Magnetic Sieve Wire Composition for Superabsorbent Purification

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Solution Overview

Problem

The existing processes for producing superabsorbents face inefficiencies in removing metallic impurities, which can negatively impact the performance properties such as centrifuge retention capacity and absorption under pressure.

Innovation Solution

A process involving the classification of superabsorbent particles using wire mesh sieves made of a specific steel composition and subsequent removal of metallic impurities using magnetic separators, with optimized throughput and temperature conditions, to improve the purity and performance of superabsorbents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional sieves are used for classifying superabsorbent particles, then classification is achieved, but metallic impurities are not effectively removed

Engineering Contradiction:
Improveremoval of metallic impuritiesVSAvoidthroughput efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent combines classification and magnetic separation functions into a single integrated system where the sieve wires themselves are made magnetic. This merging of functions allows metallic impurity removal to occur simultaneously with particle classification, eliminating the need for separate magnetic separation equipment and maintaining high throughput while improving purification effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces conventional non-magnetic sieve materials with magnetic wire mesh, substituting a purely mechanical classification system with one that incorporates magnetic properties. This substitution enables the sieve to actively attract and retain metallic impurities through magnetic forces while still performing mechanical size classification.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If magnetic separators are added to remove metallic impurities, then purity is improved, but device complexity increases

Engineering Contradiction:
Improvepurity of superabsorbent particlesVSAvoidprocess equipment complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent eliminates the need for separate magnetic separator equipment by incorporating magnetic properties directly into the sieve wires. This merging of classification and magnetic separation functions into a single component significantly reduces device complexity while maintaining effective metallic impurity removal and high particle purity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the magnetic separation function from separate equipment and integrates it directly into the sieve structure. By taking out the need for additional magnetic separator devices and embedding the magnetic functionality within the sieve wires themselves, the system achieves effective impurity removal with minimal equipment complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Manufacturing precision

If wire mesh sieves are used for classification, then particle size separation is achieved, but wire detachment and contamination occur

Engineering Contradiction:
Improveparticle size classificationVSAvoidwire detachment and metallic impurity generation
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent converts the potential harm of wire detachment into a benefit by making the sieve wires themselves magnetic. Any detached magnetic wire fragments are automatically attracted to and retained by the magnetic sieve structure, preventing them from contaminating the superabsorbent particles. This transforms what would be a source of contamination into a self-cleaning mechanism that ensures product purity.

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

This process enhances the removal of metallic impurities, leading to improved performance properties like gel bed permeability and absorption capacity, while maintaining high corrosion resistance and throughput efficiency.

Implementation Method 1

removing metallic impurities by means of one or more magnetic separators

Methodology Applied
Scientific EffectMagnetic separation: Magnetism

Implementation Method 2

classifying the superabsorbent particles by means of one or more sieves made of a wire mesh

Methodology Applied
Scientific EffectSieving: Filter (physical)

Data Source

PatentUS11535719B2Method for the production of superabsorbers
Publication Date: 2022.12.27 BASF SE

AI summary

A process for producing superabsorbents, comprising the steps of i) classifying the superabsorbent particles by means of one or more sieves and ii) removing metallic impurities by means of one or more magnetic separators, wherein classification is accomplished using sieves made of a wire mesh, the wires of the wire mesh consist of a steel composed of at least 70% by weight of iron, at least 10% by weight of chromium and less than 2.5% by weight of nickel, and the throughput of superabsorbent particles in the magnetic separator is in the range from 2.0 to 6.5 g/s per cm2 of free cross-sectional area.