Amphoteric Polymer Flocculation for Mining Tailings Water Recovery
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Solution Overview
Problem
Current methods for treating mining residues, such as oil sands tailings, are inefficient in separating and recycling water, leading to environmental and safety concerns due to the large volumes of semi-liquid mud stored in open basins, which can take centuries to solidify and pose a risk of dike failure.
Innovation Solution
The process involves adding a water-soluble polymer obtained by controlled radical polymerization, specifically a polymer with a UL viscosity between 2 and 4.5 cps, composed of nonionic and anionic monomers, to the mining effluent to enhance sedimentation and water separation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional settling ponds are used to store tailings, then the volume of stored sludge increases, but the sedimentation rate remains too slow and water separation efficiency is insufficient
Solution Approach 1:
The patent introduces a specific polymer as an intermediary substance to facilitate the sedimentation process. The polymer acts as a mediator between the solid particles and water, enhancing particle aggregation and settling velocity without requiring changes to the fundamental settling pond infrastructure.
Solution Approach 2:
The patent changes the chemical parameters of the suspension by adding a polymer with specific properties (amphoteric nature, particular molecular weight range, specific charge density). This alters the rheological and colloidal properties of the tailings suspension, accelerating sedimentation and improving water separation efficiency.
2Productivity
If polymer dosage is increased to improve sedimentation, then performance improves up to a point, but beyond the dosage limit performance deteriorates
Solution Approach 1:
The patent optimizes the polymer dosage parameter to a specific range (0.1-10 mg/L) where the amphoteric polymer achieves maximum effectiveness. The specific charge density and molecular weight parameters of the polymer are designed to work effectively at these low dosages, avoiding the performance deterioration that occurs with conventional polymers at higher dosages.
Solution Approach 2:
The patent uses a composite polymer structure combining both anionic and cationic functional groups in a single molecule. This amphoteric composite structure allows the polymer to interact with both negatively and positively charged particle surfaces, enhancing flocculation efficiency at lower dosages and preventing the performance collapse seen with single-charge polymers.
3Quantity of substance
If existing polymers are used for flocculation, then some water separation is achieved, but performance deteriorates beyond a certain dosage limit
Solution Approach 1:
The patent modifies the charge density parameter of the polymer to a specific range (-5 to +5 mEq/g) and optimizes the molecular weight to 10,000-1,000,000 g/mol. These parameter changes enable the polymer to maintain effectiveness across a wide dosage range (0.1-10 mg/L), eliminating the sharp performance deterioration point that characterizes conventional polymers.
Solution Approach 2:
The amphoteric polymer possesses multiple functional groups (both anionic and cationic) within a single molecule, enabling it to work effectively across varying pH conditions and with different types of mineral particles. This multi-functionality allows a single polymer dosage to achieve consistent performance regardless of slight variations in tailings composition.
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 approach significantly increases the net water release and sedimentation rate, allowing for more efficient recycling of water and reducing the volume of tailings, while avoiding the limitations of existing polymers by maintaining performance beyond traditional dosage limits.
Implementation Method 1
The process involves adding a water-soluble polymer obtained by controlled radical polymerization, specifically a polymer with a UL viscosity between 2 and 4.5 cps, composed of nonionic and anionic monomers, to the mining effluent to enhance sedimentation and water separation efficiency
Implementation Method 2
This approach significantly increases the net water release and sedimentation rate, allowing for more efficient recycling of water and reducing the volume of tailings
Data Source
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AI summary
The present invention relates to a method for treating an aqueous effluent having solid particles, comprising the addition to the effluent of at least one water-soluble polymer comprising at least one non-ionic monomer and at least one anionic monomer obtained by controlled radical polymerization, said polymer having a UL viscosity of between 2 and 4.5 cps.