Calcium Hydroxide Slurry Stability via Polymer Mediator

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Solution Overview

Problem

Current aqueous slurries of calcium hydroxide face issues with sedimentation when stored without agitation, leading to difficulties in pumping and handling, due to poorly adapted rheology and bad disagglomeration of lime particles, which existing dispersants and processes fail to adequately address.

Innovation Solution

A process involving a specific shearing operation under controlled conditions with a polymer having a particular structure, comprising methacrylic acid monomers and poly(alkylene glycol) side chains, is used to create a stable and concentrated aqueous slurry of calcium hydroxide with a dry content of at least 40% by weight, achieving improved rheological properties and preventing sedimentation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If existing dispersants are used to increase dry solids content, then transport and handling costs are reduced, but sedimentation occurs when stored without agitation

Engineering Contradiction:
Improvedry solids contentVSAvoidsedimentation resistance
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

A specific polymer acts as an intermediary substance between water and calcium hydroxide particles. This polymer, with particular structural characteristics, mediates the interaction to create a stable dispersed system that prevents sedimentation while enabling high dry solids content (at least 40% by weight).

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the rheological parameters of the slurry by introducing a polymer with specific structural characteristics. This modifies the flow and stability properties of the slurry, enabling it to maintain homogeneity without agitation while containing at least 40% dry solids content.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If dry solids content is increased to reduce transport costs, then economic efficiency improves, but rheological properties become poorly adapted leading to handling difficulties

Engineering Contradiction:
Improvedry solids contentVSAvoidhandling ease
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The polymer addition changes the rheological parameters of the concentrated slurry, maintaining fluidity and pumpability even at high dry solids content (≥40%). This enables economic transport and handling without sacrificing operational ease.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The polymer serves as a mediator that allows high concentrations of calcium hydroxide to remain in a handleable, pumpable state. It modifies the interfacial properties between solid particles and liquid medium, preventing aggregation and maintaining flow characteristics suitable for industrial handling.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If lime particles are not properly disagglomerated, then preparation process is simpler, but sedimentation and stability issues occur

Engineering Contradiction:
Improvepreparation simplicityVSAvoidslurry stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The polymer acts as a disagglomerating intermediary that separates aggregated lime particles during mixing. Its specific structural characteristics enable it to penetrate and break apart particle aggregates, creating a stable dispersed system without requiring complex multi-step preparation processes.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 results in a stable aqueous slurry with viscosity between 25 and 1,000 mPa·s, maintaining stability over time and facilitating handling and industrial applications by preventing sedimentation and optimizing rheological properties.

Implementation Method 1

A process involving a specific shearing operation under controlled conditions with a polymer having a particular structure, comprising methacrylic acid monomers and poly(alkylene glycol) side chains, is used to create a stable and concentrated aqueous slurry of calcium hydroxide

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

maintaining stability over time and facilitating handling and industrial applications by preventing sedimentation and optimizing rheological properties

Methodology Applied
Scientific EffectSteric stabilization:

Implementation Method 3

A process involving a specific shearing operation under controlled conditions with a polymer having a particular structure

Methodology Applied
Scientific EffectShear stress: Shear Stress

Implementation Method 4

achieving improved rheological properties and preventing sedimentation

Methodology Applied
Scientific EffectRheology modification:

Data Source

PatentUS10456742B2Aqueous lime slurry, preparation process and uses
Publication Date: 2019.10.29 COATEX SA

AI summary

Preparation of aqueous slurries of calcium dihydroxide. Preparation of aqueous suspensions of calcium hydroxide.