HIGH PERMEABILITY COMPOSITE MAGNESIUM SILICATE FILTER AIDS
A composite filter aid may include a silicate substrate and a precipitated magnesium silicate having a mole ratio of SiO 2 :MgO greater than about 1.0:1. A method for making a composite filter aid may include providing a silicate substrate, precipitating a magnesium silicate onto the silicate substrate to form a composite filter aid, wherein the mole ratio of SiO 2 :MgO of the magnesium silicate is greater than about 1.0:1. A method for filtering a non-aqueous liquid may include providing a non-aqueous liquid for filtering and filtering the non-aqueous liquid through a composite filter aid.
1 . A composite filter aid comprising:
a silicate substrate and a magnesium silicate precipitated on the silicate substrate,
wherein the mole ratio of SiO 2 :MgO of the precipitated magnesium silicate is greater than about 1.0:1.
2 . The filter aid of claim 1 , wherein the silicate substrate comprises biogenic silica.
3 . The filter aid of claim 1 , wherein the silicate substrate comprises diatomite.
4 . The filter aid of claim 1 , wherein the precipitated magnesium silicate comprises an amorphous magnesium silicate.
5 . The filter aid of claim 1 , wherein the precipitated magnesium silicate is in a range from about 5% to about 80% by weight of the composite filter aid.
6 . The filter aid of claim 1 , wherein the silicate substrate is chosen from the group consisting of perlite, pumice, volcanic ash, calcined kaolin, smectite, mica, talc, shirasu, obsidian, pitchstone, rice hull ash, and combinations thereof.
7 . The filter aid of claim 1 , wherein the composite filter aid has a mole ratio of SiO 2 :MgO greater than or equal to about 4.0:1.
8 . The filter aid of claim 1 , wherein the composite filter aid has a d 50 in a range from about 40 to about 300 microns.
9 . The filter aid of claim 1 , wherein the composite filter aid has a permeability in a range from about 100 md to about 3000 md.
10 . The filter aid of claim 1 , wherein the composite filter aid has a BET surface area in a range from about 25 m 2 /g to 440 m 2 /g.
11 . The filter aid of claim 1 , wherein the composite filter aid has a BJH pore volume (1.7 nm to 300 nm) in a range from about 0.05 cm 3 /g to about 0.25 cm 3 /g.
12 . The filter aid of claim 1 , wherein the precipitated magnesium silicate has a median pore volume in a range from about 0.1 to about 0.5 cm 3 /g.
13 . The filter aid of claim 1 , wherein the precipitated magnesium silicate has a median pore diameter in a range from about 5 to about 15 nm.
14 . A method for making a composite filter aid, the method comprising:
providing a silicate substrate; and
precipitating a magnesium silicate onto the silicate substrate to form a composite filter aid,
wherein the mole ratio of SiO 2 :MgO of the precipitated magnesium silicate is greater than about 1.0:1.
15 . (canceled)
16 . The method of claim 14 , wherein the silicate substrate comprises biogenic silica.
17 . (canceled)
18 . The method of claim 14 , wherein precipitating the precipitated magnesium silicate comprises precipitating a magnesium silicate coating on the silicate substrate.
19 . The method of claim 14 , wherein the amount of the precipitated magnesium silicate is in a range from about 5% to about 80% by weight of the composite filer aid.
20 - 26 . (canceled)
27 . A method for filtering a non-aqueous liquid, the method comprising:
providing a non-aqueous liquid for filtering; and
filtering the non-aqueous liquid through a composite filter aid,
wherein the composite filter aid comprises a silicate substrate and a precipitated magnesium silicate, wherein the mole ratio of SiO 2 :MgO in the precipitated magnesium silicate is greater than about 1.0:1.
28 . The method of claim 27 , further comprising, prior to filtering the non-aqueous liquid, pre-coating a filter structure with the composite filter aid.
29 . The method of claim 27 , wherein providing the non-aqueous liquid comprises adding the composite filter aid as a body feed in the non-aqueous liquid.
30 . The method of claim 27 , wherein the non-aqueous liquid comprises a biodiesel.
31 . The method of claim 27 , wherein the non-aqueous liquid comprises an edible oil.
32 - 39 . (canceled)