Hydrated Cement Paste Sorbent for Heavy Metal Removal
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Solution Overview
Problem
Existing methods for removing heavy metals, especially mercury, from industrial off-gases comprising CO2 are inefficient, as they require disposal of loaded sorbents in landfills and do not effectively prevent metal embrittlement and corrosive attacks on CO2 processing equipment.
Innovation Solution
A method involving the use of at least partially hydrated cement paste as a sorbent in a scrubber to capture heavy metals from off-gases, where the cement paste is simultaneously carbonated and loaded with heavy metals, and subsequently used as supplementary cementitious material in composite cements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If activated carbon or other solid sorbents are used to remove heavy metals from off-gas, then heavy metal removal efficiency is improved, but the loaded sorbent becomes difficult to reuse and requires landfilling
Solution Approach 1:
The invention changes the chemical state of the sorbent by carbonating the spent sorbent, transforming it from a waste material requiring landfilling into a valuable calcium carbonate-rich product that can be reused as a filler or flux in industrial applications
Solution Approach 2:
Instead of discarding the heavy metal-loaded sorbent to landfill, the invention recovers value by carbonating the sorbent to produce calcium carbonate, which can then be utilized in construction materials, steelmaking, or other industrial processes
2Object-affected harmful factors
If conventional sorbents are used to capture heavy metals, then mercury removal is achieved, but the process does not prevent metal embrittlement and corrosive attacks on CO2 processing equipment
Solution Approach 1:
The invention implements a continuous carbonation process that converts the spent sorbent into a stable calcium carbonate product, ensuring continuous protection against heavy metals throughout the CO2 capture process while maintaining equipment reliability
Solution Approach 2:
The invention converts the harmful heavy metal-loaded spent sorbent into a beneficial calcium carbonate product through carbonation, transforming waste into a valuable material that can be reused in construction or industrial processes
3Object-affected harmful factors
If activated carbon is used to adsorb heavy metals, then removal efficiency is improved, but the disposal of loaded material becomes a problem requiring landfilling
Solution Approach 1:
The invention changes the chemical composition and properties of the spent sorbent through carbonation, converting it from a hazardous waste requiring landfilling into a useful calcium carbonate product with industrial applications
Solution Approach 2:
The invention transforms the harmful waste material (heavy metal-loaded activated carbon) into a beneficial product (calcium carbonate) that can be reused in construction materials, steelmaking flux, or other industrial processes, eliminating the need for landfilling
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 method effectively removes heavy metals from off-gases, preventing adverse effects on CO2 processing equipment, and provides a valuable supplementary cementitious material that avoids the need for sorbent regeneration or landfilling.
Implementation Method 1
Mercury and other impurities are adsorbed into the specific surface area and the structure of micropores, contributing to their removal from the gas stream.
Implementation Method 2
the at least partially hydrated cement paste is simultaneously carbonated and loaded with the mercury and/or other heavy metals during contacting with the off-gas
Data Source
AI summary
Carbon capture method for an industrial plant off-gas involves removing mercury and/or other heavy metals from the off-gas by contacting the off-gas with an at least partially hydrated cement paste as sorbent in a scrubber before a concentration step of the off-gas to concentrate CO2. The at least partially hydrated cement paste is simultaneously carbonated and loaded with the mercury and/or other heavy metals during contacting with the off-gas and is used as supplementary cementitious material in composite cement. The at least partially hydrated cement paste is used as sorbent in a scrubber before a concentration step of the off-gas to concentrate CO2.