STUDIES ON DEINKABILITY FACTORS OF OLD NEWSPRINTS BY USING DIFFERENT SURFACTANTS AND PROCESS VARIABLES

Abstract

Optimizations of chemical dosage and flotation time have been attempted in flotation deinking process by using old newsprints (Hindustan Times) on the basis of Deinkability Factor based on ISO Brightness and ERIC value. From the experimental results, it is shown that 10 minutes flotation time is sufficient for ink removal. The optimum chemical dosage for oleic, palmitic and triton x 100 is 1.2% and optimum chemical dosage for stearic acid is 1.0%. Stearic acid gives better strength properties as compared to oleic, palmitic and triton x 100. It appears that beyond 10 minutes flotation time that removal of ink is not significant. The rpm of rotor of flotation cell or indirectly the air flow rate should be maximum to have maximum flotation efficiency. It is found that 2000 rpm gives maximum flotation efficiency. Consistency of flotation should be 1% to have great probability of ink particles attachment due to their high concentration. Effects of chemical dosages and flotation time, on Deinkability Factor based on ISO Brightness and ERIC Value in the flotation deinking process have been studied using fatty acids and surfactants namely oleic acid, palmitic acid, stearic acid and triton x 100. From the experimental data it is observed that Deinkability factor increases with increase in chemical dosages up to the optimum condition. Beyond the optimum chemical dosage the agglomerate size increases to a limit, where the ink agglomerates remain back in the system, leading to lower Deinkability Factor.