OPTIMIZATION OF FLOTATION PARAMETERS IN OLD BOOK PAPER DEINKING

The effect of flotation parameters such as flotation consistency, temperature, flotation time, air to pulp ratio, turbulence level (velocity of pulp flow), and pH on domestic old book paper deinking efficiency was studied by using a high-consistency laboratory pulper and a laboratory deinking cell developed by ourselves. The optimized flotation conditions are: flotation consistency 1.2%, 50℃, 6 min, air to pulp ratio 40%, velocity of pulp flow 5.0m•s^(-1) and pH 11.0. By using the optimized flotation conditions, the flotation deinking pulp brightness can reach 77.01% ISO, 9.69% ISO higher than that of the control, the effective residual ink concentration is 175.26 mg•kg^(-1), which less than 437.84 mg•kg^(-1) of the control, deinking efficiency is up to 59.97%.