Flotation Cell Pressurized Blast Tubes Fine Particle Recovery

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Solution Overview

Problem

Traditional flotation cells face challenges in recovering fine and ultrafine particles due to large bubble sizes and turbulence, leading to reduced recovery rates and increased use of frothers, which can destabilize the process and affect particle size distribution recovery.

Innovation Solution

The use of a flotation cell with pressurized blast tubes that create smaller, ultra-fine bubbles and optimize frother usage, allowing for improved bubble-particle interaction and reduced turbulence, enhancing the recovery of fine and coarse particles without compromising bubble formation or froth stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional mechanical agitation is used to introduce flotation gas, then the flotation cell can operate with simple structure, but the generated bubbles are relatively large (0.8 to 2.0 mm) and cause turbulence that reduces recovery of fine particles

Engineering Contradiction:
Improverecovery of fine particlesVSAvoidturbulence and large bubble size
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional mechanical agitation system with a pressurized gas injection system. Gas is introduced under pressure (3-10 bar) through nozzles or spargers, creating fine bubbles (0.3-1.5 mm) without mechanical turbulence. This substitution eliminates the harmful turbulence while maintaining effective gas-liquid mixing for fine particle flotation.

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

Solution Approach 2:

The patent changes the pressure parameter of the flotation gas from atmospheric to pressurized (3-10 bar). This pressure increase forces gas through narrow nozzles or spargers, creating much finer bubbles that are more effective for fine particle recovery. The pressure parameter transformation directly addresses the bubble size issue without introducing mechanical turbulence.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If more frother is added to stabilize the process and improve froth formation, then froth stability improves, but fine and ultrafine particles are lost in the tailings due to excessive turbulence and large bubble sizes

Engineering Contradiction:
Improvefroth stabilityVSAvoidrecovery of fine and ultrafine particles
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the physical state and size parameters of the bubbles by introducing pressurized gas through restricted nozzles or spargers. This creates fine bubbles (0.3-1.5 mm) that provide sufficient surface area for fine particle attachment while minimizing turbulence. The fine bubble regime maintains froth stability without requiring excessive frother addition.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces mechanical agitation with pressurized gas injection, eliminating the turbulence that causes fine particle loss. The gas injection system creates gentle, controlled bubble rise that maintains froth stability while preventing the harmful turbulence associated with mechanical agitators.

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

3Productivity

If the flotation tank volume is increased to improve particle residence time and recovery, then more particles can be processed, but the device complexity and operational challenges increase

Engineering Contradiction:
Improveparticle recovery efficiencyVSAvoidflotation cell structure and operation
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical agitation systems with simple pressurized gas injection through nozzles or spargers. This substitution simplifies the overall cell structure while maintaining effective mixing and bubble generation. The system requires no moving parts, reducing mechanical complexity and operational challenges.

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

Solution Approach 2:

The patent uses pneumatic principles to introduce pressurized gas (3-10 bar) through nozzles or spargers for bubble generation and mixing. This pneumatic system replaces complex mechanical components with simpler pressure-driven gas injection, reducing device complexity while maintaining effective particle-bubble interaction.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 increases the recovery of valuable material by creating a thicker froth layer and improving the distribution of bubbles, leading to higher bubble surface area and efficient entrapment of particles across various sizes, while minimizing frother dosage and process water recirculation issues.

Implementation Method 1

an elongated chamber arranged to receive under pressure the slurry infeed; and an outlet nozzle configured to restrict flow of slurry infeed from the outlet nozzle, and to maintain slurry infeed in the elongated chamber under pressure

Methodology Applied
Scientific EffectPressure reduction: Depressurisation

Implementation Method 2

the blast tubes are disposed at a position relative to the bottom structure so as to induce mixing at the mixing zone

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 3

the attachment of particles to bubbles occurs in the sparger unit

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3829773B1Flotation cell
Publication Date: 2024.11.06 METSO OUTOTEC FINLAND OY
  • EP3829773B1 patent drawingFigure 1
  • EP3829773B1 patent drawingFigure 2
  • EP3829773B1 patent drawingFigure 3

AI summary

A flotation cell (1) is disclosed for treating particles suspended in slurry and for separating the slurry into an underflow (400) and an overflow (500). The flotation cell comprises a flotation tank (10) with a centre (11), a perimeter (12), a substantially horizontal level bottom (13), and a side wall (14); a launder (2) and a launder lip (21) surrounding the perimeter (12) of the tank (11); and a bottom structure (7) arranged on the bottom (13), and having a shape that allows particles suspended in slurry to be mixed in a mixing zone (A) over the bottom structure, and to settle down in a settling zone (B) surrounding the bottom structure. The flotation tank further comprises blast tubes (4) for introducing slurry infeed (100) into the tank. In addition, a flotation line and use of the flotation line are disclosed.