# Blaine vs Residues

November 5, 2019 | Author: Anonymous | Category: Particle Size Distribution, Mill (Grinding), Cement, Nature

#### Description

Blaine vs Residues 1 Introduction -

This short presentation will detail the relationship between Blaine fineness and the resi of a given Portland cement. Other materials such as raw meal or fly ash will be mentioned as examples. To the question to know if there is a direct relationship between Blaine and residue, the YES. When the Blaine increases, the residue on a given sieve decreases. On the contrary, if the Blaine decreases, the residue on a given screen increases. And there are the exceptions that prove the rule. Here is an example of good relationship between Blaine and the residue for fly ash:

2 Blaine -

-

The fineness of cement is measured as specific surface area. This is called the Blaine specific surface. The specific surface area is expressed by the total of the surface area in square centim cement particles beeing in one cement gram. The units used are generally: cm2/gr and also m2/kg Some usual values of Blaine:

3 Residue -

-

It is the cumulated residue on a given sieve. The most widely used reference sieves are: * For cement: 32 microns, 45 microns, 63 microns, 90 microns * For raw meal: 90 microns, 200 microns In the past, the sieve more used for the Portland cement was 90μ. Now, the 45μ sieve is more used. Intervals of common residues:

4 Blaine - residue correspondence -

In the past, there were some classic references on Blaine-residue correspondence. This was before the emergence of high-efficiency separators. The most famous is:

-

Currently, high-efficiency separators rather give this:

-

The high-efficiency separators produce a narrower particle size distribution. This means that the slope of the line on the graph RRSB will be more vertical. These are the typical slopes of the separators on the RRSB diagram:

5 Influence of high-efficiency separator -

As already mentioned above, the high-efficiency separators modify the particle size dis the cement. Below, a comparison between a cement produced with a first generation separator and efficiency separator:

www.thecementgrindingoffice.com -

-

In this Rosin-Rammler diagram, percentages of passing cumulated on 7 very interesting determined: * Sieve of 1 µ: ultrafine particles (0-2μ) which don't participate in resistance, but bring t * Sieve of de 2 µ: the particles larger than this size begin to bring the resistance * Sieve of 8 µ: that sieve gives a good idea of the Blaine for an OPC clinker/gypsum cem * Sieves of 32 µ, 45 µ, 63 µ et 90 µ: these are the reference sieves in cement plants Below, the table with the passing of the diagram:

-

-

-

-

The diagram shows that the red line (cement with 3rd generation separator) is narrowe vertical. The blue line (cement with separator of 1st generation) has more passing in the range from 13 μ, it has more residue. The red line has more passing than the blue line in the range 13-32 μ which brings the of resistances. Finally, if we multiply the percentage of passing on 8μ by 100, one obtains: * Blue Line (cement with 1st generation separator): 3180 * Red Line (cement with 3rd generation separator): 3000 The two figures obtained very often give a good estimation of the Blaine, but only in th cement with clinker + gypsum. The cement produced with an old separator therefore will probably have a higher Blaine residues on the reference sieves.

6 Influence of limestone and natural pozzolana -

-

These two additives often used for the final production of cement bring what is general false Blaine. With limestone or pozzolana, cement has a wider distribution (less vertical) with more u particles. The false Blaine would be 40-50 Blaine per percentage of limestone or pozzolana in the That is why the raw mills grinding limestone have a lower retention time and a higher c of the separator. This is to remove the very fine limestone particles as soon as possible of the circuit in o the production of overfines which are useless. Do not forget that the target of producing raw meal is not to have Blaine but only to ge a certain sieve.