Aerated composite materials, methods of production and uses thereof
The invention provides novel aerated composite materials that possess excellent physical and performance characteristics of aerated concretes, and methods of production and uses thereof. These composite materials can be readily produced from widely available, low cost raw materials by a process suitable for large-scale production with improved energy consumption, desirable carbon footprint and minimal environmental impact.
1. A process for producing an aerated composite material, comprising:
forming a wet mixture, wherein the wet mixture comprises:
water,
a particulate comprising calcium oxide or silica having a median particle size in the range from about 10 μm to about 1 mm;
a ground calcium silicate having a median particle size in the range from about 1 μm to about 100 μm, and
an aerating agent,
casting the wet mixture in a mold;
providing conditions for generation of a gaseous product from the aerating agent thereby causing volume expansion of the wet mixture; and
curing the expanded mixture at a temperature in the range from about 20° C. to about 100° C. for about 6 hour to about 60 hours under an atmosphere of water and CO 2 .
2. The process of claim 1 , wherein curing the expanded mixture is performed under a pressure ranging from ambient atmospheric pressure to about 30 psi above ambient and under a CO 2 concentration ranging from about 50% to about 99% to produce an aerated composite material.
3. The process of claim 1 , wherein forming a wet mixture comprises mixing the following ingredients in the specified order of addition:
adding water;
adding and mixing ground calcium silicate;
adding and mixing the particulate comprising calcium oxide or silica to form a uniform slurry; and
adding and mixing the aerating agent.
4. The process of claim 1 , wherein the wet mixture further comprises an additive selected from rheology modifying admixtures, pigments, retarders, and accelerators.
5. The process of claim 1 , wherein curing the expanded mixture is performed at a temperature in the range from about 20° C. to about 80° C. for about 5 hours to about 40 hours under a vapor comprising water and CO 2 and having a pressure in the range from about ambient atmospheric pressure to about 30 psi above ambient atmospheric pressure.
6. The process of claim 5 , wherein curing the expanded mixture is performed at a temperature in the range from about 30° C. to about 70° C. for about 10 hours to about 30 hours under a vapor comprising water and CO 2 and having a pressure in the range from about ambient atmospheric pressure to about 60 psi above ambient atmospheric pressure.
7. The process of claim 1 , wherein the ground calcium silicate is selected from wollastonite, pseudo-wollastonite, rankanite, belite, and alite.
8. The process of claim 1 , wherein the particulate calcium oxide is selected from lime and wollastonite.
9. The process of claim 1 , wherein the aerating agent is selected from aluminum, iron, zinc, calcium carbide in powder form.