Lignosulfonate Viscosity and Air Entrainment Control
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Solution Overview
Problem
Lignosulfonates used in concrete admixtures face issues with viscosity increase, air entrainment, and set retardation, primarily due to high levels of sugars and resin/fatty acids, leading to stability and strength problems in concrete applications.
Innovation Solution
A process involving the treatment of crude lignosulfonate compositions with heat to reduce sugar levels and the use of trivalent ions to complex air-entraining fatty and resin acids, while actively cooling to prevent viscosity buildup, results in low viscosity, low air-entrainment, and reduced set retardation lignosulfonate compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If lignosulfonates are used as dispersants in concrete admixtures, then water reduction and strength improvement are achieved, but air entrainment and set retardation occur due to high sugar and resin/fatty acid content
Solution Approach 1:
The patent removes harmful components (sugars and resin/fatty acids) from the lignosulfonate composition through extraction processes. Specifically, sugars are removed via hydrolysis and filtration, while resin and fatty acids are removed through acidification and separation, thereby eliminating the causes of air entrainment and set retardation while preserving the dispersant functionality
Solution Approach 2:
The patent changes the chemical parameters of the lignosulfonate composition by controlling pH levels during processing. Acidification to pH 2-4 facilitates resin and fatty acid removal, while subsequent neutralization restores the dispersant properties. This parameter manipulation enables selective removal of harmful components without compromising the beneficial concrete strength enhancement
2Productivity
If crude lignosulfonate compositions are used immediately after evaporation, then production efficiency is maintained, but storage instability and viscosity increase occur due to microbial growth and polycondensation
Solution Approach 1:
The patent applies preliminary treatment actions to the lignosulfonate composition during the production process itself. By removing sugars (microbial food source) and resins through hydrolysis, acidification, and filtration before storage, the composition is pre-stabilized against microbial growth and polycondensation, ensuring long-term storage stability without requiring additional stabilization steps later
Solution Approach 2:
The patent converts the harmful effect of acidification (which could cause precipitation) into a beneficial separation process. By controlling pH to 2-4, resin and fatty acids are selectively precipitated and removed, while the lignosulfonate remains soluble. The harmful acidity is then neutralized, transforming the potential defect into a purification advantage
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 produces stable lignosulfonate compositions with reduced air entrainment and set retardation, enhancing concrete strength and production rates by minimizing sugar content and air content, thus overcoming the limitations of existing lignosulfonate modifications.
Implementation Method 1
applying heat to a crude lignosulfonate composition under suitable conditions to reduce sugar levels
Implementation Method 2
mixing the composition prepared by step a) with an effective amount of a source of trivalent ion to complex air entraining fatty acids and resin acids
Implementation Method 3
actively cooling the product of step b) to prevent viscosity build-up
Data Source
AI summary
A method for preparing a low-air entraining, low viscosity lignosulfonate composition. The method comprises: a) applying heat to the crude lignosulfonate composition under suitable conditions to reduce sugar levels to below 10%, optionally below 5%, optionally below 3%), or optionally below 1%, on a dry basis; b) mixing a crude lignosulfonate composition with an effective amount of a source of trivalent ion to complex air entraining fatty acids and resin acids; c) lowering temperature to prevent viscosity buildup.