PEG-PEO Flocculant for Oil Sands Tailings Dewatering
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Solution Overview
Problem
Current polymeric flocculants, such as acrylamides and polyethylene oxide polymers, face challenges in achieving effective consolidation and dewatering of waste mineral slurries, including oil sands tailings, due to issues like rapid hydrolysis, sensitivity to dosage, floc shear instability, and small floc structures, which hinder efficient land reclamation and environmentally friendly storage.
Innovation Solution
A method involving a mixture of low molecular mass polyethylene glycol (PEG) and high molecular mass polyethylene oxide (PEO) polymers is introduced, which is added to the aqueous suspension of particulate material to enhance flocculation and dewatering, allowing for the formation of compact, dry solid masses that can support multiple layers without collapse, thereby improving the consolidation and storage of waste materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polyethylene oxide polymers are used as flocculants, then dewatering efficiency is improved, but floc structures become too small to support multiple layers without collapse
Solution Approach 1:
The patent combines low molecular mass polyethylene glycol (PEG) and high molecular mass polyethylene oxide (PEO) polymers into a mixed flocculant system. The PEG component forms initial floc nuclei that provide structural strength, while the PEO component enhances dewatering efficiency through bridging flocculation. This merging of two polymer systems with complementary properties resolves the contradiction between dewatering efficiency and floc structure strength.
Solution Approach 2:
The invention creates a composite flocculant system using two different polymer materials (PEG and PEO) with distinct molecular mass characteristics. The PEG (low molecular mass, 1,000-35,000 g/mol) provides structural integrity while PEO (high molecular mass, >1,000,000 g/mol) provides dewatering capability. This composite approach allows the flocculant system to simultaneously achieve both strong floc structure formation and high dewatering efficiency.
2Speed
If acrylamide polymers are used as flocculants, then flocculation speed is improved, but rapid hydrolysis occurs in alkaline solutions making them impractical
Solution Approach 1:
The patent replaces long-lived but unstable acrylamide polymers with polyethylene glycol and polyethylene oxide polymers that offer comparable flocculation performance without the hydrolysis problem. While PEG and PEO are also polymers with finite lifetimes, they lack the problematic amide groups that hydrolyze rapidly in alkaline conditions, providing reliable and consistent performance in tailings treatment environments.
Solution Approach 2:
The invention changes the chemical composition parameters of the flocculant from acrylamide-based polymers to polyethylene glycol and polyethylene oxide polymers. This parameter change eliminates the vulnerable amide functional groups that undergo rapid hydrolysis in alkaline solutions, while maintaining the polymer chain structures necessary for effective flocculation. The new polymer system achieves both fast flocculation kinetics and chemical stability in alkaline tailings environments.
3Area of stationary object
If multiple layers of waste are stacked to increase storage capacity, then land use efficiency is improved, but the waste material lacks sufficient consolidation to support multiple layers without collapse
Solution Approach 1:
The patent applies flocculants to waste material before stacking to pre-consolidate the material and form strong floc structures. This preliminary treatment ensures that each layer has sufficient strength to support subsequent layers, enabling safe multi-layer stacking. The flocculation process creates a rigidified matrix within the waste material that provides the necessary structural support for vertical stacking configurations.
Solution Approach 2:
The invention creates local structural improvements within the waste material through flocculation. The polymer flocculants concentrate at particle interfaces and within the waste matrix, creating localized zones of enhanced strength and consolidation. This local quality enhancement allows specific regions of the waste stack to bear loads, enabling overall stack stability for multi-layer configurations.
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 combination of PEG and PEO polymers significantly improves the dewatering and consolidation of waste suspensions, leading to more efficient water recovery and solidification, enabling effective land reclamation and environmentally friendly storage with reduced area requirements and improved water clarity.
Implementation Method 1
allowing the suspension to flocculate
Implementation Method 2
adding to the aqueous suspension a mixture of polyethylene oxide polymers
Implementation Method 3
dewatering the suspension
Implementation Method 4
allowing it to dewater gradually through the actions of sedimentation, drainage, evaporation, and consolidation
Data Source
AI summary
The present invention relates to a method of dewatering an aqueous mineral suspension comprising introducing into the suspension a flocculating system comprising a mixture of polyethylene glycol and polyethylene oxide polymers, in particular a mixture of one or more low molecular mass polyethylene glycol with one or more high molecular mass polyethylene oxide. Said mixture of polyethylene glycol and polyethylene oxide polymers is useful for the treatment of suspensions of particulate material, especially waste mineral slurries. The invention is particularly suitable for the treatment of tailings and other waste material resulting from mineral processing, in particular, the processing of oil sands tailings.