The wood raw material contains the cellulose fibres that become pulp. The production process is based on separating these cellulose fibres from by-products. The by-products are then taken care of in a number of other cycles, one of which is energy. Even chemicals are recycled. Production is highly automated and almost everything is controlled and managed by computers.
The first thing that happens when pulp comes to the mill is that the bark is removed. It is collected and burned to create heating energy, sometimes after having been pressed into pellets. The wood that is stripped of its bark is chopped into chips. To separate the cellulose fibres in the wood, the chips are cooked. The cellulose is then washed and bleached. When the last unwanted by-products have been removed from the pulp, it is dried and cut into appropriately-sized sheets that are strapped together into bales for transporting on to paper mills.
The idea behind our softwood concept is wood segregation. Three kinds of raw material enter Södra’s woodyards; softwood thinnings, roundwood and sawmill chips. These different materials are mixed carefully to achieve different paper properties.
Paper pulp Södra black Södra green Södra blue Södra gold
Dissolving pulp Södra orange Södra purple
This is how we have designed our softwood product groups. Sawmill chips are the main component of green pulps, while our black range is predominantly thinnings and blue pulps are mainly roundwood.
Two of our mills, Södra Cell Värö and Södra Cell Mönsterås, use TCF (total chlorine free) bleaching sequences and the third, Södra Cell Mörrrum has an ECF (elementary chlorine free) bleaching sequence. This gives Södra the possibility to produce and sell both TCF and ECF products. TCF pulps have a Z in the product name.
A third component used in our branding is brightness, however all of our pulps are not fully bleached. Within all three groups we have pulp with 85 brightness and in the green group we also offer a pulp with 70 brightness.
A fourth factor is the drying method, either sheet or flash dried. Flash-dried pulp has the letter F in the name.
Södra's paper pulp consists of a mixture of primarily cellulose and hemicellulose. The dissolving pulp is a pure cellulose product where the hemicellulose is removed. The reason is that dissolving pulp is sold and used for its chemical properties, while paper pulp is sold for its mechanical properties, for example, its strength.
Dissolving pulp received its name from the English word dissolve. To create products from dissolving pulp, the cellulose in the pulp must be dissolved.
The textile market is a growing market and that’s the reason why Södra wants to be a part of this. The viscose industry its gaining market share from cotton and polyester. Södra and our customers very much believe in investing in this industry also in the future.
Replacing synthetic, oil-based fibre with fibre from forest raw material can significantly reduce the greenhouse gas effect. Substantial environmental gains can also be achieved by using forest-based textile fibres instead of cotton.