Evaluation of The Best Method for Aluminum Production

Aluminium: Electrolysis, Smelting, or Recycling?

Aluminium (Al) is a chemical element that is part of the boron group, and is the most abundant metal in the Earth’s crust. Aluminium is the second most used metal after steel and is used for construction, packaging, household utensils, sporting goods, and in the automotive industry. In 2009, over 3.4 million tons of aluminium was deposited in the United States’ waste stream regardless of recycling efforts. This essay will discuss the different options of producing aluminium, such as electrolysis, smelting, and recycling.

Extracting aluminium is expensive, mainly because of the consumption of electricity that aluminium smelters consume. Aluminium forms strong chemical bonds with oxygen (aluminium oxide or alumina), and in order to separate the elements, electricity must travel through it. Alumina is extracted from the ore known as bauxite, and the bauxite is purified to produce alumina in order for the aluminium to be extracted. The electrolysis of alumina is done in carbon-lined steel cells, in which an electric current passes. The aluminium oxide is dissolved in molten cryolite, a compound of aluminium and sodium fluorides (Na3AlF6) with a melting point of approximately 960°C. At the bottom of each pot, the negative electrode (cathode) and positive electrode (anode) are made of graphite, a form of carbon. Inside the pot, the alumina is dissolved in a molten electrolyte, and its ions are free to move around. The aluminium ion is being reduced: Al3+ + 3 e− → Al, and at the positive electrodes carbon dioxide is formed: 2 O2− → O2 + 4 e−. Eventually, the carbon anode is eradicated and the positive electrodes have to be replaced regularly, which becomes expensive.

Aluminium smelting is the process of extracting aluminium from its oxide, generally by using the Hall- Héroult process. The Hall- Héroult process involves dissolving alumina in molten cryolite and electrolysing the molten salt bath, typically in a purpose-built cell. An aluminium smelter consumes so much electricity that they are usually built near hydroelectric power stations. A large quantity of carbon is released during the smelting process and as a result, there are frequent GHG emissions. The Hall-Héroult electrolysis process is the major production route for primary aluminium.

The extraction of aluminium has both its advantages and disadvantages. Aluminium extraction consumes approximately 5% of the electricity generated in the United States. The cost of melting the aluminium, and the supply of electricity needed for electrolysis is very high, and this is why smelting sites are constructed in areas where electricity is cheap. It is a continuous and efficient process, and the resulting aluminium has a purity of 99.99%. Furthermore, the process of extracting aluminium also means that a large quantity of fluoride is wasted. Unless manufacturers are careful with the waste, hydrogen fluorides are very dangerous because they are toxic to vegetation and the environment. However, most companies are not environmental-friendly because cleaning after the extraction is time consuming and costly.

Aluminium recycling dates back to the early 1900s, and is still done today for sources such as aircrafts, automobiles, computers, cooking ware etc. Recycling aluminium involves a simple process of re-melting the metal, which is less expensive and energy intensive than producing new aluminium through electrolysis, and mining bauxite ore. Recycling aluminium only requires 5% of the energy used to produce new aluminium from bauxite ore, and aluminium is 100 per cent recyclable. Recycling 1 tonne of aluminium saves 9 tonnes of CO2 emissions. So why don’t more companies recycle aluminium if it’s the best option for the environment? Because the cost of labourers and machinery to recycle all the waste deposited in landfills is too high and most companies only focus on producing as much aluminium as possible. However, in 2009, Brazil was recorded to have recycled 98.2% of their aluminium can production and today, other countries are beginning to recycle more.

Conclusively, I personally believe that recycling is a better option than constantly producing new aluminium through electrolysis, mining bauxite ore and allowing hydrogen fluoride to be part of landfills. Although recycling is expensive, and this is the main reason why manufacturers are rarely cleaning after the extractions, destroying the environment should not be an option. I only see positive aspects when it comes to the idea of recycling aluminium. However, I do understand that there is always a limit when it comes to spending money and companies usually choose the option that’s beneficial for them and their consumers. After researching and reading about different viewpoints on this matter, it is evident that experts are still finding a solution to balance the impact this has socially, economically, politically, environmentally, culturally and morally on the world. I hope that one day there will be a solution to this problem because the environment is gradually being destroyed.