Industrial copper smelting

Roast concentrate is heated in a reverberatory furnace. It is a long hearth furnace, covered with a roof and heated by combustion of oil or powdered coal.

The furnace is charged with hot pre roasted calcine or with wet flotation concentrate. Silica is added to flux  and to give a suitable slag.  In some plants line or limestone is also added. The molten matte is tapped from tap holes along the middle of the furnace, whereas slag is tapped from the flue gas end of the furnace.

The temperature is kept about . Hot gases carry sufficient amount of heat and are usually passed through a steam boiler before then go to gas cleaning and discharge.

Copper content of slag is about

In flash smelting finely ground ore, together with flux is introduced through a suitable burner. The matte and slag sink whereas the furnace gases are removed through the off take. In flash smelting preheated air or pure oxygen is used to produce required amount of heat.

In most cases sufficient heat is generated by oxidation of FeS. Low grade concentrate contains more FeS Flash smelting combines both roasting and smelting.

Exercise in matte smelting

a) In a copper ore chalcopyrite is and . Determine the% of copper, iron and sulphur

b) What would be the% gangue in a chalcocite ore if the copper content is same as in 1a)? The ore contains .

c) What would be the entire% composition of matte containing 38% copper when the matte is expressed by the formula ?