Study Removal And Mechansim Of Contaminants In Recycled Paper Under Neutrale Conditions

After years’development, the deinking technology has been very mature. Althoughneutral deinking and enzymatic deinking were researched, they couldn’t be applied infactories because of many reasons. As for newspaper mills, its deinking technology uses lowalkali dosage, so weakly alkaline technology will be the next development direction. As forwhite cardboard factory, it still uses high alkali dosage, so using lower alkaline dosagetechnology will be the next development direction.We first measured surface tension and contact angel in different chemical systems,studied its interaction with different pulper conditions. We found that the trend of surfacetension and contact angel first increased then decreased with the increase of temperature. Alsothe trend of surface tension and contact angel went down, then went up with the increase ofNaOH amount. And the trend of surface tension and contact angel has different change trendwith the increase of H2O2and Na2SiO3amount.Then we studied the influence of different chemicals on the removal of ink and stickiesin the ONP pulp under weakly alkaline condition, and contrast with deinking effects underalkaline conditions by using a factory mature produnctive technology. The results showed thatNa2SiO3had better deinking efficiency than Na2SO3in the pulp progress. when Na2SiO3amount was2%, the removal efficiency of stickies was the best. Na2SiO3and Na2SO3haddifferent function stage when they were used in deinking process, Na2SiO3acted on pulpingprocess while Na2SO3acted on floating process.We also studied the influence of different pulper conditions on the removal of ink andstickies in the OMG pulp, and also measured surface tension and contact angel in differentchemical systems, studied its interaction with old books’ deinking effect. We found that thetrend of brightness increment and ERIC removal quantity decreased with the increase ofcontact angel, lower contact angel was good for deinking effect. Also the trend of brightnessincrement and ERIC removal quantity went up, then went down and went up with the increaseof surface tension. Lower and higher surface tension was good for deinking effect.We also studied the influence of four deinking agents from factories on the removal ofdeinking effect in the OMG pulp by using one factory deinking productive technology. The results showed that the323deinking agent has the worst deinking effect. In the floatingprocess, the brightness was improved best by fanya-s deinking agent, the ink removing effectwas improved best by luodiya agent, the stickies removing effect was improved best byDIA-30agent. The brightness and ink removing effect and stickies removing effect wasimproved best by DIA-30agent in the washing process. So the DIA-30agent has the bestdeinking effect.