Acheson process

[2] In the furnace, the silicon dioxide, which sometimes also contains other additives along with ferric oxide and saw dust is melted surrounding a graphite rod, which serves as a core.

[1] The result of the carbothermic reaction is a layer of silicon carbide (especially in its alpha and beta phases)[1] forming around the rod and emission of carbon monoxide (CO).

[5] After discovering this process, Acheson developed an efficient electric furnace based on resistive heating, the design of which is the basis of most silicon carbide manufacturing today.

[3] To manufacture synthetic graphite items, carbon powder and silica are mixed with a binder, such as tar, and baked after being pressed into shape such as that of electrodes or crucibles.

[12] Silicon carbide was a useful material in jewelry making due to its abrasive properties, and this was the first commercial application of the Acheson process.

Cross-section of an Acheson furnace for producing bulk silicon carbide or graphite
Diagram of a resistive Acheson furnace for producing electrode rods formed from powdered coke mixed with silica clay:
a – mixture of coke and sand,
b – bricks,
c – carbon electrodes,
d – refractory material,
e – rods to graphitize,
f – granulated coke
Diagram of related Castner lengthwise graphization furnace, legend is same as for the Acheson furnace