Vaterite Calcium Carbonate Precipitation from Limestone for Low-CO2 Cement
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Solution Overview
Problem
Carbon dioxide emissions from cement production contribute significantly to global warming and ocean acidification, necessitating effective sequestration and utilization methods.
Innovation Solution
A method involving the direct dissolution of limestone in an aqueous base solution, such as ammonium chloride, to form calcium carbonate in the vaterite polymorph, which can be used to produce cementitious products without the need for lime production, thereby capturing CO2 and reducing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional cement production methods are used, then cement products are produced, but CO2 emissions are significantly high
Solution Approach 1:
The patent captures CO2 emissions from cement production and converts them into useful calcium carbonate precipitate through chemical reaction with ammonium chloride solution, transforming a harmful greenhouse gas into a valuable product that can be used as a cementitious material or for carbon sequestration
Solution Approach 2:
Instead of releasing CO2 as waste product, the patent recovers and utilizes it by dissolving limestone in ammonium chloride solution under controlled conditions to precipitate calcium carbonate, thereby recovering the carbon that would otherwise be emitted
2Object-generated harmful factors
If limestone is dissolved in aqueous base solution to form vaterite, then CO2 emissions are reduced, but process complexity increases
Solution Approach 1:
The patent employs parameter changes by controlling temperature, pressure, and chemical concentration to induce the formation of vaterite polymorph from calcium carbonate precipitation, achieving both emission reduction and product utility through controlled physical-chemical transformations
3Object-generated harmful factors
If vaterite is produced through dissolution and precipitation, then CO2 is captured, but production time increases
Solution Approach 1:
The patent performs preliminary action by pre-dissolving limestone in ammonium chloride solution to create a saturated calcium chloride solution before introducing CO2, which accelerates the subsequent precipitation reaction and reduces overall production time while maintaining effective CO2 capture
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces CO2 emissions by up to 80% compared to traditional cement production, offering operational and environmental benefits while producing stable or reactive vaterite for cementitious applications.
Implementation Method 1
dissolving limestone in an aqueous base solution under one or more dissolution conditions to produce a first aqueous solution comprising calcium salt, and a gaseous stream comprising carbon dioxide
Implementation Method 2
treating the first aqueous solution comprising calcium salt with the gaseous stream comprising carbon dioxide under one or more precipitation conditions to form a precipitation material comprising calcium carbonate
Implementation Method 3
dissolving limestone in an aqueous base solution, such as ammonium chloride, to form calcium carbonate in the vaterite polymorph
Data Source
AI summary
Provided herein are methods and systems to form calcium carbonate comprising vaterite, comprising dissolving limestone in an aqueous base solution under one or more precipitation conditions to produce a precipitation material comprising calcium carbonate and a supernatant solution, wherein the calcium carbonate comprises vaterite.