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Inorganic Polymers
Published in Charles E. Carraher, Carraher's Polymer Chemistry, 2017
Vycor, or 96% silicon glass, is made using silicon and boron oxide. Initially the alkali–borosilicate mixture is melted and shaped using conventional procedures. The article is then heat treated, resulting in the formation of two separate phases—one that is high in alkalis and boron oxide, and the other containing 96% silica and 3% boron oxide. The alkali–boron oxide phase is soluble in strong acids and is leached away by immersion in hot acid. The remaining silica–boron oxide phase is quite porous. The porous glass is again heated to about 1200°C, resulting in a 14% shrinkage due to the remaining portions filling the porous voids. The best variety is “crystal” clear and is called fused quartz. The 96% silica glasses are more stable and exhibit higher-melting points (1500°C) than soda-lime glass. Crucibles, ultraviolet filters, range burner plates, induction furnace linings, optically clear filters and cells, and superheat-resistant laboratory glassware are often 96% silicon glass.
Recovery of Palladium by Extraction-electrodeposition Using N, N, N’, N’, N”, N”- Hexaoctyl-nitrilotriacetamide
Published in Solvent Extraction and Ion Exchange, 2022
Ryoma Kinoshita, Masahiko Matsumiya, Yuji Sasaki
To evaluate the repeatable use of the NTAamide(C8)/AP system, a recycling run consisting of extraction-electrodeposition for the 5th cycle was carried out (Figure 2). For SX, a metal concentration 10-fold higher than that used in the ED evaluation (i.e., 5.0 × 10−2 mol dm−3 [PdCl4]2-) was employed in the aqueous phase to control the deposition potential related to the increase in the Pd(II) concentration. The volume ratio of the organic phase to the aqueous phase was maintained at 3.0. Thus, a high volume ratio led to the enrichment of the extracted Pd(II) complex in the organic phase. Subsequently, electrodeposition from the extracted Pd(II) complex in the NTAamide(C8)/AP system was carried out using a three-electrode system under an Ar atmosphere. A Ni substrate (99.96%, Nilaco Corp.) was used as the working electrode. A platinum wire with an inner diameter of 0.5 mm was used as the QRE. The counter electrode was separated by a Vycor glass filter at the bottom to prevent diffusion of the decomposition products from the anode compartment to the electrolyte. A constant overpotential at −2.0 V against QRE was applied to the cathode during ED.
Redox Behavior of Moisture in LiCl-KCl Eutectic Melts: A Cyclic Voltammetry Study
Published in Nuclear Technology, 2021
Litun Swain, Suddhasattwa Ghosh, Gurudas Pakhui, Bandi Prabhakara Reddy
According to the Li-Al phase diagram reviewed by McAlister,43 the Li-Al alloy with 39 at. % Li chosen by Melendres et al. lies in the + phase field, where is face-centered cubic phase based on solid Al and is AlLi (NaTl-type structure) phase with a compositional range of 45 to 55 at. % Li. Sakamura et al.44 also carried out investigations on the measurement of the equilibrium potential of PuPu couple in LiCl-KCl-PuCl3 melt where the AgAg reference electrode was calibrated against the Li-Al electrode with 42 at. % Li, which also lies in the + phase field. The temperature dependence of the AgAg electrode with Pyrex and Vycor sheath is given by the following expressions:
Thermochemical Evaluation of Standard Electrode Potential and Gibbs Energy of Formation of PuCl3 in LiCl-KCl Eutectic Melt
Published in Nuclear Technology, 2020
Suddhasattwa Ghosh, Gurudas Pakhui, S. Suganthi, S. Nedumaran, M. Kakkum Perumal, Manish Chandra, P. Venkatesh, Bandi Prabhakara Reddy
Sakamura et al. studied the thermodynamics of plutonium and americium distribution between LiCl-KCl eutectic melt and cadmium to estimate the activity coefficient of plutonium in cadmium and the separation factor of americium relative to plutonium.28 For electrochemical measurements, = 3.90 10 was chosen as the composition of the reference electrode and was calibrated against Li-Al electrode before emf measurements. The authors used both Pyrex and Vycor sheaths for the AgAg reference electrodes. The former was used for estimating and the latter was used for distribution experiments. Potential temperature relationship for both types of reference electrodes were given by