SALTING-OUT PRECIPITATION OF POTASSIUM DIHYDROGEN PHOSPHATE (KDP) .2.INFLUENCE OF AGITATION INTENSITY

The influence of agitation intensity on KDP salting-out precipitation with aqueous solutions of ethanol was studied at 30 degrees C. Inducti on periods were determined as a function of supersaturation, in the ag itation intensity range 50 to 500 rpm, by a visual procedure. The indu ction periods are constant between 50 and 400 rpm, decreasing later on probably due to the decrease in the Kolmogoroff turbulence microscale , which enables the processes to occur at molecular level. The micromi xing process does not interfere with the formation of the new solid ph ase since the micromixing time contribution to the induction period is negligible. From the experimental results it was possible to conclude that the precipitation mechanism is primary nucleation followed by no rmal growth, in all the agitation intensity range studied. The interfa cial surface tension does not depend on the agitation intensity.