Resource recovery and remediation of alkaline wastes

全球每年由钢铁生产、氧化铝精炼和燃煤发电等行业产生的碱性（即类漂白剂）废物超过5亿吨。这些废物目前被堆放在堆填区或填埋区，可能造成严重的环境危害。通过废物过滤的水对水生生物有毒，在移动和储存过程中产生的灰尘对公众健康构成危害。这些风险可能需要几十年的时间才能消退。另一方面，碱性废物中含有大量我们希望回收再利用的材料，特别是对未来技术很重要的金属，比如用于海上风力涡轮机的钢铁制造的钒，用于汽车燃料电池的锂和钴，以及下一代太阳能发电系统的稀土元素。显而易见的解决方案是：利用回收废物中锁定的资源所获得的利润来支付污染的修复费用，但由于挖掘储存的废物堆造成的环境破坏，以及使用现有技术从废物中提取金属的费用，这种做法受到了阻碍。提出这个项目的团队最近进行的开创性试点研究表明，利用低成本、低能耗的自然过程的力量可以解决这个问题。我们正在开发一种独特的“生物采矿”方法，以提高储存在废物中的资源溶解到通过它的水中的速度。我们的试点试验表明，在废物堆上覆盖一层“固体城市废物”（堆肥）对推动这一过程非常有效。当水流经经过堆肥处理的废物时，钒等金属的含量是未经处理的两倍多。金属溶液在重力作用下从废料堆底部流出。高浓度意味着利用现有技术从该溶液中提取金属是可行的，我们建议将其作为该项目的一部分实施。实际上，有价值的资源在没有挖掘废物的情况下被提取出来。资源回收效益与环境效益相匹配。堆肥层减少了现场产生的灰尘，并允许更多的二氧化碳渗透到堆中，通过反应形成固体碳酸盐矿物，将大量二氧化碳锁在堆中。钒等元素既是污染物又是资源，回收可以消除碱性废物风化造成的污染。此外，风化的废物堆为全国稀缺的、富含兰花的植物群落的建立提供了理想的条件，使它们适合恢复，以创造具有高保护价值的栖息地。为了将我们的试点研究的极有希望的结果转化为优化的，工业准备的过程，我们必须更好地了解控制生物采矿的具体机制，并制定一个路线图，以谈判经济，立法，环境和社会挑战，在一个严格要求环境保护的成熟行业中实施新技术。我们提出的研究将并行处理这两个方面。综合方案：回收金属资源，同时抑制粉尘，增加碳封存和处理造成的污染，将极大地有利于我们项目的合作伙伴，无论是工业（塔塔钢铁，里约热内卢Tinto和矿产工业研究组织）和环境保护（环境局）。该项目将把主要商业伙伴与一个由环境科学家、废物政策专家、系统分析专家和利益相关者参与专家组成的多学科团队联合起来，为资源回收和环境补救的转变铺平道路。该小组将调查这一转变的主要障碍，并确定潜在的补救措施，如游说立法改革或为资源回收制定明确的商业案例。

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.