Submarines and military fighters are powered by large alkaline batteries weighing almost 14 tonnes. Although such batteries last for up to 12 years, scientists from Moscow believe they have a future after recycling.
The National University of Science and Technology (NUST) in Russia has developed a method to recover silver from bulky end-of-life batteries serving military applications. The precious metal can be used to create new high-grade batteries for submarines as well as aircraft.
The Russian scientists say ‘heavy-duty’ batteries contain roughly seven tonnes of pure silver plates. In the last decade, local manufacturers of silver-zinc batteries started adding 10-15% lead to the silver. ‘This lowers the costs and does not affect the performance of the product but almost completely blocks the process of subsequent recycling,’ the NUST specialists point out.
The university says its ‘innovative cascade method’ for purifying silver from lead-containing batteries now allows secondary use that can save millions of dollars for each one produced.
Tests have been successfully conducted at the JSC Shchelkovo Plant of Secondary Precious Metals. Here, the silver was melted in a two-stage process, after which lead was removed and a commercial product of 99.99% purity is obtained from raw materials with 85% silver content. ‘The pure product corresponds to all state standards,’ it is reported.
Very little new equipment has had to be installed at the facility, apart from a low-cost, high-speed, melt cooling unit.