Question

Graphite is used for making electrodes and articles like writing pencils. It is made by heating coke with some silica for many hours in?
(A) A blast furnace
(B) A high electric furnace
(C) The presence of air
(D) A blast of steam under pressure

Answer 1

There is a process named Acheson process which was invented by Edward Goodrich Acheson to synthesize silicon carbide (SiC) and graphite.

Complete step by step answer:
- Graphite is an allotrope of carbon which occurs naturally. It is a native mineral found in metamorphic and igneous rocks.
- Graphite is very soft and gets cleaved with very light pressure and has a very low value of specific gravity.
- Graphite is relatively easy to make when compared to diamond or buckminsterfullerene) because it is the most chemically stable form of carbon.
- In the Acheson process, pure silica sand and coke are reacted in an electric furnace at temperatures ranging from ${2200^ \circ }C - {2480^ \circ }C$ .
- SiC ceramics have high temperature load bearing strength and dimensional stability. They exhibit a great thermal shock resistance property because of their high conductivity of heat.
- When it is heated, the silicon is removed and graphite is left behind. After discovering this process, Acheson developed an efficient high electric furnace based on resistive heating, which is the basis of most of the silicon carbide manufacturing today.
- Electric furnace is nothing but a cheating chamber with electricity as the heat source for achieving very high temperatures to melt and alloy metals and refractories.
- Hence, Graphite is used for making electrodes and articles like writing pencils. It is made by heating coke with some silica for many hours in a high electric furnace.
So, the correct answer is “Option B”.

Note: Silicon carbide is a very useful material used in applications requiring high endurance, such as car brakes, car clutches and ceramic plates in bulletproof vests.