Paper & Pulp

Lewatit® ion exchange resins and Lewabrane® membranes for the paper industry

 

Water is an essential material for manufacturing paper and pulp, beginning with the pulping of the raw material all the way to its use in the giant paper machines on which cellulose fibers are separated from a suspension and drained, to the winding of the finished paper onto rolls.

For this complex, rapid process to function reliably and produce paper of a consistently high quality, the water used must also meet strict demands. In particular, the nature and volume of the dissolved contents must be kept constant with very little variation to enable different paper chemicals to work to full effect. This is why Lewatit® ion exchange resins from LANXESS are in use in paper mills around the world to ensure that optical brighteners give the paper the best degrees of whiteness by reliably removing ionic, organic compounds such as humic acids from the process water.

Lewatit® ion exchange resins and Lewabrane® membrane elements for reverse osmosis can often be combined to great effect to soften and demineralize the feed water for the process. They provide a reliable and economical means of producing the water required. The LewaPlus™ design software is capable of mapping combinations such as these to the customer’s precise requirements, thus giving the user the greatest possible reassurance of receiving the best treatment solution.

Ion exchange reins are also indispensable wherever steam is used – for heating the tanks during pulping, for example, or for drying the paper webs. As in thermal power plants, they ensure that water-steam cycles operate reliably and with little maintenance. This requires careful treatment of the make-up water, and also high-performance condensate polishing.