Analysis of steel production in Thailand: Environmental impacts and solutions

Steels were the upstream of various products. The environmental performance of steel can affect those of the downstream products. In this work, environmental impacts of individual steels, i.e. slab, hot-rolled, cold-rolled, hot-dipped galvanized, and electro-galvanized steels, were studied, via life cycle assessment. The impact assessment methods of IPCC 2007 GWP 100a and Eco-indicator 99 (H) were used to cover the impact categories of Global warming potential, Fossil fuels, Ecotoxicity, Minerals, Carcinogens, and Respiratory inorganics. In all categories, the slab showed the lowest impacts and the hot-dipped galvanized steel showed the highest impacts. The main causes of the impacts were attributed to these inputs; steel, energy, and zinc. The emissions from steel production plants showed relatively low impacts. Small amount of zinc input can cause huge environmental impacts. The impacts of Fossil fuels, Minerals, and Ecotoxicity, of 1-kg zinc were 2.9, 116.9, and 39.6 times of those caused by 1-kg cold-rolled steel, respectively. The reduction of zinc consumption and the improvement of zinc production process, in terms of reduction of heavy metal emissions, could largely improve environmental performance of the galvanized steels.