Synthetic Pozzolans

Patent metadata

Field	Value
Publication number	US-2017320781-A1
Application number	US-201715587705-A
Country	US
Kind code	A1
Filing date	May 5, 2017
Priority date	May 5, 2016
Publication date	Nov 9, 2017
Grant date	—

Abstract

Synthetic pozzolans are produced using local materials to provide a cementitious material that is uniform in chemistry and properties independent of the location where the materials are obtained. Two methods of production are described. One is a high temperature process in which materials are processed in a semi-molten or molten state. The second process is a low temperature aqueous process.

First claim

What is claimed is:

1 . A synthetic pozzolan comprising:
at least 10% by mass of an activatable amorphous phase comprised of one or more of siliceous, aluminosiliceous and aluminous material, said activatable amorphous phase configured to be activated by conducting a chemical reaction to form a cementitious compound.

2 . The synthetic pozzolan of claim 1 , further comprising a crystalline phase.

3 . The synthetic pozzolan of claim 2 , wherein said crystalline phase comprises in its majority crystalline melilite.

4 . The synthetic pozzolan of claim 2 , wherein said crystalline phase comprises in its majority crystalline plagioclase feldspar.

5 . The synthetic pozzolan of claim 2 , wherein said crystalline phase comprises in its majority crystalline alkali feldspar.

6 . A method of making a synthetic pozzolan, said synthetic pozzolan comprising at least 10% by mass of an activatable amorphous phase, the method comprising the step of performing a solid state reaction in a high temperature process to produce a clinker.

7 . The method of making a synthetic pozzolan of claim 6 , wherein said step of performing a solid state reaction in a high temperature process comprises the steps of:
selecting one or more precursor raw materials; analyzing the chemical compositions of said one or more precursor raw materials; blending said one or more precursor raw materials to obtain a blended precursor composition with a bulk molar ratio of Ca to the sum of Al, Fe, Mg, Si of 0.5-1.0 and a sum of metal oxides of Al, Fe and Mg of at least 14% by weight; and heating said blended precursor composition to a temperature between 800° C. and 1400° C. for a time sufficient to react said blended precursor composition to produce a melilite based clinker.

8 . The method of making a synthetic pozzolan of claim 6 , wherein said step of performing a solid state reaction in a high temperature process comprises the steps of:
selecting one or more precursor raw materials; analyzing the chemical compositions of said one or more precursor raw materials; blending said one or more precursor raw materials to obtain a blended precursor composition with a bulk chemistry of AlSi 2 O 8 with the addition of a one or more of CaAl (anorthite end member), NaSi (albite end member), or KAl (orthoclase end member) with a molar ratio of the CaAl+NaSi+KAl components to AlSi 2 O 8 of 0.8-1.2 to 1; and heating the blended precursor composition to a temperature between 800° C. and 1400° C. for a time sufficient to react said blended precursor composition to produce a plagioclase feldspar based clinker.

9 . The method of making a synthetic pozzolan of claim 6 , further comprising the step of using of a pretreatment chemical to improve a reaction rate or a maximum extent of reaction of said solid state reaction over said reaction rate or said maximum extent of reaction that is observed in the absence of said pretreatment chemical.

10 . The method of making a synthetic pozzolan of claim 9 , wherein said pretreatment chemical is an organic acid solution containing at least one of acetic acid, citric acid, tartaric acid, gluconic acid, and oxalic acid.

11 . The method of making a synthetic pozzolan of claim 6 , comprising the step of introducing said pretreatment chemical during grinding of the clinkers.

12 . The method of making a synthetic pozzolan of claim 6 , comprising the step of introducing said pretreatment chemical to a ground clinker.

13 . A method of making a synthetic pozzolan, said synthetic pozzolan comprising at least 10% by mass of an activatable amorphous phase, the method comprising the step of performing an aqueous reaction in a low temperature process.

14 . The method of making a synthetic pozzolan of claim 13 , wherein said step of performing an aqueous reaction in a low temperature process comprises using a precursor comprising a silicate mineral configured to decompose or incongruently dissolve to form an activatable amorphous phase and a precursor chemical configured to aid in the decomposition or dissolution of the precursor mineral.

15 . The method of making a synthetic pozzolan of claim 13 , further comprising the step of percolating a CO 2 containing waste gas through a reactor.

16 . The method of making a synthetic pozzolan of claim 13 , wherein said precursor chemical is an acid.

17 . The method of making a synthetic pozzolan of claim 13 , wherein said precursor chemical is derived from CO 2 gas.

18 . The method of making a synthetic pozzolan of claim 13 , wherein said precursor chemical is synthesized from CO 2 gas.

19 . The method of making a synthetic pozzolan of claim 13 , wherein said precursor mineral is selected from a naturally obtained mineral, a siliceous limestone, a clay, wollastonite, olivine, and feldspar.

20 . The method of making a synthetic pozzolan of claim 13 , wherein said precursor mineral is a manmade material selected from ordinary Portland cement, a calcium sulfoaluminate cement, a calcium aluminate cement, a carbonateable calcium silicate cement, and synthetic foundry sand.

21 . The method of making a synthetic pozzolan of claim 13 , wherein said precursor mineral is a synthetically produced pozzolan.

22 . The method of making a synthetic pozzolan of claim 13 , wherein said precursor mineral is selected from a waste material, slag and fly ash.

23 . The method of making a synthetic pozzolan of claim 13 , wherein said activatable amorphous phase comprises SiO 2 and Al 2 O 3 .

24 . A composite material produced by the blending of a synthetic pozzolan of claim 1 with an activator and water.

25 . The composite material of claim 24 wherein the activator is selected from hydraulic cement (1-70 wt %), free lime (1-20 wt %), calcium hydroxide (1-20 wt %), and alkali hydroxides (NaOH, KOH 1 to 10 wt %), individually or in combination.

Assignees

• Solidia Technologies Inc

Inventors

• Atakan Vahit
• Quinn Sean
• Sahu Sadananda
• Tas Ahmet Cuneyt

Classifications

• C04B28/006

  containing mineral polymers, e.g. geopolymers of the Davidovits type · CPC title

• C04B28/18

  containing mixtures of the silica-lime type · CPC title

• C04B14/043

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

• C01B33/26 Primary

  Aluminium-containing silicates {, i.e. silico-aluminates} · CPC title

• C04B7/345

  Hydraulic cements not provided for in one of the groups C04B7/02 - C04B7/34 · CPC title