Nordkalk
Limestone-based solutions for industry, agriculture and environmental care
Products
Use of products
Pulp & paper
Pulp
Paper is made from pulp, cellulose, which is obtained by cooking wood chips in a strong lye solution. Chemicals from the cooking process circulate in the recovery line of the pulp mill where the composition can be chemically adjusted by the addition of quicklime to the causticising process. During the process of making pulp the lime mud, sludge, is slaked in a slaker, after which causticising takes place and the lime carbonates. The pulp mill then burns the sludge in its own kiln. Since some of the lime mud evaporates in the course of the process, it is replaced with new quicklime so that the reactivity is maintained at as much the same level as possible as that of the sludge lime.
Paper pigments PCC and GCC
The paper industry uses limestone-based products as fillers and coating pigments. Paper of a high quality contains considerable amounts of minerals since they serve to improve the paper’s printing properties, make it opaque and increase whiteness and gloss.
Limestone is the raw material for two types of paper pigment: GCC (ground calcium carbonate) and PCC (precipitated calcium carbonate). Both types of pigment are used in magazines and advertising paper, packaging and copying paper.
Nordkalk refines calcite from its quarry in Lappeenranta, Finland. The processed calcite is further refined for use as paper pigment GCC, which is manufactured by Nordkalk’s subsidiary Suomen Karbonaatti Oy in Lappeenranta.
PCC is made of quicklime which Nordkalk produces at Tytyri in Lohja, Finland and at Storugns in Sweden. The raw material is shipped from Verdal, Norway, where Nordkalk co-owns a quarry. Some quicklime for PCC is also produced at Louhi and Lappeenranta.
The Norwegian company NorFraKalk AS, which is owned in half by Nordkalk Corporation and Franzefoss Minerals AS, has built a lime kiln in Verdal, Norway. The raw material for the kiln comes from the Verdal quarry and is especially suitable for raw material for paper pigment PCC. The yearly capacity of the new kiln will be 200 000 tons of quicklime. The kiln was started up in the end of 2007.