The MM 500 control is a high energy laboratory ball mill that can be used for dry, wet and cryogenic grinding with a frequency of up to 30 Hz. It is the first mixer mill in the market that allows to monitor and control the temperature of a grinding process.
The temperature area covers a range from -100 to 100 °C. For maximum flexibility, the mill can be operated with various thermal fluids, enabling the use of different tempering devices for cooling or heating. If liquid nitrogen is chosen for cooling, the mill needs to be equipped with the optionally available extension device cryoPad. The innovative cryoPad technology allows to select and control a specific cooling temperature in the range from - 100 to 0 °C for the grinding process.
The cooling and heating of the sample material is realized with the patented concept of thermal plates, making sample cooling with, e. g., open liquid nitrogen baths or dry ice obsolete. For tempering, the grinding jars are simply placed on top of the thermal plates. When the grinding jars come in contact with the thermal plates, heat is effectively transferred from or to the jars via the tempering device. The patented hermetically sealed fluid design allows to operate the mill with different thermal fluids, ensuring a flexible and safe temperature regulation and requiring only minimal effort for the user. Depending on the operational setup that is built up, the temperature of the thermal plates can be set in the range from - 100 to + 100 °C.
To control the temperature of a grinding process, the mill needs to be connected to an external tempering device. Basically, there are two options:
1. Temperature regulation with liquid nitrogen
The mill is operated with liquid nitrogen and connected to a nitrogen tank. In this setup the mill must be extended with the optionally available extension device cryoPad. The patented PID (proportional–integral–derivative) system of the cryoPad controls the flow of liquid nitrogen and herewith the temperature of the thermal plates. In this setup, it is possible to select and maintain the temperature of the thermal plates at a specific value. The desired temperature is adjusted via the touch display and can be selected within a range from - 100 to 0 °C, in steps of 10.
Setup 1: Extension device cryoPad and LN2 tank for the operation with liquid nitrogen.
2. Cooling or heating with a liquid thermal fluid
In this setup, the mill can either be connected to a cryostat, to a chiller or to the water tap. The external tempering device regulates the corresponding thermal fluid to a defined temperature and the thermal fluid transfers this temperature to the thermal plates. As during a grinding process, a significant amount of heat may also develop inside the jar, the temperature of the thermal plates may be manipulated. To sum up, the actual temperature of the thermal plates depends on both, on the temperature of the thermal fluid and on grinding parameters, like frequency, time, jar volume, size of grinding balls. For a maximum control of the grinding process, the actual temperature of the thermal plates is continuously monitored in the touch display.
Setup 2: Operation with an external tempering device; e.g. water tap, chiller or thermostat.
The temperature regulation of the MM 500 control is especially designed for the processing of temperature-sensitive sample materials. Cooling or heating may have different objectives.
Some applications are improved if the sample material is heated up during the process. Examples for heating are:
The required temperatures and the operational setup depend on the specific application.
Some analytes are modified, destroyed or vaporized if the sample material gets too warm. If specific temperature levels are exceeded, the structure of, for example, proteins, pharmaceutical substances or food ingredients may be essentially changed.
By keeping the temperature at a moderate level throughout the grinding process, temperature-sensitive natural substances are physically preserved in their original state for analysis.
Grinding of coffee beans at low temperatures for natural substance analysis.
Temperatures below 0 °C are suitable for the embrittlement and homogenization of for example ductile or sticky food. If heavy-metal-free grinding is required, jars of zirconium oxide or tungsten carbide can be used.
If cooled down to - 100 °C, it is also possible to successfully embrittle some polymers.
Fast milling of black Flurocarbon rubber (FKM) by embrittling the sample in two 125 ml jars at – 100 °C.
If using a chiller, powerful wet grinding can be performed at 30 Hz and below room temperature without considering any cooling breaks.
Particle size and temperature development for TiO2 in a wet grinding process with 30 Hz and 2 x 125 ml jars
By cooling the sample throughout a mechanochemical process, the formation of undesired derivatives can be prevented. It is also possible to apply some heating, for example to initiate chemical reactions and increase product yields.
By keeping the temperature below 0 °C, the formation of non-porous zeolitic metal organic compound is inhibited.
By increasing the temperature during synthesis, the yield of a metal organic compound can be increased. © Stuart James, Queens University Belfast.
Available grinding jar sizes are 50 ml, 80 ml and 125 ml, materials include stainless steel, tungsten carbide and zirconium oxide, ensuring contamination-free sample preparation. Heavy-metal-free grinding is possible, also at -100 °C
RETSCH offers a special aeration lid for the grinding jars designed for applications where a special atmosphere is to be maintained in the ball mill jar.
The GrindControl measures temperature and pressure inside the jar. The system includes a sensor and transmission unit as well as an analysis software.
Simultaneous processing of several small samples is possible with the multi-cavity jars and an adapter for reaction vials. This is a typical requirement, for example, for pharmaceutical, chemical and biochemical applications. The small cavity jars provide new opportunities for mechanochemical research activities involving small amounts of chemicals.
The cavities in the jars have an oval shape which ensures effective mixing. The pouring aids allow for safe sample handling. The multi-cavity jars are made of stainless steel, thus providing effective heat transfer to or from the sample.
The adapter accommodates up to 18 disposable reaction vials of 1.5 or 2.0 ml (e.g. Eppendorf vials) or nine 2.0 ml steel tubes. With its two grinding stations, the MM 500 control mixer mill can now process up to 36 samples in one working run. 2.0 ml steel tubes should be used if samples need to be frozen or heated, as polymeric reaction vessels cannot withstand mechanical load at extreme temperatures. The adapter is made of aluminum so that heat is efficiently transferred to and from the reaction tubes.
Multi-cavity jars of 4 x 10 ml and 2 x 25 ml, made of stainless steel, incl. PTFE pouring aids.
Adapter for 18 x 2 ml safe-lock reaction vials or 9 x 2 ml steel tubes, made of aluminum
As the MM 500 control can be used with or without cooling, the mill offers a wide variety of applications. It can be used to homogenize, for example, waste, soil, chemical products, coated tablets, drugs, ores, grain, tissue, glass, hair, ceramics, bones, plastics, alloys, minerals, oil seeds, plants, sewage sludge, pills, textiles, wool etc.
raisins
coated tablets
polystyrene
soil
To find the best solution for your sample preparation task, visit our application database.
| Applications | mechanochemistry, mechanical alloying, size reduction, mixing, homogenization, cryogenic grinding |
| Field of application | agriculture, biology, chemistry / plastics, construction materials, engineering / electronics, environment / recycling, food, geology / metallurgy, glass / ceramics, medicine / pharmaceuticals |
| Feed material | hard, medium-hard, soft, brittle, elastic, fibrous |
| Size reduction principle | impact, friction |
| Material feed size* | <= 10 mm |
| Final fineness* | ~ 0.1 µm |
| Batch size / feed quantity* | max. 2 x 45 ml |
| Grinding chamber volume | max. 2 x 125 ml |
| No. of grinding stations | 2 |
| Vibrational frequency | 3 - 30 Hz (180 -1800 min-1) |
| Setting of temperature setpoint | digital, 0 ... -100 °C (only with cryoPad) |
| Setting of sample cooling time | digital, 0 ... 60 min (only with cryoPad) |
| Setting of grinding time | digital, 10 s - 8 h |
| Total grinding time | 99 h |
| Storable SOPs | 12 |
| Number of storable cycle programs | 4 (with 99 repeats) |
| Typical mean grinding time | 30 s - 2 min |
| Dry grinding | Yes |
| Wet grinding | Yes |
| Cryogenic grinding | Yes |
| Type of grinding jars | screw-lock jar with integrated safety closure devices, multi cavity jar, adapter for safe-lock reaction vials |
| Material of grinding tools | hardened steel, stainless steel, tungsten carbide, zirconium oxide |
| Grinding jar sizes | 10 ml / 25 ml / 50 ml / 80 ml / 125 ml |
| Electrical supply data | 100-120 V, 50/60 Hz; 200-230 V, 50/60Hz |
| Power connection | 1-phase |
| Protection code | IP 30 |
| Power consumption | 750 W |
| W x H x D closed | 690 x 375 x 585 mm |
| W x H x D closed with cryoPad | 690 x 485 x 585 mm |
| Net weight | ~ 63 kg |
| Standards | CE |
| Connection thread size device input | G 1/4" (inner thread) |
| Connection thread size tubing set | G 3/8" (outer thread) |
| Permissible operating pressure cooling device (provided by customer) | 0 ... 5 bar |
| typical pressure range of continous cooling unit e.g. cryostat | 1 ... 2 bar |
| permissible pressure range of LN2 supply | 1.2 ...1.4 bar |
| Permissible fluids | water, water-glycole mixture, thermal oil, liquid nitrogen |
| Thermal applications | embrittling, cooling, heating, temperature control |
| temperature range of fluids | +100 °C ... -196 °C |
| temperature range of cooling plates | +100 °C ... -100 °C |
| Applications | cryogenic grinding with liquid nitrogen |
| Interface | RS-232 (MM 500 control) |
| Communication connection | via included connection cable |
| Power supply | via external power supply |
| Electrical supply data (input external power supply) | 100-230V, 50/60 Hz |
| External power supply classification | Medical grade isolation level |
| Electrical supply data (input cryoPad) | 24 V, 1 A |
| Accessories | LN2 Autofill 150L, LN2 Autofill 50L |
| LED status light | Yes |
| W x H x D | 670 x 110 x 590 mm |
| Net weight | ~ 26 kg |
| Standards | CE |
| Connection thread size device input | G 1/4" (inner thread) |
| Connection thread size of stainless steel tubing adapter | UNF 3/4" |
| Permissible pressure range of LN2 supply | 1.2 ...1.4 bar |
| Permissible fluids | Liquid nitrogen |
| Emissions | Liquid nitrogen gas, condensation |
| Connection | via included tubing set |
| Exhaust outlet | via included Exhaust adapter and aluminum corrugated tube |
| temperature range of fluids | -196 °C |
| temperature control algorithm | PID temperature control |
| Setting of temperature setpoint | digital, 0 ... -100 °C |
| Setting of sample cooling time | digital, 0 ... 60 min |
The grinding jars of the mixer mill MM 500 control perform radial oscillations in a horizontal position. The inertia of the grinding balls causes them to impact with high energy on the sample material at the rounded ends of the grinding jars and pulverize it. High energy milling is possible by operating at high frequencies up to 30 Hz. The movement of the grinding jars combined with the movement of the balls further causes grinding effects due to friction and additionally result in an effective mixing of the sample. The degree of mixing can be increased even further by using several smaller balls.
