Surface-Reacted Calcium Carbonate Process for Controlled Porosity
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Solution Overview
Problem
There is a need for an economic method to prepare high surface area materials of surface-reacted calcium carbonate, allowing for modification of its specific BET surface area and porosity for specific applications.
Innovation Solution
A process involving treating a calcium carbonate-comprising material with phosphoric acid, carbon dioxide, and specific dicarboxylic acids in an aqueous medium, while adding a water-soluble inorganic magnesium salt before, during, or after the treatment, to form a surface-reacted calcium carbonate with controlled surface area and porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If calcium carbonate is treated with fatty acid or sodium salt of fatty acid to enhance affinity and prevent aggregation, then the surface properties are improved, but the specific BET surface area and porosity cannot be controlled for specific applications
Solution Approach 1:
The patent applies parameter changes by treating calcium carbonate with phosphoric acid and carbon dioxide to modify surface chemistry, and by controlling treatment conditions (temperature, concentration, time) to achieve desired specific BET surface area (20-200 m2/g) and porosity values, thus enabling adaptability for different applications while maintaining reliability through surface reaction
Solution Approach 2:
The patent creates composite surface structures on calcium carbonate by forming calcium phosphate layers through reaction with phosphoric acid and CO2, resulting in a composite material that combines the base calcium carbonate properties with surface-modified characteristics including controlled porosity and specific surface area, achieving both reliability and versatility
2Reliability
If conventional acid treatment methods are used to modify calcium carbonate surface, then surface reactivity is improved, but the process is not economical and does not allow predetermined modification of surface area
Solution Approach 1:
The patent employs self-service by utilizing carbon dioxide that is formed in situ during the phosphoric acid treatment process to participate in the surface modification reactions, eliminating the need for separate CO2 supply equipment and reducing process complexity, thereby improving economic feasibility while achieving reliable surface reactivity modification
Solution Approach 2:
The patent achieves economical manufacturing by conducting treatment in an aqueous medium at controlled temperature and pH conditions, using readily available phosphoric acid and allowing in situ CO2 formation, simplifying the process while enabling predetermined control of surface area and porosity parameters for reliable surface reactivity
3Area of stationary object
If high surface area materials are produced through extensive processing, then specific BET surface area is increased, but the process complexity and cost increase
Solution Approach 1:
The patent reduces process complexity by utilizing in situ formation of carbon dioxide during phosphoric acid treatment to automatically participate in surface modification reactions, eliminating the need for separate CO2 generation or supply systems, thereby achieving high surface area modification without increased device complexity
Solution Approach 2:
The patent merges multiple functions into a single treatment process: phosphoric acid treatment for surface reactivity, in situ CO2 generation for carbonate formation, and aqueous medium for dissolution and precipitation control, all occurring simultaneously to achieve high specific BET surface area without requiring multiple separate processing steps or complex equipment
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
The process enables the production of surface-reacted calcium carbonate with a specific surface area of 20-200 m2/g and controlled porosity, suitable for various applications, while avoiding microbial contamination.
Implementation Method 1
treating the calcium carbonate-comprising material with phosphoric acid, carbon dioxide, and specific dicarboxylic acids in an aqueous medium
Implementation Method 2
treating the calcium carbonate-comprising material with phosphoric acid, carbon dioxide, and specific dicarboxylic acids in an aqueous medium
Implementation Method 3
adding a water-soluble inorganic magnesium salt before, during, or after the treatment
Data Source
AI summary
The present invention relates to a process for producing a surface-reacted calcium carbonate, wherein a calcium carbonate-comprising material is treated with at least one inorganic acid and carbon dioxide in an aqueous medium to form an aqueous suspension of surface-reacted calcium carbonate, wherein the at least one water-soluble, inorganic magnesium salt is added before, during and/or after the treatment step. Furthermore, the present invention relates to a surface-reacted calcium carbonate obtained from said process and its use.