High Pure Graphite Crucible for Melting Gold

1. Graphite crucible cannot be exposed in moisture, and must be placed in indoor dry place or wooden shelf. Maintain ventilated. Moisture is strictly prohibited. Damped crucible is likely to crack.

2. Each crucible, especially damped ones, must be preheated and roasted in drying equipment or next to a ground furnace before use. The roasting temperature should start from a low temperature of 100°C below. Roast it to 150°C at a speed of not higher than 30°C per hour. Preserve the heat for about 8 hours and then dry it. The crucible dried next to a ground furnace should be placed at least for one shift, and often turned to change direction, till workers feel the internal wall of crucible is hot.

3. The melting time for the first time should be at least twice of the normal melting time, in order to avoid cracking inside the crucible due to heating up too fast, or even cracking immediately when the fire sets on.

4. Handle with care. Falling or shaking is strictly forbidden in order to present cracking. Crucible should be placed below the mouth of furnace to prevent the furnace lid abrading the upper edge of the crucible and thus affecting the capacity.

5. Pour out the remaining cold metals inside the crucible after use, and then add new materials. Carefully and gently add new materials into the crucible. Feed materials according to the capacity of crucible. It is not allowed to feed too many materials, in order to prevent crucible from swelling or bursting.

6. Knock gently to remove slags and cokes on the internal and external wall of the crucible. Avoid damaging the crucible body.

7. In the melting process, do not add chloride solvents in order not to corrode the crucible. For the furnace that uses oil and coal gas as fuels, the oil wind should not reach one part of the crucible directly. Turn around the crucible from time to time, in order to avoid local damage.

8. Clamps and other discharging tools should comply with the shape of the crucible. During furnace discharging, remove the cokes on the external wall of the crucible, and lower the furnace temperature; do not discharge at high temperature after stopping blasting. Clamp the upper and middle parts instead of the top of the crucible in order not to damage the crucible. Graphite crucible is used mainly to melt gold, silver and other precious metals.