Postponed Onset of Quicklime Hydration

Patent metadata

Field	Value
Publication number	US-2019010087-A1
Application number	US-201615776519-A
Country	US
Kind code	A1
Filing date	Nov 14, 2016
Priority date	Nov 16, 2015
Publication date	Jan 10, 2019
Grant date	—

Abstract

The present invention provides compositions and methods relative to controlling hydration onset of an alkaline earth metal oxide such as calcium oxide, comprising heating an inorganic alkaline earth metal oxide to sub-calcination temperatures in the presence of organic material comprising a carbohydrate, an amino-carboxylic acid, a hydroxycarboxylic acid, or a mixture thereof. Preferred treated particles comprise at least 40% and more preferably at least 80% by dry weight calcium oxide which is heated in the presence of ascorbic acid and a starch. Treated particles of the present invention manifest an unexpected, surprising hydration induction postponement behavior as demonstrated through calorimetric testing.

First claim

It is claimed:

1 . A composition comprising: treated alkaline earth metal oxide particles treated by heating precursor alkaline earth metal oxide particles comprising 40-100 percent by total dry weight of calcium oxide, magnesium oxide, or mixture thereof, at an average temperature within 200° C.-700° C., for a period of 20-300 minutes, in the presence of an organic material comprising a carbohydrate, amino-carboxylic acid, hydroxycarboxylic acid, or mixture thereof.

2 . The composition of claim 1 wherein the treated alkaline earth metal oxide particles comprise at least 50 percent by total dry weight of calcium oxide based on total dry weight of the inorganic portion of particles; and the treated particles are treated by heating to 250° C.-500° C. for 20-200 minutes.

3 . The composition of claim 1 wherein the treated alkaline earth metal oxide particles comprise at least 80-100 percent by total dry weight of calcium oxide based on total dry weight of the inorganic portion of the particles; and the treated particles were treated by heating to 250° C.-500° C. for 20-200 minutes.

4 . The composition of claim 1 wherein the treated alkaline earth metal oxide particles, after completion of heating, have delayed onset of hydration of at least 30 minutes when the particles are mixed with water, compared to otherwise identical alkaline earth metal oxide particles which have not been subjected to heating in said temperature range.

5 . The composition of claim 1 wherein the precursor particles are heated in the presence of carbohydrate, and the carbohydrate is a starch.

6 . The composition of claim 1 wherein the precursor particles are heated in the presence of an amino-carboxylic acid selected from the group consisting of aspartic acid, glutamic acid, glycine, alanine, phenylalanine, methionine, serine, and threonine.

7 . The composition of claim 6 wherein the precursor particles are heated in the presence of aspartic acid.

8 . The composition of claim 7 wherein at least 80 percent by weight of the aspartic acid is L-aspartic acid.

9 . The composition of claim 1 wherein the precursor particles are heated in the presence of a hydroxycarboxylic acid.

10 . The composition of claim 9 wherein the hydroxycarboxylic acid is citric acid.

11 . The composition of claim 1 wherein the precursor particles are heated in the presence of aspartic acid and starch.

12 . The composition of claim 1 wherein the starch is a pregelatinized starch selected from a refined starch obtained from corn, tapioca, wheat, rice, potato, sweet potato, sago, beans, and mixtures thereof.

13 . The composition of claim 1 further comprising a hydratable cementitious binder.

14 . The composition of claim 13 further comprising an aggregate.

15 . The composition of claim 14 wherein the composition, when mixed with water, forms a paste or slurry of cementitious mortar, concrete, or shotcrete.

16 . A method for modifying a cementitious composition comprising: mixing together a cementitious binder and composition according to claim 1 .

17 . The method of claim 16 wherein the cementitious binder and the composition of claim 1 are mixed together as dry powder.

18 . The method of claim 15 wherein the powder is mixed into a cementitious slurry comprising the cementitious binder and water, and then pumped through a hose to a location where the cementitious composition is placed and hardened into place.

19 . Method for treating alkaline earth metal oxide particles, comprising: heating precursor particles comprising calcium oxide, magnesium oxide, or mixture thereof in an amount of at least 40-100 percent by total dry weight based on the inorganic portion of the particles, at an average temperature within 200° C.-700° C. for a period of 20-300 minutes, in the presence of organic material comprising a carbohydrate, an amino-carboxylic acid, a hydroxycarboxylic acid, or a mixture thereof.

20 . A composition comprising: treated alkaline earth metal oxide particles treated by heating precursor alkaline earth metal oxide particles comprising calcium oxide, magnesium oxide, or mixture thereof in the amount of 70-100 percent by dry weight based on the total inorganic portion of the particles, at an average temperature within 250° C.-500° C., for a period of 20-200 minutes, in the presence of an organic material comprising aspartic acid and a starch.

Assignees

• Gcp Applied Tech Inc

Inventors

• Chun Byong-Wa

Classifications

• C04B2111/00146

  Sprayable or pumpable mixtures · CPC title

• C04B2/104 Primary

  Ingredients added before or during the burning process · CPC title

• C04B28/02

  containing hydraulic cements other than calcium sulfates · CPC title

• C04B22/064

  of the alkaline-earth metals · CPC title

• C01F5/02

  Magnesia · CPC title