CA2981529A1

CA2981529A1 - Automated alnalyzer and methods for analysis of tailings samples subjected to flocculation

Info

Publication number: CA2981529A1
Application number: CA2981529A
Authority: CA
Inventors: Adrian Revington; Benito Moyls; Kushagra Mittal
Original assignee: Suncor Energy Inc
Current assignee: Suncor Energy Inc
Priority date: 2017-09-29
Filing date: 2017-10-05
Publication date: 2019-03-29
Also published as: CA2980902A1

Description

I
AUTOMATED ANALYZER AND METHODS FOR ANALYSIS OF TAILINGS SAMPLES
SUBJECTED TO FLOCCULATION
TECHNICAL FIELD
[0001] The technical field generally relates to the analysis of tailings, such as thick fine tailings or mature fine tailings (MET), subjected to flocculation, and more particularly to the testing and characterization of the flocculation of tailings in the context of dewatering operations.
BACKGROUND

[0002] Tailings derived from mining operations, such as oil sands mining, are often placed in dedicated disposal ponds for settling. Different types of tailings have different compositions and can include coarse solids, fine solids, and other components.

[0003] The settling of fine solids from the water in tailings ponds is a relatively slow process. Certain techniques have been developed for dewatering thick fine tailings, such as oil sands mature fine tailings (MFT). Dewatering of thick fine tailings can include retrieving the tailings from the pond, contacting the tailings with a flocculant to form a flocculated fine tailings material and then depositing the flocculated fine tailings material in a deposition area where the deposited material can release water and eventually dry.

[0004] Various aspects can be taken into consideration when designing a tailings treatment operation to optimize dewatering. Analysis of a tailings sample to test and characterize properties of the sample, properties of a flocculant added to the sample, and properties of the flocculation process can be a useful tool to design or improve the tailings treatment operation.
SUMMARY

[0005] The automated flocculation sample analyzer and analysis methods described herein facilitate reliable testing of tailings samples, particularly to assess the impacts of mixing characteristics and other variables on flocculation and dewatering performance.
For example, the automated flocculation sample analyzer can be used to test multiple tailings samples at different conditions (e.g., mixing characteristics, flocculant type, flocculant dosage, flocculant feed rate, tailing properties, pre-treatments, and so on), where the evolution of the sample's flocculation is monitored by tracking torque for example, and the flocculation characteristics of the sample can then be correlated with certain input variables. The automated flocculation sample analyzer and analysis methods described herein are particularly useful for bench-scale assessment of impacts of mixing scales¨including micro-mixing, meso-mixing, and macro-mixing¨which can in turn facilitate enhancements in the design or operation of a larger-scale flocculation and dewatering process.

[0006] Various implementations and aspects to provide an automated flocculation sample analyzer, analysis methods, and other methods for treating tailings, are described and illustrated herein and recited in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a process flow diagram showing a thick fine tailings dewatering operation.

[0008] Figures 2a to 2c are schematic graphs showing example reaction stages for flocculated thick fine tailings, such as oil sands MFT, for example flocculation and dewatering processes.

[0009] Figure 3 is a graph showing a relationship between the speed and torque exerted by a motor as a function of time, for a MET sample.

[0010] Figure 4 is an example of an algorithm that can be used to assess the contribution of mixing scales to the flocculation performance.

[0011] Figure 5 is a schematic representation of an automated flocculation sample analyzer according to an implementation.

[0012] Figure 6 is a front perspective view of an automated flocculation sample analyzer according to an implementation.

[0013] Figure 7 is a rear perspective view of the automated flocculation sample analyzer shown in Figure 6.

[0014] Figure 8 is a side plan view of the automated flocculation sample analyzer shown in Figure 6.

[0015] Figure 9 is a side perspective view of a mixing vessel of an automated flocculation sample analyzer according to an implementation.

[0016] Figure 10 is a plan side view of the mixing vessel shown in Figure 9.

[0017] Figure 11 is a side perspective view of an automated flocculation sample analyzer according to another implementation.

[0018] Figure 12 is a graph showing the relationship between the clay based dose and the 24h clay-to-water ratio (CWR) for two automated flocculation sample analyzers, one having a 4" diameter mixing vessel and another having a 6" diameter mixing vessel.

[0019] Figure 13 is a graph showing the relationship between impeller speed and NWR for tests with an automated flocculation sample analyzer.

[0020] Figure 14 is a graph showing the relationship between Clay Based Dose (g/tonne) and 24hr CWR for two automated flocculation sample analyzers, one having standard injection features and another having features for improved meso-mixing.

[0021] Figure 15 is a graph showing the relationship between polymer dosage (g/tonne clays) and 24hr CWR for different mixing speeds.

[0022] Figure 16 is a graph showing the relationship between polymer dosage (g/tonne clays) and 24hr CWR for different mixing speeds and a 5"x1" impeller slotted or not.

[0023] Figure 17 is a graph showing the relationship between polymer dosage (g/tonne clays) and 24hr CWR for different mixing speeds and a 4.5"x1.5"
impeller slotted or not.

[0024] Figures 18A and 18B are schematic representations of a flocculant injection and mixing system, i.e. a pipeline, that includes an in-line injector.

DETAILED DESCRIPTION

[0025] Dewatering operations for treating tailings, such as thick or thin fine tailings, can include subjecting the thick fine tailings to a flocculation process followed by pipeline conditioning and dewatering, which may include deposition of the flocculated fine tailings material onto a sub-aerial deposition site or supplying the flocculated fine tailings material to a mechanical dewatering unit. In order to enhance flocculation and dewatering of the fine tailings, an automated flocculation sample analyzer can be used to assess and characterize properties of the flocculation process based on different variables, such as the tailings sample, the type and dosage of flocculant, and mixing parameters.

[0026] More regarding the automated flocculation sample analyzer, associated methods, systems and applications, as well as various flocculation and dewatering implementations, will be discussed below. The following paragraphs provides certain definitions of terms used herein.

[0027] It is noted that various different types of tailings can be analyzed using the techniques described herein. The tailings can come from different sources, ore bodies, and processing plants. The tailings can also have different properties in terms of composition, such as fines content, solids content, clay-to-water ratio (CWR), and so on.
For example, in some implementations, the automate analyzer can be used to test tailings samples of thick fine tailings, thin fine tailings, or other types of tailings that can be generated by a mining and extraction operation. The techniques described herein are particularly useful for assessing fine tailings, which are tailings that have a notable fines content on a total solids basis and thus haver a lower concentration of coarse solids.
The fine tailings can be thick fine tailings or thin fine tailings, for example.

[0028] As referred herein, "thick fine tailings" can be considered as suspensions derived from a mining operation and mainly include water and fines. The fines are small solid particulates having various sizes up to about 44 microns. The thick fine tailings have a solids content with a fines portion sufficiently high such that the fines tend to remain in suspension in the water and the material has slow consolidation rates. More particularly, the thick fine tailings can have a ratio of coarse particles to the fines that is less than or equal to 1. The thick fine tailings have a fines content sufficiently high such that flocculation of the fines and conditioning of the flocculating material can achieve a two-phase material where release water can flow through and away from the flocs. For example, thick fine tailings can have a solids content between 10 wt% and 45 wt%, and a fines content of at least 50 wt% on a total solids basis, giving the material a relatively low sand or coarse solids content. The thick fine tailings can be retrieved from a tailings pond, for example, and can include what is commonly referred to as "mature fine tailings" (MFT).

[0029] "Thin fine tailings" can generally be considered as a tailings material that has a solids content below about 10 wt%, and a relatively high fines content (e.g., at least 50 wt% on a total solids basis). Thin fine tailings are typically formed when "whole tailings"
or "extraction tailings" which include coarse and fine solids are allowed to settle or otherwise separate such that the coarse solids predominantly drop out of the tailings and thus the remaining fluid tailings have a certain concentration of suspended fine solids, which is often in the range of about 8 wt%. Thin fine tailings tend to eventually form MFT
when allowed to settle further. Thin fine tailings can be the result of taking whole tailings and running them through a sand dump to remove coarse sand and thereby produce thin fine tailings. The thin fine tailings can be supplied to a pond to form MFT or can be directly treated.

[0030] "MFT" refers to a tailings fluid that typically forms as a layer in a tailings pond and contains water and an elevated content of fine solids that display relatively slow settling rates. For example, when whole tailings (which include coarse solid material, fine solids, and water) or thin fine tailings (which include a relatively low content of fine solids and a high water content) are supplied to a tailings pond, the tailings separate by gravity into different layers over time. The bottom layer is predominantly coarse material, such as sand, and the top layer is predominantly water. The middle layer is relatively sand depleted, but still has a fair amount of fine solids suspended in the aqueous phase. This middle layer is often referred to as MFT. MFT can be formed from various different types of mine tailings that are derived from the processing of different types of mined ore.
While the formation of MFT typically takes a fair amount of time (e.g., between 1 and 3 years under gravity settling conditions in the pond) when derived from certain whole tailings supplied form an extraction operation, it should be noted that MFT
and MFT-like materials can be formed more rapidly depending on the composition and post-extraction processing of the tailings, which can include thickening or other separation steps that can remove a certain amount of coarse solids and/or water prior to supplying the processed tailings to the tailings pond.

[0031] While several aspects and implementations of the automated analyzer, methods, and overall dewatering operations will be described in the context of thick fine tailings, it should be noted that the techniques described herein can also be used on or adapted for thin fine tailings or other types of tailings.
General overview of flocculation and dewatering operations

[0032] An overview of an exemplified thick fine tailings dewatering operation 100 is described in general terms and with reference to Figure 1. In some implementations, the dewatering operation 100 includes providing thick fine tailings from a tailings source 102, which can be a tailings pond for example, from which a flow of tailings 104 is retrieved by a retrieval assembly 105, which can include dredge or another type of pumping arrangement. The tailings 104 can then be subjected to pre-treatments, such as screening and/or pre-shearing in one or more pre-treatment units 106, for producing a pre-treated tailings flow 108 that is then supplied to a chemical addition unit 110 for contacting and mixing with a dewatering chemical (e.g., a flocculant 113) from a dewatering chemical supply 112. It is noted that one or more dewatering chemical additives can be added to the thick fine tailings at one or more injection points along the pipeline. Once the thick fine tailings 104 are mixed with the flocculant 113, a flocculation tailings material 114 can be pipelined through a transportation and conditioning assembly 116 and then to a dewatering unit 118. The dewatering unit 118 can be a sub-aerial deposition site onto which the conditioned flocculated tailings are deposited for water release and drying. Alternatively, the dewatering unit 118 can be a mechanical dewatering device that separates the conditioned flocculated tailings into a water-depleted material and a water enriched stream. The transportation and conditioning assembly 116 is configured for transporting and conditioning the flocculation tailings material 114 from the chemical addition unit 110 to the dewatering unit 118.

[0033] In some implementations, the transportation and conditioning assembly 116 can be in the form of a pipeline having certain dimensions and configuration.
The transportation and conditioning assembly 116 can include multiple piping sections as well as one or more in-line shear devices, or can be limited to a pipeline without mixers or pipe internals (e.g., baffles) such that the shear conditioning is substantially imparted by pipe wall shearing as the material flows through the pipeline. The flocculation tailings material 114 can be considered as a mixture of flocculant and thick fine tailings that is in a state of flocculating or has been substantially flocculated and can be experiencing floc breakdown, as will be explained in further detail below. The transportation and conditioning assembly 116 can include an upstream floc build-up assembly or section that handles the material while in a state of flocculating and building up flocs, and a downstream floc breakdown assembly or section that handles the flocculating material as the flocs are being partially broken down. The transportation and conditioning assembly 116 can consist essentially of a pipeline such that the floc build-up and floc breakdown assemblies are part of the same overall pipeline with upstream and downstream pipe sections. Once deposited or otherwise subjected to dewatering, the resulting release water 120 can flow away from the flocculated solid matrix and be recovered by a water recovery assembly 122 for recycling as recycle water 123 into mining operations, extraction operations, water treatment facilities or other operations requiring process water.

[0034] Various rheological changes can occur as the thick fine tailings 104 progress through stages of a flocculation process. Depending on the particular flocculation and dewatering process being used, the stages of the flocculation process can have different characteristics, as will be explained further below. Certain of these rheological changes will be described with reference to Figs 2a and 2b.

[0035] Fig 2a illustrates flocculation stages for an example flocculation and dewatering process that uses the addition of a flocculant solution to produce a flocculated material for which large and rapid initial water release is desired upon deposition on a sub-aerial land surface or into dewatering device. For instance, the flocculated material can be deposited in thin lifts onto a sloped beach or deposition cell made of sand or the like, allowing release water to separate and drain from the flocculated solids, and flow away from the deposited material. In this context, it is desirable to initiate dewatering by depositing the flocculated material or otherwise allowing water to be released from the flocculated material within the maximum water release zone.

[0036] On the other hand, Fig 2b illustrates flocculation stages for another example flocculation and dewatering process that uses the addition of a coagulant and a flocculant to produce a flocculated material for deposition into a settling structure, such as a pit, and allowing the water to separate from the flocculated solids by settling mechanisms, eventually forming a permanent aquatic storage structure (PASS).
This type of process can be generally referred to herein as a PASS process.

[0037] First, there is a dispersion stage where the flocculant is rapidly mixed into the thick fine tailings and the flocculation begins, forming the flocculation tailings material.
The dispersion stage can be performed by injecting a flocculant solution that includes the flocculant into the flow of the thick fine tailings. Rapid and high-shear mixing can enhance this dispersion stage.

[0038] Next, there is a floc build-up stage where the flocculation tailings material increases in yield stress. In this stage, the flocculation tailings material can be considered as a flocculating material. As can be seen in Figures 2a and 2b, the flocculation tailings material increases in yield stress until it reaches a peak yield stress.
Up to and around this peak yield stress the flocculation tailings material can be said to be "under-sheared" because insufficient shear conditioning has been imparted and the flocculation tailings material is thus in a state that does not tend to release water at notable rates. In addition, below this peak point, complete or adequate dispersion of the flocculant may not have occurred. At high points on the yield stress curve the flocculation tailings material can form a gel-like material that does not tend to effectively release water if, for example, deposited and left to dewater. Continued shearing past the peak yield stress region, which can be a single peak point or an undulating plateau region, the yield stress of the flocculation tailings material will begin to decrease and enter the next zone, which will be discussed below. It is noteworthy that when there is effective dispersion of the flocculant into the thick fine tailings, the subsequent shear conditioning stage tends to be shorter as the peak yield stress is attained faster compared to when the dispersion stage is poorer or incomplete.

[0039] The next stage can be referred to as a floc breakdown stage or a water release stage, where the flocculation tailings material decreases in yield stress from the peak yield stress and in which the material can experience water release at notably higher levels, particularly in the short term. This stage includes a "water release zone"
where water is released from the flocculated matrix, for example at high short-term levels. Figure 2a, for example, illustrates a maximum water release zone beginning at a certain point within the floc breakdown stage, after the peak yield stress, and spanning a region of a shearing time interval in which the yield stress has decreased from the peak but not back to the original level of the thick fine tailings prior to flocculant dispersion. In this water release stage, the flocculated matrix takes on a more permeable state and water is released at high levels within the water release zone. As mentioned above, depositing or otherwise initiating dewatering of the flocculated material within this water release zone can be done for processes where a large initial or short-term release of water is desired, as is the case when flocculated material is to be deposited on a sub-aerial sloped surface to allow water to drain away from the deposited material.

[0040] Still referring to Figure 2a, there is an "over-shear zone", which is to be avoided and thus bounds the water release stage. In the over-shear zone, the flocs are broken down to a point that the material generally returns to a similar state as the initial thick fine tailings. Little to no water can release from the over-sheared material, as the floc structures have been sheared to a point where they can no longer enable meaningful permeability and water release.

[0041] Referring now to Figure 2b, for certain dewatering processes it may be desirable or advantageous to subject the flocculation tailings material to additional shear conditioning past the maximum short-term water release zone. For example, dewatering processes in which both a coagulant and a flocculant are added to the tailings can be subjected to further shear conditioning to improve long term water release from the material at the expense of the initial water release, and optionally to reach a target floc size that may be between about 50 pm and about 200 pm to enhance long term water release. The target floc size range can be pre-determined based on a minimum settling rate and a maximum settled volume within the PASS. Interestingly, addition of coagulant (e.g., alum, gypsum, or ferric sulphate) can prevent the permeability of the flocculated tailings from returning to the original tailings properties in response to additional shearing that would have otherwise resulted in overshearing without coagulant. For such processes, by using both coagulant and flocculant it is possible to use additional shearing past the short-term water release zone to create flocs that will have improved settling or consolidation characteristics, as the coagulant facilitates and increase in the permeability of the flocculate material. Thus, for such dewatering processes, where settling and consolidation are relevant mechanism to separate water from flocculated solid material in a PASS or similar structure, the flocculation reaction stages of interest can be different compared to dewatering processes that use only a flocculant and thin lift deposition and drying.

[0042] Figures 2a and 2b illustrate examples of flocculation stages that can be of interest for such processes. Figure 2c shows a comparison between these two processes and illustrates how the short-term dewatering process does not benefit from overshearing (i.e., high energy input) as the CST returns to its initial value, while the long-term PASS dewatering process can be relatively stable in terms of CST
water release even when higher energy is input into the flocculated tailings. (Note that low CST
corresponds to high water release.) It should be noted that other flocculation processes could have other stages of interest that could be evaluated by the automated analyzer.

[0043] Understanding of the flocculation stages mentioned above can facilitate enhanced operations for dewatering thick fine tailings, such as enhanced design and operation of the pipelines and mixing units as well as enhanced selection of polymer flocculants to be used in the process. In addition, various test methods can be developed to assess these flocculation stages in greater detail by analyzing samples of tailings and flocculants at different flocculation conditions. Testing samples can, in turn, facilitate enhancements in the design and operation of larger-scale thick fine tailings dewatering operations.

[0044] Some properties of the flocculation stages mentioned above can be characterized or estimated based on corresponding rheological changes of the MFT, such as changes in yield stress of the MFT as it experiences shear and flocculation reactions. Modeling the flocculation process of an MFT sample at the laboratory scale can allow testing various operating parameters, such as mixing regimes, the type and dose of the flocculant, the concentration of the flocculant dissolved in a solution, the position of flocculant injection ports, MFT properties, and so on. This can also facilitate assessment of the impact of certain operating parameters on the rheological changes of the MFT sample and its dewatering characteristics. The impact of MFT
properties, such as bitumen content, sand content, initial yield stress, viscosity, clay-to-water ratio (CWR), and sand-to-fines ratio (SFR), salt content, on the rheological changes of the MFT as the sample is subjected to flocculation can also be evaluated through laboratory scale analyses. Insights gained through the analysis and modeling of the flocculation process of an MFT sample at the laboratory scale can facilitate enhanced design, operation, adjustment and/or fine tuning of a larger scale flocculation and dewatering process.

[0045] It should be noted that other flocculation and dewatering processes can be used to treat different types of tailings. Some flocculation and dewatering processes involve in-line flocculant addition and conditioning followed by dewatering, while others can involve other steps and equipment. Some example flocculation and dewatering processes and associated techniques are described in CA 2701317, CA 2820324, CA
2820259, CA 2820660, CA 2820252, CA 2959035, and CA 2958873. The automated analyzer and associated methodologies described herein can be used in the context of analyzing and enhancing such processes.
Sample analysis and assessment of flocculant-tailings mixing properties

[0046] In order to facilitate efficient dewatering operations, it is desirable that the flocculation tailings material be subjected to dewatering (e.g., by depositing at a deposition site or feeding into a dewatering device) while within the water release zone.
Thus, methods that facilitate modeling the flocculation process and characterizing MFT
samples subjected to flocculation stages to identify factors relevant to effectively producing a flocculated material in the water release zone, can facilitate the design and operation of tailings dewatering processes. In particular, analysis of MFT
flocculation at the laboratory scale can facilitate the selection of operating parameters, such as flocculant type and/or dosing, which can enhance performance of the dewatering process. Indeed, the use of different flocculants on the same MFT material can result in different rheological behavior of the flocculated tailings material. For instance, achieving the water release zone can require more or less shear, and can also be narrower or larger, for different flocculants and different tailings samples, and this type of information can be useful for the design and operation of dewatering processes.

[0047] Depending on the test results on MET samples, the operation of the flocculation and dewatering process can be modified by changing operating conditions (e.g., flow rates, flocculent dosage, etc.) or by changing equipment (e.g., flocculent injectors having different configurations where the flocculant injection ports are different in size, number and/or position).

[0048] Various methodologies and equipment can be used to analyse the flocculation of thick fine tailings samples, and determine certain factors to help enhance flocculation and dewatering. For instance, an automated flocculation sample analyzer 400, examples of which are illustrated in Figures 6 to 8 and 11, can be used to assess impacts of mixing, flocculent characteristics, and tailings characteristics on the flocculation and dewatering processes. In addition, a methodology, such as the one schematically illustrated in Figure 4, can be used to assess impacts of mixing characteristics (e.g., macro-mixing, meso-mixing, and micro-mixing) on flocculation and dewatering processes. More regarding the automated flocculation sample analyzer will be discussed in detail further below.

[0049] In accordance with an aspect and with reference to Figure 4, there is provided a method for analyzing a thick fine tailings sample subjected to a flocculation treatment. First, a sample of MET is first provided 202. The thick fine tailings sample subjected to analysis can be a thick fine tailings sample retrieved from a tailings pond, or can also come from any other suitable source for which analysis of the sample is desirable. The thick fine tailings sample is placed into a mixing vessel, such as the mixing vessel illustrated in Figures 6 to 11. A flocculant is added 204 to the mixing vessel and is dispersed into the tailings sample to form a flocculation tailings material. In some implementations, the flocculent can be chosen according to the objective of the sample analysis, for instance to determine the flocculation performance with a given type of flocculent, or to determine the required dose of flocculent for a thick fine tailings sample having given characteristics.

[0050] During a flocculation process, the flocculant first mixes with clay contained in the thick fine tailings sample. The flocculant chains are adsorbed on the clay surface, rearrange themselves to form loops and tails, and the collision between the particles allows the formation of flocs, or aggregates, by bridging loops and tails and/or due to charge effects. This type of flocculation can be referred to as bridging flocculation. The reactions that occur when the flocculant bonds to the clay are known to be complex, and thus deriving the dominant mixing mechanism(s) can also be a complex task.
Hence, by varying factors that influence the micro-, meso- and macro-mixing regimes and assessing the impact of each of these mixing regimes on dewatering performance and as mentioned above, it is possible to determine which mixing scale or scales are potentially relevant for optimal flocculant dispersion and thus, in turn, proceed with proper scaling up by taking into account the dominant or relevant mixing regimes at play.
It is also noted that these mixing factors relate to the stages of the flocculation process that involve mixing, dispersion and floc build-up.

[0051] The flocculation performance can be assessed for instance by various water release values and/or flocculant characteristics (e.g., a 24 hour CWR, a peak water release in 24 hours, a net water release (NWR), flocculant dosage requirements, and yield stress evolution during the mixing operation). For example, the NWR can be calculated as follows, tMFT referring to treated MFT:
Water release from initial MFT [CWRml NWR = ______________________________________ =1 ________ Water in initial MFT " R tMFT

[0052] When the assessment of the flocculant is to inform the design or operation of a large-scale tailing dewatering operation, the flocculation and dewatering characteristics that are observed can be selected to be analogous to the larger scale operation. For example, some water separation processes are dominated by water drainage mechanisms, in which case a corresponding NWR value can be observed at the laboratory scale by draining the flocculated sample through a fine screen.
Other water separation processes are dominated by settling, in which case a settling rate may be measured for the flocculated sample.

[0053] The flocculants that can be tested can have various properties. For instance, the flocculant can be an anionic polymer flocculant, such as an anionic polyacrylamide flocculant, or an anionic polyacrylamide-sodium polyacrylate co-polymer flocculant. The flocculant can also be characterized by its average molecular weight and its charge. In some implementations, anionic flocculants having a high molecular weight and a medium charge have been shown to be particularly effective at flocculating thick fine tailings.

[0054] Referring still to Figure 4, shear conditioning is imparted to the mixture of flocculant and thick fine tailings sample through mixing 206. The dispersion of the flocculant in the thick fine tailings sample can be influenced by various parameters, such as the agitator type, the position of an impeller, the number and size of injection points to inject the flocculant into the mixing vessel, the concentration of the flocculant in the solution, the location of the injection points, the injection rate of the flocculant, the viscosity of the thick fine tailings sample and/or the viscosity of the flocculant solution.
Such parameters can, in turn, have an impact on the various stages of the flocculation process 208. By varying these factors and assessing the impact on the resulting dispersion of the flocculant, information regarding the contribution of mixing regimes, i.e., micro-, meso- and macro-mixing, to a flocculation process can be obtained.

[0055] It should be noted that the impact of mixing scales can be assessed in various orders or sequences using various different operating conditions for the analyzer. Figure 4 illustrates one possible methodology, but many other approaches can be used to evaluate variables and mixing scale impacts for the flocculation and dewatering process. More regarding the mixing scales is discussed below.

[0056] The automated mixer assembly described herein can be configured to be operable to assess three turbulence length scales, i.e., micro-, meso- and macro-mixing, which are different mixing regimes that exist and can each potentially impact the dispersion of the flocculant and the flocculation of the MFT. For example, the automated mixer assembly and other relevant components can be configured to test whether one length scale is more influential than another by adjusting settings such as mixer RPM, injection rate, and injection location.

[0057] The terms macro, meso and micro originate from the grouping of the turbulent eddies, which are present in turbulent flow, into three sizes ¨ big (macro), medium (meso) and small (micro). In terms of controlling the length scales, the automated analyzer can change the degree to which the micro scale extends down in size and, to a certain degree, the distribution within the entire range of length scales by adjusting the amount of energy that is imparted into the fluid. This energy drives the smallest length scale down in size to the point where viscous forces begin to dominate and energy contained within the smallest (micro) eddy can be dissipated as heat. The process of transferring energy from the largest eddies to the smallest ones is referred to as the energy cascade. When 'mixing' scales are discussed, it is referring to how a given system is influenced by the mixing that occurs over regions proportional in size to the particular group of length scales: marco-mixing (bulk, large scale mixing ¨
across the vessel), meso-mixing (intermediate scale mixing ¨ typically within a localized region of the vessel where intermediate length scales play a key role in dispersion, such as the location of flocculant injection), and micro-mixing (smallest scale ¨ where flocculant and clay interactions initially occur). As previously mentioned, the automated analyzer can be configured to test whether one length or mixing scale is more or less influential than another by adjusting various setting and parameters of the analyzer, and then measuring and comparing certain output variables.

[0058] In other words, in the case of the automated analyzer of tailings flocculation, micro-mixing refers to the smallest mixing scale (e.g., Kolmogorov length scale) and corresponds to a scale at which the energy is dissipated by viscous forces, i.e., at which the viscosity is dominant. Meso-mixing relates to the inlet or feed of one component into another, and refers to a turbulent dispersion of a feed stream (e.g., a flocculent feed stream in this case) into the tailings sample present in the mixing vessel. In other words, meso-mixing relates to inlet or feed effects on mixing. Macro-mixing refers to mixing at the scale of the impeller and the tank, and can be characterized by the coefficient of variation (CoV), for instance. The different mixing scales are present in turbulent flow, cascading/dissipating from large to small, with the process being continuous so as long as there is energy driving the system (e.g., an impeller keeps spinning or pipe flow keeps flowing) such that large eddies are created and then follow the energy cascade until they dissipate. Understanding the contribution of each of these mixing scales on the flocculation process and the controlling or dominant mixing parameters when reaction kinetics cannot be easily measured can potentially help in determining the extent and the type of shear conditioning to be imparted to the MET for optimal dewatering.
[00591 The dispersion of the flocculant can be performed by an automated mixer assembly 402, such as the one illustrated in Figures 6 to 8 and 11. The automated mixer assembly includes a mixer, such as an overhead mixer, and a motor. The motor can be for instance a synchronous motor or a servomotor. The motor can be configured to allow an operator to monitor different output values such as the torque exerted by the motor, and/or the speed of the motor. It is also noted that torque measurement can be used in general to track flocculation development and characteristics, and can be measured by obtaining motor torque, using a torque transducer mounted to the mixer shaft, or other torque measurement methods. A broad range of operating conditions of the motor in terms of torque and speed can advantageously allow to vary the mixing conditions. The motor is operatively connected to an agitator, such as an impeller via a shaft, to mix the thick fine tailings sample, disperse the flocculant, and provide the shear conditioning.
Different types of impellers can be used depending on the flow pattern to be achieved.
The impeller can be for instance a paddle impeller such as shown in Figures 6 to 8.
Various paddle or impeller designs can be used and can include single or multiple impellers on a single drive shaft.
[0060] The automated mixer assembly 402 can be operatively connected to a data acquisition system (DAQ) such that output values can be available and monitored by the operator. By monitoring such output values, the flocculation progression during mixing can be tracked, thereby allowing the operator to perform repeatable tests, for example by stopping the mixing at desired point(s) during the flocculation process and evaluating characteristics of the flocculating material at different stages of the flocculation process such as the gel state zone, the water release zone, and the over-sheared zone.
[0061] The impact of the mixing speed on dewatering performance can be assessed by changing the rotations per minute (RPM) of the impeller, or by changing the fast-slow timing and the RPM of the impeller. In this context, "fast-slow" refers to a sequence of mixing of the thick fine tailings sample at an initial fast RPM, which may provide a rapid dispersion of the flocculant in a turbulent flow, followed by mixing at a slower RPM, which may provide a slow laminar mixing stage. This type of fast-slow sample mixing mimics larger scale operations in which the flocculant dispersion is performed under turbulent high-shear conditions, and the subsequent shear conditioning (e.g., via pipeline) is performed under lower shear or laminar conditions. Changing the fast-slow timing can involve for instance changing the duration of one or each of the fast or slow mixing periods, and/or changing the RPM of one or each of the fast or slow mixing. If it is determined that modifications to the mixer speed or to the fast-slow timing has little to no impact on flocculation and dewatering performance of the thick fine tailings sample, then it can be concluded that mixing in general likely does not have a major impact on the flocculation process. In other words, none of the mixing scales mentioned above would be particularly relevant to flocculation performance. However, if mixing speed does have an impact on flocculation performance, then one or more of macro-mixing, meso-mixing and micro-mixing could be relevant and can be further assessed using the automated analyzer.
[0062] Figure 13 illustrates the impact of the impeller RPM on NWR, and shows that an increase in impeller RPM for the thick fine tailings sample tested results in an improved NWR. In other experiments, it was found that the best 24hr CWR was obtained when the floc efficiently creates a large chord length or floc size. On the other hand, when inefficient mixing occurs, e.g., when laminar flow occurred instead of turbulent flow, the flocculant was not well dispersed and the floc formation was not optimal, which in turn influenced the dewatering performance. Inadequate mixing can also result in a higher amount of flocculant being required to achieve sufficient floc buildup.
[0063] Once it has been determined that the mixer speed has an impact on the dispersion of the flocculant and mixing plays a role in the flocculation process, the next factor to be investigated can be the injection rate of the flocculant. The injection rate of the flocculant refers to the amount of flocculant over time that is injected into the tailings sample present in the mixing vessel. When testing this injection rate, the time over which a given amount of flocculant is fed into the mixing vessel can be changed for different runs. Varying the injection rate of the flocculant can be done either as a standalone step or by concomitantly varying the mixing speed. If the injection rate is found to have no effect on dewatering performance, it can be concluded that micro-mixing is the dominant mixing mechanism and should be taken into consideration to optimize the dewatering performance of the flocculated material. If this is the case, the viscosity of the thick fine tailings sample can be modified to control the mixing regime, e.g., so that the flow pattern remains a turbulent flow at the relevant times during flocculant injection and dispersion. In some tests, it was also found that the combination of a high RPM and a low rate of flocculant injection, as well as the combination of a slow RPM and a fast rate of flocculant injection, were not optimal for the dispersion of the flocculant and therefore were not desirable operating conditions for the tested MET, polymer flocculant and operating parameters. It was found that the ratio of RPM / flocculant flow rate can also be a valuable tool to control micro-mixing. This ratio can be of particular importance since it was noted that the effectiveness of the flocculation process can be reduced if too much energy is imparted after injection.
[0064] If the feed time of the flocculant is found to have little to no impact on the dewatering performance, the next investigative step can be to determine the impact of the position of the injection points on dewatering performance, to evaluate whether mesa-mixing is relevant. If mesa-mixing is relevant, then feed time should have an impact and so should the feed location and number of feed inlets. Thus, if feed time is found to have no impact, then assessment of the injection position and number of injection ports can be used to determine whether or not mesa-mixing plays any significant role. In other words, mesa-mixing can be ruled out as a significant mixing scale factor if assessments of feed time, injection location, and injection port number all result in little to no impact on the dewatering performance. For instance, for the system described in Figures 6 to 10, injection locations can be modified by injecting only in the lower set of ports, injecting in only the upper ports, injecting in only one port, and/or injection via specific combinations of ports such as a pair of ports on one half or side of the mixing vessel. It is noted that other injection points could also be evaluated, such as injection points at different heights of the mixing vessel, from the top of the vessel, exiting closer to or further from the impeller, and so on. Varying the position of the injection points can involve varying their position along the height of the mixing vessel, their distribution along the periphery of the mixing vessel and/or varying the angle at which the flocculant injected therethrough would enter the mixing vessel. If the position of the injection points is found to have no influence on dewatering, it can be determined that mesa-mixing does not play a relevant role in the overall mixing and that macro-mixing plays a role. On the other hand, if the position of the injection points is found to influence flocculation or dewatering, meso-mixing would be interpreted as being relevant for dewatering performance. In both cases, the number of injection points should be further evaluated. For instance, instead of having two injection points positioned opposite to one another, four injection points, for instance each positioned in a quadrant of the mixing vessel, can be used and the impact on dewatering can be evaluated. It has been found that increasing the number of injection points can increase the range of dosage of flocculant required to obtain a given dewatering performance. The number of injection points can also influence the dispersion of the flocculant such that more robust flocs can be obtained, which can be correlated to a greater increase in torque.
[0065] For instance, in some implementations and as shown on Figure 6, four pairs of injection points positioned at positions 3, 6, 9, and 12 o'clock are provided. Thus, the injection rate and the position of the injection points can be relied upon for the assessment of meso-mixing.
[0066] Referring to Figure 14, the relationship between the clay based dose (g/tonne) of flocculant and the 24hr CWR is shown for a standard injection of the flocculant into the mixing vessel and for an improved mixing taking into account meso-mixing considerations, such as the injection rate and the position of the injection points.
It can be seen that the improved meso-mixing resulted in a lower clay based dose for a corresponding improved 24hr CWR. Thus, by improving the meso-mixing of the flocculant and the tailings, it was possible to both reduce the flocculant usage and increase the dewatering rate, resulting in notably improved performance overall. By making modifications to the large-scale operation that take into account the meso-mixing improvements acquired from the sample analyses, corresponding improvements can be made to the large-scale process.
[0067] The following are some examples of design considerations that can be used for an MET treatment operation to optimize dewatering based on the knowledge obtained from the testing with the automated flocculation sample analyzer described herein. For instance, if mixing speed is found to be unimportant, a simple tee injection configuration can be used in the field. If only the macro-mixing is found to be important when testing is performed in the laboratory, dead zones should be reduced and a simple tee and a static mixer could be used in the field. If the micro-mixing and the macro-mixing are important, then the RPM of the mixer and the flow rate of the field system could be controlled. If micro-mixing is important, feed time is of lower relevance but viscosity is of higher relevance and can be reduced to improve performance (e.g., by shear thinning the MFT, by increasing temperature, and/or by reducing the flocculant concentration in the injected flocculant solution). If meso-mixing is important, then the rate of injection and the number of injection points can be controlled because, for example, side reactions could have detrimental effects. In addition, once the importance of micro-, meso- and macro-mixing on dewatering performance has been determined, corresponding equations and correlations can be used to decide on appropriate process designs in the field.
[0068] The effect of overmixing can be evaluated to determine the importance of the depositional energy, i.e., the amount of energy applied at deposition, and of the injection point position to the dewatering performance when micro-mixing has been found to influence dewatering performance. In the present context, overmixing relates more particularly to "overshearing" the flocs and refers to a flocculation stage where additional energy has been input into the flocculated material which results in dispersing the structure and resuspending the fines within the water. The flocs go through the floc buildup stage and then become oversheared if too much energy is imparted. Over-sheared thick fines tailings release and resuspend fines and ultrafines entrapped in the flocs back into the water, and is to be avoided since it is past the limit of the water release zone. Thus, if an overmixing the flocculated material has a negative impact on dewatering, then the injection point position and the depositional energy should be considered as important. On the contrary, if overmixing the flocculated material has no impact on dewatering, then the injection point position and the depositional energy may not be particularly important to process design and operation.
[0069] In some implementations, the concentration (wt%) of the flocculant to be added to the thick fine tailings sample can be varied to determine if there is an optimal concentration for any given mixing condition, or if the mixing conditions determine the optimal concentration of the flocculant. Experiments were conducted and have shown that, using the tested parameters, the mixing conditions appear to be the factor that influences the concentration of the flocculant that is optimal. This finding may entail that if a mixing system is changed, the concentration of the flocculant may also have to be varied when scaling up.
[0070] Another factor to take into consideration is the impeller length and geometry, which was found to influence the flocculation process and the optimal dose of flocculant in some cases. This effect was dependent on the size of the mixing vessel, since when the 5" impeller was used with a larger length scale impeller, a shift up in the 24hr CWR
and a shift down in polymer dosage was observed (see Figures 16 and 17). These two figures relate to 24 hr CWR versus dosage results from tests done on the 6 inch mixing vessel where two impeller sizes were tested with and without slots cut out of them.
Figure 16 relates to tests performed with a 5x1 inch impeller with and without slots cut out, and Figure 17 relates to tests performed with a 4.5 x 1.5 inch impeller with and without slots cut out. The cutting out of slots from the face of the impeller was done to adjust the length scales generated by the impeller as it rotates. Note that some of the critical geometric mixing ratios used for the 5x1 inch impeller tests were different than those in the 4.5x1.5 inch impeller tests. It has been found that different aspect ratios, such as the ones mentioned above, can have an impact on mixing properties.
[0071] In addition, other geometrical factors can be taken into consideration. For example, when certain mixing vessel and impeller geometries are used in combination, there can be other relevant geometrical characteristics of the system¨such as the height from the top of the impeller to the cap of the mixing vessel as well as the height from the bottom of the mixing vessel to the bottom of the impeller¨that can be considered when designing the automated analyzer and/or its components for assessment of certain mixing properties.
[0072] These various experiments have shown that meso-mixing and micro-mixing are important factors to consider for optimization of 24hr CWR. Meso-mixing and micro-mixing were found to be inversely correlated with 24hr CWR. The combination of micro-mixing and meso-mixing are considered important for best performance of the automated flocculation sample analyzer. Having determined the mixing scale(s) contributing to best dewatering performance using the automated flocculation sample analyzer, adjustments in the pipeline design and features can be done accordingly. For instance, if the meso-mixing scale is found to be the controlling mixing scale for a thick fine tailings sample and a flocculant having given characteristics, then it can be possible to scale up from the automated flocculation sample analyzer to the field with more reliable results. The equipment of the scaled-up flocculation pipeline system and its geometry can be adjusted to optimize the meso-mixing, which can involve modifying the features of an injection device used for in-line injection of the flocculant into a fluid flow of a pipeline of thick fine tailings, in order to increase water release (e.g., 24hr CWR) and/or reduce the flocculant dose.
[0073] With reference to Figures 18A and 18B, there is shown a pipeline including an injection device 602. As can be seen on these figures, the width of the injector 602 can vary, as well as the number and the diameter of the primary orifice 604 and the secondary orifices 606. For instance, reducing the diameter of the primary orifice 604 and/or secondary orifices 606 of the injector 602 and/or increasing the number of secondary orifices 606 can result in an improved flocculation performance and reduced polymer dosage, in some cases. If the automated analyzer tests indicate that meso-mixing is an important factor at given test conditions that are correlated with given large-scale operating conditions, then reliable estimates can be generated using the automated analyzer to assess changes in the large-scale operating conditions.
For instance, one could test the impact of a change in temperature using the automated analyzer, and then adapt the design or operation of the scaled-up process based on the automated analyzer results. If at lower temperatures the automated analyzer indicates that more flocculant injection ports and higher flocculant dosage are required to maintain a desired dewatering level, then the scaled-up process can be adjusted during colder periods, such as winter time, by using a different flocculant injector with more injection orifices and increasing the flocculant dosage by increasing its concentration in the flocculant solution or by increasing the injection rate into the flow of MFT.
Many variables can be assessed using the automated analyzer in order to generate reliable process adjustments for the scaled-up dewatering operation.
[0074] It is noted that the automated analyzer, such as the one shown in Figures 6 to 8, has a drive shaft that extends vertically down a center axis of the mixing vessel, and is generally symmetrical about that axis. Such a centered, symmetrical configuration can be advantageous when the scaled-up flocculant injection device is also generally symmetrical about a vertical axis (not shown) or about a horizontal axis (as shown in Figures 18A and 18B).
[0075] In some implementations, the progression of the MFT through the various stages of the flocculation process can be assessed by measuring torque (of the motor or a transducer) and the rotation speed of the mixer. In Figure 3, an example of a relationship between the torque, in N=cm, exerted by the mixer, as well as the speed, in RPM, of the mixer as a function of time is illustrated. In this example, as the MFT sample is progressively mixed, the torque remains relatively constant at about 9 I\1=cm for approximately 15 seconds. This initial mixing time can be interpreted as corresponding to the period when flocs of MFT are forming and building up. Then, during the next about seconds of mixing, the torque exerted by the motor increases sharply and reaches a peak at about 13 N=cm, which corresponds to the peak yield stress of the flocculating material. As mentioned above, up to and around this peak torque value, the flocculation tailings material can be said to be "under-mixed" because insufficient mixing or conditioning has been performed to begin to breakdown the flocculated matrix and allow increased water release. Then, the torque imparted by the motor progressively drops below the initial torque value, at approximately 7 N.cm. The relatively rapid drop in torque is expected to be associated with the breakdown of the flocs.
[0076] According to this example, the peak torque can thus be used as an indicator of the transition of the MFT from the floc buildup stage to the floc breakdown stage. This peak torque can be a useful piece of information to identify the beginning of the water release zone and to avoid over-shearing the flocs, for a given MFT sample under study.
It then becomes possible to evaluate the effect of a number of factors on the parameters of the water release zone, such as the time interval and the corresponding extent of yield stress. The impact of mixing conditions and various other factors, such as flocculant dose, number of injection ports, location of injection ports and the extent of mixing on the water release zone parameters can then be determined, which can eventually translate into the ability to optimize the dewatering of the flocculating material.
[0077] In addition, through variations in the mixing conditions during the dispersion of flocculant into the MFT sample, the flocculation performance can be improved by adjusting mixing parameters such as, but not limited to, the turbulence mixing scales, the shear rate, the impeller type, the impeller RPM, and the flocculant injection rate. In some implementations, the flocculation performance can be evaluated in terms of flocculant dosage requirements and dewatering of the flocculated MFT. For instance, it can be desirable to reduce the amount of flocculant required for the flocculation process to reduce the costs associated with the process, and optimized dewatering of the flocculated MFT can translate into an increased amount of water being released from the flocculated MFT, which is desirable. This information can then be applied to an in-line mixing system to fine tune flocculant injector design, for example. The information can alternatively be used to design or operate other types of equipment for adding and mixing a dewatering chemical (e.g., flocculant) into thick fine tailings materials.
Automated flocculation sample analyzer [0078] Described in further detail below is an automated flocculation sample analyzer for analyzing various parameters of an MFT sample as the sample is subjected to a flocculation process. In some implementations, the automated flocculation sample analyzer as described herein can be used for instance to scale up from bench testing to large scale continuous processes.
[0079] With reference to Figure 5, a schematic representation of an automated flocculation sample analyzer 300 is shown. The automated flocculation sample analyzer 300 can include several components for modeling the flocculation process and characterizing the rheological properties of the flocculating material as the MFT sample is subjected to the flocculation process. The automated flocculation sample analyzer 300 includes a mixing vessel 302, an automated mixer assembly 304 and an automated injection assembly 306. The mixing vessel 302 includes a bottom part 305 and side walls 308 extending from the bottom part to define a mixing chamber 310. The mixing vessel 302 is configured to receive a volume of MFT 312, which may be a pre-determined volume, in the mixing chamber 310. For instance, in some implementations, the mixing vessel 302 includes a 6" diameter mixing vessel of approximatively 750 mL.
This volume can advantageously accomodate a sufficient amount of MFT for proper modelling of the flocculation process with regard to scale up processes, and/or an adequate volume to allow sufficient flocculating material to be tested and analyzed. However, it is to be understood that other dimensions of the mixing vessel 302 can be used. The mixing vessel 302 can include baffles, which can contribute to improve mixing performance and prevent undesirable flow patterns. Using a mixing vessel 302 with such characteristics and geometry for MFT flocculation can advantageously resemble and model typical stirred tank applications.
[0080] The automated mixer assembly 304 includes a mixer 314 and a motor 316.
The mixer 314 can be for instance an overhead mixer, or can be any other type of mixer that provides an adequate mixing of the MFT 312 so that the MFT 312 can progress through the stages of the flocculating process. In some implementations, the mixer 314 includes a paddle impeller, for instance a paddle impeller having a 5"x1"
size. The mixer 314 can be driven for instance by a synchronous electric motor, or by a servomotor. The use of a servomotor to drive the mixer 314 can facilitate imparting a broader range of speed and torque values, which can advantageously widen the range of tailings material that can be subjected to modelling using the automated flocculation sample analyzer 300.
[0081] The automated mixer assembly 304 and the automated injection assembly are operatively connected to a data acquisition system 318. In some implementations, the mixer 310 of the automated mixer assembly 304 is chosen such that output values related to the speed and torque of the mixer assembly 304 can be relayed to the data acquisition system 318 and subsequently to a computer, a database and/or a display screen. In other implementations, when using a synchronous motor, the torque measurements can be obtained indirectly from the motor current.
[0082] The automated injection assembly 306 is in fluid communication with a flocculant supply 320. In some implementations, the automated injection assembly 306 includes a servomotor operatively connected to a linear actuator, such that the linear actuator can impart a linear movement to a piston of a syringe to inject a given volume of flocculant in the mixing vessel 302. In some implementations, the volumes of flocculant injected in the mixing vessel 302 can be for example up to approximatively 200 mL. At least one injection line is connected to the syringe to inject the flocculant into the mixing vessel 302 at strategic position(s), which can be determined for instance in relation to the mixing patterns and shear zones within the mixing vessel 302. For instance, the injection locations can be proximate to the impeller.

[0083] Referring to Figures 6 to 8, there is shown an implementation of an automated flocculation sample analyzer 400 where the features are numbered with reference numerals in the 400 series, which generally correspond to the reference numerals of the schematic representation shown in Figure 5.
[0084] In the implementation shown in Figures 6 to 8, the automated flocculation sample analyzer 400 includes a mixing vessel 402, an automated mixer assembly and an automated injection assembly 406. The automated mixer assembly 404 and the automated injection assembly 406 are mounted to a support 401 including a base 403, a vertically extending post 411 and a horizontally extending platform 407 configured to support the automated mixer assembly 404 and the automated injection assembly 406.
In the implementation shown, the mixing vessel 402 is mounted to the vertically extending post 411 through a mixing vessel support assembly or bracket 409. It is to be understood that other configurations of the support 401, to combine the mixing vessel 402, the automated mixer assembly 404 and the automated injection assembly 406, are also envisioned and are within the scope of the present description.
[0085] With reference to Figures 9 and 10, baffle openings 413 are defined in the side walls of the mixing vessel 402 such that baffles (not shown here) can be mounted thereto, for example with fasteners, to extend within the mixing chamber of the mixing vessel 402. Alternatively, other means for mounting baffles inside the mixing chamber of the mixing vessel 402 can also be used. The type of baffles, their dimensions and their positions in the mixing chamber can be chosen for instance according to the mixing pattern to be modelized. In addition, injection port openings 415 are defined in the side walls of the mixing vessel 402 and are each configured to receive a corresponding injection line 432 of an injection port 430, as will be described in more detail below.
[0086] Turning back to Figure 6 to 8, in some implementations, a lid or a mixing cup plug 436 can be used in combination with the mixing vessel 402 to contain the MFT
sample and the flocculant within a mixing region of the mixing vessel 402.
This combination of the mixing vessel 402 with the lid 436 can contribute to improve estimates of parameters evaluating energy dissipation, and subsequent corresponding mixing parameters.

[0087] Still referring to Figures 6 to 8, the automated injection assembly 406 is in fluid communication with a flocculant supply 420 through a distribution line 422. The injection line 422 can be for instance a tube made of polymer or any other suitable material to transport the flocculant from the flocculant supply 420 to the automated injection assembly 406. In the illustrated implementation, the automated injection assembly 406 includes a servomotor operatively connected to a linear actuator 424, such that the linear actuator 424 can impart a linear movement to a piston (not shown here) of a syringe 426 to inject a given volume of flocculant into the mixing vessel 402.
Thus, the distribution line 422 connects the flocculant supply 420 to the syringe 426, and the flocculant is transported to the mixing vessel 402 through a primary injection line 428. In the implementation shown, the distribution line 422 connects to the syringe 426 through a 3-way electric actuated ball valve 425.
[0088] In some implementations and as illustrated in Figure 6, a first splitting assembly 430 can be used such that the primary injection line 428 can be split into a given number of secondary injection lines 432 to inject the flocculant at more than one location in the mixing vessel 402. In the implementation shown, the primary distribution line 426 splits into four secondary distribution lines 432 through a 4-way polymer manifold, each one of the secondary distribution lines 432 then splitting into two tertiary distribution lines 434 through a secondary splitting assembly 436 for a total of eight tertiary injection lines 434. Each one of the eight tertiary injection lines 434 connects to a corresponding one of the eight injection ports 438 positioned in a bottom section of the mixing vessel 402.
[0089] As mentioned above, the number of injection ports 438 and their position around the periphery of the mixing vessel 402 and along a height thereof can vary depending on the factors under study and the modelling to be achieved. For example, multiple injection ports 438 can increase the capability of testing the effects of turbulence mixing scales, with a focus on the role that meso-mixing can play in optimizing flocculant dosage requirements and overall design. In some implementations, the flocculant can be injected into the mixing vessel 402 near the surface of the volume of MFT.
Alternatively, in other implementations, the flocculant can be injected underneath into the bottom of the volume of MFT sample near a high-shear region of the mixing vessel 402.
Injecting the flocculant near a high-shear region of the mixing vessel 402 can facilitate the mixing of the flocculant with the MFT sample, which in turn can contribute to improve the repeatability and/or reproducibility of the model variables. Examples of injection rates of the flocculant into the mixing vessel can be from about 1 to 100 mL/s. It can also be useful to have injection ports that are located so as to be able to inject into different shear regions of the MFT sample being mixed, to evaluate the impact of shear at the injection point of the flocculant (e.g., one or more injection ports injecting into lower-shear regions spaced away from the impeller, and one or more injection ports injecting into high-shear regions proximate to the impeller).
[0090] The mixer assembly 404 of the automated flocculation sample analyzer includes a mixer 414 and a motor 416 to control the mixing regime imparted to the MFT
sample and the flocculating mixture after flocculant addition. In the implementation shown, the motor 416 of the mixer assembly 404 is a servo motor, which can advantageously allow operation of the mixer 414 over a wide range of conditions, for instance with respect to the speed of the mixer 414 and the torque exerted, which can allow for a broad range of materials having different characteristics in terms of rheology and solids content for instance to be tested with the automated flocculation sample analyzer 400. In the implementation shown, the mixer assembly 404 further includes a torque transducer 440 for measuring the torque exerted by the motor 416 during mixing of the MFT. In some implementations, the torque transducer can allow obtaining data such as bulk apparent viscosity values.
[0091] Referring now to Figure 11, there is shown another implementation of an automated flocculation sample analyzer 500 wherein the features are numbered with reference numerals in the 500 series, which correspond to the reference numerals of the implementation shown in Figures 5 and 6 to 8.
[0092] The automated flocculation sample analyzer 500 includes a mixing vessel 502, an automated mixer assembly 504, and an automated injection assembly 506.
The mixing vessel 502 can have for instance a diameter of 6" and have a volume of approximately 750 mL. In some implementations, the mixing vessel 502 includes baffles to improve mixing performance. The volume of the mixing vessel 502 and the inclusion of baffles are chosen to provide appropriate geometry for flocculation of the thick fine tailings sample based on typical stirred tank applications and a sufficient volume to allow subsequent rheology characterization testing on the thick fine tailings sample.
[0093] The automated mixer assembly 504 includes a mixer 514 to control the mixing regime imparted on the MET sample and a motor 516. The mixer 514 includes a paddle impeller 517, for instance a 5"x1" paddle impeller. The paddle impeller 517 can be chosen to allow variations in the turbulent mixing regime imparted on the thick fine tailings sample and to vary the integral length scale of the paddle impeller 517. In particular, as mentioned above, the size of the paddle impeller 517 and the characteristics of the optional slots defined in the paddles can have an impact of the impeller length scale which, in turn, can influence the dewatering performance and the optimal dose of the flocculant. The mixer 514 is operatively connected to the motor 516, and the motor 516 is operatively connected to a data acquisition system (DAQ).
The DAQ allows to measure the torque and speed imparted to the sample being analyzed, in particular to track the evolution of the sample as it goes through the flocculation stages, such as gel stage, optimal water release zone, and the overshearing zone.
[0094] The mixing vessel 502 is mounted to a support 501 that includes a base 503, a vertically extending post 511 and a vertically extending support member 519.
The vertically extending member 519 is connected to the vertically extending post through a connecting element 521. It is to be understood that other configurations of the support 501 are also possible in order to support the automated mixer assembly 504 so that the paddle impeller 517 of the mixer 514 can be positioned adequately, i.e., at a given height in the thick fine tailings sample depending on the experiments to be performed. The mixing vessel 502 is mounted to the vertically extending support member 519 through a mixing vessel support assembly 509.
[0095] The automated injection assembly 506 is in fluid communication with a flocculant supply 520 through a distribution line 522 and includes a servomotor operatively connected to a linear actuator 524. The linear actuator 524 can impart a linear movement to a piston (not shown) of a syringe 526 to inject a given volume of flocculant into the mixing vessel 502. The distribution line 522 connects the flocculant supply 522 to the syringe 526. A primary injection line 528 then connects the syringe 526 to the mixing vessel 532 through two secondary injection lines 532, the primary distribution line 523 being split into the two secondary injection lines 532 through a splitting assembly 530.
[0096] While two possible configurations of the automated analyzer are shown in Figures 6 to 8 and 11, it is noted that various other arrangements are possible. The configuration of Figure 6 to 8 can present certain advantages, such as having the mixing vessel 502, the automated mixer assembly 504, and the automated injection assembly 506 mounted on a single frame system, which can enhance operability, stability and relocation of the analyzer. The analyzer configuration of Figures 6 to 8 also has an advantageous number of distribution of flocculant injection ports, which can facilitate assessment of the impact of certain mixing scales, such as meso-mixing, on the flocculation process.
[0097] The automated mixing assembly can also be configured to impart a pre-treatment mixing to the thick fine tailings sample prior to injection of the flocculant solution. For example, the mixing assembly can be controlled to start mixing well before the flocculant injection to impart shear sufficient to reduce the viscosity of the sample, which is also referred to as pre-shear thinning. This can be useful to assess the impact of pre-shear thinning on subsequent flocculation characteristics. Other pre-treatments of the tailings sample can also be assessed, such as the addition of another chemical compound (e.g., coagulant, secondary flocculant, and so on). The injection assembly can in some cases be configured to include multiple injection setups for injecting more than one chemical compound at the same or different times. The automated analyzer can thus be used to assess the impact of different pre-treatments and/or the effects of different chemical additive combinations.
[0098] The automated analyzer can be used off-line in the laboratory or in the field as an at-line analyzer in some cases. It can be used prior to designing a large-scale operation to improve the process design and equipment sizing, and/or as part of ongoing operational improvements to an existing large-scale operation. It some cases, when an existing large-scale operation is to be modified (e.g., by treating tailings from a different source or by changing the flocculant type or concentration), the automated analyzer can be used to facilitate such modifications by pre-testing relevant variables [0099] For the purposes of disclosure, it should be noted that analyzers and components thereof illustrated on Figures 6 to 11 can be considered to scale.
Of course, such example dimensions should not be considered as limiting in terms of the many different analyzer designs and configurations that can be used.
EXPERIMENTATION
[00100] Experiments were conducted to illustrate some aspects of the methods and systems described herein to analyze MFT samples and flocculation of such samples. It is also noted that the automated analyzers as described herein have facilitated the acquisition of relevant data on the flocculation of thick fine tailings, with particular improvements compared to manual techniques of bench scale testing. The automated analyzer has notably enabled improved reliability compared to manual testing.
[00101] Figure 12 shows a scatter plot of experimental results obtained from the modelling of a flocculation process using a mixing vessel having a diameter of 4"
(circles), in comparison with a mixing vessel having a diameter of 6"
(squares). The graph illustrates the relationship between different dosages of flocculant based on the clay content to the MFT and the 24h CWR. The circles represent the results when no mixing parameter is adjusted, whereas the squares represents the results when mixing parameters, such as mixing scales, shear rate, impeller type and RPM and polymer injection rate were adjusted. These results show that adjusting mixing parameters has the potential to influence the dewatering performance of flocculated material, and having access to a wider range of mixing scales facilitated by the analyzer can make it possible to evaluate the contribution of each to the dewatering performance.
[00102] Table 1 shows various specifications of an example automated flocculation sample analyzer. The configuration of the 4" mixing vessel is provided for comparison purposes.
Table 1 4" mixing vessel 6" mixing vessel 6" mixing vessel 3" x 1" impeller 4.5" x 1.5" impeller 5" x 1" impeller Tank Diameter, T 4.00 6.00 6.00 Impeller Diameter, 3.00 4.50 5.00 Impeller Blade 1.00 1.50 1.00 Height, W
Impeller 0.23 0.40 0.20 Clearance, C
Baffle Width, B NA 0.25 0.25 MFT Volume (mL) 300 1013 650 Liquid Height, H 1.46 2.19 1.40 DTI 0.75 0.75 0.83 W/D 0.33 0.33 0.20 C/T 0.06 0.06 0.03 HIT 0.36 0.36 0.23 W/H 0.69 0.69 0.71 B/T NA 0.04 0.04 [00103] Figure 13 illustrates the .. impact of the impeller RPM on NWR for experiments conducted using an automated analyzer. Different impeller RPMs were tested for different MFT samples and the NWR was measured for each. The same flocculant and other conditions were used for the tests. Figure 13 shows that an increase in impeller RPM for the thick fine tailings sample tested resulted in an improved NWR over the tested conditions.
[00104] Figure 14 shows an improved dewatering performance of flocculated thick fine tailings when factors affecting meso-mixing were optimized. The figure illustrates that the 24hr CWR increased from about 0.37 to about 0.52 for a same clay based dose of the flocculant (around 1200 to 1400 g/tonne) when meso-mixing was taken into consideration, for instance by adjusting the feed time of the flocculant injected in the mixing vessel and the position of the feed points, compared to standard starting injection conditions.
[00105] Note that for tests that have been conducted, the standard starting injection conditions included injecting from a single injection location (which can be considered from a single pair of ports located at the same location around the perimeter of the mixing vessel). Certain feed rates can be established as the standard starting feed rate, based on existing data or other factors. The injection location can then be modified by injecting via two, three and/or four injection locations simultaneously, and/or injection via any combination or permutation of injection ports that are provided in the mixing vessel.
Obtaining data for many different configurations of injection location can provide useful indications on the impact of location on mixing and flocculation.
[00106] It is also noted that in various experiments that have been conducted, certain tests have been prioritized to assess mixing characteristics. Various experimental designs can be set up to assess mixing and flocculation of a flocculant-tailings system, a coagulant-flocculant-tailings system or another such system. However, in conducted experiments, the following parameters of the analyzer were modified: (1) mixer speed in the form of changing RPM of the mixer (also called performing an RPM sweep);
(2) flocculent injection rate with location fixed (e.g., location can be a single location around the perimeter of the vessel or, in the illustrated analyzed, a single pair of injection ports);
and (3) location of flocculant injection where various different ports or pairs of ports are tested at a single injection rate or at different injection rates. Additional variable testing can also be done, such as (4) geometry changes, such as impeller size or configuration, mixing vessel size, relative sizes or ratios of mixer components, and so on.
These variables can be assessed for a given or different flocculants, flocculant combinations (i.e., multiple flocculants), coagulant-flocculant combinations, coagulants, other chemical additions, tailings course/properties, pre-treatments, and so on. It is noted that it is relatively difficult to completely isolate the impact of a given mixing scale, particularly when conducting only a limited number of experiments. The experimental design can be set up and performed to obtain flocculation data at many different conditions, and then the data can be analyzed to assess the impact of various factors, including mixing scale, for scale-up purposes and future testing.
[00107] It is noted that in general the automated analyzer can be used to perform a variety of tests on thick fine tailings samples. A batch of tailings can be provided and multiple samples can be tested under different conditions using the analyzer.
For each sample, certain conditions including mixing parameters, flocculant type and dosage, injection location, can be fixed and recorded. During mixing and flocculation, data can be acquired, such as torque data to indicate yield stress evolution and flocculation stages.
After mixing/flocculation, each sample can be subjected to a post-flocculation assessment, which will typically be a water release test where the flocculated sample is allowed to drain or otherwise subjected to a bench-scale dewatering step. The dewatering characteristics are then recorded. Based on the flocculation conditions, the acquired flocculation data, and the acquired dewatering data for the respective samples, trends and relevant characteristics can be identified and then recommended operation conditions can be correlated to a scaled-up flocculation and dewatering process.
[00108] It is also noted that depending on the scaled-up flocculation and dewatering process that is being modelled, the flocculation and dewatering tests can be adapted.
For example, when the scaled-up dewatering process uses sub-aerial deposition of the flocculated material onto sloped areas in thin lifts to promote water release and drainage, the bench scale dewatering characteristics of the flocculated samples can be focused on drainage using, for example, a NWR measurement after a certain amount of drainage time through a screen or sieve. Alternatively, when the scaled-up dewatering process uses deposition of the flocculated material into a large pit to promote the formation of a permanent aquatic storage structure (PASS), the bench scale dewatering characteristics of the flocculated samples can be focused on settling rates and the like. If other dewatering devices that leverage different dewatering mechanism are to be used, then corresponding bench scale tests can be used. Thus, the automated analyzer can be used in the context of enhancing various different types of large-scale flocculation and dewatering operations. For the dewatering tests of the samples, additional equipment can be provided either as part of the automated analyzer or as a distinct apparatus.

Claims

35

1. An automated flocculation sample analyzer for analyzing tailings samples, comprising:
a mixing vessel for receiving a tailings sample and comprising multiple flocculent injection ports;
a flocculent supply unit to receive a flocculent solution to be supplied into the mixing vessel;
an automated injection assembly to inject a given amount of the flocculent solution into the mixing vessel, the automated injection assembly comprising:
injection lines in fluid communication with the mixing vessel through respective flocculent injection ports;
at least one supply line in fluid communication with the flocculent supply unit; and a pump assembly coupled to the at least one supply line and the injection lines cause of the given amount of flocculent to flow from the flocculent supply unit through the at least one supply line and the injection lines into the mixing vessel to contact the tailings sample;
an automated mixer assembly for mixing the tailings sample and the flocculent under different mixing regimes, the automated mixer assembly comprising:
a rotatable mixer located within the mixing vessel for contacting and mixing the tailings sample;
a drive shaft coupled to the rotatable mixer; and a motor coupled to the drive shaft to rotate the drive shaft and the mixer;
a data acquisition unit coupled to the automated mixer assembly to obtain at least one operating parameter therefrom related to flocculation of the tailings sample in response to mixing imparted by the rotatable mixer; and a controller coupled to the automated injection assembly and the automated mixer assembly for controlling flocculant injection and mixing.

2. The automated flocculation sample analyzer of claim 1, wherein the at least one operating parameter of the automated mixer assembly comprises torque exerted by the motor.

3. The automated flocculation sample analyzer of claim 1 or 2, wherein the at least one operating parameter of the automated mixer assembly comprises rotation speed of rotatable mixer.

4. The automated flocculation sample analyzer of claim 2, wherein the automated mixer assembly further comprises a torque transducer operatively connected to the drive shaft to measure the torque exerted by the rotatable mixer.

5. The automated flocculation sample analyzer of any one of claims 1 to 4, wherein the mixing vessel comprising at least one baffle.

6. The automated flocculation sample analyzer of any one of claims 1 to 5, wherein the pump assembly comprises an injection syringe comprising a hollow barrel and a plunger to force the flow of the flocculant solution.

7. The automated flocculation sample analyzer of claim 6, wherein the pump assembly comprises a linear actuator to actuate the plunger of the injection syringe.

8. The automated flocculation sample analyzer of any one of claims 1 to 7, wherein the automated injection assembly is configured to inject the given amount of flocculant into the mixing vessel in a subsurface region of the tailings flocculant sample.

9. The automated flocculation sample analyzer of any one of claims 1 to 8, wherein the multiple flocculant injection ports are located at a generally same elevation as the rotatable mixer.

10. The automated flocculation sample analyzer of any one of claims 1 to 9, wherein the multiple flocculant injection ports comprise at least one pair of injection ports located in vertically spaced-apart relation to each other.

11. The automated flocculation sample analyzer of any one of claims 1 to 10, wherein the multiple flocculant injection ports comprise at least two injection ports in opposed relation to each other on either side of the mixing vessel.

12. The automated flocculation sample analyzer of any one of claims 1 to 11, wherein the multiple flocculant injection ports comprise at least four injection ports located at a same elevation to each other and evenly spaced apart around a perimeter of the mixing vessel.

13. The automated flocculation sample analyzer of any one of claims 1 to 9, wherein the multiple flocculant injection ports comprise four pairs of injection ports evenly spaced apart from each other around a perimeter of the mixing vessel at 12 o'clock, 3 o'clock, 6 o'clock and 9 o'clock.

14. The automated flocculation sample analyzer of claim 13, wherein each pair of injection ports has an upper port and a lower port.

15. The automated flocculation sample analyzer of claim 14, wherein each upper and lower port is located at a same elevation as the other corresponding upper and lower ports, respectively.

16. The automated flocculation sample analyzer of claim 14 or 15, wherein each lower port is located adjacent to a bottom of the mixing vessel and at an elevation of a lower part of the rotatable mixer.

17. The automated flocculation sample analyzer of any one of claims 14 to 16, wherein each upper port is located at an elevation of a top part of the rotatable mixer.

18. The automated flocculation sample analyzer of any one of claims 1 to 17, wherein the multiple ports are operable in on/off mode so that the flocculant solution is injectable through one or more pre-determined ports for a given tailings sample.

19. The automated flocculation sample analyzer of any one of claims 1 to 18, wherein the mixing vessel further comprises a lid to contain the tailings sample and the flocculant in a mixing region of the mixing vessel.

20. The automated flocculation sample analyzer of any one of claims 1 to 19, wherein the motor of the automated mixing assembly is a synchronous motor.

21. The automated flocculation sample analyzer of any one of claims 1 to 19, wherein the motor of the automated mixing assembly is a servo driven motor.

22. The automated flocculation sample analyzer of any one of claims 1 to 21, wherein the automated injection assembly comprise splitters for splitters for supplying the flocculent solution to each of the injection lines.

23. The automated flocculation sample analyzer of any one of claims 1 to 22, wherein each of the injection ports is immobile.

24. The automated flocculation sample analyzer of any one of claims 1 to 23, wherein each of the injection ports is defined as an aperture extending through a side wall of the mixing vessel.

25. The automated flocculation sample analyzer of claim 24, wherein each of the injection ports are generally tapered in a downstream direction.

26. The automated flocculation sample analyzer of any one of claims 1 to 25, wherein the rotatable mixer comprises an impeller.

27. The automated flocculation sample analyzer of claim 26, wherein the impeller comprises a plate-shaped paddle.

28. The automated flocculation sample analyzer of claim 27, wherein the rotatable mixer has a single plate-shaped paddle.

29. The automated flocculation sample analyzer of any one of claims 1 to 28, wherein the drive shaft extends vertically along a center axis of the mixing vessel and the rotatable mixer is generally symmetrical about the vertical axis.

30. The automated flocculation sample analyzer of any one of claims 1 to 29, wherein the mixing vessel and the rotatable mixer are sized and configured with respect to each other to facilitate assessment of impacts of micro-mixing, meso-mixing and macro-mixing scales on the flocculation.

31. The automated flocculation sample analyzer of any one of claims 1 to 30, wherein the rotatable mixer has two opposed lateral ends that are located in spaced apart relation with respect to corresponding side wall surfaces of the mixing vessel.

32. The automated flocculation sample analyzer of any one of claims 1 to 31, wherein the rotatable mixer has a mixer height that is between 10% and 30% of a height of the mixing vessel.

33. The automated flocculation sample analyzer of any one of claims 1 to 32, further comprising a support frame to which the mixing vessel, the automated injection assembly, and the automated mixing assembly are mounted.

34. The automated flocculation sample analyzer of claim 33, wherein the mixing vessel, the automated injection assembly, and the automated mixing assembly are removably mounted to the support frame.

35. The automated flocculation sample analyzer of claim 33 or 34, wherein the motor of the automated mixing assembly is mounted to the support frame directly above the mixing vessel and the drive shaft extends vertically downward into the mixing vessel.

36. The automated flocculation sample analyzer of any one of claims 33 to 35, wherein the automated injection assembly is mounted to the support frame above the mixing vessel and beside the automated mixing assembly.

37. The automated flocculation sample analyzer of any one of claims 33 to 36, wherein the support frame comprises a base, a post extending upward from the base, and a platform extending outward from an upper portion of the post.

38. The automated flocculation sample analyzer of claim 37, wherein the motor of the automated injection assembly is supported by the platform.

39. The automated flocculation sample analyzer of claim 37 or 38, wherein the pump of the automated injection assembly is supported by the platform.

40. The automated flocculation sample analyzer of any one of claims 33 to 39, wherein the mixing vessel is mounted to the post.

41. The automated flocculation sample analyzer of any one of claims 33 to 40, wherein portions of the injection lines are mounted to the support frame.

42. The automated flocculation sample analyzer of claim 41, wherein the portions of the injection lines are mounted to the base.

43. The automated flocculation sample analyzer of any one of claims 33 to 42, wherein the mixing vessel is mounted to the frame via a height adjustment bracket.

44. The automated flocculation sample analyzer of any one of claims 1 to 43, wherein the mixing vessel defines a cylindrical mixing chamber.

45. The automated flocculation sample analyzer of any one of claims 1 to 44, wherein the motor is configured to operate at different rotation speeds.

46. The automated flocculation sample analyzer of any one of claims 1 to 45, wherein the automated injection assembly is configured to supply the flocculant solution in different predetermined volumes.

47. The automated flocculation sample analyzer of any one of claims 1 to 46, wherein the multiple injection ports are configured to be open or closed to enable the flocculant solution to be injected into the mixing vessel via different combinations of injection ports.

48. The automated flocculation sample analyzer of any one of claims 1 to 47, wherein the multiple injection ports have the same size and configuration.

49. The automated flocculation sample analyzer of any one of claims 1 to 48, wherein the automated mixing assembly is further configured to impart a pre-treatment mixing to the tailings sample prior to injection of the flocculant solution.

50. The automated flocculation sample analyzer of any one of claims 1 to 49, wherein the injection lines and the supply lines are flexible tubes.

51. The automated flocculation sample analyzer of any one of claims 1 to 50, wherein the tailings sample is a fine tailings sample.

52. The automated flocculation sample analyzer of claim 51, wherein the fine tailings sample is a thick fine tailings sample.

53. The automated flocculation sample analyzer of claim 51, wherein the tailings sample is a thin fine tailings sample.

54. An automated flocculation sample analyzer for analyzing tailings samples, comprising:
a mixing vessel for receiving a thick fine tailings sample and comprising at least one flocculant injection port;
a flocculant supply unit configured to receive a flocculant containing liquid to be supplied into the mixing vessel;
an automated injection assembly configured to inject the flocculant containing liquid into the mixing vessel, the automated injection assembly comprising:
at least one line in fluid communication with the flocculant supply unit and the mixing vessel for supplying the flocculant containing liquid via the corresponding at least one flocculant injection port; and a pump assembly coupled to the at least one line to cause the flocculant containing liquid to flow from the flocculant supply unit through the at least one line into the mixing vessel to contact the thick fine tailings sample;
an automated mixer assembly for mixing the thick fine tailings sample and the flocculant under different mixing regimes, the automated mixer assembly comprising:
a mixer located within the mixing vessel for contacting and mixing the thick fine tailings sample;
a drive shaft coupled to the rotatable mixer; and a motor coupled to the drive shaft to cause movement of the drive shaft and the mixer;

a data acquisition unit coupled to the automated mixer assembly to obtain at least one operating parameter therefrom related to flocculation of the thick fine tailings sample in response to mixing imparted by the mixer.

55. The automated flocculation sample analyzer of claim 54, further comprising one or more features as defined in any one of claims 1 to 53.

56. A method for analyzing tailings samples subjected to flocculation, the method comprising:
dispersing a flocculant into a tailings sample to form a flocculation tailings material;
subjecting the flocculation tailings material to mixing using an automated mixer assembly comprising a mixer operatively connected to a motor to impart shear conditioning and increase yield stress of the flocculation tailings material;
monitoring a torque exerted by the automated mixer assembly while the flocculation tailings material is subjected to mixing; and based on the monitored torque exerted by the motor of the automated mixer assembly, determining flocculation characteristics related to the corresponding mixing provided by the automated mixer assembly.

57. The method of claim 56, wherein the flocculation characteristics comprise at least one of the following flocculation stages: a dispersion stage wherein the flocculant is being dispersed into the tailings sample to form the flocculation tailings material; a floc build-up stage wherein flocs are building up and the yield stress of the flocculation tailings material increases; and a floc breakdown stage wherein water is released from the flocculation tailings material and the yield stress of the flocculation tailings material decreases.

58. The method of claim 56, wherein determining flocculation characteristics based on the exerted torque comprises identifying a peak torque value between the floc build-up stage and the floc breakdown stage.

59. The method of any one of claims 56 to 58, wherein subjecting the flocculation tailings material to mixing comprises providing a mixing regime to assess impacts of micro-mixing, meso-mixing and/or macro-mixing.

60. The method of any one of claims 56 to 58, wherein multiple samples are tested at different conditions to assess impacts of micro-mixing, meso-mixing and/or macro-mixing on flocculation and dewatering performance.

61. The method of claim 60, wherein multiple samples are tested by modifying at least one of a position of injection ports of the flocculant, a number of injection ports used for injection, a speed of the mixer, the torque exerted by the mixer, and a flocculant injection rate, to assess impacts of micro-mixing, meso-mixing and/or macro-mixing on flocculation and dewatering performance.

62. The method of any one of claims 56 to 61, wherein the analyzer as defined in any one of claims 1 to 55 is used.

63. The method of any one of claims 56 to 61, wherein the tailings sample is a fine tailings sample.

64. The method of claim 63, wherein the fine tailings sample is a thick fine tailings sample.

65. The method of claim 63, wherein the tailings sample is a thin fine tailings sample.

66. A method for enhancing performance of a tailings flocculation and dewatering operation, comprising;
analyzing a plurality of tailings samples using the analyzer as defined in any one of claims 1 to 55 or using the method as define in any one of claims 56 to 65;
modifying the tailings flocculation and dewatering operation based on the determined flocculation characteristics.

67. A method for enhancing performance of a tailings flocculation and dewatering operation, comprising modifying the tailings flocculation and dewatering operation based on flocculation characteristics determined from analysis of a plurality of tailings samples using the analyzer as defined in any one of claims 1 to 55 or using the method as define in any one of claims 56 to 65.

68. A method for designing or enhancing a tailings flocculation and dewatering operation comprising an in-line flocculant injector and a pipeline assembly, the method comprising:
providing samples of tailings to be treated;
analyzing the samples of tailings at different conditions, wherein analyzing each sample comprises:
dispersing a flocculant into a tailings sample to form a flocculation tailings material;
subjecting the flocculation tailings material to mixing using an automated mixer assembly comprising a mixer operatively connected to a motor to impart shear conditioning and increase yield stress of the flocculation tailings material;
monitoring a torque exerted by the automated mixer assembly while the flocculation tailings material is subjected to mixing; and based on the monitored torque exerted by the motor of the automated mixer assembly, determining flocculation characteristics related to the corresponding mixing provided by the automated mixer assembly;
designing or enhancing the tailings flocculation and dewatering operation based on one or more of the determined flocculation characteristics.

69. The method of claim 68, wherein the designing or enhancing of the tailings flocculation and dewatering operation comprises sizing and configuring a flocculant injection device for injecting the flocculant into the tailings.

70. The method of claim 69, wherein the flocculant injection device is an in-line injection device for continuous injection of a flocculant containing solution into a flow of tailings.

71. The method of claim 70, wherein the in-line injection device comprises a co-annular injector having a central tailing conduit and an annular injection component having a plurality of flocculent injection ports distributed there-around for injecting the flocculent containing solution into the flow of the tailings.

72. The method of any one of claims 69 to 71, wherein designing or enhancing the thick fine tailings flocculation and dewatering operation comprises modifying operating conditions and/or configuration of the flocculent injection device to enhance micro-mixing.

73. The method of any one of claims 69 to 72, wherein designing or enhancing the thick fine tailings flocculation and dewatering operation comprises modifying operating conditions and/or configuration of the flocculent injection device to enhance meso-mixing.

74. The method of any one of claims 69 to 73, wherein designing or enhancing the thick fine tailings flocculation and dewatering operation comprises modifying operating conditions and/or configuration of the flocculent injection device to enhance macro-mixing.

75. The method of any one of claims 68 to 74, wherein the analyzing step is performed using the analyzer as defined in any one of claims 1 to 55 or using the method as define in any one of claims 56 to 65.