[en] Zircon is an important industrial mineral and apart from its own applications, serves as the primary raw material for the production of a series of technologically significant zirconium and hafnium chemicals. However, due to its high melting point and chemical inertness, processing of zircon is a major technological challenge and very aggressive methods have to be adopted to open up zircon. This paper will review some these methods and attempt to determine the trends in the processing of zircon. Along with some of the other techniques, the carbo-chlorination of zircon in an electro-thermal fluidized bed reactor, which constituted a part of the pyro-chemical process for preparing nuclear grade zirconium, was extensively investigated in our laboratory. The technological challenges and the environmental and economic benefits of this technique vis-a-vis the other established practices will be discussed, with emphasis on production of nuclear grade zirconium. (author)

[en] The paper discusses the essential details of metallothermy and presents an overview of the process as applied to rare earth metal and alloy (particularly Sm-Co) production technology. The paper also highlights the major advantages of metallothermy over the conventional melting and casting processes. 15 refs. (author)

[en] The major use of cobalt metal continues to be in super alloys followed by its use in hard materials, pigments, magnets, batteries, orthopedic alloys, catalysts and coloring agents, etc. Besides this, extensive usage of its radioisotope ⁶⁰Co, as a Gamma radiation source for a variety of industrial and medical applications, Self Powered Neutron Detectors (SPND's), flux mapping, fuel management, etc. makes it a material of immense interest for the researchers. Powder metallurgy (PM) routes are being increasingly investigated because it provides much finer microstructures with uniform distribution of micro-constituents with attractive properties. PM route is more than an option where the primary source of matrix metal of an alloy is scarce or the matrix metal has to be recovered from secondary resources. Cobalt is an example of the latter case and it is generally recovered in powder form, from various secondary resources (e.g. spent ammonia cracker catalyst, tool steel etc.) This paper reports on studies conducted on sintering of cobalt powder for radioisotope production. Cobalt powder was prepared by thermal decomposition of cobalt oxalate and reduction of cobalt sulfate using hydrazine as a reducing agent in alkaline medium. The Co powder was characterized by SEM, TEM and XRD for size, shape, phase and morphology prior to sintering. The optimum parameters for preparing and scaling up of cobalt powder with suitable morphology were established. The influence of compacting pressure and sintering temperature were studied on cobalt metal powder of different characteristics to obtain sintered density greater than 95 % theoretical. The sintered microstructures were characterized by optical microscope as well as SEM. The findings of characterization studies were utilized to adjust judiciously the process parameters like temperature, time and compaction pressure to control the grain growth during sintering. (author)

[en] Partitioning of plutonium from uranium is an important step in the reprocessing of spent fuel by PUREX process of solvent extraction using 30% TBP-dodecane. This is achieved by selectively reducing the Pu in solution to least extractable trivalent state by uranous nitrate as the reductant. The latter is conventionally produced by electrolytic reduction of uranyl ion in presence of hydrazine nitrate as uranous nitrate stabilizer using Pt-coated titanium as the anode. The anode plating wears out after period of operation thus affecting the process efficiency and hence the quality control testing of platinum plated electrode becomes important. This article describes the use of Beta backscattering method with strontium-90 radioisotope as non-destructive testing tool for measuring the coating thickness of the sample Ti electrode. The surface characteristics and coating morphology were also examined by scanning electron microscope and the micrographs are presented. (author)

[en] Reactive magnetron sputtering, a physical vapor deposition (PVD) technique, is used widely for deposition of compound and composite coatings. Ternary compound or multi component compound coatings are increasingly being researched due to their exotic properties. The properties of these coatings depend strongly on the composition of the films. A mathematical model has been developed to predict the composition of the metallic constituents of the coatings deposited by reactive magnetron sputtering using two metals composite target in the presence of a reactive gas (nitrogen) environment. In the model, composition of the metallic constituents of the coating and percentage of covered areas of the target (target poisoning) vis-a-vis partial pressure of nitrogen can be predicted. The model has been experimentally tested on titanium-niobium system. (author)

[en] The compact high temperature reactor (CHTR) is being developed to serve as a compact power pack in remote areas not connected to the electrical grid. It is a mainly ²³³U-thorium fuelled, lead-bismuth cooled and beryllium oxide moderated reactor. This reactor is being designed to operate at 1000 °C to generate about 100 kW_Th power, with a core life of 15 years and will incorporate several advanced passive safety features. The reactor also facilitate demonstration of technologies for high temperature process heat applications such as hydrogen production from water

[en] The present article highlights the developments made in the field of indigenization of the technology for preparation of cobalt shapes for radioisotope applications from a secondary resource. In the first step, the process of extraction of cobalt in the form of metal powder from a secondary indigenous resource as spent ammonia cracker catalyst is described. In the second step, the processes of conversion of cobalt metal powder into the desired shapes followed by coating over the finished products have been presented. (author)