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US 5,223,239 AGranted
Method of preparing hydrated lime
AssigneeResearch Corporation Technologies, Inc.
InventorsDavid L. Moran, Massoud Rostam-Abadi
Life of this patent
Estimating the term…
Abstract
Hydrated lime having high surface area and small particle size is prepared by hydrating lime with an aqueous hydration solution of an organic solvent, and preferably washing the resulting hydrate with an aqueous solution of an organic solvent prior to drying. The high surface area hydrates of the invention are excellent sorbents for SO.sub.2 removal from gas streams.
Claims74
A method of preparing hydrated lime comprising the steps of:
- (a) thoroughly mixing lime, at a temperature sufficiently low to produce a homogeneous slurry prior to hydration of said lime, with an aqueous hydration solution of an organic solvent which has a boiling point less than that of water and which retards the rate of hydration of said lime, to produce a homogeneous slurry, said solution containing an amount of water less than about two times the stoichiometric amount of water relative to said lime yet sufficient to provide a desired degree of hydration and at least about 0.5 volume of said organic solvent per volume of water, said lime being prepared by calcining limestone to directly produce said lime;
- (b) introducing the slurry of step (a) to a hydrator comprising a single vessel which is free of internal physical separations;
- (c) at least partially hydrating said lime at a temperature sufficiently high to cause hydration of said lime to produce a partially hydrated lime paste;
- (d) hydrating said paste further at the boiling point of said hydration solution to produce a hydrated lime powder;
- and,
- (e) drying said powder to produce a hydrated lime product, at least said steps (b)-(d) being carried out in said vessel of (b).
3 more elements
A method of preparing hydrated lime comprising the steps of:
- (a) thoroughly mixing lime, at a temperature sufficiently low to produce a homogeneous slurry prior to hydration of said lime, with an aqueous hydration solution of an organic solvent which has a boiling point less than that of water and which retards the rate of hydration of said lime, to produce a homogeneous slurry, said solution containing an amount of water less than two times the stoichiometric amount of water relative to said lime yet sufficient to provide a desired degree of hydration and at least about 0.5 volume of said organic solvent per volume of water, said lime being prepared by calcining limestone to directly produce said lime;
- (b) introducing the slurry of step (a) to a hydrator comprising at least a preheating stage and a paste mixing stage;
- (c) at least partially hydrating said lime at a temperature sufficiently high to cause hydration of said lime to produce a partially hydrated lime paste;
- (d) hydrating said paste further at the boiling point of said hydration solution to produce a hydrated lime powder;
- (e) washing said hydrated lime powder in an aqueous washing solution comprising an organic solvent at a temperature sufficiently low to inhibit recrystallization of said hydrated lime;
- and,
- (f) separating and drying said hydrated lime to produce a hydrated lime product.
4 more elements
A method of preparing hydrated lime comprising the steps of:
- (a) thoroughly mixing lime, at a temperature sufficiently low to produce a homogeneous slurry prior to hydration of said lime, in a mixing stage with an aqueous hydration solution of an organic solvent which has a boiling point less than that of water and which retards the rate of hydration of said lime, to produce a homogeneous slurry, said solution containing an amount of water less than two times the stoichiometric amount of water relative to said lime yet sufficient to provide a desired degree of hydration and at least about 0.5 volume of said organic solvent per volume of water, said lime being prepared by calcining limestone to directly produce said lime;
- (b) introducing the slurry of step (a) to a hydrator comprising at least a preheating stage and a paste mixing stage;
- (c) at least partially hydrating said lime at a temperature sufficiently high to cause hydration of said lime to produce a partially hydrated lime paste;
- (d) hydrating said paste further in said paste mixing stage at the boiling point of said hydration solution to produce a hydrated lime powder;
- and,
- (e) drying said powder in a drying stage to produce a hydrated lime product, at least said steps (b)-(d) being carried out in a single vessel.
3 more elements
A method of preparing hydrated lime comprising the steps of:
- (a) thoroughly mixing lime, at a temperature sufficiently low to produce a homogeneous slurry prior to hydration of said lime, in a mixing stage with an aqueous hydration solution of an organic solvent which has a boiling point less than that of water and which retards the rate of hydration of said lime, to produce a homogeneous slurry, said solution containing an amount of water less than about two times the stoichiometric amount of water relative to said lime yet sufficient to provide a desired degree of hydration and at least about 0.5 volume of said organic solvent per volume of water, said lime being prepared by calcining limestone to directly produce said lime;
- (b) introducing the slurry of step (a) to a hydrator comprising at least a preheating stage and a paste mixing stage;
- (c) at least partially hydrating said lime at a temperature sufficiently high to cause hydration of said lime to produce a partially hydrated lime paste;
- (d) hydrating said paste further in said paste mixing stage at the boiling point of said hydration solution to produce a hydrated lime powder;
- (e) washing said hydrated lime powder in an aqueous washing solution comprising an organic solvent at a temperature sufficiently low to inhibit recrystallization of said hydrated lime;
- and
- (f) separating and drying said hydrated lime to produce a hydrated lime product, at least said steps (b)-(d) being carried out in a single vessel.
4 more elements
A method of preparing hydrated lime comprising the steps of:
- (a) thoroughly mixing lime, at a temperature sufficiently low to produce a homogeneous slurry prior to hydration of said lime, with an aqueous hydration solution of an organic solvent which has a boiling point less than that of water and which retards the rate of hydration of said lime, to produce a homogeneous slurry, said solution containing an amount of water less than two times the stoichiometric amount of water relative to said lime yet sufficient to provide a desired degree of hydration and at least about 0.5 volume of said organic solvent per volume of water, said lime having a surface area of at least about 2.5 m.sup.2 /g and being prepared by calcining limestone to directly produce said lime;
- (b) introducing the slurry of step (a) to a hydrator comprising a paste mixing stage;
- (c) hydrating said lime in said paste mixing stage at the boiling point of said hydration solution to produce a hydrated lime powder;
- and,
- (d) drying said powder to produce a hydrated lime product, said steps (a)-(c) being carried out without the application of heat from a source external to said hydration reaction.
2 more elements
A method of preparing hydrated lime comprising the steps of:
- (a) thoroughly mixing lime, at a temperature sufficiently low to produce a homogeneous slurry prior to hydration of said lime, with an aqueous hydration solution of an organic solvent which has a boiling point less than that of water and which retards the rate of hydration of said lime, to produce a homogeneous slurry, said solution containing an amount of water less than two times the stoichiometric amount of water relative to said lime yet sufficient to provide a desired degree of hydration and at least about 0.5 volume of said organic solvent per volume of water, said lime having a surface area of at least about 2.5 m.sup.2 /g and being prepared by calcining limestone to directly produce said lime;
- (b) introducing the slurry of step (a) to a hydrator comprising a paste mixing stage;
- (c) hydrating said lime in said paste mixing stage at the boiling point of said hydration solution to produce a hydrated lime powder;
- (d) washing said hydrated lime powder prior to drying in an aqueous washing solution comprising an organic solvent at a temperature sufficiently low to inhibit recrystallization of said hydrated lime;
- and,
- (e) separating and drying said hydrated lime to produce a hydrated lime product, said steps (a)-(c) being carried out without the application of heat from a source external to said hydration reaction.
3 more elements
A method of preparing hydrated lime comprising the steps of:
- (a) thoroughly mixing lime, at a temperature sufficiently low to produce a homogeneous slurry prior to hydration of said lime, with an aqueous hydration solution of an organic solvent which has a boiling point less than that of water and which retards the rate of hydration of said lime, to produce a homogeneous slurry, said solution containing an amount of water less than about two times the stoichiometric amount of water relative to said lime yet sufficient to provide a desired degree of hydration and at least about 0.5 volume of said organic solvent per volume of water, said lime having a surface area of at least about 2.5 m.sup.2 /g and being prepared by calcining limestone to directly produce said lime;
- (b) introducing the slurry of step (a) to a hydrator comprising a paste mixing stage;
- (c) hydrating said lime in said paste mixing stage at the boiling point of said hydration solution to produce a hydrated lime powder;
- and,
- (d) drying said powder to produce a hydrated lime product, wherein all of said organic solvent and less than all of said water of said hydration solution are mixed with said lime to form said slurry of step (a) and the remainder of said hydration solution water is introduced to said hydrator separately from said slurry.
2 more elements
Dependencies are inferred from the claim text.