Abstract: The hot raw gas, which contains slag droplets is conducted downwardly in an entrance chamber of a slag separator through a first bed of packings into a flow-deflecting space, in which the raw gas is upwardly deflected and then flows upwardly in an exit chamber through a second bed of packings to a gas outlet. The effective velocity of flow of the raw gas in the first bed is 1.5 to 10 times its effective velocity of flow in the second bed. Liquid slag is drained from the flow-deflecting space.

Abstract: The process for purifying gypsum suspensions, particularly those formed in a flue gas desulfurizing plant, includes feeding the gypsum suspension (9) to a first hydrocyclone (1), which is operated to produce an underflow (11) with a comparatively high underflow concentration and an overflow fed to a collecting tank (2). The underflow (11) of the first hydrocyclone stage is further diluted to a form another underflow with a lower solids content in a suspension tank (3) and then is fed to a second hydrocyclone stage (4), the overflow of which is also fed to the collecting tank (2). Depending on purity of the gypsum required or attained, the gypsum contained in an underflow (14) of the second hydrocyclone stage (4) is either immediately dewatered and removed or is first fed to one or more hydrocyclone stages, which operate analogously. The combined overflows (15) of the first and second or further hydrocyclone stages are fed from the collecting tank (2) to a third hydrocyclone stage (6).

Abstract: The tubular heater comprises numerous tubes, which are disposed in a combustion chamber and contain catalyst. A synthesis gas, which mainly comprises hydrogen, carbon monoxide, and carbon dioxide, is prepared in the tubes. There is a risk of a formation of carbides (metal dusting corrosion) on the outside surface of the outlet ends of the tubes. To prevent such corrosion, a gaseous or vaporous protecting fluid, which is substantially free of CO, is supplied to the region surrounding the outlet ends of the tubes.

Abstract: In a process for the recovery of silver by flotation from the residue from the wet extraction of zinc, the residue from the neutral wet extraction of zinc, the residue from the neutral wet extraction of zinc is recovered and is subsequently ground in an attritor and the residue which has been ground in an attritor is subjected to a flotation.

Abstract: A sinterable mixture comprising iron-containing materials and solid fuel is sintered on a sintering machine; to decrease the rate at which exhaust gas is to be removed and to produce a desirable sinter, a part of the exhaust gas is enriched to an oxygen content of up to 24% by the addition of higher-oxygen gases and is then recirculated as a recycle gas, and exhaust gas is removed as a tail gas from the process only at a rate which corresponds to the rate of the gas which is formed during the sintering process plus the rate of the gas added for enriching plus the rate of inleaked air which has infiltrated from the outside minus the rate of oxygen consumption.

Abstract: Residual metallurgical materials which contain zinc and lead are reprocessed by a thermal treatment in a circulating fluidized bed. The required heat is generated in that solid carbon is combusted in the fluidized bed reactor of the circulating fluidized bed. A solid carbon content of 5 to 30% is maintained in the lower part of the fluidized bed. Oxygen-containing gases are supplied to the upper part of the fluidized bed reactor, and CO.sub.2 is formed only in such an amount that zinc metal will not be reoxidized. Substantially all solids are removed from the discharged suspension in a recycle cyclone and are recycled. The gas is cooled to a temperature at which zinc metal is oxidized to ZnO. The dustlike compounds of zinc and lead are separated from the gas.

Abstract: An aqueous ammonium alum solution which contains Fe.sup.3+ ions and has a pH not in excess of 5 is passed through at least one half of the Fe.sup.3+ ions in the solution to Fe.sup.2+ ions. The solution is cooled and ammonium alum is crystallized whereas the Fe.sup.2+ ions remain in the liquid phase.

Abstract: A method for processing waste sulfuric acid which is contaminated with halides and has an acid content up to 40% which comprises subjecting the waste sulfuric acid to an electrodialysis in which the electric field causes the univalent halides to permeate through an anion exchange membrane and to be selectively removed while the divalent sulfate ions of the sulfuric acid are substantially retained, the sulfuric acid leaving the electrodialyzer being almost entirely free of halides. A corresponding apparatus is also provided.

Abstract: The invention describes a process for the manufacture of steel with a carbon content of <0.8 wt.-% by reducing iron ore and refining the hot metal. Iron ore and fuel are introduced into the reduction zone of a reactor that contains an iron melt in the reduction zone. This melt is covered by a liquid slag layer from which liquid slag is withdrawn. Further, oxygen-containing gas together with fuel is blown into the iron melt contained in the reduction zone. The iron melt extends into the refining zone of the reactor, the slag layer flows from the refining zone into the reduction zone and in the refining zone liquid steel is withdrawn. Oxygen-containing gas is supplied to the iron melt contained in the refining zone and liquid iron is withdrawn therefrom.

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: The tubular tool for use in effecting a gas exchange in multiplate insulating glass units provided with a sealant spacer has a sharpened end (1) like a plug drill and is provided with a handle portion (2) at the other end. The handle portion (2) has a port (3) for connection to a device which exchanges gas in a space between glass plates of the insulating glass unit. The wall of the tubular tool (20) is provided with throughgoing openings (4) in a portion between the sharpened end (1) and the handle portion (2). The tubular tool also can have a portion without throughgoing openings having a length approximately equal to a thickness of the sealant spacers both at the sharpened end and at the handle portion.

Abstract: In a process for a selective flotation of a copper-lead-zinc sulfide ore the raw ore is ground and slurried with water and the resulting suspension is aerated with air to adjust a certain oxidation-reduction potential and is subsequently successively conditioned with SO.sub.2, Ca(OH).sub.2, and collecting and frothing agents, whereafter a flotation of Cu is effected. An oxidation-reduction potential which is 70 to 90% of the oxidation-reduction potential desired for the flotation of Cu is adjusted by the aeration of the suspension with air before the flotation of Cu, the desired oxidation-reduction potential of 60 to 340 mV is adjusted during the flotation of Cu by the aeration with air, the flotation of Cu is effected at a pH of 8.5 to 10.5 and Cu is removed from the flotation process with the froth.

Abstract: For the separation of dioxins and furans from exhaust gases from combustion plants, particularly from refuse incinerating plants, a process is described in which the dust and the gaseous pollutants HF, HCl, SO.sub.2, and SO.sub.3 are first substantially entirely separated from the exhaust gases in known manner, the thus prepurified exhaust gas is then supplied to a wet-process electrostatic precipitator, and 10 to 500 mg activated carbon powder per sm.sup.3 are added to the prepurified exhaust gas immediately before it enters the wet-process electrostatic precipitator.

Abstract: To process vanadium-containing residues, the residues are leached in an aqueous slurry with introduction of SO.sub.2, the undissolved solids are removed. To effect a processing which is simple, economical and ecologically satisfactory, vanadium content is precipitated as a tetravalent vanadium compound from the sulfate solution at a pH from 7 to 9 by an addition of alkali metal hydroxide and the precipitate is removed from the alkali metal sulfate solution.

Abstract: In a first fluidized bed vessel containing an expanded fluidized bed, iron oxide-containing materials are reduced under weakly reducing conditions with solid carbonaceous reducing agents to or to less than the FeO state. In a second fluidized bed vessel containing an expanding fluidized bed the gas-solids suspension discharged from the first fluidized bed vessel is treated with a highly reducing fluidizing gas whereby the material is reduced in part to iron metal. From the gas-solid suspension discharged from the second fluidized bed vessel the carbonized carbonaceous material is separated and is recycled to the first fluidized bed vessel. The exhaust gas from which the carbonized carbonaceous material has been removed is purified and CO.sub.2 is removed therefrom and the exhaust gas is subsequently fed as a fluidizing gas to the second fluidized bed vessel.

Abstract: An aqueous solution which contains ammonium polysulfide is proportionally added to the sour water, which contains cyanide ions, ammonium ions, and sulfide ions. At least part of the cyanide ions contained in the sour water is converted to thiocyanate ions by the ammonium polysulfide. The solution which contains ammonium polysulfide is prepared from an aqueous solution by oxidation in an electrochemical cell. That aqueous solution may consist entirely or in part of sour water.

Abstract: The starting material is a vanadium-containing residue, which contains at least 5 weight percent carbon on an anhydrous basis. The residue is thermally treated in a furnace a) at temperatures from 400.degree. to 700.degree. C. under an oxidizing atmosphere and an O.sub.2 partial pressure of at least 10.sup.-4 bar, measured within the region which is occupied by the residue, and/or b) at temperatures from 500.degree. to 1300.degree. C. under an O.sub.2 partial pressure not in excess of 10.sup.-2 bar, measured within the region which is occupied by the residue. A solids mixture which contains at least 5 weight percent vanadium oxide is withdrawn from the furnace. A multiple-hearth furnace or a rotary kiln or a fluidized bed reactor containing a stationary or circulating fluidized bed may be used as a furnace for the thermal treatment.

Abstract: The waste materials are gasified in a circulating fluidized bed in a gasification reactor, which is supplied with oxygen-containing gas. A gas-solids mixture is withdrawn from the upper region of the gasification reactor and is fed to a separator. Dust-laden gas and separated solids are separately withdrawn from the separator and the separated solids are recycled at least in part to the lower region of the gasification reactor. Temperatures in the range from 700.degree. to 1000.degree. C. are maintained in the gasification reactor. The dust-laden gas which is withdrawn from the separator has a heating value of about 3000 to 6000 kJ/sm.sup.3 and is fed to a combustion chamber and is combusted therein at temperatures from 1200.degree. to 1900.degree. C. Liquid slag is withdrawn from the combustion chamber.

Abstract: Refractory gold ores are roasted at temperatures from 500.degree. to 650.degree. C. in an oxidizing atmosphere in a fluidized bed, which is supplied with a carbonaceous additional fuel. To effect a substantially complete combustion of the additional fuel to form CO.sub.2 and H.sub.2 O, methanol is added as a carbonaceous fuel.

Abstract: In a process for facilitating non-cutting cold working of ferrous materials by application of a phosphate coating, ferrous materials are dipped into a phosphating solution which is free of elements of group VIB of the periodic table which consists of Cr, Mo and W, of nitrogen compounds and preferably also free of nickel and contains5 to 20 g/l zinc1 to 15 g/l magnesium10 to 26 g/l phosphate calculated as P.sub.2 O.sub.51 to 15 g/l fluoroborate calculated as BF.sub.41 to 7 g/l chlorate calculated as ClO.sub.3and in which the weight ratio of Zn:Mg:BF.sub.4 is adjusted to from 1:0.15:0.15 to 1:1:1.