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Abstract
Reduced fiber rejection in flotation deinking is very important to reduce the cost of secondary fibers in paper recycling and to conserve natural resources. Online monitoring of fiber rejection is a prerequisite to achieving process control for the reduction of fiber rejection in flotation deinking. It also can improve understanding of the effects of various operating parameters on fiber rejection in flotation for process optimization. This study demonstrates in situ monitoring of wet (liquid) and solid (mainly fiber) rejections during froth flotation of waste pulp suspensions by means of conductivity measurements of the rejected froth. Laboratory flotation deinking experiments were conducted using mixed office wastepaper (MOW) supplied by a recycling paper mill. It was found that both the total wet rejection and the solid consistency in the rejection stream correlate well to the measured relative conductivity of the rejected froth. The immediate application of the conductivity technique described is to monitor wet and fiber/solid rejection in industrial flotation deinking operations.
Keywords
Electric conductivity,
pulping,
fibers,
waste paper,
recycling,
flotation,
conductivity,
wet rejection,
fiber/solid rejection,
fiber rejection loss,
wood fibers,
deinking,
flotation processes
Citation
Zhu, J. Y.; Fleischmann, M.; Gleisner, R. 2006. Froth conductivity for in situ monitoring of fiber (solid) and wet rejects in flotation deinking. Proceedings of 3rd International Symposium on Emerging Technology of Pulping and Papermaking, 2006 November 8-10, Guangzhou, China. Guangzhou, China : South China University of Technology Press, 2006. New technologies in non-wood fiber pulping and papermaking: pages 138-143.
