Typical cupola slag composition

Cupola slag consists of 30 % refractory material, 10 % sand (from internal scrap), 40 % CaO (flux), 10 % cokes ashes, and 10 % bum-off material. 

An important aspect of cupola slag is its high Si02-content. After quenching, the slag has a vitrified stmcture. This generates an inert non-leaching material. 

The cupola furnace has the specific feature that the lining material (quartz-clay mixture) of the furnace at the melting zone only lasts for one melting campaign. The main part of the refractory is converted into slag. The amount to be taken out and disposed of as waste is much smaller than the applied amount. 

500 - 600 kWh of electricity is used to melt and raise one tonne of steel to its casting temperature. Furnaces are normally rated at 500 kVA per tonne, giving a melting time of about 1.5 hours. 

In terms of the chemical composition of the particulate matter, an even bigger range of measured data can be observed. Table 3.9 gives an overview of the reported figures in the literature. 

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Table 3.8 Typical cupola slag composition [172, Neumann, 1994], [156, Godinot, 2001]...

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