A study on the Properties ofLocaIONP/OMG Deinked Pulp in Comparison With Local CMP Pulp

Randomized samples have been prepared from local Old Newspaper (ONP) and Magazine
(OMG) with their specified mixtures having been repulped, deinked and subsequently
bleached with hydrogen peroxide. Three levels of paper mix (100, 70/30 and 50150 percent
of ONP/OMG), 2 types of chelating agent (DTPA, EDTA), and 3 levels of calcium ions
(1,1.5 and 2%) have been studied as variable parameters. Brightness values of the deinked
pulps, before and after bleaching, and optical and mechanical properties of bleached deinked
pulps have been measured and compared with local hardwood CMP pulp.
The results have shown that although the brightness ofCMP pulp is higher but its mechanical
properties are lower than deinked pulp at similar freeness. Normalization results have shown
that the deinking treatment using 50150 ONP/OMG, EDTA and 1% calcium ion charge won
the highest score or the best optical - mechanical properties as compared to local hardwood
CMP pulps. As a result , it can be predicted that the bleached deinked pulp prepared under
optimum conditions as indicated in this research, can be used as a mixture furnish with local
CMP for making newsprint paper.