Mineral additives and production of lightweight composite materials from carbonatable calcium silicate

Patent metadata

Field	Value
Publication number	US-2021017081-A1
Application number	US-201815933011-A
Country	US
Kind code	A1
Filing date	Mar 22, 2018
Priority date	Mar 23, 2017
Publication date	Jan 21, 2021
Grant date	—

Abstract

The invention provides novel aerated composite materials made from a carbonatable calcium silicate composition, and formulations and methods of manufacture and use thereof, in particular, the use of novel additive mineral compositions in the form of magnesium, magnesium salts or magnesium oxides, to improve physical chemical properties of low density concrete materials. The low density, aerated material is comprised of calcium carbonate (CaCO 3 ) and silica (SiO 2 ), as cured products of carbonatable calcium silicate compositions.

First claim

1 . A process of production of an aerated composite material, comprising:
forming a wet mixture or slurry, wherein the wet mixture or slurry comprises water,
filler particles comprising CaO having a particle size of 0.1 μm to 1000 μm,
ground calcium silicate particles,
one or more minerals comprising magnesium, magnesium salt and/or magnesium oxide, and
an aerating agent,
wherein, the wet mixture or slurry has a water/solid ratio (W/S) of 1.0 or less;
casting the wet mixture or slurry in a mold; allowing the aerating agent to generate hydrogen gas thereby causing volume expansion of the slurry; pre-curing the obtained expanded mixture to a hardness enabling it to be taken out of the mold and moved; curing the pre-cured expanded mixture at ordinary pressure, 30° C. or more of temperature, a relative humidity of 1% or more, and an atmosphere of a CO 2 gas concentration of 10 to 95% for 6 hours to 60 hours.

2 . The process according to claim 1 , wherein the mold in which the wet mixture or slurry is cast is of the final dimension of a desired product shape.

3 . The process according to claim 1 , wherein the obtained pre-cured expanded mixture is cut into a desired product shape prior to curing.

4 . The process according to claim 3 , wherein the cutting of the pre-cured expanded mixture is carried out using a piano wire, diamond wire, or cutting saw.

5 . The process according to claim 1 , wherein magnesium, magnesium salt or magnesium oxide in the one or more minerals accounts for about 0.02% to about 20% by weight of the ground calcium silicate particles.

6 . The process according to claim 1 , wherein magnesium oxide in the one or more minerals accounts for about 1% to about 20% by weight of the ground calcium silicate particles.

7 . The process according to claim 1 , wherein the ground calcium silicate particles comprise one or more of a group of calcium silicate phases selected from CS (wollastonite or pseudowollastonite), C3S2 (rankinite), C2S (belite, larnite, bredigite), an amorphous calcium silicate phase, each of which material optionally comprises one or more metal ions or oxides, or blends thereof.

8 . The process according to claim 1 , wherein in the ground calcium silicate particles elemental Ca and elemental Si are present in a molar ratio from about 0.5 to about 1.5 and metal oxides of Al, Fe and Mg are present in the composition at about 30% or less by mass.

9 . The process according to claim 1 , wherein the temperature at the carbonation step is in a range from about 30° C. to about 90° C.

10 . The process according to claim 9 , wherein the temperature at the carbonation step is in a range from about 60° C. to about 85° C.

11 . The process according to claim 1 , wherein the relative humidity at the carbonation step is 10% or more.

12 . The process according to claim 1 , wherein the time at the carbonation step is 6 hours or more.

13 . The process according to claim 1 , wherein the one or more minerals further comprise one or more of magnesium, magnesium nitrate, magnesium sulphate, magnesium chloride, and magnesium acetate.

14 . The process according to claim 1 , wherein the cured low density, aerated product contains the phases of aragonite and/or dolomite together with calcite.

15 . The process according to claim 14 , wherein the one or more minerals further comprise magnesium acetate.

16 . The process according to claim 1 , wherein the slurry further comprises a dispersant or superplasticizer.

17 . The process according to claim 16 , wherein the dispersant or superplasticizer comprises a polycarboxylate-based polymer.

18 . An aerated concrete product produced by a process according to claim 1 .

19 . The aerated concrete product according to claim 18 , selected from blocks, lintels, panels and masonry units.

20 . An aerated concrete product comprising one or more of aragonite (CaCO 3 ), Mg-calcite (magnesian), magnesite (MgCO 3 ), dolomite (CaMg(CO 3 ) 2 ), hydromagnesite (Mg 5 (CO 3 ) 4 (OH) 2 .4H 2 O), nesquehonite (Mg(HCO 3 )(OH).2H 2 O or MgCO 3 .3H 2 O), dypingite (Mg 5 (CO 3 ) 4 (OH) 2 .5H 2 O), artinite (Mg 2 CO 3 (OH) 2 .3H 2 O), barringtonite (MgCO 3 .2H 2 O), and lansfordite (MgCO 3 .5H 2 O).

Assignees

• Solidia Technologies Inc

Inventors

• Tas Ahmet Cuneyt

Classifications

• Y02W30/91

  Use of waste materials as fillers for mortars or concrete · CPC title

• C04B38/0058

  open porosity · CPC title

• C04B28/188

  the Ca-silicates being present in the starting mixture · CPC title

• B28B1/503

  Moulds therefor · CPC title

• B28B11/245

  Curing concrete articles (B28B11/242 takes precedence) · CPC title