Date of Award
Bachelor of Science
Paper Science and Engineering
Dr. John Cameron
The purpose of this project was to identify sodium metaborate as a pulping chemical in semi-chemical pulping with soda ash. The experimental design included four digester cooks with 0%, 10%, 20%, and 40% addition of.the borate compound. The resulting yields were 81. 3 %, 79. 2%, 77.4 %, and 7 4. 5% respectively. Therefore, under the definition of pulping, sodium metaborate was considered a pulping chemical. The pulps were mechanically refined. The resulting screened rejects increased with increasing borate addition. Handsheets were made and tested for strength and optical properties. The tensile and mull en strengths of the handsheets increased with addition of borates up to 20%, but degradation of the bonding properties occurred at high addition levels (40%). The tear strength increased dramatically (up to 24.1%) with the addition of borates to the pulping liquor. Brightness and visual color were slightly improved. The results indicate that the sodium metaborate was an effective pulping chemical with a tendency to be selective in delignification. Further work should be performed to compare the effect of substitution against conventional non-borate pulping, and possible changes in bleached pulp quality.
Hebner, Dan, "A Study of the Use of Borates in Semi-Chemical Pulping" (1997). Paper Engineering Senior Theses. 173.