A test of the flotation rate constant vs. bubble surface area flux relationship

摘要

The effect of gas dispersion parameters on the collection zone flotation rate constant (K_c) was investigated in a laboratory and pilot column used for de-inking of recycled paper. Operating with approximately zero froth depth, gas holdup (ε_g), superficial gas velocity (J_g) and ink recovery as a function of retention time (controlled by underflow rate) were measured. Bubble size (d_b), controlled by porosity of rigid spargers, was estimated using drift flux analysis and bubble surface area flux (S_b) calculated. From a mixing model of the collection zone, K_c was estimated from the recovery ― time data. The rate constant was not related to J_g or d_b but a linear trend was found against ε _g and S_b. These findings support the current model of the flotation pulp zone, namely K_c α S_b, but also provide further evidence that a linear dependence on ε_g can be substituted.