Abstract: The invention provides a process for the production of a granule of a coated oxidizing compound which granule has good delayed release properties, said process comprising a) providing cores of an oxidizing compound produced by fluidized bed spray granulation, b) spraying on the oxidizing compound cores an aqueous solution of metal sili-cate in a fluidized bed, said aqueous solution comprising at least 15% by weight metal silicate, and c) drying to form a metal silicate coating layer on the oxidizing compound core, provided that the amount of metal silicate coating layer is at least 8%, preferably at least 10% by weight based on the total weight of the granule. The invention also provides such granule and well treatment fluids including such granule, and processes for use.

Abstract: The present invention relates to a use of a two-way spray nozzle (1) with protective gas for manufacturing granular sodium percarbonate, said nozzle comprising a central tube (2) having an outlet for an aqueous hydrogen peroxide solution, an inner jacket tube (3) arranged coaxially around the central tube, and having an outlet for aqueous sodium carbonate solution, an outer jacket tube (4) arranged coaxially around the central tube and inner jacket tube, and having an outlet for a protective gas, a threaded ring slot (5) arranged around the central tube at a distance from the outlet of the central tube, wherein the threads of the ring slot are arranged at an angle ? with respect of the direction of the longitudinal axis (12) of the central tube, and in which said protective gas is used at a pressure of less than 0.7 bar. The present invention also relates to a method for manufacturing granular sodium percarbonate.

Abstract: The present invention relates to a process for the production of polyaluminium salts, preferably polyaluminium sulphate and polyaluminium chloride, and derivatives thereof, from aluminium containing raw materials and acids, wherein microwaves are used for partial heating of the reaction mixture. The present invention also relates to a system for the production of polyaluminium salts and derivatives thereof.

Abstract: A method of treating, in wastewater purification, sludge containing organic matter, divalent iron and phosphorus, in which the sludge that is treated is made to contain dissolved iron and phosphorus at a molar ratio Fe:P of above 1:1, the sludge is treated at 0–100° C. with an acid at a pH of 1–5 for dissolution of divalent iron and phosphorus from the sludge, the sludge is supplied with an oxidizer selected from hydrogen peroxide and percompounds, wherein divalent iron is oxidized by Fenton's reaction to trivalent iron, and (i) trivalent iron is precipitated as trivalent iron phosphate (ii) free radicals with a deodorization and sanitation effect are formed by Fenton's reaction, the sludge is then dewatered at a pH of at most 7, and the aqueous solution obtained in dewatering is recirculated to the wastewater purification.

Abstract: A method of treating residual acid from production of chlorine dioxide is described. The method is characterized in that a compound containing iron is added to the residual acid to react therewith and form a product, which contains iron in trivalent form. As iron compound preferably ferrous sulphate is added, which under oxidation reacts with the residual acid to form ferric salt. Preferably sodium chlorate, sodium hypochlorite, hydrogen peroxide or an oxygen-containing gas is added as oxidant.

Abstract: A method in bleaching of pulp is described, in which the pulp is subjected to a peroxide bleaching step, whereupon the pulp is washed and the washing liquid from the washing is separated from the pulp in the form of a filtrate. The method is characterised in that the filtrate is treated with an aluminium compound, such as aluminium sulphate or polyaluminium sulphate, for precipitation of interfering substances, such as oxygen-demanding organic material and metals, that the precipitated material is removed from the filtrate, that the aluminium content of the filtrate after precipitation of interfering substances is adjusted to at most 20 ppm, and that the filtrate is then recirculated to the peroxide bleaching step. By the method, a reduced consumption of hydrogen peroxide in the peroxide bleaching step is achieved.

Abstract: A method of purifying sewage is described. The method relates to purifying sewage in sewage systems which comprise a toilet, by adding a precipitant for precipitation of phosphates and for binding organic substances. The method is characterized in that the precipitant is selected from the group consisting of iron salts and aluminum salts, such as sulphates, chlorides and nitrates and is adapted to be flushed with water in the toilet bowl when flushing. In the method, the sewage from the toilet is preferably conducted to a sludge separator through an outlet pipe which leads to the lower part of the sludge separator below its outlet.

Abstract: The present invention relates to a process for preparation of a granular composition, which comprises magnesium and phosphorus. In the process, magnesium oxide is granulated with addition of a granulating liquid, which contains phosphoric acid and water. According to the invention, the granulating liquid, besides phosphoric acid and water, also contains sulphuric acid.

Abstract: A sizing composition and a method of sizing a cellulosic fiber material are disclosed. The sizing composition comprises an aqueous dispersion of a rosin material and a polyaluminium compound, and is characterised in that the polyaluminium compound is a polyaluminium phosphate sulphate compound. The polyaluminium phosphate sulphate compound should comprise at least 5% by weight, calculated as aluminium on the amount of rosin material in the composition. It is preferred that the sizing composition also comprises a synthetic sizing agent in addition to the rosin material. The dispersion preferably also includes a dispersing agent and has a dry content of at least 1% by weight. The sizing composition is used for the sizing of cellulosic fibre materials, such as paper, board or paper board by adding 0.

Abstract: A method and an agent for improving the retention when dewatering a cellulosic fiber suspension are disclosed In the method, there is added to the suspension a retention agent containing a phenol-formaldehyde resin and a polyethylene oxide, and the method is characterised in that a modified phenol-formaldehyde resin containing cationic groups is added to the suspension. The modified phenol-formaldehyde resin preferably has a cationicity of about 5-85% and the cationic groups preferably consist of amine groups. The polyethylene oxide in the retention agent preferably has a molecular weight of about 0.5-20×106. The modified phenol-formaldehyde resin and the polyethylene oxide are preferably added to the suspension in a weight ratio of modified phenol-formaldehyde resin:polyethylene oxide of from 1:5 to 50:1, and the amount of polyethylene oxide added preferably is about 10-1000 ppm, based on tie dry solids content of the suspension.

Abstract: A method treats process water containing metal ions, in connection with bleaching of lignocellulosic pulp. The method is characterized by the steps of a) adjusting the Mg2+ content of the process water to form a flocculating base for metals and an organic substance; b) supplying a carbonate source to the process water to precipiate calcium as calcium carbonate; c) increasing the pH of the process water by adding white liquor to precipipate metals such as metal hydroxides; d) adding a flocculating agent to the process water; and e) separating the precipitated, flocculated metal compounds from the process water by flotation.

Abstract: A method for treating sludge from wastewater purification is described. In the method, a sludge is treated, which contains phosphorus and at least one metal which originates from precipitation chemicals and which is selected among divalent iron and aluminum, the pH of the sludge being adjusted to below 4, preferably below 2, for dissolving the content of the phosphorus and said metal in the sludge; the remaining sludge is separated; the solution relieved of sludge and containing phosphorus and said metal is treated for precipitation of the phosphorus content of the solution as FePO4 at a pH of 2-3; and precipitated FePO4 is separated. The method is characterized in that the solution which remains after separation of FePO4 and which contains said metal from the precipitation chemicals, is recycled to the wastewater purification. The phosphorus content of the solution is precipitated as FePO4 by adding an at least equivalent amount of Fe3−.

Abstract: A method for recovering at least one metal from an acidified waste water sludge by liquid-liquid extraction by providing an acidified waste water sludge containing ions of at least one metal and organic material, treating the waste water with an oxidizer to convert the organic material into a form that does not have an unfavorable effect on a subsequent liquid-liquid extraction, and subjecting the treated, acidified waste water sludge to a liquid-liquid extraction thereby obtaining an organic phase loaded with ions of said at least one metal, and subsequently recovering ions of said at least one metal from said organic phase.

Abstract: A process for the purification of solutions containing metals comprising neutralization of the solution, reduction of Fe(III) present, and elimination of ingoing dissolved zinc, whereby the ingoing solution containing metals is neutralized using magnetite and/or metallic iron, that the ingoing iron (III) is reduced to iron (II) by means of an addition of metallic iron, that ingoing heavy metals are precipitated by the addition of a precipitating amount of a sulphide, whereby the metal sulphides precipitated are recovered by means of filtration, that the solution is, optionally, subjected to an ion exchange operation to transfer ingoing zinc into non-complex bound form, whereupon zinc is recovered as zinc carbonate, that iron (II) in the remaining solution is oxidized to iron (III), whereupon the solution is used as such or is further treated for increasing the metal content for the purpose intended.

Abstract: The invention relates to a method for treating waste water sludge comprising at least one metal originating from a waste water treatment coagulant, and phosphorus and heavy metals in order to recover said at least one metal and phosphorus and to discharge said heavy metals. In this method said waste water sludge is acidified to dissolve metals contained in the sludge thereby yielding an acidified sludge solution containing at least 1% by weight of at least one metal to be recovered. In a first precipitation stage the pH of said acidified sludge solution is raised to precipitate at least one metal to be recovered as a phosphate, and thereafter the phosphate precipitate is separated, thereby leaving a solution comprising heavy metals. In a second precipitation stage the pH of said solution comprising heavy metals is raised and, if necessary, an appropriate chemical is added to precipitate heavy metals, and thereafter the precipitate is discharged.

Abstract: Waste water sludge which contains phosphorous, heavy metals and at least one metal originating from a waste water treatment coagulant, is treated in order to recover the phosphorous and the at least one metal, and to discharge the heavy metals. The at least one metal includes iron.

Abstract: A method for the treatment of sludge obtained from such a water treatment process wherein an aluminium or iron chemical is used as a coagulant, so as to reduce the amount of sludge, which method comprises the steps of:a) treating the water treatment sludge with an inorganic acid to produce an acidic sludge comprising dissolved aluminium or iron,b) optionally separating insoluble material from the acidic sludge to produce an acidic solution comprising dissolved aluminium or iron,c) treating said acidic sludge or said acidic solution with a +1-cation compound in the presence of sulphate ions in such conditions that the pH of the sludge or solution remains at a level where aluminium precipitates as an alunite compound or iron precipitates as a jarosite compound, andd) separating the precipitated alunite or jarosite compound from the remaining sludge.