Abstract: The invention relates to a method and an apparatus for cooling a material to be removed from the grate of a fluidized bed furnace. Material at a high temperature is passed from the grate of the fluidized bed furnace into a fluidized bed cooler in charges of a given size by measuring the quantity of the material accumulating in the fluidized bed cooler. When the quantity of the material in the cooler has reached a predetermined limit value, the supply of material into the fluidized bed cooler is prevented. The charge is cooled in the fluidized bed cooler by fluidization air and via heat transfer into a cooling liquid circulation system and the temperature of the charge is measured. The charge is removed when the temperature of the charge has fallen to a predetermined limit value. The second end (5) of a supply conduit (3) is provided with a supply valve (15) actuated by a power means (16). A discharge conduit (14) is provided with a discharge valve (17) actuated by a second power means (18).

Abstract: The invention relates to a method for processing a metal-bearing sludge in conjunction with a metal separation process. According to the invention, the sludge (13) produced in the metal separation is classified based on a predetermined property of the sludge into a better (15) and a worse (17) substance fraction, as the process is concerned, and the worse substance fraction (17) is removed from the process and the better substance fraction (15) is returned to the process.

Abstract: The invention relates to a method and apparatus for controlling a continuous metal removal in conjunction with a zinc preparation process, in which the metal removal is performed in one or more reactors (11a-c), in conjunction with the reactor, the redox potential (16a-c) and the acidity and/or basicity are measured, and based on the measurement results, the process variables (17a-c) of the metal removal are adjusted towards the desired direction. According to the invention, the redox potential measurements (16a-c) are performed from the sludge produced in the reactor in conjunction with the outlet pipe of the reactor outside the reactor, and the measuring instrument (16a-c) is purified at predetermined intervals.

Abstract: A direct reduction process for a metalliferous material includes supplying a solid carbonaceous material and an oxygen-containing gas into a fluidized bed in a first vessel and generating heat by reactions between the oxygen-containing gas and the solid carbonaceous material and any other oxidizable solids and gases in the fluidized bed and discharging a hot off-gas stream containing entrained solids. The process also includes supplying the metalliferous material to a fluidized bed in a second vessel and supplying the hot off-gas stream containing entrained solids from the first vessel to the fluidized bed in the second vessel and partially reducing the metalliferous feed material in the solid state in the fluidized bed and discharging a product stream of partially reduced metalliferous material and an off-gas stream containing entrained solids.

Abstract: The invention relates to a stator for a flotation cell to be used in the flotation of slurry-like material, such as ore and concentrate containing valuable minerals, said stator including flow regulators installed at regular distances from each other. The stator flow regulators are installed to be movable, so that the flow regulators can be adjusted at a desired distance from the rotor rotation axis.

Abstract: The invention relates to a hydrometallurgical metal for separating the precious metals and impurities of anode sludge obtained from copper electrolysis. According to the method, anode sludge copper is separated in atmospheric leaching; calcinated in two steps for separating selenium and for sulfatizing silver; the sulfatized silver is separated by leaching into a neutral aqueous solution, from which it can be separated by reduction or by extraction.

Abstract: This invention relates to a method for removing mercury from dilute sulphuric acid. According to the method sulphuric acid solution is scrubbed with an aqueous solution containing thiosulphate, which precipitates the mercury present in the sulphuric acid solution either as mercury sulphide or, in a chlorine-containing environment, as a mercury sulphide-mercury chloride double salt. The quantity of thiosulphate to be fed is adjusted so that it precipitates the mercury in the sulphuric acid solution, but still does not form elemental sulphur.

Abstract: The invention relates to a device to be used in connection with thickening and clarifying apparatuses for shear-thinning of solids containing material, such as slurry, which device contains one conduit for feeding material to be shear-thinnned and another conduit for discharging back the shear-thinned material between a thickening apparatus and the shear-thinning apparatus. The conduit (3,23) for feeding material to be shear-thinned and another conduit (4,24) for discharging back the shear-thinned material are positioned essentially concentrically to each other at least in the ends connected to the thickening apparatus (2,22).

Abstract: Device for carrying out a chemical or physical treatment, comprising a frame on which a turntable is arranged rotatably. The reaction vessels are arranged on the turntable, and a different connection between the feed/discharge lines, which are fixedly connected to the frame, and the reaction vessels is constantly provided via a valve assembly. The valve assembly comprises two disks, each provided with ports which are positioned opposite one another in constantly changing positions. In order to minimize the non-operational time, an indexing movement is carried out using the turntable. In the case of relatively large installations, to prevent associated forces from affecting the movement of the valve assembly, it is proposed that the valve assembly be fitted directly on the turntable and that the turntable be driven directly by the motor.

Abstract: The invention relates to a method for reversing the dispersion formed in the mixing section of liquid-liquid extraction and kept condensed in the separation section and the separated solutions from the rear end of the separation section to flow back towards the feed end of the separation section as two separate streams. The invention also refers to the extraction equipment for implementing the reversed flow.

Abstract: A process for reclaiming spent selenium filter mass containing an inert material, following take-up of mercury by a substance which contains selenium and is present in the filter mass. The spent mass is treated with a hydrogen peroxide solution for leaching out of the selenium content in essentially all unspent active substance present in the mass to form selenious acid. The resulting selenious acid is separated and isolated for use. The mass freed of the solution is treated with aqua regia for dissolving essentially all of the mercury selenide present in the mass. The aqua regia solution with its content of mercury and selenium are separated from the mass and isolated. Suitably, after it has been washed and dried, the mass freed of the aqua regia solution, which now only contains inert carrier material, and also the previously isolated selenious acid, are transferred to production of new selenium filter mass.

Abstract: The invention relates to a method for processing concentrates, particularly concentrates produced from copper sulfide-based ores. According to the method, the concentrate (4) to be processed, obtained from ore concentration, is divided into two parts, to a concentrate (7) mainly containing poorly soluble components, and to a concentrate (8) mainly containing well soluble components. The concentrate (8) containing well soluble components is conducted to a leaching step (9), and the solution (13) obtained from said leaching step is conducted to at least one conversion step (11, 16), and to the conversion step (11) that is located first in the flowing direction, there is fed the concentrate (7) containing poorly soluble components.

Abstract: The invention relates to a method for the improvement of current efficiency in electrolysis. According to the method, a theoretical cell voltage is first calculated, which is compared with the measured voltage. The cumulative difference between the theoretical and measured cell voltage is monitored constantly and when this difference is proportioned to the current efficiency, information on the status of the process can be obtained continually. A decrease in current efficiency is a clear indicator of short circuits between the electrodes, and by means of the method according to the invention, it is possible to concentrate the short circuit removal work onto the correct cell groups, from the point of view of the current efficiency of the electrolysis.

Abstract: The invention relates to a method for the hydrolytic precipitation of iron as jarosite from a sulphate-containing solution in connection with zinc recovery from zinc calcine. The recovey contains neutral leach, ferrite leach, zinc electrolysis and iron precipitation stages. The ferrite included in the calcine is leached with return acid of the electrolysis after which the iron present in ferrous form is neutralized and routed to an iron precipitation stage, where the iron is oxidised to the trivalent form using an oxygen-containing gas. Also present in the precipitation stage arc Na, K or NH4 ions and jarosite nuclei.

Abstract: The invention relates to a method for smelting sulfidic copper concentrates, in which method copper sulfide bearing material is smelted in a smelting furnace (1) for creating blister copper and slag. According to the method, at least part (3) of the feed of the smelting furnace (1) is copper sulfide bearing (3) material obtained by means of sulfide bearing material (2) that is fed into the hydrometallurgic further processing (12,19) of slag (11) created in the smelting process.

Abstract: The invention relates to a mixing apparatus and a method for mixing gas in a closed mixing reactor, which uses gas as a process chemical with a high efficiency and where the content of pulverous solids in the solution is great. The aim is to obtain a flow in the reactor which sucks gas from above the surface of the liquid using rotating mixing devices in the centre of the reactor, and to mix said gas throughout the reactor capacity. The mixing apparatus of the invention comprises at least two mixers located at different heights, and on the same shaft. The upper mixer is equipped with a central plate attached to the shaft, with essentially vertical inner blades rising upwards and downwards and outer vanes directed outwards from the central plate, which are inclined from the horizontal. The lower mixer is equipped with a central plate attached to the shaft with vertical blades located on the outer edge.

Abstract: The present invention relates to method, which helps to reduce and remove the build-up forming on the grate of a fluidized-bed furnace in the roasting of fine-grained material such as concentrate. The concentrate is fed into the roaster from the wall of the furnace, and oxygen-containing gas is fed via gas nozzles under the grate in the bottom of the furnace in order to fluidize the concentrate and oxidize it during fluidization. Below the concentrate feed point, or feed grate, the oxygen content of the gas to be fed is raised compared with the oxygen content of the gas fed elsewhere.

Abstract: The invention relates to the improvement in the quality of cathodes produced in an electrolysis process. The surface of a cathode lifted from the cell during the cathode cycle is photographed and the physical quality of the cathode can be investigated in real time by means of equipment based on image-analysis. On the basis of the quality of the cathode surface, it is possible to monitor and control the electrolysis conditions in order to improve the quality of the cathode. The method is extremely suitable for the electrolytic purification of copper.

Abstract: The present invention relates to a froth flotation mechanism located in a flotation cell, comprising a directional element suspended from the lower end of a hollow shaft extending to the lower section of the cell and vertical vanes attached to said directional element, which extend above and below the directional element and horizontally beyond the directional element. The substantially horizontal circular plate of the directional element is symmetrically attached around the shaft at its centre and the outer edge of the central plate is bent downwards to form the lap of the guiding part. The gas spreading plate is located on the inner side of the lap. The flotation cell is comprised of a cylindrical lower section, a middle section located above it in the form of a truncated cone widening upwards, and a cylindrical upper section attached to the top of it.

Abstract: The invention relates to a method for increasing the capacity of a waste-heat boiler (1) processing gases obtained from a metallurgic smelting furnace, such as a flash smelting furnace, and for reducing dust accretions, where liquid is added into the waste-heat boiler (1) of the smelting furnace. The invention also relates to an apparatus for increasing the capacity of a waste-heat boiler (1) processing gases obtained from a metallurgic smelting furnace, such as a flash smelting furnace, and for reducing dust accretions, in which case the waste-heat boiler is provided with at least one nozzle (2) for adding liquid.