Resource recovery and remediation of alkaline wastes

Over half a billion tonnes of alkaline (i.e. bleach-like) wastes are produced globally each year by industries such as steel production, alumina refining and coal-fired power generation. These wastes are currently stored in piles or landfill and can pose serious environmental hazards. Water that filters through the waste is toxic to aquatic life and dust generated as it is moved and stored is a public health hazard. It can take decades for these risks to fade. On the other hand, alkaline wastes contain large quantities of materials we would like to recover for re-use, particularly metals important to the technologies of the future, such as vanadium, used in steel manufacture for offshore wind turbines, lithium and cobalt for vehicle fuel cells and rare earth elements crucial for next-generation solar power systems. The obvious solution: using the profits from recovering resources locked in the waste to pay for remediation of the pollution, is hampered by the environmental damage caused by digging up stored waste piles and the expense of extracting the metals from the waste using existing technology.

Ground-breaking pilot research recently conducted by the team proposing this project shows that harnessing the power of low-cost, low-energy natural processes could solve the problem. We are developing a unique 'biomining' approach to increase the rate at which resources stored in the waste dissolve into water passing through it. Our pilot tests have shown that covering the waste pile with a layer of 'solid municipal waste' (compost) is very effective in driving this process. As water flows through waste treated with compost, metals like vanadium leach out to levels over twice those of untreated piles. The metal solution then flows out of the bottom of the waste pile under gravity. The high concentrations mean that extracting metals from this solution becomes viable using existing technology which we propose to implement as part of this project. In effect the valuable resources are extracted without digging up the waste.

The resource recovery benefits are matched by benefits to the environment. The layer of compost reduces dust generation from the site, and allows more CO2 to penetrate into the pile where it is locked away in significant quantities by reacting to form solid carbonate minerals. As elements like vanadium are pollutants as well as resources, recovery will eliminate the pollution alkaline waste weathering causes. Furthermore, the weathered waste piles have ideal conditions for nationally-scarce, orchid-rich plant communities to become established, making them suitable for restoration to create habitat of high conservation value.

In order to turn the extremely promising results of our pilot studies into optimised, industry-ready processes we must better understand the specific mechanisms which control the biomining and develop a road map for negotiating the economic, legislative, environmental and societal challenges to the implementation of a new technology in an established industry with strict requirements for environmental protection. Our proposed research will tackle both these aspects in parallel. The combined package: recovery of the metal resources while suppressing dust, increasing carbon sequestration and treating the pollution caused, would be hugely beneficial to partners in our project from both industry (Tata Steel, Rio Tinto and the Minerals Industry Research Organisation) and environmental protection (Environment Agency).

The project will bring together key commercial partners with a multi-disciplinary team of environmental scientists, waste policy experts and specialists in systems analysis and stakeholder engagement to pave the way for transforming resource recovery and environmental remediation. This team will investigate the key obstacles to this transformation and identify potential remedies, such as lobbying for legislative change or making a clear business case for resource recovery.

The proposed work represents a major step towards delivering a new paradigm in how we manage alkaline residues, which puts environmental protection and enhancement at its core.
Beneficiaries include:

HEIs in the network; NERC; KTNs
Impacts:
- Relationship building and knowledge exchange
- Credible opportunities for securing funding
- Development of systems approach tailored to deliver 'impact' from environmental R&D

Business Organisations: Tata Steel Europe; Rio Tinto, MIRO; steel, KTNs
Impacts:
- Increased productivity from resource recovery
- Reduced carbon emissions and environmental remediation costs
- Enhanced ecosystem services
- Enhanced environmental reputation
- New business opportunities in high-value mineral recovery

Environmental and wildlife organisations: Natural England; Yorkshire Wildlife Trust; RSPB
Impacts:
- New tools for working with industry to protect the environment
- New advice to government
- Direct partnership with industry stakeholders and input into industrial developments

Government & Policy Organisations: Government (national & local, DEFRA & Environment Agency); Local Nature Partnerships
Impacts:
- Contribution to CO2 reduction and environmental enhancement/protection targets
- Enhanced stakeholder interaction methods
- Enhanced UK competitiveness of key industries
- New policy input

Societal Organisations: Local communities; Recreational/tourism orgs. (e.g. River Trusts)
Impacts:
- Reduced environmental risk
- Increased profitability of key employers
- Enhanced natural environment
- Greater participation in local decision making.
- Reduced risk to, and enhancement of, tourist environments (e.g. rivers)

Methods for stakeholder engagement and delivering impact:
Project Board: key stakeholders in industry (e.g. MIRO, Tata, Link2Energy), regulators (Environment Agency) and academia will convene to provide a forum for knowledge exchange and strategic development of the research theme.

Regulatory engagement: The Environment Agency have agreed to monitor the trial - a key step in obtaining regulatory approval for new environmental technologies

Interviews & workshops: Interviews will alert stakeholders of new approaches and allow them to identify and consider challenges to practical deployment.

Network activities. We will take an active role in KE networks (RRfW, SoS minerals, CO2Chem) to engage with academics and industries.

PR. We will communicate our science to the public through popular media (websites, social media, press) and engage with schools groups.

Publications & conferences. MIRO and CL:AIRE will aid dissemination to the minerals, contaminated land and environment sectors. We will present our work at academic and industry facing conferences (e.g. IMWA, 2017) and publish in leading journals (e.g. ES&T).

Future funding development: We will develop and submit funding proposals with key stakeholders to relevant schemes (e.g. TSB, EU, KTPs, Follow On Fund) to take the technology to full scale deployment. EU proposals (Horizon 2020) are an obvious target given the research fits perfectly with work programme addressing societal challenge 5 in which Waste2Resource is a key thread. The fact that we have support from companies operating globally (e.g. Rio Tinto, Tata) offers tangible promise for internationalisation.

Milestones and measures of success
- Successful approval from EA on field trial for full scale deployment.
- Follow-on-funding for full scale deployment of remediation / recovery technology
- Exploitation of know-how by project team.
- Workshops - promoting industrial symbiosis between project stakeholders.
- Destination of research staff - e.g. in KTPs to further support development of recovery process.

Summary of impact resources: Project board (£5k), international KE (£2.5k), interviews (£12.5k), workshops (£3k), sub-contracts to MIRO (£16k) and CL:AIRE (£10k).