Abstract: The present invention concerns a particulate agent for chemical and/or physical treatment of a fluid, such as a gas containing NO.sub.x and SO.sub.x, contains at least two particle types of different activity, the particle weight and/or particle size of each type lying within separate ranges. The agent may also contain catalyst particles for reducing NO.sub.x, and particles for absorbing SO.sub.x.The invention also concerns a method and a plant for treating a fluid with the inventive particulate agent.

Abstract: The invention concerns a method of preparing brine by dissolving salt in water, the salt containing sodium chloride but also calcium sulfate and/or other soluble impurities with a slower dissolution rate than sodium chloride, wherein the salt is supplied to a vessel including a grid for supporting a salt bed, water is supplied and flows through and wets at least a portion of the salt bed before it flows through the grid, whereby small solid particles form and pass through the grid whereafter they are separated from the solution, said small particles containing essentially no sodium chloride.The invention further concerns a device for making brine by dissolving salt in water, which device comprises a vessel containing a grid support, means for supplying solid salt, means for supplying water, means for the outflow of brine, and means for removing undissolved salt particles at the bottom of the vessel.

Abstract: The invention discloses a method in the electrolytic production of alkali metal chlorate which is recovered by crystallization and separation of the crystals from a solution recycled to the electrolysis process. A given proportion of the crystals formed are separated and removed from the mother liquor after they have been in contact with the mother liquor for a shorter period of time than the remaining crystals, whereby they obtain a sulphate content which is higher than in the crystals that have been in contact with the mother liquor for a longer period of time.

Abstract: A process for the production of essentially chlorine free chlorine dioxide whereby a flow of chlorine dioxide obtained from reduction of alkali metal chlorate and containing by-product of chlorine gas is absorbed in water and the chlorine gas is treated with formic acid in the water solution. The formic acid is added in an amount resulting in a mole ratio formic acid to chlorine gas of >1:1.

Abstract: A method of maintaining a given content of a substance A in an aqueous solution where it is continuously consumed and where the redox potential E, at least within the range of concentration used, approximately satisfies the equation:E=G+F(x)wherein x is the content of A, F is a function of x whose derivative dF/dx approaches zero when x assumes a high value, and G on the whole is independent of x but is influenced by other parameters, such as pH, temperature or the like. The addition of A is controlled in such manner that a set value of the redox potential is maintained. The set value is determined by increasing or decreasing the addition of A in a predetermined manner, whereupon the redox potential is measured, and the measured value is used for determining the set value.

Abstract: The present invention relates to a method of reducing the content of halogenated organic compounds in the spent bleach liquor from the bleaching of lignocellulose-containing material with compounds containing halogen, wherein the spent bleach liquor, in a stage where no essential delignification or bleaching of the pulp takes place, is maintained at a pH of from 2.5 up to about 10, and wherein the residence time and the temperature are selected such that the amount of dissolved halogenated organic substances in the spent bleach liquor is reduced by at least 30%.

Abstract: The invention describes a procedure for production of chlorine dioxide where, in a primary reactor chlorate, sulphuric acid and a reducing agent with optional extra additions of chloride ions are reacted, the resulting gas mixture mainly containing chlorine dioxide and air are forced through a scrubber to an absorption tower for absorption of the product gas. Where the reactor solution is withdrawn from the reactor optionally to a secondary reactor in which reducing agent is also added, the procedure being characterized by that of the primary reactor solution is recirculated optionally via a cooler to the upper part of a scrubber and then returned to the reactor.

Abstract: A process for delignification and bleaching of chemically digested lignocellulose-containing pulp for reduced formation and discharge of halogenated organic compounds, while preserving the pulp quality, where the prebleaching with halogen-containing bleaching agent is replaced by a treatment, in a first step, with the addition of a complexing agent at elevated temperature and at a pH from 3.1 to 9.0, and in a second step, by using a peroxide-containing compound under alkaline conditions, whereupon spent liquor from the final bleaching with halogen-containing compounds is recycled to the first or second step of the halogen-free prebleaching.

Abstract: A process for the production of paper by forming and dewatering a suspension of cellulose containing fibres, and optional fillers, on a wire. The forming and dewatering is carried out in the presence of a combination of an aluminum compound, a cationic retention agent and a polymeric silicic acid having a high specific surface area. The combination of substances improves dewatering and retention of fines and fillers.

Abstract: New 9-anthrylalkyl compounds having the general formula ##STR1## wherein R is hydrogen or an alkyl group, whereby, however, not more than one of the groups R is an alkyl group; R.sub.1 is hydrogen, lower alkyl, halogen or nitro; n is an integer of from 1 to 7, whereby, however, the total number of carbon atoms in the group --CHR--(CHR).sub.n -- does not exceed 8; and X is halogen, an azide group or a succinimidyl group.The new compounds are prepared from 9-anthrylalcohols which are reacted with a compound X--CO--X wherein X is a halogen, and then optionally with compounds giving azide or succinimidyl group. The compounds are used as derivatization reagents for separation and detection purposes.Intermediates for preparation of the above defined 9-anthrylalkyl compounds wherein one R is an alkyl group are 9-anthrylalcohols with the group --CHR--(CHR).sub.n --OH, wherein one R is an alkyl group.

Abstract: A process for the production of chlorine dioxide by reacting in a reaction vessel an alkali metal chlorate, mineral acid and a reducing agent in such proportions that chlorine dioxide is produced in a reaction medium which is maintained at a temperature of from about 50.degree. C. to about 100.degree. C. and at an acidity within a range of from about 2 to about 11N and which is subjected to subatmospheric pressure sufficient for evaporating water. A mixture of chlorine dioxide and water vapor is withdrawn from an evaporation zone in the reaction vessel, and alkali metal sulfate is precipitated in a crystallization zone in the reaction vessel. Straight chained alcohols with the formula CH.sub.2 OH(CHOH).sub.n CH.sub.2 OH where n=0-5, are used as reducing agents. Preferred reducing agents consist of glycol or glycerol. The reaction may also be performed in the presence of a catalyst.

Abstract: A process for the production of chlorine dioxide by reacting in a reaction vessel an alkali metal chlorate, mineral acid and a reducing agent in such proportions that chlorine dioxide is produced in a reaction medium which is maintained at a temperature of from about 50.degree. C. to about 100.degree. C. and at an acidity within a range of from about 2 to about 5N. The reaction medium is subjected to subatmospheric pressure sufficient for evaporating water, a mixture of chlorine dioxide, oxygen and water vapor being withdrawn from an evaporation zone in the reaction vessel, and alkali metal sulfate being precipitated in a crystallization zone in the reaction vessel. As the reducing agent hydrogen peroxide is used.

Abstract: A process for the production of chlorine dioxide by reacting in a reaction vessel an alkali metal chlorate, mineral acid and a reducing agent in such proportions that chlorine dioxide is produced in a reaction medium which is maintained at a temperature of from about 50.degree. C. to about 100.degree. C. and at an acidity within a range of from about 5N to about 11N. The reaction medium is subjected to subatmospheric pressure sufficient for evaporating water, a mixture of chlorine dioxide, oxgen and water vapour being withdrawn from an evaporation zone in the reaction vessel, and alkali metal sulfate being precipitated in a crystallization zone in the reaction vessel. As the reducing agent hydrogen peroxide is used.

Abstract: The invention relates to a catalyst for the reduction of nitrogen oxides and comprises oxides of transition metals on a particulate carrier material, the catalyst comprising:1) a carrier material consisting of small grains of an inorganic oxide,2) a catalytic layer thereon containing TiO.sub.2 and V.sub.2 O.sub.5, and obtained by a separate or simultaneous coating of the components on the carrier material,the catalyst particles being in the order of 10-200 .mu.m and the catalyst being intended to operate at temperatures of 150.degree.-220.degree. C.The invention also relates to a method for the preparation of the catalyst, and the use thereof for the reduction of nitrogen oxides in gases at low temperatures.

Abstract: The invention relates to a process for the reduction of the perchlorate content in electrolytes for chlorate production, whereby the electrolyte is subjected to the following process steps:a) a part of the flow of an electrolyte leaving the chlorate process is evaporated at an elevated temperature of from 30.degree. to 110.degree. C. and/or at a reduced pressure to a reduction in liquid volume of from 1 to 4 times,b) the product from the previous step is cooled to a temperature of from 30.degree. to 0.degree. C.,c) to the product from the previous step is added a potassium chloride solution with a concentration of at least 1.0 mole/l up to the saturation concentration,d) the product from the previous step is relieved of solid phase and recirculated to the chlorate process.

Abstract: The invention relates to a process in the continuous catalytic hydrogenation step during production of hydrogen peroxide according to the anthraquinone process by alternate reduction and oxidation of a working soloution of alkylated anthraquinones, said working solution being supplied at the upper end of the hydrogenation reactor and uniformly distributed across the surface of the monolithic catalyst bed, while simultaneously introducing hydrogen gas or hydrogen gas-containing gas, the flow of said working solution through the catalyst bed being adjusted such that the liquid flow is lower than the falling rate of the liquid through the bed, whereby gas bubbles are formed which have a diameter close to the diameter of the catalyst channels, and whereby such gas plugs and corresponding liquid plugs alternately and automatically flow downwardly through said channels and a so-called plug flow is obtained.

Abstract: A process for a continuous production of chlorine dioxide in a cooled reaction vessel subjected to an overpressure, comprising continuous addition of an aqueous solution of an alkali metal chlorate, sulfuric acid and sulfur dioxide to the reaction vessel in proportions to generate chlorine dioxide at a temperature from about 30.degree. to about 60.degree. C. and at an acidity of about 5 to about 11 N. The reaction solution containing dissolved chlorine dioxide is continuously withdrawn. At the start up of the process the reaction vessel is filled with the water solution of alkali metal chlorate, optionally containing alkali metal chloride, and the sulphuric acid with a feed concentration of from about 20 to about 60 percent by weight whereafter the flows are adjusted to correspond to the production rate. Finally sulfuric dioxide is added so slowly that no gas phase is formed and the sulphuric acid flow is slowly increased until the suitable flow for the chosen production is reached.

Abstract: The invention relates to a process for the preparation of an acid-resistant coating and calcium carbonate particles, in which process a slurry of calcium carbonate particles is mixed simultaneously with the solution of a zinc compound and a solution of a silica-containing substance at a temperature of 70.degree.-95.degree. C., the pH being maintained at 8-11.The invention also relates to calcium carbonate particles having an acid-resistant coating in accordance with the above-mentioned process.In addition, the invention relates to the use of calcium carbonate particles having a acid-resistant coating in accordance with the above-mentioned process, as an acid-resistant filler in the production of paper at pH 4.0-7.0.

Abstract: New 9-anthrylalkyl compounds having the general formula ##STR1## wherein R is hydrogen or an alkyl group, whereby, however, not more than one of the groups R is an alkyl group; R.sub.1 is hydrogen, lower alkyl, halogen or nitro; n is an integer of from 1 to 7, whereby, however, the total number of carbon atoms in the group --CHR--(CHR).sub.n -- does not exceed 8; and X is halogen, an azide group or a succinimidyl group.The new compounds are prepared from 9-anthrylalcohols which are reacted with a compound X--CO--X wherein X is a halogen, and then optionally with compounds giving azide or succinimidyl group. The compounds are used as derivatization reagents for separation and detection purposes.Intermediates for preparation of the above defined 9-anthrylalkyl compounds wherein one R is an alkyl group are 9-anthrylalcohols with the group --CHR--(CHR).sub.n --OH, wherein one R is an alkyl group.

Abstract: The present invention relates to a process for production of chlorine dioxide by reacting in a reaction vessel an alkali metal chlorate, a mineral acid and methanol as a reducing agent in proportions to generate chlorine dioxide in a reaction medium maintained at a temperature from about 50.degree. C. to about 100.degree. C. and an acidity within the interval from a b out 2 to 4.8 N and subjected to a subatmospheric pressure sufficient to effect evaporation if water. A mixture of chlorine dioxide and water vapor is withdrawn from an evaporation region in the reaction vessel and an alkali metal salt of the mineral acid is precipitated in a crystallization region in the reaction vessel.