By Nathan Weis
The blast furnace is a furnace created for the sole purpose of smelting metals (usually iron) so that they can be purified and forged into tools for various uses. The oldest recorded blast furnaces were found in China, dating back to the first century AD. Ever since their invention, blast furnaces have allowed the industrial-scale metal production required for the growth of societies. They greatly increased the demand for metal ores, creating a boom in resource exploitation of metal-rich mining areas. Additionally, the magnitude of tools produced from blast furnace smelting gave people (especially farmers) an increasing ability to modify the lands around them. This was accomplished by creating plows, axes, scythes, and other such tools with the metal produced from a furnace. However, blast furnaces were fueled by either charcoal or coke (a byproduct of coal) resulting in large amounts of CO2 and slag pollution. Blast furnaces are still in use today, albeit with major upgrades in order to increase performance and decrease pollution. Modern iron and steel products now go through other refining processes, but blast furnaces are still the crucial step in getting metals from ore. In the 21st century, blast furnaces are significant part of the Anthropocene because they allow for: the large-scale creation of landscape-altering tools, a demand for resource exploitation of metal ores, and a large contributor of world air pollution. They define the Anthropocene as a species-thinking, polycentric era by allowing many nations to become “centers” of metal production.
The blast furnace refines the iron and steel required for metal tools used today. In the 21st century, “approximately 70% of the global steel production involves the use of BF”, we can see that the blast furnace shows a polycentric view of the Anthropocene. Its earliest forms were created in China, it saw first European use in the middle ages, and after the 18th century industrial revolution, it could be found around the world. Since every modern nation that refines iron and steel uses blast furnaces, instead of just Europe, they all can be seen as ‘centers’ of contribution to the human impact of the Anthropocene, which is defined as polycentrism. This leads into a defined ‘species thinking’ narrative of the Anthropocene, where humanity as a whole is responsible for the changes humans have caused. To be specific, “agricultural land covers 38.4% of the world’s land area as of 2011,” and the tools required to create this farmland were all made from steel and iron refined in blast furnaces. So it is not the blast furnace itself that causes the landscape to alter, but it allows the mass production of tools that can, and it can be found across the globe. While landscape alteration is an indirect result of blast furnace usage, resource exploitation feeds directly into the impact the blast furnaces have on the Anthropocene.
The resource consumption required for the creation of iron and steel from blast furnaces is great, and it continues to increase as demand for metals goes up. The mining of iron ore is not a very environmental process, as around 2 billion metric tons are mined each year from the Earth’s crust. One of the main impacts from mining iron is clearing large amounts of vegetation, which causes ecosystem disruption. Another is the disposal of the slag which forms an alkaline mud which can seep into underground reservoirs when it’s not disposed of properly. Also, iron ore mining severely affects the water retention capability of the soil, and can lead to rapid erosion within the mined areas. In addition to the iron ore, coal must also be mined in order to fuel the chemical reactions that heat the furnace and refine the iron. From the resource consumption standpoint, the blast furnace shows one of Bonnueil’s narratives of the Anthropocene: “Eco-Catastrophism”. This narrative describes the Anthropocene as a series of environmental changes leading to a tipping point that would cause an irreversible decline due to destruction of habitable ecosystems. This would be caused by over mining and pollution due to production of steel and iron from the blast furnace. On this note, the majority of pollution that comes from a blast furnace is toxic gases. The blast furnace could significantly contribute to carbon dioxide emissions which lead to the warming of the Earth’s atmosphere, which would destroy ecosystems and fit into this narrative.
The blast furnace can have significant amounts of hazardous byproducts, almost all of which are released into the air as toxic gasses. These gasses are harmful to almost all living things, and there are many findings concluding that enough waste has been released to affect the entire atmosphere as a whole. One of the largest concerns for pollution in steelmaking is CO2 gas, as it is the largest (by volume) pollutant from the steelmaking process. “On average, 1.8 tonnes of CO2 are emitted for every tonne of steel produced, and the iron and steel industry accounts for approximately 6.7% of total world CO2 emissions”. This means for every ton of steel, almost 2 tons of CO2 gas is released. Additionally, while steelmaking does not occupy a majority percentage among CO2 polluters, it is still a significant amount. According to the EPA’s latest Greenhouse Gas Inventory Report, total CO2 emissions for 2013 were at just over 5,000 million metric tons, meaning that steelmaking as a whole accounts for about 335 million metric tons of CO2 pollution per year. As concern for climate change and other hazardous results from all of this waste rises, industries responsible for a significant amount of the pollution (mostly via blast furnaces) have begun looking for cleaner ways to produce steel. This has led to the rise of “green steelmaking,” or newer, less polluting processes for creating steel. By making significant efforts to change the blast furnace, or replace it altogether, in order to lower pollution and create a safer environment by using new technology, carbon emissions can be greatly reduced.
Bonnueil’s “Post-Nature” narrative has become apparent from blast furnaces very recently, as long-term environmental costs have become apparent, and many industries have taken it upon themselves to try and make new, clean, and cost effective steelmaking processes. One such process was discovered by researchers at MIT in 2013, which they utilize “molten oxide electrolysis,” and is “an electrometallurgical technique that enables the direct production of metal in the liquid state from oxide feedstock”. This process uses electrolysis in the molten iron oxide to remove oxygen from the metal, so it bonds as oxygen (instead of carbon dioxide) and exits the furnace. Because the oxygen in the metal is very reactive, they have made a thin lining composed of an iron-chromium alloy which resists bonding with oxygen, but can still conduct electricity. While this process looks promising, cost-effectiveness is up for debate, and the high temperature of the reaction (around 1550 degrees Celcius) may pose long term issues. There are other attempts at green steelmaking, such as reduction of iron with other elements (like hydrogen), the capturing of carbon dioxide gas within the furnace, and the reforming and/or use of other materials (instead of coke) like charcoal, to list a few. As the largest industrial source of pollution, the steel and iron making industry has been working on many different ways to produce less carbon dioxide waste from the steelmaking processes. Many have tried removing the reaction that creates carbon dioxide altogether from the steelmaking process, while others have simply tried using cleaner materials, or even finding ways to “hold in” harmful carbon dioxide gases within the furnace. Due to these efforts, carbon dioxide emissions have slightly decreased in recent years, and with enough effort and luck, they will hopefully continue to decline in the future.
The blast furnace creates an essential process to produce necessary metals that are needed to operate a modern world. Large buildings, stainless steel appliances and tools, car parts, electronics, and many other common items would be non-existent without modern blast furnaces.
In the 21st century, blast furnaces are significant part of the Anthropocene because they allow for: the large-scale creation of landscape-altering tools, a demand for resource exploitation of metal ores, and a large contributor of world air pollution, which all define the Anthropocene as a species-thinking, polycentric era, following Bonnueil’s narrative of “Eco-Catastrophism,” but with new efforts leading to a “Post-Nature” narrative.
Allanore, Sadoway, & Yin. “A new anode material for oxygen evolution in molten oxide electrolysis.” Nature Volume 497, Issue 7449, Letters. 353–356. May 16, 2013.
FAOSTAT. “FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS STATISTICS DIVISION.” FAOSTAT Database. March 2016. http://faostat3.fao.org/home/E
Institute for Industrial Productivity. “Blast Furnace System.” Industrial Efficiency Technology Database. 2013. http://ietd.iipnetwork.org/content/blast-furnace-system
Kou, Sindou. “Course Notes Chapter 1: Slag Chemistry and Metal Extraction Process.” MS&E 332 MACROPROCESSING OF MATERIALS. 2015.
Tuck, Christopher A. “IRON ORE.” U.S. Geological Survey, Mineral Commodity Summaries. 84-85. January 2015.
U.S. Environmental Protection Agency. “Inventory of U.S. Greenhouse Gas
Emissions and Sinks.” April 15, 2015.