Introduction:
Iron (symbol Fe and atomic number 26) is a popular metal, which is used in a variety of applications. As it is abundantly available in the earth, it has been used in different forms since time immemorial. Today, iron ore extraction is a well defined and regulated process. However, there are many environmental and health hazards related to the metal and extraction. A critical analysis of the exact impacts can help in achieving an overall sustainable productivity from the element. With that end in mind, this paper deals with the characteristics of Iron; places where it is available; how it is extracted, and the cost involved; its environmental and health impacts; and finally, steps that can be taken to use it more efficiently.
Iron is a lustrous, malleable, and ductile metal which exists in four different crystalline forms. It exhibits multiple oxidation states, which make it a very active element. It can thus corrode easily, and due to its high reactivity with water, form rust in the presence of moist/damp air. It is abundant in Canada, India, USA, Sweden, and Venezuela.
Extraction process and Cost:
Iron ore is first crushed using heavy crushers, which breaks it into smaller pieces. This lump of ore is then heated in order to decompose carbonates into oxides, in the absence of air. The resulting ferrous (2) oxide is converted to ferric (3) oxide. This is followed by the process of ‘smelting’ the concentrated ore in a Blast Furnace, from which Iron metal is collected. The process illustrated requires heavy machinery, and a huge furnace with a proper control system. These require a large capital, and reasonable operating costs. However, since the productivity of the element is high, the process is generally highly profitable. Further, distribution of the processed element is quite simple, and the overall cost of processing is remarkably inexpensive. However, it is the maintenance cost associate with iron products that is undesirable. The main reason for this is the high reactivity of the metal, which leads to quick corrosion (Jose, 2002). Therefore, lubricants and other protective layers are required to ensure durability of the product. Figure 1 is a photo of an iron ore yet to be processed. Figure 2 is a detailed block diagram of the iron ore extraction process.
Figure 1: Iron Ore
Figure 2: Iron Ore Extraction
Iron is one of the most commonly used metals. Its high strength and low cost make it an irresistible choice in many industry applications (Schmitz Jr, 2005). From high end electronics, to cars to screw drivers to paper staples, some form of iron is used in almost every product one comes across. In most of the applications, steel the most widely used alloy of iron may feature. Due to its unbeatable properties at a low cost, there is no efficient substitute for iron and its alloys as of today.
Health Impacts:
Iron is an essential nutrient required for proper metabolism of living beings. It is commonly found in many food products, including meat, potatoes, and other vegetables. It is commonly associated with good eyesight, general stamina, and immunity. However, presence of excessive iron in the body results in damage of cells. Chronic inhalation of the metal can result in siderosis, lung cancer and other respiratory ailments (Boyd, 1970). According to the Dietary Reference Intake or DRI, the tolerable upper intake of Iron is 45mg a day and 40 mg a day for an adult and a child respectively.
Environmental Impacts:
Iron (III)-O-arsenite, pentahydrate is known to be an environmental hazard. If this chemical comes in contact with air, water or plants, there can be extensive damage due to its toxicity. Further, this chemical is known to persist in the environment, causing toxic pollution. Well regulated use of Iron, can make it a big boon to mankind. Some iron extraction/manufacturing industries still do not adhere strictly to the policies which result in environmental degradation. Extensive mining and extraction in the recent past has given rise to many local water bodies being poisoned. Figure 3 shows an affected area due to excessive mining of iron.
Figure 3: Area affected due to excessive mining
Environmental committees all over the world are looking to put an end to this, by careful monitoring. Extensive research groups have been sponsored by governments, to study in detail, the environmental and health impacts of iron ore mining. The observations and results should give a better idea of how to use the element more efficiently. For example, even many decades back, a study of the health problems commonly associated with people working in iron ores showed significant results. A comparison of general illness patterns in normal people and those working in iron ores was made. In the survey region, it was seen that there was a whopping 42 deaths due to lung cancer in iron ore miners, in a 20 year period. After these results were published, protective methods of iron ore mining were in the making (Boyd, 1970). Recycling techniques improve utilization as discussed in the Appendix.
Conclusion:
Iron is a commonly used metal, which is available in plenty, and is inexpensive. It is also an essential nutrient required in living beings. However, excessive amounts can be toxic, and continuous exposure to iron ores may cause severe health problems. Just like any other resource, excessive extraction and depletion is not favourable for the future. A well regulated and continuously monitored process can help in sustainable utilization of the element.
Appendix: How Recycling Helps
One of the best ways of utilizing any resource is by finding an efficient way to recycle it. For example, coarse iron ore tailing of Minnesota’s Mesabi Iron Range is commonly used as the main raw material for construction of large dams used for tailing impoundments. Reclamation and recycling rules in Minnesota have helped in controlling erosion and in the safety and stability of dams (Norland, 1995). Similarly, a method to recycle wet steel making sludges to turn them into reverts having improved properties was proposed in 1998. A detailed 28 step process involving the recycling of slag/sludge mixture to make a productive steelmaking revert was patented. It was shown that the recycled steel was more corrosion resistant, and less reactive (Lynn, 1998). Many such findings over the course of time will lead to up-gradation of technology which is both, environment friendly, and prudent about the availability of natural resources.
References:
Galdon-Sanchez, Jose E., and James A. Schmitz. "Competitive Pressure and Labor Productivity: World Iron-Ore Markets in the 1980's." The American Economic Review 92.4 (2002): 1222-1235.
Schmitz Jr, James A. "What determines productivity? Lessons from the dramatic recovery of the US and Canadian iron ore industries following their early 1980s crisis." Journal of Political Economy 113.3 (2005): 582-625.
Boyd, J. T., et al. "Cancer of the lung in iron ore (haematite) miners." British journal of industrial medicine 27.2 (1970): 97-105.
Norland, Michael R., and David L. Veith. "Revegetation of coarse taconite iron ore tailing using municipal solid waste compost." Journal of Hazardous materials 41.2 (1995): 123-134.
Lynn, John D., Colvin W. Smith, and Glenn C. Keyser. "Method for recycling iron bearing sludges in a steelmaking operation." U.S. Patent No. 5,785,737. 28 Jul. 1998.
