Deinking Flotation Surfactant Removal Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The de-inking process using dispersed air flotation is hindered by surfactants, which reduce the hydrophobicity of ink particles and air bubbles, leading to inefficient ink removal and selectivity, causing unwanted entrainment of valuable materials like fibers and fillers.
Innovation Solution
An additional stage of flotation by dispersed air is implemented to separate and reduce surfactants from de-inking waters, optimizing their content to enhance flotation efficiency and selectivity, using a device with a cell designed for prolonged air-water contact and surfactant regulation, and integrating this stage into specific points of the de-inking process to minimize losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If surfactants are present in de-inking water to facilitate ink release, then ink removal capability is improved, but hydrophobicity of air bubbles and ink particles is reduced, leading to decreased flotation efficiency
Solution Approach 1:
The process is divided into two distinct flotation stages: first flotation for ink removal from paper pulp, and second flotation for surfactant removal from de-inking water. This segmentation allows each stage to optimize for its specific function without interference from surfactants affecting the overall system performance.
Solution Approach 2:
The harmful surfactants are extracted from the de-inking water through a dedicated second flotation stage. Air bubbles selectively capture surfactants and carry them to the surface as foam, which is then removed. This extraction eliminates the negative effects of surfactants on hydrophobicity while preserving their beneficial ink-release function from the first stage.
2Productivity
If surfactants are added to release ink particles, then ink detachment is improved, but selectivity of flotation is reduced, causing entrainment of valuable fibers and fillers
Solution Approach 1:
The flotation process is segmented into two independent stages with different objectives. The first stage focuses on ink detachment and removal, while the second stage specifically targets surfactant removal. This segmentation allows optimal surfactant concentration for ink release to be maintained in the first stage without compromising selectivity, as the second stage corrects any selectivity issues by removing excess surfactants.
Solution Approach 2:
The second flotation stage acts as a preliminary purification step before the de-inking water is reused or discharged. By removing surfactants in advance, the system ensures that subsequent flotation operations or papermaking processes are not adversely affected by reduced selectivity, thereby maintaining manufacturing precision throughout the overall process.
3Productivity
If air bubbles are used to float ink particles, then ink removal is achieved, but surfactant adsorption at bubble interface reduces bubble hydrophobicity and particle attachment efficiency
Solution Approach 1:
The second flotation stage is specifically designed to extract surfactants from the de-inking water. Air bubbles in this stage selectively adsorb surfactants at their interfaces and transport them to the surface as foam. This extraction removes the substance causing interference, allowing the first stage to operate with maximum efficiency without surfactant degradation of bubble hydrophobicity.
Solution Approach 2:
The two flotation stages operate in continuous sequence, with the first stage performing ink removal and the second stage performing surfactant removal. This continuous action ensures that surfactants are constantly being removed from the system, maintaining optimal conditions for bubble-particle attachment throughout the process and preventing accumulation of interfering substances.
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 improves the selectivity and efficiency of ink removal, reducing surfactant interference and minimizing losses of valuable materials, thereby enhancing the overall de-inking process.
Implementation Method 1
in the presence of surfactants, these air bubbles adsorb these surfactants at their interface, thus generating bubbles that are much better stabilized in water
Implementation Method 2
the ink particles will naturally tend to adsorb at their interface. The air bubbles then carry them to the surface, usually forming a foam concentrated in ink
Implementation Method 3
The hydrophobic inks in the suspension naturally tend to float on the surface of the suspension, since they have more affinity with the outside air than with the liquid medium in which they bathe
Data Source
Figure 1A~1D
AI summary
The invention relates to a deinking process comprising at least one step of separating surfactant substances by flotation with dispersed air, as well as the deinking device adapted to the implementation of such a process.