Italian company STC is revamping a lead-acid battery recycling plant in Serbia so it is more environmentally friendly.
The revamped plant is due to come online in October, with a capacity of around 20,000 tons of lead per year, which will supply the European battery-making market.
The project involves the conversion of the existing live steam crystallisation system— used for the sodium sulphate solution coming from paste desulphurisation— into a Mechanical Vapour Recompression (MVR) system.
In the new configuration, the heat necessary to evaporate the sodium sulphate solution is obtained by the adiabatic re-compression of the evaporated steam rather than using live steam produced in a dedicated steam generator fed with natural gas.
An STC spokesman told BEST: “The main benefits of mechanical vapour recompression system over the crystallisation process is related with production costs as the gas consumption used for the crystallisation is drastically reduced against a slight increase of electric energy consumption.
“The company will save about 2,000.000 nm3 of natural gas. The other advantage is for the environment; we calculated a reduction of CO2 emitted in the amount of some 3,500 ton per year and nox reduction of about 20,000 kg per year.
“Once the compressor is working, the process of crystallisation with mechanical vapor recompression does not need any gas consumption except for a very minimum amount necessary to compensate the heat loss of the circuit or for the transitory start-up period.”
STC capability ranges from battery breaking to production of final lead ingots and includes lead smelting and refinery sections, paste and grids desulphurization units, salt crystallization units, electrolyte purification and concentration unit, wastewater treatment plant, air pollution control systems and polypropylene upgrading units.