High Solids PCC Suspension via Copolymer Additive
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Solution Overview
Problem
Conventional processes for producing precipitated calcium carbonate (PCC) often require additional energy-intensive and costly concentration steps to achieve high solids content, which can damage the PCC structure and involve complex separation processes.
Innovation Solution
A process involving a calcium oxide-containing material and a specific copolymer, where the calcium oxide and water are mixed in a certain ratio to form a milk of lime, which is then carbonated to produce a high-solids PCC suspension without the need for mechanical or thermal concentration steps, thereby maintaining the crystallographic structure and simplifying the production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional PCC production processes are used to produce high solids content PCC slurry, then solids concentration is achieved, but energy consumption increases and PCC structure is damaged
Solution Approach 1:
The invention changes the chemical composition parameters by introducing specific additives (polyacrylate with molecular weight 10,000-100,000 and/or maleinate-containing polymer with molecular weight 1,000-10,000) to modify the carbonation process. This allows achieving high solids content (40-70 wt%) without energy-intensive concentration steps, as the additives control crystal growth and suspension stability throughout the process
Solution Approach 2:
The additives are introduced before the carbonation step begins, during the preparation of calcium hydroxide suspension. This preliminary action ensures that the polymer is already present to control crystal formation and prevent aggregation from the start, eliminating the need for subsequent concentration operations that would damage the PCC structure
2Quantity of substance
If mechanical dewatering processes using centrifuges are used to concentrate PCC slurry, then solids content is increased, but PCC structure is destroyed
Solution Approach 1:
The polymer additives act as intermediary substances between calcium hydroxide and carbon dioxide during carbonation. They mediate the crystal growth process to form stable, non-aggregating PCC particles that maintain their structure at high concentrations, eliminating the need for mechanical dewatering that would otherwise destroy the crystal structure
Solution Approach 2:
By changing the chemical environment through additive introduction, the invention achieves high solids content through controlled chemistry rather than mechanical force. The polymer concentration and molecular weight parameters are optimized to ensure particles remain stable and structurally intact at 40-70 wt% solids content
3Quantity of substance
If additional solids concentration steps are added to PCC production process, then solids content is increased, but process complexity and cost increase
Solution Approach 1:
The useful action of particle formation and stabilization continues throughout the entire carbonation process without interruption. The polymer additives maintain particle stability from nucleation through growth to final high-concentration suspension, making continuous high-solids production possible without intermediate concentration steps or additional 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 achieves a high-solids PCC suspension with acceptable viscosity, eliminating the need for additional concentration steps and preserving the PCC structure, thus improving efficiency and reducing costs.
Implementation Method 1
at least one copolymer... wherein R1 represents hydrogen or a sulphonic functional group... the copolymer adsorbs onto the surface of precipitated calcium carbonate particles
Implementation Method 2
precipitating calcium carbonate by passing carbon dioxide through the resulting calcium hydroxide suspension
Implementation Method 3
R1 represents hydrogen or a sulphonic functional group... the copolymer... provides electrostatic repulsion between particles
Data Source
Figure 1
AI summary
The present invention relates to a process for producing an aqueous suspension of precipitated calcium carbonate, an aqueous suspension of precipitated calcium carbonate and a precipitated calcium carbonate obtained by the process, a product comprising the aqueous suspension of precipitated calcium carbonate or the precipitated calcium carbonate as well as its use.