Some factors that influence fiber flocculation

The tendency of native cellulose fibers to build flocs has been investigate d concerning the effect of the suspension pH and the effects of the additio n of electrolytes, fillers and fines to cellulose fiber suspensions by meas uring the characteristic flee size in highly turbulent fiber suspensions. T he effect of the liquid viscosity in fiber suspensions, induced by the addi tion of CMC (carboxy-methylcellulose) and, in a second investigation, by th e addition of saccharose (crystalline sugar) was examined. The influence of the suspension temperature on the flocculation process was also studied in order to clarify how the temperature/viscosity relationship influences fib er-based systems with regard to real papermaking conditions. These studies were conducted prior to the addition of typical wet-end chemicals. The results showed that the addition of electrolytes, fines and filler part icles, in accordance with normal papermaking practice, leads to no signific ant decrease in flee size. On the other hand, an increase in the viscosity of the environment leads to a remarkable decrease in fiber flee size by red ucing the turbulence level in the flowing suspension. The effect is more ap parent in the first stages of a viscosity increase and declines gradually w ith a further increase in viscosity.