Bentonite Particle Size

Dry sieving is placing the material on a sieve screen and activating the sieving unit. For wet sieving, water (or other suitable dispersing agent) is continuously added to the sieving stack to aid in flushing material through the sieves. Wet sieving is commonly used for light, flakey materials or those with a tendency for having a high static charge which may cause the material to stick to the sides of the sieve stack. If you have questions or are in need of further info, contact Eric: info@labsynergy.com

The material we are testing is Bentonite. I ran a test yesterday with wet screen and had 99.5% passing. Using the same sample I ran a dry seive and had results of 89% passing. Weighing the material passing and weighing the residue left I was short a very small amount of material. By what you were saying thats why we would use a wet screen for this type of material.

Any thoughts

jasons

my experience has indicated wet screening to always be more accurate....reproducibility of results on a given sample will confirm this.

btw

can you please give me any clues in making a slurry of bentonite in water... i have trouble getting uniform wetting above about 5% by stir in.

thanks

As informed to you earlier, Bentonite has a static charge on the sample, so they tend to agglomerate, however in wet seiving we have various opportunities to de-agglomerate the sample or in other words we can wet the sample by adding suitable surfactants, and make a slurry of bentonite, and introduce the same in the seiving apparatus. I further wish to inform you that I head the knowledgement management team at Aimil Limited Bangalore. where we have the faclity of latest Application Centre for Particle Sizing. In case you need further assistance, please let me know.

Adil. (kaadil@aimil.com)

This seems to be confused.

Bentonite is one of many clay therefore would not be retained in any screen...therefore you need to use a hydrometer to ascertain whether silt or clay.

If it does not disaggregate to a clay size particle then maybe it is not a "soil" but a rock = bentonitic shale.

Jason,

How ever the guest is told you exactly correct. The clay particles are like a peice of paper only microscopic in length. They can be highly static when dry and when in water they are held in suspension by simular force call vanderwall's forces. That's why the Mississippi River is so muddy. It's the clay. Bentonite is some of the most "fat" clay you can get. I hope you don't have to run atterburg limits on that stuff. It will soak up 3 times it's wieght in water. and swell 300% to 400%. It is great for waterproofing buildings and dams, bad under building slabs and foundations

I rated this as a good answer.

Bentonite clays are used for water well drilling exactly because they exhibit these properties. The swelling of the clays will allow the hydrostatic pressure in the borehole to form a cake on the wall surface and preclude collapse of the borehole.

Microtrack..........Microtrack............Microtract.