Returning Bleach Plant Waste to the Recovery Cycle-Effects of Chelating Agents and Increased Concentration of Magnesium and Maganese, 1996 International Pulp Bleaching Conference Proceedings
If bleaching filtrates are returned to the recovery cycle, chemicals that are charged or washed out in the bleach plant may cause process problems of various kinds. In this paper, experiments will be presented in which contamination of black, green and white liquor has been carried out deliberately. The contaminants were manganese, concentrated Q-stage filtrate and magnesium. The experiments have ranged from lab tests to full scale mill trials. The conclusion is that the chelant EDTA increases calcium content in white liquor and it may also cause manganese build-up in the lime cycle. Increased manganese content can be handled in the recovery cycle. Increased magnesium concentration disturbs green liquor clarification. However, an antidote to magnesium is demonstrated with very promising results.
Returning Bleach Plant Waste to the Recovery Cycle-Effects of Chelating Agents and Increased Concent