Cemented Paste Backfill Dry Premix Rheology Control
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Solution Overview
Problem
Conventional methods for preparing cemented paste backfill materials for mining operations face challenges in achieving high mechanical strength while maintaining pumpability and flowability, often requiring complex chemical additions and specialized equipment.
Innovation Solution
A method involving a dry premix containing a hydraulic binder, a superplasticizer, and optionally a defoaming agent, which is mixed with ground mine tailings and water to create a cemented paste backfill with a solids content of 70-82 wt.%, improving rheological properties and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the solid content of the backfill material is increased to improve mechanical strength, then the mechanical properties are improved, but the rheological behaviour deteriorates and pumpability is reduced
Solution Approach 1:
The patent changes the rheological parameters of the backfill material by adding specific admixtures (viscosifiers and defoaming agents) that modify the flow characteristics. The viscosifier increases the apparent viscosity to prevent segregation while the defoaming agent removes air bubbles that would otherwise create poor flowability, thus maintaining pumpability at high solid content (70-82 wt.%)
Solution Approach 2:
The patent introduces intermediary substances (admixtures including viscosifiers and defoaming agents) that mediate between the conflicting requirements of high solid content and good pumpability. These admixtures act as intermediaries that enable the material to maintain both high mechanical strength potential and adequate flowability for gravity feeding and pumping
2Quantity of substance
If thickeners and presses are used to increase solid content, then the solid content increases to 70-82 wt.%, but the process complexity and equipment requirements increase
Solution Approach 1:
The patent extracts and eliminates the need for complex thickening and pressing equipment by using chemical admixtures that achieve high solid content through rheological modification alone. The viscosifier and defoaming agent combination allows the slurry to maintain high solid content (70-82 wt.%) without requiring mechanical thickeners or presses, thus simplifying the process
Solution Approach 2:
The patent replaces mechanical systems (thickeners and presses) with a chemical system (admixtures). Instead of using mechanical means to increase solid content, the invention uses chemical admixtures that modify the rheological properties, allowing the material to achieve high solid content through chemical rather than mechanical means
3Ease of operation
If foaming agents are added to improve pumpability, then the pumpability improves, but the mechanical strength is reduced due to air voids
Solution Approach 1:
The patent employs a two-stage sequential action: first adding the viscosifier to improve pumpability and prevent segregation, then adding the defoaming agent to remove air bubbles and improve mechanical strength. This periodic sequential addition of different admixtures allows both pumpability and strength requirements to be met
Solution Approach 2:
The patent maintains continuous useful action by combining multiple admixtures that work together synergistically. The viscosifier continues to provide pumpability improvement while the defoaming agent simultaneously addresses air voids, creating a continuous improvement of both pumpability and mechanical strength rather than trading one for the other
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 method enhances the flowability and stability of high-density cemented paste backfill, allowing for gravity feeding without pumps, while achieving improved mechanical properties and reduced air content, thus simplifying the process and reducing costs.
Implementation Method 1
a dry premix, said premix comprising the hydraulic binder, a superplasticizer and optionally a defoaming agent
Implementation Method 2
a dry premix, said premix comprising the hydraulic binder, a superplasticizer and optionally a defoaming agent
Implementation Method 3
a hydraulic binder, a superplasticizer and optionally a defoaming agent, which is mixed with ground mine tailings and water to create a cemented paste backfill
Implementation Method 4
enhances the flowability and stability of high-density cemented paste backfill, allowing for gravity feeding without pumps
Data Source
AI summary
A process of preparing a cemented paste backfill material, the material including ground mine tailings, a hydraulic binder and water, wherein the solids content of the backfill material is 70-82 wt.-%, the process including a) providing a dry premix, the premix including the hydraulic binder, a superplasticizer and optionally a defoaming agent, b) mixing the dry premix with the ground mine tailings and water.