Why are active metals more difficult to process and refine?

Answer 1

The more reactive a metal, the greater tendency it has to form a positive ion in the context of a chemical reaction (e.g. Na => Na+ or Fe => Fe2+). This also implies that the reverse reaction becomes more difficult i.e. the more reactive a metal, the more difficult (and expensive) it is to extract from its ore and the metal is also more susceptible to corrosion with oxygen and water.

Titanium, for example, has to be cast in a vacuum.

Active metals once extracted and refined can then be hazardous - for example, lithium, sodium and potassium oxidise in the presence of water in a very exothermic reaction (causing fire/explosions!)

Answer 2

Active metals form very stable compounds as ores (meaning the strength of the bonds formed in their ores are very strong), hence the ores need more energy to be decomposed and thus to extract and refine the metals.
Eg. aluminium from molten bauxite, Al2O3
Aluminium being reactive forms very stable oxide - Al2O3. The oxide is very resistant and stable to heating thus electrolysis is used to decompose the oxide.
On the other hand, iron can be extracted from haematite (Fe2O3) as iron is not a reactive metal and its compounds are less resistant to heating. Thus heating in a blast furnace, with lost of coke, is sufficient to get the metal iron.
Hope this helps :)

Answer 3

Because they chemically react more readily with other elements as compared to other metals.