Cupola furnace operation is a transformation process, meaning numerous inputs are transformed into outputs, primarily iron, slag and the stack gases. This cycle is straightforward and somewhat automatic. Feedback loops made through testing and analysis take more effort, but they ultimately help you improve operations (Fig. 1).
The cupola melter is a shaft furnace in which charge materials are fed into the top and continuously melted and discharged at the bottom as long as air is blown into the shaft. Depending on the size of the cupola and volume of air being blown, it can be 30 minutes to an hour before the material charged into the top comes out the bottom. Measurements help give a clear picture of the cupola operations so you can better control the output of the furnace.
While all inputs have an effect on the operations, many cannot be changed by the operator. These include whether the refractory used is acidic or basic, whether the air is cold or hot blast, the type of charging mechanism, charge materials, iron demand, whether it’s lined or unlined, and weather conditions. However, a number of inputs can be changed by the operator day to day and hour to hour and these include the charge makeup, blast volume, blast temperature and use of oxygen (if so equipped).