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Preamble
Technique of smelting and converting as applied for copper production is not applicable for production of  from sulphide ore since does not melt even at . Concentrate is sinter roasted, that means sintering and roasting of sulphide concentrate occur simultaneously.
The burden Zinc sinter and coke is preheated to about  before it is charged into Imperial Smelting Furnace (here after ISF), which is very similar to the blast furnace. Preheated air is introduced at the tuyeres that reacts with coke to give  and generates a temperature of about . Rising within the shaft reacts with  to produce a gas mixture of about  and  and .
The hot gas mixture is shock cooled in a lead bath to about . Zinc condenses and dissolves in lead without reoxidation.
Materials and heat in balance imperial smelting process
In an imperial smelting blast furnace the sinter consists of  and
The coke is regarded pure amorphous carbon. All is reduced to Zn vapor and  to liquid lead, whereas  and  form a molten slag. The gas composition after reduction is 7%Zn with  ratio 0.5
- Make a mass balance and calculate wt. of carbon and volume of air and volume composition of top gas.
- Make an overall heat balance when the raw materials are introduced at 1100K, liquid products are withdrawn at 1600K, and the top gas temperature is 1300K.
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