Novel Flotation Deinking Chemistry to Remove Flexo Inks - 30 TPD Pilot Plant Results, 1998 Recycling Symposium Proceedings

Current recycling processes typically incorporate aa3 ggressive washing stages to successfully remove flexographic or “flexo” inks. The yield losses associated with such washing stages are often economically unacceptable. A goal for many old newsprint (ONP) deinking mills is to be able to efficiently deink ONP containing varying. moderate levels of flexo inks in the flotation deinking stage. Deinking systems utilizing only flotation cannot handle more than 3 -5% flexo ONP content. This paper discusses two flexo flotation deinking trials utilizing a novel organoclay chemistry in a 30 ton per day continuous process pilot plant. Flexo ONP content was 25 and 30% in each of the two trial runs. The trials were performed with closed thickener filtrate loops without process water clarification. Brightness exceeded 60 points at the end of the process that involved pre-dispersion flotation, conventional dispersion peroxide bleaching, post-flotation. and thickening.