"Analyses identified other metals, such as aluminium, calcium, zinc, iron, uranium, and rare earths as well as fluoride and oxygen in solids generated during the treatment of the effluents A1 and A2.Figure 5: Micrographs, 8000X, of precipitates obtained by manganese oxidation by KMnO4 at pH 7.0: (a) MnSO4 solution; (b) effluent A1; (c) effluent A2.3.5." . . . .