Typical DC arc furnace.

DC Furnaces

Bateman Mineral Recovery makes use of Mintek’s patented DC arc furnace technology to remelt and refine ulltrafine baghouse dusts and other ultrafine wastes from the ferroalloy industry (which otherwise present environmental and health threats) into valuable ferroalloys. We are using this technology at Mogale Alloys where a 40 MVA DC furnace produces a Fe, Ni, Cr alloy from stainless steel EAF dust and chromite fines

Furnace Operation

A continuous direct current is supplied by a transformer and rectifier. The central graphite electrode forms the cathode (-) and the hearth the anode (+). The anode and metal bath are kept at earth potential, while an arc is struck between the cathode and the slag bath.

Convection between the arc, a high-velocity jet of plasma (ionised gases and electrons), and the bath results in most of the energy transfer to the bath. The balance of the energy transfer is achieved by resistive heating from the current flowing through the bath.

There are two options for material feeding:

  • through a hollow electrode – to introduce the feed into the hottest zone, thereby maximising reaction rates.

  • through feed ports in the roof – allowing the use of a solid electrode which is simpler and more cost-effective to operate.