Magnesium Hydroxide Slurry Stability via Acid Mediation

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Solution Overview

Problem

Magnesium hydroxide slurries face challenges with low solids concentration, high viscosity, and poor stability during shipping and storage, leading to costly transportation and potential settling issues, and existing methods like slaking magnesium oxide are exothermic and costly.

Innovation Solution

A stable magnesium hydroxide slurry composition with 50-70% solids by weight, incorporating additives such as polycarboxylate or polyether polycarboxylate, and a method involving mixing magnesium hydroxide powder with water and additives to achieve a viscosity below 1000 centipoise, ensuring stability through a 7-day pour test of 90% or greater.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If magnesium hydroxide slurry is produced with high solids concentration (50-70%), then stability and transportation efficiency are improved, but viscosity increases making pumping difficult

Engineering Contradiction:

Improvesolids concentrationVSAvoidpumping ease

Core Design Contradiction:

Quantity of substanceVSEase of operation

Solution Approach 1:

A small amount of acid (0.01-5% by weight relative to Mg(OH)2) is introduced as an intermediary substance to modify the surface properties of magnesium hydroxide particles. This acid treatment creates a slurry where high solids concentration (50-70%) is maintained while viscosity remains manageable for pumping operations, resolving the contradiction between solids content and pumpability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The chemical parameter of the slurry is changed by introducing acid to alter the surface charge and interaction between particles. This parameter change allows the system to achieve both high solids concentration and low enough viscosity for easy pumping, transforming the physical state of the slurry to simultaneously satisfy both requirements

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If magnesium hydroxide slurry contains 35-42% water by weight, then particle settling is reduced, but transportation cost increases due to large water volume

Engineering Contradiction:

Improveslurry stabilityVSAvoidtransportation cost

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The water content parameter is changed from the conventional 35-42% to a reduced level while maintaining stability through acid modification. The acid-treated slurry achieves optimal stability at lower water content, reducing the 35-42% water requirement and thereby decreasing transportation volume and cost while still preventing excessive particle settling

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If magnesium oxide is slaked to produce magnesium hydroxide slurry, then high solids concentration is achieved, but exothermic reaction causes safety and handling problems

Engineering Contradiction:

Improvesolids concentrationVSAvoidheat generation

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

Instead of the conventional approach of slaking magnesium oxide (MgO) to produce magnesium hydroxide (Mg(OH)2), the invention inverts the process by directly using magnesium hydroxide as the starting material. This eliminates the exothermic slaking reaction entirely, achieving high solids concentration without heat generation or associated safety hazards

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention converts the harmful exothermic slaking reaction into a beneficial direct-use process. By skipping the slaking step and using Mg(OH)2 directly, the process eliminates the harmful heat generation while maintaining the benefit of high solids concentration, effectively transforming a harmful process into a safe one

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 solution provides a stable magnesium hydroxide slurry with improved solids concentration, viscosity, and extended storage and shipping capabilities, reducing transportation costs and eliminating heat-related hazards, while maintaining high stability and ease of pumping.

Implementation Method 1

since magnesium hydroxide slurries are generally dispersions of magnesium hydroxide solids in water, the magnesium hydroxide particles will eventually settle in the slurry over time according to the principles of Stokes' law

Methodology Applied

Scientific EffectStokes' law: Stokes Drift

Implementation Method 2

combining magnesium hydroxide powder with water and additives to achieve a viscosity below 1000 centipoise

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentUS9890054B2Process for producing a stabilized magnesium hydroxide slurry

Publication Date: 2018.02.13 MARTIN MARIETTA MAGNESIA SPECIALTIES INC

AI summary

The present disclosure provides stable magnesium hydroxide slurry compositions and methods for producing stable magnesium hydroxide slurry compositions. The stable magnesium hydroxide slurries of the disclosure comprise magnesium hydroxide at about 50 to about 70% solids by weight in the slurry, a viscosity of less than about 1000 centipoise, and a 7-day pour test of 90% or greater.