Method of making diatomaceous earth granulate
A method of making a diatomaceous earth granulate may include spray-drying a suspension including particles of diatomaceous earth, a liquid medium, and a binder, wherein inorganic solids in the suspension include at least 80 wt % diatomaceous earth. The method may further include recovering a diatomaceous earth spray-dried granulate. A granular diatomaceous earth product obtained by the method may include substantially spherical granules, each having a shell including diatomaceous earth surrounding a hollow core. The product may be used as a filter aid or in filtration.
1. A method of making a diatomaceous earth granulate, the method comprising:
spray-drying a suspension comprising particles of diatomaceous earth, a liquid medium, and a binder, wherein inorganic solids in the suspension comprise at least 80 wt % diatomaceous earth; and
recovering a diatomaceous earth spray-dried granulate.
2. The method according to claim 1 , wherein the solids in the suspension comprise at least 90 wt %.
3. The method according to claim 1 , wherein the binder is a temporary binder.
4. The method according to claim 1 , further comprising calcining the spray-dried granulate.
5. The method according to claim 1 , wherein the binder is a permanent binder.
6. The method according to claim 1 , further comprising:
forming the spray-dried granulate into a shaped body; and
calcining the shaped body.
7. The method according to claim 4 , wherein the calcining is carried out at a temperature of at least 600° C.
8. The method according to claim 4 , wherein the calcining is carried out at a temperature of at least 800° C.
9. The method according to claim 4 , wherein the calcining is carried out at a temperature of at least 900° C.
10. The method according to claim 6 , wherein the calcination is performed for no more than 4 hours at peak calcination temperature.
11. A granular diatomaceous earth product obtained by the method of claim 1 , wherein the granular diatomaceous earth product comprises substantially spherical granules, each having a shell comprising diatomaceous earth surrounding a hollow core.
12. The product according to claim 11 , wherein the granular diatomaceous earth product is in the form of a free-flowing granulate.
13. The product according to claim 11 , wherein the granules have a d 50 ranging from 10 μm to 250 μm.
14. The product according to claim 11 , wherein the granules have a d 50 ranging from 20 μm to 100 μm.
15. The product according to claim 11 , wherein the granular diatomaceous earth product has a permeability of at least 1.0 Da.
16. The product according to claim 11 , wherein the granular diatomaceous earth product has a permeability of at least 3.0 Da.
17. A diatomaceous earth product obtained by the method of claim 4 , wherein the said diatomaceous earth product comprises a mass of substantially spherical spray-dried granules formed into an integral body.
18. The diatomaceous earth product according to claim 17 , wherein adjacent granules in the body are sintered to each other.
19. A method of filtering a liquid comprising:
passing the liquid through a filter comprising the product according to claim 11 .
20. The method according to claim 19 , wherein the method is performed without the aid of a pre-coat.
21. A method of using a product according to claim 11 , the method comprising using the product as a filter aid or in filtration.
22. A method of filtering a liquid, the method comprising:
passing the liquid through a filter comprising at least one of granules of spray-dried diatomaceous earth or a shaped body formed from granules of spray-dried diatomaceous earth.