It accepts initial feed sizes of up to 20 mm and can achieve grind sizes down to 15 µm by friction and impact. Hard, brittle or fibrous samples are pulverized in the 150 l drum filled with 80 kg grinding balls. The variable speed of 10 to 50 rpm, different grinding ball sizes and the possibility of long-term grindings of up to 100 h ensure perfect adaption to sample properties as well as reproducible results. A TM 500 foodGrade model featuring a stainless steel 316L drum and the hopper is available for applications where the sample must not be contaminated in any way.
Thanks to the feed hopper and optional separating screen for grinding balls/ sample, operation of the TM 500 and handling of the required 80 kg of grinding balls are particularly ergonomic and simple. The drum is easily emptied by an electronic tilt function. Parameters like grinding time, start delay, or interval mode are selected and stored conveniently via the operating display. Thanks to programmable grinding breaks it is also possible to process heat-sensitive sample materials. Intervals with forwarding and reverse mode combinations are useful to avoid caking effects. For additional safety, the drum mill is equipped with an emergency switch for the instant turn-off.
40 kg (27 l) samples were filled in the drum of the Drum Mill TM 500, and 80 kg (17.6 l) of 20 mm grinding balls were added. The drum mill was operated for several hours at 50 rpm.
The fineness was measured after 2, 4, 6 and 8 h.
2h: D90 = 98 µm
4h: D90 = 37 µm
6h: D90 = 21 µm
8h: D90 = 15 µm
Sample: Gravel 10-15 mm
Feed quantity: 27 l
Grinding balls: 80 kg, 20 mm diameter
Typical Sample Materials
RETSCH 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, hydroxylapatite, kaolin, limestone, 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.
Grinding gentian roots
22 l sample was filled in the drum of the Drum Mill TM 500, 80 kg of 30 mm grinding balls were added. The drum mill was operated for several hours at 50 rpm. The fineness was measured after 1 h.
1h: D90 = 130 µm
The optional separation unit to separate the ground sample from the balls was used.
Used separation grids: 22 mm for 30 mm grinding ball separation in the upper, middle, and lower position.