Abstract: A method for concentrating dilute sulfuric acid involves feeding dilute sulfuric acid through at least two electrolytic cells depolarized by sulfur dioxide, and through a cation conductive membrane separating the cathode and anode sides in the electrolytic cell. Also provided is an apparatus for concentrating sulfuric acid, wherein at least a first electrolytic cell is in fluid communication with a second electrolytic cell, and wherein a cation conductive membrane separates the cathode and anode sides in the electrolytic cells.

Abstract: The invention relates to a mixing reactor for mixing a liquid and pulverous solid, clarification the solution that is formed and discharging the clarified solution from the mixing reactor, in the lower section of which a fluidized bed is formed. The invention also relates to a method for mixing a liquid and pulverous solid into each other in a fluidized bed, for clarification the solution that is formed and for discharging the clarified solution from the mixing reactor.

Abstract: A pulp lifter for installation in a rotary grinding mill has a leading edge wall and a trailing edge wall with respect to rotation of the mill. The leading edge wall and the trailing edge wall define a pulp lifter chamber, and a grate allows slurry to pass to a radially outward collecting region of the pulp lifter chamber for removal from the mill by way of a radially inward discharge region of the pulp lifter chamber. In one embodiment, a gate is positioned between the collecting region and the discharge region, the gate being movable between an open position, in which the gate permits solid material to pass from the collecting region to the discharge region, and a closed position, in which the gate prevents return movement of solid material from the discharge region to the collecting region.

Abstract: A process for producing metal oxide from a metal salt includes supplying a first part of the metal salt to a hydrate drier so as to indirectly heat the first part of the metal salt in the hydrate drier using a heat transfer medium from a first stage of a multi-stage indirect cooler so as to dry the first part of the metal salt in the hydrate drier and so as to control a waste gas temperature of the process. A second part of the metal salt is guided as a partial stream past the hydrate drier. The metal salt is preheated in a first preheating stage and precalcined in a second preheating stage. The metal salt and a fluidizing gas having a temperature of 150° C. or less are supplied to a fluidized bed reactor so as to calcine the metal salt to form a metal oxide product. The metal oxide product is cooled in at least one suspension heat exchanger and then in the multi-stage indirect cooler.

Abstract: The invention relates to a method of and equipment for preparing an analysis sample (2) for a continuous on-line analysis. According to the invention, a sample material (5) is taken by means of a sampling arrangement (4) from a material flow (24) that contains solid matter and liquid, whereby the sample material (5) is fed into a chamber (6); a layer of material (10), which contains coarse solid matter, depositing in the lower part of the chamber, and a layer of material (8), which contains liquid and fine solids, being separated from the sample material in the upper part of the chamber, whereby at least part of the material (8), which contains fine solids, is moved to the lower part (9) of the chamber (6), from where the analysis sample (2) that has a higher solids content than the sample material (5) is removed.

Abstract: The invention relates to a turbine-type high-power impeller, to be used for mixing slurry in hydrometallurgical process reactors. The impeller is formed of at least five blades, each of which blades comprises a front edge, trailing edge, root and tip; the roots of the impeller blades are permanently attached by a joint to the hub or axis of the impeller, so that the front edge of the impeller blade is straight, and the trailing edge is chamfered, in which case the blade is narrowed towards the tip, and the blade is provided with two longitudinal folds arranged in parallel with the front edge of the blade.

Abstract: A pulp lifter assembly for a rotary grinding mill includes an outer pulp lifter having walls defining a pulp lifter chamber and an outlet opening for radially inward discharge of slurry from the pulp lifter chamber, and an inner discharger disposed radially inward of the outer pulp lifter and circumferentially offset from the outer pulp lifter. The inner discharger defines a passage for conveying slurry substantially radially inward. A transition discharger is disposed radially between the outer pulp lifter and the inner discharger. The transition discharger has a first wall bounding an interior space and a second wall dividing the interior space into first and second regions. The second wall includes a guide that bounds a channel connecting the outlet opening of the outer pulp lifter to the passage defined by the inner discharger.

Abstract: The invention relates to an apparatus and method for removing molybdenum and other possible impurities from an organic copper-containing extraction solution in connection with the liquid-liquid extraction related to copper recovery. The removal of impurities occurs in one or several removal units built into the organic extraction solution storage tank.

Abstract: A process for producing metal oxide from metal salts includes cleaning a metal salt in a filter. After cleaning, the metal salt is dried in a drying apparatus. Steam is formed in the drying apparatus. The metal salt is preheated in at least one preheating stage. The metal salt is calcined to metal oxide in a fluidized-bed reactor. The metal oxide is cooled. The steam formed in the drying apparatus is recirculated into the filter.

Abstract: A wet gas scrubber is provided for removing at least one of solid and liquid particles from water-saturated gases with a Venturi zone adjustable with respect to the flow cross-section. The wet gas scrubber includes a fixed lower Venturi plate and a vertically adjustable upper Venturi plate disposed above the fixed lower Venturi plate. The Venturi plates are substantially parallel to one another and include corresponding segments configured to engage in each other. A plurality of Venturi channels are disposed between the Venturi plates and configured to guide a mixture of a gas to be cleaned and cleaning liquid droplets injected into a stream of the gas by a nozzle. The segments of the Venturi plates engage in each other while the Venturi channels are kept free.

Abstract: The invention relates to equipment for heating gas in connection with continuous sintering in gas channels placed above a strand, the gas channels comprising at least a wall and at least two gas units, the gas coming from the gas units being in contact with the material on the strand, whereby at least one burner unit is arranged in at least one of the gas channels, being arranged as part of the gas channel, the burner unit comprising at least one separate combustion space arranged on the wall of the gas channel. The invention also relates to a method for heating the gas.

Abstract: The invention relates to a method for purifying impure lithium bicarbonate by means of a cation exchange resin. In addition to solution purification by ion exchange, the treatment stages include the regeneration of impurity metals bound to the resin. Regeneration consists of washing the resin with water, elution with acid solution, washing with water, neutralisation with alkali solution and washing with water. It is characteristic of the method that neutralisation is performed with sodium hydroxide solution.

Abstract: A supply system for providing a suspension smelting furnace with constant and continuous feed is disclosed. The installation of the invention comprises intermediate storage bins for fine-grained feed, a feed rate controller for accurately controlling the feed rate of the fine-grained material, and a pneumatic conveyor for lifting the feed up to the top level of the suspension smelting furnace where the burner of the furnace is adapted. In the installation, the heavy constructions of the storage bins are located close to the ground level and the constructions around and on top of the furnace have been designed essentially lighter than in conventional solutions.

Abstract: The invention relates to a method for removing arsenic as scorodite from solutions that contain iron and arsenic. In accordance with the method, arsenic is first precipitated as ferric arsenate and subsequently processed hydrothermally into crystalline scorodite.

Abstract: The invention relates to a method and arrangement for separating two solutions mixed in dispersion into two solution phases in a liquid-liquid extraction separation cell (1). The arrangement includes a first guide wall (4), which is arranged at a distance from that end wall (15) of the cell (1) that is located on the side of the feed end (2), in order to extend along the whole width of the cell with respect to the vertical direction at an inclined angle (?). The first guide wall includes a bottom edge (5), which is located at a distance (H1 . . . H2) from the cell bottom, so that in between the bottom edge (5) and the cell bottom (3), there is left a clearance gap (6) widening from the center towards the cell sides. The second guide wall (7) is essentially parallel with the first guide wall (4) and placed at a distance (L1) therefrom, so that in between the first guide wall (4) and the second guide wall (7), there is formed an uptake shaft (8) extending diagonally upwards at an inclined angle (?).

Abstract: The subject of the invention is a method for fabricating the discharge end (2) chute arrangement (3) of a liquid-liquid extraction settling tank and the corresponding chute arrangement. The chute arrangement (3) comprises at least one chute member (4, 5; 6), which is made of fibre-reinforced plastic composite. The chute member (4, 5; 6) is manufactured by the filament winding technique essentially making a tubular hollow piece.

Abstract: The invention relates to a method and arrangement for separating two solutions mixed in dispersion into two solution phases in a liquid-liquid extraction separation cell (1). The shut-off element (3, 4, 5) comprises a front panel (8) that extends along the whole width of the cell. The front panel (8) includes a bottom edge (9), which is arranged at a distance (H1, H2, H3) from the cell bottom (7), so that the front panel (8) allows an unobstructed flow of the heavier solution phase directly forwards underneath the bottom edge (9). In the vertical direction, the front panel extends to such a height that it forces the lighter solution phase placed on the heavier solution phase to flow as a thin overflow layer over the top edge (12) of the front panel (8) and forces the dispersion to thicken in front of the front panel.

Abstract: A flange joint for connecting two objects in a fluid connection so that fluid can flow between the objects. The flange joint has a gasket, and the gasket is installed in the flange joint. The flange joint has at least one channel for feeding additional fluid from outside of the flange joint through the gasket into fluid flowing between the two objects.

Abstract: A method of manufacturing a cathode plate (1) that is used in the electrolytic cleaning and recovery of metals, the cathode plate being at least partly manufactured of stainless steel and the surface of the cathode plate being treated in at least one stage, whereby the cathode plate is formed by cutting it from a solid plate-like material (2), whereby, essentially before cutting (4) the cathode plate to shape, at least part of the surface constituting the cathode plate is subjected to a mechanical treatment (3) to improve the adhesion properties of the surface. The invention also relates to the cathode plate.

Abstract: System for the chemical/physical treatment of a fluid in which a distributor valve has been installed for the feed/discharge of fluid to/from various reactors. The distributor valve consists of a plate valve with stationary plate and rotary plate. A cylindrical body provided with a number of axial bores that change into radial bores and emerge in the wall of a stationary housing adjoins the rotary plate and rotates therewith. A number of inlets/outlets located one after the other viewed in the axial direction are provided on the stationary housing. According to the invention the various radial bores in the cylindrical body are provided with a fluid via axial bores, based on a single valve plate.