Calcium Hydroxide Suspension Shear Stabilization
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Solution Overview
Problem
Current aqueous lime suspensions suffer from sedimentation issues when stored without agitation, leading to handling difficulties and instability, due to poorly adapted rheology and poor deagglomeration of lime particles, which existing dispersing agents and processes fail to adequately address.
Innovation Solution
A process involving a specific shearing operation with a water-soluble comb-type copolymer having a (meth)acrylic acid skeleton and poly(alkylene glycol) side chains, applied to a concentrated aqueous suspension of calcium hydroxide, to achieve stable and concentrated suspensions with improved rheological properties, preventing sedimentation and maintaining viscosity within suitable ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional dispersing agents are used to increase dry matter content, then concentration is improved, but sedimentation and stability worsen
Solution Approach 1:
The patent applies parameter changes by modifying the rheological properties of the suspension through a specific shear treatment process. The suspension is subjected to controlled shear rates (100-10,000 s⁻¹) for specific durations, which transforms the rheological behavior from thixotropic to more stable flow characteristics, preventing sedimentation while maintaining high dry matter content (40-70%).
Solution Approach 2:
The patent implements preliminary action by applying shear treatment to the suspension before storage or use. This pre-shear process (steps c and d) modifies the particle arrangement and fluid structure in advance, ensuring that when the suspension is later stored without agitation, the particles remain suspended and do not settle, thus stabilizing the composition beforehand.
2Quantity of substance
If high dry matter content is achieved, then transport and handling costs are reduced, but viscosity increases making handling difficult
Solution Approach 1:
The patent changes the rheological parameters of the suspension through controlled shear treatment. By applying specific shear rates (100-10,000 s⁻¹) and durations, the viscosity characteristics are modified to maintain pumpability and handleability even at high dry matter contents of 40-70%, resolving the contradiction between concentration and ease of operation.
3Shape
If existing dispersing agents are used, then particle dispersion is improved, but rheological properties become unsuitable for stable storage
Solution Approach 1:
The patent replaces chemical dispersing agents with a mechanical approach - controlled shear treatment. Instead of using additional chemicals to maintain dispersion, the suspension is subjected to specific mechanical shear (100-10,000 s⁻¹) that creates a stable particle arrangement and modifies rheology, achieving both good dispersion and long-term stability without chemical additives.
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 stable aqueous suspensions with high calcium hydroxide content and adapted rheology, preventing sedimentation and maintaining viscosity below 1000 mPa.s over time, enabling efficient handling and industrial application.
Implementation Method 1
a water-soluble comb-type copolymer having a (meth)acrylic acid skeleton and poly(alkylene glycol) side chains
Implementation Method 2
a homogeneous shear of shear degree greater than 50,000 s−1 is applied to the mixture
Data Source
AI summary
The invention relates to a calcium-hydroxide-based suspension comprising an additive, and to a method for producing such a suspension. Such suspensions are especially used as chemical neutralisation agents in industrial or household methods.