Central Froth Launder in Flotation Cells

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Solution Overview

Problem

Existing froth flotation arrangements face challenges in efficiently separating mineral ore particles suspended in slurry, particularly in achieving effective froth recovery and concentrate content, especially when dealing with diluted slurry.

Innovation Solution

The proposed froth flotation arrangement and method involve a primary line comprising at least three flotation cells connected in series, with each cell receiving the underflow from the previous cell. The arrangement includes a tank with an impeller and gas supply, a froth collection launder with a froth overflow lip, and specific ratios between the available froth surface area and pulp area to optimize froth recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the available froth surface area is reduced, then the froth recovery is improved, but the froth collection efficiency deteriorates

Engineering Contradiction:
Improvefroth recoveryVSAvoidfroth collection efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent repositions the froth collection launder from a traditional peripheral location to a central location within the flotation cell. This spatial reconfiguration changes the geometry of froth transport, reducing the horizontal distance bubbles must travel and improving collection efficiency despite reduced available froth surface area.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent modifies the ratio between available froth surface area and pulp area to be less than 0.45, and controls the height-to-diameter ratio to be less than 1.5. These parameter changes optimize the balance between froth recovery and collection efficiency by creating a compact froth layer with shorter transport distances.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the horizontal transport distance of froth is reduced, then the recovery of coarse particles is improved, but the froth collection launder design becomes more complex

Engineering Contradiction:
Improverecovery of coarse particlesVSAvoidfroth collection launder design
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

By moving the launder to a central position and adjusting its orientation, the patent creates shorter horizontal transport paths for froth. This geometric transformation reduces the distance coarse particle-bubble aggregates must travel, improving recovery without requiring complex mechanical components.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs a circular tank configuration with the launder positioned centrally, creating radial symmetry in the froth collection system. This curved, radial arrangement optimizes froth flow patterns and reduces transport distances compared to linear or angular configurations.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 configuration reduces the available froth surface area, leading to improved froth recovery and concentrate content, even with diluted slurry, by minimizing the horizontal transport distance of fragile bubble particle aggregates and stabilizing the froth layer.

Implementation Method 1

introducing gas into the tank through a gas supply

Methodology Applied
Scientific EffectBubble formation: Bubble

Implementation Method 2

A froth flotation arrangement is used for treating mineral ore particles suspended in slurry

Methodology Applied
Scientific EffectFroth flotation: Froth Floatation

Implementation Method 3

mixing the slurry and the gas with an impeller within the tank

Methodology Applied
Scientific EffectMechanical mixing: Stirring

Implementation Method 4

separating the slurry in a flotation cell into an underflow and an overflow

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentEP4115982B1A froth flotation arrangement and a froth flotation method
Publication Date: 2025.04.09 METSO OUTOTEC FINLAND OY
  • EP4115982B1 patent drawingFigure 1~2
  • EP4115982B1 patent drawingFigure 3~4
  • EP4115982B1 patent drawingFigure 5~6

AI summary

The invention comprises a froth flotation arrangement and method for treating mineral ore particles suspended in slurry. The froth flotation arrangement comprising a flotation cell (1) for separating the slurry (2) into an underflow (3) and an overflow (4), wherein the arrangement comprises: a primary line (18) comprising at least three flotation cells (1) connected in series, wherein each subsequent flotation cell (1) is arranged to receive the underflow (3) from the previous flotation cell (1), the flotation cell (1) comprising a tank (5), and the flotation cell (1) comprising an impeller (7) within the tank (5), and the flotation cell (1) comprising a gas supply (8) within the tank (5), the tank (5) comprising a volume of at least 200 m3, the flotation cell (1) comprising a froth collection launder (15) capable to receive the overflow (4), the froth collection launder (15) comprising a froth overflow lip (14), the flotation cell (1) having an available froth surface area (A froth), the flotation cell having a pulp area (A pulp), where the pulp area (A pulp) is calculated as an average from the cross sectional areas of the tank (5) at the height (h1) of the impeller (7). A ratio between a height (h) from a bottom (13) of the tank (5) to the froth overflow lip (14) of the froth collection launder (15) and the diameter (D) of the tank (5) at the height (h1) of the impeller (7) (h/D ) is less than 1,5. The third flotation cell (1) or subsequent flotation cell (1) in the series has a ratio between an available froth surface area and the pulp area (A froth/A pulp) less than 0,45.