About one-third of the UK's smelters are already powered by electricity, but the technology is limited to small- batch processing of up to a maximum five tons a batch. After the metal is poured, the slag has to be removed and then the foundry has to wait for about five hours before the next batch is ready.
Foundries that need a steady stream of molten metal for continuous casting use coke-fired smelters. The incentive to replace coke with electricity comes from the Environmental Protection Act, which will force coke-powered smelter operators to limit emissions.
Barry Taylor, of EA Technology, says that while operators of larger smelters producing more than 20 tons an hour will be able to justify the cost of fitting scrubbers, cleaning up emissions from smaller smelters will put 10 to 20 per cent on the cost of the metal they produce.
Unlike the coke smelter, the electric smelter will be closed, which EA Technology says will minimise emissions, even during charging. Using electricity rather than coke will also reduce the levels of other waste products, such as ash.
One of the main problems the design will have to overcome is how to separate the slag that rises to the top of the molten metal from the molten and solid-metal mixture.
EA Technology has completed the first test runs on its prototype smelter. Six of the UK's electricity companies have put money into the pounds 500,000 project, designed to produce a prototype capable of continuously producing two tons of molten iron an hour. The production unit will have a capacity of up to ten tonnes per hour.
Funding has also come from EA Technology's US counterpart, EPRI (the Electric Power Research Institute).
The leading manufacturer of electric melting furnaces, Inductotherm Europe, has been granted the sole licence.
Although the furnace is being designed to melt ferrous scrap, it will be possible to adapt it for other metals, such as aluminium.