Mineral Flotation Water Treatment Using Microbubble Cleaning
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Solution Overview
Problem
Conventional tailings treatment methods for process water in iron ore flotation result in impurities like silicates, hydrophobic particles, and residual flotation chemicals ending up in recirculated water, affecting flotation efficiency and product quality, while chemical oxidants pose environmental and operational risks.
Innovation Solution
A method involving a gravitational solid-liquid separator followed by a cleaning flotation unit using microbubbles to flocculate and separate silica-containing particles, removing them as tailings, and forming purified process water for recirculation, while utilizing residual flotation chemicals as collectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional tailings treatment methods with long resident time (20-40 days) are used, then water quality is acceptable for reuse, but extensive space requirements and high costs are incurred
Solution Approach 1:
The patent replaces the conventional mechanical gravitational sedimentation system with a flotation-based system. Instead of relying on long-term gravitational settling in large tailings dams, the invention uses flotation cells with air bubbles to separate and remove hydrophobic particles and residual chemicals from process water, achieving water purification in a compact footprint without requiring extensive storage space.
Solution Approach 2:
The invention changes the separation mechanism from gravitational settling (based on particle density and size) to flotation (based on surface hydrophobicity). By adjusting parameters such as air bubble size, agitation speed, and chemical dosing, the system achieves effective separation of fine particles and residual collectors from process water in a short residence time, eliminating the need for long-term storage.
2Area of stationary object
If thickened tailings methods with short sedimentation time (3-8 h) are used, then space requirements are reduced, but impurities like silicates and residual chemicals end up in recirculated water
Solution Approach 1:
The patent converts the harmful effect of residual hydrophobic collector chemicals and hydrophobic gangue particles into a beneficial separation mechanism. By introducing flotation, these same hydrophobic substances that caused contamination now become the basis for effective separation - the residual collectors and hydrophobic particles attach to air bubbles and are removed with the froth, leaving purified process water for recirculation.
Solution Approach 2:
The invention introduces air bubbles as an intermediary medium to facilitate separation. The bubbles act as carriers that selectively attach to hydrophobic particles and residual chemicals, transporting them to the surface for removal. This intermediary mechanism enables efficient separation of fine impurities that cannot be effectively removed by gravitational settling alone.
3Loss of time
If chemical oxidants are used to treat tailings flows, then decomposition of residual chemicals is accelerated, but environmental hazards and operational risks increase
Solution Approach 1:
The patent employs a self-service approach where the residual flotation chemicals themselves are utilized as collectors in the flotation process. Instead of adding external chemical oxidants to decompose these substances, the system allows the residual collectors to naturally perform their hydrophobicity function in the flotation cell, attaching to air bubbles and being removed with the froth. This eliminates the need for additional chemical treatment and avoids associated environmental hazards.
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 reduces silicate and chemical contamination in recirculated water, maintaining flotation process efficiency and quality, and avoids environmental hazards associated with chemical oxidants.
Implementation Method 1
a) dewatering overflow of the flotation circuit in a gravitational solid-liquid separator to separate a sediment from a supernatant
Implementation Method 2
b) 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
Data Source
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AI summary
A method for treating process water of a flotation arrangement (1) is disclosed. The process comprising the steps of a) dewatering overflow of a mineral flotation circuit (10) in a gravitational solid-liquid separator (21) to separate a sediment (212) from a supernatant (211) comprising water, silica-containing particles and soluble SiO2, fine particles, microbes, and residual flotation chemicals; b) subjecting the supernatant (211) 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 (23) for collecting at least silica-containing particles, for separating at least silica-containing particles from the supernatant into cleaning flotation overflow (232), and for forming purified process water (231) as cleaning flotation underflow; c) removing cleaning flotation overflow (232) as tailings; and d) recirculating purified process water (231) into the mineral flotation circuit (10). A process water treatment arrangement (20) is also disclosed.