Effect of Al and Fe sources on conversion of high-level nuclear waste feed to glass

Melting behaviour of simulated radioactive waste as functions of different redox iron-bearing raw materials

“…6 shows the phases identified and quantified by Rietveld refinement for each of these samples, as well as the amorphous phase fraction. Quartz dissolution is similar in both feeds and compares with the previous measurements of quartz [59] . At 1150 °C the quartz has completely dissolved in both feeds.…”

“…The viscosity of the feed containing Fe(OH) 3 was an order of magnitude greater than the viscosities of any of the other feeds tested, it was concluded that the feed viscosity likely influenced the rate of melting [58] . Marcial et al observed a correlation among these measured rates of melting and the fractions of chemically-bound water contributed by the iron sources, potentially leading to reduced melt viscosity and more rapid silica dissolution [59] . 57 Fe Mössbauer spectroscopy of the final vitrified glass products showed very little difference in the iron redox ratio, Fe 3 + / Fe, between glasses made with the different iron-bearing raw materials when melted in air at 1150 °C.…”

Cold‐cap structure in a slurry‐fed electric melter

“…For this reason, we have adopted the fraction of dissolved silica as a measure of the conversion degree 16 (see Section 3.3). Experimental data indicate that the small fraction of silica that survives the passage through the cold cap and enters the melt below 35,69,70 is virtually independent of the temperature history of the feed particle inside the cold cap. 20 This allows a definition of T B as the temperature at which the undissolved silica drops to a certain value at the cold-cap bottom.…”

Alternative Reductants for Foam Control During Vitrification of High-Iron High Level Waste (Hlw) Feeds

“…The coke used in the sample is ~93.3 wt% C according to x-ray fluorescence (XRF), with 3.1 wt% O, 1.1 wt% Si, 0.8 wt% Al, 0.6 wt% Fe, 0.4 wt% S, 0.3 wt% Ca, 0.1 wt% Mg and 0.1 wt% Ti, with trace amounts of P, Na, Cl, Ba, Sr, Mn, Cr, Ru and Ni. The mechanisms of foam expansion and collapse are determined by the quantity of gas evolution, the temperature of gas evolution and the viscosity of the melt at the temperatures of gas evolution [6,37,38]. The secondary foam, caused by SO 2 and O 2 evolution is less significant than the residual CO 2 contributing to the primary foam for most feeds.…”