or obliquely on the iron triangle support, and can be placed according to the needs of the experiment. In order to avoid cracking due to rapid cooling, the heated crucible should be placed on the cold metal table immediately. Wooden tabletop cannot be placed immediately to avoid damaging the tabletop or causing fire. The proper way is to put it on the iron tripod for natural cooling, or put it on the asbestos net for slow cooling. Use a crucible clamp when using a crucible.

Corundum is basically pure alumina. Artificial corundum is pure alumina fired at high temperature. It has high temperature resistance, melting point of 2045 ℃, high hardness and good acid and alkali resistance.

Corundum crucible can be used for melting and sintering of some alkaline fluxes, but the temperature should not be too high and the time should be as short as possible. Sometimes it can replace nickel and platinum crucibles, but it shall not be used when measuring aluminum and aluminum interfere with the measurement.