Magnetic Separator Coating for Polymer Impurity Removal

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Solution Overview

Problem

Existing processes for producing water-absorbing polymer particles face challenges in selectively removing metallic impurities while minimizing product damage and maintaining mechanical stability, as magnetic separation introduces abrasion and can worsen product properties.

Innovation Solution

A process involving the polymerization of a monomer solution with ethylenically unsaturated monomers, crosslinkers, and optional water-soluble polymers, where metallic impurities are removed using a magnetic separator with controlled temperature and moisture content, and the magnetic separator's surface is coated with a polymeric material to prevent caking, along with the use of an eddy current detector for ferritic and nonferritic impurities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If magnetic separation is used to remove metallic impurities, then impurity removal is achieved, but product abrasion increases and mechanical stability deteriorates

Engineering Contradiction:
Improveimpurity removalVSAvoidmechanical stability
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent applies parameter changes by controlling the temperature of the product mass flow to 35-90°C during magnetic separation. This temperature parameter optimization reduces the abrasion of polymer particles while maintaining effective magnetic separation of metallic impurities, thereby resolving the contradiction between impurity removal and mechanical stability.

Inventive Principle:
Principle #35Parameter changes

2Strength

If magnetic separator operates at high temperature, then abrasion is reduced, but magnetic field strength weakens

Engineering Contradiction:
Improvemechanical stabilityVSAvoidmagnetic field strength
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent defines an optimal temperature range of 35-90°C for the magnetic separation process. This parameter optimization balances two opposing effects: reducing particle abrasion through elevated temperature while maintaining sufficient magnetic field strength for effective impurity separation, thus resolving the contradiction between mechanical stability and magnetic field effectiveness.

Inventive Principle:
Principle #35Parameter changes

3Strength

If moisture content is increased to reduce abrasion, then mechanical stability improves, but caking tendency increases

Engineering Contradiction:
Improvemechanical stabilityVSAvoidcaking
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent optimizes the moisture content parameter of the product mass flow during magnetic separation. By maintaining appropriate moisture levels, the process reduces particle abrasion and improves mechanical stability while preventing excessive caking, thus resolving the contradiction between mechanical stability and caking tendency.

Inventive Principle:
Principle #35Parameter changes

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 mechanical stability of water-absorbing polymer particles, improves the selective separation of impurities, and maintains product quality by reducing abrasion and caking, while ensuring effective removal of metallic impurities.

Implementation Method 1

metallic impurities being removed from a product mass flow comprising water-absorbing polymer particles by means of a magnetic separator

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

the magnetic separator's surface is coated with a polymeric material to prevent caking

Methodology Applied
Scientific EffectCoating: Coatings

Implementation Method 3

the use of an eddy current detector for ferritic and nonferritic impurities

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Data Source

PatentUS8534465B2Method for removing metallic impurities
Publication Date: 2013.09.17 BASF SE

AI summary

A process for removing metallic impurities from a product mass flow comprising water-absorbing polymer particles, wherein the product mass flow has a temperature of 35 to 90° C.