| |
Below is the result.
Heat input |
Cal |
Heat output |
Cal |
Heat of reaction |
58196 |
Heat Absorbed by decomposition
of CuFeS2 |
8526 |
|
|
Matte |
8201 |
|
|
Slag |
16616 |
|
|
Gases |
31964 |
|
|
Subtotal |
65307 |
|
|
Heat loss as10% of output |
6530 |
|
|
Total heat output |
77831 |
|
b)Calculation to provide heat deficit
i) Preheating of air
Preheating of air aids sensible heat. Air preheat temperature is important, this temperature can be calculated by equating heat loss equal to heat input by airif mean heat capacity of air is 
Temperature of preheat air 
ii) By burning natural gas
Each mole of methane produces  of heat on combustion. Out of which some amount of heat will be carried away by the products of combustion of methane at the furnace temperature and is assumed to be 1500K. The products of combustion are  when methane is burnt with stoichimetric amount of air.
We have to recalculate composition of exit gas. The revised composition of the gas is %
iii) By enriching air with oxygen. Oxygen enrichment of air decreases nitrogen and hence heat carried away by the flue gas will also decrease. What amount of oxygen must beadded to meet the heat deficit?
Answer 85 m3/ton concentrate
Revised composition of flue gas 
References
- Ray, H.S; Sridhar, R and Abraham, K.P: Extraction of non ferrous metals.
- Rosenquist : Principles of extractive metallurgy
- Butts, Allison: Metallurgical Problems, McGraw Hill Book Company, 1943
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