High Solids PCC Slurry via Polymer-Modified Carbonation

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Solution Overview

Problem

Conventional processes for producing precipitated calcium carbonate (PCC) result in low solids content slurries, requiring energy-intensive and costly up-concentration steps, which can damage the PCC structure and are inefficient.

Innovation Solution

A process involving the use of a water-soluble polymer with a specific molecular weight range and a slaking additive, such as sodium citrate, to create a high solids content PCC slurry without mechanical or thermal up-concentration, maintaining the crystallographic structure and reducing viscosity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional PCC production processes are used, then PCC slurry is produced, but the solids content is low and additional up-concentration steps are required

Engineering Contradiction:

Improvesolids contentVSAvoidprocess efficiency

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent changes the chemical parameters of the slaking process by introducing specific additives (polyacrylate with molecular weight 10,000-1,000,000 and calcium chloride) to modify the precipitation kinetics and particle formation, enabling direct production of high solids content slurry without up-concentration steps

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses polyacrylate as an intermediary substance that mediates between calcium hydroxide and carbon dioxide during the carbonation process, controlling particle growth and enabling high solids content while maintaining acceptable viscosity

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If mechanical dewatering processes using centrifuges are used for up-concentration, then PCC slurry concentration is increased, but the PCC structure is destroyed

Engineering Contradiction:

Improvesolids contentVSAvoidPCC structure

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent replaces mechanical dewatering systems (centrifuges) with a chemical process approach using controlled carbonation in the presence of polyacrylate, achieving high solids content through chemical precipitation rather than mechanical force, thus preserving the PCC crystal structure

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Quantity of substance

If up-concentration steps are added to increase solids content, then PCC slurry concentration is improved, but energy consumption and costs increase

Engineering Contradiction:

Improvesolids contentVSAvoidenergy consumption

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent performs preliminary action by optimizing the slaking and carbonation process parameters from the beginning, using specific additives and controlled conditions to directly produce high solids content slurry, avoiding the need for subsequent energy-intensive up-concentration steps

Inventive Principle:

Principle #10Preliminary action

4Stability of the object's composition

If polyacrylate with high molecular weight is used, then slurry viscosity increases, but if low molecular weight is used, then PCC structure control is insufficient

Engineering Contradiction:

ImprovePCC structureVSAvoidviscosity

Core Design Contradiction:

Stability of the object's compositionVSForce

Solution Approach 1:

The patent optimizes the molecular weight parameter of polyacrylate to the specific range of 10,000-1,000,000, balancing the competing requirements of PCC structure control (which requires sufficient polymer chain length) and slurry viscosity (which increases with molecular weight)

Inventive Principle:

Principle #35Parameter changes

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 content PCC slurry with reduced viscosity, eliminating the need for additional concentration steps and preserving the PCC structure, thereby improving efficiency and product quality.

Implementation Method 1

slaking quicklime with water

Methodology Applied

Scientific EffectSlaking reaction: Chemical Bonding

Implementation Method 2

precipitating calcium carbonate by passing carbon dioxide through the resulting calcium hydroxide suspension

Methodology Applied

Scientific EffectCarbonation: Chemical Bonding

Implementation Method 3

precipitated calcium carbonate

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Data Source

PatentUS10000388B2Production of PCC

Publication Date: 2018.06.19 COATEX SA

AI summary

The present invention is directed to a process for producing an aqueous suspension of precipitated calcium carbonate, wherein a milk of lime is prepared by mixing water, a calcium oxide containing material, at least one water-soluble polymer having a molecular weight Mw in the range from 200 to 6500 g/mol, and at least one slaking additive, and subsequently, the milk of lime is carbonated to form an aqueous suspension of precipitated calcium carbonate.