GRINDING & MILLING

TM 300.
Drum Mill.

The TM 300 Drum Mill is utilized for preparing granules and powders through a grinding process conducted in either dry or wet conditions. This versatile grinder can function as either a Ball or a Rod Mill by employing the corresponding module. To ensure an efficient grinding process, it is essential to use a sufficient number of balls or rods. Depending on the sample material, a final fineness below 20 microns can be achieved.

Discuss this product Technical information

RETSCH TM 300 Drum Mill for grinding larger batches of samples; with accessories

RETSCH TM 300 Drum Mill for grinding larger batches of samples; inside the instrument grinding drum with grinding balls

RETSCH TM 300 Drum Mill for grinding larger batches of samples; close-up of the instrument grinding drum

Product and configuration photographs. Select an image to enlarge.

Material feed size< 20 mm used as Bond Index Tester: < 3.35 mm with ball module / 12.50 mm with rod module

Final fineness< 20 µm used as Bond Index Tester: < 100 µm with ball module / 2,100 µm with rod module

Batch size / feed quantityminimum 1 l / maximum 9 l used as Bond Index Tester: min. 15 kg with ball module / min. 20 kg with rod module

Rotation speed1 – 80 min-1 used as Bond Index Tester: 70 min-1 with ball module / 46 min-1 with rod module

THE PRODUCT IN FOCUS

Model overview

The drum mill comprises a gear motor mounted on a robust steel frame, a set of separation grids, and a sample collector. The TM 300 is designed with a yoke and locking mechanism that facilitates easy access to the sample. Cleaning is made convenient by a quick-release locking mechanism, allowing effortless removal of the drum cover.

The TM 300 accepts sample volumes up to 9 l and is therefore also suited for upscaling processes.

PERFORMANCE & OPERATION

Features. Operation. Handling.

BENEFITS AT A GLANCE

Powerful and quick processing of large quantities up to 9 l
Suitable for dry and wet grinding
Standard drum sizes range from 5 l to 43.4 l
Variable speed and reproducible results
Suitable for long term grindings
Ball and rod modules available
Ideal for upscaling tests in mechanochemistry
Perfect seal with single-screw lids

RETSCH TM 300 Drum Mill for grinding larger batches of samples; in its enclosure — TM 300 drum mill in its enclosure

SAFE AND CONVENIENT OPERATION

The TM 300 stands out for its user-friendly features. The easy tilt mechanism facilitates the swift and uncomplicated emptying of the grinding jar. The removable sample collector simplifies the sample retrieval process, making it convenient for operators to access their collected materials.

The solid noise-protection hood contributes to a quieter and more comfortable working environment.

The TM 300 is equipped with an emergency switch, providing a quick and reliable means to halt the milling process in case of unforeseen circumstances, underscoring the commitment to user safety.

The redesigned drums and drum covers of the TM 300 feature improved handling, allowing the lid to be secured with just one screw for a perfect seal, even during wet grinding.

PARAMETER SETTING

Process parameters like grinding time or start/stop are conveniently set via the TM 300’s large display interface. Settings include:

Variable speed from 1 to 80 rpm
Grinding time of up to 99:59:59 h:min:s
Rotation direction, e. g. to reduce caking effects
Programmable interval & break options for temperature-sensitive samples
Delayed start function

RETSCH TM 300 drum mill control display for setting and monitoring sample processing — TM 300 drum mill control display

5 DRUM POSITIONS FOR CONVENIENT HANDLING

The user can set the grinding drums in five different positions which are secured by a screw. This ensures easy filling and emptying of the drum but also improves the mixing and grinding process. The largest rod module of 43.4 l cannot be brought into the mixing position due to lack of space.

Filling Position

Mixing Position

Grinding Position

Emptying Position

Complete Emptying Position

RETSCH TM 300 Drum Mill for grinding larger batches of samples; drum in the filling position — TM 300 drum in the filling position

RETSCH TM 300 Drum Mill for grinding larger batches of samples; drum in the mixing position — TM 300 drum in the mixing position

RETSCH TM 300 Drum Mill for grinding larger batches of samples; drum in the grinding position — TM 300 drum in the grinding position

RETSCH TM 300 Drum Mill for grinding larger batches of samples; drum in the emptying position — TM 300 drum in the emptying position

RETSCH TM 300 Drum Mill for grinding larger batches of samples; drum in the complete-emptying position — TM 300 drum in the complete-emptying position

FUNCTIONAL PRINCIPLE

In a drum mill the sample (usually pre-crushed material) is placed inside the drum with the grinding balls and subjected to external forces.
The Ball Mill is used for fine grinding of solid matter by impact and friction in dry condition. The drum, which contains the sample and grinding balls, rotates around a horizontal axis. Whereas particles break more easily when larger grinding ball diameters are used, smaller diameters lead to a substantially higher final fineness.

The ball and the rod mill basically have the same concept comprising either a 12”x12” jar with grinding balls or a 12”x24” jar with grinding rods.

The jar is attached to a rotating yoke which is driven by a motor and can be placed in three different positions: Upwards for loading, horizontal for grinding, downwards for discharging.

To carry out the Bond Index test the pre-defined number of grinding balls or grinding rods is required. The electronic control integrated in the drive is equipped with an overload protection and permits and controls different speeds.

During the grinding process the difference in speeds between the balls / rods and grinding jar produces an interaction between frictional and impact forces, which releases the required comminution energy. The interplay between these forces produces a very effective degree of size reduction.

APPLICATIONS & METHODS

Build the process around the sample.

SPECIAL APPLICATION: BOND INDEX TEST

Another application area of the TM 300 is Bond Index Testing. The Bond Work Index is used to assess the grinding efficiency and to calculate the necessary grinding power when choosing comminution equipment in the design phase of, for example, a mining plant. Precise determination of BWI is crucial for the accurate design and estimation of costs linked to the comminution process in industries like cement, mining or steel.

Both the Ball Mill and the Rod Mill module can be used for the process. At least 15 to 20 kg sample material is required to simulate a closed grinding circuit.

BALL MILL MODULE

The Ball Mill Work Index (BWI) is used for the range from 2.1 mm down to 100 µm. The sample needs to be pre-crushed to particle sizes as defined below.

Minerals: < 3.35 mm and sieved
Drillcore: < 3.35 mm and sieved
Half Drillcore: < 3.35 mm and sieved

The optimum number of grinding balls is 285. With the ball diameters varying due to wear, the overall number should be adjusted from time to time to ensure a total mass of 20.125 grams.

The grinding jar of the Bond Index Ball Mill measures 12” x 12” and has well-rounded corners.

RETSCH TM 300 Drum Mill for grinding larger batches of samples; drum interior with grinding balls — TM 300 drum interior with grinding balls

ROD MILL MODULE

The Rod Mill Work Index (RWI) is used for particle size determination in a size range from 25 mm down to 2.1 mm. The sample needs to be pre-crushed to particle sizes as defined below.

Minerals: < 12.50 mm and sieved
Drillcore: < 12.50 mm and sieved
Half a drillcore: < 12.50 mm and sieved

The grinding jar for the Bond Index Rod Mill is 12″ x 24″ in size and has a wave-shaped design.

THE SOLUTION FOR EFFICIENT AND SUSTAINABLE CO-CRYSTAL SYNTHESIS

The TM 300 is capable of meeting the demands of modern pharmaceutical manufacturing. This can be demonstrated by the example of the mechanochemical synthesis of rac-Ibuprofen:Nicotinamide co-crystals. The TM 300 is an environmentally friendly alternative to conventional solution-based methods. In just 90 minutes, 3.2 kg of co-crystals with a yield of 99 % were produced, using only minimal amounts of solvent in the so-called liquid assisted grinding (LAG) process. This reduces energy consumption compared to conventional methods and drastically minimizes environmental impact.

Conversion of rac-IBU. Blue plot: neat grinding approach with addition of 10 kg of balls (d = 10 mm) after 270 min and 10 kg of balls (d = 30 mm) after 360 min; addition of LAG additive EtOH after 510 min. Orange plot: LAG-assisted approach with EtOH added prior to the reaction and 20 kg balls 10 mm.

Results presented by the research group of Michael Felderhoff [1]

TM 300 enables mechanochemical processes to be carried out on a kilogram scale, opening up new possibilities for sustainable industrial manufacturing processes. Particularly interesting is the minimal metal abrasion – the measured values were well below concerning levels and significantly lower than, for example, in eccentric vibratory mills. The table shows the minimal abrasion values in the TM 300 during the test run.

RETSCH TM 300 chart relating drum fill level to grinding-ball quantity

RETSCH TM 300 table of sample-grinding conditions and particle-size results

Setup:

2,03 kg rac IBU; 1,20 kg NIC
10 l drum for wet grinding, 20 kg 10 mm grinding balls stainless steel
LAG Ethanol 0.1 ml/g
60 rpm for 90 min
99 % yield

TYPICAL SAMPLE MATERIALS

drum mills are true allrounders. They homogenize, for example: activated carbon, alloys, bentonite, bones, carbon fibers, catalysts, cellulose, cement clinker, ceramics, chemical products, clay minerals, coal, coke, compost, concrete, electronic scrap, fibers, gypsum, glass, hair, hydroxyl apatite, kaolin, lime stone, metal oxides, minerals, ores, paint and varnish, paper, pharmaceutical products, pigments, plants, polymers, quartz, seeds, semi-precious stones, sewage sludge, slag, soil, tissue, tobacco, waste, wood, etc.

Hard-Brittle: Ceramics

Hard-Brittle: Plastics

Medium-Hard: Soil

Fibrous-Tough: Sawdust

Stone fragments before and after drum milling into a fine sample

Coarse mineral sample before and after drum milling into a fine powder

Soil sample before and after drum milling into a fine powder

Wood chips before and after drum milling into a fine sample

TOOLS & CONFIGURATION

The right tools for the task.

ACCESSORIES FOR EFFECTIVE GRINDING

Catering to various application needs, the TM 300 offers standard grinding drums ranging from 5 to 43.4 liters. This ensures that the mill is adaptable to a wide spectrum of processing tasks.

An optional separation grid provides convenient separation of balls and sample after the grinding process. It is suitable for grinding balls sized 10, 20 or 30 mm. A connection for dust extraction prevents release of dust.

The grinding jar comes equipped with a gasket, ensuring a secure seal for loss-free milling operations. This feature not only enhances the efficiency of the process but also minimizes the risk of material waste.

5 Liter Grinding Drum

21.7-liter Grinding drum

Separation Grid

RETSCH TM 300 Drum Mill for grinding larger batches of samples; with 5 liter drum — TM 300 drum mill with 5 liter drum

RETSCH TM 300 Drum Mill for grinding larger batches of samples; with 21 liter drum — TM 300 drum mill with 21 liter drum

RETSCH Outlet sieve of the TM 300 drum mill for controlling ground-sample discharge size — Outlet sieve of the TM 300 drum mill

DRUM FILLING LEVEL FOR GRINDING BALLS AND RODS

While the maximum sample feed size depends on properties like hardness and breaking behaviour, a particle size of approximately 5 mm is ideal for the TM 300. Larger sizes are acceptable but should not exceed 15 mm. For sample lumps which break very easily or for deagglomeration effects, a feed size between 20 and 30 mm is feasible. For such easy-to-process samples, the sample filling level may be increased to 9 l.

If special drums of stainless steel 1.4404 in sizes 21.7 / 10 / 5 l together with grinding balls of steel 1.4404 are employed, it is possible to carry out wet grinding in the TM 300. The total filling volume for wet grinding may exceed the recommended amount for dry grinding. It may be helpful to use a large number of small grinding balls to increase friction.

RETSCH TM 300 reference table of drum-grinding conditions

TECHNICAL INFORMATION

Specifications & reference data

TECHNICAL DATA

Applications	pulverizing, mixing used as Bond Index Tester: quantification of grindability of ores and minerals
Field of application	agriculture, biology, chemistry, construction materials, engineering / electronics, environment / recycling, geology / metallurgy, glass / ceramics, medicine / pharmaceuticals
Feed material	soft, hard, brittle, fibrous – dry or wet
Size reduction principle	friction
Material feed size*	< 20 mm used as Bond Index Tester: < 3.35 mm with ball module / 12.50 mm with rod module
Final fineness*	< 20 µm used as Bond Index Tester: < 100 µm with ball module / 2,100 µm with rod module
Batch size / feed quantity*	minimum 1 l / maximum 9 l used as Bond Index Tester: min. 15 kg with ball module / min. 20 kg with rod module
Rotation speed	1 – 80 min-1 used as Bond Index Tester: 70 min-1 with ball module / 46 min-1 with rod module
No. of grinding stations	1
Material of grinding tools	hardened steel, stainless steel used as Bond Index Tester: hardened steel
Grinding drum sizes	5 l / 10 l / 21.7 l / 43.3 l used as Bond Index Tester: 21.7 l with ball module / 43.3 l with rod module
Setting of grinding time	digital
Drive	3-phase asynchronous motor with frequency converter
Drive power	0.75 kW
Electrical supply data	different voltages
Power connection	1-phase
Protection code	IP 41
Power consumption	~ 1800 VA
W x H x D closed	1500 x 1200 x 700 mm
Net weight	~ 306 kg
Standards	CE

*depending on feed material and instrument configuration/settings

YOUR MATERIAL. YOUR NEXT STEP.

Put the process
to the material test.

Tell us what you’re processing and what needs to change. We’ll help define the equipment, accessories and a useful trial.

Material and starting particle size
Target fineness and required quantity
Temperature, purity and cleaning requirements

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TM 300.Drum Mill.