OPTIMIZATION OF FLOATATION DEINKING VARIABLES AND STUDY OF EFFECT OF VARIOUS DEINKING CHEMICALS

Abstract

Optimization of flotation process is attempted using ONP. Optimization of flotation time, flotation consistency, RPM of rotor of flotation cell, has been done. 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 airflow rate should be maximum to have maximum floatation efficiency It is found that 2000 RPM gives maximum flotation efficiency. Consistency of flotation should be 1.2% to have great probability of ink particles attachment due to their high concentration. Effects of surfactants in flotation deinking operation of ONP has been studied using 5 surfactants namely Triton x-100, Tween 80, Brij-35, Anmol surfactant DI and Oleic acid. It is observed that Triton x 100, Brij- 35 and oleic acid have optimum dosage after which the deinkability factor and flotation rate constant starts decreasing with increasing dosage. In case of Tween 80 and Anmol DI with the increase in their dosage, the deinkabilty factor and flotation rate constant goes on increasing resulting in better quality pulp while the loss of fines and fibers also increases. It appears that Tween 80 and Anmol DI also accumulate dust or fines along with ink to form the medium size agglomerate, which can be carried away with the air bubble as foam with the increase in dosage. The ink agglomerate size increases with increase in dosage of Triton x 100, Brij-35 and Oleic acid resulting in its reversal back to the pulp beyond optimum dosage.