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Aplikace/Zaměření leták (2)

Cement
The Art of Milling (White Paper)

Zákaznický časopis „the sample“ (6)

No. 38
INTRODUCING VERDER SCIENTIFIC DIVISION

No. 36
Umění mletí - Moderní technologie mletí

No. 34
NOVÉ PRODUKTY'10

No. 33
SAMPLE PREPARATION IN PRACTICE & NEW RETSCH INSTRUMENTS

No. 29
New Product Generation 2007

No. 28
Think big but grind fine!

Technické zprávy (16)

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.

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.

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.

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.

As pure as possivle
Even if size reduction is carried out under ideal conditions, the mechanical stress which the sample material exerts on the surface of the grinding tool causes abrasion. However, it is possible to minimize this effect by selecting suitable mills and grinding tools. If the sample material needs to be ground to sizes below 100 microns, strong mechanical forces are required which increase abrasion.

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.

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.

Sample Preparation for XRF Analysis
From sample to pellet

Renewable raw materials are gaining ground
The representative sample preparation of plants requires experience

Representative sample preparation for XRF analysis
Preparing homogeneous samples by milling

Fast and Reproducible Sample Preparation with a Vibratory Disc Mill
The Vibratory Disc Mill RS 200 from Retsch is used for the quick, loss-free grinding of hard, brittle and fibrous materials to analytical fineness.

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....

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.

The preparation of samples of solid substances for spectroscopic analysis
X-ray fluorescence spectrometry is one of the most versatile multi-element methods of chemical analysis. The technique is based on excitation of fluorescent radiation from a sample by bombarding it with high energy X-ray quanta and subsequent study of the characteristic X-ray radiation emitted by its elements.

Höchstleistung im Doppelpack
Mit der PM 100 und der PM 200 präsentiert Retsch eine neue Generation von Planeten-Kugelmühlen mit einer bzw. zwei Mahlstellen, die in diesem Produktsegment neue Leistungsstandards setzen.

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.