LOW SOLUBLE ARSENIC DIATOMITE FILTER AIDS
Low soluble arsenic diatomite filter aids and method of making such filter aids are disclosed. Alumina and/or aluminum hydroxide (ATH) are used as additives when preparing the filter aids, which may be straight-calcined or flux-calcined. Alternatively, activated alumina may be added to an already straight-calcined or flux-calcined diatomite filter aid. As compared to either straight-calcined or soda ash flux-calcined diatomite filter aids of similar permeabilities made from the same ore, the disclosed filter aids have lower soluble arsenic content. The disclosed filter aids have a soluble arsenic content, either by the OIV, EBC or USFCC method, of about 60% or less than the straight or flux-calcined diatomite filter aids of similar permeability without an alumina or ATH additive.
1 . A straight-calcined diatomite filter aid comprising:
diatomite;
an aluminum additive selected from the group consisting of alumina and aluminum hydroxide (ATH); and
a soluble arsenic content as analyzed by a method selected from the group consisting of
an International Oenological Codex, by Organisation Internationale de la Vigne et du Vin (OIV), soluble arsenic content of less than about 3 ppm;
a European Brewing Convention (EBC) soluble arsenic content of less than about 10 ppm;
a United States Food Chemical Codex (USFCC) soluble arsenic content of less than about 10 ppm; and
combinations thereof.
2 . The straight-calcined diatomite filter aid of claim 1 , wherein the OIV soluble arsenic content is less than about 1 ppm.
3 . The straight-calcined diatomite filter aid of claim 1 , wherein the EBC soluble arsenic content is less than about 5 ppm.
4 . The straight-calcined diatomite filter aid of claim 1 , wherein the USFCC soluble arsenic content is less than about 5 ppm.
5 . The straight-calcined filter aid of claim 1 wherein the aluminum additive is ATH, which has a median particle diameter exceeding about 15 microns.
6 . The straight-calcined filter aid of claim 1 wherein the aluminum additive is alumina, wherein further the alumina is activated alumina.
7 . A flux-calcined diatomite filter aid comprising:
diatomite;
an alkali metal flux agent;
an aluminum additive selected from the group consisting of alumina and aluminum hydroxide (ATH); and
a soluble arsenic content as analyzed by a method selected from the group consisting of
an International Oenological Codex, by Organisation Internationale de la Vigne et du Vin (OIV), soluble arsenic content of less than about 3 ppm;
a European Brewing Convention (EBC) soluble arsenic content of less than about 10 ppm;
a United States Food Chemical Codex (USFCC) soluble arsenic content of less than about 10 ppm; and
combinations thereof.
8 . The flux-calcined diatomite filter aid of claim 7 wherein the OIV soluble arsenic is less than about 1 ppm.
9 . The flux-calcined diatomite filter aid of claim 7 wherein the EBC soluble arsenic is less than about 5 ppm.
10 . The flux-calcined diatomite filter aid of claim 7 wherein the aluminum additive is ATH, which has a median particle diameter exceeding about 15 microns.
11 . The flux-calcined diatomite filter aid of claim 7 wherein the aluminum additive is alumina, wherein further the alumina is activated alumina.
12 . The flux-calcined diatomite filter aid of claim 7 wherein the alkali metal fluxing agent is selected from the group consisting of an alkali metal carbonate, a halide and combinations thereof.
13 . The flux-calcined diatomite filter aid of claim 7 wherein the alkali metal fluxing agent is soda ash.
14 . A method for preparing a straight-calcined diatomite filter aid product comprising:
providing at least one of alumina and aluminum hydroxide (ATH) and diatomite;
mixing the at least one of alumina and ATH with the diatomite to form a mixture; and
calcining the mixture at a temperature ranging from about 900° C. to about 1200° C. to produce the diatomite filter aid product having a soluble arsenic content as analyzed by a method selected from the group consisting of
an International Oenological Codex, by Organisation Internationale de la Vigne et du Vin (OIV), soluble arsenic content of less than about 3 ppm;
a European Brewing Convention (EBC) soluble arsenic content of less than about 10 ppm;
a United States Food Chemical Codex (USFCC) soluble arsenic content of less than about 10 ppm; and
combinations thereof.
15 . The method of claim 14 wherein the OIV soluble arsenic content of the calcined diatomite filter aid product is less than about 1 ppm.
16 . The method of claim 14 wherein the EBC soluble arsenic content of the calcined diatomite filter aid product is less than about 5 ppm.
17 . The method of claim 14 wherein the USFCC soluble arsenic content of the calcined diatomite filter aid product is less than about 5 ppm.
18 . The method of claim 14 wherein the diatomite filter aid product has a permeability of less than about 1 Darcy.
19 . The method of claim 14 wherein the alumina or ATH is present in the mixture in an amount of less than about 10 wt %.
20 . A method for preparing a flux-calcined diatomite filter aid product comprising:
providing at least one of alumina and aluminum hydroxide (ATH);
providing an alkali metal flux agent and a diatomite;
mixing at least one of alumina and ATH with the flux agent and the diatomite to form a mixture; and
calcining the mixture at a temperature ranging from about 900° C. to about 1200° C. to produce the diatomite filter aid product having a soluble arsenic content as analyzed by a method selected from the group consisting of
an International Oenological Codex, by Organisation Internationale de la Vigne et du Vin (OIV), soluble arsenic content of less than about 3 ppm;
a European Brewing Convention (EBC) soluble arsenic content of less than about 10 ppm;
a United States Food Chemical Codex (USFCC) soluble arsenic content of less than about 10 ppm; and
combinations thereof.
21 . The method of claim 20 wherein the OIV soluble arsenic content of the flux-calcined diatomite filter aid product is less than about 1 ppm.
22 . The method of claim 20 wherein the EBC soluble arsenic content of the flux-calcined diatomite filter aid product is less than about 5 ppm.
23 . The method of claim 20 wherein the diatomite filter aid product has a permeability of less than about 10 Darcy.
24 . The method of claim 20 wherein the alumina or ATH is present in the mixture in an amount of less than about 10 wt %.
25 . A method for preparing a calcined diatomite filter aid product comprising:
providing activated alumina;
providing a calcined diatomite;
mixing the activated alumina and the calcined diatomite to form a mixture that is a diatomite filter aid product with a soluble arsenic content as analyzed by a method selected from the group consisting of
an International Oenological Codex, by Organisation Internationale de la Vigne et du Vin (OIV), soluble arsenic content of less than about 3 ppm;
a European Brewing Convention (EBC) soluble arsenic content of less than about 10 ppm;
a United States Food Chemical Codex (USFCC) soluble arsenic content of less than about 10 ppm; and
combinations thereof.
26 . The method of claim 25 wherein the calcined diatomite is a straight calcined diatomite.
27 . The method of claim 25 wherein the calcined diatomite is a flux-calcined diatomite.
28 . The method of claim 25 wherein the activated alumina is present in the mixture in an amount of less than about 10 wt %.