- Noise pollution
- Dust pollution
- Traffic congestion
- production of bacteria, germs and insects around which can be harmful for people
- affects the weather of the surrounding
Environmental:
Advantages -
- Can be reclaimed as an animal sancturay or a tourist attraction/ lake E.g the eden project
Disadvantages:
- Air pollution from machinery
- Disrupts the ecosystem
- Kills wild life
-Scar’s the landscape
Quarrying is necessary exercise in the modern day 21st century, providing much of the vital materials used for everyday life. Such metals that are mined range from; molybdenum, silver, lead, copper, and gold and of course, iron. However, like many other man-made activities, quarrying causes a significant impact on the environment. In particular, it is often necessary to blast rocks with explosives in order to extract material for processing but this method of extraction gives rise to including noise pollution, air pollution, damage to biodiversity and habitat destruction.
The four stages of extraction
First of all, the ore is mined, using various techniques, in which are called primary crushing, secondary crusher and tertiary crushing. Through the whole process, the ore is broken fragmentary no more than alternate 1 m, then after, fine crushed, screened into ore size less than 12mm, therefore leaving the final product sent through grinding slots. The mining ore general equipment is the jaw crusher (which basically grounds the ore which is transported straight from the ground), next the cone crusher is used ( for increasing the production capacity), then the hydraulic impact crusher (used to eliminate sediment from the iron), and finally the grinding mill is brought into the overall method.
The ore is then converted into the metal via the blast furnace or the method of electrolysis:
Blast furnace:
Common iron ores are hematite (Fe2O3) and magnetite (Fe3O4). Since, iron is below carbon in the reactivity series, iron in the ore is reduced to iron metal by heating with carbon (coke). It is actually carbon monoxide which does the reducing in the blast furnace.
Iron ore is reduced to iron by heating them with coke (a form of carbon) in blast furnace. The iron ore contains impurities, mainly silica (silicon dioxide). Limestone (calcium carbonate) is added to the iron ore which reacts with the silica to form molten calcium silicate in the blast furnace. The calcium silicate (called slag) floats on the liquid iron.
The air blown into the bottom of the blast furnace is heated using the hot waste gases from the top. Heat energy is valuable, and it is important to conserve heat energy. The coke (produced by heating coal in the absence of air) burns in the blast of hot air to form carbon dioxide; exothermic reaction releases heat. This reaction is the main source of heat in the furnace.
C + O2 = CO2
At the high temperature at the bottom of the furnace, carbon dioxide reacts with carbon to produce carbon monoxide.
C + CO2 = 2CO
It is this carbon monoxide which is the main reducing agent in the furnace to produce iron.
Fe2O3 + 3CO = 2Fe + 3CO2
In the hotter parts of the furnace, the carbon itself also acts as a reducing agent. Notice that at these temperatures, the other product of the reaction is carbon monoxide, not carbon dioxide.
Fe2O3 + 3C = 2Fe + 3CO
The temperature of the furnace is hot enough to melt the iron which trickles down to the bottom as ‘pig iron’, where it can be tapped off.
The limestone is added to convert siliceous impurities into ‘slag’ ( as calcium silicate, CaSiO3), which melts and runs to the bottom. The calcium silicate melts and runs down through the furnace to form a layer on top of the molten iron.
CaCO3 + O2 = CaO + CO2. CaO + SiO2 = CaSiO3
Electrolysis:
Electrolysis of iron ore is the least developed process route currently being studied in ULCOS. This process would allow the transformation of iron ore into metal and gaseous Oxygen(O2) using only electrical energy.
Producing iron by electrolysis would mean that coke ovens and the reactors used for reducing the iron ore, such as a blast furnace, would no longer be required. The Carbon dioxide(CO2) created during these processes would also be eradicated leaving a Carbon dioxide(CO2) lean process of iron making.
Although no iron is presently produced industrially by electrolysis, many reasons stand in favour of this technique for industrial application. Electrolysis is, for example, a well established technique developed at an industrial scale in metal production of aluminium, zinc or nickel.
Thirdly, reduction of iron. All steelmaking processes require the input of iron bearing materials as process feedstock. For making steel in a basic oxygen furnace, the iron bearing feed materials are usually blast furnace hot metal and steel scrap. A broadly used iron source is also a product known as Direct Reduced Iron ("DRI") which is produced by the solid state reduction of iron ore to highly metallized iron without the formation of liquid iron. This solid state reduction of iron ore is also called ‘sponge iron’.
The uses of iron in the form of steel
Iron in the form of steel is used on a regular basis all around the globe. For example, a shovel (for agriculture), or a pocket watch, even forming parts of an electric guitar. Iron is the 6th most common iron in the universe to date. Machines, vehicles and building structures are commonly built from iron. The Iron Age was a prehistoric time when useful tools and weapons were first made from iron and steel. The dates this occurred in various parts of the world varies, with historians suggesting around 12th century BC in ancient Greece and 6th century BC in Northern Europe.
Recyclable iron
The metals are collected and then melted at high temperature. They then have any impurities scraped off the top of the container of molten metal. The pure molten metal is then poured into casts and cooled. The blocks of metal can now be used again.
It is cheaper and less environmentally damaging to recycle metals rather than extract them from their ores, in the ground.
Conclusion
Metal's application to buildings began as an essential decorative or practical role rather than structural. Wrought iron nails, hinges and other necessary components were the most common forms but lead and copper were also used for roof coverings. More skilled use of wrought iron was made in the provision of decorative elements of buildings but the structural use of iron only began in the late 18th century with Abraham Darby's Iron Bridge made entirely of iron arches and ribs cast in a foundry and transported to the building site for assembly. Although this advertised iron's remarkable architectural capabilities few architects designed buildings constructed entirely of this material. This is just one reason why iron has been and will be in the foreseeable future, the main component of the construction material family.