Large scale extraction of minerals (metal compounds) from the earth to make metals using traditional mining techniques is only cost effective when there are high concentrations of the mineral in the ground. We call such a mineral, a _________________________. When there are only small amounts of mineral in the ground, called a _______________________, then a process called _______________________, involving growing plants, is economic to use. Plants called ___________________________ are grown in soil containing the low grade ore minerals. They absorb the minerals via their _____________ and what they don't use is stored and _________________________ in their leaves. When the plants are big enough, they are ______________in air and the impure metal compound is found in the _______________. Chemical processes such as __________________________ and __________________________ are used to then purify the metal from the ash.

Word bank
☐ ash
☐ concentrated
☐ electrolysis
☐ hyperaccumulators
☐ phytomining
☐ burnt
☐ displacement
☐ high grade ore
☐ low grade ore
☐ roots