A mixing apparatus 100 for mixing at least two fluids, the mixing apparatus 100 comprising a shaft 120 rotatable about its longitudinal axis 121, a first 122 and a second 124 radially extending impeller mounted on the shaft 120 and respectively axially spaced apart, characterised in that the first impeller 122 comprises a plurality of curved blades 125 operable to move said fluids in an axial direction towards the second impeller 124, and the second impeller 124 comprises a plurality of curved blades 125 operable to move said fluids in an axial direction towards the first impeller 122.