Search for dissertations about: "Metals in pulp"

Showing result 1 - 5 of 27 swedish dissertations containing the words Metals in pulp.

2. 1. Storage of Hydrogen Peroxide Bleached Mechanical Pulp : Reduction in Reflectance over the Visible Spectrum

   Author : Sofia Enberg; Per Engstrand; Magnus Paulsson; Mats Rundlöf; Patrik Axelsson; Øyvind Eriksen; Yonghao Ni; Mittuniversitetet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Abstract : The objective of this thesis is to determine possible causes of the darkening of hydrogen peroxide bleached mechanical pulp over the visible spectrum and their relative contributions. It focuses on both process conditions and the composition of the pulp and the dilution water, including additions or losses of material along the process line from the bleach tower to the paper machine. READ MORE

4. 2. Dispersal and environmental impact of contaminants in organic rich, fibrous sediments of industrial origin in the Baltic Sea

   Author : Anna Apler; Ian Snowball; Karin Wiberg; Kevin Bishop; Sarah Josefsson; Lovisa Zillén; Ida-Maja Hassellöv; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Fiberbank; fiber-rich sediments; metals; persistent organic pollutants; pore water; bottom water; dispersal; sorption; pulp and paper; Natural Resources and Sustainable Development; Naturresurser och hållbar utveckling;

   Abstract : The health of the Baltic Sea is negatively affected by hazardous substances such as metals and persistent organic pollutants (POPs), which include legacy pollutants that were banned decades ago, but still circulate in the ecosystem. Elevated levels of legacy pollutants, identified by HELCOM as key hazardous substances, have been found in accumulations of fibrous sediments, so-called fiberbanks and fiber-rich sediments, which derive from old pulp mills along the Swedish north coast. READ MORE

5. 3. Influence of acid hydrogen peroxide treatment on refining energy and TMP properties

   Author : Karin Walter; Per Engstrand; Magnus Paulsson; Lennart Salmén; Mittuniversitetet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TMP; Black Spruce; Energy reduction; Hydrogen peroxide; Ferrous sulphate; Refining; Inter-stage treatment; Pulp and paper properties; Fenton´s reagent; Bleaching; Sodium dithionite; Brightness; Metals; Fibre dimensions; Cross-sectional dimensions; Chemical composition; Cellulose and paper engineering; Cellulosa- och pappersteknik;

   Abstract : The potential of using acid hydrogen peroxide under Fenton conditions to lower the electrical energy consumed during the production of Black spruce (Picea mariana) thermomechanical pulp (TMP) was investigated. The chemical system, which consisted of ferrous sulphate, hydrogen peroxide and optionally an enhancer (3,4-dimethoxybenzyl alcohol, ethylenediaminetetraacetic acid or oxalic acid/sodium oxalate), was evaluated as an inter-stage treatment where the primary refiner was used as a mixer. READ MORE

6. 4. Cellulose solutions in aqueous hydroxide bases

   Author : Beatrice Swensson; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cellulose; dissolution; NaOH; aqueous; solvent; quaternary ammonium hydroxide;

   Abstract : Cellulose is a renewable and widely available carbohydrate polymer whose utility for mankind only increases as we move towards a circular bioeconomy. Unlike most plastics or metals, it cannot be melted, and therefore, solution processing is important. READ MORE

7. 5. Contaminated organic sediments of anthropogenic origin: impact on coastal environments

   Author : Anna Apler; Ian Snowball; Sarah Josefsson; Lovisa Zillén; Magdalena Kuchler; Jonas Gunnarsson; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Fiberbank; fiber-rich sediment; metals; persistent organic pollutants; pore water; bottom water; dispersal; sorption; pulp and paper; chemostratigraphy; Anthropocene; Natural Resources and Sustainable Development; Naturresurser och hållbar utveckling;

   Abstract : The Baltic Sea is negatively affected by legacy pollutants such as metals and persistent organic pollutants (POPs) that are known to have adverse effects on living organisms, including, humans and were banned decades ago. This thesis addresses the dispersal of these pollutants from heavily contaminated, cellulose-rich sediments of industrial origin in the Ångermanälven river estuary in northern Sweden. READ MORE