State-Of-The-Art for Paper Recycling

Abstract. As the demand for materials continues to grow and the supply of natural resources continues to dwindle, recycling of materials has become more important in order to ensure sustainability. However, many materials can only be recycled a limited number of times due to physical degradation (paper and board), chemical degradation (plastics), or the presence of impurities (metals). This paper presents a review of solid recycling, focusing on the technology for paper recycling. It describes studies on pulp and paper recycling in five problem areas: paper and fiber sorting technologies, deinking and contaminant removal, pulp bleaching technologies, restoration of papermaking properties of recycled fibers, and performance characteristics of recycled paper. During the past two decades, numerous studies have been conducted on the potential of papermaking from recycled fibers. Most studies have shown that the strength properties of fibers and paper are reduced upon recycling. Recycled pulp is an important component of many paper products. Over 50 grades of waste paper have been identified. As a result, most waste paper has to be sorted, graded and baled before going to paper mills. The quality of the waste determines the end quality of the recycled paper. Mixing all these different type of quality paper will reduce the purity of the highest quality fibre. The recovered paper may contain fibers which may have been recycled once, twice, or perhaps several times. Wood fibers can only be recycled five to seven times before they become too short and brittle to be made into new paper. Previous studies showed two basic approaches to improve the properties of recycled pulp. In summary, the effect of recycling on pulp strength properties is a complicated process