how we purify metals like aluminum and titanium once mined?
In: Technology
Different metals melt at different temperatures. So we heat them and separate them, repeat until what you have left is what you wanted.
Answer:
Aluminium isn’t mined, it’s too reactive with other elements to be found wild in nature except for a few rare cases where lightning hit the earth creating natural aluminium.
Bauxite is what we mine, which is then turned in to Alumina also known as Aluminum Oxide.
Then Alumina is turned in to Aluminium using an Electrolysis process. Where Alumina is dissolved in a bath or sodium aluminum fluoride using a very strong current. This bath is a continuous process which can not be shut down and restarted once started, so once an aluminum oven has been started up it has to run for close to a decade before it gets replaced. The aluminum is regularly extracted from this bath, about once per day per oven.
And as long as the ore is high quality it’s fairly pure once it’s extracted. But it will contain particles which need to be removed for most uses. This happens using various cleaning processes such as removing the slag which floats to the top of the oven, passing it through inert gas filters which use argon to make the particles float to the surface, and ceramic filters which “large” particles can’t pass through but pure aluminium can’t.
It’s very difficult to get extremely high purity aluminum, especially iron is a contaminant which is close to impossible to get rid of. So aluminium with a low iron content is of very high value.
It’s like a cake recipe. Add the right chemicals and bake with lots of electricity, and it’ll melt and separate from the rocks.
Since Aluminum is already answered here is the process for titanium in short:
The most common titanium containing minerals are Rutile and Ilmenite
Ilmenite is first turned into Titanoxide (Rutile is one already) by extracting the iron part, for example with sulfuric acid.
Then under hot temperatures it’s reacted with chlorine and coal to titantetrachloride (and carbonmonoxide).
In the last step you remove the chlorine again by reducing it with liquid magnesium or sodium
We cook the rocks and gather the hot rock sweat. Different rocks sweat different metals and use different kinds of rock cookers.
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