Abstract: This invention describes a method of reprocessing zinc- and iron oxide-containing residual material. Zinc- and iron oxide-containing dust and/or sludge is granulated with water, granules and carbonaceous material are fed to a circulating fluidized bed system, the gas-solids suspension circulated in the circulating fluidized bed system is fed to a second fluidized bed reactor, the solids discharged from the second fluidized bed reactor are recycled to the reactor of the circulating fluidized bed system, 50 to 75% by volume of the oxygen required to gasify the carbonaceous material are fed as fluidizing gas to the reactor of the circulating fluidized bed system and 25 to 50% by volume of said required oxygen are fed as a fluidizing gas and secondary gas to the second fluidized bed reactor, iron oxide-containing material is discharged from the reactor of the circulating fluidized bed system and zinc-containing material is discharged with the exhaust gas from the circulating fluidized bed system.

Abstract: A waste pickle which has been formed in the surface treatment of rolled stock consisting of steel and contains metal salts and acids and specifically contains nitric and hydrofluoric acids and nickel salts, chromium salts, and iron salts is subjected to an acid dialysis and a membrane electrolysis. To permit a recycling of free acids at a high rate and a recovering of the metals in a form in which they can directly be used in the melting process, the acid dialysis performed for a recovery of the free nitric acid and hydrofluoric acids is succeeded by a membrane electrolysis, in which the metals are recovered from the depleted effluent from the acid dialysis, which effluent has been depleted of free acid, and the enriched effluent from the acid dialysis, which enriched effluent has been enriched with free acids, and the effluent from the membrane electrolysis, which effluent has been depleted of metals, are subjected to an evaporation.

Abstract: Ferritic chromium-molybdenum steels containing26 to 30% chromium1.8 to 3.0% molybdenum3.0 to 4.5% nickelcarbon.ltoreq.0.02%silicon.ltoreq.1.00%manganese.ltoreq.1.00%sulfur.ltoreq.0.015%carbon+nitrogen.ltoreq.0.045%niobium.gtoreq.12.times.%C.ltoreq.1.2%balance iron and impurities which are due to the melting technologyare used as corrosion-resisting material to make structural parts which are resistant to sulfuric acid in a concentration of and above 94% by weight and at a temperature up to the boiling point of the sulfuric acid.

Abstract: For use in making components which are required to have a very high resistance to uniform corrosion and against pitting and crevice corrosion under very highly corrosive conditions encountered in up to date chemical process technology and environmental protection technology, for instance, in flue gas desulfurizing plants for concentrating sulfuric acid, and which are required to be manufactured satisfactorily by conventional hot and cold forming processes an alloy is employed which contains (in % by weight) 22.0 to 24.0 chromium, 15.0 to 16.5 molybdenum, up to 0.3% tungsten, up to 1.5% iron, up to 0.4% vanadium, 0.1 to 0.4% aluminum, 0.001 to 0.04% magnesium and 0.001 to 0.01 calcium, balance nickel and inevitable accompanying elements and impurities.

Abstract: Disclosed in an improvement in a known Ni-Cr-Fe alloy.The alloy of the invention contains 30 to 32% nickel; 26 to 28% chromium; 0.5 to 1.5% copper; 6 to 7% molybdenum; up to 2% manganese; up to 1.0% silicon; up to 0.2% aluminum; up to 0.03% carbon; 0.10 to 0.25% nitrogen; balance iron and usual impurities.The alloy of the invention has increased pitting corrosion potential and critical crevice corrosion and pitting corrosion temperatures whereas the resistance of the alloy to commercially pure phosphoric acid has not been decreased.