Recycled Pulp Fiber Recovery from Used Absorbent Articles
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Solution Overview
Problem
Existing methods for recycling pulp fibers from used absorbent articles require large amounts of water, leading to water supply issues in regions with limited resources and increased treatment challenges due to high viscosity of recovered aqueous solutions containing organic matter.
Innovation Solution
A method involving a separation step to isolate inactivating aqueous solutions from used absorbent articles, a viscosity reduction step using oxidizing agents to decompose excrement, and a resupply step to reuse the treated solutions, reducing water usage and maintaining solution effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If large amounts of water are used for the aqueous solution in the decomposition step, then the used sanitary product can be effectively stirred and decomposed, but water consumption becomes extremely high and treatment of drained water becomes difficult
Solution Approach 1:
The patent changes the chemical parameters of the aqueous solution by adding specific chemicals (such as calcium chloride, aluminum sulfate, or organic acids) to modify the decomposition efficiency. This allows effective decomposition with reduced water amounts by enhancing the chemical reactivity of the solution rather than relying on large water volumes alone.
Solution Approach 2:
The patent introduces chemical intermediaries (divalent metal ions or organic acids) that mediate the decomposition process between the used sanitary product and water. These intermediaries facilitate the decomposition reaction, enabling effective treatment with lower water consumption by acting as a catalyst or reaction mediator.
2Quantity of substance
If the aqueous solution is reused after recovery, then water consumption can be reduced, but the viscosity of the recovered aqueous solution becomes high due to contained organic matter, making effective stirring and reaction difficult
Solution Approach 1:
The patent implements a continuous circulation system where the aqueous solution is repeatedly used across multiple decomposition cycles. By maintaining continuous operation and periodically regenerating the solution, the system achieves water consumption reduction while sustaining decomposition effectiveness through ongoing useful action rather than discrete batch treatments.
Solution Approach 2:
The patent applies parameter changes to the recovered aqueous solution by adjusting its chemical composition (adding fresh chemicals, adjusting pH, or supplementing oxidizing agents) to restore its decomposition capability. This allows the solution to be reused multiple times while maintaining effective stirring and reaction conditions despite the presence of organic matter.
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 approach allows for the reuse of aqueous solutions, significantly reducing water consumption and facilitating the recycling of pulp fibers while maintaining solution effectiveness, thus addressing water supply and treatment challenges.
Implementation Method 1
a viscosity reduction step of mixing a first oxidizing agent capable of decomposing the excrement and the separated inactivating aqueous solution, and decomposing the excrement that is contained in the inactivating aqueous solution to reduce a viscosity of the inactivating aqueous solution
Data Source
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AI summary
Provided is a method which is for producing a recycled pulp fiber from a used absorbent article and by which an aqueous solution recovered in a production step can be reused and the amount of water used as the aqueous solution can be reduced. Said method includes: a separating step (S10) for respectively separating an inactivating aqueous solution containing excrement and a pulp fiber from a mixed liquid obtained by mixing an inactivating aqueous solution capable of inactivating a highly water-absorbent polymer with a used absorbent article; a viscosity-reducing step (S22) for mixing a first oxidizing agent capable of decomposing excrement with the separated inactivating aqueous solution to decompose the excrement contained in the inactivating aqueous solution and reduce the viscosity of the inactivating aqueous solution; and a re-supplying step (S24) for returning, to the separating step, the inactivating aqueous solution containing a decomposition product formed by decomposing the excrement.