Electrostatic Separation in Iron Ore Processing: A Revolutionary Approach to Iron Ore Tailings Management

Iron is the second most common element on Earth, comprising nearly 5% of Earth’s crust. Iron ores are rocks and minerals that contain iron, refined through mining and processing. Almost 100% of mined iron ore is used in steel production, making it essential for everything from staples to buildings.

The dry separation industry is fast-growing, developing environmentally friendly methods to contend with the growing risks of iron ore tailings management. Recent high-profile failures of tailing dams and impoundments have generated a strong interest in the industry to find alternative uses for tailings and eliminate high-risk wet tailing storage ponds.

ST Equipment & Technology (STET) is a leader in the water-free minerals separation equipment field. Our groundbreaking electrostatic separation equipment utilizes a dehydrated method of fine iron separation based on electrical conductivity.

What is Iron Ore Beneficiation?

Beneficiation is the term for reducing the size of valuable iron ore particles and separating them from the gangue (unusable minerals), which are then discarded as tailings. There are several different methods of wet and dry separation. The type of beneficiation employed depends on the physical and mineralogical properties specific to each iron ore deposit.

Iron ore processing involves a series of steps to extract and refine iron from its ore deposits. The first stage is mining, where large-scale open-pit or underground operations extract iron ore from the Earth. Once extracted, the ore undergoes crushing and screening to break it into smaller pieces and classify it based on size. Following this, the ore is subjected to various iron ore beneficiation processes such as gravity separation, magnetic separation, and flotation to remove impurities and increase iron content. Magnetic separation is particularly effective in separating iron ore from gangue minerals due to the magnetic properties of iron. However, magnetic separation loses its effectiveness on finer particles, often lost as tailings.

What are the Challenges Associated with Iron Ore Tailings?

Iron ore tailings, which are the byproducts generated during iron ore processing, can pose several environmental and safety challenges. Some of the key problems associated with iron ore tailings include:

  • Environmental Impact: Disposing of large quantities of tailings can lead to environmental degradation. If not managed properly, the release of tailings into water bodies can result in water pollution, affecting aquatic ecosystems and potentially harming wildlife. The fine particles in the tailings can also lead to soil erosion and degradation.
  • Water Contamination: Tailings often contain residual chemicals (like sulfuric acid) and minerals used in the iron ore beneficiation process, which can leach into nearby water sources. This leaching may introduce harmful substances, such as heavy metals, into the water, posing a threat to both aquatic life and human health.
  • Storage and Stability: Managing the storage of large volumes of tailings poses challenges. Tailings dams, where these materials are often stored, must be carefully engineered to ensure stability. Failures of tailings dams can result in catastrophic events as seen in some notable incidents (like El Cobre), causing environmental disasters and endangering nearby communities. Several high-profile tailings dam failures in recent years have resulted in loss of life.
  • Space Requirements: The tailings storage requires a significant land area, which can compete with other land uses. This can lead to deforestation, habitat loss, and displacement of local communities.
  • Long-Term Liability: Tailings’ environmental impact may persist for decades or even centuries. Managing and monitoring these tailings over the long term is essential to prevent ongoing ecological harm.
  • Economic Implications: The cost of managing and mitigating the environmental impact of iron ore tailings can be substantial. Companies and governments must invest in proper tailings management practices to minimize long-term economic and environmental liabilities.

How Does the STET Electrostatic Separation Process Help with Iron Ore Tailings Management?

Electrostatic separation is an industrial process using electrostatic charges to separate large quantities of material particles differentially. It’s most commonly used to sort mineral ore, helping to remove foreign material and leave behind a purified substance. Because STET’s electrostatic separation equipment is uniquely suited to processing fine iron ore minerals, it can drastically reduce the amount of tailings generated during a traditional iron ore processing operation.

What are the Benefits of Electrostatic Separation?

Electrostatic separation is a completely dry processing operation with zero water consumption, which means no energy is expended for pumping, thickening, and drying and no costs from water treatment and disposal. Other benefits of electrostatic separation include lower investment and operating costs and ease of permitting due to its minimized environmental impact. This process requires no chemical additives, further enhancing its environmental benefits.

ST Equipment & Technology (STET) develops and manufactures Tribo electrostatic separators for the fly ash and minerals industry using a proprietary electrostatic separation process developed by an MIT scientist. We’re proud of our unique iron ore beneficiation process, which benefits the mining industry and the environment.

Our specialized separation equipment for fine minerals has developed an impeccable reputation in North America, Europe, and Asia thanks to a dedicated team of experts solving separation challenges for our customers.

Contact us today to learn more.