Pulp & Paper 

There are 2 main types of chemical pulps, Sulphite and Kraft, with the latter being by far the most predominant. Sulphite pulps are easily bleached to full brightness with hydrogen peroxide and oxygen in one or two stages. Kraft pulps are more difficult to bleach to full brightness requiring 3-5 bleaching stages depending on the type of wood, softwood or hardwood.

SOCAL^® improves the opacity of papers by increasing the light scattering coefficient of the filled paper by controlling the specific crystal shape (calcitic scalenohedral) and the particular and well defined dimensions of the single crystal to values below 0.3 microns.

The use of hydrogen peroxide, in combination with caustic soda, is a well established method for bleaching mechanical pulps. Bleaching with hydrogen peroxide achieves high, stable brightness and helps to improve strength as well as optical properties, whilst maintaining high yield.

In the alkaline peroxide mechanical pulping process (APMP) Hydrogen peroxide is used together with caustic soda in the impregnation stage. This treatment of wood chips softens the lignin and gives a higher brightness in the refining step. Alkaline peroxide mechanical pulping has become an increasingly popular alternative to the sulfite chemicals in the production of chemimechanical pulp.

Three types of processes are used to recycle waste paper: flotation deinking, ink dispersion and washing deinking. Hydrogen peroxide is used in all of these processes.

There is a need to disinfect white water systems of paper machines to prevent microbial contamination of fibrous material in the circulation water. Peracetic acid has been proved to be extremely effective against a broad spectrum of microorganisms. Moreover it operates over a wide temperature range, removes biofilms, controls odours and removes sulphides.