Why is graphite used in crucibles?

Asked by: Claudia Kubota

Graphite has a high melting point (3930°C) and is therefore, used in the manufacture of refractory crucibles for high temperatures. Graphite crucibles are used for melting some metals.

What is the best material for a crucible?

Alumina (Al₂O₃) Crucibles



It is the most commonly used crucible for lab research use. The material has a high melting point is and relatively chemically inert.

Are graphite crucibles good?

Graphite crucibles are high quality melting crucibles. They can be used at temperatures up to 1600C (2900^oF) and are suitable for melting and refining precious metals, base metals, and other products.

What are graphite crucibles?

Graphite Crucibles are refractory containers specially shaped for metallurgical operations. These are made of a mixture of Graphite, Refractory Clay, Grog and other additives. These crucibles are termed as clay bonded Graphite crucibles according to the raw materials used.

Can a graphite crucible melt steel?

My understanding is that even the best made (e.g. Morganite) clay graphite crucibles are rated for about 2900 F. Thus they can be used to melt cast iron, limited number of times. I would not recommend these crucibles for melting steel.

Why is graphite used to make crucible to melt metals Class 10?

Graphite has a high melting point (3930°C) and is therefore, used in the manufacture of refractory crucibles for high temperatures. Graphite crucibles are used for melting some metals.

What is the function of crucible?

A crucible is a cup-shaped piece of laboratory equipment used to contain chemical compounds when heating them to very high temperatures. The receptacle is usually made of porcelain or an inert metal.

Why is it called the Crucible?

Miller intended “The Crucible” as an allegory to McCarthyism. The events that took place during the time the play was written were very similar to the Salem witch hunts. This is why Miller named the book “The Crucible” after the Salem Witch Trials.

How much heat can a graphite crucible take?

5000°F

Graphite Crucible Temperature Range can go as high as 5000°F and can be used in furnaces and high heat processes. Graphite crucibles have many applications within the foundry, laboratory testing, valves, sprinklers, and other heavy-duty products. Graphite crucibles are not very porous.

How is graphite prepared in the crucible?

You can begin by putting the container in the oven at 300 degrees for an hour. Next, temper the crucible by putting it in the furnace. Your flame should be orange and yellow. Slowly heat the container, starting on low power until it’s a red-hot 1110 degrees Fahrenheit.

Do graphite crucibles burn?

The carbon binders and graphite in crucibles would burn when exposed to heat.

What is the melting point of a graphite crucible?

Graphite Crucibles Properties (Theoretical)

Why does a crucible need to be heated?

Heating it on its side is preferred because the overall strain on the ceramic material at the high temperatures used is somewhat less. When transferring a crucible to the dessicator tongs must be used.

Why must the crucible be cold before weighing?

You must let the crucible cool before measuring it because the heat from the crucible warms the surrounding air, which rises, then that air cools down and falls. This rise and fall of surrounding air is called a convection current and will give you an unsteady reading that is rising and falling.

What will happen if you use a crucible that is not completely dry?

Also, if the crucible was not completely cleaned and dried at the beginning of theexperiment that could add more unnecessary mass. All these errors could have been prevented by being more patient. Waiting for thecrucible to heat longer would have ensured there was absolutely no water left in it.

How long do you temper a crucible?

The time taken to pre-heat will depend on the size of the crucible, but is normally in the range 20-40 minutes.

How do you flux a crucible?

Up once you can see a little bit of red coming to the surface yeah a little pinch of flux. And just gently. Put it into the crucible. Like that but the flame onto it.

Can you melt aluminum in a graphite crucible?

Carbon-bonded and ceramic-bonded clay graphite and silicon carbide crucibles are widely use in melting and holding aluminum and aluminum alloys, aluminum-bronze, copper and copper-based alloys, cupro-nickel and nickel-bronze alloys, precious metals, zinc and zinc oxide.

Can you use the same crucible for different metals?

It is better to use different crucibles for different types of metals to avoid contamination. Also make sure to completely empty the crucible after each use as the metal left to solidify may expand on re-heating, which may destroy the crucible. The crucibles should be “tempered” before usage.

Can stainless steel be used as a crucible?

Stainless steel crucibles can be used in cryo applications. They are a formed from a single piece of material and are less fragile than porcelain crucibles when dropped on a hard surface.

Can you melt copper in a steel crucible?

Crucibles are made of steel, silicon carbide, and often clay graphite. They resist high temperatures and will hold and heat the copper you are melting. Keep in mind that you will also need proper tongs to grasp the crucible if you intend to pour your liquid copper solution into any molds.

Can cast iron be used as a crucible?

What it looks like. And give you a quick look inside it and this crucible has 25 melts in it with cast iron.

What is a steel crucible made of?

Crucible steel is steel made by melting pig iron (cast iron), iron, and sometimes steel, often along with sand, glass, ashes, and other fluxes, in a crucible. In ancient times steel and iron were impossible to melt using charcoal or coal fires, which could not produce temperatures high enough.

What can I use as a crucible for aluminum?

So I'm going to show you you know a couple different types what I see a lot is people using the stainless steel cups. You could pick them up the thrift store pretty cheap.