应用报告

辅助 (11)

  • Cement - representative sample preparation is important

    To produce high-quality cement, the mineralogical and chemical composition of raw materials as well as intermediate and finished products has to be determined. At each stage of the production, samples have to be taken, processed and analysed to ensure quality control without gaps. Retsch offers a range of instruments that are used for sample preparation during the complete production process, from the quarrying of the raw materials to the final product. The typical sample preparation process involves preliminary size reduction, sample division and fine size reduction before the sample can be submitted to further analyses....
  • Comparative investigations on spinning rifflers

    The influence of the degree of mixing of the material and the influence of the operating data of the apparatus were investigated in two spinning rifflers.
  • Detection of Mycotoxins in Nuts

    Preliminary and fine size reduction
  • Fine Tuning Sieve Analysis for Accurate Particle Size Measurement

    All to often, this useful method is overlooked. But if followed, these principles deliver accurate and reliable results at an affordable price.
  • Put the squeeze on

    Sieving is cost effective for particle sizes greater than 75 μ, although the technique can be used for some materials of smaller size if the method can be validated. Assuming the relevant standards and clean, wellmaintained equipment that conforms to the standards are used, sieving can provide an accurate and reproducible measure of particle size distribution within a sample.
  • Quality control of coal: The influence of sample preparation on elemental analysis results

    The most common types of coal (lignite, bituminous and anthracite) are distinguished by their different chemical and physical properties. The calorific value of coal can be determined by analyzing its carbon content, for example with combustion analyzers. In addition, efficient management of the desulfurization plant requires control of the sulfur content. Compared to the large amount of coal a typical laboratory sample consists of - a 10 liter bucket or even more - the sample volume required for analysis is fairly low, only approx. 1 g. The standard DIN 51701 defines the sample amount to be tested as this relates to the particle size: The bigger the particles are, the more sample material is required.
  • 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.
  • Representative sample preparation for XRF analysis

    Preparing homogeneous samples by milling
  • Sample Division of Large Volumes

    Representative sampling of large sample volumes is an integral part of the physical and chemical analysis of bulk goods and has a decisive influence on the quality of the results. Extraction of a sample from the bulk is not always carried out in a way to ensure representativeness. This is a widespread flaw in the quality control process with a negative impact on the subsequent analysis results. Therefore, more attention should be paid to the correct sampling procedure. Sample division is often considered as a labor-intensive process which not always leads to representative results. RETSCH provides some convenient solutions which help to improve working conditions and thereby the quality of the sampling process.
  • Sample Preparation and Analysis of Arsenic in Rice

    Considerable care must be taken when analyzing a sample like rice in order to achieve an accurate result. The major source of error when analyzing a bulk material comes not from the analytical measurement itself, but from the sample handling, i.e., sampling, sample division, grinding, digestion, etc.
  • 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.

筛分 (12)

  • 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.
  • Down to the bone

    Use of laboratory grinders for size reduction of human bones and bioceramics

    Bone implants and substances for bone regeneration are used in surgery to replace degenerated bone material by implants or to “re-build” it with specific substances. The material used in implants varies from autogeneic (supplied by the patient) through allogeneic (supplied by a donor) bones to replacement materials such as hydroxylapatite (HA) and tricalcium phosphate (TCP). Bovine bones and corals are used in conjunction with synthetically produced foamed materials to form a basis for the regeneration of bone substance. Various RETSCH mills are suitable for the preliminary and fine grinding of human bones as well as bioceramic materials.
  • Fine Tuning Sieve Analysis for Accurate Particle Size Measurement

    All to often, this useful method is overlooked. But if followed, these principles deliver accurate and reliable results at an affordable price.
  • Measuring Dust - Incoming Inspection with Sieve Analysis

    Graduate student Jennifer Franz has developed a new inspection procedure during her work at the German food producer Lebensgarten GmbH. With the help of sieve analysis the company can now reliably ascertain the fines and dust fractions of incoming cereal flakes; these have a negative influence on the mixing and packaging process of muesli.
  • Particle size - a quality feature

    The determination of the particle size distribution of a product has always been of great significance in food production. Taste, color, solubility or extraction behavior are only a few examples of product properties which are directly influenced by particle size. Traditionally, analytical test sieving provides a quick and simple possibility to characterize the particle size of bulk goods. In the testing laboratory of the St. Petersburg branch of LLC Wrigley RETSCH sieve shakers AS 200 jet and AS 200 control are utilized for particle size analysis of fine powders which are used for chewing gum production.
  • Put the squeeze on

    Sieving is cost effective for particle sizes greater than 75 μ, although the technique can be used for some materials of smaller size if the method can be validated. Assuming the relevant standards and clean, wellmaintained equipment that conforms to the standards are used, sieving can provide an accurate and reproducible measure of particle size distribution within a sample.
  • Renewable energies on the rise

    Sample preparation of vegetable-based raw materials with laboratory mills

    Thanks to the increasing usage of biomass as a source of energy, the analysis of these materials in the context of R&D and quality control gains importance, too. Due to the complex properties of plant materials, adequate sample preparation can be rather a challenge.
  • Reproducible Sieving in the Shortest Possible Time

    Despite the rapid development of modern optical particle measuring techniques, classical sieving analysis is still at the forefront for the practical quality assurance of bulk goods.
  • Separation of large sample volumes with the AS 450 control

    Particle analysis of large quantities of bulk goods is usually done by vibratory sieving. In most vibratory sieve shakers in the market the sieve stack is mounted
    on springs which oscillate vertically. However, to evenly distribute the material
    over the entire sieve surface, the so called 3D vibratory sieving as it is used in the AS 450 control is the most suitable method. This is characterized by a circular
    motion superimposing the vertical throwing motion so that the sample material
    is moved over the whole sieve.
  • 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.
  • Small particles help to preserve the Cologne Cathedral

    The Cologne Cathedral is a venerable old building whose historic substance is preserved by continuing restoration works. Mortar is one of the construction materials that the conservators use for preservation and restoration of the ancient stones. To obtain mortar with optimum quality, the conservators at the cathedral workshop in Cologne use a RETSCH sieve shaker to determine the particle size distribution of the material.
  • The Basic Principles of Sieve Analysis

    Many natural and manufactured materials occur in a disperse form, which means that they consist of differently shaped and sized particles. The particle size distribution, i.e. the number of particles of different sizes, is responsible for important physical and chemical properties.

粉碎 (60)

  • 通过声波显微镜研究纯金属钛粉和钛粉以及铁-铜合金的纳米晶体机械性能

    Determination of mechanical properties of nanocrystalline materials by means of acoustic microscopy : application of pure elements (Fe and Ti) and alloys (Fe-Cu)
  • 使用电泳沉积法研究陶瓷微结构

    Ceramic microstructures by electrophoretic deposition of colloidal suspensions
  • 机械研磨的方法合成纳米晶体Al-Si-Fe-X合金粉末

    Mechanical milling and field assisted sintering consolidation of nanocrystalline Al-Si-Fe-X alloy powder
  • 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.
  • As fine as necessary

    A variety of methods can be used to analyze solid materials. What they all have in common is the necessity to use a representative, homogeneous analysis sample which needs to have a particular fineness, depending on the analytical method used. The size reduction and homogenization of solids is usually carried out with laboratory crushers and grinders.
  • Bigger is not Better

    There is a trend towards smaller samples that have more controlled particle size and yet remain representative of the material being analyzed.
  • Cement - representative sample preparation is important

    To produce high-quality cement, the mineralogical and chemical composition of raw materials as well as intermediate and finished products has to be determined. At each stage of the production, samples have to be taken, processed and analysed to ensure quality control without gaps. Retsch offers a range of instruments that are used for sample preparation during the complete production process, from the quarrying of the raw materials to the final product. The typical sample preparation process involves preliminary size reduction, sample division and fine size reduction before the sample can be submitted to further analyses....
  • Cold, sticky and tough - Cryogenic grinding improves breaking properties

    Sticky, tough or elastic samples are generally difficult to pulverize. Cheese, for example, can be ground with a knife mill but only to a final fineness of about 1 – 2 mm which is not small enough for most analysis techniques. Sweets, on the other hand, often consist of various components like elastic foamy sugar with a sticky, liquid filling. If these types of sample are not embrittled before grinding, they tend to clog the mill. Cryogenic treatment, however, improves the breaking properties of cheese or candy so that even elastic materials can be successfully pulverized.
  • 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.
  • Detection of Mycotoxins in Nuts

    Preliminary and fine size reduction
  • Detection of genetically modified organisms (GMO) in food and feed

    Genetic engineering opens up new possibilities in areas such as medical research, development of alternative fuels or global food supply. It is used to modify the characteristics of plants in order to increase the crop yield, improve defense against predators, pesticides or draught, but also increase concentrations of essential vitamins. However, with regards to food the use of genetic engineering is a fairly controversial issue. Moreover, food and feed stuff are subject to rigorous quality control processes to prevent humans and animals from potential harm.
  • Down to the bone

    Use of laboratory grinders for size reduction of human bones and bioceramics

    Bone implants and substances for bone regeneration are used in surgery to replace degenerated bone material by implants or to “re-build” it with specific substances. The material used in implants varies from autogeneic (supplied by the patient) through allogeneic (supplied by a donor) bones to replacement materials such as hydroxylapatite (HA) and tricalcium phosphate (TCP). Bovine bones and corals are used in conjunction with synthetically produced foamed materials to form a basis for the regeneration of bone substance. Various RETSCH mills are suitable for the preliminary and fine grinding of human bones as well as bioceramic materials.
  • Efficient Grinding at –196 °C

    RETSCH’s New CryoMill for Safe and Reproducible Grinding with Liquid Nitrogen
  • 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.
  • Emax - faster, finer, cooler

    The biggest challenge when developing a high energy ball mill is controlling the temperature. The very high energy produced by ball milling leads to an extreme heat increase inside the grinding jars. RETSCH solved this problem by creating an innovative integrated water-cooling system. Grinding breaks for cooling, which are unavoidable in conventional ball mills even after only 30 minutes grinding at moderate speed, are usually not necessary when using the High Energy Ball Mill Emax.
  • From cacao tree to chocolate bar

    The way from the cacao tree to the chocolate bar is a long one. Due to the many processing stages – harvest, fermentation, drying, cleaning, roasting, pre-crushing and finally grinding the cocoa nibs to liquor from which cocoa powder and cocoa butter are pressed – there may be significant differences in the quality.
  • From muesli to streaky bacon - Complete homogenization of complex samples

    The diversity of foodstuffs with their often very different product properties represents a real challenge for food testing laboratories. Before the actual analysis, the sample materials – which can vary strongly with regards to hardness and moisture – need to be homogenized and reduced to a sufficiently small particle size. RETSCH’s GRINDOMIX knife mills are the ideal tools to meet the complex requirements of the sample preparation of food. The model GM 200 has proven itself for the homogenization of small sample volumes of up to 700 ml. For larger volumes RETSCH offers the GM 300 model with a grinding chamber volume of 5,000 ml.
  • 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.
  • Increasing the development efficiency of ceramic materials

    The development of high-performance ceramics is determined by a large number of influencing factors. In addition to material-specific aspects, such as the chemical purity of the initial raw materials, particle size reproducibility and uniformity of particle morphology, production-specific factors also determine the final properties of ceramics.
  • Mechanical Alloying with High Energy Ball Mill Emax

    Alloys such as amalgam in dental medicine or stainless steel are universally known and used. The traditional way to produce alloys is to fuse the components at very high temperatures. If only small quantities are required or if the alloys cannot be fused by melting mechanical alloying is an alternative. For this application ball mills are ideally suited. They provide a high energy input due to the impact and friction effects which occur during grinding.
  • New Knife Mill Sets Standards

    The so-called QuEChERS method (“quick, easy, cheap, effective, rugged and safe”) has been developed to make sample preparation to pesticide analysis more efficient. Serial tests have proved that the analysis results obtained with the QuEChERS method can easily bear comparison with more common methods, such as DFG S19. To guarantee reproducible analysis results, it is essential to completely homogenize the sample. To make sure the sample preparation is reproducible, the homogenization process needs to be carried out with a laboratory mill.
  • 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.
  • Pesticide analsis of soil - not without sample preparation

    The use of pesticides in agriculture makes it possible to plant extensive mono cultures and often leads to substantial yield increases of food and feed crops. Demand and application have grown steadily over the years, leading to increased contamination of the soil due to the toxic nature of pesticides. Soils save the toxins and their decomposition products so that wildlife is also affected by them. Among the undesired side effects are damages to useful plants and insects like bees. The wind carries pesticides to uncontaminated areas such as fields used for organic farming. Rain also transports the chemicals away from their original area of application to waters and groundwater. Although in most cases the limit values for particular pesticides and their decomposition products are not exceeded, the cumulative effect on humans and animals has not been thoroughly investigated so far. The possible accumulation of pesticides in the food chain could be a source of health hazards; therefore strict quality control of soils is indispensable.
  • 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.
  • 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.
  • Preparation of Soil, Sewage Sludge and Sediment Samples in a Wastewater Treatment Laboratory

    The preparation of a mixture of organic and inorganic samples holds some difficulties: whereas sand, clay and stones can usually be ground to homogeneous samples with suitable laboratory mills, the high energy input can cause samples with organic components such as fat or starch to cake. Carsten Bunn, a laboratory technician at the waste water treatment laboratory BRW, has to deal with this problem every day. He treats samples which are taken from the sand traps of the wastewater treatment plants and consist of exactly that mixture. The sediments of household and industry waste water not only contain sand, clay or leaves but anything that people nowadays dispose of through the sewer system: cellulose, hair and especially food residues.
  • Quality control of cement

    Quality control is an important aspect of cement production. Sample preparation is an essential part of it, because only a representative and reproducible processing of the sample material ensures reliable and meaningful analysis results. RETSCH offers a range of instruments for dividing, crushing, grinding and sizing all materials which are involved in the production process of cement, including secondary fuels. To ensure the right choice of instrument for the right sample material, Retsch offers free-of-charge sample testing in application laboratories all over the world.
    Elemental analysers based on combustion technology are a useful addition to XRF analysis for the quality control of cement and related products, ensuring fast, precise and reliable determination of carbon and sulphur. With its offering of analyzers using resistance or induction furnaces or both, ELTRA covers a wide range of applications for C and S determination in organic and inorganic samples. The product range is ideally suited to the variety of analytical applications in a cement plant.
  • Quality control of coal: The influence of sample preparation on elemental analysis results

    The most common types of coal (lignite, bituminous and anthracite) are distinguished by their different chemical and physical properties. The calorific value of coal can be determined by analyzing its carbon content, for example with combustion analyzers. In addition, efficient management of the desulfurization plant requires control of the sulfur content. Compared to the large amount of coal a typical laboratory sample consists of - a 10 liter bucket or even more - the sample volume required for analysis is fairly low, only approx. 1 g. The standard DIN 51701 defines the sample amount to be tested as this relates to the particle size: The bigger the particles are, the more sample material is required.
  • Quick and reproducible grinding of feedstuff

    Grain, compound feeds or feed pellets occur in a variety of forms; compound feeds are usually inhomogeneous. Feedstuff is analyzed, for example, to determine the nutritional value, to detect hazardous substances or genetically modified ingredients. To ensure meaningful and reliable analysis results, representative and homogeneous samples are required. Therefore, sample preparation involves homogenization and size reduction of the material to a defined particle size. RETSCH laboratory mills are perfectly suited for this process.
  • Renewable energies on the rise

    Sample preparation of vegetable-based raw materials with laboratory mills

    Thanks to the increasing usage of biomass as a source of energy, the analysis of these materials in the context of R&D and quality control gains importance, too. Due to the complex properties of plant materials, adequate sample preparation can be rather a challenge.
  • Representative Sample Preparation to Environmental Analysis

    The prevention of environmental pollution is a prime issue of today’s industrialized societies. Important instruments in this context are regular checks using the latest analytical methods. Beside air and water analysis the focus is also on environmental remediation and declaration analyses as well as examination of soils, construction waste, sediments, secondary fuels and many more. Prevention and ecological recycling and disposal are the key words of a modern environmental policy. If the production of waste cannot be prevented, the primary objective is its material or energetic recycling. Residuals which cannot be recycled have to be disposed of in an ecologically friendly way.
  • Representative sample preparation for XRF analysis

    Preparing homogeneous samples by milling
  • Sample Preparation and Analysis of Arsenic in Rice

    Considerable care must be taken when analyzing a sample like rice in order to achieve an accurate result. The major source of error when analyzing a bulk material comes not from the analytical measurement itself, but from the sample handling, i.e., sampling, sample division, grinding, digestion, etc.
  • Sample Preparation for HPLC Analysis of Confectionery

    Like all foodstuff, confectionery is subjected to strict quality controls. Parameters of interest are, for example, nutritional value, moisture or fat content, or the quantification of particular ingredients, such as vitamins or alkaloids. Typically, chromatographic methods like High Performance Liquid Chromatography (HPLC) are used to analyze food samples. Most analytical methods only require a few milligram or gram of sample; the previous size reduction/homogenization process ensures that the small analysis sample is representative of the entire laboratory sample, thus allowing for reproducible results. Moreover, homogenized samples show a much better extraction behavior.
  • Sample Preparation in the Pharmaceutical Industry

    In the analysis of solid material, the popular adage that “bigger is better” certainly does not apply. The goal is to produce particles that are sufficiently small to satisfy the requirements of the analysis while ensuring that the final sample accurately represents the original material. The “particles” of interest to the analyst generally range from 10 µm to 2mm. Additionally there are many application, where even finer sizes are needed. One example are active ingredients, where it is necessary to grind in the submicron range. Finally for DNA or RNA extraction mechanical cell lysis is well-established. Materials differ widely in their composition and physical properties. Hence, there are many different grinding principles that can be applied, and this, together with other variables such as initial feed or “lump” size, fineness needed and amount of sample available, results in a wide range of models available to the researcher.
  • 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.
  • 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.
  • Sample preparation of PET preforms for subsequent analytics

    In the beverage industry plastic bottles – or rather their performs - are analyzed for their acetaldehyde content to prevent any health risk for consumers. The acetaldehyde must be extracted from the preforms prior to analysis. To ensure correct results, the bottles first have to be crushed and homogenized by laboratory mills. Care must be taken that the volatile substance acetaldehyde does not escape during the process due to heat build-up inside the grinding chamber. To preserve the acetaldehyde, part of the sample preparation is carried out under cryogenic conditions.
  • Sample preparation of electronic scrap with SM 2000 and ZM 200

    RETSCH mills in the context of RoHS and WEEE
  • Sample preparation of feeds and forage for NIR analysis

    The feed quality has a decisive influence on the productivity of livestock farming. However,  high-quality forage considerably adds to the costs of stock breeding. Consequently, economic considerations focus on the quality and quantity of the components used in the production process. This includes reliable analyses of feedstuff and ingredients from receipt of goods to final inspection as the best way to ensure a balanced feeding of the animals while keeping cost and profit orientation in focus.
    Near Infrared Spectroscopy (NIR) is the most important analytical method for the determination of protein content, moisture, fat and ash in feeds and forage. The advantage over classical methods such as Kjeldahl is the simultaneous determination
    of several parameters. Moreover, NIR spectroscopy is a quick method, which requires neither consumables nor reagents.
  • Sample preparation of feeds and forage for NIR analysis

    Als Standard Analysenmethode für den Gehalt an Protein, Fett, Kohlenhydrat und Feuchte kommt in der Futtermittelindustrie vor allem die Nah-Infrarot (NIR) Spektroskopie zum Einsatz. Der labortechnische Aufwand für die Probenvorbereitung und  Messung mit dem NIR-Verfahren ist vergleichsweise gering. Entsprechend weit verbreitet ist das Prüfverfahren. Die empfindliche spektroskopische Technik setzt voraus, dass die zu analysierende Probe repräsentativ ist, eine ausreichende Analysenfeinheit besitzt und eine möglichst hohe Homogenität aufweist. Hierdurch werden Messartefakte verhindert bzw. auf ein Minimum reduziert.
  • 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.
  • Sick with Dolls

    Traces of Heavy Metals in Toys
  • Size reduction of elastic plastics with volatile components

    Neutral-to-analysis sample preparation for the detection of PAH and phthalates
  • The effect of grinding tools on metal contamination

    Reliable and accurate analysis results can only be guaranteed by reproducible sample preparation. This consists of transforming a laboratory sample into a representative part sample with homogeneous analytical fineness. Retsch offers a comprehensive range of the most modern mills and crushers for coarse, fine and ultra-fine size reduction of almost any material. The product range also comprises a wide choice of grinding tools and accessories which helps to ensure contamination-free preparation of a great variety of sample materials.
    The selection of the correct grinding tool depends on the sample material and the subsequent method of analysis. Different grinding tools have different characteristics, such as required energy input, hardness or wear-resistance.
  • Time Advantage in Pharmaceutical Research: Sample Preparation with the High Energy Ball Mill Emax

    The development of drugs with poorly soluble to insoluble active ingredients is a big challenge for the pharmaceutical industry. The bioavailability of orally taken active ingredients, which means to what extent and in which period of time the substance is ingested by the body and is available at the place of action, strongly depends on the percentage dissolved in the gastrointestinal tract. One way to improve the solubility and thus the bioavailability of active ingredients is the pulverization of these substances. By minimizing the particle size to the micron and submicron range the surface-volume-ratio is increased and the solubility of the particles is improved. The pulverized particles are suitable for use in a variety of dosage forms, for example classic tablets or capsules.
  • 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.
  • Tracing poison - Sample preparation for analysis of toxic elements

    Reports on findings of hazardous substances in food products are nothing unusual these days: pesticides in fruit, arsenic in rice or toxic plant parts in tea, to name but a few. Therefore, permanent quality control is an indispensable tool of consumer protection. Apart from the actual food testing, sample preparation by homogenization is essential to obtain reliable results.
  • Tracking Down Fake Cashmere

    Cashmere wool is the best known precious wool. It is won from the cashmere goat which originates from the high mountain region of the same name. Due to its properties such as softness and warmth, cashmere wool gains more and more popularity in the manufacture of clothing. Genuine cashmere is won solely from the goat’s downy hair and must possess a certain hair structure with an exactly defined length and thickness.
  • What's in the fish - Effective size reduction by cutting

    The homogenization of fish is a challenge; scales, skin and bones are fairly resistant to size reduction so that the sample still contains some larger pieces after grinding in most mills. A high fat content of the fish makes the process even more difficult, as fatty particles stick together to form large lumps which block the mill and keep the sample inhomogeneous.
  • What Hair Reveals

    The detection of illegal drugs and pharmaceuticals plays a role in various fields, for example in forensic science, road traffic accidents, in competitive sports or at the workplace. Chemical substances can be detected in blood, saliva, urine and in hair. Hair has the great advantage of storing the substances for a long period, which means that detection is still possible several months after consumption of the drug. In addition to the detection of drugs, hair samples are also used for DNA analysis as well as for the analysis of heavy metals and minerals.
  • White Paper: Cryogenic Preparation of Sample Materials

    A solid sample material should always be sufficiently prepared by size reduction and homogenization before it is subjected to chemical or physical analysis. Care should be taken that the analysis sample fully represents the original material and that the sample preparation process is carried out reproducibly. Only then are meaningful results guaranteed. Most sample materials can be reduced to the required analytical fineness at room temperature by choosing a mill with a suitable size reduction principle (impact, pressure, friction, shearing, cutting).
  • White Paper: How to minimize standard deviations by correct sample preparation

    Modern analytical methods increase precision and push detection limits to make even the smallest traces of sample components detectable. Despite this development sample preparation, which is carried out prior to the actual analysis, is frequently neglected. Errors caused by lacking accuracy in sample preparation have a much bigger impact than errors made during analysis. Just like an iceberg which is mostly hidden under water, only a small part of the sum of errors is perceived whereas the major part of potential errors is not taken into account (fig. 1). One of the reasons may be the fact that sampling and sample preparation have always been done in a traditional way which has become a routine over the years and is no longer considered as having a critical influence on the subsequent analyses.
  • White Paper: Rapid and efficient disruption of yeast cells with the Mixer Mill MM 400

    Cell disruption of bacteria, yeast, filamentous fungi or microalgae is a standard procedure in basic biological research, applied biotechnology or medical research to get access to nucleic acids (DNA, RNA) or cell proteins. For the isolation of DNA or RNA usually less than 1 ml of cell material is needed. For the extraction of proteins, however, larger amounts of cell suspension are required. A very efficient method of cell disruption is the co called “bead beating” where cells in suspension are mechanically disrupted by glass beads in single-use reaction vials.
  • White Paper: 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.
  • White Paper: 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.
  • White gold - Grinding large sample volumes

    Rock salt and sea salt not only consist of sodium chloride but may also contain other minerals and silicates, depending on the mining area and method. To analyze the composition of salt, the sample needs to be sufficiently homogenized, considering that larger lumps of rock salt are usually very inhomogeneous. The element concentrations in salt are usually very low so that it is frequently necessary to process amounts in the kilogram range. The Rotor Beater Mill SR 300 easily pulverizes charges of several kilogram and is therefore ideally suited for this application.