Paper and paperboard manufacturing processes involve the use of a number of fillers and coating pigments, such as clay, calcium carbonate, gypsum and talc. Before being used in paper and board production to improve printability and the optical properties of papers and boards, natural pigments are processed to fulfil specific requirements such as size, shape and distribution.
Fillers and pigments are supplied either in solid form or as slurry to the mills. Precipitated calcium carbonate (PCC) is very often produced on the mill site.
M-real uses various chemicals in the production processes, such as cooking and bleaching of pulp and coating of papers and boards. Most of the chemicals used in chemical pulp production are recovered and reused and only about one per cent needs to be replenished.
The main cooking chemicals are hydroxide and hydrosulphide ions as active components. The chemicals used in the pulp bleaching process depend on the brightness and strength requirements of different pulps. The main chemicals are oxygen, hydrogen peroxide and chlorine dioxide. No elemental chlorine is used by M-real mills.
Board and paper mills use various binders, including starches made, e.g. from potato or maize and synthetic-based latexes. The binders are mainly used for coating. To ensure the good runnability of board and paper production processes, various auxiliary chemicals, such as biocides and retention agents, are also used. Some chemicals are used in the power plants and waste water purification plants.
To continually minimise potential risks caused by chemicals, M-real’s mills only use chemicals with low environmental, health and safety risks; they also store, handle and use chemicals as instructed and with caution. Environmental and safety experts at the mills carry out risk analyses before new chemicals are taken into use and ensure that potential safety measures are in place if needed. Mills also train their employees to manage and minimise risks in different mill applications.