Lead metallurgy

The objective of the project "Lead metallurgy" was to improve the technologies for recycling lead-acid batteries leading to better resource use and a reduction of primary energy consumption. The project partners have developed a method which can recycle the plastic residues and the tin and antimony contained in waste rechargeable lead batteries.

Lead-acid batteries are used as starter batteries in cars, in industrial production and for electricity storage technologies in electric vehicles and for power supply. Lead prices have risen sharply over the last few years which is why effective recycling can help to lower production costs.

In the conventional recycling of used lead-acid batteries, after grinding and sorting, the so called plastic waste fraction is disposed of in hazardous waste incineration plants. In this project, a technology was developed which is able to separate the plastic residues into a lead-rich fraction, a heavy plastics one and a residual fraction. The lead-rich shares are immediately fed into lead recycling and thus improve the effectiveness of the smelting process. The application options for the heavy plastics as a secondary raw material are being examined. Only the residual fraction still has to be incinerated, which substantially reduces CO₂ emissions.  

In the second sub-project, processing options were examined for the recycling products occurring during lead refining. For instance, the antimony slag and the tin powder can be separated into the metals lead, antimony and tin and their alloys by applying suitable reducing processes. This makes it possible to extract and further use antimony as a potential recyclable. The tin and the alloys obtained can be directly used to produce conventional lead alloys. This greatly increases the effectiveness of lead production.

The developed methods increase the lead output in the joint research group by 85 tons per year and make it possible to extract 200 tons of antimony and tin each year.