Skip to content
Skip to main content

About this free course

Download this course

Share this free course

An introduction to geology
An introduction to geology

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

2.6 Getting bauxite from soda cans

A typical bauxite ore is 50% Al2O3. Remember, Al has an atomic mass of 27, O is 16, so bauxite is 26.5% Al. Using this information, see if you can complete the activity below. Again, don't worry if you have some difficulty with this – it takes some practice.

Activity _unit2.7.1 Activity 2.1 Extracting Al from bauxite

Timing: Allow about 10 minutes

a. 

134 g


b. 

56.7 g


c. 

30.1 g


The correct answer is b.

Answer

The answer is 56.7 g bauxite:

50% bauxite is 50% Al2O3.

50 postfix times percent cap a times l sub two times cap o sub three times prefix multiplication of 54 divided by 102 postfix times postfix times equals percent cap a times l

equation left hand side 15 times g times cap a times l divided by 26 times eight divided by 17 postfix division 100 equals right hand side 56 postfix times two divided by three times g postfix times cap b times a times u times x times i times t times e postfix times

So it’s around four times more efficient to use bauxite as a source of Al than a typical igneous rock like granite – and that’s because the geological process, in this case weathering, does a lot of the work for us.