Dolomite Adsorbent for Heavy Metal Removal
Solution Overview
Problem
Existing dolomite-based adsorbents for heavy metal, halogen, and metalloid face challenges in achieving consistent adsorption performance due to variations in dolomite mineral composition and firing conditions, leading to inefficiencies and increased production costs, particularly when using special firing furnaces.
Innovation Solution
A dolomite-based adsorbent with a residual CaMg(CO3)2 phase content of 0.4≤x≤35.4 wt%, analyzed using the Rietveld method via powder X-ray diffraction, is developed, which includes ferrous sulfate, allowing for effective adsorption of heavy metals, halogens, and metalloids regardless of dolomite mineral composition and firing conditions, without requiring special apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dolomite is fired under specific carbon dioxide partial pressure to control decomposition, then adsorption property is improved, but facility investment and production costs increase due to requiring special firing furnaces
Solution Approach 1:
The invention changes the firing parameter from controlling carbon dioxide partial pressure (which requires special furnaces) to controlling firing temperature within 400-900°C. This parameter substitution allows achieving the desired dolomite decomposition and adsorption properties using conventional firing equipment, thereby reducing facility investment while maintaining reliability.
2Ease of manufacture
If regulations use indirect indexes like free calcium oxide and magnesium oxide content, then manufacturing is simplified, but measurement precision and quality control reliability decrease when dolomite phase amount is small
Solution Approach 1:
The invention replaces the chemical analysis method (measuring free calcium oxide and magnesium oxide content) with a physical analysis method (X-ray diffraction for measuring undecomposed carbon dioxide component). This substitution provides more reliable measurement precision for quality control while maintaining ease of manufacture through standardized testing procedures.
3Adaptability or versatility
If dolomite mineral composition varies by locality, then raw material adaptability increases, but adsorption performance consistency deteriorates
Solution Approach 1:
The invention identifies undecomposed carbon dioxide component content as the critical parameter controlling adsorption performance, replacing the traditional focus on free calcium oxide and magnesium oxide content. By controlling this parameter through standardized X-ray diffraction measurement and adjusting firing temperature accordingly, the invention achieves consistent adsorption performance across dolomite minerals from different localities with varying compositions.
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 ensures excellent adsorption properties for heavy metals, halogens, and metalloids, facilitating quality control and cost-effective production, with adsorption removal ratios of 95% or higher, applicable for contaminated soils and wastewater treatment.
Implementation Method 1
When dolomite is fired, thermal decomposition represented by the following formula is caused and thus dolomite has adsorption property of heavy metal and the like. CaMg(CO3)2→MgO+CaCO3+CO2
Implementation Method 2
dolomite has adsorption property of heavy metal and the like
Data Source
AI summary
A dolomite-based adsorbent for heavy metal, halogen and metalloid is half-fired dolomite, and a content of a residual CaMg(CO3)2 phase in the half-fired dolomite, which is analyzed using a Rietveld method by means of powder X-ray diffraction, is 0.4≤x≤35.4 (wt %), and preferably, the dolomite-based absorbent for heavy metal, halogen and metalloid further comprises ferrous sulfate.