Surface-Reacted Precipitated Calcium Carbonate for High Surface Area
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Solution Overview
Problem
Existing methods for increasing the BET specific surface area of precipitated calcium carbonate (PCC) are inadequate, as they often rely on additives during formation rather than surface-reacting already formed PCC, and fail to generate sufficient surface area when used in place of ground calcium carbonate (GCC) due to insufficient solubilized calcium ions.
Innovation Solution
A process involving the contact of PCC with H+ ions and solubilized anions in an aqueous medium, where excess solubilized calcium ions are provided to form an insoluble, partially crystalline calcium salt on the PCC surface, ensuring calcium ions originate from the PCC and promoting surface growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PCC is used instead of GCC, then availability and certain physical properties are improved, but insufficient solubilized calcium ions prevent sufficient surface area generation
Solution Approach 1:
The patent applies preliminary action by adding a soluble calcium salt before the carbonation process to ensure sufficient solubilized calcium ions are available during PCC formation. This pre-provision of calcium ions enables the subsequent surface reaction to generate adequate surface area, resolving the limitation of using PCC instead of GCC.
2Area of stationary object
If additives are used during PCC formation, then surface area can be increased, but this approach is inadequate for PCC-based materials
Solution Approach 1:
The patent uses a soluble calcium salt as an intermediary substance that mediates between the PCC formation process and the desired high surface area outcome. The calcium salt provides the necessary calcium ions that facilitate surface reaction during carbonation, enabling surface area enhancement specifically for PCC-based materials without relying on conventional additives.
3Area of stationary object
If controlled deposition of calcium salt is performed on GCC, then specific surface area is significantly increased, but this technology cannot be implemented with PCC due to lack of solubilized calcium ions
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the slurry - specifically adding a soluble calcium salt to increase the concentration of solubilized calcium ions. This parameter modification enables the PCC-based slurry to undergo surface reaction and controlled deposition similar to GCC, making the high surface area technology implementable with PCC materials.
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 process significantly increases the BET specific surface area of PCC, achieving areas at least three times greater than without excess solubilized calcium ions, making it suitable for applications like paper, plastics, and water treatment.
Implementation Method 1
contact of PCC with H3O+ ions and solubilized anions in an aqueous medium, where excess solubilized calcium ions are provided
Implementation Method 2
form an insoluble, at least partially crystalline calcium salt of said anion on said PCC surface
Implementation Method 3
an insoluble, at least partially crystalline calcium salt of said anion, which preferably extends from the surface of at least part of the PCC
Data Source
AI summary
The present invention relates to a process for the preparation of a pigment comprising a surface-reacted precipitated calcium carbonate (PCC), the process comprising the steps of a) providing at least one precipitated calcium carbonate (PCC)-comprising pigment; b) providing H 3 O + ions; c) providing at least one anion being capable of forming water-insoluble calcium salts, said anion being solubilised in an aqueous medium; d) contacting said PCC-comprising pigment, with said H 3 O + ions and with said solubilised anions in an aqueous medium to form a slurry of surface-reacted PCC-comprising pigment, wherein said surface-reacted PCC comprises an insoluble, at least partially crystalline calcium salt of said anion formed on the surface of the PCC; wherein excess solubilised calcium ions are provided during step d). The present invention further relates to a slurry of surface-reacted PCC comprising pigment obtained by this process, its use as well as the surface-reacted PCC contained in the slurry.