Two-Stage Flotation Apparatus for Fine Particle Recovery
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Solution Overview
Problem
Conventional flotation apparatuses with stirrers require high energy input to achieve sufficient kinetic energy for forming adducts with fine particles, leading to inefficient separation and necessitating additional processing steps to recover fine fractions.
Innovation Solution
A two-stage flotation process within a single apparatus, utilizing a first mixing device in the charge line to create small gas bubbles and a second mixing device with a stirrer and sparging device to form larger adducts, allowing for spatially separated turbulence zones to recover a wider range of particle sizes without excessive energy expenditure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high energy input is provided to the stirrer to achieve sufficient kinetic energy for forming adducts with fine particles, then the recovery of fine particles is improved, but the energy consumption increases significantly making the process uneconomic
Solution Approach 1:
The flotation process is divided into two distinct stages with different mixing intensities: a first stage with high-energy mixing for fine particle flotation, and a second stage with low-energy mixing for coarse particle flotation. This segmentation allows each stage to be optimized for its specific particle size range, recovering fine particles effectively without requiring the entire process to consume high energy.
Solution Approach 2:
The apparatus uses adjustable stirrer speed to dynamically control the mixing energy input. The stirrer can operate at different rotational speeds depending on the flotation stage and particle size being processed, allowing optimization of kinetic energy input to match the specific requirements of each flotation stage rather than continuously operating at high energy levels.
2Use of energy by moving object
If the stirrer operates with lower energy input to reduce costs, then energy consumption is reduced, but the kinetic energy becomes insufficient for forming adducts with fine particles
Solution Approach 1:
The flotation chamber is divided into a first flotation chamber for fine particles and a second flotation chamber for coarse particles. The first chamber receives high-energy mixing from the charge line ejector to facilitate fine particle flotation, while the second chamber uses lower-energy stirrer action for coarse particles, allowing low overall energy input while maintaining fine particle recovery.
Solution Approach 2:
The charge line with ejector performs preliminary gas dispersion and intense mixing of the pulp before it enters the flotation chamber. This preliminary high-energy action prepares the pulp for fine particle flotation without requiring the stirrer to continuously operate at high energy levels throughout the entire process.
3Device complexity
If a single flotation chamber is used with a stirrer, then the device complexity is low, but additional downstream flotation apparatus are required to recover fine fractions from residual pulp
Solution Approach 1:
A single flotation chamber is segmented into two distinct flotation zones: a first flotation chamber for fine particles and a second flotation chamber for coarse particles. This internal segmentation allows one apparatus to perform the function of multiple separate flotation units, recovering both fine and coarse fractions in a single pass without requiring additional downstream equipment.
Solution Approach 2:
The second flotation chamber is positioned within or alongside the first flotation chamber, with the stirrer extending into both zones. This nested arrangement allows one flotation system to handle multiple particle size ranges simultaneously, eliminating the need for separate flotation apparatus for coarse particle recovery.
4Productivity
If the charge line leads into the flotation chamber above the stirrer, then spatial separation of turbulence zones is achieved, but the device complexity increases
Solution Approach 1:
The charge line is positioned to lead into the flotation chamber at a specific location above the stirrer, creating a localized high-energy turbulence zone in the first flotation chamber. This localized positioning allows intense mixing and fine particle flotation to occur in a specific region without requiring complex overall apparatus design, maintaining simplicity while achieving effective particle size separation.
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 enables higher yields by effectively converting a broader range of particle sizes into foam products, reducing the need for subsequent flotation steps and optimizing the recovery of fine fractions.
Implementation Method 1
For the purpose of dispersing a gas in the pulp a first mixing device is present in the charge line
Implementation Method 2
a second mixing device comprising a stirrer and a sparging device associated with the stirrer is present inside the flotation chamber
Implementation Method 3
The gas bubbles present in the pulp adhere to the hydrophobic particles, thereby producing adducts, also called aeroflocs
Implementation Method 4
flotation chemicals for hydrophobizing the surface of the valuable particles
Implementation Method 5
In order to enable aeroflocs to form it is necessary to induce turbulences in the pulp with the aid of a mixing device, the aforementioned stirrer
Data Source
AI summary
A flotation apparatus may include a flotation chamber having a side wall and a base, a stirrer, a sparging device associated with the stirrer, a first foam-collecting device arranged in an upper region of the flotation chamber for the purpose of collecting a foam product formed during the flotation process, and a charge line for charging the flotation chamber with pulp, wherein the charge line leads into the flotation chamber at a point above the stirrer and an ejector is present in the charge line. Further, a flotation method is performed in two stages inside a flotation chamber of a flotation apparatus, wherein an ejector is used in a first flotation stage and a stirrer is used in a second flotation stage.