What Are the Five Key Physical Methods in Mineral Processing?

Mineral processing is the science and technology of separating valuable minerals from gangue. While modern plants rely on advanced machinery, the foundation remains the same: understanding the physical properties of different minerals. Below are the five most important physical mineral processing methods still widely used today.

1.Hand Sorting

Hand sorting, one of the oldest beneficiation methods, separates minerals based on visible differences such as color, luster, or texture. Once performed entirely manually, it is now mostly done using optical and sensor-based equipment, improving accuracy and efficiency.

2. Gravity Separation

Gravity separation takes advantage of density differences between minerals. Early civilizations observed how heavy minerals sank while lighter ones floated in water. Today, advanced equipment such as shaking tables, spiral chutes, and heavy-medium separators achieve precise mineral recovery. Gravity separation is especially important in coal, iron ore, diamond mining, and the pre-concentration of metallic ores.

3. Flotation Separation

Flotation separates minerals according to differences in surface properties. By adding reagents, valuable minerals become hydrophobic and attach to air bubbles, while gangue remains hydrophilic. The floated particles rise to the surface and are collected. This method is indispensable for processing non-ferrous metals, gold, and sulfide ores.

4. Magnetic Separation

Magnetic separation classifies minerals based on magnetic susceptibility. Weak magnetic fields recover strongly magnetic minerals such as magnetite, while strong fields are needed for paramagnetic minerals like wolframite. It is most commonly applied in iron ore beneficiation, tin ore processing, and even non-metallic minerals like sand.

5. High-Voltage Electrical Separation

This method exploits differences in electrical conductivity. Conductive minerals discharge quickly under high voltage, while non-conductive ones retain charge and are separated. It is mainly applied in heavy sand beneficiation, but has strict requirements for ore dryness and low ambient humidity. High operational costs also limit its widespread use.

In practice, two or more of these methods are often combined to achieve the desired concentrate quality. Gravity separation remains the most economical option and often serves as the first step, while flotation, magnetic, or electrical methods are applied for further refinement.

By choosing the right combination of physical methods, mining operations can improve recovery rates, reduce costs, and maximize the economic value of their deposits.