BALL MILLS

BALL MILLS. FROM NANO GRINDING. TO MECHANOCHEMICAL. SYNTHESIS. Mixer Mill MM 500 retsch/mm500. RETSCH introduces the first.

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THE PERFECT BALL MILL FOR EVERY APPLICATION 04 Œ 05 RE-INVENTING BALL MILL TECHNOLOGY MIXER MILL MM 500 06 Œ 09 Dear Readers, Customers and Business Partners,Ball mills are among the most variable and effective tools when it comes to size reduction of hard, brittle or fibrous materials. The variety of grinding modes, usable volumes and available grinding tool materials makes these mills perfectly suited for a vast range of applications Œ from producing nanosized particles to effecting mechanochemical synthesis of two or more materials.That is why RETSCH has developed the widest range of ball mills in the world. On the following pages you will not only read about the different types and models but will also gain insight into application specifics like correct ball fillings or how to go about achieving a particular grind size. Our latest addition to the ball mill range is the Mixer Mill MM 500. This mill is unique as it combines the ease of use of a classic mixer mill with the power and performance of a planetary ball mill. Thanks to a frequency of 35 Hz the MM 500 generates enough crushing power to produce particles in the nanometer range – a unique feature which no other mixer mill in the market offers. We hope you enjoy reading this issue of fithe samplefi!Your Dr. Juergen Pankratz CEO Verder Scientific | EDITORIAL 02 | Ball Mills | www.ret sch.comContent BALL MILLS COLDER THAN ICE CRYOMILL10 Œ 11HOW TO ASCERTAIN CORRECT JAR FILLINGS AND BALL SIZES FOR SUCCESSFUL BALL MILLING 12 Œ 13THE fiALL-ROUNDERfl FOR SMALL QUANTITIES MIXER MILL MM 400 14 Œ 17 THE CLASSIC PULVERIZATION TOOLS PLANETARY BALL MILLS 18 Œ 19FASTER Œ FINER Œ COOLER HIGH-ENERGY BALL MILL E max20 Œ 21PRESERVING CRYSTALLINE STRUCTURE XRD-MILL MCCRONE 22FOR LARGE VOLUMES DRUM MILL TM 30023Visit www.retsch.com/downloads to view a recording of the WEBINAR “USEFUL TIPS FOR EFFICIENT GRINDING PROCESSES IN LABORATORY BALL MILLS” or download our white paper on efficient ball milling. PREMIUM QUALITY MADE IN GERMANY

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[s][%]0 1000 2000 3000 4000100806040200TimeConcentration of reactants 25 Hz 20 Hz 15 Hz 10 Hz | 03 way the energy is supplied. Consequently, the best-known types of reactions are thermal (energy supplied by heating), electrochemical (energy supplied by electrical current) and photochemical (energy supplied by optical waves). A less known form of chemistry is mechanochemistry where the energy is supplied by impact and shearing forces. The 21st century brought with it a growing consciousness of the environmental impact of chemical reactions and chemists started to examine alternatives to solvents, some of them trying to avoid them altogether. Thus, mechanochemistry slowly gained momentum in disciplines like organic chemistry where it was quickly shown that staple reactions like C-C couplings, oxidations, reductions and pericyclic reactions can be transferred into ball mills. Unlike the mortars used in former times, ball mills allow for precise control of the reaction conditions, a wide range of different energy inputs and the possibility to conduct reactions in sealed vessels. Mills typically used for these reactions are planetary ball mills and mixer mills with grinding jars ranging from 2 ml up to 500 ml. The ball size is critical because the balls themselves initiate the reaction and have to create a new reactive surface by removing the reacted layer. If the balls MECHANOCHEMISTRY IN BALL MILLS In the light of sustainability and Green Chemistry, mechanochemistry offers fast reactions in a solvent-free environment. Mass productivities often exceed the solvent-based reaction equivalents and the work-up procedures are generally easier. Hence, mechanochemistry may become the cornerstone of sustainable energy in the future. Author: Dr. Sven Grätz, postdoctoral research associate, Ruhr University Bochum, Germany, Faculty of Chemistry and Biochemistry, Chair in Inorganic Chemistry I, Prof. Borchardt [1] Ma, X., Yuan, W., Bell, S. E., & James, S. L. (2014). Better understanding of mechanochemical reactions: Raman monitoring reveals surprisingly simple ‚pseudo- HOW DOES MECHANOCHEMISTRY WORK? For mechanochemistry, the mode of energy impact seems to play a vital role. Whereas in planetary ball mills shearing is the predominant size reduction principle, it is impact in mixer mills. Beside the type of mill, scientists had to re-evaluate parameters of ficlassicalfl chemical reactions, like concentration and temperature, when transferred to a ball mill, as these are different in the solvent-free environment. Interesting results have been presented by the group of Stuart James [1]. They conducted a chemical reaction at different temperatures and milling frequencies and showed that only the frequency has increase in temperature had no effect. also tend to agglomerate. If the balls are too big, reactions are initiated but the amount of reactive collisions is rather the particle surface, leading to small reaction rates. Suitable balls therefore range from 5 to 15 mm in diameter, offering a good compromise. The jar and ball materials are also very crucial in mechanochemical applications. The material, such as zirconium oxide or stainless steel, must be resistant to the chemicals while being mechanically stable to avoid excessive abrasion. Fig. 1: The rate of reaction shown as unreacted reactant against time at an energy in-in the Mixer Mill MM 400. The rate of reaction increases with the frequency.MECHANOCHEMISTRY |

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Mixer Mill MM 200Mixer Mill MM 400Mixer Mill MM 500CryoMill Planetary Ball Mills PM 100/200/400High Energy Ball Mill EmaxXRD Mill McCroneDrum Mill TM 300Max. sample volume 2 x 10 ml 2 x 20 ml 2 x 45 ml 1 x 20 ml 1 x 220 ml / 2 x 50 ml / 4 x 220 ml 2 x 45 ml 1 x 4 ml 1 x 20 l Available grinding tool materials 66447332Dry grindingWet grindingŒCryogenic grinding ŒŒŒŒNano grinding ŒŒŒŒŒBead beatingŒŒŒŒŒŒMechanochemical processes ŒŒŒŒContinuous cooling (with 5 °C cold water)ŒŒŒŒŒŒŒContinuous cooling at -196 °C with LN 2)ŒŒŒŒŒŒŒHigh-impact pulverization ( with 1 large ball) ŒŒŒŒTime required to produce nano particles ŒŒfast Œmoderate very fast ŒŒLong-term grinding (continuous) ŒŒŒŒŒŒŒGentle grinding with low energy input ŒŒŒŒŒPreservation of crystal sample structure ŒŒŒJars pressure-tight < 5 barŒŒŒJars with integrated safety closure ŒŒŒŒŒŒJars stay clamped in the mill for sub-sampling ŒŒŒŒŒŒŒLegend: Suitable | Œ Not suitable | Suitable to a limited extent see page 14 see page 6 see page 10 see page 18 see page 20 see page 22 see page 23 WIDEST RANGE OF BALL MILLS WORLDWIDE 04 | Ball Mills | www.ret sch.comThe RETSCH ball mill range is the most extensive offering in comprises mixer mills, planetary ball mills, high energy ball mills, XRD mills, and drum mills. Whereas the mixer mills are used for dry/wet/cryogenic grinding and homogenizing small sample volumes, the planetary ball mills meet and exceed all requirements for fast and reproducible grinding of larger volumes down to the submicron range as well as mechanical alloying. The High Energy Ball Mill Emax and the Mixer Mill MM 500 provide grind sizes in the nanometer range in a very short time and are also used for mechanical alloying and mechanochemical applications. The XRD-Mill preserves the crystalline structure of the sample for subsequent XRD analysis. The Drum Mill TM 300 with its ball and rod modules in wet or dry condition. Whatever your requirements may be Œ RETSCH has the perfect ball mill for your application! THE PERFECT BALL MILL FOR EVERY APPLICATION | OVERVIEW PAGE - 5 ============ Mixer Mill MM 200Mixer Mill MM 400Mixer Mill MM 500CryoMill Planetary Ball Mills PM 100/200/400High Energy Ball Mill EmaxXRD Mill McCroneDrum Mill TM 300Max. sample volume 2 x 10 ml 2 x 20 ml 2 x 45 ml 1 x 20 ml 1 x 220 ml / 2 x 50 ml / 4 x 220 ml 2 x 45 ml 1 x 4 ml 1 x 20 l Available grinding tool materials 66447332Dry grindingWet grindingŒCryogenic grinding ŒŒŒŒNano grinding ŒŒŒŒŒBead beatingŒŒŒŒŒŒMechanochemical processes ŒŒŒŒContinuous cooling (with 5 °C cold water)ŒŒŒŒŒŒŒContinuous cooling at -196 °C with LN 2)ŒŒŒŒŒŒŒHigh-impact pulverization ( with 1 large ball) ŒŒŒŒTime required to produce nano particles ŒŒfast Œmoderate very fast ŒŒLong-term grinding (continuous) ŒŒŒŒŒŒŒGentle grinding with low energy input ŒŒŒŒŒPreservation of crystal sample structure ŒŒŒJars pressure-tight < 5 barŒŒŒJars with integrated safety closure ŒŒŒŒŒŒJars stay clamped in the mill for sub-sampling ŒŒŒŒŒŒŒLegend: Suitable | Œ Not suitable | Suitable to a limited extent see page 14 see page 6 see page 10 see page 18 see page 20 see page 22 see page 23 | 05DRY GRINDING WET GRINDING CRYOGENIC GRINDING NANO GRINDING BEAD BEATING MECHANOCHEMISTRY MIXING OVERVIEW | PAGE - 8 ============ NANO GRINDING WITHOUT COOLING BREAKS dry, wet or cryogenic mode, it stands out from the rest due to its suit -ability for new types of applications, These include colloidal grinding of samples down to < 100 nm but also mechanochemical applications, not possible with a mixer mill so far. When samples need to be pulverized over a longer period of time to obtain particle sizes in the nanometer range, the MM 500 allows for substantial time savings compared to planetary ball mills due to the advantage over planetary ball mills which generate too much heat to be operated without interruptions. Fig. 3: The innovative Screw-Lock grinding jars are easy to handle and clamping is a matter of seconds. The jars remain clamped in the mill for extraction of a sub-sample or a quick visual check of the sample[min]Fig. 2 shows the development of particle fineness and temperature during wet grinding. The MM 500 was operated without cooling breaks, the total process time therefore equals the net grinding time. The MM 500 produced particles of cooling breaks (1 h net grinding) were required in the Benchmark Planetary Ball [µm][°C]0 30 60 90 120 150 180 210 240 270 3005432101009080706050403020100Total processing timeParticle size d 90Temperature Processing time and temperature for production of nano particles of aluminum oxide[min]08 | Ball Mills | www.ret sch.comEXAMPLE: CRYOGENIC GRINDING OF RUBBER For cryogenic applications, where the sample is embrittled with liquid nitrogen to improve its breaking behavior, the MM 500 produces mills with 30 Hz. Another advantage of the MM 500 are the larger jar sizes allowing for more sample quantity compared to those used in other mixer mills. Example: Cryogenic grinding of rubber granulate in the MM 500 for 8 min with in -termediate cooling every 2 min. Compared to the results in a mixer mill with 30 Hz, the 8 MM INITIAL SIZE0.7 MM FINAL FINENESSOPERATING CONVENIENCE 2.0 The MM 500 provides maximum opera -tional convenience. The user can store up to 12 standard operation procedures (SOPs) via the large 4.3-inch touch display. Grinding processes > 8 h can be realized by using program cycles of which 4 may be stored . Here, two parameter sets are combined and repeated up to 99 times, increasing the total processing time up to 99 h. With the new optional RETSCH App, the user can control the mill via smart phone or tablet, create application routines, access the RETSCH application database or get in touch with the RETSCH service team. The innovative Screw-Lock grinding jars, which are pressure-tight up to 5 bar, are safe and easy to handle. The lid is simply screwed tight and the jar is inserted in the clamping system; it may even remain there for extraction of a sub-sample or a quick visual check. The clamping procedure is more user-friendly compared to other ball mills. | MIXER MILL MM 500 Fineness Benchmark Planetary Ball Mill, 1100 min-1 Temperature Benchmark Planetary Ball Mill, 1100 min -1 Fineness MM 500 35 Hz Temperature MM 500 35 Hz

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The jar design ensures optimum utiliza -tion of the usable volume (Fig. 4). This is an advantage over the jars of classic mixer mills where the lid forms part of the jar volume (Fig. 5). Filling 60 % of the jar with balls plus sample and liquid, as is required for wet grinding, is very hard to achieve in these jars. Moreover, jar volume is not part of the lid. The new MM 500 is the perfect combination of a classic mixer mill and a planetary ball mill. On the one hand, it achieves excellent grinding results within a few minutes, on the other hand, it is powerful and robust enough to carry out long-term grindings in the nanometer range or mechanochemical processes. On top of that, uncomplicated handling ensures safe operation. RANGE OF SCREW-LOCK GRINDING JARS Volume [ml] Stainless steelHardened steelZirconium oxide Tungsten carbide5080125 | 09FLAT LID, 0 % VOLUME; 100 % VOLUME IN THE JARFill in fienoughfl fibrous sample 60 % balls for wet grinding + sample + liquid 33 % VOLUME IN THE LID; 67 % VOLUME IN THE JARFibrous sample spills over 60 % balls for wet grinding + sample + liquid not possibleSCREW-LOCK GRINDING JARS ALLOW FOR USE OF FULL VOLUME Fig. 6: The Screw-Lock grinding jars are available in 4 different materials Screw-Lock grinding jar for MM 500 Standard grinding jar for MM 400MIXER MILL MM 500 |

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Not all sample materials can be pulver -ized at room temperature. For ductile and elastic materials cryogenic grind -ing is the only way to achieve the grind sizes required for subsequent analysis. Through cooling with liquid nitrogen to -196 °C, the sample material is embrit -tled to break more easily. Moreover, vol -atile substances are preserved and can degradation is further prevented by cooling the sample before and during grinding. RETSCH™s CryoMill is the per -fect solution for grinding these samples COLDER THAN ICE CRYOMILL10 | Ball Mills | www.ret sch.comCRYOGENIC GRINDING DRY GRINDING WET GRINDING BEAT BEATING MIXING | CRYOMILL

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AUTOFILL SYSTEM ENSURES USER SAFETY One particular advantage of the CryoMill is the high operating safety, as the user never comes in contact with the liquid nitrogen. The supply controlled by a temperature sensor so that LN2 is always provided in the exact amount that is needed to keep the temperature at -196 °C. The automatic cooling system guarantees that the grinding process will not start before the sample is thoroughly cooled Œ this reduces consumption and guarantees reproducible grinding results. With a frequency of 30 Hz, the mill grinds a variety of materials very effectively within a few minutes. In order to ensure the best possi -ble adaptation to different samples, pre-cooling, grinding time, and inter -vals are freely programmable. During pre-cooling or interval times, the grinding jar is slowly moved at 5 Hz, keeping the grinding ball permanently in motion to prevent it from freezing and sticking in humid samples. COLDER THAN ICE CRYOMILL | 11APPLICATION EXAMPLES CRYOMILL SampleGrinding jar size Grinding ball size MaterialSample amount Grinding timeFinal Rubber50 ml 1 x 25 mm stainless steel 6 g 2 min < 400 µm Textile50 ml 1 x 25 mm stainless steel 2 g 4 min < 500 µm Hair25 ml 6 x 10 mm stainless steel 1 g 4 min < 200 µm PET Granulate50 ml 1 x 25 mm stainless steel 3 g 4 min < 300 µm PULVERIZATION IN THE CRYOMILL TO 200 µM PVC SAMPLE AFTER PRE-CUTTING IN A CUTTING MILL SM 300Diethylhexyl phthalate (DEHP) is widely used as a softener to make poly - sheathing or PVC hoses. In products like children™s toys, however, its use is forbidden as it is regarded to have a harmful effect on fertility and is clas - critical softeners need to be analyzed. Prior to analysis, a one- or two-step sample preparation is required, depending on whether the sample size EXAMPLE: CRYOGENIC GRINDING OF PVC calls for pre-cutting. Larger samples of PVC can be pre-cut in a Cutting Mill SM 300 using a 6-disc or a parallel-section rotor and a 6 mm bottom sieve. The granulate resulting from this step can now be pulverized in the CryoMill. Usually, the 50 ml stainless steel grinding jar with one large 25 mm grinding ball, also stainless steel, is suitable to grind about 6 g plastic material. After 90 = 200 µm.CRYOMILL | 322 KB – 24 Pages