Iron in its pure state is soft, malleable and ductile (that can be stretched, drawn or hammered thin without breaking ((Webster’s Dictionary, 419, 1988)) with a hardness of 4-5. It is easily magnetized at room temperatures and this property disappears when heated above 790 degrees Celsius.. Metal iron occurs in a free state in only a few localities, notably Greenland (Encarta, 1996). One of the physical properties of iron as an ore is its color which can be black, brown or even reddish. Hematite is the most important iron ore, commonly occurs as “kidney ore” – so -called because of its shape (Symes, 1988, 56). Other ores included goethite, magnetite, siderite, and bog iron (Encarta, 1996). Even though iron is tough and hard it is still easy to work. Iron is a active metal and will combine with halogens, carbon, etc. It has an atomic weight 55.847, it’s atomic number is 26, it’s specific gravity is 7.86, it’s melting point is 1535 degrees Celsius, and it’s boiling point is 3000 degrees Celsius. It burns in oxygen forming ferrous oxide. When exposed to moist air, iron becomes corroded, forming a reddish – brown, flaky, hydrated ferric oxide, commonly known as rust. (Encarta, 1996)
铁形成在浅海中。它从水中排出并在海底上收集。这会产生水下存款。这
流程发生在数十亿年。通过板式运动整个海底最终被搬出水。一旦出水，铁已经形成了土地沉积物。美国最大的铁矿床是在大湖泊中。北明尼苏达州通常被称为铁场。有两种方法是铁存款所在的。在第一种方法中，使用检测铁的磁力的特殊机器，TI可以找到沉积物。在第二种方法中，具有特殊设备的平面在涉嫌具有矿石沉积物的土地面积上飞过并射击声波以确定该区域是否包含铁沉积物。波浪回到平面上并由图案确定一个可以辨别出熨斗沉积物。
在1990年代早期，美国铁矿石的年产量超过5600万吨（Encarta，1996）。有两种方法在开采铁。这两种方式是露天坑和井挖掘。露天采矿用85％的浅沉积时间。露天挖掘也是呼叫剥夺矿业。露天坑开采的方式是顶部土壤被推土机移除，土地向下铺设。然后矿工掀起了一个大爆炸，散落并松散了矿石。矿石的卡车被带到表面上。由于坑更深，更深层次的费用增加，并在某些时候进入第二种采矿方法是更经济的。铁被开采的第二种方法称为轴挖掘。 Shaft mining is usually used for deep and concentrated iron deposits. The way shaft mining works is that a large machine crushes the rock and then conveyor belts are used to transport it up to the surface.
精炼的定义是做好或纯净;没有杂质;渣滓，合金，沉积物等。当它们将铁完善时，它们用其他金属合金合金。这产生了一种称为钢的非常常见的金属。钢是非常广泛的。它是从制作建筑物来制作单螺钉。虽然有人可能思考，因为钢是由精制铁制成的，属性将是相似的。这是假的。与汽油是精制油的相同。人们可能认为他们非常相似，但它们非常不同。
采矿被认为对环境非常有害。露天矿业对周围环境留下了重大影响。大面积的土地实际上是挖掘，留下了大型创造者。巨大的洞扰乱了环境，并不是美学。然而，一些凹坑，例如明尼苏达州Mesabi系列的坑已经变成了湖泊，这为鸟类，鱼类和其他野生生活的栖息地创造了娱乐区。大型机器的噪音和采矿中的频繁爆炸必须吓到大部分动物生活。炸药爆炸的烟雾产生极其有毒气体，并且可以释放有害物质的采矿口袋。采矿过程中产生的灰尘会导致疾病，尤其是肺病;黑肺病主要与煤矿相关联。在轴采矿中，气体可以积聚和爆炸可以产生。 Shafts have also collapsed killing workers. Refining of the ore causes dust and fumes to be released into the environment. In the smelting process to make steel, acidic clouds are formed from the burning of coal. In the U.S., scrubbers are required in smoke stacks to prevent acid rain. Through the years, iron and steel have been used to build our country and provide employment. It’s hard to imagine what life would be like if man had not learned how to mine and manufacture iron. Mining is now done in a manner to conform more to the environment.
一旦将铁矿石开采，它将被炼油净化并纯化。来自明尼苏达州北部的大部分铁在德卢斯的驳船上装载在驳船上，并通过大湖泊运送到宾夕法尼亚附近的港口，如伊利，然后运到匹兹堡和伯利恒等城市。运送它在这里比运送煤炭在此过程中使用的煤炭制造钢材更容易。纯铁使用非常有限。它用于生产镀锌金属板和电磁铁。商业上使用的大部分铁含有少量的碳和其他杂质。这包括锻铁，铸铁和钢铁。冶炼用于生产这些早期形式。如今，使用空气爆炸用铁用铁合金加热铁的高炉生产钢。（Encarta，1996）。 The steel is then shaped into screws which are used to hold the face mask on the shell of the football helmet. Steel is used for this purpose due to its strength. The physical properties of iron are totally changed once it has become steel and therefore good to make screws as it will no longer rust.
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