Method for producing a highly porous fine powdered slaked lime composition, and product obtained therefrom

Patent metadata

Field	Value
Publication number	US-10934210-B2
Application number	US-201716309783-A
Country	US
Kind code	B2
Filing date	Jun 23, 2017
Priority date	Jun 24, 2016
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

The present invention relates to a method for producing a highly porous fine powdery slaked lime composition, comprising a fluidification step for forming said highly porous fine powdery slaked lime composition having an Alpine fluidity greater than 50% and which is carried out in a dryer/grinder chosen from the group consisting of a pin-type dryer/grinder, a cage-type dryer/grinder, an instantaneous dryer/disagglomerator and a combination of these until the powdery slaked lime composition has a non-solid residual-phase content of less than or equal to 3.5% by weight and greater than or equal to 0.3% by weight, as well as the product obtained therefrom.

First claim

The invention claimed is:

1. Method for producing a highly porous fine powdery slaked lime composition, comprising the steps consisting of:
introducing quicklime into a feeding zone of a hydrator,
introducing water into the feeding zone of the hydrator;
slaking said quicklime in a slaking zone of the hydrator by means of a quantity of water that is sufficient to obtain a slaked lime having a non-solid residual-phase content of between 15% and 55% by weight;
drying and grinding said slaked lime in order to form the powdery slaked lime composition, characterised in that said drying and grinding steps are performed simultaneously and are a single step of fluidification of the slaked lime in order to form said fine and highly porous fine powdery slaked lime composition having an Alpine fluidity greater than 50%, the Alpine fluidity AF being defined by the equation

AF
=

m
i

-

m

R
⁢

90

⁢

(

T
15

;

⁢

P
100

)

m
i

-

m

R
⁢

90

⁢

(

T
120

;

⁢

P
150

)

·
100

where:
m 1 is the is the initial mass of 50 g of powder distributed over a 90 μm sieve;
m R90(T15; P100) is the mass of residues of material on the sieve after 15 seconds with a negative pressure at 100 mm of manometric liquid of density 0.88;
m R90(T120; P150) is the mass of residues of material on the sieve after 15 seconds with a negative pressure at 100 mm of manometric liquid of density 0.88 and after 120 seconds with a negative pressure at 150 mm of manometric liquid of density 0.88;

said drying and grinding steps being carried out in a drier/grinder selected from the group consisting of a pin-type dryer/grinder, a cage-type dryer/grinder, an instantaneous dryer/disagglomerator and a combination of these until the highly porous fine powdery slaked lime composition has a residual non-solid phase content, measured by a loss-on-ignition test at 180° C., less than or equal to 3.5% by weight and greater than or equal to 0.3% by weight with respect to the total weight of the powdery slaked lime composition; and
characterised in that the drying/grinding steps are performed until the powdery slaked lime composition has a first fraction of particles having a size less than 32 μm and a second fraction of particles having a size greater than 32 μm, provided that the second fraction is less than or equal to 50% by weight with respect to the total weight of the powdery slaked lime composition.

2. Method according to claim 1 , characterised in that it further comprises, before, during and/or after the step of slaking the lime and/or before, during and/or after the drying and grinding steps, a step consisting of adding an additive to the quicklime, the slaking water and/or the slaked lime.

3. Method according to claim 1 , characterised in that the drying/grinding steps are performed until the powdery slaked lime composition has a mean particular size d 50 of less than or equal to 10 μm.

4. Method according to claim 1 , in which the hot air is supplied during the drying/grinding step, at a temperature between 250° C. and 500° C.

5. Method according to claim 1 , in which the drying/grinding step has a duration of between a few seconds and a few minutes.

Assignees

• Lhoist Rech Et Developpement Sa

Inventors

• Lorgouilloux Marion

Classifications

• C01F11/02 Primary

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

• C04B2/04

  Slaking {(simultaneous dehydrating of gypsum and slaking of lime C04B11/022)} · CPC title

• B01D2251/604

  Hydroxides · CPC title

• B01D2253/306

  Surface area, e.g. BET-specific surface · CPC title

• C01P2006/20

  Powder free flowing behaviour · CPC title