Everything starts in the 30m3 pulper, with the introduction of water and cellulose bales.
Paper production comprises a number of phases, beginning with cellulose pulp extracted from wood – itself the result of a complex process.
Using a high-speed impeller, the pulper hydrates and breaks down the fibres, producing a suspension at a final density varying from 4% to 13%.
Over time, the practice of loading paper with finely powdered mineral fillers has become more common. This improves the printing properties of the finished product by:
- Improving opacity.
- Decreasing transparency.
- Improving receptivity to ink.
- Facilitating forming of the sheet, determining its grammage.
Calcium carbonate: a delicate and determining factor.
Calcium carbonate is among the most common of these substances: a very fine powder with a very high specific weight. With the right know-how and technology, it can be stored in different kinds of silos, including internal polyester silos.
The carbonate is then transferred, usually via mechanical auger transports, to a vat where the slurry – a 2-30% suspension of calcium carbonate in water – is prepared. Transfer pumps then add this suspension to the cellulose in the pulper.
The slurry, together with kaolin, hydrogen peroxide and various other minerals, is stored in vats equipped with agitators. It is also used in the coating phase to increase gloss and improve printing properties.
The main players in the Italian paper industry turn to Technosilos to support the efficient management of calcium carbonate.
Starch: a versatile polysaccharide.
Starch is another ingredient widely used in the production of paper and cardboard from storage all the way through to the preparation vats. A naturally biodegradable polymer, it can be managed every step of the way by Technosilos systems.