Hi there,
we want to press pellets from different soil samples (powdered in advance) in order to use them for total element analysis via XRF.
In advance, we tried to produce pellets from certified reference material which is very finely powdered. We used Licowax Micropowder as binding addidive but never got satisfying results after homogenization - there were always white dots (wax) remaining. We used both homogenization "by hand" in a mortar and homogenization in a Retsch Mixer Mill (30 min., frequency: 20, using agate balls).
Can anyone suggest a good way of preparing XRF pellets from reference material (e.g. sewage sludge) or natural soil samples?
Thank you in advance!
You should add the cellulose to your reference material fifty fifty. And then mix them in 10 minutes. I suppose it will be homogenized.
What about try to mechanically homogenize the samples in liquid N2 medium?
Thank you both for your answers.
Mr. Köksal., we need to mix them in a ratio sample:wax = 5:1. How do you homogenize your pellets - by hand in a mortar or with a mixer mill?
Mr. Normakhamatov, is using liquid N2 medium to typical for homogenization? I have never heard of that for the daily routine...?
Dear Mr. Sirin,
thank you very much for the documents - I was looking for such a guideline. I will go for it as described - thanks a lot again!
Teresa Zahoransky
Is using liquid N2 medium to typical for homogenization? I have never heard of that for the daily routine...?
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It is one trick when you work with some non solid samples when you need to get fine powdered form in the result. As you said "there were always white dots (wax) remaining", wax will be in solid form as much as possible in frozen state (in liquid N2 medium) and more easily homogenized and mix equaly when you mill it with soil samples.
You may dry wax in an oven so you will get it as powder. Finally you mix it with your sample. But I am not sure.
Sometimes mixing the dry sample with 10 % grinded boric acid is enough. Another solution for difficult samples is mixing with a solution of a resin (Elvacite or similar) at 10 % in acetone. While you are mixing in a mortar, the acetone evaporates and you get a pretty homogenized mixture. You can dry it in a oven. It works pretty well in difficult samples.
Dear Mr. Carvajal,
thank you very much for that suggestion. That sounds interesting - I will give it a try!
Dear Teresa
We make press pellet using Boric acid powder with ratio of 15 to 20%. We mix them mechanically not by hand. We apply this method for steelmaking, iron pellet and sponge iron analysis with XRF.
Good luck
Dear Teresa,
We used to make pellets of different slag and related samples using Boric acid powder pressed in a hydraulic press. The proportion of making pellets can be taken as 80% sample and 20% Boric acid powder; proper homogeneous mixture shall be done of both the ingredients before making pellets.
Hope it helps
with regards
You can use cellulose powder (10% wt/wt) as a binder to prepare pellets from soil samples for X ray fluorescence spectrometry (XRF).
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