Method for producing a calcium silicate hydrate-comprising hardening accelerator in powder form

Patent metadata

Field	Value
Publication number	US-10144673-B2
Application number	US-201615560552-A
Country	US
Kind code	B2
Filing date	Apr 20, 2016
Priority date	Apr 21, 2015
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

The invention relates to a method for producing a calcium silicate hydrate-comprising hardening accelerator in powder form, which comprises the steps of
(a) providing an aqueous suspension comprising calcium silicate hydrate; (b) mixing at least one calcium compound, selected from calcium acetate, calcium formate, calcium hydroxide, calcium oxide, and mixtures of two or more of said compounds, with the aqueous suspension comprising calcium silicate hydrate; and (c) drying the resulting mixture.

The invention also relates to the hardening accelerator obtainable by this method, to the use thereof, and to building material mixtures which comprise the hardening accelerator.

First claim

The invention claimed is:

1. A method for producing a calcium silicate hydrate-comprising hardening accelerator in powder form, which comprises the steps of
(a) providing an aqueous suspension comprising calcium silicate hydrate;
(b) mixing at least one calcium compound, selected from calcium acetate, calcium formate, calcium hydroxide, calcium oxide, and mixtures of two or more of said compounds, with the aqueous suspension comprising calcium silicate hydrate; and
(c) drying the resulting mixture.

2. The method according to claim 1 , wherein the suspension comprising calcium silicate hydrate is obtained by reacting an aqueous solution or suspension of a calcium source with an aqueous solution or suspension of a silicate source in the presence of at least one polymeric dispersant which comprises structural units having anionic or anionogenic groups and structural units having polyether side chains.

3. The method according to claim 1 , wherein the calcium compound is selected from calcium hydroxide, calcium oxide, and mixtures thereof.

4. The method according to claim 1 , wherein the calcium compound in an amount of 0.5 to 150 wt % based on the solids content of the calcium silicate hydrate-comprising suspension from step (a), is mixed with the calcium silicate hydrate-comprising suspension from step (a).

5. The method according to claim 1 , wherein the drying is accomplished by spray drying or roll drying.

6. The method according to claim 1 , wherein the calcium compound in an amount of 1 to 30 wt %, based on the solids content of the calcium silicate hydrate-comprising suspension from step (a), is mixed with the calcium silicate hydrate-comprising suspension from step (a).

7. The method of claim 1 comprising utilizing the calcium compound as a drying aid in the drying of the aqueous suspension comprising calcium silicate hydrate.

8. The method of claim 1 comprising utilizing the calcium compound for improving the redispersibility of the calcium silicate hydrate-comprising hardening accelerators in powder form.

9. A calcium silicate hydrate-comprising hardening accelerator in powder form, obtained by the method according to claim 1 .

10. A building material mixture which comprises the calcium silicate hydrate-comprising hardening accelerator in powder form according to claim 9 , and a hydraulic and/or latent hydraulic binder.

11. A process comprising mixing the calcium silicate hydrate-comprising hardening accelerator in powder form according to claim 9 in a building material mixture which comprises a hydraulic and/or latent hydraulic binder.

12. A process comprising mixing the calcium silicate hydrate-comprising hardening accelerator in powder form according to claim 9 as an admixture for hydraulic and/or latent hydraulic binders.

13. A method for accelerating the hardening of a building material mixture which comprises adding the calcium silicate hydrate-comprising hardening accelerator of claim 9 in powder form to the building material mixture comprising a hydraulic and/or latent hydraulic binder and allowing the obtained mixture to harden.

Assignees

• Basf Se

Inventors

• Bichler Manfred
• Winklbauer Martin
• Gaedt Torben
• Dengler Joachim
• Hesse Christoph
• Mayr Bernhard

Classifications

• C04B24/2605

  containing polyether side chains · CPC title

• C04B40/0042

  Powdery mixtures · CPC title

• C04B24/267

  containing polyether side chains · CPC title

• C04B22/064

  of the alkaline-earth metals · CPC title

• C04B14/043

  Alkaline-earth metal silicates, e.g. wollastonite · CPC title