Abstract: The invention relates to a method for utilizing zinciferous waste from metal smelters, such as steel smelters, so that the transmission of fluorides to the highly zinciferous secondary dusts is prevented during the treatment of the gas obtained from the waste smelting furnace. Fluorides are extremely harmful for the zinc process, and therefore it is important to prevent them from entering the process. By adjusting, according to the invention, the temperature and composition of the exhaust gases created in the smelting treatment of zinciferous dusts and other waste, the fluorides and the highly zinciferous fraction are obtained in different end products. Other valuable metals are recovered from the metal layer created on the bottom of the furnace.

Abstract: The present invention relates to a method for preparing iron silicate slags, by means of mixing with ferroalloy slag, to a molten slag which can be defibrated into fire-resistant and chemically resistant fibers. The advantageous composition for the molten slag is 15-25% Fe, 45-69%, SiO.sub.2 0-5% CaO, 4-10% MgO, 5-15% Al.sub.2 O.sub.3 and 0.5-3% Cr (percentages by weight).

Abstract: The invention relates to a method for utilizing slag from ferroalloy production in manufacturing heat-resistant, fire-resistant and/or alkali-resistant fiber materials, when the original slag is based on aluminum oxide and silicon oxide. According to the invention, aluminum oxide and/or silicon oxide is added into the molten slag in order to change the slag viscosity and to adjust the defibration temperature of the slag.

Abstract: A process for the exploitation of low-grade oxidic and iron-bearing complex ores or concentrates, whereby the initial materials are reduced in a rotary kiln at a temperature of 1000.degree.-1500.degree. C. in such a manner that the products are a magnetic fraction primarily consisting of iron, and a non-magnetic oxide fraction, the materials present in this fraction being further exploitable by conventional methods.

Abstract: The invention relates to a method for manufacturing heat-resistant and/or fire-resistant fibre materials, when the employed initial material is molten slag from metal processes. According to the invention, the slag holding furnace (5) is used for achieving an essentially even and continuous molten flow from the slag smelting furnace (3) into the mineral wool furnace (6). The invention also relates to an apparatus for realizing the method, wherein the holding furnace (5) is provided with at least one control device (12) which shifts the furnace (5) between the different filling positions in order to ensure an even and continuous flow of molten material.

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: 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 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 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: 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: 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: 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: 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.

Abstract: A process for coating an electrically nonconductive material with a metal by attaching a less noble metal or a compound thereof, in pulverous form, to the surface of the electrically nonconductive material and spraying a solution of the nobler metal on the surface thus coated in order to cause the nobler metal to adhere to the surface.

Abstract: A ferrochromium slag for use as a refractory material having good resistance to mechanical compression and wear is disclosed to contain less than 25% by weight of MgO.

Abstract: A method and an apparatus for refining a melt by means of a pulverous solid material and a carrier gas, in which the pulverous solid material and gas are injected into a reactor while melt is poured into the reactor, the kinetic energy of the melt created by falling being utilized for mixing the pulverous reagent and the gas with the melt, and the agitation of the melt surface being attenuated by causing the flow of the injected pulverous reagent and gas and the flow of the melt being poured to impinge against each other from opposite directions in the reactor.