Describe Phytoextraction and it's Process

It Makes use of plants absorbing mineral ions through their roots: 1) plants are grown on a low-grade ore 2) plants absorb metal ions through their roots and concentrate these ions in their cells 3) then are harvested and burnt 4) the ash left behind contains metal compounds Process is slow but: - reduces the need to obtain new ore by mining - conserves limited supplies of high-grade ores - reduces the amount of rock waste that must be disposed of after traditional mining