An electro-static device for mixing and blending accurately metered streams of finely divided particulate matter is disclosed. The device comprises an electro-static conveyor and at least two electro-static metering devices. The electro-static metering device can be used separately from the electro-static conveyor - for instance, with an electro-static sieve. Additionally, two improvements applicable both to electro-static conveyors and to electro-static sieves are disclosed.