Why are Aluminum Billets Homogenized?

Abstract:

Homogenizing Aluminum billets is a vital heat treatment process that ensures uniformity in microstructure, improves mechanical properties, and optimizes extrusion efficiency. By controlling temperature, alloy composition, and grain structure, homogenization enhances Aluminum billets’ performance, making them more suitable for downstream applications.

Technical Explanation

Homogenizing Aluminum billets involves a three-step heat treatment process: heating, soaking, and cooling.

1. Heating: The billets are heated to a temperature close to their solidus point, based on the alloy composition, to prepare for further treatment.
2. Soaking: At the desired temperature, billets are maintained for a set duration. This allows alloying elements to dissolve into a solid solution and transforms brittle phases into spherical forms, improving plastic deformation capabilities.
3. Cooling: Controlled cooling ensures that precipitates are evenly dispersed, optimizing precipitation hardening. The cooling rate significantly impacts the billet’s final mechanical properties.

Microstructure Before and After Homogenization:

• Before Homogenization: Coarse, irregular grains with distinct micro-segregation and visible intermetallic phases.
• After Homogenization: Uniform, finer grains with evenly distributed alloying elements and reduced brittleness, leading to enhanced strength and stability.

Impact on Billet Quality:

• Grain refinement, uniform temperature, and reduced residual stresses contribute to a more homogeneous microstructure, which improves mechanical properties and overall billet quality.

Benefits for Extrusion

Homogenization improves the extrusion process by:

• Enhancing Extrusion Efficiency: A uniform microstructure ensures smooth material flow, reducing the risk of cracking.
• Improving Mechanical Properties: Finer grains and evenly distributed elements increase strength, allowing for stronger extrusions.
• Superior Surface Finish: The controlled composition and refined grain structure ensure smoother, more consistent surfaces in extruded products.
• Better Dimensional Stability: Homogenized billets minimize extrusion speed variations, leading to consistent dimensional accuracy.

Easy example for better Understanding

Think of homogenizing Aluminum billets like making a smooth batter for a cake. If you just throw all the ingredients together without mixing them properly, you will end up with lumps and uneven texture in the batter. But when you mix everything thoroughly, you get a smooth, even batter where all the ingredients are well-blended.

Similarly, homogenizing Aluminum billets ensures that the material is evenly heated and treated, making the grains smooth and consistent. This results in Aluminum that is stronger, more stable, and easier to work with, much like how a well-mixed batter bakes into a perfectly smooth cake.

Access to an uninterrupted supply of critical minerals such as copper, lithium, nickel, and cobalt, and future metals like aluminium, zinc and silver, are essential to the global economy successfully embracing and transitioning to a low carbon future. Consequently, securing such deposits at home or ensuring the unhindered access to such deposits across friendly resource-rich nations is integral to the long-term energy security efforts of nations around the world.

The demand for these critical and future metals and minerals is projected to grow exponentially over the coming years as each country pursues its net-zero objectives. As McKinsey reports,
the demand for all critical metals is expected to outpace absolute historical growth in the coming decade, with the demand for copper especially leading the race. While this trend is likely to result in short-term measures like resource nationalism gaining popularity, the more sustainable and long-term answer to this dilemma perhaps lies in the ambit of greater cooperation and collaboration amongst countries that are best placed to work together to unlock and secure such resources.

According to the International Energy Agency (IEA), today’s combined market size of key energy transition minerals is set to more than double to $770 billion by 2040. Meanwhile, an analysis by Bloomberg NEF (BNEF) states that the world could require 3 billion metric tonnes of such metals and minerals between 2024 and 2050 to build out low-carbon solutions such as
electric vehicles, wind turbines and electrolysers, as well as the infrastructure to support future generations. That number rises to 6 billion tonnes to reach net-zero in 2050.

Critical minerals: supply and demand issues

So, how do we solve this supply and demand dilemma? While many see this as a challenge, I see this as a huge opportunity for all of us.

Firstly, we must urgently secure and direct further investments into the sector. The most developed economies around the world have grown to where they are today on the back of a strong and robust critical minerals and natural resources sector. Consider the US, Europe,
Russia, the Middle East or Australia. While the sector has seen several large investments in the recent past, the global mining industry will need approximately $2.1 trillion in fresh investment by 2050 to meet the net-zero demand for raw materials.

These investments will also need to be supported by progressive policy and regulatory environments that allow for easy access to land and licenses, incentivize the use of world-class
technologies that support sustainable mining practices, permit self-certification of operations, and ensure an equitable distribution of returns.

Secondly, there is a strong need to support and secure the development of robust and reliable supply chains. The world is already responding to this need with the recent establishment of the
US-led transnational Minerals Security Partnership (MSP), which strive to promote responsible growth across the critical minerals sector via a shared commitment to high environmental, social and governance (ESG) standards, sustainability, and shared prosperity. The MSP already has the support of 23 partners, including Australia, Canada, India, Japan, the UK and the EU, and has overseen the execution of multiple bilateral and multilateral partnerships that are focused on enabling access to these resources or securing them for the future. Continued collaboration in this way will put us on a stronger footing to meet demand.

Alongside this, efforts to recycle and innovate are also vital as we seek to ease strains on supply. BNEF expects output from secondary sources to become an integral part of the supply chain for energy transition metals, with the added benefit of lowering the lifecycle emissions of supply. In this global quest, India stands as a key player and a clear partner of choice.

India’s untapped critical minerals

While India is blessed with vast mineral reserves, only about 20% of India’s geological wealth has been explored to date, thereby presenting an exciting opportunity to global investors and
partner countries. To name just two critical minerals, India has approximately 163.9 million tonnes of copper reserves, and approximately 44.9 million tonnes of cobalt ore resources, both of which – if unlocked in a timely, efficient and sustainable manner – could provide a much-needed boost to global supplies. India is also already pioneering ways to ensure recycled metals are part of the value chain, as evidenced by the government’s recent mandate that all new non-ferrous products must contain 5% recycled content from the beginning of the financial year 2027-28.

Additionally, India’s Ministry of Mines announced earlier this year that it plans to earmark about half of its planned domestic exploration projects to critical minerals such as graphite, molybdenum, nickel, cobalt, lithium and potash. Another important initiative is the National Critical Minerals Mission launched in 2024 which is aimed at reinforcing India’s critical mineral value chain across all stages – from exploration and mining to beneficiation, processing, and recycling of end-of-life products. This initiative is designed to ensure self-sufficiency in fulfilling the industrial demands for critical minerals.

These measures, as well as India’s stable government, progressive policies around the sector and in welcoming foreign direct investment in general, rapidly developing infrastructure, growing middle class, robust manufacturing ecosystems, and wealth of talent, position the country as a significant destination and partner to global players and countries seeking to explore or secure their critical mineral supply chains. As the world’s largest democracy and soon to be third largest economy, India has multiple reasons to seize the opportunity to help shape the future of the low carbon economy. As the world turns to India and India turns to the world, shouldn’t you?

In the ever-evolving landscape of construction, the adoption of sustainable processes and materials for creating structures has reshaped the industry. Driven by the goal of reducing human impact on the environment, architects and builders globally have increasingly embraced the Green Building revolution, focusing on creating energy-efficient and sustainable structures. Aluminium has been an integral component of this transformation, revolutionizing modern architecture with its sleek lines and myriad properties. Be it towering skyscrapers to small homes, aluminium is the material of choice owing to its light weight, durability, and recyclability.

Aluminium’s remarkable durability, which has a potential service life of over 80 years, enables it to withstand the rigors of extreme temperatures. Aluminium not only lightens the load borne by entire structures but also simplifies the process of achieving shape and form, granting architects the freedom to bring their visionary designs to life. For example, aluminium plates can offer the same stiffness as steel at half the weight, which significantly reduces foundational requirements and construction costs.

In the realm of construction innovation, aluminium formwork technology (known as Mivan technology) has emerged as a total game-changer. This system replaces traditional shuttering techniques in construction, allowing concrete structures to be erected faster, with greater precision, and less waste. Its robust yet lightweight panels not only halves the turnaround time for projects but are also reusable, slashing costs and environmental impact.

The architectural prowess of aluminium continues to shine in the design of towering skyscrapers, characterized by their floor-to-floor glass walls or glazed panes within aluminium frames. The metal significantly enhances the energy efficiency of any building by minimizing heat transfer and curtailing glare, thereby optimizing interior climate control. Integrating solar panels within these facades substantially reduces greenhouse gas emissions, thus lowering the environmental footprint of the building. Buildings certified under LEED (Leadership in Energy and Environmental Design) often recognize aluminium as a key sustainable material, underscoring its growing prominence in eco-friendly construction practices.

Aluminium is also increasingly valued in seismic retrofitting, particularly in regions vulnerable to earthquakes. Its unique combination of strength and lightness makes it an optimal choice for reinforcing existing structures. Buildings can be made more resilient to seismic activity without excessively increasing their structural load, ensuring safety without compromising the integrity of the original architecture. This allows for the effective renovation of older buildings, enhancing their ability to withstand earthquakes with minimal alteration to their structural or heritage aesthetics.

Presently commanding a significant chunk of the construction materials market, aluminium’s prominence in building and construction is undeniable. Its role is amplified by initiatives like India’s Smart City projects, which are further propelling its adoption. Aluminium is sculpting the sustainable cities of tomorrow by perfectly merging functionality with environmental responsibility.

India’s quest for economic growth and clean energy has put a spotlight on securing vital raw materials crucial for various technologies. Picture this: from solar panels to electric cars, these materials are the unsung heroes driving our modern world. To tackle this challenge head-on, the Ministry of Mines, Government of India, initiated auctions for 20 blocks of key minerals in November 2023, followed by 18 more in February 2024. These auctions cover a gamut of thirty minerals which are declared as Critical Minerals, which include nickel, cobalt, copper, graphite, manganese and lithium – minerals pivotal for India’s green energy transition. Also included in this list of critical minerals are few Rare Earth minerals notably scandium, neodymium etc.

Amidst this push, Vedanta Aluminium’s Research & Development (R&D) team’s initiative to recover graphite from used electrodes of our aluminium smelting units, and rare earth oxides from bauxite residues may really stand out to contribute to our nation’s quest of sourcing high quality graphite and rare earth minerals like scandium. Through our innovative R & D project, we are working towards extracting high-purity graphite powder (>99% purity) from Spent Pot Lining (SPL) and Shot Blast Dust – two waste products generated in the making of aluminium metal from alumina powder. This solution aligns with Vedanta Aluminium’s ESG (Environmental, Social, and Governance) principles and can contribute significantly to the circular economy agenda promoted by it.

The recovered graphite demonstrated highly promising results in electrical conductivity and its structural properties are suitable for applications in energy storage devices. The atomic structure of this recovered graphite is observed to be extremely useful for a process called Lithiation and De-lithiation and makes it suitable for the manufacturing lithium-ion batteries – which are vital for everything from smartphones to electric cars. This disruptive development and evaluation of subsequent application was developed in collaboration with the Institute of Minerals and Materials Technology (IMMT), a reputed CSIR Laboratory in Bhubaneswar. Closer home, this graphite can be used in the production of electrodes for aluminium production at our mega aluminium plants and can also fulfil the need for our country’s critical need for graphite.

Graphite’s importance cannot be overstated. With over 70% of India’s graphite being imported due to low-quality domestic reserves, the stakes are high. In FY23 alone, India spent $167 million on graphite imports, a 34% jump from the previous year. And with the demand for electric vehicles and renewable energy storage soaring, graphite’s role in lithium-ion batteries is indispensable. Vedanta Aluminium’s technology promises to reduce this import reliance significantly.

But Vedanta Aluminium isn’t stopping there. Their collaboration with other aluminium giants, eminent CSIR Laboratories, JNARDDC and  backed by Niti Aayog, to extract Rare Earth Oxides from bauxite residue is expected to be another game-changer. These oxides notably scandium is crucial for creating cutting-edge aluminium alloys for sectors like defence, aerospace, maritime, and automotive, where India currently lacks primary sources of the minerals. By harnessing these secondary resources, Vedanta Aluminium is pushing innovation while propelling India towards self-sufficiency. As the Government of India emphasizes the strategic importance of Critical Minerals in realizing the vision of an Atmanirbhar Bharat (self-reliant India) and accelerating decarbonization efforts, it becomes imperative to chart a clear roadmap with identified stakeholders. Vedanta Aluminium’s trailblazing efforts in R&D exemplify a proactive approach towards reducing import dependence, fostering innovation, and bolstering India’s position in the global economic landscape.

As the planet reaches unprecedented climatic milestones, 2023 has now been recorded as the warmest year on Earth. The impacts of climate change are increasingly undeniable, and the urgency for decarbonization efforts by governments and corporations has never been more critical.

A recent study from Imperial College London suggests that without drastic reductions in carbon emissions, we have only a 50% chance of limiting global warming to 1.5°C by 2030. This stark reality underlines the pressing need to accelerate efforts to reduce our carbon footprint.

The Demand for Green Metals in Clean Technology

Meeting our global climate goals requires a vast supply of minerals essential for green technologies, from electric vehicles (EVs) to renewable energy. The International Energy Agency (IEA) reports that EVs, which rely on battery-heavy systems, require up to 173 kg more minerals—like nickel, zinc, and copper—than traditional gasoline cars. The boom in green technology is driving demand for critical minerals, highlighting the need to rapidly scale up mining operations.

Government policies around the world are fostering this growth in clean technology. For example, India’s “Faster Adoption and Manufacture of Hybrid and Electric Vehicles” initiative has been pivotal in encouraging EV and hybrid vehicle purchases, fueling an impressive 60% increase in global EV sales in 2022 alone. The demand for green technologies is expected to keep rising as government support and consumer demand grow.

Scaling Up for the Future: The Critical Role of Metals in Net Zero Goals

Transitioning to renewable energy and clean technology will require vast quantities of metals. The IEA projects that demand for critical metals like copper and aluminum will surge by up to 400% by 2040. To achieve net zero targets, we need 9.7 million metric tons of new copper over the next decade, and annual aluminum demand could rise to as high as 16 million metric tons by 2040.

However, current mining production cannot keep pace with projected demand. A recent report by McKinsey indicates a significant gap between future demand and available supply for key minerals, such as copper and nickel, underscoring the need to boost production to meet our climate commitments.

Navigating Regulatory Challenges

Despite the shared global goal of combating climate change, regulatory policies remain fragmented, creating supply chain challenges for critical minerals. The U.S. Inflation Reduction Act, Australia’s Critical Minerals Strategy, and the European Union’s Green Deal Industrial Plan are just a few examples of policies that illustrate the fragmented regulatory landscape. The IEA has cataloged nearly 200 policies worldwide, with over 100 enacted in the last few years, many of which include restrictions on the import and export of critical minerals.

This complex regulatory environment underscores the need for cooperative efforts among governments, mining companies, and industries to ensure a stable supply of minerals for green technologies. This collaboration is essential to achieve our climate goals while navigating a fragmented policy landscape.

India’s Commitment to Sustainable Growth

India, while home to 17% of the world’s population, contributes less than 4% of global emissions. Guided by the principle of “One Earth, One Family, One Future,” India is committed to balancing economic growth with environmental responsibility. India’s focus on energy transition and sustainable resource use highlights its leadership in tackling climate change and minimizing emissions.

Towards Sustainable Mining

To protect our planet, mining processes must undergo significant transformation. Decarbonizing the mining industry is crucial to deliver the minerals needed for a green transition without compromising on environmental, social, and governance (ESG) standards. As UN Secretary-General António Guterres emphasized, this energy transition must be “sustainable, fair, and just.”

The industry’s commitment to high environmental standards is non-negotiable, as mining companies and governments must work together to protect local communities and respect their needs. Public-private partnerships, like India’s Green Credit initiative, demonstrate innovative approaches to fostering sustainable practices in mining, from extraction to distribution.

A Call to Action for a Sustainable Transition

To secure a sustainable future, the mining industry must prioritize sustainability in delivering these essential metals, ensuring that the transition is both efficient and environmentally responsible. By working together, governments, industries, and communities can create a pathway that safeguards our planet for future generations.