LOW alpha-RAY EMISSION STANNOUS OXIDE AND METHOD OF PRODUCING THE SAME

Patent metadata

Field	Value
Publication number	US-2024294391-A1
Application number	US-202418653084-A
Country	US
Kind code	A1
Filing date	May 2, 2024
Priority date	Jul 30, 2018
Publication date	Sep 5, 2024
Grant date	—

Abstract

What is provided is stannous oxide having an α-ray emission amount of 0.002 cph/cm 2 or less after heating in an atmosphere at 100° C. for 6 hours. Tin containing lead as an impurity is dissolved in a sulfuric acid aqueous solution to prepare a tin sulfate aqueous solution, and lead sulfate is precipitated in the aqueous solution and removed. While stirring the tin sulfate aqueous solution from which lead sulfate has been removed, a lead nitrate aqueous solution containing lead having an α-ray emission amount of 10 cph/cm 2 or less is added to cause lead sulfate to be precipitated in the tin sulfate aqueous solution, and simultaneously the tin sulfate aqueous solution is circulated while removing the lead sulfate from the aqueous solution. A neutralizing agent is added to the tin sulfate aqueous solution to collect stannous oxide.

First claim

1 . (canceled)

2 . (canceled)

3 . A method of producing stannous oxide having a low α-ray emission amount, the method comprising:
a step (a) of dissolving tin containing lead as an impurity in a sulfuric acid aqueous solution to prepare a tin sulfate aqueous solution and performing a first precipitation of lead sulfate by causing lead sulfate to be precipitated in the tin sulfate aqueous solution;
a step (b) of filtering the tin sulfate aqueous solution containing the lead sulfate obtained from the step (a) to remove the lead sulfate from the tin sulfate aqueous solution;
a step (c) of performing a second precipitation of lead sulfate in the tin sulfate aqueous solution by adding a lead nitrate aqueous solution containing lead having an α-ray emission amount of 10 cph/cm 2 or less to a first tank for over 30 minutes while stirring the tin sulfate aqueous solution, from which lead sulfate has already been removed, obtained from the step (b) at a rotation speed of at least 100 rpm to cause lead sulfate to be precipitated in the tin sulfate aqueous solution, simultaneously circulating the tin sulfate aqueous solution so that a circulation flow rate is at least 1 vol %/min with respect to a total liquid amount in the first tank while filtering the tin sulfate aqueous solution to remove lead sulfate which has been precipitated from the tin sulfate aqueous solution a second time; and
a step (d) of adding a neutralizing agent to the tin sulfate aqueous solution obtained from the step (c) to collect stannous oxide.

4 . The method of producing stannous oxide having a low α-ray emission amount according to claim 3 ,
wherein a concentration of lead nitrate in the lead nitrate aqueous solution in the step (c) is 10 mass % to 30 mass %.

5 . The method of producing stannous oxide having a low α-ray emission amount according to claim 3 ,
wherein an addition rate of the lead nitrate aqueous solution in the step (c) is 1 mg/sec to 100 mg/sec per 1 L of the tin sulfate aqueous solution.

6 . The method of producing stannous oxide having a low α-ray emission amount according to claim 4 ,
wherein an addition rate of the lead nitrate aqueous solution in the step (c) is 1 mg/sec to 100 mg/sec per 1 L of the tin sulfate aqueous solution.

Assignees

• Mitsubishi Materials Corp

Inventors

• Hirano Hirotaka
• Yoshida Yoshihiro
• Katase Takuma

Classifications

• C25D21/14

  Controlled addition of electrolyte components · CPC title

• C01P2006/44

  Alpha, beta or gamma radiation related properties · CPC title

• B01J2219/00189

  controlling the stirring velocity · CPC title

• B01J19/0086

  Processes carried out with a view to control or to change the pH-value; Applications of buffer salts; Neutralisation reactions · CPC title

• B01J19/0066

  Stirrers (mixing per se B01F) · CPC title