The motion of liquid metal droplets in molten slags was studied using
low temperature physical modeling and X-ray observations at high tempe
ratures. Experiments were done to assess settling times of metal dropl
ets in slags. Experimental work included oil and water modeling and hi
gh temperature experiments utilizing a furnace equipped with an X-ray
fluoroscopy apparatus. Results show that settling times of metal dropl
ets in stagnant slags and water droplets in a variety of oils can be a
ccurately predicted utilizing Stokes' equation modified for the approp
riate experimental conditions. It was also found that gas stirring in
slags, whether by chemical reaction or gas injection, and slag foaming
increases droplet settling times. Stable foams resulting from the rea
ction of FeO in the slag and carbon in the metal as well as gas inject
ion in the metal phase caused rafts to form which could permanently ho
ld droplets up to about 5 mm in diameter at the top of the slag. For b
etter separation, slags with low viscosities are recommended and foami
ng should be avoided.