Abstract: A process for the removal of harmful impurities, particularly arsenic, antimony, bismuth and lead, from metallurgical sulphide melts, in which the sulphide melt is sulphurated before conversion, during the slag-blowing stage or after it before the blister-blowing stage, and the melt is refined with nitrogen or other inert gas during sulphuration and possibly after it, so that the amount of sulphur supplied to the sulphide melt is at least 10% in excess of the stoichiometric sulphur amount as calculated from the sulphur requirement of the principal components of the melt.

Abstract: An iron-free chromium(III) compound is precipitated at an elevated temperature and pressure from an acidic aqueous solution which contains iron and chromium. In order to prevent coprecipitation of iron, an additive is added to the precipitation stage in an amount sufficient to provide in the precipitation conditions at least 2 g/l of bivalent chromium in the solution.

Abstract: The invention relates to a method and apparatus for forming a directioned and controlled suspension spray of a pulverous material and reaction gas in such a manner that the reaction gas directed along one, often horizontally approaching channel is divided into three or more partial channels by means of mainly radial partition walls. When necessary, guide blades or a venturi-like mixing and guide member is used. The reaction gas is deflected so as to have the desired direction, often vertically downwards so as to be parallel to the central axis of the reaction chamber, such as a flash-smelting furnace. The thus formed partial flows of reaction gas are often caused, furthermore, to discharge, divided further into two or more parts, as an annular flow encircling on each side the member for feeding pulverous material, situated in the middle of the flow, into the reaction chamber.

Abstract: Lead in separated from a sulfidic concentrate by feeding a finely-divided concentrate, a silicate-high slagging agent, and air or oxygen-enriched air into the upper section of a suspension reaction shaft of a flash-smelting furnace in order to form a suspension and to oxidize the lead to lead oxide, by removing the gases via a riser pipe of the furnace and by discharging melt from a lower furnace of the flash-smelting furnace for further treatment. The slagging agent is fed at such a rate that substantially all of the melt is of the slag type and that all of the melt withdrawn from the lower furnace is directed to a reduction stage in order to reduce the lead silicate and to separate it as raw lead.The transversal cross section of the lower furnace is preferably substantially circular.

Abstract: Lead is recovered from a lead-bearing sulfidic concentrate by heating the concentrate in such a manner that lead and its compounds pass into the gas phase. The oxygen pressure in the gas phase is adjusted by oxidation or reduction in order to cause the compounds of lead to react with each other to form lead, and the gas phase is cooled in order to condense the metallic lead out from the gas.

Abstract: A process is disclosed for the recovery of lead, silver and gold from the iron-bearing residue of an electrolytic zinc process by froth-flotating a slurry of the iron-bearing residue in the presence of a sulfidic collector agent in order to froth-flotate the sulfides and to separate them from the iron-bearing residue. The iron-bearing residue is sulfidized selectively in order to convert the lead, silver and possibly gold substantially quantitatively to sulfides before the iron-bearing residue is froth-flotated.

Abstract: Zinc, copper and cadmium are recovered from their ferrites by subjecting the ferrites to a sulfuric acid bearing solution in the presence of potassium, sodium or ammonium ions under atmospheric conditions at 80.degree.-105.degree. C. to precipitate the iron present in the ferrites as jarosite, separating at least a portion of the jarosite-bearing solid material from the solution before recycling the solution to a neutral leach, from which a copper and cadmium bearing solution is recovered and to which acid and calcine are also fed, feeding the solid obtained from the neutral leach to the said ferrite treatment stage classifying the solid obtained from the neutral leach into a finer and coarser fraction, feeding the finer fraction to the ferrite treatment stage, comminuting the coarser fraction by grinding, leaching or milling and recycling the comminuted fraction to the process.

Abstract: A process for the selective froth-flotation of sulfidic, oxidic and salt-type minerals, whereby an ore is first wet ground to the flotation fineness to obtain a slurry and then the obtained slurry is prepared and froth-flotated. In addition to the collector agent a polysaccharide, lignosulfonate, quargum and/or a surface active additional chemical is used which prevents the collector agent from adhering to the silicate surfaces and passivates active silicate mineral surfaces, or weakens the hydrophobia of minerals to which the collector agent has already adhered. The collector agent and the additional chemical may be added as early as the wet-grinding stage.

Abstract: The impure jarosite residue of an electrolytic zinc process is leached in a sulfuric-acid-bearing solution in order to produce a leach residue which contains lead, silver and gold and a ferrisulfate-bearing solution and to separate them from each other, whereafter the leach residue is sulfidized and froth-flotated in order to recover a combined concentrate which contains lead, silver and gold, and the ferrisulfate-bearing solution is fed to a ferritic treatment stage, in which ferrisulfate and ferrites react in the presence of ions of alkali and ammonium at 80.degree.-105.degree. C. and form pure jarosite and zinc sulfate.

Abstract: A hydrometallurgical process for the treatment of a raw material which contains oxides and ferrites of zinc, copper and cadmium is disclosed, wherein the raw material is neutral leached by means of a sulfuric-acid-bearing solution to leach the oxides without substantial dissolving of the ferrites, a ferrite-bearing residue is separated, and a sulfuric-acid-bearing or ferrisulfate-bearing solution is mixed with the residue in order to leach the ferrite and to precipitate the iron in the form of jarosite in the presence of alkali or ammonium ions under atmospheric conditions at 80.degree.-105.degree. C., and the solid phase is separated from the solution.

Abstract: A process for the treatment of a raw material which contains oxides and ferrites of zinc, copper and cadmium is disclosed, in which the raw material is neutral leached with a sulfuric-acid-bearing solution in order to leach the oxide without substantial dissolving of ferrite, the ferrite-bearing residue is separated, and a sulfuric-acid-bearing or ferrisulfate-bearing solution is mixed with the residue in order to leach the ferrite and to precipitate the iron as jarosite in the presence of alkali ions or ammonium ions under atmospheric conditions at 80.degree.-105.degree. C., the sulfuric-acid-bearing or ferrisulfate-bearing solution being added to the ferrite-bearing residue in such an amount that approximately 50-60% of the ferrite dissolves and its iron precipitates as jarosite, the solid phase is dried and heated to so high a temperature that the zinc of the solid phase is converted to zinc sulfate and its iron to hematite according to the following reaction:(8) 3ZnFe.sub.2 O.sub.4(s) +2A[Fe.sub.3 (SO.

Abstract: A copper wire for intrauterine contraceptive devices is disclosed as having a core wire of a flexible tough metal nobler than copper and a copper coating fixed on the core wire by means of a thin diffusion layer.

Abstract: A method for forming a turbulent suspension from a pulverous material and reaction gas by causing the pulverous material to flow downwards as an annular flow into the reaction chamber and by directing the reaction gas downwards inside the annular flow of the pulverous material, in which the suspension is produced by bringing the reaction gas into a high-force rotary motion and by then causing it, throttled, to discharge into the reaction chamber so that in the reaction chamber it meets on its outside a substantially vertically downward annular flow of the pulverous material, this flow being formed by utilizing the kinetic energy of the falling pulverous material on a convergent conical glide surface.

Abstract: A method is described for sequential replacement of the lining in a rotating mill according to wear of the lining. Generally, such a lining consists of adjacent zones parallel to the rotational axis of the mill, the height of these zones varying periodically in the peripheral direction of the mill. According to the invention rubber beams of equal width are used, and for the replacement operation completely fresh beams of only one height are employed, this height representing the highest one of only a few preselected categories of beams. Upon removal of worn beams, these are reassorted according to the selected categories and those beams worn-out and unfit for even the lowest category are discarded. Thus, the reassorted beams not rejected can be reused properly positioned so as to maintain a suitable variation of the beam height in the peripheral direction of the mill, and only one height of fresh beams need to be held in stock.

Abstract: A finely-ground nickel-copper matte is leached using an acid at a minimum temperature of approx. 80.degree. C. and under oxidizing conditions in order to produce a nickel sulfate solution and a nickel-cooper sulfide residue, which is separated from the solution and thereafter the nickel-copper sulfide residue is leached using acid in an autoclave at a minimum temperature of 110.degree. C. and under oxidizing conditions in order to produce an additional quantity of nickel sulfate solution and a copper sulfide precipitate.

Abstract: A process for the separate recovery of phosphate and carbonate minerals from finely-divided phosphate-carbonate-silicate ores or concentrates with a carbonate to phosphate ratio of over 1 is disclosed, in which an anionic collector agent is added to an aqueous slurry of these ores and concentrates, the slurry is then exposed to froth-flotation in order to separate a silicate-bearing residue from phosphate-carbonate concentrate, thereafter(a) the combined phosphate-carbonate concentrate is either treated with a base in order to remove the collector-agent coatings from the surfaces of the mineral particles, whereafter the combined concentrate is froth-flotated with a cationic collector agent using a depressing agent for carbonate in order to recover the phosphate concentrate and the carbonate concentrate separately, or(b) the aqueous slurry to which the anionic collector agent has been added and which has been froth-flotated is treated with sulfur dioxide or carbon dioxide in order to inactivate the collector-a

Abstract: Coke or activated carbon is produced from a moist organic substance, for example from a residue from the production of furfural. Initially the moist organic substance is introduced together with hot flue gases into a drying zone of a cylinder furnace and the organic substance is mixed with the hot gases and dried according to the co-current principle. Subsequent thereto the dried substance and the gases are directed into a coking zone of the same furnace, an oxygen-bearing gas also being introduced into said coking zone and the volatile constituents of the organic substance being reduction burned according to the co-current principle so as to produce a coked product. When coke is to be produced, said coked product is withdrawn together with gases from the trailing end of the furnace and the gases are separated therefrom.

Abstract: A molten metal matte low in iron is oxidized by blasting oxygen or air into the metal layer to produce raw metal.

Abstract: A pipe spiral bundle for a heat exchanger is produced by using pre-fabricated pipe spirals of the same shape, each pipe spirals having pipe loops essentially in one plane and at distances inside each other, such spirals being arranged concentrically and directly on top of each other and then tightly attached to each other so as to form a continuous spiral-shaped contact line between adjacent spirals, and a mutual branch pipe being connected to one end of each pipe spiral and a mutual collector pipe being connected to the opposite end of each pipe spiral. The pipe spirals may be heat welded to each other or connected to each other by mechanical binding members, such as metal bands.

Abstract: Sulfidizing pre-treatment of slag from pyrometallurgical processes in order to facilitate its further treatment, by stacking solid sulfur-bearing reductant and molten slag in alternate layers, the temperature of the molten slag being so low that crystals are formed upon the addition of the reductant, or soon after the addition of the reductant, but at the same time so high that it suffices for melting the reductant between the slag layers; and by allowing the slag to cool.