Silica slurry sop?

So I’m the new guy here…lol anyway. I’m gonna try winterizing a little better… I have a buchner and 90mm filter paper coffee filters celite 545, mag-sil ,and cbleech… I’m going to wanna make a silica slurry first. … never made a cake before… anyone have time to walk me thru it… this batch is pretty dark so I wanna lighten it up… before I spd… I baked the column when extracted and now she looks pretty dark…I added 10.1 ethoand I put it in the freezer for 3 days… and it’s pretty separated at this point… Silica slurry seems to be my next filteration?

Did you do a room temp filtration first? You might be walking into a nightmare of a clog in your filtration.
I would use the filter aids after you’ve done all your rough filtration, save the celite and such for the final filtration.
you can load your filter aids as a slurry or by drypacking.
To drypack:

  1. wet a filterpaper with a small amount of the solvent your are useing and turn on the vacuum source, make sure there aren’t any leaks around the edges of the filter. This is critical.
  2. Add your filter aids with a scoopula into the funnel, do not stop the vacuum draw at any point.
    3)with a clean dowl rod pack the powder firmly untill “hard packed” make sure to pack the edges well.
  3. With the suction on wash the filtercake with some solvent. Observe the filtrate, inspect it for any filter aids that may have gotten around the filter paper. Observe the surface of the filter cake, it should not exibit signs of errosion, if the top layer is loose you havent packed it hard enough.

to wet load:

  1. seat a filterpaper just like the dryload.
  2. make a slurry of solvent and filter aid in a seporate beaker.
    3)with the suction on and the paper seated, take the filteraid slurry beaker and swirl it untill all the solids are suspended. Quickly pour this into the funnel, the suction should do the rest.

I like to add approx. 600ml of ethanol to 75 grams of silica, mix with glass stir rod, have vacuum pulling on funnel, pour silica solution over funnel continue pulling vac until most all ethanol is through the funnel and the cake is sitting evenly on the bottom of the funnel. Then pour crude ethanol solution over silica bed slowly trying not to make holes in the bed. You should filter for fats before filtering with silica.


I did filter it with the coffee filter first then 90mm filter paper then froze it for three days and refiltered this morning with the 90mm again… then was gonna just rotovap it but decided to put back in the freezer and filter more… so I would figure I’m ready to silica filter… correct ?

yes, if you removed the bulk of the junk your good to go. let us know how it went!

Question: what do you mean when you say “I baked the column when extracted…”?

You talking about closed loop?

Yes. . Typically I would freeze the dewax sleeve with dry ice. Instead I froze the material and used chilled solvent and blasted then used hot water in my dewax sleeve and cooked out the leftover solvent… worked pretty good… the material seemed really dry but it made my crude look darker.

Seems to have worked fine…

Hi - thanks for all the great info… do you mix celite and silica together for the slurry? Or do you put elite down then put the silica on the top?

usually used in layers, not mixed.