Upm-kymmene Corporation

Wetend Technologies Oy

Upm-kymmene Oyj Corporation

Paivi Solismaa

Jouni Matula

Olavi Imppola

A method and apparatus for in-line production of milk of lime into an in-line production process of PCC arranged in connection with a fibrous web machine. In the solution, lime is slaked in a slaking apparatus at a temperature of at least 80 degrees. The produced milk of lime is cleaned by separating excessively large calcium hydroxide particles immediately prior to introducing the milk of lime into the production process of PCC. The milk of lime is introduced into the in-line production process of PCC located in the production line of the end or intermediate product of the fibrous web machine.

Method and apparatus for in-line production of milk of lime into an in-line production process of PCC arranged in connection with a fibrous web machine

The invention relates to a method for precipitating calcium carbonate, in which method calcium hydroxide is introduced to a fiber suspension containing cellulose-containing fibers, the calcium hydroxide is allowed to attach onto the surfaces of fibers for a pre-determined time, and the aqueous suspension of calcium hydroxide and fibers is brought into contact with carbon dioxide for precipitating the calcium carbonate. The invention also relates to a corresponding system for precipitating calcium carbonate in connection with cellulose-containing fibers. In addition, the invention relates to a fibrous product, which comprises pulp material produced by said method and comprising calcium carbonate.

Method for precipitating calcium carbonate

A method for production of calcium carbonate in a target suspension of a fibrous web forming process of a fibrous web machine, wherein the calcium carbonate is produced in a reactor, the method includes: injecting a chemical including carbon dioxide or lime milk through an injection mixer to the target suspension flowing through the reactor; allowing the chemical including to react while in the target suspension to form calcium carbonate crystals, and inhibiting precipitation of the chemical or a reaction product of the chemical on a surface of or in the reactor by application of an electric or magnetic field to or proximate to the surface along a region of the surface adjacent to the reaction involving the chemical.

Growing community of inventors

Lappeenranta, Finland

Paivi Solismaa