INNOVATION March-April 2017

I n the news and on social media, we hear most often from anti-coal groups and infrequently from the coal industry worldwide or here at home in British Columbia. General public perception is that coal is dirty and bad and that we should stop mining it altogether. However, although we have non-coal alternatives for power generation, we currently do not have an economical alternative product to use in the steel- making process. Few people realize that coal is needed to make steel. This type of coal is called metallurgical or coking coal. Coking coal is used for making coke. When coking coal is heated in the absence of oxygen—a process that drives off the volatile components—coke results. This carbonaceous solid is grey or black in color and is comprised of ash and carbon. Another type of metallurgical coal is used in pulverized coal injection (PCI). The coal is powdered, then blown into the bottom of a blast furnace to enhance carbon input in the iron-making process. This type of coal is often cheaper than coke and reduces the costs of making steel. Although alternative technologies to eliminate or reduce use of metallurgical coal in steelmaking are being explored, most remain in the research stage, few have come to the attention of industry professionals, and none have yet been found to be economically viable. At this time, without metallurgical coal, we couldn’t ride bicycles, trains or planes, or drive cars. Steel made without metallurgical coal—or any alternative replacement metal— would be so expensive, only the wealthiest people could afford items made from it. Coal and Steel: The Process In the steelmaking process, coke is fed into a blast furnace, along with iron ore or pellets—typically hematite (Fe 2 O 3 ) or magnetite (Fe 3 O 4 )—and small quantities of fluxes—minerals such as limestone that help to remove impurities from the ore. The blast furnace chemically reduces and physically converts iron oxides into liquid iron that is called “hot metal.”

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M A R CH /A P R I L 2 017

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