At first glance, paper, plastic, paint, fillers, rubber and pills appear to have nothing in common. But when you start to examine their manufacturing processes, you find at least one common denominator: pigments as a raw material.
Kemira’s Business Line Manager Juha Savolainen says that worldwide demand for white pigment products is accelerating rapidly: “Pigments are used for two reasons: to lower production costs and for better technological properties.”
Kemira supplies products and services for the white pigments market, which in Kemira’s view includes the calcium carbonate, kaolin clay, talc and titanium dioxide pigment markets: “Our product assortment includes grinding aids, dispersants, defoamers and biocides for preserving pigment slurries, as well as chemicals for treating water that enters and exits the process.”
The paper industry is the main consumer of pigments – it uses pigments as fillers and as paper coatings. Filler and coating pigments are noticeably cheaper than wood fiber and binders, so they generate considerable cost savings. They also impart desired properties to paper, such as brightness and gloss. The use of pigments in plastics production has increased significantly. In Asia, the plastics industry ranks alongside paper manufacturing as a major consumer of pigments.
Solutions for each stage of production
Pigment usage has a long value chain: it starts at the mine and continues through production facilities to the final product. The principal white pigment products are ground and precipitated calcium carbonate and kaolin clay.
The raw materials for white pigment products occur in the ground as chalk, limestone, marble or kaolin clay. At the beginning of the production chain, the mineral is extracted and crushed into smaller particles and washed or cleaned before the production process.
The pigments can be ground, calcined, precipitated or dried, depending on the product and the required properties. The end use is determined by the type of pigment and its properties, such as particle size, which can vary from a coarse to an ultra-fine granule. Pigment products are formulated into slurry or dry products, and they are transported in the selected form to the end user, such as paper or plastics manufacturers.
“Kemira provides solutions for each stage of the production process. Our chemicals can be used in the mineral purification and grinding process, where they affect the properties of the pigment slurry and process conditions, thus enhancing production efficiency,”
Savolainen recounts.
“When pigment products are manufactured as a slurry, a dispersant is used to maintain its homogeneity, and the pigment particles do not settle. The solids content of the dispersion is raised as high as possible, thus minimizing the amount of water transported with the product. This reduces transportation costs. Biocides ensure the microbiological purity of pigment slurries during production and product storage.”
Water treatment is an integral part of the entire pigment production process, and the separation and purification of the water that enters and exits the process is one of Kemira’s specialties.
Text: Hasse Härkönen
Original article is published in Kemira’s stakeholder magazine Just Add 2/2009.