Patents Assigned to Kemira Chemical OY
  • Patent number: 6814949
    Abstract: The invention relates to a process for producing simultaneously food-grade and fodder-grade phosphoric acid by crystallizing phosphoric acid hemihydrate, H3PO4×0.5H2O, from a prepurified feed acid, which is purified and crystallized with the help of the following steps, a) after the step of froth-flotation of phosphate concentrate, the concentrate is directed to a strongly magnetic separation step in order to decrease the Mg ion amount, b) the phosphate concentrate is leached in a mixture of sulfuric acid and phosphoric acid according to the wet process, the precipitated SO4 and As ions are removed, and a silicon source is added in order to adjust the F/Si molar ratio to <6, c) the phosphoric acid is concentrated, the solids precipitate is removed, and the F ions are evaporated, d) the feed acid obtained from step c, having a concentration of >58% P2O5, solids concentration of <0.05%, Mg ion concentration of <1.
    Type: Grant
    Filed: November 14, 2001
    Date of Patent: November 9, 2004
    Assignee: Kemira Chemicals Oy
    Inventors: Jarmo Aaltonen, Sakari Riihimäki, Paula Ylinen, Anders Weckman
  • Patent number: 6749727
    Abstract: A method of hydrogenating alkyl anthraquinones and/or alkyl hydroanthraquinones to alkyl anthrahydroquinones and/or alkyl hydroanthrahydroquinones is disclosed. The reaction is carried out in the presence of a catalyst under electromagnetic irradiation, such as microwave irradiation. The invention further relates to a method of hydrogenating a working solution in a hydrogen peroxide production process, wherein the working solution contains alkyl anthraquinones and/or alkyl hydroanthraquinones dissolved in at least one solvent to convert the quinines to the corresponding alkyl anthrahydroquinones and/or alkyl hydroanthrahydroquinones, where the reaction is carried out in the presence of a catalyst under electromagnetic irradiation such as microwave irradiation.
    Type: Grant
    Filed: March 14, 2002
    Date of Patent: June 15, 2004
    Assignee: Kemira Chemicals Oy
    Inventors: Reijo Aksela, Juhani Paloniemi
  • Patent number: 6712934
    Abstract: The invention relates to a method for the production of paper or board, wherein retention aids are added to the stream of stock. Improved retention and more effective dewatering are achieved by adding to the stream of stock a cationic polymer solution and a suspension-form microparticle mixture composed of a swellable clay of the smectite group and a colloidal synthetic metal silicate in which the prevalent cation is magnesium.
    Type: Grant
    Filed: May 31, 2002
    Date of Patent: March 30, 2004
    Assignee: Kemira Chemicals Oy
    Inventors: Jonni Ahlgren, Kimmo Strengell
  • Patent number: 6689377
    Abstract: The invention relates to a solid antimicrobial product suitable for the preservation of an organic material and for combating of detrimental microorganisms, as well as for pH control. The product contains, absorbed into a support a concentrated formic acid partly neutralized with gaseous ammonia, the water content of the formic acid being below 2% by weight. In addition, the invention comprises a method for preparing the product.
    Type: Grant
    Filed: October 23, 2002
    Date of Patent: February 10, 2004
    Assignee: Kemira Chemicals Oy
    Inventors: Eero Aitta, Jouko Arvola, Pekka Johnson, Juha Kangastalo, Marjo Luoma, Ilkka Pollari
  • Patent number: 6677478
    Abstract: The conventional process for the production of a peracetic acid product, wherein hydrogen peroxide, acetic acid and water are fed into an aqueous reaction medium containing hydrogen peroxide, acetic acid, peracetic acid and an acid catalyst, wherein hydrogen peroxide and acetic acid react in the presence of the acid catalyst and form peracetic acid, and an aqueous peracetic acid concentrate is removed continuously from the reaction medium by distillation, has now been improved by feeding the acid catalyst continuously into the reaction medium and by withdrawing continuously a portion of the reaction medium as a bottom product. When the through flow of the reaction medium is thus increased, it is purified of impurities threatening the safety of the process. If the amount of acid catalyst in the reaction medium is further decreased, a product suitable, for example, for disinfection is obtained from the bottom product.
    Type: Grant
    Filed: April 3, 2002
    Date of Patent: January 13, 2004
    Assignee: Kemira Chemicals Oy
    Inventors: Seppo Pohjanvesi, Eva-Liisa Mustonen, Arto Pukkinen, Reino Lehtinen
  • Patent number: 6677477
    Abstract: The reaction medium and distillate of a conventional continuous peracetic acid process can be combined into a stable peracetic acid product if the acid catalyst present in the reaction medium is neutralized.
    Type: Grant
    Filed: April 3, 2002
    Date of Patent: January 13, 2004
    Assignee: Kemira Chemicals Oy
    Inventors: Seppo Pohjanvesi, Arto Pukkinen, Teemu Sodervall
  • Patent number: 6590120
    Abstract: Methods for the preparation of an N-alkyl-N-bis-(2-( 1,2-dicarboxy-ethoxy)-ethyl)-amine derivative are described, products of the methods as well as uses of the products. The derivative is prepared by reacting an alkali or earth alkali metal salt of maleic acid with an N-substituted diethanolamine, the reaction taking place with the two ethanol groups of the diamine while the substituent group bound to the N atom remains unaffected, or alternatively by first reacting diethanolamine with an alkali or earth alkali metal salt of maleic acid to yield N-bis-(2-(1,2-dicarboxy-ethoxy)-ethyl)-amine, which is then reacted with a substitution reagent to obtain the final product. The derivative is useful as chelating agents, e.g., in the bleaching of chemical or mechanical pulp or in textile bleaches containing hydrogen peroxide or a peracid, or as a calcium binder in detergents and cleaning agents.
    Type: Grant
    Filed: September 8, 2000
    Date of Patent: July 8, 2003
    Assignee: Kemira Chemicals Oy
    Inventors: Reijo Aksela, Ilkka Renvall, Aarto Paren
  • Patent number: 6492551
    Abstract: A method for manufacturing alkali metal or alkaline-earth metal formate, starting from a formate anion comprises at least the following sequential steps: A) conversion of a solid anion exchanger to formate form by feeding into it a solution containing a formate anion, B) exchanging the formate anion in the anion exchanger for a replacing anion by feeding into it an alkali metal or alkaline-earth metal salt solution of this replacing anion, C) recovering the alkali metal or alkaline-earth metal formate solution eluted from the anion exchanger during the exchange of the formate anion. The anion exchanger is converted to formate form by feeding into it a sodium formate solution, a formic acid solution or a solution which contains both sodium formate and formic acid. The method can be used for production of potassium formate or calcium formate.
    Type: Grant
    Filed: April 16, 2001
    Date of Patent: December 10, 2002
    Assignee: Kemira Chemicals OY
    Inventors: Erkki Paatero, Marko Lahtinen, Kari Saari, Pekka Vapaaoksa
  • Publication number: 20020141930
    Abstract: A method for the preparation of sodium percarbonate granules having enhanced stability, comprising modifying the surface of the sodium percarbonate granules by a surface reaction between sodium percarbonate and carbon dioxide or bicarbonate species to form a dense solid film of essentially sodium bicarbonate on the surface of the sodium percarbonate granules, the method comprising the steps of:
    Type: Application
    Filed: January 28, 2002
    Publication date: October 3, 2002
    Applicant: KEMIRA CHEMICALS OY
    Inventors: Olof Norrlow, Pentti Pekonen
  • Patent number: 6429333
    Abstract: In a method for preparing formic acid, methyl formate is prepared with methanol as a reactant.
    Type: Grant
    Filed: June 19, 2001
    Date of Patent: August 6, 2002
    Assignee: Kemira Chemicals Oy
    Inventors: Kari Saari, Esko Tirronen, Antti Vuori, Marko Lahtinen
  • Patent number: 6387998
    Abstract: The invention relates to a process for preparing a cationically modified (meth)acrylamide polymer by the Mannich reaction. There is prepared in advance a stable aldehyde-secondary amine adduct, which is obtained as a reaction product of an aqueous solution of the secondary amine and an aqueous solution of the aldehyde, and which, after the formation of the adduct, is stabilized to endure storage, by lowering the pH of the mixture of 7 or below and/or by adding methanol, and the adduct thus prepared is added to an aqueous solution of the (meth)acrylamide polymer and the pH is adjusted to an alkaline level, whereupon modification occurs. The invention also relates to the use of the modified (meth)acrylamide polymer as a flocculation, retention or dewatering agent.
    Type: Grant
    Filed: April 13, 2000
    Date of Patent: May 14, 2002
    Assignee: Kemira Chemicals Oy
    Inventors: Jonni Ahlgren, Lars Petander, Jussi Nikkarinen
  • Patent number: 6372035
    Abstract: The invention relates to a hydrophobising system for paper or a similar fiber product, comprising (1) a ketene dimer, and (2) an alkenyl and/or alkyl succinic acid and/or a salt thereof. The invention additionally relates to a method for hydrophobising paper or a similar fiber product comprising adding a hydrophobising system defined above to fibers.
    Type: Grant
    Filed: July 25, 2000
    Date of Patent: April 16, 2002
    Assignee: Kemira Chemicals Oy
    Inventors: Ari Juppo, Philip Håkansson
  • Patent number: 6331192
    Abstract: The invention relates to a process for the bleaching of chemical pulp, wherein the pulp is delignified and/or bleached with chlorine dioxide or with a combination of chlorine dioxide and a per-compound, and additionally the pulp is chelated in order to bind heavy metals, such as Fe, Mn and/or Cu, to a chelate complex. The chelate complex is selected from the group made up of N-bis-[(1,2-dicarboxylethoxy)-ethyl]-amine, N-bis[(1,2-dicarboxylethoxy)-ethyl]-aspartic acid and N-tris-[(1,2-dicarboxylethoxy)-ethyl]-amine, and the alkali metal and earth-alkali metal salts of these, and the chelating treatments are carried out simultaneously by combining the chelating chemical with the pulp in the same bleaching stage as chlorine dioxide.
    Type: Grant
    Filed: June 30, 2000
    Date of Patent: December 18, 2001
    Assignee: Kemira Chemicals Oy
    Inventors: Jukka Jäkärä, Reijo Aksela, Aarto Parén, Ilkka Renvall
  • Patent number: 6270564
    Abstract: The invention relates to a process for the bleaching of a mineral pigment or a synthetic pigment, in which process the pigment to be bleached is contacted with a solution which contains peracetic acid in order to obtain a pigment with a raised degree of brightness.
    Type: Grant
    Filed: February 24, 1999
    Date of Patent: August 7, 2001
    Assignee: Kemira Chemicals Oy
    Inventor: Pentti Hukkanen
  • Patent number: 6270738
    Abstract: The invention relates to a process for preparing a usable product, in particular a water treatment solution which contains ferric iron, from an impure ferric sulfate solution which contains as an impurity at least one other metal, the process comprising a first precipitation step in which a base is added to the said impure ferric sulfate solution in order to raise the pH to approx. 2-5, preferably approx. 3-4, whereupon ferric hydroxide precipitates; following the first precipitation step, a second precipitation step in which there are added to the solution an oxidant and a base to raise the pH to approx. 6-10, preferably approx. 8-9, whereupon the said impurity metal precipitates; and one or more separation steps to separate from the sulfate solution the solids precipitated in the first and the second precipitation steps; as well as possibly an additional step in which the said separated solids, or a portion thereof, are treated further in order to form a usable product.
    Type: Grant
    Filed: October 20, 1999
    Date of Patent: August 7, 2001
    Assignee: Kemira Chemicals OY
    Inventors: Simo Jokinen, Stefan Jäfverström, Timo Kenakkala
  • Patent number: 6264790
    Abstract: A process for the bleaching of chemical pulp, in which process the pulp is delignified with a peracid and additionally the pulp is chelated in order to bind heavy metals, such as Fe, Mn and/or Cu, into a chelate complex. According to the invention, the chelating is carried out using a chemical which has been selected from a group consisting of N-bis-((1,2-dicarboxy-ethoxy)-ethyl)-amine, N-bis-((1,2-dicarboxy-ethoxy)-ethyl)-aspartic acid and N-tris-((1,2-dicarboxy-ethoxy)-ethyl)-amine, as well as the alkali metal and earth-alkali metal salts thereof, and the peracid and chelating treatments are carried out simultaneously by combining the peracid and the said chelating chemical in the same solution phase. In the bleaching sequence the treatment according to the invention may follow, for example, an ozone delignification and precede an alkaline peroxide step, and in the latter case a magnesium compound, such as MgSO4, may be added to the pulp before the alkali step.
    Type: Grant
    Filed: November 24, 1998
    Date of Patent: July 24, 2001
    Assignee: Kemira Chemicals Oy
    Inventors: Jukka Jäkärä, Aarto Paren, Reijo Aksela, Ilkka Renvall
  • Patent number: 6262008
    Abstract: The invention relates to a stable sodium carbonate peroxyhydrate which is suited for use together with crystalline synthetic silicate-based detergents and is coated with an alkali metal sulfate and a copolymer or terpolymer of vinyl pyrrolidone.
    Type: Grant
    Filed: September 13, 1999
    Date of Patent: July 17, 2001
    Assignee: Kemira Chemicals Oy
    Inventors: Ilkka Renvall, Timo Korvela
  • Patent number: 6187143
    Abstract: The invention relates to a process for the manufacture of hydrophobic paper or board by using rosin sizing, an organic complexing agent being used together with the rosin size. The invention also relates to a sizing composition.
    Type: Grant
    Filed: August 27, 1999
    Date of Patent: February 13, 2001
    Assignee: Kemira Chemicals OY
    Inventors: Ari Juppo, Aarto Paren
  • Patent number: 6165318
    Abstract: A process for the delignification of a chemical pulp, such as a sulfate or sulfite pulp, in which process the pulp is treated with a peroxide and/or a peracid in the presence of an activating Ti-, V- or Cr-group transition metal, such as molybdenum, vanadium or tungsten. A compound containing at least one heteroatom, such as Si, P or B, which is capable of forming a heteropolyacid with the activating transition metal, is added to the pulp. The feeding of the activating transition metal and the heteroatom into the pulp may take place in one and the same alkaline solution, for example introduced into the solution or in the form of a compound of the silicomolybdenic acid type, formed in the solution. The peroxide and/or peracid treatment may constitute part of the bleaching sequence, which contains as potential other treatment steps, for example, a treatment with oxygen and a chelation for the removal of heavy metals such as iron, manganese and/or copper.
    Type: Grant
    Filed: February 27, 1997
    Date of Patent: December 26, 2000
    Assignee: Kemira Chemicals OY
    Inventors: Aarto Paren, Jukka Jakara, Juha Patola
  • Patent number: 6093849
    Abstract: The invention relates to N-bis- or N-tris-[(1,2-dicarboxy-ethoxy)-ethyl]-amine derivatives having the formula (I) ##STR1## and R.sub.2 is hydrogen, an alkali metal or an earth-alkali metal. The invention also relates to a method for preparing the same and their use as chelating agents.
    Type: Grant
    Filed: November 24, 1998
    Date of Patent: July 25, 2000
    Assignee: Kemira Chemicals Oy
    Inventors: Reijo Aksela, Ilkka Renvall, Arto Paren