Aqueous Dispersion Flow Rate via Sequential Polymer Addition
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Solution Overview
Problem
The challenge in mining operations is to enhance the flow rate of aqueous dispersions containing valuable minerals and metals while reducing the high rheological properties, such as yield stress and viscosity, which are exacerbated by the presence of gangue minerals and fine, irregularly shaped particles, leading to increased energy costs and operational difficulties.
Innovation Solution
A process involving the sequential addition of a natural polymer, preferably dextran, and a synthetic polymer to the aqueous dispersion, which reduces the yield stress without affecting sedimentation rates, thereby improving flow rates and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If synthetic polymer flocculants are used to accelerate liquid-solid separation, then sedimentation rates improve, but rheological parameters (viscosity and yield stress) increase making pumping more difficult
Solution Approach 1:
A natural polymer (dextran) is introduced as an intermediary substance between the gangue particles and the synthetic polymer flocculant. The dextran adsorbs onto the gangue particles first, creating a coating that modifies their surface properties. When the synthetic polymer is then added, it interacts with the dextran-coated particles rather than bare gangue, resulting in flocculation that achieves adequate sedimentation rates while maintaining lower yield stress and viscosity, thus facilitating easier pumping.
2Productivity
If higher dosages of synthetic polymer are used to agglomerate gangue particles, then sedimentation rates improve, but operating costs increase
Solution Approach 1:
The natural polymer dextran serves as a bridge that enhances the effectiveness of the synthetic polymer flocculant. By pre-coating the gangue particles with dextran, the synthetic polymer can achieve adequate flocculation at lower dosages compared to treating bare gangue particles. This intermediary approach reduces the total quantity of chemical polymers required while maintaining acceptable sedimentation rates.
3Productivity
If chemicals are used to coagulate or flocculate solids, then liquid-solid separation improves, but rheological properties increase making transport more challenging
Solution Approach 1:
Dextran acts as an intermediary that modifies the interaction between flocculants and gangue particles to produce flocculates with more favorable rheological properties. The dextran-coated flocs have reduced yield stress and viscosity compared to those formed by synthetic polymer alone, which directly translates to lower energy requirements for pumping and transporting the concentrated slurry through the system.
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 decreases the yield stress of the aqueous dispersion, allowing for faster transportation and processing of concentrated slurries with reduced flocculating agent usage, resulting in energy savings and cost reduction.
Implementation Method 1
This approach decreases the yield stress of the aqueous dispersion, allowing for faster transportation and processing of concentrated slurries
Implementation Method 2
adding a natural polymer to the aqueous dispersion, and then adding a synthetic polymer to the aqueous dispersion
Data Source
Figure 1~2
Figure 3
AI summary
A process for improving the flow rate of an aqueous dispersion which comprises adding a natural polymer to said aqueous system and then adding a synthetic polymer to the aqueous system.