The second photograph displays the addition of 3 M sodium hydroxide. The third photograph shows the centrifuge tube after shaking and allowing the solids to settle. These results indicate that with minimal mixing in the evaporator pot the neutralization will occur very smoothly. Karraker previously measured the settling rates of sodium diuranate solids and determined particle sizes. This information proves useful for determining equipment needs for removing the uranium solids from the Evaporator pot.
Additional information comes from rheological testing.
Figure 5 contains a plot of the rheometer data for the neutralized sample. We obtained the lower set of data while increasing the shear rate and the upper data set while decreasing the shear rate. The offset indicates some hysteresis. We fit the data to a Bingham model. The Bingham model is a linear model in which the slope reveals the viscosity.