Abstract: Emission gas to be scrubbed of sulfur dioxide or the like has turbulent lengthwise flow through an elongated mixing vessel. At a mixing zone in the vessel, near where said gas enters it, finely comminuted lime (Blaine Number preferably 6000 before calcining) is fed into the gas and carried out of the vessel with the gas to a cyclone separator. From the cyclone the gas passes to a baghouse at which residual lime is removed from it and it is released. A minor portion of the lime separated at the cyclone is sent to waste; most is returned to the mixing zone for recycling. Make-up lime is fed to the mixing zone from a suspension calcining furnace, reaching the mixing zone while still heated. To maintain 650.degree. C. to 750.degree. C. at the mixing zone, recycled lime may be reheated in passing from the cyclone to that zone.

Abstract: Emission gas to be scrubbed of sulfur dioxide or the like has turbulent lengthwise flow through an elongated mixing vessel. At a mixing zone in the vessel, near where said gas enters it, finely comminuted lime (Blaine Number preferably 6000 before calcining) is fed into the gas and carried out of the vessel with the gas to a cyclone separator. From the cyclone the gas passes to a baghouse at which residual lime is removed from it and it is released. A minor portion of the lime separated at the cyclone is sent to waste; most is returned to the mixing zone for recycling. Make-up lime is fed to the mixing zone from a suspension calcining furnace, reaching the mixing zone while still heated. To maintain 650.degree. C. to 750.degree. C. at the mixing zone, recycled lime may be reheated in passing from the cyclone to that zone.