Aqueous lime slurry, preparation process and uses

Patent metadata

Field	Value
Publication number	US-9757685-B2
Application number	US-201314082253-A
Country	US
Kind code	B2
Filing date	Nov 18, 2013
Priority date	Nov 19, 2012
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

Preparation of aqueous slurries of calcium dihydroxide. Preparation of aqueous suspensions of calcium hydroxide.

First claim

The invention claimed is:

1. A process for the preparation of an aqueous slurry of calcium hydroxide, the process comprising:
agitating a mixture of water and a copolymer to form an aqueous solution;
adding powdered calcium hydroxide to said aqueous solution and agitating to provide an initial slurry;
applying a homogeneous shear level greater than 50,000 s −1 to the initial slurry; and
optionally, while applying said shear level to said initial slurry, adding more copolymer and/or more powdered calcium hydroxide to said initial slurry,
wherein said copolymer consists:
of methacrylic acid monomers and/or any of its salts,
optionally of acrylic acid monomers and/or any of its salts,
of one or more monomers with the formula (I):
R—X—R′   (I)

wherein:
R represents a polymerizable unsaturated group,
R′ represents hydrogen or an alkyl group with from 1 to 4 carbon atoms,
X represents a structure with n unit(s) of ethylene oxide EO and m unit(s) of propylene oxide PO, arranged randomly or regularly, and
m and n are independent non-zero integers and are between 1 and 150,
and wherein said process produces an aqueous slurry of calcium hydroxide with a dry content of at least 40% by weight, the viscosity of the aqueous slurry measured by a Brookfield DVIII viscometer at 10 RPM being between 25 and 1,000 mPa·s at 20° C.

2. The process according to claim 1 , wherein the copolymer has a molecular mass between 30,000 and 200,000 g/mol as determined by Gel Permeation Chromatography (GPC).

3. The process according to claim 1 , wherein the monomer of formula (I) is such that n+m 17.

4. The process according to claim 1 , wherein the R group of said monomer of formula (I) represents the methacrylate group.

5. The process according to claim 1 , wherein the R′ group of the monomer of formula (I) represents H or CH 3 .

6. The process according to claim 1 , wherein the monomer of formula (I) consists of, expressed as a percentage by weight of each of its components:
5 to 30% by weight of methacrylic acid monomers and/or any of its salts,
0 to 10% by weight of acrylic acid monomers and/or any of its salts,
70 to 95% by weight of monomers of formula (I).

7. The process according to claim 1 , wherein a mixer of the rotor-stator type is used to apply said shear.

8. The process according to claim 1 , wherein the shear is applied in a device equipped with a recirculating loop.

9. The process according to claim 1 , wherein the shear is applied in a device configured to deliver an output of at least 1,000 W/m 3 .

10. The process according to claim 1 , wherein the R group of said monomer of formula (I) represents an acrylate, methacrylate, methacrylurethane, vinyl or allyl group.

Assignees

• Coatex Sas

Inventors

• Belli Fabrizio
• Mongoin Jacques
• Berlendis Angelo

Classifications

• B01D53/1493

  Selection of liquid materials for use as absorbents · CPC title

• B01D53/64

  Heavy metals or compounds thereof, e.g. mercury · CPC title

• B01D53/502

  characterised by a specific solution or suspension · CPC title

• B01D2251/404

  of calcium · CPC title

• C01F11/02

  Oxides or hydroxides (production of lime C04B2/00) · CPC title