Abstract: At least one absorbent is added to the exhaust gas, which is passed at temperatures in the range from about 40.degree. to 500.degree. through a fluidized bed reactor and through dedusting means. Part of the solids separated in the dedusting means is recycled to the fluidized bed reactor. At least part of the recycled solids is blown with an entraining gas upwardly through a tube into the lower portion of the reactor. At least part of the combustion exhaust gas is fed to the reactor as a rising stream from a space which surrounds the tube. Air or combustion exhaust gas may be used, e.g., as an entraining gas.

Abstract: A combustion exhaust gas which is to be dedusted and denitrated is mixed with NH.sub.3 and at temperatures in the range of about 250.degree. to 600.degree. C. is passed through a fluidized bed. The fluidized bed contains a denitrating catalyst, which contains FeSO.sub.4. The combustion exhaust gas serves as a fluidizing gas in the fluidized bed. Fresh denitrating catalyst is supplied to the fluidized beg and comprises at least 90% by weight FeSO.sub.4, which contains water of crystallization and has particle size in the range from 1 to 150 micrometers. The treated exhaust gas is dedusted in an electrostatic precipitator.

Abstract: The process of removing dust, sulfur compounds and nitrogen oxides from combustion exhaust gases, comprising mixing a combustion exhaust gas with ammonia; feeding Ca(OH).sub.2 and FeSO.sub.4 to a fluidized bed reactor containing mixed solids including fly ash, iron sulfates and calcium compounds, especially Ca(OH).sub.2, CaCO.sub.3, CaO, CaSO.sub.4 and CaSO.sub.3 ; supplying an ammonia-containing exhaust gas mixture to the fluidized bed reactor as a fluidizing gas; operating the fluidized bed reactor at a temperature between 300.degree. and 450.degree. C. to form a reacted exhaust gas; supplying the reacted exhaust gas to a multistage electrostatic precipitator having a first stage and additional stages; recycling solids collected in the first stage to the fluidized bed reactor; and recycling one portion of additional solids collected in the additional stages to the fluidized bed reactor and discharging another portion of the additional solids.

Abstract: For a treatment of the residues which become available as dry dust in the purification of exhaust gas and contain, inter alia, 5 to 12% by weight CaO and have a conductance in excess of 6000 .mu.S/cm, a process is proposed in which the residues are fluidized with purified exhaust gas in a circulating fluidized bed system consisting of a fluidized bed reactor, separator and recycling line and the CaO contained in the residues is reacted with the CO.sub.2 contained in the exhaust gases to form CaCO.sub.3.

Abstract: Zinc and, if desired, lead are volatilized from a metallurgical material such as a finely divided oxidic ore, ore concentrate or another metallurgical intermediate. The volatilization of the zinc is carried out at a temperature above 1300.degree. C. in a cyclone chamber which has an axis that is substantially horizontal, i.e. is inclined to the horizontal at an angle of 0.degree. to 15.degree.. Carbon dioxide is removed from the gas leaving the zinc condensing stage and the high carbon monoxide gas thus obtained is recycled to the cyclone chamber or at another point ahead of the condensation stage.

Abstract: A process for thermally treating fine-grained solids with high-oxygen gases at temperatures at which the solids can form molten and gaseous reaction products comprises carrying out the thermal treatment in a cyclone chamber and thereafter conducting the gases from the cyclone chamber into a horizontal or vertical cooling chamber. The process can be used for the roasting of sulfide ores, ore concentrates and other metallurgical intermediate products. The outlet of the cyclone chamber through which the gases are removed lies approximately along the axis and cooling is carried out in the cooling chamber such that the molten droplets contained in the gas stream entering the latter are cooled in free flight below their solidification point in the gas, i.e., do not contact the walls of the cooling chamber until they are solidified at least along their surfaces.

Abstract: A process for thermally treating fine-grained solids with high-oxygen gases at temperatures at which the solids can form molten and gaseous reaction products comprises carrying out the thermal treatment at least in part in a cyclone chamber. The solids, high-oxygen gases and, if desired, an energy carrier (usually a carbon-containing solid, liquid or gas) are mixed to form a suspension at a temperature below the reaction temperature. The suspension is fed to a vertical combustion path (tube) and reacts therein to form another suspension of primarily molten particles which is admitted to the cyclone chamber. Reactants are added to the gas phase within a core-flow region of the cyclone chamber and/or immediately after the discharge of gas therefrom to a cooling chamber.