The manufacture of coke at Hwange

• Coke is a hard prous residue formed when coking coal is heated to 1250°C in the absence of air
• It is almost pure carbon
• It is often used as a raw material by the metal industry

The process of making coke

• Coaking coal is fed into a battery of long coke ovens
• The ovens are lined with silica brick
• The ovens are heated with coal gas
• After 16 hours the coal is transformed
• If 17 tonnes are fed into the ovens about 12 tonnes of coke are obtained
• After the process is complete the red-hot coke is ejected from the ovens and drenched with water
• When the coke is drained it is send to ZISCO and other metal extracting companies
• Coking byproducts make up the difference between the mass of the coal input and the coal output

The by-products and their uses

• Various by-products are given off by the coking process
• Some of them are used as they are for example coal gas but some have to be refined
• After they are refined these by-products have different uses
• The table below shows the various by-products of the coking process and their uses

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