The reference material is always the cement which the Blaine specific surface and density are knew. These parameters will be used to determine de K of your Blaine apparatus. How you want to determine de surface specific area of others different powders materials, take care about the powders fineness normally higher than the cement. In this case, the problem is to define the value of e (porosity) to determine the sample mass to fill the cell. The e value needs to be fix for each powder type by trialling and verifying if the powder sample is well compacted with the plunger.

Thanks Luiz. I indeed have problems to prepare a compacted bed of fixed porosity when I use finer materials. For silica fume for example I haven't managed to do it yet. But it is referred that materials that have irregular shapes or a high internal porosity (cases of supplementary cementitious materials) can be characterized by air permeability methods if materials of the same nature are used for calibration. I suppose that by not using the appropriate reference material there will be wrong values for K value. Also it is referred by Niesel (1973) that for cements a powder bed should be compacted to a standard porosity which differs among various national standards. The one that I use (NBN EN196-6:2010) it is referring a compacted bed of porosity 0.5.

Dear Eleni,

It is truth that the Blaine surface area method is not the best to determine fineness of others powders materials than Portland cements. This method was developed to measure cement fineness and the surface specific area is calculated taking into account the regular shapes of cement particles as a spherical shape. Some researchers use BET or laser (Coulter apparatus) methods for higher fineness powders. However, you can use the Blaine method, independently of K precision, as a method to compare the powders fineness with the cement fineness. It will be a relative value. Even for others methods that are also questionable the results are relatives and couldn’t be comparables. I have been worked with some different powders as glass, metakaolin, ceramics, etc. In the beginning I was searching the standards samples to determine a new K for these materials, but I renounced. So, I continue to use the same K value calibrated with a standard cement sample and I am using together with Blaine method a laser method (Coulter apparatus). Comparing the results, by one and other method, I find that theirs are logical but not equal. Finally, I think that is not worth to worry about K. I hope that I have helped you instead of disturb you.

Dear Luiz,

of course and you have helped me a lot reading that you have already tested Blaine for different materials. I think I have come to the same conclusion as you, since I have also used laser diffractometer to determine fineness of cementitious materials (still have problems though measuring silica fume) and indeed found different results. I wasn't expecting though to find the same results since they are two different sizing techniques (air permeability test and laser diffraction) that can produce different results when measuring non-spherical particles. So, I think that the Blaine method achieves only comparative specific surfaces (and not absolute ones, nor particle size distribution).

Dear Eleni

I would like to intervene to this very interesting discussion. I absolutely agree that the reference material is always the cement where the Blaine specific surface and density are known. In this way the k of the apparatus is found. Then for other materials it is important to find a convenient porosity to be well compacted the bed. Then you apply the formula (2) of EN 196-2. For the laser technique if the particles are supposed spherical, you can calculate the specific surface by applying the formula:

S=Σ 6ρwi/di from i = 1 to N where ρ=density, di the size and wi the mass fraction on this size. You will find that the sizes up to 3-4 microns contribute significantly to the spec. surface. Then you can make a regression between Spec. surface measured by blaine apparatus and laser and you find a coefficient k1 (S_Bl=k1*S_Las) which will characterize the material. This relation could be used to calculate the Blaine of the material from the particle size distribution with laser.

To mention always that both methods are relative and comparative and can be used in quality control, to check the stability of the process. I think you find this idea useful and I do not disturb you

Dear Dimitris, thank you very much for your extended explanation here. After having worked on Blaine I came to the conclusion that this test is not appropriate for very fine materials since you can't successfully form a bed of the desired 0.5 porosity by using the mass calculated by the formula in EN 196-2 standard. On the other hand if you try several mass quantities in order to form a bed by adjusting properly the plunger into the cup, then you must recalculate the porosity of the bed you have formed from the formula given in the same standard for porosity bed different than 0.5. In that case you use the K value and the volume calibrated for a bed of 0.5 and I am not sure if this is right to do. I trust more the results from laser diffraction although there are still some assumptions made that are not true for all materials.

is anyone has blaine calulation of any sample basically cement and flyash in excel spreadsheet or in word doc. or pdf format?

also is it applicable that for flyash and cement blaine determination,a standard blaine of portland slag cement should be taken or simply any standard opc cement blaine can be used?

Blaine apparatus was studied  for more than 19 years by various undergraduate students

the result

1. bed porosity should be accurately estimated by having excess powder  so that plunger will will project outside. First to find by conventional method bed porosity of OPC and PPC cement is different due to presence of mixed shapes particles ( fly ash and cement)..

2. Sphericity ( shape of powder) is estimated

3, Size distribution can be estimated

5. Flowability is measured

6. Specific surface of  various materials like cement, fly ash, more than 200 pharma powder, food powders like spices, metal powders were measured..

7. estimated amount of fly ash in cement

8. Estimated percentage of unburnt coal in fly ash

Above study made with Blaine Apparatus and introduced to the various industries to estimate finesse of powder.