Abstract
The current emphasis on the environment and its impact on recycling is placed into context with an introduction of how life cycle analysis and assessment techniques will play an increasing role in determining the direction of industrial development and legislation.
The review is based around the subjects identified by European Paper industry experts on recycling and recycling research as being the most critical to the long term development of the industry. These are the characterisation of the changes which occur to fibres and their surfaces on recycling; the influence of chemicals on water quality and production efficiency; the fundamentals of flotation deinking and recycling models. In addition a section on alternative uses for waste paper is included.
Recent reviews on the effects of recycling on paper properties are summarised and an explanation for the apparent anomalies and differences given. Results on post paper manufacturing treatment on recycle potential are also included.
The information on the effect of chemicals on recycling is sparse and tends to be empirical. The greatest effects are on paper strength and brightness where bleaches or brightening agents are used. The chemicals which dissolve also have a detrimental effect on process additive efficiency and add to effluent treatment and discharge costs.
The deinking section is subdivided into – a brief review of the chemistries and drying methods of inks and toners and their influence on particle size on repulping; the chemistry of the repulping process; the flotation process. The influences of chemicals on flotation and the fundamental phenomena which occur during the process are described.
Models for assessing age distribution and product properties at various levels of recycling are explored. In addition the build up of materials within a recycling loop is examined along with the energy balance of recycling compared with manufacture from virgin materials.
Alternative uses of wastepaper considered include energy generation, composting and as a raw material for a variety of applications. None of these are likely to become major uses, competitive with wastepaper used for paper and board production in the near future.
It is concluded that there are various studies of a fundamental nature which need to be completed to advance the technology of recycling. Greater emphasis on the supply side of wastepaper would also yield industrial benefit.
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