Low Molecular Weight Anionic Polymer for Mature Fine Tailings Dewatering
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Solution Overview
Problem
Mature fine tailings from oil sands mining operations pose significant environmental challenges due to large storage needs and toxicity, with existing chemical flocculants like polyacrylamide increasing viscosity and negatively impacting settling rates.
Innovation Solution
Introducing an anionic organic polymer with a molecular weight of 30,000-50,000 daltons, specifically acrylic acid or acrylamide grafted onto a triblock copolymer such as Pluronic™ F-127, which interacts with tailings to enhance flocculation and dewatering without increasing viscosity, allowing for improved settling rates and rigidification of the suspension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If commercial polymers such as polyacrylamide are used to promote separation of suspended solids, then flocculation is enhanced, but viscosity increases significantly and settling rates decrease
Solution Approach 1:
The patent changes the molecular weight parameter of the polymer flocculent from high (commercial polyacrylamide) to low (30,000-50,000 daltons), and changes the chemical structure parameter by using anionic organic polymers with specific grafting patterns. These parameter changes enable effective flocculation without the viscosity increase that plagues high molecular weight polymers, thereby maintaining settling rates.
Solution Approach 2:
The patent employs composite polymer structures where acrylic acid or acrylamide is grafted onto a triblock copolymer backbone (polypropylene glycol flanked by polyethylene glycol blocks). This composite structure combines the flocculation effectiveness of polymer chains with the viscosity-control benefits of the triblock architecture, achieving both good separation and maintained settling rates.
2Reliability
If high molecular weight polymers are used to increase flocculation, then solid separation is improved, but the suspension viscosity increases
Solution Approach 1:
The patent fundamentally changes the molecular weight parameter from high (commercial standards) to low (30,000-50,000 daltons), and modifies the chemical structure by introducing anionic organic polymers with specific functional groups. These parameter changes decouple the relationship between polymer concentration and viscosity while maintaining flocculation effectiveness.
Solution Approach 2:
The patent applies local quality by concentrating the flocculation functionality in specific regions of the polymer structure (the grafted acrylic acid or acrylamide groups) while the triblock copolymer backbone provides the structural framework that controls viscosity. This localized functional distribution allows effective separation without global viscosity increase.
3Volume of stationary object
If polymer flocculents are introduced to reduce tailings storage volume, then dewatering is enhanced, but the complexity of polymer selection and dosing increases
Solution Approach 1:
By standardizing on a specific molecular weight range (30,000-50,000 daltons) and defined chemical structure (anionic organic polymers with specific grafting), the patent simplifies the polymer selection process. This parameter standardization makes dosing more predictable and reduces the complexity of selecting the right polymer for different tailings conditions.
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 described polymer flocculents demonstrate improved settling rates and efficient dewatering of mature fine tailings, reducing storage needs and environmental impact by forming a networked structure that releases more water, outperforming commercial flocculants like Magnafloc 1011.
Implementation Method 1
contacting a low molecular weight anionic organic polymer with a tailings stream to flocculate mature fine tailings and enhance dewatering
Implementation Method 2
efficient dewatering of mature fine tailings, reducing storage needs and environmental impact by forming a networked structure that releases more water
Data Source
AI summary
A process for drying mature fine tailings is provided. A low molecular weight anionic organic polymer is contacted with a tailings stream to flocculate mature fine tailings and enhance dewatering. The tailings stream can contain, for example, water, sand, silt and fines clays produced from a bitumen extraction process for oil sands ore. The process can also involve rigidification of the suspension.