Fp-pigments Oy

Kautar Oy

Metso Paper Inc.

Mesto Paper Oy

Pentti Virtanen

Vilho Nissinen

Timo Nyberg

Pasi Rajala

Veli K&auml;sm&auml;

Hannu Niemel&auml;

Lars Gr&ouml;nroos

Veli Käsmä

Lars Grönroos

Hannu Niemelä

A binder mix containing a hydraulic binding agent and an admixture mixed therewith, a process for preparing a hydraulically hardened binder mass, a calcinated kaolin product and a process for preparing the same. A paste-like composition is formed from the hydraulically hardening binding agent, a pozzolanically reacting admixture and water, which, when so desired, contains stone aggregate or similar filler, the paste-like composition is worked and the worked composition is allowed to harden to form the binder mass. The admixture comprises spherical, porous metakaolin agglomerates, the size of which is 2-200 microns and which have an open pore structure. The invention can be used to improve the manufacturing methods of cast concrete products and shorten the manufacturing times, and to provide concrete with better mechanical and chemical properties, as well as improve the fire and frost resistance of concrete.

Binder admixture, kaolin product and their manufacture

A paper, board or non-woven product containing a fiber layer containing cellulosic fibers, plant fibers or other material suitable for making a paper, board or non-woven product. One surface of the fiber layer is treated with pigment particles. The web is treated with microscopic particles whose average size is so small as to permit the particles to adhere to each other by van der Waals forces.

Paper having a cellulosic fiber layer treated with elementary particles

Apparatus for forming a paper or board web made from fibers in which the web is treated with calcium hydroxide and then with carbon dioxide gas so as to form calcium carbonate.

Apparatus for making a web of paper or board containing calcium carbonate

According to the process, limestone is burned at a high temperature to form calcium oxide and, thereafter, calcium carbonate is formed from calcium oxide in the presence of water and carbonate ions and the formed calcium carbonate is recovered. The formation of the carbonate may be performed by carbonating calcium oxide with carbon dioxide gas in the presence of water or water vapour, or by reacting calcium oxide with soda solution. According to the invention calcium oxide is converted to calcium carbonate without separate slaking and essentially without intermediate storage, in particular without intermediate storage between the burning of the starting material and the forming of calcium carbonate. With the aid of the invention a quite advantageous solution in view of heat economy is achieved.

Process for preparing precipitated calcium carbonate

The present invention concerns a process for preparing calcium carbonate pigment from calcium oxide and/or calcium hydroxide and carbon dioxide in the presence of water. According to the invention, the starting materials are reacted in fluid state containing at least 20 parts of volume of gas for each part by volume of suspension formed by water and solid substances, and the amount of water is essentially equivalent to the amount which is evaporated during the reaction together with the amount left in a calcium carbonate product which behaves like a powder. By means of the present invention, PCC in powder form can be prepared without the product first having to be separated from a slurry.

Process for preparing and modifying synthetic calcium carbonate

Method and assembly for forming a paper or board web and a product made using the method. According to the method, the web ( ) is made from fibers and then the web ( ) is treated with pigment particles. The web is treated with microscopic pigment particles whose average size is so small as to permit the particles to adhere to each other by van der Waals forces. The particles are transferred to the web and adhered thereto advantageously using an ion-blast technique.

Method for making paper, assembly for implementing the method and paper product produced by the method

The invention concerns precipitated calcium carbonate products containing polynuclear regular agglomerates having a number of calcium carbonate particles (aggregates) attached to each other and having a particle size of about 40 to 200 nm. According to the invention, these products are prepared by adjusting the Z potential of the calcium carbonate suspension to &minus;1 . . . &minus;20 mV by adjusting the pH of the suspension to 6.5 . . . 9.5. The pH of the calcium carbonate slurry obtained by causticizing is adjusted to a desired value in a box filter, where after the suspension is stirred by a heavy-duty mixer such that it is subjected to differences of about 50 to 200 m/s in peripheral speed. The products according to the invention have good opacity and are very well suited for coating paper.

Precipitated calcium carbonate and method for the production thereof

The invention is related to a method for forming calcium carbonate. In the method, calcium oxide is reacted with carbonate ions in the presence of water to produce calcium carbonate. According to the invention, the formation is carried out directly from calcium oxide to calcium carbonate without intermediate stages in a three-phase precipitation, whereby the hydration of the calcium oxide to calcium hydroxide and the carbonation of the hydrated part are carried out immediately after one another under so intensive agitation that the calcium carbonate elements thus created are detached from the surface of the calcium hydroxide. The mixing is preferably carried out in a fluid medium where the amount of gaseous phase is at least 20 parts by volume and the amount of liquid phase is 0.5 to 1 part per one part by volume of the solid matter of the suspension. In the process, the desired end product, PCC, can be prepared in a very short residence time and with a small operational content.

Process for preparing calcium carbonate particles

A process and an apparatus for the preparation of precipitated calcium carbonates calcium hydroxide using gaseous carbon dioxide, whereby the carbonation is performed in a gaseous phase by mixing calcium-hydroxide-containing liquor mist with the carbon dioxide gas in a turbulence having an energy intensity in excess of 1000 kW/m . The reaction is advantageously carried out in an apparatus, comprising at least two serially arranged pin mills having one or more rotatable vane rings which can be used to impose a great energy intensity on the material which is fed into the apparatus, whereby the first pin mill is provided with at least an inlet for slaked lime and carbon dioxide and an outlet for the reaction product, and the second pin mill is provided with an inlet for the product from the previous mill and an outlet for the reaction product. Carbonating is extremely swift. The residence time of the reaction is even less than 1 second. Due to the high energy intensity, carbonation may be performed at high solids contents.

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Toijala, Finland

Pentti Virtanen