Q&A Results with ElectraMet: Copper recovery from CuCMP Wastewater

At UPM 2023, Cameron Lippert, Co-Founder and Chief Innovation Officer at Electramet, presented a novel method for copper recovery from waste streams.

Below are the answers to your questions for the presenter.

If you missed the presentation, catch up with the recording on the Technical Knowledge Base. Alternatively, read the full technical article in the UPM Journal Archive.

1. Is this an electrowinning process or something completely different?

ElectraMet® uses similar concepts to electrowinning but is a different technology. The design of the reactor/separation cell is quite different and uses much less electricity. The innovative design directs flow, utilizes specific material science, and tightly controls voltage to target and remove specific dissolved metal contaminants to <1 mg/L levels, which is well below electrowinning’s capability.

2. Does the amount of copper generated per fab create sufficient revenue to pay for the system?

The revenue depends on the copper mass in the given volume of water. Total cost of ownership over 3+ year periods show strong advantages for ElectraMet systems. Copper sales help to reduce the total cost of ownership but revenue rarely exceeds treatment costs. Some metals, like silver, have shown rapid payback and revenue positivity.

3. How do you control CuSO4 scaling when removing copper rich material from the reactor

Cu is plated in the ElectraMet reactor process across a wide range of pH conditions. The cartridge materials combined with the specific voltage differential deliver absolute specificity for copper. As a result, ElectraMet has not experienced CuSO4 scaling.

The regeneration solution (H2SO4 & H2O2) has been researched and validated over several years to assure robustness. While scaling has not occurred, if it were to occur, the ElectraMet regeneration process would clear this scale. Pressure along with many other parameters are tracked in real time to limit correct any process difficulties seen by the system in delivering copper removal.

4. Does TSS cause fouling or operational issues for this type of treatment. Do you have pre-treatment that addresses TSS?

The presence of TSS is a significant problem if the particle size is >100 nm and will cause pressure-limiting flow for the system. We implement pre-treatment to remove the TSS before entering the ElectraMet system and utilize a backflush, as needed, to remove any TSS that makes it through to the system.

Cartridge or ultra-filtration systems can be used along with concentration systems to address TSS concerns.

5. Could this process be used to recover other metals, such as Mn

Yes. ElectraMet is used for other metals such as Mn, Ag, Cd, Co, Ni, and more.

6. What type of maintenance procedures are required? What are the consumables?

Maintenance includes general visual inspections to assess the bulk removal filter and parameters included in the site SOP. ElectraMet typically performs an annual visit and replacement of the ElectraMet modules. The system monitors [Cu] in real time, so changes in upstream process are quickly identified and may be investigated.

Electricity and a chemical oxidizer, usually peroxide, are the only consumables, although a small amount of sulfuric acid may be added at times.

7. Does your catalyst bed require backwashing? Is there any catalyst loss or effectiveness loss over time?

No backflush is required for routine H2O2 operation. A backflush is performed only when a pressure drop is observed. For most streams there will be no loss in catalyst performance over time. Certain water quality will result in the media needing to be replaced annually.

8. What are the limitations of the catalyst? Can it work in alkaline conditions?

We use 2 different media types that can address a wide range of water quality. Both media can be used under alkaline solutions while only one of the media is used under acidic conditions.

9. Is there a limit to how low your system can go?

H2O2 systems are generally deployed to support dissolved metal removal, so a target of 5 ppm is used. The media can be used for match processing (multiple passes) and inline flow (using sequential passes of separate beds) to deliver levels <1 ppm.

ElectraMet M-cartridges remove H2O2 and O3 very effectively also, so a multi-pass media bed with final polish with ElectraMet cartridges could produce very low ppb or ppt concentrations provided adequate conductivity of the stream.

10. How frequently do you hit the discharge limit?

Our operating contracts specify compliance assurance. Systems are designed to achieve discharge compliance and/or impurity removal 100% of the time. A location using an ElectraMet system has never experienced a discharge compliance issue.

11. What are the impacts of Cu recovery on water reclaim feasibility?

ElectraMet’s removal of dissolved metal(s) generates O2 and H+. There are no waste byproducts generated that would impact reclaim feasibility.

To learn more, catch up with the recording on the Technical Knowledge Base. Alternatively, read the full technical article in the UPM Journal Archive.