Hydrothermal Synthesis of Delafossite-Type Oxides

The syntheses of copper and silver delafossite-type oxides from their constituent binary metal oxides, oxide hydroxides and hydroxides, by low temperature (<210 °C) and low pressure (<20 atm) hydrothermal reactions are described. Particular emphasis is placed on how the acid-base character of a constituent oxide determines its solubility and therefore whether a particular delafossite-type oxide can be synthesized, a strategy utilized by geologists and mineralogists to understand the conditions necessary for the synthesis of various minerals. Thus, the geochemical and corrosion science literature are shown to be useful in understanding the reaction conditions required for the syntheses of delafossite-type oxides and the relationship between reactant metal oxide acid-base character, solubility, aqueous speciation, and product formation. Manipulation of the key parameters, temperature, pressure, pH, and reactant solubility, results in broad families of phase-pure delafossite-type oxides in moderate to high yields for copper, CuBO2 (B) Al, Sc, Cr, Mn, Fe, Co, Ga, and Rh), and silver, AgBO2 (B ) Al, Sc, Fe, Co, Ni, Ga, Rh, In, and Tl)

Experimental activities on stratification and mixing of a gas mixture under the conditions of a severe accident with intervention of mitigating measures performed in the ERCOSAM-SAMARA project

International audienceThe ERCOSAM-SAMARA project is based on severe accident scenarios involving large amounts of hydrogen leading to explosive atmospheres. A generic scenario was scaled down according to the facilities involved in the project TOSQAN from IRSN, SPOT from JSC Afrikantov OKBM, MISTRA from CEA and PANDA from PSI. Each scenario is divided into two sequences. The first one is dedicated to the establishment of the hydrogen explosive atmosphere. The second one consists in the impacts of different mitigation means namely spray, cooler or thermal effects of passive auto-catalytic recombiner (Heater device). Tests dedicated to spray system were not performed in SPOT and to cooler not in TOSQAN. Heater mitigation means was investigated in MISTRA and PANDA. Thus, an amount of fourteen tests were performed in the project. In this paper we present the experimental work performed in each facility as well as an overview of the experimental results