Calcined Tailings Blends for Cementitious Reclamation Materials
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Solution Overview
Problem
The slow consolidation and poor water quality of fluid fine tailings (FFT) and mature fine tailings (MFT) from oil sands extraction limit reclamation options, with existing treatments like gypsum use leading to high soluble calcium concentrations impairing subsequent extraction processes, resulting in vast amounts of untreated tailings in ponds.
Innovation Solution
Calcining dewatered tailings and/or mine waste at elevated temperatures to produce a pozzolanic product, combined with additives like lime and other minerals to create a cementitious product with enhanced compressive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gypsum is used to treat FFT/MFT, then the treatment process can be implemented, but the resulting release water contains high concentrations of soluble calcium which impairs effectiveness of subsequent extraction processes
Solution Approach 1:
The patent changes the chemical parameters of tailings treatment by using calcination at elevated temperatures (900-1100°C) to transform the chemical composition of clay minerals, converting them into pozzolanic materials that react differently than gypsum treatment, thereby avoiding high soluble calcium concentrations while achieving effective treatment
Solution Approach 2:
The patent utilizes phase transition through calcination, heating tailings to high temperatures to transform clay minerals from their natural phase into a pozzolanic phase, fundamentally changing their chemical reactivity and behavior in subsequent extraction processes, thereby avoiding the harmful effects of gypsum treatment
2Productivity
If traditional CHWE process is used for bitumen extraction, then bitumen can be extracted, but tailings remain in fluid state for decades with slow consolidation and poor water quality
Solution Approach 1:
The patent applies preliminary action by treating tailings with lime before dewatering and calcination processes, preparing the material in advance to achieve rapid consolidation and cementitious strength development, thereby avoiding decades-long fluid storage required by traditional CHWE processes
Solution Approach 2:
The patent creates composite materials by combining lime-treated tailings with additional lime and other additives, forming a cementitious composite that achieves rapid consolidation and structural strength, fundamentally changing the long-term behavior from persistent fluid state to stable solid material
3Ease of manufacture
If lime is added to tailings at elevated pH levels, then the tailings can be dewatered and treated, but additional treatment is required before reclamation is possible
Solution Approach 1:
The patent merges multiple treatment functions into a single calcination step that simultaneously achieves dewatering, stabilization, and reclamation readiness by heating lime-treated tailings to high temperatures, eliminating the need for separate additional treatment steps required by conventional methods
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 produces a stable, economically valuable cementitious product that can be used in industries like concrete and soil stabilization, addressing the reclamation challenges of FFT/MFT and reducing environmental impact.
Implementation Method 1
calcining dewatered tailings and/or mine waste at elevated temperatures to produce a pozzolanic product
Implementation Method 2
calcining the processed tailings to produce calcined tailings
Implementation Method 3
produces a stable, economically valuable cementitious product that can be used in industries like concrete and soil stabilization
Implementation Method 4
combined with additives like lime and other minerals to create a cementitious product with enhanced compressive strength
Data Source
AI summary
Methods and systems for calcining dewatered tailings and/or mine waste are disclosed herein. In some embodiments, the method comprises (i) processing dewatered tailings comprising clay minerals, (ii) calcining the processed tailings to produced calcined tailings, and (iii) altering a composition and/or one or more characteristics of the calcined tailings to produce a cementitious product. Altering the composition can include blending the calcined tailings with one or more additives, such as lime, dolomitic lime, lime kiln dust, argillaceous limestone, limestone, pulverized quicklime, ground calcium carbonate, quicklime, gypsum, natural pozzolans, artificial pozzolans, water, flow aids, or the like.