Reducing the industry’s carbon footprint
The first step in reducing the carbon footprint and environmental effects of the HPA industry is to reduce the power requirement for manufacturing processes. This starts with the design of the processes and the manufacturing plant to implement them. As a basis to reduce power consumption, hydro metallurgy processes use much less power than thermal process steps.
AEM’s proven chlorine leach–crystalline purification (CLCP) process currently emits 12% fewer carbon emissions than the alkaloid process and is expected to reduce to zero in Q3 of 2023. Close co-operation with the laboratory is the basis for continuous improvement in the plant. This provides the plan for eliminating the Scope 1 category of emissions.
The CLCP process produces almost zero waste. Hydrochloric acid, an important input chemical, is recycled many times within the process before being discharged. As a by-product, it predominantly takes the form of aluminium chloride, which is sold for use in water treatment. The water from our processes that we do not recycle is treated and released under strict guidelines.
The next step is to source the required power from green sources. A location rich in hydropower and wind farms is of the essence. This leads to both predictable pricing and fulfilment of environmental criteria. By-products are produced with hydropower and, as a result, there are no Scope 2 emissions.
Manufacturing high purity alumina does not occur in a vacuum. This means that reducing Scope 3 emissions requires paying attention to the inputs and outputs of production. The feedstock must arrive and bring with it a carbon footprint of zero. This can be achieved if the supplier uses hydro or wind power exclusively, ideally within the company from its dams or wind installations. It is, of course, simplest if the supply is from a secured source located nearby. An alternative feedstock is aluminium from decommissioned factories.
The product going out must match the customers’ requirements exactly so that they can minimise their process steps and maximise their productivity. This means that high purity alumina cannot be seen as a commodity product where the customisation is left to the customer, a wide and versatile product portfolio is needed. Powder particle size can be controlled both at the crystal-growing stage and via subsequent milling – although the latter requires careful control to avoid contamination by the grinding media. Powder must be tailored to a customer’s specific requirements for particle size, densification, and doping. Pellets (compacted powder in a ‘puck’ shape) must also meet exacting specifications to fulfil their applications.
Customisation to meet special requirements involves simulation, development in the laboratory, and transfer to production.
Quality controls after manufacturing complete the technical involvement to the benefit of the customer, with a location convenient to North American and European markets that simplifies shipping.
Even if the site is not in a location where every turn of a spade is audited and certified, transparency must be maintained for internal and external purposes. All systems are running to identify where things come from and where they are going and logging of operations is ongoing in preparation for internal and external audits. As we have seen, sustainability depends on many factors. Process design, the reduction of power requirements, an advantageous site, green energy sources, clean feedstocks, and customised products are all important to sustainably produce and deliver ultra-high purity alumina.
Customisation to meet special requirements involves simulation, development in the laboratory, and transfer to production
1. AEM Internal data
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global and national CO2 emissions from fossil fuel combustion and
cement manufacture: 1751–2017”
4. https://www.recyclingtoday.com/news/worldsteel-co2-report/
5. https://www.iea.org/reports/iron-and-steel
6. https://www.mckinsey.com/industries/metals-and-mining/our-insights/decarbonization-challenge-for-steel
7. https://www.reuters.com/business/sustainable-business/norways-sovereign-wealth-fund-tells-companies-set-zero-emission-goals-2022-09-20/
8. https://www.weforum.org/agenda/2022/09/norways-massive-sovereign-wealth-fund-sets-net-zero-goal/
9. https://www.innovationnewsnetwork.com/ultra-high-purity-alumina-sustainably-manufactured-canada/20960/
10. https://www.nationalgrid.com/stories/energy-explained/what-are-scope-1-2-3-carbon-emissions
11. https://ghgprotocol.org