Grinding Mills in the Mineral Processing Industry

Grinding mills are part of the comminution process in mineral processing.

MechProTech (MPT) manufactures grinding mills for mineral processing. This article assesses the function of grinding mills and how they work, offering insight into how the grinding process can be optimised. 

Grinding Mills in the Mineral Processing Industry

Grinding mills pulverise and grind ores in mineral processing applications, breaking them down into fine particles to facilitate the extraction of valuable minerals.

MPT offers a diverse range of grinding mills designed to meet the varied needs of our clients. The MPT equipment range ensures optimised performance and efficiency across all operations.

The General Function of Grinding Mills

A grinding mill grinds and blends materials for various applications.

Appearance of a Grinding Mill

Grinding mills come in various designs and sizes, from small laboratory models to large industrial units.

• The mill typically consists of a large cylindrical shell made of steel or other durable materials, lined with abrasion-resistant materials to protect against wear and tear.
• Inside the shell, the grinding media, usually steel or ceramic balls, rods, or pebbles, vary in size and quantity depending on the milling process.
• The cylinder is mounted on bearings and rotates around its axis, either by an external motor or gears.
• The cylinder features openings at both ends – an inlet for feeding materials and an outlet for discharging the ground material.

How Does a Grinding Mill Work?

Grinding mills operate on the principle of impact and attrition.

Grinding media is added and repeatedly dropped on the material that needs to be ground as the mill rotates. This impact reduces the material’s size while it continuously rolls and slides against the grinding media, resulting in the material being further ground into finer particles.

1. Loading the Mill: The mill is loaded with the material to be ground along with the grinding media. The material can be fed into the mill, either wet or dry.
2. Rotating the Mill: Once loaded, the cylindrical shell starts rotating around its horizontal axis. Gears, belts, or direct drives can facilitate this rotation.
3. Grinding Process: As the shell rotates, the grinding media inside is lifted along the rising side of the shell and then drops harshly down, creating an impact. In addition, attrition forces the material to be ground into finer particles.
4. Discharging the Product: Once the material reaches the desired fineness, it is discharged from the mill through the outlet, ready for further processing or use.

Functions of a Grinding Mill

• Rotation and Lifting: The shell’s rotation causes the grinding media to lift along its inner wall until it cascades down due to gravity.
• Impact Zone: As the media falls, it impacts the material at the bottom of the mill, breaking it into smaller pieces.
• Attrition Zone: The rolling and sliding of the media along the sides and bottom of the shell create a grinding action that further reduces the size of the material.

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Applications of Grinding Mills in Mineral Processing

These mills are widely used in grinding various ores and minerals, including gold, copper, iron, and zinc. As previously mentioned, grinding mills are integral to the comminution process, which crushes ores to separate the valuable minerals from the gangue.

Factors That Influence The Efficiency and Optimisation of Grinding Mills:

• the speed of rotation,
• the size of the feed material,
• and the size/density of the grinding media.

A Mill’s Performance can be improved through:

• Adjusting the mill speed
• Ensuring the proper size distribution of the grinding media
• Maintaining an optimal filling level.
• You can implement automated control systems and real-time monitoring with more advanced technologies.

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MechProTech OEM Equipment

MPT is a specialist manufacturer of mineral processing equipment. Our range of grinding mills and ancillary equipment complements our comminution equipment range.

TITAN Grinding Mills

The TITAN Grinding Mills, built on the MPT TITAN™ design, are well-known for their durability and high performance. These mills are gear-driven and modular with self-aligned flanged motors that run on hydrostatic bearings. This sturdy design guarantees reliable operation and a long service life, even in the most challenging conditions.

Key Features of TITAN Grinding Mills:

• Gear-Driven System: Provides maximum torque and power transmission for high grinding efficiency.
• Self-Aligned Flanged Motors: Ensures optimal alignment and reduces maintenance requirements.
• Hydrostatic Bearings: Offers superior lubrication and minimises friction, enhancing the lifespan of the mill.

Performance and Efficiency

The TITAN design enables you to run a full process load with a 40% ball charge at 80% of the critical speed, achieving maximum grinding power for every shell size. This design ensures the mills operate at peak efficiency, delivering optimal particle size reduction and throughput.

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Standard Mill Types Available

MechProTech offers a range of standard mill types to suit various applications and processing requirements:

• Overflow Ball Mills: For a finer grind. They allow the ground material to overflow out of the mill.
• Grated Ball Mills: Designed to discharge material through slots or grates, providing efficient grinding and separation.
• Peripheral Discharge Ball Mills: Features discharge ports around its periphery, allowing quick removal of the ground material.
• Rod Mills: Long rods are used for grinding media, which is ideal for coarse grinding applications.

Integration with TITAN Automatic Ball Charger

To further enhance the performance of the TITAN Grinding Mills, MechProTech offers the TITAN Automatic Ball Charger.

This automated grinding media feeder is designed to maintain the optimal grinding media load in the mill, ensuring consistent power draw and efficient operation. The PLC (Programmable Logic Controllers) is programmed to monitor the grinding mill’s power draw, automatically dispensing grinding media when needed to maintain the desired load and optimise milling conditions.

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Enhance Your Operations With MechProTech’s Comminution Equipment

Grinding Mill equipment, such as MechProTech’s TITAN Grinding Mills and TITAN Automatic Ball Charger, can optimise grinding mills’ efficiency and performance, benefiting the process.

Investing in MPT equipment promises to improve your operational efficiency, with our team of experts ready to walk you through it all.

Reach out to our team and find out how we can improve your process.