Abstract: The invention relates to a mixing apparatus and a method for mixing gas in a closed mixing reactor, which uses gas as a process chemical with a high efficiency and where the content of pulverous solids in the solution is great. The aim is to obtain a flow in the reactor which sucks gas from above the surface of the liquid using rotating mixing devices in the centre of the reactor, and to mix said gas throughout the reactor capacity. The mixing apparatus of the invention comprises at least two mixers located at different heights, and on the same shaft. The upper mixer is equipped with a central plate attached to the shaft, with essentially vertical inner blades rising upwards and downwards and outer vanes directed outwards from the central plate, which are inclined from the horizontal. The lower mixer is equipped with a central plate attached to the shaft with vertical blades located on the outer edge.

Abstract: The invention relates to a mixing apparatus and a method for mixing gas in a closed mixing reactor, which uses gas as a process chemical with a high efficiency and where the content of pulverous solids in the solution is great. The aim is to obtain a flow in the reactor which sucks gas from above the surface of the liquid using rotating mixing devices in the centre of the reactor, and to mix said gas throughout the reactor capacity. The mixing apparatus of the invention comprises at least two mixers located at different heights, and on the same shaft. The upper mixer is equipped with a central plate attached to the shaft, with essentially vertical inner blades rising upwards and downwards and outer vanes directed outwards from the central plate, which are inclined from the horizontal. The lower mixer is equipped with a central plate attached to the shaft with vertical blades located on the outer edge.