Volume 4, Number 2
May 1991

Breakthrough in Deinking

Mills that have hesitated, because of market uncertainties, to invest in deinking and other equipment for recycling are probably glad that they waited, because now they have a third option for separating ink and toner from fiber, in addition to washing and flotation: steam explosion.

The 17-year old process was only recently applied to the paper industry. Waste paper is shredded, compressed (400 psi) and heated (450°F) in a steam digester, held in the digester one to four minutes, and released by explosion. Only minimal cleaning and screening is necessary. In fact. the ink particulates are so small that they are invisible to the eye, but they can be washed out with plain water if higher brightness is desired.

The advantages of the steam explosion process are impressive. It uses 30% less energy than conventional recycling equipment; no surfactants or chemicals are necessary; the plant can be set up and running in six months as opposed to two years; and fewer production steps are necessary (10 steps for old newspapers and magazines, as opposed to 21). Types of waste paper that cannot be satisfactorily handled by conventional equipment, such as computer printouts and UV or laser printing, do fine in steam explosion facilities. Capital requirements are lower.

Recoupe Recycling Technologies, a new company formed last October, is essentially a partnership between Stake Technology Ltd. and Chesapeake Corp. The idea of using the technology in the recycled paper business came from a group of Chesapeake employees who had been asked by the CEO to look into emerging technologies, and knew it was beginning to be used to pulp wood. First large scale trials were held at the University of Sherbrooke in Quebec last July, using bales of shredded old corrugated cartons, coated paper and office waste. Recoupe plans to have a pilot plant in a year, and StakeTech is building its own pulp mill in Quebec using the steam explosion process. (Condensed from a story in American Papermaker, March 1991)