Extraction of Aluminium This work is available on a CD, with model Q&A. Unlike here in a CD it looks better all the equation and symbols come correctly [subscripts and superscripts]. When you get the CD all you got to do is to print it out to get a perfect set of notes, model Q&A and Q&A from past exam papers. All this work is given for a small fee, at the price of A TAKEAWAY because I need to help the children who want to learn. The reason I went to do this INTERNET TUITION because the price can be kept very low, affordable to children and mums and dads who pay for the tuition. Private tuition CD is made to you for £7.50 so what do you want in it?
Question 4) a) : Describe the process of extraction of Aluminium.
Answer 4) a) : How Aluminium is extracted.
The process of extraction of Aluminium is called electrolysis. The word itself ‘LYSIS’ means breaking down, electrolysis means BREAKING DOWN BY ELECTRICITY. Bauxite, Al 2 O 3 2H 2 O is roasted to remove water and the substance obtained is anhydrous Aluminium oxide of the formula Al 2 O 3 . Bauxite is the ore of aluminium found near the surface of Australia, Guinea, Brazil and other countries. It is extracted by open cast mining. They leave huge gaps of excavation holes; they are sometimes even 60 metres deep. An impurity found in Bauxite is Iron (III) oxide, which is red. After separation from the Bauxite, the red mud is pumped into ponds, which become unsightly red mud ponds. This is seen near Quebec in Canada. This red mud cannot be pumped into the sea because it would harm the fish. These are some of the problems with aluminium extraction. Bauxite has nearly 60% of aluminium oxide and Al 2O 3 is commonly known as Alumina. During electrolysis, Alumina, Al 2O 3, and Cryolite Na 3 AlF 6 and fluorspar CaF 2. This mixture was discovered in 1886 by an American and a Frenchman, their joint discovery dropped the price of Aluminium by 90%. From that time aluminium was no longer regarded as a precious metal, and came into wide spread use. Because of the electrolyte it was electrolysed at a temperature of 950 degrees C, but before that, pure Alumina had to be extracted at 2040 degrees C, which is the melting point of Aluminium. That means less current at a low temperature aluminium could be extracted, that is the reason the price came down. It has a high melting point about 2050c 0 and pure Al cannot be easily obtained by reduction. Hence anhydrous Aluminium oxide [Alumina] is dissolved in an electrolyte called Cryolite [Na 3 AlF 6] and extracted at a temperature below 1000c. 0
Question 4) b) : What is Cryolite?.
Answer 4) b) This is an electrolyte added in the extraction of Aluminium. The formula of cryolite = Na 3 AlF 6 .
Extraction of Aluminium
In GCSE one has to know the useful Products from Rocks and they are the extraction of:
1] Iron.
2] Aluminium.
3] Copper.
Both of them have been covered under Electrolysis in my Q&A book but let me give some work for FREE. In exams they are going to ask key points such as follows:
If you go to some textbooks they give very colourful glossy pictures then you think, “This is value for money” and buy them. Please don’t expect colourful pictures in my book, the exam papers are not asking colourful diagrams but they ask questions to the point and I have made every effort to meet these requirements. All catalogues have glossy colourful pretty pictures with over 1000 pages and some textbooks are heavy with lots of pages, made attractive to the consumers and it is up to the consumers to choose. I heard the old saying, “Don’t judge a book by its cover”, it’s true.
You must read the interview made by a leading London journalist about my book and the work, to judge my work and the book. It is found in many search engines and one of them is www.lankaeverthing.com . There go to the section called lankan front lines and look for my name as Dr Hector Perera. That interview is also available in www.infolanka.com/org/diary.
Let me give the work from next page.
Extraction of Aluminium
Ore of Aluminium : BAUXITE, Al 2 O 3 2H 2 O
Source of energy : Electrical.
Temperature : 1000 c 0 .
Process : By Electrolysis.
Electrolyte : CRYOLITE, Na 3 AlF 6
Electrode reactions [ What happens at each electrode]
Cathode reaction [ Negative electrode ]
2Al 3+ + 3e à Al
Anode reaction [ Positive electrode]