Pigments, fillers and many other types of chemicals are an essential part of pulping and papermaking processes. These additional substances can make up as much as 30–50% of the weight of the finished paper product.

In the pulping process, chemicals are used for cooking, bleaching and improving the efficiency of pulp production. Many of these chemicals are recovered for reuse in the pulping process, or diverted to energy production.

In the paper manufacturing process, pigments and fillers like calcium carbonate, clay, talc and other chemicals like binders, starch and retention chemicals are used to increase strength, opacity and brightness, and to provide smooth surface characteristics for quality printing and packaging applications. Other chemicals are also added to various mill support processes such as boilers and waste water treatment facilities to optimise system performance.

In 2004, Stora Enso purchased about 3 million tonnes of pigments and fillers. Unlike the fibres in pulp, many of these pigments and fillers are non-renewable, which makes the efficient use and recovery of these materials even more important.

 

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