Operation of a cupola
Cupola is used to melt pig iron to make iron castings in foundry. Charge consists of pig iron, scrap and limestone and coke.The oxidation of the following elements takes place:
 are slagged. Loss of carbon from pig iron may occur due to oxidation of carbon. However, this loss of carbon is compensated by absorption of carbon from coke. Cupola runs intermittently.
Air is blown through the tuyeres.
In material balance, the input consists of pig iron, scrap, limestone, coke and air. Whereas output consists of cast iron, slag and exit gases  etc.
In cupola melting the calculation on material balance is required to determine the amounts of various inputs and outputs such that material management can be done for smooth inflow and output of materials.
Change balance calculations
A cupola melts per hour 15 taons of pig iron of composition C 3.5%, Si 2.2% Mn 0.8% PO.7% and rest Fe; and 5 tons of scrap containing C 3,%, Si.8%MN 1.1% and PO.2%.
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The dry air used is  measured at  to melt 1ton of pig iron and scrap per minute.
During melting  of total  charged,  of total  charged  of total  charged and  of C is oxidized, of carbon of coke is absorbed by iron during melting. Enough  is charged to give  in slag. The coke is  and weight of coke is  of the total weight of pig iron and scrap.
Required:
a) Charge balances of cupola for 5 hr run.
b) The % composition of resulting cast iron, slag and gases.
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