Flotation Process Water Treatment Using Dissolved Gas Cleaning
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Solution Overview
Problem
Conventional methods for treating process water in flotation arrangements, particularly in Fe reverse flotation, result in impurities such as silicates, flotation chemicals, and microbiological growth, which negatively affect the quality and efficiency of the main flotation process when recirculated due to short sedimentation times and inefficient separation of fine particles.
Innovation Solution
A method involving a gravitational solid-liquid separator followed by a cleaning flotation unit, specifically a dissolved gas flotation (DAF) unit, to separate and remove silica-containing particles and other impurities from the overflow, forming purified process water that can be recirculated back into the flotation circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional tailings dam method with long resident time (20-40 days) is used, then water quality is acceptable and solids sediment effectively, but space requirements are extensive and water treatment capacity is limited
Solution Approach 1:
The patent divides the water treatment process into multiple functional units: a gravitational solid-liquid separator for initial solids removal, a dissolved gas flotation unit for fine particle separation, and a filtration unit for final purification. This segmentation allows each unit to perform its specific function efficiently, achieving high water quality in a compact footprint compared to a single large tailings dam.
Solution Approach 2:
The patent replaces the purely gravitational sedimentation mechanism (passive, time-dependent) with dissolved gas flotation (active, bubble-driven). The DAF unit introduces gas bubbles that attach to fine particles, lifting them from the water stream. This substitution enables rapid separation of fine particles without requiring extended residence times or large volumes.
2Loss of time
If thickened tailings or paste methods are used, then sedimentation time is reduced to 3-8 hours, but fine particles and residual chemicals end up in overflow, worsening water quality
Solution Approach 1:
The patent replaces gravitational sedimentation with dissolved gas flotation for fine particle removal. The DAF unit introduces gas bubbles that attach to fine particles and colloids, lifting them from the water stream. This active bubble-driven mechanism achieves rapid separation (3-8 hours) while maintaining high water quality by effectively removing fine particles that would otherwise remain in the overflow.
Solution Approach 2:
The patent changes the separation mechanism from gravity-based to gas-bubble-based, fundamentally altering how particles are removed. By controlling gas bubble size, concentration, and contact time, the system achieves rapid effective separation of fine particles and chemicals from the water, producing high-quality effluent without extended sedimentation.
3Productivity
If hydrophobic amino-based flotation chemicals are used in reverse flotation, then gangue particles are effectively separated, but residual chemicals and organic material end up in recycled process water, affecting flotation process efficiency
Solution Approach 1:
The patent extracts and removes residual flotation chemicals and organic material from the recycled water stream through the DAF unit and filtration system. The dissolved gas flotation process captures these contaminants on gas bubbles, and the filtration unit removes remaining substances, ensuring that only purified water is recirculated back to the flotation process, thereby maintaining process efficiency.
Solution Approach 2:
The patent introduces gas bubbles as an intermediary medium to capture and transport residual chemicals and organic material from the water. The bubbles act as carriers that collect contaminants through adsorption and flotation, separating them from the water stream. This intermediary mechanism enables effective removal of harmful substances without disrupting the main flotation process.
4Manufacturing precision
If dissolved gas flotation is used to remove silicates, then water quality improves, but additional chemicals and energy are required for gas generation and chemical addition
Solution Approach 1:
The patent employs the process water itself as the gas source for the DAF unit. By dissolving gases from the process water stream into the flotation cells, the system uses its own resources to drive the separation process. This self-service approach eliminates the need for external gas generation systems, reducing energy consumption while maintaining effective silicate removal and high water quality.
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
The method effectively removes impurities, reducing their impact on the main flotation process, improving the quality and efficiency of the flotation process by utilizing residual flotation chemicals for flocculation and maintaining water hardness, thus enhancing the recovery of high-quality iron materials.
Implementation Method 1
dewatering overflow of the flotation circuit in a gravitational solid-liquid separator to separate a sediment from a supernatant
Implementation Method 2
subjecting the supernatant to cleaning flotation in which at least 90% of the flotation gas bubbles display a size from 0.2 to 250 μm, in a cleaning flotation unit for collecting at least silica-containing particles
Implementation Method 3
utilizing residual flotation chemicals for flocculation
Data Source
AI summary
A method for treating process water of a flotation arrangement is disclosed. The process comprising the steps of a) dewatering overflow of a mineral flotation circuit in a gravitational solid-liquid separator to separate a sediment from a supernatant comprising water, silica-containing particles and soluble SiO2, fine particles, microbes, and residual flotation chemicals; b) subjecting the supernatant to cleaning flotation, in which at least 90% of the flotation gas bubbles have a size from 0.2 to 250 μm, in a cleaning flotation unit for collecting at least silica-containing particles, for separating at least silica-containing particles from the supernatant into cleaning flotation overflow, and for forming purified process water as cleaning flotation underflow; c) removing cleaning flotation overflow as tailings; and d) recirculating purified process water into the mineral flotation circuit. A process water treatment arrangement is also disclosed.