| 摘要 |
Scrap tin plate is detinned in a continuous process by conveying it through a detinning bath containing concentrations of sodium hydroxide and of sodium nitrate or sodium nitrite which are substantially higher than standard practice. The solution is heated to a temperature higher than is used in standard practice. With this relatively high concentration and temperature the tin reacts with the sodium salts in the solution to form sodium stannate, which precipitates out of the solution and is continuously separated therefrom in a centrifuge or filter press. The detinned scrap is rinsed with water as it emerges from the detinning bath and the used rinse water drains into the detinning bath to serve as a makeup liquid.
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