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Rivista dell'azienda "il campione" (12)

No. 38
INTRODUCING VERDER SCIENTIFIC DIVISION
No. 36
The Art of Milling - Contemporary Milling Technologies
No. 35
NEW PRODUCTS TRIED AND TESTED
No. 34
PRODUCT NEWS'09
No. 33
SAMPLE PREPARATION IN PRACTICE & NEW RETSCH INSTRUMENTS
No. 32
SAMPLE PREPARATION for Instrumental Analysis
No. 31
Grand Prix Season 2008 & New RETSCH Instruments
No. 30
Mills and Particle Analyzers for Environmental Analysis
No. 29
New Product Generation 2007
No. 28
Think big but grind fine!
No. 25
Retsch presents the new Ultra-Centrifugal Mill ZM 200
No. 24
Anniversary issue of the RETSCH customer magazine 10 years "the sample"

Reports applicativi (40)

Ultrafine Grinding with Laboratory Ball Mills
How are nano particles produced? The “Bottom-Up” method synthesizes particles from atoms or molecules. The “Top-Down” method involves reducing the size of larger particles to nanoscale, for example with laboratory mills. Due to their significantly enlarged surface in relation to the volume, small particles are drawn to each other by their electrostatic charges. Nano particles are produced by colloidal grinding which involves dispersion of the particles in liquid to neutralize the surface charges. Both water and alcohol can be used as dispersion medium, depending on the sample material. Factors such as energy input and size reduction principle make ball mills the best choice for the production of nanoparticles.
Toxic substances in our daily life
Plastic is an inherent part of our everyday lives; it is used in a huge variety of things such as, for example, packaging, furniture, clothing or electronic devices. Though the utility of the material is undoubted, consumers are increasingly unsettled by recurring news about hazardous substances detected in plastics.
Substances such as plasticizers, which are not firmly bound in the material, are absorbed via the skin and can influence the hormonal balance. Plasticizers contained in food packaging, for example, penetrate into the food and thus into the human body when the food is eaten. Plasticizers in toys are a particularly serious problem; children tend to take toys into their mouths thus absorbing the dangerous chemicals.  Equally hazardous are polycyclic aromatic hydrocarbons (PAH). The family of PAH comprises more than 100 compounds most of which have been found to be carcinogenic.
Emax - The Revolution in Ultrafine Grinding
The Emax is an entirely new type of ball mill which was specifically designed by RETSCH for high energy milling. The impressive speed of 2,000 min-1, so far unrivaled in a ball mill, in combination with the special grinding jar design generates a vast amount of size reduction energy. The unique combination of impact, friction and circulating grinding jar movement results in ultrafine particle sizes in the shortest amount of time. Thanks to the new liquid cooling system, excess thermal energy is quickly discharged preventing both sample and mill from overheating, even after long grinding times.
Representative results require adequate sample preparation
The following situation is typical for many production plants: After a routine quality check, the production process is stopped or an already produced batch is suspended, because the analysis results were not within the relevant critical values. But does the tested product really deviate from the specifications? The quality control managers are convinced of this because modern analysis instruments provide results with very low tolerances. The sample in question was tested several times and the result was confirmed. The question is why the product does not match the specifications although the production parameters have not been changed in any way.
The possibility that the tested product is indeed deficient cannot be excluded. However, it is often not the product itself which causes irregular analysis results but a lack of understanding of the steps which come before the analysis.
Outdoor clothing: Pure nature or traces of poison?
Outdoor activities such as hiking, biking or climbing are very popular. As a result, the textile industry offers a huge variety of functional outdoor clothing made from synthetic high-tech materials which are wind- and waterproof as well as breathable. In 2013 Greenpeace published a study proving that hazardous substances such as perfluorinated and polyfluorinated chemicals (PFC) were used in weatherproof clothing as protection against water or dirt. This article describes the sample preparation process with cutting mills and cryogenic mills of high-tech fibres.
Sieving of agglomerating powders with the air jet sieving machine AS 200 jet
Air jet sieving is usually the method of choice for dry sieving of materials with particle sizes below 40 microns. However, it is also a faster alternative to vibratory sieving of materials of up to 250 microns.
Air Jet Sieving of Bulk Materials
Particle size analysis and particle size distribution are important criteria for the quality  control of bulk materials. In a running production process, the results of a quality check must be available quickly to allow for immediate adjustment of the production parameters. Depending on the expected particle size and sample volume, different sieving methods and sieving machines are suitable for analysis. The method used for particle size analysis is primarily determined by the fineness of the material to be sieved. For dry sieving of samples with particle sizes below 40 microns, air jet sieving is the method of choice.
Representative Analysis Results Require Adequate Sample Preparation
A faultless and comparable analysis is closely linked to an accurate sample handling. Only a sample representative of the initial material can provide meaningful analysis results. Rotating dividers and rotary tube dividers are an important means to ensure the representativeness of a sample and thus the reproducibility of the analysis. Correct sample handling consequently minimizes the probability of a production stop due to incorrect analysis results. Thus correct sample handling is the key to effective quality control.
CryoMill - Cryogenic grinding was never more convenient or efficient
Some sample materials have properties which make size reduction at ambient temperature impossible. If, for example, very elastic materials need to be ground or volatile components have to be preserved for further analysis, it is essential to carry out cryogenic grinding. The use of liquid nitrogen helps to embrittle the sample, thus improving its breaking properties, and preventing volatile substances from escaping due to the frictional heat produced by the grinding process.
Secondary fuels – Energy for the cement industry
Due to decreasing resources and increasing market prices for primary fuels like oil, gas or coal, it is paramount for the cement industry to search for alternative energy sources. With regard to the CO2 emissions trading, a switch to energy sources which have a neutral CO2 balance can be rather profitable. Usually, these are non-fossil fuels. Industries with high energy consumption have made increasing use of alternative fuels during the last years. Accordingly, the use of so called secondary fuels (also waste derived fuels/wdf or refuse derived fuels/rdf) has gained importance. These are mostly combustible fractions of domestic or industrial waste which cannot be recycled.
Powerful Cutting Mill
The SM 300 excels especially in the tough jobs where other cutting mills fail. It has a freely selectable speed range from 700 to 3,000 rpm with high torque. The mill is convenient to operate and easy to clean. Reliable and extremely efficient sample preparation in the laboratory is now guaranteed with the SM 300.
Plastic - one material with many variations
Thanks to the almost unlimited variety of plastics, their fields of application are huge. Abbreviations such as PE, PET, PC, PP , PBT or ABS not only describe a simple material but a whole class of products with many different characteristics. Depending on the intended use, plastic needs to be, for example, impact-resistant, breakproof, heat-resistant or solvent-resistant.
Preparation of Elastic Plastics for the Detection of PAH
Polycyclic aromatic hydrocarbons, short PAH, are usually a by-product of combustion and can be found, for example, in cigarette smoke or oil-based products. Mineral oil containing PAH is often used in rubber products as plasticizer, especially in black-coloured products such as car tyres, rubber grips of tools or rubber shoe soles. It was discovered that some polycyclic aromatic hydrocarbons are carcinogenic, so that maximum permissible values have been determined for the concentration of PAH in consumer products.
Size reduction of elastic plastics with volatile components
Neutral-to-analysis sample preparation for the detection of PAH and phthalates
Using the CryoMill for samples with volatile substances
For the size reduction of many materials it is more suitable to use a cryogenic mill than a laboratory mill which operates at room temperature. The sample is embrittled by liquid nitrogen which improves its breaking behavior when submitted to impact, pressure and friction; moreover, volatile components of the sample are preserved. The RETSCH CryoMill is not only the most modern and safest cryogenic mill in the market, it also provides excellent grinding results.
Cutting Mill SM 300 - Refinement of a well-proven grinding principle
Cutting mills are used in many different areas of sample preparation for subsequent analyses. Typical applications include the size reduction of secondary fuels, the processing of biomass for renewable energy research, the control of products in the context of RoHS and WEEE regulations or the recovery of precious metals – the variety of sample materials is huge.
Sample Preparation for XRF Analysis
From sample to pellet
Renewable raw materials are gaining ground
The representative sample preparation of plants requires experience
Traces of Heavy Metals in Toys
From Size Reduction to Analysis
Efficient Grinding at –196 °C
RETSCH’s New CryoMill for Safe and Reproducible Grinding with Liquid Nitrogen
Sick with Dolls
Traces of Heavy Metals in Toys
Green Chemistry in the Lab
Mechanochemistry is a very effective method to carry out syntheses without solvents and by-products. The technical literature describes a great number of reactions where a conversion of 100% is achieved. A precondition for the establishment of mechanochemistry in the industrial sector is the availability of suitable laboratory mills. A decisive factor is that – similar to conventional preparative chemistry – ambient parameters such as pressure and temperature can be documented and monitored. The Planetary Ball Mills and Mixer Mills from Retsch fulfill these requirements.
Tracking down hazardous substances (RoHS/WEEE)
Preparing electronic waste for obtaining representative analytical samples.
A solution for converting an electrical appliance into a meaningful analytical sample is described using a remote-controlled toy car as an example.
Size reduction within the context of sample preparation
In general “size reduction” is taken to mean the disintegration of solid substances by mechanical forces without altering their state.
Sample Preparation of Electronic Scrap in the Context of RoHS and WEEE
Since August 2004 new EU directives for the disposal of used electrical and electronic appliances as well as the restricted use of certain hazardous substances in these devices have become effective.
Consistent Milling on a Nano Scale
Planetary ball mills are helping scientists and engineers advance nanotechnology by providing a consistent way to produce nanoscale powders.
Sample Preparation of Solid Materials for the XRF-analysis
X-Ray fluorescence is one of the most versatile methods to determine elements in a sample. The material is exposed to x-rays that cause each element to emit its own unique fluorescent x-ray. The subsequent analysis of the results is based on comparisons to standard samples with given chemical composition.
Sample Preparation of Plastics for X-Ray-Fluorescence Analysis
The elemental analysis of plastics has become more and more important. EC directive 91/338/EWG regulates the ban of cadmium in PVC, EC directive 94/62/EC defines limits for cadmium, lead, chromium and mercury in packing materials and EC directive 2000/53/EC defines limits for the same elements in end-of-life vehicles. This has created a strong need for a rapid and reliable testing method.
Cryogenic Preparation of Sample Materials
Within the context of sample preparation, size reduction plays an important role as it has a substantial influence on the results of the subsequent analysis. If the particles are too coarse or non-homogeneous the results of the analysis may turn out to be incorrect, especially if there is only a very small amount of sample material which represents the total amount.
Analysis of cadmium in plastics
In recent years, mass media have focused on the topics of the environment and environmental conservation. With the advancement in scientific technology, resource development has progressed.
Kolloidvermahlungen zur Erzeugung von Nanopartikeln
Nanoteilchen, d.h. Partikel mit einem Durchmesser von weniger als 100 Nanometer, werden seit vielen Jahren von Wissenschaftlern erforscht. Zum einen lassen sie sich im „Bottom-up“ Verfahren aus Atomen oder Molekülen synthetisieren. Im “Top-Down“ Verfahren hingegen werden größere Partikel, z.B. mit Hilfe von Labormühlen, zerkleinert. Kleine Partikel weisen durch das extrem vergrößerte Verhältnis von Oberfläche zu Volumen erhöhte Oberflächenladungen auf, so dass die Partikel elektrostatisch zueinander gezogen werden. Daher können Nanopartikel nur durch Nassvermahlung (Kolloidvermahlung) erzeugt werden.
Outdoorbekleidung: Natur pur oder dem Gift auf der Spur?
Freizeitaktivitäten in der Natur wie Wandern, Radfahren oder Klettern erfreuen sich großer Beliebtheit. Die Textilindustrie bietet hierfür eine große Bandbreite an Funktionskleidung aus synthetischen High-Tech Materialien, die in der Regel wind- und wasserfest sind sowie atmungsaktiv. Wie Greenpeace in einer Studie von 2013[1] nachweisen konnte, finden sich in wetterfesten Textilien immer wieder Gefahrstoffe wie per-oder polyfluorierte Chemikalien (PFC), welche z. B. zum Schutz vor Wasser und Schmutz in die Kleidung eingearbeitet werden.
Aufbereitung von PET Preforms zur nachfolgenden Analytik
In der Getränkeindustrie werden die Kunststoffflaschen auf das potentiell krebserregende Acetaldehyd geprüft. Dies erfolgt meist in den Vorstufen der Getränkeflaschen, den so genannten Preforms. Bevor der Nachweis erfolgen kann, muss das Acetaldehyd erst aus der Probe extrahiert werden. Um dies reproduzierbar zu ermöglichen, ist es notwendig, die Probe zunächst zu zerkleinern. Dabei ist zu beachten, dass Acetaldehyd eine sehr leicht flüchtige Substanz ist. Der während der Vermahlung notwendige mechanische Energieeintrag kann zur Erwärmung und damit zur Verdunstung des Acetaldehyds führen. Um diesen Effekt zu verhindern, ist die Kryogenvermahlung die ideale Methode.
Probenvorbereitung für die Analyse von PET Verpackungen
PET Flaschen sind als leichte und stabile Getränkeverpackung beliebt und weit verbreitet. Mineralwasser und andere Getränke in diesen Flaschen können jedoch Spuren der gesundheitsschädlichen Verbindung Acetaldehyd enthalten. Der Stoff wirkt sich schon in geringen Spuren negativ auf die Geschmacksqualität aus. Zur Qualitätssicherung sind daher für Verpackungshersteller und Getränkeabfüller aufwändige quantitative Prüfverfahren erforderlich. Da Acetaldehyd eine leicht flüchtige Verbindung ist, muss eine thermische Belastung der PET Probe im Vorfeld der Analyse in jedem Fall verhindert werden. Die Kryogenvermahlung bei -196 °C ist eine Methode zur schonenden, reproduzierbaren Zerkleinerung elastischer Materialien. Das Verfahren eignet sich für die Probenvorbereitung im Rahmen chromatographischer Routinekontrollen im zertifizierten Prüflabor.
Schnell und schonend zerkleinern
In zahlreichen Labors werden täglich viele unterschiedliche Probenmaterialien aufbereitet. Für die Zerkleinerung von Feststoffproben auf Analysenfeinheit wird eine Mühle benötigt, die nicht nur vielseitig einsetzbar und leicht zu reinigen ist, sondern die auch eine reproduzierbare Probenvorbereitung – und damit zuverlässige Analysenergebnisse - garantiert.
Mit der Ultra-Zentrifugalmühle ZM 200 bietet RETSCH eine Rotormühle an, die nicht nur sehr schnell, sondern auch äußerst materialschonend zerkleinert und, dank einer umfangreichen Zubehörpalette, universell einsetzbar ist. Mit ihrem kraftvollen Powerdrive-Antrieb vermahlt die ZM 200 weiche bis mittelharte und faserige Materialien extrem schnell auf Endfeinheiten bis unter 100 µm und steigert so den Probendurchsatz im Labor.
Zusammenspiel der Kräfte
Planeten-Kugelmühlen ermöglichen mechanisches Legieren dank ihrer hohen Zerkleinerungsenergie

Mechanisch legierte Werkstoffe haben schon längst ihren Einzug in die moderne Werkstofftechnik gehalten. Viele neue Werkstoffe und Werkstoffkomposite wurden in den letzten Jahren durch intensive Forschung entwickelt und werden bereits industriell hergestellt. Mechanisches Legieren ist ein gängiges Verfahren, um Werkstoffpaarungen oder Komposite zu synthetisieren, die auf konventionellem Wege nicht realisierbar wären, wie z. B. das Verbinden von Natur aus unmischbarer Legierungspartner. Das Werkzeug der Wahl dafür sind Planeten-Kugelmühlen.
Herstellung von Nanopartikel mit der Planeten-Kugelmühle
Die Herstellung von Nanopartikeln, deren Größe im Bereich von 1 Mikron und kleiner liegt, ist in vielen technischen Bereichen immer mehr auf dem Vormarsch, denn sie ermöglichen die gezielte Veränderung von Materialeigenschaften.
Die neue Power Generation
Planeten-Kugelmühlen haben seit jeher einen festen Platz in der täglichen Laborpraxis zur Feinzerkleinerung unterschiedlichster Materialien. Neben dem Mischen und Zerkleinern hat sich in den letzten Jahren auch im mechanischen Legieren z.B. thermoelektrischer oder hochkoerzitiver Materialien ein weiteres Anwendungsgebiet ergeben.
Los especial del pigmento
Debido a la ilimitada variedad de colores y texturas que ofrencen los recubrimientos en polvo; muchos de los nuevos recubrimientosde aplicación especifica se crean en el laboratorio en pequeñas cantidades que luego se le envían al cliente para su aplicación y aprobación.
Molienda ultrarrápida y ultrafina
El nuevo molino ultracentrífugo ZM 200 de RETSCH es un molino de rotor no sólo extremadamente rápido y cuidadoso con el material molido, sino también de uso universal gracias a su amplia gama de accesorios.

Referenze in letteratura (1)

  • Chemical activation of MgH2; a new route to superior hydrogen storage materials

    We report the discovery of a new, chemical route for ‘activating’ the hydrogen store MgH2, that results in highly effective hydrogen uptake/release characteristics, comparable to those obtained from mechanically-milled material. Hydrogen is widely regarded as a promising alternative to carbonbased fuels; it can be produced from a variety of renewable resources and, when coupled with fuel cells, offers the prospect of near-zero emission of pollutants and greenhouse gases.1 However, the development of hydrogen as a major energy carrier will require solutions to many scientific and technological challenges. Foremost among these is the issue of hydrogen storage; the lightest of all the chemical elements has an excellent energy content per unit weight, but a low energy content per unit volume.

Comunicati stampa (2)

  • Cyclone Mills

  • Versatile Ultra Centrifugal Mill with New Cyclone

    RETSCH’s powerful and versatile ZM 200 offers the ultimate in performance and operating comfort. It is used for the rapid size reduction of soft to medium-hard and fibrous materials down to 40 microns. Because of the efficient size reduction technique and the comprehensive range of accessories the ZM 200 ensures the gentle preparation of analytical samples in a very short time.
    For applications which require an optimum air throughput (e. g. heat sensitive materials) or if larger sample volumes need to be processed, the use of a cyclone is recommended. RETSCH offers a re-designed cyclone with improved functionalities for collector volumes from 250 ml to 5 liters which adds to the ZM 200’s great flexibility.
    Thanks to the wide range of accessories with different rotors, ring sieves and collectors, the ZM 200 can be easily adapted to suit a wide range of applications such as, for example, heavy-metal-free grinding, size reduction of abrasive materials or processing small volumes up to 20 ml.

Referenze (6)

Test Reports (129)