Method for operating a multi-cyclone for the separation of fine and very fine grain as well as a multi-cyclone

The invention relates to a multi-cyclone and to a method for operating such a multi-cyclone for separating fine material and very fine material. In this context, a multi-cyclone according to the invention has multiple individual cyclones which are of essentially identical construction and which are housed in a housing that has an upper and a lower chamber. Via a supply into the lower chamber it is possible to introduce in a targeted manner cyclone regulating air which can be used to set the quantity, the fineness and/or the purity of the material separated by means of the multi-cyclone.