New electric furnace that converts low-grade scrap into ferrous raw materials (1990s, NKK)

New electric furnace that converts low-grade scrap into ferrous raw materials (1990s, NKK)
In the 1990s, the Japanese steel industry faced an urgent need to establish a manufacturing process based on resource recycling in the face of tightening international environmental regulations and the development of domestic recycling policies, while facing economic stagnation after the collapse of the bubble economy. The problem at the time was the handling of low-grade scrap with iron content of only around 40%. Construction demolition scrap and home appliance scrap contained many impurities, and the presence of copper, tin, and other impurities adversely affected the quality of steel products.
The new electric furnace technology developed by NKK combines scrap preheating, oxygen-enriched combustion, and advanced refining control, making it possible to efficiently melt low-grade scrap and recycle it as ferrous raw materials. The preheating method using heat from exhaust gas improves energy-saving performance, and the improved refining process, which suppresses the effects of impurities, enables stable processing of miscellaneous scrap, which was difficult to achieve in the past.
This technology not only contributed to an increase in the steel recycling rate and waste reduction, but also attracted attention as an upgrade-type recycling technology that converts scrap not merely into a low-value resource but back into a raw material for high-value-added materials. It symbolized the structural shift in the steel industry from mass production to resource recycling, and became an important technological foundation for the Japanese steel industry to achieve both environmental responsiveness and production efficiency.