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Title: Zirconium and uranium recoveries from a ZrSiO$sub 4$ and ZrO$sub 2$ mineral (Caldasito) from the Pocos de Caldas Plateau, the State of Minas Gerais, Brazil (in Portuguese)

Thesis/Dissertation ·
OSTI ID:4375842

Thesis. A commercial-gnade zirconium dioxide (Zr, Hf)O/sub 2/ and a sodium diuranate (SDU) or ammonium diuranate (ADU) processing is presented. These compounds are obtained from the Caldasito, from the Pocos de Caldas Plateau in the southern part of the State of Minas Gerais, Brazil. The processing scheme is developed in three steps: the chemical opening of the ore, the uranium- zirconium separation and the zirconium purification. The uranium-zirconium sepanation takes place by a liquid-liquid extraction in the TBP-varsol-HNO/sub 3/- H/sub 2/O system, using as organic phase a mixtare of TBP 36% v/v-varsol. The yield of the uranium extraction, in a single and discontinuous stage is higher than 80% in U/sub 3/O/sub 8/. The zirconium extraction by the tributyl phosphate (TBP) in dilute nitric acid is negligible. The raffinate (zirconyl nitrate) is purified by an ion-exchange operation with a strong cationic resin. Aluminium, titanium, and iron are the most important impurities in the aqueous solution. The zirconium nitrate is transformed into a colloidal solution, the zirconium being not retained by the column. The zirconium in the effluent is precipitated by ammonium hydroxide and calcined to a commercialgrade zirconium dioxide. By this procedure it is possible to produce a commercial-grade oxide higher than 97% in ZrO/sub 2/. (INIS)

Research Organization:
Sao Paulo Univ. (Brazil). Escola Politecnica
NSA Number:
NSA-29-012551
OSTI ID:
4375842
Report Number(s):
INIS-mf-943
Resource Relation:
Other Information: Thesis. Orig. Receipt Date: 30-JUN-74
Country of Publication:
Brazil
Language:
Portuguese