An SPS-RS Technique for the Fabrication of SrMoO4 Powellite Mineral-like Ceramics for 90Sr Immobilization

• Published in: Materials Vol. 16; no. 17; p. 5838
• Main Authors: Belov, Anton A., Shichalin, Oleg O., Papynov, Evgeniy K., Buravlev, Igor Yu, Portnyagin, Arseniy S., Azon, Semen A., Fedorets, Alexander N., Vornovskikh, Anastasia A., Kolodeznikov, Erhan S., Gridasova, Ekaterina A., Pogodaev, Anton, Kondrikov, Nikolay B., Shi, Yun, Tananaev, Ivan G.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 25.08.2023; MDPI
• Subjects: Ceramics; Compressive strength; Diamond pyramid hardness; Dilatometry; Dynamic structural analysis; Gas detectors; Graphite; Heat; Immobilization; In situ leaching; Leaching; Molybdenum; Particle size; Plasma sintering; powellite; radioactive waste management; Radioactive waste processing; Radioisotopes; radionuclides; Reagents; Scanning electron microscopy; Silicon carbide; Sintering (powder metallurgy); Solid phases; solid-phase synthesis; Spark plasma sintering; Specific gravity; Strontium 90; strontium molybdate; Waste disposal; United States > US; Germany
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16175838

This paper reports a method for the fabrication of mineral-like SrMoO4 ceramics with a powellite structure, which is promising for the immobilization of the high-energy 90Sr radioisotope. The reported method is based on the solid-phase “in situ” interaction between SrO and MoO3 oxides initiated under spark plasma sintering (SPS) conditions. Dilatometry, XRD, SEM, and EDX methods were used to investigate the consolidation dynamics, phase formation, and structural changes in the reactive powder blend and sintered ceramics. The temperature conditions for SrMoO4 formation under SPS were determined, yielding ceramics with a relative density of 84.0–96.3%, Vickers microhardness of 157–295 HV, and compressive strength of 54–331 MPa. Ceramic samples demonstrate a low Sr leaching rate of 10−6 g/cm2·day, indicating a rather high hydrolytic stability and meeting the requirements of GOST R 50926-96 imposed on solid radioactive wastes. The results presented here show a wide range of prospects for the application of ceramic matrixes with the mineral-like composition studied here to radioactive waste processing and radioisotope manufacturing.