Abstract: The invention relates to a method for cleaning exhaust gases weak in sulphur dioxide, or sulphur dioxide and hydrogen sulphide. In order to remove the sulphur content of an exhaust gas, the exhaust gas is absorbed into a solution containing sulphide. Thereafter into the solution is added an agent which causes any unstable compounds of sulphur and oxygen, such as thiosulphate and polythionates, which are formed in the scrubbing solution, to decompose into elemental sulphur and sulphate in the autoclave whereinto the scrubbing solution is fed. The pH of the solution emerging from the autoclave is adjusted to stay within the range 2.0-2.9.

Abstract: The purpose of the process is to remove and to recover metals from their aqueous solution by the extraction process. As extractant is used monoesters of phosphonic acid wherein the alkyl group is a phenyl-vinyl group or straight-chained and the ester group is straight-chained. The particular advantage of the process is that the metals can be removed from aqueous solutions to be treated without neutralization of the acid quantity produced during extraction, and this acid solution produced can be circulated e.g. to the stage before the extraction. The process can be used to the removing of metals from the industrial waste waters.

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: The present invention relates to a method for utilizing slag from metal production, particularly the silicate slag with a high iron oxide content resulting from copper or nickel proceses, in the production of heat-resistant, fire-resistant and/or alkali-resistant fibre material. According to the invention, the temperature dependence of the slag viscosity is changed by means of alloying the slag so that the relative proportion of the acidic components contained in the slag is increased.

Abstract: The invention relates to an apparatus for separating materials by making use of the difference in the specific gravities, when the material under separation is made to flow in countercurrent with respect to the flowing medium. The separating apparatus of the invention is advantageously composed of at least two flow pipes (2) with essentially equal diameters, and each of these is provided with a connected side flow pipe (6) by aid of which the material under separation can be divided into at least three different fractions.

Abstract: The invention relates to a method and apparatus for stripping a thin, sheet-like layer of electrolytically accumulated metal precipitate (6) from its supporting structures (1) by means of a peeling blade (4) driven towards the upper edge of the precipitate layer (6). For the stripping operation, the supporting structure (1) is first attached to the stripping station by aid of gripping members (2, 3), the frame whereof advantageously provides a housing in common with the peeling blades (4). Moreover, the measuring and control members (7, 8) which are advantageously located in the common housing, are used in determining the surface profile of the supporting structure (1), and the obtained profile is made use of while choosing the orientation of the peeling blade (4).

Abstract: A spiral heat exchanger composed of two separate pipe systems, wherein each heat exchange medium runs in its own pipe system. The heat-emitting and the heat-absorbing pipe sytems are arranged in a tight, intermeshing fashion, in order to improve the heat exchange between the separate spirals, these are interconnected by employing a medium metal. The medium metal is applied by soldering, by dipping the heat exchanger into molten metal or by casting the molten metal on top of the exchanger.

Abstract: The invention is related to a method for dispersing two phases in an extraction process so that each extraction step includes several mixing stages, and at each mixing stage the mixing is carried out by means of a vertical circulation and advantageously at least one mixing stage is provided with an intensified vertical circulation. According to the invention, the dispersing apparatus of one extraction step in an extraction process is formed of several mixers provided with circulation cylinders (11). Advantageously at least one of the mixers is provided with a dispersing pump (16).

Abstract: A stripping analysis method comprises a preelectrolysis step during which liquid to be analyzed is introduced into a measurement cell at a pulsating rate, a working electrode is vibrated at an ultrasonic frequency, and the voltage potential between the working electrode and a reference electrode is adjusted to a level which allows the substances to be determined to be deposited on the working electrode. After the preelectrolysis step is a stripping step during which the voltage potential between the working electrode and the reference electrode is scanned through the potential range where the substances to be determined are dissolved back to the liquid and current is measured while the liquid in the measurement cell remains essentially undisturbed. The method also comprises an elimination step during which the voltage potential between the working electrode and the reference electrode is adjusted to a level at which the working electrode is regenerated.

Abstract: A method for treating hazardous waste contained in barrels (1), in which method the barrels (1) are cut up and/or crushed in a shearing device (9) so that the created waste mass can be pumped into a kiln furnace (4) by means of a paste pump.

Abstract: The invention relates to a method and apparatus for changing the casting table, complete with the mold and the starter head in the casting machine, particularly a semi-continuous casting machine. In order to carry out the exchange, the casting table (7) complete with the mold (10) and the starter head (5) are first supported against each other, whereafter the casting table (7) and the starter head (5) are together shifted in between the casting position and the changing position.

Abstract: The invention relates to a method for heating a gas phase stabilizer (5) installed within a gas-filled proportional counter (1) in order to activate the stabilizer (5). According to the invention, the heat is conducted into the proportional counter (1) along a thermal inlet (3), which is in thermal exchange contact with the stabilizer (5). The thermal inlet (3) employed in forming the gas filling can advantageously be employed for heating the stabilizer up to the activating temperature.

Abstract: The invention relates to an apparatus for measuring the length of the electrodes in an electric furnace, wherein by aid of the apparatus of the invention, into the furnace there is inserted a measuring rod which feels the end of the electrode in the furnace, and thus the distance of the electrode located in the material bed is detected with respect to the furnace bottom.

Abstract: The invention is related to a method for measuring the quantity of a dried product, particularly that of a concentrate dried in a pressure filter. The method comprises the following stages: inserting (1) the product to be dried in the drying apparatus, carrying out the drying (1,2,3) and discharging (5) the dried product from the drying apparatus. In order to define the exact quantity of the dried product, the whole drying apparatus is weighed (4) both before discharging the dried product and immediately thereafter. The weighing results are processed in a microprocessor. By means of history recordings of the weighing results, the drying process itself can also be optimized.

Abstract: The invention relates to a method for dispersing the two liquid phases of a solvent extraction process well together, for controlling the desired type of dispersion and for raising the created dispersion to a level essentially higher than the liquid surface in the mixing tank. In the apparatus of the invention, to the circulation cylinder (6) of the mixer there is connected the heavy phase return conduit (27) and the light phase return conduit (29) entering from the settler of the same extraction step. In the top part of the mixer, coaxially with the turbine pump (9), there is installed the dispersion pump (12) where the dispersion rises to above the liquid surface (8) of the mixer through 2-24 rising pipes (15). The top ends of the rising pipes (15) are connected to the circular pipe (18), wherefrom the dispersion flow is conducted to the next stage through the collecting trough (22).

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: A method for the continuous recovery of non-iron metals from a molten metallurgical slag containing lead, copper or nickel by continuously reducing the layer with carbon dust. The metal layer produced at the furnace bottom is maintained sufficiently thin so that it is between 0 and 20 mm thick. Injection of carbon dust into the metal layer is avoided.

Abstract: An extraction unit of the type having successively in the flow direction of the liquid, a mixer, a pre-settler and a settler, the pre-settler and the settler being separated from each other by several successive perforated partition walls, the perforations of each partition wall being laterally unaligned with the perforations of the following partition wall, the lower section of the mixer having inlets for the heavy phase and the light phase and a mechanical stirrer for mixing the heavy phase and the light phase to form a dispersion, and the upper section having at least one opening for directing the dispersion from the mixer to the pre-settler, the upper section of the settler having members for removing the separated light phase as an overflow from the settler, the lower section of which has an opening for the removal of the separated heavy phase from the settler as a controlled flow, and between the settler and the mixer there are pipes for returning part of the separated heavy and light phase from the set

Abstract: The object of the present invention is to protect the driver unit (1) of an immersible aerator and/or mixer apparatus against the surrounding liquid. The driver unit (1) is covered with a compact protective casing (5), to the bottom part whereof the gas to be lead into the mixer (14) is conducted through the gas supply pipe (2). At the junction of the gas supply pipe (2), inside the protective casing (5), there is located a gas supply channel (6) which is open at both ends, and this gas supply channel (6) conducts the gas to flow mainly upwards, to the top part of the driver unit. At its bottom, the protective casing (5) is attached to the base disc (7), and the gas flows through the holes (10) provided in the base disc (7) into the channel formed by the gas control cone (11) and the inner cone (12), and therefrom into the liquid either via the partly hollow secondary axis (13) of the mixer or via a separate gas pipe.

Abstract: The present invention relates to a method for treating iron-bearing slags containing precious metals, particularly slags created in copper and nickel smelting processes, by reducing the slag so that by means of adding a possible sulphidizing agent, the composition of the molten slag is regulated in solidified state to fall within the area where the metallicized, iron-bearing molten copper sulphide is in balance with the metallic copper and the iron-base metal alloy. By means of controlled cooling, the precious metals contained in this molten sulphide having an advantageous liquidus temperature are concentrated into the iron-base metal phase, whereafter the phase containing the precious metals can be separated by means of magnetic separation. After the magnetic separation, a selective hydrometallurgic treatment is carried out in order to recover the precious metals.