Fiber Recovery from Waste Paper: A Breakthrough in Re-Pulping Technology, 2003 Fall Technical Conference

Paper mills and converters produce large quantities of waste paper. Paper trim from the process, roll ends, offquality product and overruns are all sources of waste. Where feasible, process scraps are re-pulped and blended back into the feedstock. Converting paper to its final product sometimes produces wastes that are difficult if not impossible to re-pulp with conventional technology. For example, many paper products are laminated with plastic. Many mills either process laminated waste paper into pellets for boiler fuel or pay to have the wastes land filled. This paper describes a new technology that cost-effectively recovers quality fiber from papers currently being sent to landfill.

Fiber Recycling Technologies, Inc. (FRT) has developed a low-energy, mechanical re-pulping method that gently separates fibers while leaving contaminants largely whole, so that fiber can be readily screened from contaminants. Trials were run on a range of recovered papers and landfill waste, including poly-laminated paper trimmings, multi-laminated food packaging, and unsorted municipal solid waste. Success from the trials encouraged FRT to start a commercial re-pulping operation using their own technology.

Recovered papers can use considerably less energy in pulping than wood-based pulp, so making secondary fibers competitive with virgin ones can save significant energy. A 20-ton per day FRT pulper operating commercially annually saves about 7,000 tons of waste fiber from being land filled, and requires 11 to 30 kWh per ton for pulping. By comparison, refiner-mechanical pulping of virgin wood requires about 1,972 kWh per ton (Martin, N., et al 2000). Other mechanical and kraft pulping processes have similar or greater energy intensities.