Diethyl carbonate removal from water

In LIBs (lithium batteries) the use of high-quality electrolyte solvents like DEC, having extremely low water (< 50 ppm) content is vitally important to achieving high electrochemical performance.

Other uses of diethyl carbonate include being harnessed as a solvent for intramuscular injections of antibiotics like erythromycin which is mainly used to treat bacterial and respiratory infections.

Separation of the black mass is carried out using hydro-metallurgy – a physicochemical process.

Solvents used in the electrolyte end up in the polluted wastewater resulting from this process. Wash-water will be similarly affected.

Therefore, all black mass separation plants need effective facilities to remove diethyl carbonate and other solvents from wastewater before it can be re-used or discharged. For companies aiming for ZLD (zero liquid discharge) this may be challenging.

The Nyex Ellenox™ electrochemical oxidation water treatment process is the most effective way to remove diethyl carbonate electrolyte solvent from wastewater. They work by producing powerful hydroxyl (·OH ) radicals that indiscriminately attack even hard-to-adsorb compounds like the solvents used in LIB electrolytes.

Nyex Ellenox™ systems from Arvia Technologies can easily scale to suit any size of operation and once set up, can be left virtually unattended.

They can either be used as stand-alone or as part of a water treatment train, often resulting in greater efficiencies from other processes.

A common disposal method for DEC and smilar reclcitrant compounds found in battery recycled wastewater is incineration. But this is by no means a carbon-neutral process, often involving sheaves of paperwork and tanker-loads of contaminated water travelling long distances before treatment.

For information on why incineration is a poor alternative to more environmentally-responsible water treatments, see this article.

By far the most efficient and eco-friendly lithium battery recycling water treatment is the Nyex Ellenox™ system from Arvia Technologies. With no moving parts, no hazardous chemicals to tip-in, and no toxic sludge produced, Ellenox™ systems require little maintenance; their small footprint also means they can often be sited alongside existing processes.

A range of solvents is normally used in the three types of LIB electrolytes in common use (liquid, solid and gel.) Solvents are added to the electrolyte primarily to enable high ionic conductivity.

After discharge and disassembly, old LIBs are shredded to mechanically separate all the recyclable copper, plastic and aluminium. What’s left is a powdery substance known as black mass.

Black mass mainly contains oxides of cobalt, nickel and lithium – the main components of the electrolyte. These can be separated and used again in new LIBs. However, black mass produces water containing organics like DEC which will need to be removed for water reuse.

Our Nyex Ellenox technology can effectively remove organics like those found in battery recycled wastewater to allow for efficient wastewater recycling.

If you would like to know more about how our technology can help treat battery recycled wastewater see our case study.