The invention relates to a method of preparing a mineral melt in a cupola furnace that uses at least one plasma torch to provide heat energy to the furnace. The plasma torch uses nitrogen, carbon monoxide, carbon dioxide, or a mixture thereof as the carrier gas. The invention also relates to a cupola furnace for the preparation of the mineral melt, and the use of a plasma torch in a cupola furnace to reduce the amount of NO.sub.x and/or hydrogen in the furnace off-gas.

The invention relates to a method of preparing a mineral melt in a cupola furnace that uses at least one plasma torch to provide heat energy to the furnace. The plasma torch uses nitrogen, carbon monoxide, carbon dioxide, or a mixture thereof as the carrier gas. The invention also relates to a cupola furnace for the preparation of the mineral melt, and the use of a plasma torch in a cupola furnace to reduce the amount of NO.sub.x and/or hydrogen in the furnace off-gas.