Given: ACETONE=0.0123 gm/cm.s H2O=0.01 gm/cm.s ACETONE=0.80 gm/cm3 Au=19.31 gm/cm3 SiO2=2.65 gm/cm3 SnO2=6.09 gm/cm3 PbS=7.5 gm/cm3

1. An aqueous suspension of cassiterite (SnO2), galena (PbS) and gold (Au) spheres is poured and thoroughly mixed into a cylindrical vessel and allowed to settle. The original suspension contains 10 wt% each of all three components. Particle diameters are 5 micron cassiterite, 25 micron galena and 250 micron gold. The vessel is 200 cm high. The solids are initially completely dispersed throughout the vessel. After settling for one hour, what is the weight fraction of cassiterite to galena to gold in the sediment at the bottom of the vessel? Assume the particles reach a terminal settling velocity instantaneously after being placed in suspension.

2. A suspension of quartz and gold is mixed and poured into an elutriator containing acetone. Assume that the mixture is originally homogeneously dispersed through the volume of the elutriator. The original suspension contains 5 wt% each of 5 micron quartz and 15 micron gold spheres. The elutriator is 90 cm high. Assume the particles reach a terminal settling velocity instantaneously after placed in the elutriator. The upward flow of acetone in the elutriator is 1 x 10-3 cm/sec. At what time is 50 wt% of the quartz left in the elutriator? What is the minimum acetone flow velocity of acetone that would cause 100% of all solids to report to the overflow?

Given: P(ACETONE)=0.80 gm/cm3 U(ACETONE)=0.0123 gm/cms P(Au)=19.31 gm/cm3 P(SnO2=6.09 gm/cm3 U(H20)=0.01 gm/cms P(SiO2)=2.65 gm/cm3 P(Pbs)=7.5 gm/cm3 1. An aqueous suspension of cassiterite (SnO2), galena (PbS) and gold (Au) spheres is poured and thoroughly mixed into a cylindrical vessel and allowed to settle. The original suspension contains 10 wt% each of all three components. Particle diameters are 5 micron cassiterite, 25 micron galena and 250 micron gold. The vessel is 200 cm high. The solids are initially completely dispersed throughout the vessel. After settling for one hour, what is the weight fraction of cassiterite to galena to gold in the sediment at the bottom of the vessel? Assume the particles reach a terminal settling velocity instantaneously after being placed in suspension. 2. A suspension of quartz and gold is mixed and poured into an elutriator containing acetone. Assume that the mixture is originally homogeneously dispersed through the volume of the elutriator. The original suspension contains 5 wt% each of 5 micron quartz and 15 micron gold spheres. The elutriator is 90 cm high. Assume the particles reach a terminal settling velocity instantaneously after placed in the elutriator. The upward flow of acetone in the elutriator is 1 x 10 cm/sec. At what time is 50 wt% of the quartz left in the elutriator? What is the minimum acetone flow velocity of acetone that would cause 100% of all solids to report to the overflow? overflow 90 cm underflow acetone flow