Abstract: The present invention relates to a method for removing arsenic from a sulphuric-acid solution by electrolytically precipitating the solution. The employed current density is adjusted by observing the arsenic and copper contents of the solution with a solution analyser, so that operation takes place below the limiting current density peculiar to each system.

Abstract: A process for the recovery of valuable metals from roasted crude-oil sulfur-extraction catalyst waste is disclosed. In this process the value metals can be separated from aluminum in a single stage by treating the waste at elevated temperature and pressure with such an amount of sulfate solution that the waste dissolves and the aluminum simultaneously precipitates as alunite, which is separated from the solution which contains the other value metals. A sulfate solution is preferably added in such an amount that the concentration of sulfuric acid in the solution is 2-30 g/l at the end of the stage.

Abstract: The invention relates to a method and apparatus for the purification of gases, and especially to the purification of industrial flue gases, of solid and/or gaseous impurities. In the method, the gases are scrubbed during a scrubbing stage by spraying into them scrubbing liquid and water, and the drops of liquid are removed from the gases during a drop separation stage. Prior to the scrubbing stage the hot gases are moistened in a pre-moistening stage by spraying into them scrubbing liquid in such a manner that the scrubbing liquid partly vaporizes. The scrubbing liquid is preferably sprayed countercurrently in relation to the gases. The apparatus for the purification of gases consists of a scrubbing unit (3, 4), a drop separation unit (5), devices for circulating the scrubbing liquid countercurrently in relation to the gases, devices for the cooling, regeneration and recycling of the scrubbing liquid, and a pre-moistening unit (2) for the moistening of the gases.

Abstract: A procedure based on suspension smelting has been developed for producing lead bullion from sulphidic concentrates in which the proportion of iron and of slag-forming substances is low. In the procedure oxygen or oxygen-enriched air is used. The slag containing lead oxide that is formed is in equilibrium with the sulphur-containing but refinable lead bullion. The lead oxide content of the slag may be lowered without increasing the sulphur content of the lead bullion by regulating the temperature, the FeO+CaO/SiO.sub.2 ratio and the degree of oxidation. In order that the highest possible amount of the lead contained in the concentrate might be recovered from the settler (3), the quantity of lead compounds in the gas phase is minimized and a hot cyclone is used in the uptake shaft (4) of the smelting furnace.

Abstract: The invention relates to a device for poking a charge fed onto the surface of a melt in an electric arc furnace having a hood and an external cooled casing (2) articulated at one of its ends to the lower section (21) of a horizontal circumferention bend in the wall of the furnace (23) hood (24) which faces the melt, drive cylinders (5) for tilting the casing in different directions about its joint, a spindle ( 1) installed tightly in the cooled casing (2) and being axially reciprocating and rotatable, and drive cylinders (17) for making the spindle (1) to project from said one end of the casing (2) to poke the charge fed onto the melt surface and break any crust on the melt surface or inside the solid charge, when the cooled casing (2) and the spindle (1) inside it are tilted about the joint and rotated.

Abstract: A sealing of a centrifugal pump shaft. When the pump is at rest, the sealing is effected mechanically between surfaces with the aid of loading means, a sealing surface and a packing, and when the pump is in operation, the sealing is effected by means of a hydrodynamically effected fluid ring of the fluid being pumped, formed by means of auxiliary blades which are separate in relation to the impeller.

Abstract: A method and device for facilitating the maintenance and replacing of the contact shoes of the electrodes in an electric-arc furnace, the supporting mantle of the contact shoes consisting of two sections, the lower one of which can be lifted, together with the contact shoes, telescopically over the upper section, whereby the contact shoes rise above the furnace hood.

Abstract: A process for the recovery of valuable metals from metallic alloys having iron as their principal constituent is disclosed in which the metal is leached by means of a sulfuric acid solution having such a concentration that a nearly saturated salt solution is obtained, and after the separation of a possible leach residue the solution is heated close to the boiling point, at which time an acid solution is added in an amount corresponding to the salt which has passed out of the solution, in order to crystallize the salt mixture, the crystallized material is separated from the solution and is decomposed under sulfating conditions, whereafter the metal salts are leached out from the iron oxide by means of water.

Abstract: A combination of a smelting-furnace pouring lip and casting gutter, in which the pouring lip and the casting gutter form a substantially closed system from which a discharge system arranged in connection with the smelting-furnace draws the metal vapors and flue gases through the casting pipe substantially completely.

Abstract: The invention relates to an apparatus for converting matte in two parallelly connected converters (I, II) with essentially equal blowing rates, corresponding the full capacity of the sulphuric acid plant receiving the process gases. Instead of an arrangement where the following converting periods of the two converters (I, II) are carried out in turns, the converting periods of the converters are now partially overlapping in such a fashion that their blowing periods are staggered, so that blowing is always performed in the first converter while the second converter is being charged or poured. By using this method it is possible to achieve very short waiting periods between the converting periods, additional heating is unnecessary and the pair of converters renders a continuous and even gas flow, which has a higher sulphur dioxide content than normally.

Abstract: A method and a hood for mixing a hot furnace gas with a second gas before the furnace gas is discharged from a furnace by directing the hot furnace gases out via a hood which forms an uninterrupted space for gas with the furnace is disclosed in which the second gas is fed along the side walls of the hood substantially countercurrently in relation to the hot gases emerging from the furnace in order to mix the gases with each other into a toroidal vortex, and that the gases are removed from this vortex tangentially.

Abstract: An apparatus for straightening suspension bars removed from cathode plates includes a horizontal press, a vertical press, a vertically movable stop plate, and an ejector in the horizontal press. The horizontal press pushes the suspension bar against the stop plate when the stop plate is in its upper position, and ejects the straightened suspension bar laterally when the stop late is in its lower position.

Abstract: The present invention relates to a process for the separation of gold and silver from complex sulfide ores and concentrates which, in addition to the primary metals, contain constituents having an adverse effect on the separation of the noble metals, by heating the sulfide ore or concentrate at a temperature of 600.degree.-900.degree. C. and a sulfur pressure of 0.2-1 atm in order to bring the complex metal compounds to a suitable form for subsequent alkalic cyanide leaching, and by separating the gold- and silver-bearing cyanide solution from the undissolved residue.

Abstract: A movable apparatus for local electrolytic polishing of metal surfaces is disclosed, the apparatus having an arm, a supported soft surface which is attached to the arm and intended to be brought against the metal surface to be polished, and members for conducting cathodic current to this soft surface and for conducting anodic current to the metal surface to be polished. In the apparatus the supported soft surface is of an absorbent material, which is connected to the electrolyte container in order to cause electrolyte to be absorbed into the absorbent material, as electrolyte is transferred to the polished surface when the apparatus is moved. The electrolyte container may be a trough attached to the arm, the bottom of the trough supporting the absorbent material attached to its lower surface and extending to inside the trough, and the absorbent material may be some acid-resistant wadding.

Abstract: A brickwork construction is disclosed as specifically useful for making the gas distribution chamber of a shaft kiln. In this construction the collapse of the wall into the shaft kiln is prevented by using bricks which are thinner at one end than the other and are laid to make a wall in which there is a straight inner surface to the shaft kiln and an arched side to the gas distribution chamber.

Abstract: A device for blowing gas and a finely-divided solid into a metallurgical melt is disclosed, the device having a blast pipe which has at one end an inlet connected to a gas source and at the opposite end an outlet immersed below the melt surface in order to blow the gas into the melt. A cooling device surrounds the blast pipe, the cooling device having, at that end which is near the blast-pipe inlet, inlets and outlets for the cooling medium, and a mantle of ceramic material which surrounds at least the lower part of the cooling device. In the outlet of the blast pipe there is a Laval nozzle which is at an angle to the blast pipe and extends through the thermally insulating mantle.

Abstract: In the method of the invention starting sheets are stiffened and straightened by pressing or rolling upon the sheet various stiffening patterns projecting from the plane of the sheet, the starting sheet being rolled or pressed from both sides by means of a roller or a press the opposite surfaces of which have the patterns, while the starting sheet is suspended by its lugs.An apparatus is disclosed having conveyors for conveying the starting sheets and a roller or press for embossing stiffening patterns upon the starting sheets, the roller or press having two parallel rollers or press plates, provided with regularly alternating depressions and corresponding protrusions, at least one of the press plates being movable in the lateral direction, the roller or press being mounted below the suspension conveyor for the starting plates in such a manner that a starting sheet suspended by its lugs from the suspension conveyor passes through the roller or press.

Abstract: The average particle size for particles distributed in a slurry is determined by transmitting at least one beam of ultrasonic rays of a certain frequency into the slurry, detecting, by separate detector means, on one hand ultrasonic radiation that passes through the slurry and, on the other hand, ultrasonic radiation scattered in the slurry, said detector means forming first and second signals corresponding to the intensities of the passed-through and the scattered radiation respectively, determining the scattering attenuation factor on the basis of said first and second signals and the total attenuation factor by using the intensity of passed-through radiation obtained with pure water, and determining the particle size with the help of the scattering attenuation factor, whereby the radio of said factor and the total attenuation factor is formed in order to eliminate influence of the slurry density.

Abstract: A method of manufacturing a thin plate or band from copper or a copper alloy is disclosed, the plate or band having flow conduits parallel to its plane, in which a thicker copper plate billet, which also has flow conduits parallel to its plane and the total wall thickness of which, as measured in a direction perpendicular to the plane of the plate, is equal to the thickness of the plate on both sides of the flow conduit, is cold worked to its final material thickness, whereafter the flow conduit flattened during the rolling is opened by means of pressure produced inside it.

Abstract: Starting sheets are straightened and stiffened in electrolytic refining plants by shaping the same predetermined areas of the starting sheet surfaces once or several times during successive shaping stages in such a manner that the elasticity range of the starting sheet material is at least in part exceeded. During each shaping stage depressions or grooves deviating from the plane of the starting sheet surface are produced in the starting sheets by shaping the said same areas of the starting sheet surface alternately from the opposite sides of the starting sheet during the different shaping stages, whereby the alternate shaping of the areas of the starting sheet surfaces from the opposite sides of the starting sheet straightens the starting sheet and causes work-hardening in the material of the starting sheet, and the depressions or grooves deviating from the plane of the starting sheet surface cause a stiffening of the starting sheet.