Date of Award

4-1980

Degree Name

Bachelor of Science

Department

Pulp and Paper Technology

Abstract

In recirculating whitewater in a closed water system, the solids will increase leading to operational problems such as corrosion, scale, reduced drainage rates, reduced wire life, increased temperatures, felt plugging, foam, and dirt. In dealing with these problems, whitewater samples from a conventional seven vat cylinder board machine were tested for chemical composition. The machine operates on a closed water loop and produces approximately 250 tons per day recycled boxboard. Tested anions included chloride, silica, phosphates, nitrates, sulfate, sulfide and tannin-lignin. Cations analyzed included calcium, barium, iron, aluminum and copper. Tests were conducted over an eighteen day machine running period to determine trends in concentration levels. It was found that the anionic character of the whitewater was increasing while the cationic character tended to decrease. Indirectly board caliper could have played a role in controlling ion concentration by a filtering mechanism. The large increase in tannin-lignin concentrations are believed to increase the anionic colloidal properties and thus increase the cationic demand of the water. This behavior may in fact activate corrosion of cationic metal pipes used for water transport.

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