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US 4,687,601 AGranted
Process for the preparation of pulverulent metallic oxides from metallic nitrates
AssigneeComurhex
InventorsRoland Bachelard, Philippe Joubert
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AssigneeComurhex
InventorsRoland Bachelard, Philippe Joubert
Estimating the term…
Process for the preparation of pulverulent metallic oxides with predetermined reactivity which is adjusted by the specific surface area, which are intended to be subjected to subsequent conversions, by thermal treatment of corresponding nitrates in the form of an aqueous solution or of a solids material, consisting of hydrated uranyl nitrate, on its own or in admixture with at least one of thorium nitrate, cerium nitrate and plutonium nitrate, which process is characterized in that it consists of two treatment stages: (a) the first stage essentially consisting of incompletely dehydrating the hydrated uranyl nitrate. (b) the second stage essentially consisting of decomposing the product resulting from the first stage by calcination under controlled steam pressure. The process is used for obtaining uranium oxide on its own or in admixture with thorium oxide, cerium oxide and plutonium oxide, with a view to subsequent chemical conversions and/or sintering.
A process for the preparation of pulverulent metallic oxides having a selected specific surface area by thermal denitration of metallic nitrates selected from the group consisting of hydrated uranyl nitrate and hydrated uranyl nitrate in admixture with at least one other nitrate selected from the group consisting of thorium, cerium and plutonium comprising a first step of heating said metallic nitrates to a temperature between 160.degree. and 300.degree. C. to at least partially dehydrate said dehydrated uranyl nitrate and a second step of calcining the product resulting from said first step by heating the product at a temperature between 260.degree. and 600.degree. C., while subjecting the product to steam pressure, said steam pressure being at most equal to one bar with the amount of steam pressure being selected depending upon the desired specific surface area of the pulverulent metallic oxide(s).
Dependencies are inferred from the claim text.