Filter aids made from low permeability diatomites
Disclosed herein are diatomite filter aid products with enhanced permeabilities and flow characteristics, and methods for enhancing the permeabilities and flow characteristics of very fine grain, low permeability diatomite ore by, in one embodiment, pre-agglomerating the ore in the presence of less than 10% water and then subjecting the pre-agglomerated ore to at least one calcination process. At least one flux may be used in the at least one calcination process. Also disclosed herein is a method of processing diatomite ore suitable for samples with high wet densities or large amounts of fine particulate matter. Also disclosed herein are methods of producing commercially applicable filter aid products from Hungarian diatomite.
1. A method for preparing a diatomite filter aid product comprising:
a. providing at least one diatomite feed material having a wet density greater than about 25 lb/ft 3 and a permeability less than about 0.010 Da;
b. pre-agglomerating the at least one diatomite feed material with from about 3 to about 10% water to produce a pre-agglomerated diatomite, the pre-agglomerated diatomite being particulate; and,
c. calcining the pre-agglomerated diatomite,
wherein the calcined diatomite has a wet density less than about 25 lb/ft 3 and a permeability greater than about 0.050 Da.
2. The method of claim 1 , further comprising passing the pre-agglomerated diatomite through at least one screen.
3. The method of claim 1 , wherein the pre-agglomerated diatomite is calcined in the presence of at least one fluxing agent.
4. The method of claim 3 , wherein the at least one fluxing agent is soda ash.
5. The method of claim 3 , wherein the at least one fluxing agent is present in an amount of less than about 10%.
6. The method of claim 1 , wherein from about 3 to about 6% water relative to the weight of the feed material is added to the at least one diatomite feed material during pre-agglomerating.
7. The method of claim 1 , further comprising treating the calcined pre-agglomerated diatomite with water.
8. The method of claim 2 , wherein the openings of the at least one screen are from about 150 to about 1410 microns.
9. The method of claim 8 , wherein the openings of the at least one screen are from about 500 to about 1410 microns.
10. The method of claim 1 , wherein the at least one diatomite feed material has a wet density greater than about 28 lb/ft 3 .
11. The method of claim 1 , wherein the calcined diatomite has a wet density less than about 22 lb/ft 3 .
12. The method of claim 1 , wherein the calcined diatomite has a Beer Soluble Iron content of less than about 35 ppm.