Boric oxide preparation method
AssigneeSocieta Chimica Larderello S.p.A.
InventorsAntonio Vasconi, Paolo Mazzinghi
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Abstract
High-purity boric oxide which does not adhere to the reactor walls is obtained by: (a) gradually heat in boric acid, with the absence or substantial absence of fusion phenomena, at increasing temperature to a value not exceeding about 150.degree. C.; operating at below atmospheric pressure, to eliminate water until the boric acid has been completely or substantially completely converted into metaboric acid; (b) gradually heating the metaboric acid obtained in stage (a), with the absence or substantial absence of fusion phenomena, at increasing temperature to a value not exceeding about 400.degree. C., operating at below atmospheric pressure, to eliminate water until the metaboric acid has been completely or substantially completely converted into boric oxide.
Claims6
A process for preparing boric oxide substantially free of impurities derived from the corrosion of the production apparatus in which the boric oxide is in the form of a spongy, friable mass, said process comprising:
- (a) gradually heating solid boric acid without melting at least a substantial portion of said boric acid to a temperature not exceeding about 150.degree. C. at below atmospheric pressure until said boric acid is at least substantially converted into solid metaboric acid;
- (b) gradually heating said solid metaboric acid without melting at least a substantial portion of said metaboric acid to a temperature not exceeding about 400.degree. C. at below atmospheric pressure until said metaboric acid is at least substantially converted into said boric oxide;
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- (c) recovering said boric oxide, wherein said boric acid, metaboric acid and boric oxide do not adhere to the production apparatus.
Dependencies are inferred from the claim text.