Hydrosol: A new process for deinking old newsprint

Old newsprint (ONP) stored for more than 6 months after printing is often considered difficult to deink using conventional methods. In order to remove this over-aged ONP ink, Kuldeep K. Kaul developed a composition that uses water, soaps, and an immiscible organic solvent to de-ink ONP under prescribed process conditions without further bleaching. It is close to the base paper fiber slurry. The hydrosol deinking process adopts near-neutral pH, the final whiteness of the slurry reaches 61.7% GE, and the anionic surfactants such as sodium dodecylbenzenesulfonate and sodium lauryl sulfate are used. The unique effects of cationic surfactants such as N-hexadecyl-NNN triammonium bromide, and water-immiscible organic solvents, have been successfully applied to ONP deinking after printing for up to 3 years and can be decanted Analytical methods recover organic solvents for recycling. This new hydrosol deinking process is also suitable for the deinking of other waste papers such as copy papers and stale magazine papers containing stickies.