Disc Mill

What is the Disc Mill?

A disc mill grinds material between rotating discs to give a reproducible particle size. It is widely used to prepare pressed powders for X-ray fluorescence and other analyses requiring consistent grinding in the laboratory.

Overview

A disc mill presses the sample between two discs, one of which rotates, so the material is reduced by friction and compression as it moves from the centre to the rim. The gap between the discs sets the final particle size, which can be as fine as a few tens of micrometres, and the discs are made from hardened steel, tungsten carbide, zirconia or agate to suit hardness and contamination limits. Vibratory versions shake a ring and puck inside a sealed dish, which is convenient for small samples. The reproducible particle size makes disc mills a standard choice for preparing powder for X-ray fluorescence and diffraction analysis.

How does it work?

Mills reduce particle size by moving grinding media or tools against the sample. A ball mill rotates a jar containing balls, so the sample is ground by cascading impact and friction. A planetary ball mill rotates jars on a sun wheel in the opposite direction, generating high centrifugal energy and fast, fine grinding. A disc mill presses material between discs, a hammer mill strikes it with swinging hammers against a screen, and a jet mill accelerates particles in a gas stream so they break by inter-particle collision without contact with grinding media. The achievable fineness depends on the energy applied, the grinding time and the material, and contamination depends on the tool and jar materials.

What are the key features?

• Rotating discs for friction grinding
• Micrometric gap adjustment
• Disc materials for hardness and cleanliness
• Vibratory ring and puck version available
• Reproducible size for X-ray analysis

What are the technical specifications?

A typical disc mill configuration offers final particle size of Down to 20 µm, max feed size of 15 mm, throughput of Up to 100 kg/h, disc diameter of 200 mm, disc material of Tungsten carbide or agate and gap adjustment of Micrometric. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Disc Mill is used in X-ray fluorescence sample preparation, ore and mineral grinding, cement and slag preparation and ceramic raw material milling. Across the wider Mills class, laboratories also deploy it for X-ray fluorescence and diffraction sample preparation, mineral, ore and cement fine grinding and pharmaceutical and chemical powder milling.

Which standards and certifications apply?

Relevant standards and methods include ISO 3310-1, ASTM E11, ISO 2591-1, EPA 3050B and IEC 61010-1. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Match the jar and ball materials to the sample and the analytes of interest: agate for clean grinding, zirconia and tungsten carbide for harder samples, and stainless steel for general work. Do not exceed the recommended fill, since too much sample or too few balls reduces efficiency, while too many balls leave no space for movement. Grind in intervals to limit heating, which can change the sample or lose volatiles. Clean jars between samples and check wear, since worn media contaminate and no longer transfer energy efficiently. Verify particle size by sieving or laser diffraction, and follow the safety and guarding requirements for the equipment.

How do I select the right Disc Mill?

Choose a disc mill when a reproducible particle size is required for analysis. Confirm the achievable size meets the method, the disc material suits the sample hardness and trace-element limits, and the throughput matches the workload. Vibratory ring and puck versions suit small, high-value samples.

How does it compare with other Mills variants?

Choose a mill according to the required final particle size and the sample hardness. A planetary ball mill reaches very fine sizes quickly and suits hard and brittle material; a standard ball mill suits larger batches and gentler grinding; a disc mill gives reproducible size for X-ray analysis; a hammer mill handles medium-hard brittle samples at higher throughput; and a jet mill gives very fine, contamination-free powder without grinding media. Confirm the final size range, batch capacity and jar or tool materials, and choose a material that does not introduce the elements being analyzed. Consider whether wet or dry grinding, and inert or cryogenic conditions, are needed.