Papers by Raymond Langlois
Minerals Engineering, 2016
Where a licence is displayed above, please note the terms and conditions of the licence govern yo... more Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.
An investigation into processing fine magnetite using a magnetic hydrocyclone
Canadian Metallurgical Quarterly
An investigation into the dry processing of low specific gravity ores using a laboratory Knelson concentrator
Canadian Metallurgical Quarterly
Physicochemical Problems of Mineral Processing
It has become an active research area for treating low specific gravity (SG) deposits by centrifu... more It has become an active research area for treating low specific gravity (SG) deposits by centrifugal separation due to its high efficiency, low cost and minor environmental impact. Laboratory Knelson Concentrator has shown its potential for processing high density ores on a dry basis. This study investigated the feasibility and the optimum operating conditions when processing a dry low SG feed with a modified Knelson Concentrator. A synthetic mixture of magnetite and quartz with a grade of 1% magnetite was used to mimic a low-density ratio ore. Bowl speed (G), air fluidizing pressure (psi) and solids feed rate (g/min) were chosen as the operating variables. Box-Behnken design was used to design the experiments and response surface method was used for optimization. The effects of each individual factors and their interactions on concentrate grade and magnetite recovery were evaluated. The dry process achieved up to 60 % magnetite recovery with an upgrade ratio of 5. The optimized val...
Minerals, Feb 11, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Comparison of Flotation of Cu-Ni Sulfide Ores Containing Different Non-magnetic/Magnetic Pyrrhotite Ratios
The floatability of non-magnetic (Non-Mag) & magnetic (Mag) pyrrhotite (Po) in Cu-Ni sulfide ores... more The floatability of non-magnetic (Non-Mag) & magnetic (Mag) pyrrhotite (Po) in Cu-Ni sulfide ores (chalcopyrite-pentlandite) is an important area of research that is receiving more attention as concentrators seek to remove more Po from their final Ni concentrate. Based on both lab-scale and industrial data available in the current literature, it appears both Po polymorphs exhibit different flotation responses mainly due to their surface chemical differences, which is the result of their different crystal structures. This preliminary study summarizes the bench-scale Denver cell flotation results (coarse and fines: +38 and -38um, respectively) of three Cu-Ni sulfide ore bodies containing 30%, 50%, and 95% Non-Mag Po (balance being Mag Po). The main goals were to assess whether Po type had an impact on total Po recovery and pyrrhotite-pentlandite (Po-Pn) selectivity both in the coarse and fines fractions, +38 and -38um, respectively. For the three ores (all size fractions combined), th...
Minerals Engineering, 2019
Where a licence is displayed above, please note the terms and conditions of the licence govern yo... more Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.
The Canadian Journal of Chemical Engineering, 2018
The emulsion liquid membrane technique was utilized to selectively extract copper and nickel from... more The emulsion liquid membrane technique was utilized to selectively extract copper and nickel from a synthetic aqueous solution containing calcium, which was used to mimic a tailings stream found in the Sudbury region of Canada. The results showed copper and nickel ions were successively extracted from the synthetic solution. Two central composite designs and an analysis of the experiments were used to optimize the process and determine the main effects and interactions of experimental factors. In the first stage, copper was extracted with a minimum removal of nickel and calcium. It was found that under optimum conditions 98 % of the copper was extracted, with only 0.9 % of the nickel and 1.3 % of the calcium being extracted. The subsequent copper stripping efficiency was 95.7 %. In the second stage, the remaining aqueous solution was treated to remove nickel with minimum calcium removal. During this stage, the corresponding nickel and calcium removal percentages were 99.0 and 0.55 %, respectively, with a nickel stripping efficiency of 84.1 %. Laboratory bench-scale tests using a two-stage mixer-settler showed a good correlation with these results when moving to a semi-continuous process, which extracted 99.7 % of the copper and 98.2 % of the nickel, with only 2.2 % calcium extraction.
Minerals Engineering, 2017
Dense medium separation (DMS) is a technique used to separate particles based on specific gravity... more Dense medium separation (DMS) is a technique used to separate particles based on specific gravity. Conventional DMS is, however, limited to coarse particle sizes and is not practical when processing fines. To improve the separation efficiency when processing fine particles, centrifugal separators have been employed. This work investigated DMS in a lab centrifuge and a modified Falcon Concentrator, in order to process the slimes of a rare earth ore. It has been shown that centrifugal concentration using a dense medium is possible when recovering values from a slimes fraction. Both the lab centrifuge and modified Falcon Concentrator resulted in a similar performance.
A comparison of the predictability of batch flotation kinetic models
Minerals Engineering, 2016
Abstract Batch flotation test data of a mixture of pyrite and calcite were used to compare regres... more Abstract Batch flotation test data of a mixture of pyrite and calcite were used to compare regression parameters of four kinetic model structures. The work included the use of unoxidized or a mixture of partially oxidized pyrite (by microwave irradiation). The objective of floating oxidized pyrite was to have mineral particles with different floatability, closer to a real situation. The models considered include: single rate constant, distributed rate constants (i.e. rectangular and gamma distributions), and a recently introduced approach based on fractional calculus. Such models were selected due to their good tradeoff between simplicity and accuracy. The regressions were performed (1) taking all the data points and comparing the mean square error (MSE) and adjusted correlation factor R Adj 2 as indicators of the goodness of fit; and (2) taking the first data points while neglecting the last ones (from 1 to 3) and observing the variability of the model parameters and the prediction of maximum recovery (R∞). For the latter regression scheme, besides MSE and R Adj 2 , a predictive factor, E, was defined by subtracting the final measured recovery from the calculation obtained by the model. This allowed to measure the ability of each model to extrapolate the omitted points on the recovery vs. time curve. Results from this study showed that the single constant model had a satisfactory performance with the advantage of having the least parameters compared to the other structures. The gamma model was effective and robust. The rectangular model gave an acceptable goodness of fit but overestimated the maximum and final recovery. Finally, the fractional calculus approach gave the best goodness of fit, overall, but failed in predicting the maximum recovery, which occurred when the derivative order was greater than 1.
Minerals Engineering, 2014
For the past 120 years, hydrocyclones have been used a wide variety of industrial applications, w... more For the past 120 years, hydrocyclones have been used a wide variety of industrial applications, with their main use in mineral processing being as a classifier. Hydrocyclone characterization relies heavily on empirical and phenomenological models. There is a need to develop a method by which the flow patterns can be quantified under industrial conditions. Positron emission particle tracking (PEPT), developed by the University of Birmingham in the late 1980s, has proven to be a powerful in situ visualization tool for engineering applications. This paper presents data on the motion of quartz particles in a two-inch hydrocyclone using the PEPT technique. Quartz tracer particles were labeled using the direct activation technique. The particle size range was between À2000 and +150 lm which illustrates the flow pattern of particles reporting to the underflow.
Speed analysis of quartz and hematite particles in a spiral concentrator by PEPT
Minerals Engineering, 2016
Abstract Activated quartz and hematite tracers between 1180 and 1700 μm in diameter were tracked ... more Abstract Activated quartz and hematite tracers between 1180 and 1700 μm in diameter were tracked in two sections of the first two turns of a spiral concentrator to ascertain information on valuable and gangue particle motion. The tracking took place while the tracer was flowing in a 20% solids by mass iron ore slurry. The direct activation of mineral particles, combined with the use of an adjustable height circular assembly of modular positron emission particle tracking detectors, has made this tracking possible. The tracer particle trajectories and speeds are presented in this paper. An early separation into two streams (concentrate or loss to tailings) can be seen for certain runs of the hematite tracers. Tracers speeds and radial position from the centre of the spiral give more details about the presence of the slurry film’s secondary flow in the middle zone of the spiral trough. Particle inward and outward migration speed in this secondary circulation is presented. The speed of this migration is approximately 0.12 m/s inward and 0.15 m/s outward for the set-up used.
Size-by-size analysis of dry gravity separation using a 3-in. Knelson Concentrator
Minerals Engineering, 2015
Observation of iron ore beneficiation within a spiral concentrator by positron emission particle tracking of large (Ø=1440μm) and small (Ø=58μm) hematite and quartz tracers
Chemical Engineering Science, 2016
Effect of microwave radiation on the processing of a Cu-Ni sulphide ore
The Canadian Journal of Chemical Engineering
ABSTRACT
PEPT Validation of a CFD-DEM Model of a Fine Quartz Particle (60μm) Behaviour in Stirred Water
Procedia Engineering, 2015
ABSTRACT A computational fluid dynamics (CFD) simulation of a Rushton impeller mixing water insid... more ABSTRACT A computational fluid dynamics (CFD) simulation of a Rushton impeller mixing water inside a baffled vessel was used to input steady state fluid drag forces into a discrete element method (DEM) simulation of a fine quartz particle of 60 μm freely moving inside the vessel. To validate the simulated behaviour of the particle, a modular positron emission particle tracking (PEPT) camera was used to track a real quartz particle of a diameter between 53 and 63 μm. The particle used as the tracer was created from a 1180 μm particle labelled with 18F radionuclide inside a cyclotron beam. A comparison of typical trajectory and velocities of the particle for both the model (CFD-DEM) and the measurement (PEPT) is presented. The results show that the simulation approach used is suitable to represent the behaviour of small particle of this type in water like fluid as similar trajectories and velocities are present.
A design of experiments investigation into dry separation using a Knelson Concentrator
Minerals Engineering, 2015
ABSTRACT Enhanced gravity, or centrifugal, separators have revolutionised gold processing over th... more ABSTRACT Enhanced gravity, or centrifugal, separators have revolutionised gold processing over the past decades, significantly increasing the recovery of fine (−100 μm) free gold. One of the main drawbacks of centrifugal gravity concentrators is the large volume of water required (even if it is all recycled). With water becoming an ever increasingly important “commodity”, reducing this is of importance both from an environmental and a monetary point of view. This work investigated operating a laboratory scale Knelson Concentrator with a dry feed and using air as the fluidising medium. The feed used was a synthetic mixture of tungsten and quartz, used to mimic a gold ore. The response surface method and central composite design techniques were used to design the experiments and to model the results, with the experimental variables being the bowl speed (G-Level), air fluidising pressure and the feed rate. The models corresponded well to the experimental results, indicating that for this experimental setup, the optimal conditions were a bowl G-Level of 40 G, a feed rate of 220 g/min and an air fluidising pressure of 8 psi.
PEPT studies of heavy particle flow within a spiral concentrator
Minerals Engineering, 2014
ABSTRACT Future improvements of gravity concentrators require an increased knowledge of the mecha... more ABSTRACT Future improvements of gravity concentrators require an increased knowledge of the mechanics behind the separation, including the motion of the particles. This work details the investigation of particle motion through a spiral concentrator. The results of tracking the motion of individual particles using the positron emission particle tracking (PEPT) technique are described. Tracer particles of different sizes and density were tracked along the trough of a laboratory scale spiral. Multiple passes of one tracer through the spiral are combined to represent the bulk of flow of this particle type and size, with the position and time recorded to allow for the particle trajectory and speed to be determined. Finally, the use of PEPT will be shown to be a powerful method to visualise the behaviour of particles during the concentration process, providing data that will be used for the validation of new models of spiral concentrator performance.
Minerals Engineering, 2013
Centrifugal gravity concentrators currently operate on a wet basis, with slurry feed and fluidisi... more Centrifugal gravity concentrators currently operate on a wet basis, with slurry feed and fluidising water used to enhance the separation based upon density differences. This work investigated the potential for running a laboratory scale 3 00 Knelson Concentrator on a dry basis. Air was used as the fluidising medium in order to separate tungsten from silica in a synthetic ore (1% w/w tungsten), and compared to an optimised wet proce ss. The wet processing attained a mean tungsten recovery of 94.92% (tungsten grade: 30.96 %). The dry processing at two different fluidising air pressures attained a recovery of 78.53% (tungsten grade: 6.32%) and 69.90% (tungsten grade: 15.57%) at 2 psi and 3 psi respectively. This preliminary work shows that it is feasible to separate minerals on a dry basis in a Knelson Concentrator.
Particle flow visualization in quartz slurry inside a hydrocyclone using the positron emission particle tracking technique
Minerals Engineering, 2014
ABSTRACT For the past 120 years, hydrocyclones have been used a wide variety of industrial applic... more ABSTRACT For the past 120 years, hydrocyclones have been used a wide variety of industrial applications, with their main use in mineral processing being as a classifier. Hydrocyclone characterization relies heavily on empirical and phenomenological models. There is a need to develop a method by which the flow patterns can be quantified under industrial conditions. Positron emission particle tracking (PEPT), developed by the University of Birmingham in the late 1980s, has proven to be a powerful in situ visualization tool for engineering applications. This paper presents data on the motion of quartz particles in a two-inch hydrocyclone using the PEPT technique. Quartz tracer particles were labeled using the direct activation technique. The particle size range was between −2000 and +150 μm which illustrates the flow pattern of particles reporting to the underflow.
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Papers by Raymond Langlois