Process to make calcium oxide or ordinary portland cement from calcium bearing rocks and minerals

a technology of calcium oxide and portland cement, which is applied in the field can solve the problems of inefficiency, drawbacks, and considerable challenges of the art of producing cement materials, including ordinary portland cement, and achieve the effect of less energy intensiv

Pending Publication Date: 2021-03-11
CALIFORNIA INST OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0003]Provided herein are methods for producing cement materials that have any combination of the following advantages or features: less energy intensive than prior approaches, with some embodiments being net energy neutral or even net energy producing, regenerate certain reagents, characterized by a net reaction free of SO2 and / or CO2, recycle certain byproducts, do not include producing CO2, can utilize a wider range of feedstock materials, including more complex materials, generate value-added side products, and / or generate composite cement materials.
[0004]Included herein are methods for producing cement materials using a two-acid approach, where materials are reacted with two different acids and / or two different acid reaction steps. Advantages of these approaches include all or a majority of the above mentioned advantages and features. For example, the disclosed two-acid approach provides for the ability to digest complex calcium-bearing materials, including those with Ca as well as other metal (including metalloid) elements such Si, Al, and other species, and even forming value-added side products from those non-Ca metals, while also regenerating reagent acids. Significantly, these methods can also be free of CO2 generation and can include converting SO2 into a reagent acid, thereby eliminating or dramatically reducing SO2 emissions for CaSO4 based approaches to cement manufacturing.

Problems solved by technology

The art of producing cement materials, including Ordinary Portland Cement, faces considerable challenges, inefficiencies, and / or drawbacks.
For example, conventional processes for producing cement are energy intensive, produce environment-degrading byproducts such as CO2 and / or SO2, and utilize only a limited range of feedstocks, primarily simple calcium-based materials such as calcium carbonate (limestone) or mined calcium sulfate (gypsum).

Method used

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  • Process to make calcium oxide or ordinary portland cement from calcium bearing rocks and minerals
  • Process to make calcium oxide or ordinary portland cement from calcium bearing rocks and minerals
  • Process to make calcium oxide or ordinary portland cement from calcium bearing rocks and minerals

Examples

Experimental program
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Effect test

example 1

to Make Calcium Oxide or Ordinary Portland Cement from Calcium Bearing Rocks and Minerals

[0058]Conventional cement is made by thermally decomposing CaCO3 into CaO and then mixing it with other materials including Al2Si2O5(OH)4, Fe2O3, and CaSO4. Thermal decomposition occurs at ˜900C and final OPC production occurs at ˜1450C. Most of the energy required and CO2 emissions for cement making come from the thermal decomposition of limestone:

CaCO3→CaO+CO2ΔH=178(non spontaneous)  (FX5).

[0059]Conventional cement requires 2.7-6 GJ / tonne OPC and produces 0.7-1.3 tonne CO2 per tonne of OPC (Ordinary Portland Cement). The normal cement process emits a lot of CO2 and take a lot of energy.

[0060]Included in this discloses is a process to produce CaO from any calcium-bearing rock or mineral. In nature, acid (e.g. H2CO3 or H2SO4) weathers calcium bearing minerals to produce, typically, CaCO3 or CaSO4. The general weathering trend follows:

H2CO3+CaAl2Si2O8+H2O→CaCO3+Al2Si2O5(OH)4  (FX6);

or

H2SO4+CaAl2S...

example 2

Thermal Decomposition of Limestone to Make Lime or Cement

[0065]Lime is used directly as a commodity chemical as well as the primary constituent of cement which is the most consumed human made material on the planet. Lime is currently produced via the thermal decomposition of limestone in an air atmosphere (FX16).

CaCO3→CO2+CaO  (FX16);

This heat of decomposition of this reaction is 178 kJ / mol

[0066]Included in this invention is a process to produce cement from limestone via reductive thermal decomposition with hydrogen. The first step in the process may follow the following reactions:

CaCO3+4H2→CH4+2H2O (FX17A);

or

CaCO3+2H2→CH4+O2(FX17B);

[0067]Water content of the reacting gas influences whether the reaction proceeds according to FX17A, FX17B, or both. CaCO3 can react with H2 to either make CaO+CH4+O2 or CaO+CH4+2H2O. If H2O is formed, 4H2s are consumed. If O2 is formed, only 2H2s are consumed. This reaction can be driven to only consume 2H2s if there is a water atmosphere, for example.

[...

example 3

n of Gypsum and Cement Materials

[0072]Exemplary aspect 1: The production of ordinary portland cement (OPC) from any calcium containing starting material without the net production of acid-forming gases (e.g. SO2 and CO2). Examples of calcium containing starting materials include: basalt, igneous appetites, wollastonite, slag, fly ash, anorthosite, montmorillonite, bentonite, calcium-containing feldspar, anorthite, diopside, pyroxene, pyroxenite, mafurite, kamafurite, clinopyroxene, colemonite, grossular, augite, pigeonite, margarite, calcium serpentine, garnet, scheilite, OPC, concrete, any rock that has any Ca or CaO by mass especially rocks with >5%, >10%, or >15% CaO, any skarns, limestone, gypsum, appetite, or fluorapatite.

[0073]In certain embodiments, we do this by first producing >90% pure synthetic gypsum from the above calcium containing rocks (details in claim 2) and then thermally decomposing this gypsum to make CaO and then mixing it with the proper ratios of other materi...

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Abstract

Aspects of the invention include a method of producing a cement material comprising step of: first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt; second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and thermally treating the second calcium salt to produce a first cement material. Preferably, but not necessarily, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of and priority to U.S. Provisional Application No. 62 / 886,137, filed Aug. 13, 2019, U.S. Provisional Application No. 62 / 913,620, filed Oct. 10, 2019, U.S. Provisional Application No. 62 / 932,200, filed Nov. 7, 2019, and U.S. Provisional Application No. 63 / 019,916, filed May 4, 2020, each of which is hereby incorporated by reference in its entirety to the extent not inconsistent herewith.BACKGROUND OF INVENTION[0002]The art of producing cement materials, including Ordinary Portland Cement, faces considerable challenges, inefficiencies, and / or drawbacks. For example, conventional processes for producing cement are energy intensive, produce environment-degrading byproducts such as CO2 and / or SO2, and utilize only a limited range of feedstocks, primarily simple calcium-based materials such as calcium carbonate (limestone) or mined calcium sulfate (gypsum). This application addresses these and other challeng...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C04B11/00C04B22/06C04B40/00C04B28/04C04B11/30
CPCC04B11/005C04B22/064C07C1/328C04B28/04C04B11/30C04B40/0046C04B7/36C04B7/38C04B7/24C04B7/26C04B7/147C04B7/422C04B7/424C01B17/74C25B1/22C25C1/06C04B2/10C04B2/005C04B7/04C04B7/246C04B28/14Y02P40/40C01F7/56Y02P40/10C04B14/06C04B14/303C01G49/14
Inventor FINKE, CODY E.LEANDRI, HUGO F.
Owner CALIFORNIA INST OF TECH
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