Investigation on Recycling of printed mechanical papers and the effects of its blending with CMP pulp in production of printing paper

In this study, recycling of printed mechanical papers and its blending with CMP pulp from Mazandaran Wood and Paper Mill was investigated in production of printing paper. On the basis of deinking experiments, the optimum conditions were determinde as following:
- Sodium hydroxide: 2% on the basis of o.d. weight of fibers
- Hydrogen Peroxide: %1/5 on the basis of o.d. weight of fibers
- Pulping time: 10 min.
- Pulping temperature: 65 ° c
The results of deinking experiments showed that not only chemicals, but temperature and time of pulping directly influences the brightness of deinked pulp.Therefore,increasing temperature or time of pulping or both,increases the brightness of deinked pulp.In addition, the results of physical, optical and mechanical strength tests of handsheets made from pulp samples, indicated that recycled mechanical waste paper can be substituted with some portion of CMP in production of printing paper.The optimum combination was found at %45 CMP, %30 WCP and %25 L.F.