Title:
METAL AND TIN ALLOY HAVING LOW α-RAY EMISSION, AND METHOD FOR PRODUCING SAME
Document Type and Number:
WIPO Patent Application WO/2019/035446
Kind Code:
A1
Abstract:
Provided is a metal which is one of tin, silver, copper, zinc, or indium, and has low α-ray emission, wherein the α-ray emission of the metal after being heated in air at 100°C for 6 hours is 0.002 cph/cm2 or less. A metal selected from among tin, silver, copper, zinc, and indium, each of which contains lead as an impurity, is dissolved in an aqueous sulfuric acid solution to prepare an aqueous solution of a sulfate of the metal, and lead sulfate in the aqueous solution is removed by precipitation. While stirring the aqueous sulfate solution from which lead sulfate has been removed, an aqueous lead nitrate solution containing lead having an α-ray emission of 10 cph/cm2 or less is added to the aqueous sulfate solution to precipitate lead sulfate in the aqueous sulfate solution, and the aqueous sulfate solution is circulated while removing lead sulfate. The metal is electrolytically collected using the aqueous sulfate solution as an electrolytic solution.
Inventors:
HIRANO HIROTAKA (JP)
YOSHIDA YOSHIHIRO (JP)
KATASE TAKUMA (JP)
YOSHIDA YOSHIHIRO (JP)
KATASE TAKUMA (JP)
Application Number:
PCT/JP2018/030211
Publication Date:
February 21, 2019
Filing Date:
August 13, 2018
Export Citation:
Assignee:
MITSUBISHI MATERIALS CORP (JP)
International Classes:
C25C1/14; C22B11/00; C22B15/14; C22B19/32; C22B25/08; C22B58/00; C25C1/12; C25C1/20; C25C1/22
Domestic Patent References:
| WO2012120982A1 | 2012-09-13 |
Foreign References:
| JP2017057451A | 2017-03-23 | |||
| JP2016074969A | 2016-05-12 | |||
| JP2014169502A | 2014-09-18 | |||
| JP2017510706A | 2017-04-13 | |||
| JP2011214040A | 2011-10-27 | |||
| JP2017157394A | 2017-09-07 | |||
| JP2018142195A | 2018-09-13 | |||
| JPS528532B2 | 1977-03-10 | |||
| JP4472752B2 | 2010-06-02 |
Other References:
B. NARASIMHAM ET AL.: "Influence of Polonium Diffusion at Elevated Temperature on the Alpha Emission Rate and Memory SER", IEEE, 2017
Attorney, Agent or Firm:
MATSUNUMA Yasushi et al. (JP)
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