Abstract: A method and system for removing sulfur and dust from waste gases, particularly refinery waste gases, wherein the waste gas to be cleaned is passed to a scrubbing tower above a scrubber sump and, in order to remove SO2 and acidic gases, scrubbed in a scrubbing zone of the scrubbing tower, in counter-current with a scrubbing fluid that is drawn from the scrubber sump and passed to spray nozzles at the upper end of the scrubbing zone. Sulfites contained in the scrubber sump are oxidized to form sulfates, by means of gasification with air in the scrubber sump or in an external device assigned to the scrubber sump. A suspension stream is drawn from the scrubber sump. The gas that leaves the scrubbing zone flows through a wet electrofilter arranged above the scrubbing zone in the scrubbing tower, whereby dust particles and aerosols and entrained droplets are collected on precipitation electrodes of the wet electrofilter.

Abstract: Roasting of ores with metal values such as precious metal ores for recovery of metal values with conversion of arsenic to an insoluble form in-situ in presence of an additive such as iron and in presence of oxygen injected initially or supplementally in a roaster such as in a circulating fluid bed roaster; volatilized arsenic in roasting of ores may also be converted to an insoluble form in gas phase in a two stage roaster process after removal of solids from a gas phase and contact with an additive at high oxygen concentration in a second stage roaster.

Abstract: Refractory gold ores are roasted in the presence of added fuels in an oxidizing atmosphere in a fluidized bed at a temperature from 450 to 650° C., which is supplied with oxygen-containing gases; to achieve a low ignition and thus low roasting temperature, sulfur, pyrite or mixtures thereof are used as added fuels.

Abstract: Organic and/or inorganic substances and water are thermally separated from contaminated materials, solid aggregates, the contaminated material is pretreated and is subsequently heated in a directly or indirectly heated furnace, which includes a rotary kiln, a fluidized bed furnace or a floating zone reactor, and during the heating the material is treated with recycled hot gases or recycled hot steam and with oxidizing agents. The exiting processing gases, which contain water vapor, are dedusted, and 80 to 90% by volume of the water vapor-containing processing gases are recycled to the furnace to act as entraining gas. The remaining water vapor-containing processing gases are condensed, the resulting liquid phase is withdrawn, and pollutants are removed from the withdrawn liquid phase by a wet chemical or physical processing.

Abstract: Granular coal is combusted in a circulating fluidized bed system comprising a combustion chamber, a separator and a recycle line for recycling solids from the separator to the combustion chamber. Gas from carbonization is added to the oxygen-containing combustion gas withdrawn from the combustion chamber and is at least partly combusted in said combustion gas to increase the temperature of the combustion gas to about 850.degree. to 1200.degree. C. The gas from carbonization is produced by the heating of granular coal.