Tailings Gel Matrix for Oil Sands Dewatering
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Solution Overview
Problem
Current tailings management processes in oil sands mining face challenges in de-watering, consolidation, and strengthening of tailings, leading to environmental concerns and inefficiencies, including the need for extensive land and time to achieve regulatory compliance, and the difficulty in processing poor quality ores which result in reduced bitumen recovery and increased greenhouse gas emissions.
Innovation Solution
A process involving the use of a gelling agent and an activator to create a gel matrix that entraps solids, followed by drying and dewatering to produce a trafficable deposit with sufficient undrained shear strength, utilizing gelling agents such as acrylamide, acrylate, and activators like acids or bases, optionally with accelerators and reinforcing agents to enhance the treatment of tailings streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional settling ponds are used for tailings management, then water clarification is achieved, but extensive land area and long settling time are required
Solution Approach 1:
The patent changes the physical-chemical parameters of the tailings stream by adjusting pH (adding acid or base) and adding chemical agents (polyelectrolytes, coagulants) to accelerate the settling process. This transforms the slow gravitational settling into a rapid chemical precipitation process, achieving water clarification in minutes rather than years, and reducing land area requirements from hundreds of hectares to a small treatment facility footprint.
2Reliability
If traditional settling ponds are used for tailings management, then water clarification is achieved, but extensive settling time is required
Solution Approach 1:
The patent changes the physical-chemical parameters of the tailings stream by adjusting pH (adding acid or base) and adding chemical agents (polyelectrolytes, coagulants) to accelerate the settling process. This transforms the slow gravitational settling into a rapid chemical precipitation process, achieving water clarification in minutes rather than years, and reducing land area requirements from hundreds of hectares to a small treatment facility footprint.
3Productivity
If chemical thickening is used to produce thickened tailings, then water recovery is accelerated, but heat energy requirements increase
Solution Approach 1:
The patent replaces the thermal/chemical thickening process with a mechanical filtration system. Instead of using heat and chemicals to thicken tailings for water recovery, the system uses a filter press with filter media to mechanically separate water from solids. This substitution eliminates the need for heat energy input while maintaining high water recovery speed, and additionally produces a drier solid product suitable for land application.
4Reliability
If MFT ponds are used for tailings storage, then environmental containment is achieved, but environmental contamination risks remain
Solution Approach 1:
The patent extracts the harmful fine solids and water from the tailings stream through rapid chemical precipitation and mechanical filtration. By removing these components quickly and producing a stable, drier solid product, the system eliminates the need for long-term MFT ponds that pose contamination risks. The treated solid can be safely land-applied or disposed of, eliminating the ongoing environmental hazard of pond containment failure.
5Adaptability or versatility
If poor quality ores are processed, then bitumen extraction is attempted, but bitumen recovery is reduced
Solution Approach 1:
The patent changes the chemical parameters of the tailings stream by adjusting pH and adding specific chemical agents tailored to the ore composition. For poor quality ores with high clay content or fine particles, the system optimizes coagulant and polyelectrolyte selection and dosage to achieve effective separation. This allows the processing of diverse ore types while maintaining efficient bitumen recovery and producing treatable tailings for water recovery and solid disposal.
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 process effectively reduces the volume and environmental impact of tailings, enables quicker compliance with regulatory requirements, and improves bitumen recovery by producing a stable, trafficable surface that can reuse water and minimize land requirements, while also addressing the challenges posed by poor quality ores.
Implementation Method 1
contacting (1) a gelling agent and (2) an activator with said tailings stream to produce a gel matrix comprising entrapped solids
Implementation Method 2
drying and/or dewatering the gel to strengthen and solidify the gel
Data Source
AI summary
A process for treating a tailings stream comprises (a) contacting (1) a gelling agent and (2) an activator with said tailings stream to produce a gel; (b)entrapping solids including sand and clay, and other solid particles with the gel; and (c) allowing the gel to strengthen and solidify to produce a trafficable deposit; wherein the tailings stream comprises water and solids, which solids comprise sand, clay and other solids particles, and wherein 5% by volume to 100% by volume of the solids have a particle size less than 0.05 mm, based on the total volume of the solids. The process may further comprises spreading the gel produced in step (a) or the trafficable deposit produced in step (c) over a surface. The present invention is particularly useful to treat tailings streams produced in processes to extract bitumen from oil sands ores.