Some factors influencing flexo ink calcium soap particle morphology in flotation deinking

The reaction between CaCl2 and various types of fatty acids soaps is studied focusing on calcium ion concentration dependence on the homocoagulation of flexo ink. Result show that at low ion concentration, the ink formed loose irregular particles, whereas at higher calcium ion concentration dense, spherical ink aggregates are formed. The reaction between the dispersed ink (flexo ink) and pre-made calcium soap particles is studied. The deposition of flexo ink on the calcium soap particles is found to very dependent on the free calcium ion concentration in solution at 50°C. At low ion calcium concentrations (< 1 mM), flexo ink does not deposit onto the calcium soap particles, whereas at calcium concentrations between 1.5 and 4.4 mM, several different aggregation processes occur in the mixture. The structure varies from small aggregates of flexo ink and calcium soap particles.