After several years of research and fine tuning of the technology, STC has realized a demo plant able to regenerate about 2 t/d of lead oxides starting from exhausted lead paste without involving pyrometallurgical processes.
The system is based on a patented process, which employs sodium hydroxide or carbonate, ammonium carbonate or the STC innovative U4LEAD process to implement the lead paste desulphurization reaction for the transformation of lead sulphate into lead carbonate.
Although the mentioned reaction has been known for many years, in this case the adopted engineering expedients allowed to achieve yields close to 100%. A lead paste treatment, where the drying temperature is higher than the PbCO3 decomposition temperature, leads to the formation of oxide, a compound that is easily leached in the following step in order to preprecipitate high purity lead carbonate.
The following low temperature heat treatment leads to the production of pure lead oxides of different types: litharge, massicot or minium which might be used both for the production of active material for batteries (starter and traction batteries), and for any other use this pure compound is thought for (ceramic, glass and rubber industries, etc).
The by-product deriving from the whole cycle may be used as fertilizer and sold for agricultural applications.
Furthermore, an experimental batch of about 1000 starter batteries has been produced with the hydrometallurgical Lead Oxide Regeneration technology proposed by STC. After several tests, it has been proved that the obtained batteries containing the regenerated nanostructured oxides have a greater capacity and a longer life than those produced with traditional processes.
The STC LEAD3 technology makes it possible to have a remarkable economic saving, a virtually nonexistent environmental impact and the possibility to supply battery producers with oxides that are ready for the production of new batteries with better characteristics than the traditional ones.
|Gripping, Weight Loss [%]||79%||15%|
|Available Power Midtronics [CCA - Cold Cranking Amps]||600||625|
|Ciclability [N° cycles]||115||136|
|C20 afterciclability test [Ah]||22||27|