Introduction of Crucible
A crucible is a cup-shaped vessel used in the laboratory to heat solids at high temperatures.
There are many types and specifications of crucible, and the crucible is not limited by production scale, batch size and the variety of melting substance in the application, so it can be selected arbitrarily, with strong applicability and can ensure the purity of the melting substance.
1. Place it in a dry place after use, and avoid rain intrusion by all means;
Bake slowly to 500 degrees Celsius before use.
2, should be according to the capacity of the crucible feeding, avoid crowded too tight, in order to avoid the metal thermal expansion of the crack crucible.
3, take out the metal melt, it is best to spoon out, as little as possible with calipers, if calipers and other tools should be consistent with the shape of the crucible, to avoid local force is too large and shorten the service life.
4, crucible service life is related to usage, should avoid strong oxidation flame directly sprayed to the crucible, and make the crucible raw material oxidation short life.
The production materials of crucible can be summarized into three types. One is crystalline natural graphite, two is plastic refractory clay, three is calcined hard kaolin skeleton clinker. Since 2008, began to use high temperature resistant synthetic materials, such as: silicon carbide, alumina, emery and ferrosilicon as crucible skeleton clinker. This clinker has a significant effect on improving the quality of crucible, enhancing the density and mechanical strength of crucible.
Crucible can be divided into graphite crucible, clay crucible and metal crucible.
In the graphite crucible, there are general graphite crucible, special-shaped graphite crucible, high purity graphite crucible three kinds.
Various types of graphite crucible are different in terms of raw materials, production methods, technology and product models and specifications due to their different properties, uses and conditions.
There are three kinds of crucible: the first kind is copper crucible; The second type is copper alloy crucible, special circular with 100 numbers, circular with 100 numbers, the third type of steel crucible, with 100 numbers.
Crucible size, usually denoted by serial size, no. 1 has a capacity to melt 1000g brass and weighs 180g.
The melting amount of a crucible in melting different metals or alloys can be calculated by multiplying the bulk density specification number of the crucible by the corresponding metal and alloy coefficient.
The production materials of crucible can be summarized into three types.
One is crystalline natural graphite, the other is plastic refractory.
Nickel crucible is suitable for melting samples with NaOH, Na2O2, Na2CO3, NaHCO3 and alkaline solvents containing KNO3, but not for melting samples with acidic solvents such as KHSO4 or NaHSO4, K2S2O7 or Na2S2O7 and basic sulfide flux containing sulfur.