Technology of roasting

Roasting may be carried out in different furnaces. Multiple hearth furnace was dominant for a long time for roasting of sulphide ores. Now flash roasting is developed. Fluidized bed roasting is also being in use. A problem on fluidized bed roasting is discussed is lecture 17.

Roasting is strongly exothermic process. The calculation of adiabatic temperature is important and will be discussed in lecture 17.  

A copper concentrate may be roasted autogenously in a multiple hearth furnace provided sulphur is not eliminated completely. Dead roasting would require additional thermal energy. Heat balance calculations will be taken in subsequent lectures. Material balance will also be illustrated first because heat balance cannot be done without materials balance. In subsequent lectures attempt has been made to illustrate materials and heat balance.

Conclusions:

In this lecture thermodynamics of roasting is briefly presented to impart a feel about the formation of different phases during roasting of sulphide ore. In this connection predominance area diagram is a very useful one to obtain the conditions for the formation of a phase.


Reference:

Resenquist : principles of extractive metallurgy

Ray, H S; Sridhar, R and Abraham, K.P:  Extraction of non ferrous metals