issue 37 | information from the field of solids preparation and

NEW

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Issue 37 | Information from the field of solids preparation and characterization in laboratories and processing industries

the

sam

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in sample preparation and particle analysisnew Dimensions

Available at MEP instrumentsAustralia - New Zealand

MEPinstrumentsThe right chemistry.

M706 sample37_englischCS5.5.indd 1 11/08/2012 15:42

| the sample 37 | www.retsch.com2

A faultless and comparable analysis is closely linked to accurate sample handling. Only a sample representative of the initial material can provide meaningful analysis results. This can be achieved by using RETSCH’s new laboratory sample divider PT 100. It divides the sample so exactly that the composition of each of the 6, 8 or 10 fractions corresponds exactly to that of the original bulk sample. The new rotating tube divider PT 200 allows for the represen-tative, dust-free extraction of up to three partial samples from larger volumes of bulk goods. The ratio of the fractions is freely adjustable. Both dividers feature digital time setting and comfortable quick-release clamps.

Benefits PT series:■ Extremely high division accuracy

■ Digital timer

■ Modular design

■ Automatic material feed via synchronized feeder

■ Quick-release clamping system for simple and rapid handling of sample vessels

www.retsch.com/pt100www.retsch.com/pt200

PRODUCT NEWS 2012Sample DividersPT 100 & PT 200

Dear Readers, Customers, and Business Partners,

In this issue of “the sample”, we would like to invite you to enter a new dimension in sample prep-aration and particle analysis with us. RETSCH has launched a new campaign, “The Future is Now”, which will give you the chance to win a Zero G flight if you take part in the competition on www.retsch.com/future!

Many of you are familiar with the high quality and reliability of our instruments. In this issue, select-ed users of RETSCH devices tell us about their application which, in some cases, is rather unusual and shows how versatile our mills and sieve shakers are. Maybe you also have an interesting applica-tion with RETSCH instruments? Then we would be glad to hear about it.

Of course we also present new products in the year of Analytica and Achema. Beside the re-design of our sample dividers and the vibratory feeder DR 100, we have added another sieve shaker for dry sieving of large volumes to our product line. This further strengthens our position as a manufacturer of particle analysis systems with the widest range of measuring principles. In view of Achema I can promise you more new products to come. We would be happy to welcome you at one of the trade shows so you can see for yourself.

We hope you enjoy reading this issue of “the sample”!

Yours

Dr. Jürgen PankratzManaging Director

EDITORIAL

NEW


www.retsch.com | the sample 37 | 3

The vibratory feeder DR 100 is used for the uniform, continuous feeding and conveyance of pourable bulk materials and fine powders. The DR 100 feeds RETSCH mills, sample dividers, and particle measuring systems. The DR 100 can be driven and controlled externally via the built-in interface. RETSCH vibratory feeders guaran-tee reproducibly exact results and maximize the effi-ciency of downstream laboratory and testing devices.

Benefits DR 100■ Strong drive for even material feed

■ Material bed level and volume flow are adjustable

■ Optional control via interface

■ Digital setting of time and speed

■ Wide range of accessories including various chutes

www.retsch.com/dr100

With the AS 450 basic, RETSCH introduces a budget-priced alternative to the AS 450 control sieve shaker. The new sieve shaker covers a size range from 25 μm to 125 mm and accepts loads of up to 15 kg. Time and amplitude are digitally set to ensure repro-ducible sieving. The AS 450 basic is suitable for dry sieving. It is the economic solution for customers who need to sieve larger quantities with reliable results.

Benefits AS 450 basic:■ Efficient electromagnetic drive with 3D

movement

■ Easy operation, ergonomic design

■ Excellent separation efficiency even with short sieving times

■ Up to 11 fractions in one sieving operation

■ Digital setting of time and amplitude

www.retsch.com/as450basic

Vibratory Sieve Shaker AS 450 basic

Vibratory Feeder DR 100

Jaw Crusher BB 50Complete re-design of the compact benchtop model for coarse and preliminary size reduction with new features!

COMINGSOON!

NEW

NEW



Knife MillsGRINDOMIX GM 200/GM 300www.retsch.com/gm200www.retsch.com/gm300

Mixer Mill MM 400www.retsch.com/mm400


The Italian contract laboratory pH s.r.l. is equipped with a variety of sample preparation and analysis tools including some RETSCH mills, such as four Knife Mills GRINDOMIX GM 200, one GRINDOMIX GM 300 and one high-speed Ultra Centrifugal Mill ZM 200.

pH Lab is involved in food and feed analysis for many of the major Italian food producers. The neutral-to-analysis preparation of food samples is of crucial impor-tance, especially for the detection of mycotoxins and pesticides. For this type of analysis it is manda-tory to obtain a fully homogenized sample and to avoid sample heating to preserve the volatile components.

pH Lab tries to keep the sample preparation process as efficient as possible. With an average workload of 15 to 20 samples per day, time saving is an important issue. They frequently process vegetable and fruit samples. For smaller volumes, they use the Knife Mill GRINDOMIX GM 200 but if larger quantities need to be homogenized, the bigger GM 300 provides the best results as it allows for processing of up to 4,500 ml sample material.

With the GM 300 they are able, for example, to process up to 8 bananas in one shot, without pre-cutting the sample. By using the patented gravity lid, which dynamically reduces the volume of the grinding cham-ber, they are able to obtain a perfectly homogenized result. After the sample preparation they add the QuEChERS reactive solution in order to examine the pesticides contamination. Depending on the sample properties, they sometimes mix it with dry ice (ratio 2:1) to improve the breaking behavior, using the stain-less steel container.

Mr. Manuele Mecacci of pH Lab is convinced of the benefits of the GM 300: “We are fully satisfied with the performance of the new RETSCH GM 300 equipped with the gravity lid! To obtain such a high degree of homog-enization was impossible with the equipment we used before. Moreover, the GM 300 helps us to save time as it processes most samples within seconds.”

T E S T I M O N I A L

Preparing foodstuff in a contract laboratory

Sample preparation for pesticide residue analysis with the QuEChERS method


Manuele Mecacci with the GRINDOMIX GM 300.

The new adapter for the MM 400 allows to use up to 8 Falcon tubes (50 mL)


The company pH S.r.l., located near Florence, is a leading Italian contract laboratory founded in 1982. It specializes in areas such as alimentary auto-regulation, safety on work sites, industrial hygiene, environment, quality and training, representing, among other things, a valid support for product certification and produc-tion line traceability.

pH s.r.l., Italy

www.phsrl.it

PERFORMANCE DATA

Knife Mill GRINDOMIX GM 300Applications: size reduction, homogenization and mixing Feed material: soft, medium-hard, elastic, containing water / fat / oil, dry, fibrous Material feed size*: ~ 130 mmFinal fineness*: < 300 µm

MIXER MILL MM 400Applications: size reduction, mixing, homogenization, cell disruption, cryogenic grindingFeed material: hard, medium-hard, soft, brittle, elastic, fibrousMaterial feed size*: ≤8mmFinal fineness*: ~ 5 µm

*depending on feed material and instrument configuration/settings

NEW

“To obtain such a high degree of homogeni-

zation was impossible before we used the

GM 300.”

Manuele Mecacci, pH s.r.l.Sample preparation for pesticide residue analysis with the QuEChERS method

T he so-called QuEChERS method (“quick, easy, cheap, effective, rugged and safe”) was devel-

oped by Michelangelo Anastassiades (Chemical and Veterinary Investigation Office CVUA, Stuttgart, Germany) to make sample preparation to pesticide residue analysis more efficient. It basically consists of three steps: Homogenization – Extraction – Anal-ysis. Test series have proved that the analysis results obtained with the QuEChERS method can easily com-pare with more common methods, such as DFG S19.

During the homogenization process, care must be taken that the sample does not get too warm as some pesticides are volatile. Therefore it is recommendable to cool the sample which also improves the breaking behavior of the material thus achieving a higher fine-ness and homogeneity. For this purpose, a special lid was developed for the GM 300 to be used when grinding samples mixed with dry ice. An alternative option is the RETSCH CryoMill which continually cools the sample with liquid nitrogen.

After the homogenization, 10 g of the food sample are extracted with 10 ml acetonitrile. As the next step the organic phase is dried and tested for pesticides with chromatographic analysis. To avoid ghost peaks in the chromatograms, the sample is extracted in the pres-ence of a salt mixture (e.g. sodium chloride and mag-nesium sulphate in a 1:2 ratio). This mixture can be easily obtained by using a professional sample divider like RETSCH’s PT 100. With this rotating divider the salts are reproducibly mixed so that the composition of each fraction is identical. In this way, up to 10 salt mixtures can be obtained in reproducible quality.

To transfer the pesticides from the sample into the organic phase, the mixture is agitated for 1 to 3 min-utes with the acetonitrile and salt. The mixture can be agitated by a laboratory mill such as RETSCH’s Mixer Mill MM 400. It moves the sample in a 50 mL Falcon tube with a frequency of up to 30 Hz thus ensuring thorough mixing of the sample which is beneficial for the subsequent extraction.




Vibratory Sieve Shaker AS 450 controlwww.retsch.com/as450control

Jaw Crusher BB 50www.retsch.com/bb51

Rotating Tube Divider PT 200www.retsch.com/pt200

Sample DividerPT 100www.retsch.com/pt100

Recycled glass – a valuable resource

Today, recycled glass is the most important resource for the glass industry. The processed glass can be

reintroduced to the melting process any number of times and made into new products. In Germany, currently up to 95 % of recycled glass is used for producing glass, which has various advantages: energy saving, less con-sumption of primary raw materials (such as lime and silica sand) and the reduction of landfill costs for waste glass.

The glass which the consumer dumps in the waste container is collected and processed in modern recycling plants. The waste glass passes several stations such as opto-physical sorting machines and magnetic or eddy current separators which handle materials such as porcelain, ceramics, stones, metal, paper, plastics, off-colors, glass ceramic and lead glass, ensur-ing that the recycled glass is largely free of impurities and can be reintroduced to the production circle of the glass kilns.

Quality control of the recycled glass is of great importance as the remaining impurities in the glass may cause problems dur-ing or after the melting process. Extraneous materials such as stones or metal produce melting residues, so-called enclaves, in the glass which reduce the stability of the glass, and cause it to break more easily. Whereas most routine inspections in glass kilns or recycling plants are carried out without pre-treatment of the sample and with a mere visual control of the impurities, the German Institute of Glass and Resource Tech-nology (IGR) always classifies the material with a RETSCH AS 450 control sieve shaker. Thus it is possible to detect considerably larger concentrations of impurities which almost match the actual percentage in the processed recycled glass.

| the sample 37 | www.retsch.com

NEW

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To evaluate the quality and application areas of the broken glass fragments, analysis of the chemical composition is crucial. Beside glass-specific ele-ments such as silicium, natrium, cal-cium, magnesium and potassium, there are also heavy metals to be found such as lead, cadmium, mercury, arsenic and chromophoric elements such as iron, chrome, cobalt etc.. Usually, only very small sample volumes are used for routine analyses in the glass kilns and recycling plants, and the sample is not homogenized prior to examina-tion. As a result, the analyzed element concentrations vary strongly. Moreover, some of the heavy metals and chro-mophoric elements are not detected at all in routine analyses.

A guide value for chemically processed recycled glass is, for example, a content of≤350ppmPbO.However,ifbychancea single lead glass fragment (24 % PbO) with a weight of 6 g is contained in the total sample volume of 10 kg, the PbO concentration increases by 100 ppm. Consequently, analyzing this sample would result in a PbO content of 380 ppm instead of the original average concentration of, e.g., 280 ppm.

The most reliable method to obtain representative samples for chem-

ical analyses is to reduce the sam-ple in size, if required in two steps, and to divide it. To ensure the required statistical certainty and accu-racy of the analysis results, a homo-geneous sample volume of approx. 300 kg to 800 kg waste glass is required, depending on the element concentrations to be detected and the masses to be examined (for example a truck with a 25 t load or a batch with 3,000 t). The IGR divides the entire homogeneous sample quantity of a few 100 kg, crushes it in turn with the RETSCH Jaw Crusher BB 200 (jaws and wearing plates of tungsten carbide) and the Jaw Crusher BB 51 (jaws and wearing plates of zirconium oxide) and finally divides it representatively with RETSCH’s Sample Divider PT 100. In a next step a homogeneous part sample of 40 g is ground either with the Planetary Ball Mill PM 100 (agate grinding jar and balls) or with the Mixer Mill MM 400 (zirconium oxide grinding jars and balls). Thanks to the variety of materials of the grinding tools offered by RETSCH, contamina-tion-free grinding is ensured.

From this sample 0.3 g are taken, various acids are added and the sam-ple is then thermally treated in special crucible, open or closed, and digested.

After that the now water-soluble sam-ple is acidified and filled into a volu-metric flask. The sample of recycled glass is finally analyzed with an ICP-OES spectrometer for the concentra-tions of more than 30 elements.

Thanks to the preparation and analysis procedure developed and applied by the IGR, the rather small sample weight of 0.3 g represents with high statistical certainty the original sample volume of 25 t or 3,000 t respectively. This was successfully proved by vari-ous round robin tests and reference analyses.

IGR – Institute for Glass and Resource Technology The Institute for Glass and Resource Technology situ-ated in Goettingen, Germany, is an independent service company whose core competence is focused on all sub-jects related to glass. The IGR is also involved in areas such as ceramics, refractories, construction materials and metals, as well as waste. Due to many years of experience in the fields of glass production and glass analysis the IGR has not only acquired profound expert knowledge but has also set up a proven system of qual-ity control measures which comply with the requirements of the DIN EN ISO/IEC 17025.

www.igrgmbh.de

PERFORMANCE DATA

JAW CRUSHER BB 51Applications: Coarse and pre-crushingFeed material: medium-hard, hard, brittle, toughMaterial feed size*: < 35 mm Final fineness*: < 0.5 mm

SAMPLE DIVIDER PT 100Applications: Sample division and reductionFeed material: Bulk materialsMaterial feed size*: ≤10mmFeedcapacity* ≤5,000mlNumber of divisions: 6, 8 or 10


Managing Director Dirk Diederich and his colleagues



| the sample 37 | www.retsch.com8 | the sample 37 | www.retsch.com8

The Michael Rout Lab at the Rockefeller University in New York, NY, initially contacted RETSCH Inc. in 2006 to

discuss the possibility of using the Planetary Ball Mill to cryo-genically grind yeast cell pellets. The aim of their experiment was to explore the construct of Nuclear Pore Complexes located on the cell walls of yeast cells. The decision to use a Planetary Ball Mill for this application was mainly based on the fact that it produces very small particle sizes which were considered an important pre-requisite for more in-depth analysis of the yeast cells. Particle sizes in the submicron range promote a high yield for the follow-ing protein purification.

Since the Planetary Ball Mills are not specially designed for cryogenic grinding, the Rout Lab worked out a very specific protocol to achieve high yields (~90 %) of lysed yeast cells. The Rout Lab Protocol, “Cryogenic Disruption of Yeast Cells (RETSCH PM 100)”, which was developed in March of 2007, is available from their website. In addition to this pro-tocol, the lab members made a video as well to provide a visual walk through of the process (www.retsch.com/rout-protocol).

To date, the Rout Lab continues to utilize the Planetary Ball Mill for cryo-genically grinding yeast cells for continued research on the above men-tioned project as well as other universities research projects. RETSCH Inc. has currently 10 installations of the PM 100 Planetary Mill within US universities as a result of the Rout Lab collaboration.

The Rockefeller University was founded in 1901 by John D. Rock-efeller Sr. as The Rockefeller In-stitute for Medical Research. The first institution in the United States devoted solely to using biomedical research to understand the un-derlying causes of disease, Rock-efeller is today one of the foremost biomedical research centers in the world, and its scientists have made numerous seminal contribu-tions to biology and medicine.

Cryogenic Disruption of Yeast Cells


according to the Rout Protocol

PERFORMANCE DATA

PM 100Applications: pulverizing, mixing, homogenizing, colloidal milling, mechanical alloying Feed material: soft, hard, brittle, fibrous - dry or wet Material feed size*: < 10 mmFinal fineness*: < 1 µm, for colloidal grinding < 0.1 µmPlanetary Ball Mill

PM 100www.retsch.com/pm100

www.rockefeller.edu

Rockefeller University


“With more than 90 % of lysed cells,

this method with the PM 100 is more

efficient compared to lysis protocols

performed in a liquid environment.”

Dr. Célia Plisson-Chastang, LBME


Genetic Research in France

Not only in the US is the Planetary Ball Mill used for the cryogenic disruption of yeast cells. The University of Tou-louse, Fance, hosts the Laboratory of Eukaryotic Molecular Biology (LBME) which follows the Rout Proto-col for this application as well and has so far obtained very good results.

The research at LBME focuses on the genetic control of eukaryotic gene expression in normal and pathological contexts. These are fundamental research projects: the objective is to understand the molecular basis under-lying pathologies such as, for example, breast cancer. Their research relies on several model systems that range from unicellular to whole organisms, from yeast to mammals including primary and transformed cell lines.

Dr. Célia Plisson-Chastang of LBME operates the PM 100 with a 125 mL grinding jar of stainless steel and 7 to 11 grinding balls with 20 mm diameter of the same material to disrupt the yeast noodles. The next step is the chromato-graphic purification of the protein par-ticles and after that functional and structural analyses using electron microscopy and image analysis. With the PM 100 approximately 90 % of the yeast cells are disrupted.

Dr. Célia Plisson-Chastang appreciates the benefits of this method: “RETSCH’s PM 100 allows to process up to 25 g pf frozen yeast noodles in one working of run. With more than 90 % of lysed cells, this method is more efficient compared to lysis protocols performed in a liquid environment. Cells and cell grindates are manipulated at very low tempera-tures (ranging from -80 °C during stor-age to -196 °C when cooled in liquid nitrogen) all the time, thus preventing our ribonucleoproteic particles of inter-est to be damaged by released enzymes, such as proteases and nucle-ases.”

The RETSCH CryoMill is also highly suitable for cryogenic cell disruption.


1.) Always wear cryo-gloves.

2.) Fill a rectangular ice bucket about ¼ full with liquid nitrogen.

3.) Pre-chill everything. Immerse the stainless steel grinding jars, the stainless steel lid, the grinding balls and the storage tube, with the frozen yeast noodles, in the liquid nitrogen.

4.) Pre-cooling is finished when nitrogen bath is no longer bubbling vigorously.

5.) Once everything is chilled pour the noodles into the grinding jar.

- 20 mL - 50 mL of noodles: 125 mL jar - 20 mL and less of noodles: 50 mL jar

6.) Weigh the grinding jar with noodles and then adjust the counterbalance weight.

7.) When using the 125 mL jar, use 7-11 of the 20 mm stainless steel balls.

- 50 mL Falcon tube requires 7-9 balls - < 50 mL of noodles requires 9-11 balls - < 25 mL of noodles requires 11 balls - < 15 mL of noodles use 50 mL grinding jar requires 3 balls

8.) Be sure no liquid nitrogen is in the grinding jar prior to grinding to avoid an explosion.

9.) Grinding is done in 8 cycles, each cycle is set in the following manner:

- 400 RPM - 3 minutes - 1 minute reverse rotation with

no breaks between rotations (NOTE: You MUST hear the balls

rattling around in the jar! If there is no rattling then add/remove balls to the jar until you hear it rattle. It is not considered a grinding cycle unless there is rattling.)

When using the 50 mL jar the grinding settings are as follows:

- 500 RPM - 3 minutes - 1 minute reverse rotation with

no breaks between rotations (NOTE: You MUST hear the balls

rattling around in the jar! If there is no rattling then add/remove balls to the jar until you hear it rattle. It is not considered a grinding cycle unless there is rattling.)

10.) Between each cycle the jars are removed and cooled in liquid nitrogen. DO NOT REMOVE THE LID (removal of lid may result in cell loss)! To ensure lid is chilled use an empty Falcon tube to pour liquid nitrogen over the top of the grinding jar while the bowl of the grinding jar cools in the liquid nitrogen bath. DO NOT SUBMERGE THE JAR COMPLETELY as this will allow liquid nitrogen into the grinding bowl and may also result in cell loss.

11.) When 8 cycles are complete remove powder with a spatula – if there is powder stuck to the side of the jar repeat 1 grinding cycle at 350 RPM, 2 minutes, 1 minute reverse rotation no breaks between rotations.

12.) Jars and balls can be cleaned with warm water and Windex.

13.) Typically ~90 % of yeast cells can be disrupted in such procedure. Frozen ground cells are stored at -80 °C.

Dr. Célia Plisson-Chastang with the PM 100

THE ROUT PROTOCOL

Cryogenic Disruption of Yeast Lysing of frozen yeast cells using a RETSCH PM 100 Planetary Ball Mill.


AVAILABLE AT:



Scrap turned into raw materials

The EU directive 2000/53/EG stipulates that as of 2015 95 % of the weight of a car that has reached

the end of its life span have to be recycled. The work of ARN is strongly focused on this objective. Together with partner companies they make sure that old cars are pro-cessed in an environmentally compliant way. The recycling chain begins with the companies that dismantle the car and remove raw materials and liquids. Waste manage-ment companies collect these materials and deliver them to the processing companies who reuse the materials in accordance with high production standards.

ARN Car Recycling Netherlands

ARN (Auto Recycling Nederland) was founded by the automobile industry in 1995 following the passing of an EU directive which stipulates that cars have to be sustainably exploited at the end of their life span. ARN see them-selves as an advisory body with-in a network of 300 partner companies who guarantee a very effective process from the dis-mantling of the car and the dis-posal of waste to the actual recycling.

www.arn.nl

Cutting Mill SM 300 with cyclone-suction combinationwww.retsch.com/sm300


Ultra Centrifugal Mill ZM 200www.retsch.com/zm200




In April 2011, ARN opened a production site at Tiel which forms the last chain link in the transformation process of shredded waste to reusable raw materials.

After a car wreck has been emptied and dismantled, the remaining parts are put into a shredder. The resulting shredded light scrap (without metals) is then separated into 3 fractions: raw sand, raw fluff and raw granulate. These fractions are delivered to ARN where they are processed and refined in highly modern production facilities.

Marcel van der Veer, Manager Quality and Environment, explains: “Our pro-duction facilities are designed for 100,000 tons per year. We are planning on processing all of the Dutch shredder light scrap which amounts to 35,000 tons. The recycling of car scrap will of course remain our main task but it is also conceivable that we will in future process electronic scrap and plastic waste as well in order to produce with maximum capacity.”

To ensure reliable inbound and out-bound inspection, the laboratory at Tiel is very well equipped. Their customers are critical and very demanding when it comes to the quality of the recycled raw materials supplied by ARN: “We deliver, for example, materials for the dewatering of sludge in wastewater treatment plants. Or heating material for furnaces where the operator needs to know in detail what kind of material is burnt”, explains lab coordinator Anita van Ooijen.

For these reasons, constant quality control is a big issue at Auto Recycling Nederland. Typical analyses include, for example, the determination of ash content, dry matter content, calorific value as well as the PCB and PAC con-tent. Moreover, the percentage of min-erals, oils or heavy metals is deter-mined as well as the nitrogen, carbon or sulfur content.

The variety of materials which ARN produces is great. Therefore, the lab has acquired several different RETSCH instruments to prepare the required analytical samples. Anita van Ooijen appreciates the good quality of the

RETSCH equipment: “We use RETSCH mills and sievers because we know they work well and are easy to operate and clean. Working with RETSCH equipment is a piece of cake!”

For the grinding of fibers and plastics, which are pre-chilled in liquid nitrogen, the laboratory uses a RETSCH Cutting Mill SM 300. Anita van Ooijen: “The SM 300 is perfectly suited for grinding plastics!”

RETSCH’s Ultra Centrifugal Mill ZM 200 is used to grind small pieces of rubber which are also pre-cooled with LN2, whereas the RETSCH Plan-etary Ball Mill PM 100 predominant-ly grinds the hard-brittle components of the shredded waste. Anita van Ooi-jen comments that “the PM 100 pro-vides excellent grinding results; we merely use a bit of methanol to prevent the sample from caking to the jar walls.”

Particle size analysis is also an issue at ARN laboratory in Tiel as the particle size distribution of a product, among other factors, influences further pro-cessing and use. For this application, the lab uses RETSCH’s Vibratory Sieve Shaker AS 450 control which separates up to 25 kg of sample mate-rial very efficiently, even with short sieving times.

Working with the ZM 200

Planetary Ball Mill PM 100www.retsch.com/pm100

Vibratory Sieve Shaker AS 450 controlwww.retsch.com//as450control

“Working with RETSCH

equipment is a piece

of cake!”

Anita van Ooijen, ARN

End-of-life vehicles re-used


AVAILABLE AT:





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 char-acterize the particle size of bulk goods.

In a running production process, the results of a quality check must be available quickly to allow for immediate adjustment of the pro-duction 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. The classic methods of sieving bulk goods with vibratory, horizontal or tap sieve shakers are limited to sizes above 40 microns. When using vibratory sieve shakers for wet sieving, it is possible to push the limit to 20 microns. However, this method involves dispersion of the sample in liquid, filtration after sieving, drying and finally weighing the obtained fractions. For dry sieving of samples with particle sizes below 40 microns, air jet sieving is the method of choice. It can also be a faster alternative to vibratory sieving for particle sizes up to 200 microns. All methods mentioned here are suitable for deter-mining the the undersize and oversize (so-called sieve cut) as well as the particle size distribution of a sample.

Vibratory Sieve ShakersAS 200/AS 300/AS 400/AS 450www.retsch.com/as

Tap Sieve ShakerAS 200 tapwww.retsch.com/as200tap

Air Jet Sieving MachineAS 200 jetwww.retsch.com/as200jet

Particle Size - A Quality Feature


AVAILABLE AT:


Test sieving of talc powder for chewing gum production

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.

“Regular sieving machines cannot separate fine powders such as talc”, explains Evgenia Slavina, a Quality Assurance Specialist in the testing laboratory. “Talc is used in chew-ing gum production to prevent adhesion of plates in the package (a so-called “rolling compound”). The fineness of the powder should not exceed 40 microns. The air jet sieving machine AS 200 jet helps us to control this parameter here in our laboratory. We were advised by our col-leagues from Chicago to use the RETSCH air jet

sieve and they were right. We use it with the powerful industrial vacuum cleaner GM80 which provides sufficient airflow to break the agglomerates. Thanks to adjustable nozzle speed and open mesh function the AS 200 jet is very flexible and makes the sieving process easy and totally reproducible.”

In confections manufacture the fineness of acids also plays an important role. It should not exceed 150 microns to provide the desired solubility of the product. Sieving of such powders in an air jet sieving machine is a faster and more reliable alternative to vibra-tory sieving.

RETSCH’s vibratory sieve shaker AS 200 control is also used in the laboratory for fractional analysis of sugar and different sweeteners. The reproducibility of the sieving process due to digital control of all parameters, as well as a wide range of high quality test sieves make handling of this instrument reliable and easy.


PERFORMANCE DATA

AIR JET SIEVING MACHINE AS 200 JETApplications: separation, fractioning, particle size determination Feed material: powders Measuring range*: 10 µm - ~ 4 mm Max. batch: 0.3 - 100 g Max. Number of fractions: 1 (by using a cyclone: 2)

VIBRATORY SIEVE SHAKER AS 200 CONTROLApplications: separation, fractioning, particle size determination Feed material: powders, bulk materials, suspensions Measuring range*: 20 µm - 25 mm Max. batch: 3 kg Max. number of fractions: 9 / 17


The Wm. Wrigley Jr. Company is a recognized leader in confections with a wide range of product of-ferings including gum, mints, hard and chewy candies, lollipops, and chocolate. The company has op-erations in more than 40 countries and distributes its brands in more than 180 countries. Wrigley is headquartered in Chicago, USA, and operates as a subsidiary of Mars, Incorporated, a private, family-owned company founded in 1911. Since 1992 the company operates in the Russian market. It owns a factory in Saint Peters-burg which was built in 1998.

Wm. Wrigley Jr.

www.wrigley.com

“We were advised by our colleagues

from Chicago to use the RETSCH air

jet sieve and they were right.”

Evgenia Slavina, Wm. Wrigley Jr.



Solder powder consists of fine, mostly spherical metal particles. While in the past typically lead/tin alloys were used, modern manufacturing processes use lead-free alloys. The ever decreasing size of the components and structures on the circuit boards require highest accuracy and narrow particle size distribution.

Fluidity and wetting are the most impor-tant characteristics of the solder powder, as well as melting temperature, and oxide

content. These properties depend on composition of the alloy, additives and impurities, but also on the particle size distribution and particle shape. Uniform round particles have, for example, a bet-ter fluidity and can therefore be printed faster and more easily on the circuit boards. Moreover, due to the smaller surface area, they contain less oxide than irregularly shaped particles.

The requirements for solder powders are

described, for example, in the Joint Indus-try Standard J-STD006. According to this standard, a solder powder can be called “round” when more than 90 % of the material has a width-to-length ratio of at least 2:3 (0.67).

Cookson Electronics / Alpha Advanced Materials use the CAMSIZER XT for particle character-ization at their four regional manu-facturing facilities. This instrument,

Quality control of solder powders with the CAMSIZER XT

Cookson Electronics / Alpha Advanced Materials

The US American company Alpha Advanced Materials, a division of Cookson Electronics, is the global leader in the development, manufacturing and sales of innovative materials used in electronic assembly processes. With a worldwide presence in 50 locations Alpha develops and manufactures a complete product line of highest quality soldering materials.

www.alpha.cooksonelectronics.com

solder pastes are used in the electronics industry for reflow-soldering of SMD (surface mounted devices) components on printed circuit board (PCB) assemblies. The solder

paste is printed on the contact pads and the components are mounted on these pads. The paste attaches the components on the PCB until the PCB is heated in an oven where the solder paste melts. The melt connects the electronic components (resistors, transistors, ICs, EPROMS, etc.) and the contact pads of the PCB providing the electric contact and mechanical fixture after cooling and solidification. An essential component of solder paste, beside the flux, is the solder powder.


Different production sites, identical product quality

The measuring range of the CAMSIZER XT covers the complete size range of solder powders

◄Measurement results of the 6 most typical solder powders. Displayed are the cumulative distribution (Q3, left y-axis) and the corresponding relative fre-quency (q3, right y-axis)

type 2type 3type 4type 5type 6type 7

Q3 [%] q3 [%/µm]

10 20 30 40 50 60 x [µm]

90

80

70

60

50

40

30

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Mesh Size Particle Size [µm] Product Type -200 +325 75-45 2 -325 +500 45-25 3 -400 +635 38-20 4 -500 25-15 5 -635 15-5 6 11-2 7

Overview of different solder powders

The trend to minimize electronic compo-nents also affects the production of solder powders. Smaller spaces between com-ponents and circuits call for finer solder powders.

The following types of powders are the most common:



Optical Particle AnalyzerCAMSIZER XTwww.retsch.com/camsizerxt

which operates with Dynamic Image Analysis, measures the particle size dis-tribution of all standard solder powders with utmost precision and high resolution. The CAMSIZER XT not only optimizes the quality control of the end products but also the monitoring and control of inter-mediate production steps.

For solder powders it is crucial to have a narrow particle size distribution, meaning that all particles should have about the same size. This is usually achieved in a two-step process: First, the liquid metal is dropped on a rotating disk, a so-called “atomizer”. This gener-ates fine, almost round solder beads. Depending on the desired type of pow-der and required grain size, different process parameters have to be chosen. This raw powder is then sieved to obtain the desired narrow size distribution.

Oversize and undersize are melted again to be re-used with the raw material.

To obtain the maximum yield, the atom-izer should already produce a narrow size distribution with a high percentage of powder in the desired size range, ensur-ing that the subsequent sieving only produces a small amount of rejects. As CAMSIZER XT delivers fast and accu-rate size results, it helps to rapidly optimize the settings of the atom-izer and minimize rejects.

The precise measurement even of small-est amounts of oversize and undersize allows for close monitoring of the sieving process during production. Wear or block-age of sieves can be detected at an early stage. This helps to maximize main-tenance intervals and, at the same time, maintain consistent product quality.

Dynamic Image Analysis offers various advantages for measuring solder pow-ders compared to other methods such as sieve analysis or laser diffraction:

■ Simultaneous measurement of particle size and particle shape (sphericity, aspect ratio)

■ Fast and reliable detection of smallest amounts of oversize and undersize

■ Reproducible and comparable measur-ing results at all production sites

■ Quick optimization of production para-meters thanks to short measuring times

■ Simple and safe operation, software in various languages

■ Robust, maintenance-free design allows for usage in the laboratory as well as in a production environment

“Our global customers demand consistent quality and performance from our prod-

ucts without any site-to-site process variances. The implementation of the

CAMSIZER XT systems at our four regional manufacturing facilities will allow us

to measure and adjust our powder intermediates produced to ensure that we are

able to achieve these global consistency requirements in our end products.”

Frank Wiesinger, Global Process Engineering Group – Powder Coordinator,

Cookson Electronics / Alpha Advanced Materials

◄Comparison of the sphe-ricity of the solder pow-ders

type 2type 3type 4type 5type 6type 7

Q3 [%]

0.4 0.5 0.6 0.7 0.8 0.9 SPHT

90

80

70

60

50

40

30

20

10

0

sphericity

per

cen

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e non-round round



AVAILABLE AT:



Available in Australia at:

MEP Instruments Pty LtdUnit 11, 56 Buffalo RdGladesville, NSW 2111

Phone +61 2 8899 5200Fax +61 2 8899 5299

E-Mail [email protected] www.mep.net.au

Germany:

Retsch GmbH Retsch-Allee 1-542781 Haan

Phone +49(0)2104/2333-100 Fax +49(0)2104/2333-199

E-Mail [email protected] www.retsch.com

Available in New Zealand at:

MEP Instruments Ltd2 B, Unit D, 5 Ceres Court Mairangi Bay, Auckland, 0630

Phone +64 9 912 1330Fax +64 9 912 6892

E-Mail [email protected] www.mep.net.nz

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Stocked in AustraliaOrder your sieves from MEP today – quote “The Sample” and receive the free MEP coffee mug with each order!*

The most commonly requested sieves are held on stock by MEP for your convenience.

Contact Gareth at [email protected] or (02) 8899 5200 now for stock listing and pricing.*subject to availability.



issue 37 | information from the field of solids preparation and

Documents