Dioxin Reduction Measures of the Japan Iron and Steel Federation - Technological Challenges and Environmental Regulations in the Late 1990s

Dioxin Reduction Measures of the Japan Iron and Steel Federation - Technological Challenges and Environmental Regulations in the Late 1990s

In the late 1990s, the Japanese steel industry was faced with the inevitable challenge of "environmental compliance. Particular attention was paid to dioxin generated in electric arc furnace steelmaking. The dioxin emissions from steel scrap often contained plastic-coated wires and vinyl chloride fragments, which, when burned at high temperatures, produced dust containing chlorine compounds that caused dioxin to be generated. The steel industry needed to embark on full-scale countermeasures.

The Japan Iron and Steel Federation (JISF) established a three-year research committee, bringing together more than 50 companies to develop technologies for reducing dioxin emissions, starting in FY1997. There were three main pillars of related technologies.

The first was "raw material countermeasures. Optical sorters and magnetic and specific gravity separators were introduced to remove vinyl chloride and other chlorine-containing substances from scrap in advance. This was done to reduce the amount of chlorine brought into the furnace.

Second, "optimization of combustion and operating conditions. By improving the temperature control in the electric furnace to a high degree of precision and promoting complete combustion, operating techniques were studied to avoid the temperature range (200-400°C) where dioxin is likely to be generated as much as possible. Furthermore, oxygen-enriched operation and quenching techniques were introduced to reduce the formation of dioxin.

Third is "exhaust gas treatment technology. The exhaust gas from the furnace was treated through dust collection using bag filters and quenching equipment. In particular, the rapid cooling system (rapid cooling system) was effective in quickly passing through the temperature range where dioxin is resynthesized, a technology that was attracting attention in Europe. In parallel, an attempt was made to capture residual dioxin in the exhaust gas by activated carbon adsorption.

These technologies were not merely in response to environmental regulations, but were also designed to improve the soundness of steel recycling and to comply with international environmental standards. At the time, the EU was moving toward lowering the dioxin emission standard for waste incinerators to 0.1ng-TEQ/Nm³, and Japan was under pressure to take measures with the same level in mind.

These efforts led to the acquisition of ISO14001 certification and the publication of an environmental report as part of CSR activities, and marked the beginning of the redefinition of the steel industry as an industry that coexists with the environment. It was also a turning point in an era that redefined environmental impact reduction as "industrial competitiveness" through technological innovation.