Magnesium

Magnesium is a lightweight, silvery-white metallic element with the chemical symbol Mg and atomic number 12. It is the eighth most abundant element in the Earth’s crust and the third most abundant element dissolved in seawater, following sodium and chlorine. As one of the alkaline earth metals, magnesium plays a crucial role in both natural processes and modern technological applications. Its combination of lightness, strength, and reactivity has made it indispensable in fields ranging from biological systems to industrial manufacturing, energy production, and consumer goods.

Natural Occurrence and Extraction

Magnesium does not occur freely in nature due to its high reactivity. It is found in various minerals such as dolomite (CaMg(CO₃)₂), magnesite (MgCO₃), and carnallite (KMgCl₃·6H₂O), as well as dissolved in seawater and brine deposits. The two main industrial extraction methods are:

• Electrolysis of molten magnesium chloride (MgCl₂), primarily obtained from seawater.
• Thermal reduction of dolomite using ferrosilicon in the Pidgeon process, particularly common in China.

Magnesium’s production is concentrated in China, Russia, Israel, and the United States, with China accounting for more than 80% of global output.

Physical and Chemical Characteristics

Magnesium is light (density 1.74 g/cm³), ductile, and electrically conductive. It has a melting point of about 650°C and a boiling point of 1,090°C. The metal burns with a bright white flame, forming magnesium oxide (MgO) and magnesium nitride (Mg₃N₂). Its lightness and mechanical strength-to-weight ratio make it highly valuable in industries requiring reduced mass without compromising stability or durability.

Everyday Applications

Magnesium’s ubiquity extends to everyday life, often in ways unnoticed by consumers.

• Nutritional supplements: Magnesium is essential for human health, involved in over 300 biochemical reactions, including energy production, muscle function, and nerve transmission. It is found in dietary sources such as nuts, leafy vegetables, and grains, and is also sold as magnesium citrate or magnesium oxide supplements.
• Pharmaceuticals: Compounds such as magnesium hydroxide (milk of magnesia) and magnesium sulphate (Epsom salt) are used as antacids, laxatives, and muscle relaxants.
• Fireworks and photography: Magnesium’s bright flame makes it ideal for producing white light in fireworks, signal flares, and flash photography.
• Household goods: It is used in certain kitchen utensils, laptop casings, mobile phones, and lightweight consumer products where durability and portability are desirable.

Industrial and Manufacturing Applications

Magnesium is a cornerstone of modern industry, particularly valued for its lightweight structural properties and ability to form high-performance alloys.

• Aerospace and automotive engineering: Magnesium alloys, often combined with aluminium, zinc, and manganese, are used in aircraft components, car bodies, and transmission casings. These alloys reduce fuel consumption by lowering overall weight, thereby improving efficiency and lowering emissions.
• Electronics: Magnesium’s excellent electromagnetic shielding and machinability make it ideal for producing camera bodies, laptops, and mobile phones.
• Construction and machinery: Magnesium oxide and magnesium hydroxide are used in refractory materials, cement formulations, and insulating panels due to their fire resistance and thermal stability.
• Packaging: Magnesium-based alloys are used for lightweight containers and components where corrosion resistance and recyclability are essential.

Role in Energy and Environmental Technologies

Magnesium contributes significantly to advancing energy technologies and sustainability efforts.

• Battery development: Magnesium is being investigated as a safer and more energy-dense alternative to lithium in next-generation rechargeable batteries, offering improved energy capacity and reduced dendrite formation.
• Hydrogen storage: Magnesium hydride (MgH₂) serves as a potential hydrogen storage medium for fuel cells and renewable energy systems due to its high hydrogen content and reversibility.
• Desulphurisation in steel production: Magnesium removes sulphur impurities from molten iron and steel, improving product quality and reducing emissions.
• Environmental protection: Magnesium compounds neutralise acidic waste and treat wastewater by precipitating impurities.

Economic Importance

The magnesium industry plays a pivotal role in the global materials market. With growing demand for lightweight metals in automotive and aerospace sectors, magnesium’s economic significance continues to increase.

• Production and consumption trends: Global production exceeds one million tonnes annually, with China as the dominant producer. The European Union and North America are major consumers, particularly in transportation and electronics industries.
• Market drivers: Demand is propelled by the push for fuel efficiency, carbon emission reduction, and sustainable material development. Magnesium’s recyclability enhances its long-term economic attractiveness.
• Price volatility: Market prices fluctuate with energy costs and geopolitical conditions, as magnesium extraction and refinement are energy-intensive processes.
• Recycling and circular economy: Magnesium is fully recyclable, and recovery from scrap metal reduces energy requirements by nearly 80% compared to primary production.

Medical and Biological Significance

Beyond industrial uses, magnesium holds vital biological importance. It is the fourth most abundant mineral in the human body, necessary for DNA synthesis, nerve transmission, and heart rhythm regulation. Deficiency in magnesium can lead to muscle cramps, fatigue, and cardiovascular issues.
In medical practice, magnesium compounds serve several functions:

• Magnesium sulphate is used in obstetrics to prevent seizures in pre-eclampsia.
• Magnesium hydroxide acts as a gentle antacid and laxative.
• Magnesium chloride is administered to correct magnesium deficiency intravenously.

Its biocompatibility has also led to the development of magnesium-based biodegradable implants, which dissolve safely in the body after healing, reducing the need for secondary surgeries.

Environmental and Safety Considerations

Although magnesium is non-toxic and environmentally benign, its flammability poses handling challenges, particularly in powder or molten form. It burns intensely, and water cannot extinguish a magnesium fire due to hydrogen gas formation. In environmental contexts, magnesium compounds are generally considered safe and non-polluting, and magnesium’s widespread presence in natural systems ensures minimal ecological disruption.
Sustainability efforts focus on reducing the carbon footprint of magnesium production by improving energy efficiency and developing electrolysis powered by renewable energy sources. Research continues into extracting magnesium from seawater and saline lakes in more eco-friendly ways.

Strategic and Future Outlook

Magnesium’s combination of lightness, strength, and versatility ensures its continuing role as a strategic industrial metal. The global shift towards electric vehicles, renewable energy, and lightweight design enhances its economic relevance. Moreover, advances in magnesium battery research and medical materials promise new frontiers of application.
From aircraft frames and automotive components to nutritional supplements and fireproof materials, magnesium underpins modern civilisation in both visible and invisible ways. As industries pursue lighter, stronger, and more sustainable materials, magnesium’s importance will continue to expand, reinforcing its position as one of the most essential elements of the 21st century.