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The ever increasing demand for energy and the progressive depletion of crude oil resources, have renewed interest in oil shale as an alternative fuel resource. Weathered oil shale samples were assembled from El-Nakheil phosphate mine in Quseir area, Eastern desert, Egypt. The oil shale samples were prepared and analyzed by XRD (X-ray diffraction), XRF (X-ray fluorescence spectrometry), and optical microscopic techniques. Rock-Eval pyrolysis and total organic carbon were used to study shale hydrocarbon potential. A leaching procedure using inorganic and organic acids was used to selectively dissolve the oil shale associated ash forming minerals. XRD results showed that calcite is the dominant carbonate mineral, whereas primary silicate minerals are quartz and montmorillonite. SEM (Scanning Electron Microscopy) observations indicated that the organic matter is dispersed throughout the rock matrix. The acid soluble fraction upon leaching was determined to be 37.59 and 42.74 wt% by using 5% HCl and 10% HCl, respectively. The TOC was increased from 20.78 to 29.88 and 34.09 wt% by using 5% HCl and 10% HCl, respectively. Keywords: el nakheil oil shale, characterization, xrd, xrf, sem, elemental analysis, proximate analysis, ultimate analysis, thin section, rock eval pyrolysis, acid leaching

Sep 1, 2012

By A. Üçyildiz

Magnesium borates of varying compositions and properties are synthesized using different reagents and methods for the possible potential uses as termoluminescent material, anti-wear and anti-friction additive, fire retardant, catalyst for the conversion of hydrocarbons, whisker material and ferroelastic material. In the current work, the conditions for synthesizing MgB4O7 compound by high-temperature solid-state reactions were investigated using boric acid and magnesium oxide as the starting materials. The MgO:B2O3 mole ratios applied in the experiments were 1:1, 1:2, 1:3 and the thermal behaviours of each mixture were studied between 25~1200°C by TG/DTA analyses under static air atmosphere to find out the probable formation temperature of MgB4O7 phase. Considering TG/DTA results, freshly prepared boric acid and magnesium oxide solid mixtures were heated at predeter-mined temperatures and the phases were identified by XRD analyses. Accordingly, MgO:B2O3 mole ratio of 1:2, heating temperature of 950°C and a reaction time of 2 hours were selected as the optimum conditions for the formation of maximum amounts of MgB4O7. After obtaining solids prepared at the pre-determined optimum conditions, their chemical composition, IR spectrum, TG/DTA pattern, B.E.T. surface area value, particle size distribution and SEM images were deter-mined to point out the possible use areas. Experimental results showed that it was not possible to obtain pure product at the optimum conditions due to formation of minor amounts of t-Mg2B2O5 and the presence of some unreacted B2O3. The product synthesized has the potential for use as a corrosion inhibitor on some metal surfaces.

Jan 1, 2014

Under the AMIRA P9 project the three-product cyclone-an off-shoot of the conventional hydro-cyclone-that produces three distinct products has been developed. The three-product cyclone shows great promise as a classifier in mineral processing. Industrial and pilot plant trials performed to assess its performance in the classification of the UG2 platinum ore, indicate that the presence of an extra overflow product stream that captures the mid-sized particles, provides improved classification efficiency. To assess the split on component density, samples from the feed and product streams were screened and assays by size for chromite (? = 4.8) and silica (? = 2.65) were obtained. Results from tests performed using this type of hydrocyclone in a number of applications indicates that it can be applied successfully in circuit configurations where the conventional hydrocyc-lone is not suitable. Utilising the three-product cyclone to classify the UG2 platinum ore resulted in an intermediate overflow product stream containing the mid-sized low density silicates and relatively fine high density chromite particles while the finer overflow contained mostly fine silicates and chromite particles. The coarse chromite and silicates reported to the underflow. Due to the increased number of products, the method of using efficiency curves was extended to cater for the increased number of products in the three-product cyclone. Although significant differences in the classification performance of the three-product cyclone were noticed with variations in machine variables a consistent method of assessing the performance was applied. The efficiency curve was adopted and applied and separate efficiency curve properties were obtained for each product stream. The methodology was applied to the component data, and efficiency curve proper-ties for each key component were obtained and compared. This paper discusses the application of the efficiency curve to cyclones producing more than two products and extending the methodology to the different components in the feed.

Jan 1, 2014

"The first 90 years of the last century generated a considerable volume of technical literature on the subject of grinding mill power and its prediction. It is therefore surprising that during this time there were no published models for predicting grinding mill power draw which were validated using a wide range of comprehensive industrial scale data.Notwithstanding this lack of data, the majority of models placed limited emphasis on the internal dynamics of mills and relied on simple assumptions which considered the charge to take up a fixed position and shape.Laboratory based studies (Liddell, 1986), and industrial data (Morrell, 1993), showed that these assumptions did not hold over a wide range of operating conditions, and brought into doubt the ability of the (then) existing models to accurately predict grinding mill power draw. Furthermore no model treated AG,SAG and ball mills as a single class of devices whose power draw could be predicted with the same equations.Through a detailed investigation of the charge dynamics, coupled with a large data base of industrial mill power draws, this situation was rectified by the end of the century, by which time a model had been developed and validated, which accurately predicted the power draw of all wet tumbling mills. This paper describes this model and reviews some of the earlier attempts at mill power modelling.INTRODUCTIONThe early 1900?s saw the beginnings of published papers which tackled the problem of what influenced the power draw of tumbling mills and what equations (models) were suitable for predicting power draw. This interest continued for the rest of the 20th century and the literature contains many papers that attempted to satisfactorily answer these questions. A common and disappointing theme in the majority of them, however, is the distinct lack of suitable experimentally derived power draw data. This deficiency consequently limited the practical application of many of the attempts at modelling mill power draw. Prior to the early 1990?s some limited data on the power draw of grinding mills in the literature can be found, but as Harris et al (1985) remarked they are ?... too frequently unusable simply because one or more essential variables have been omitted?. The absence of published results, from vigorous experimental testing of the various models, has resulted in a general lack of evaluation of the validity of assumptions and hypotheses that such models contain. Harris et al (1985) however, did make some efforts in attempting to evaluate the performance of various power prediction equations and in so doing further developed a semi-empirical one of their own. However, in using manufacturers? published data, which themselves were undoubtedly generated by proprietary equations of unproven validity, they probably succeeded in generating little more than a consensus of the various errors in these models."

Jan 1, 2003

By Carlos de F. Gontijo

The flotation of quartz particles was studied over the particle size range from 0.5 µm to 1000 µm and for advancing water contact angles between 0º and 83º. Flotation was performed in a column and in a Rushton turbine cell. Particle contact angle threshold values, below which the particles could not be floated, were identified for the particle size range 0.5~1000 µm, under different hydrodynamic conditions. The flotation response of the particles, either in a column or in a mechanically agitated cell with a similar bubble size, was comparable. Turbulence plays a role, as does bubble-particle aggregate velocity and bubble size. The stability of the bubble-particle aggregate controls the maximum floatable particle size of coarse particles. For fine particles, the flotation limit is dictated by the energy required to rupture the intervening liquid film between the particle and bubble. Flotation of very fine and large particles is facilitated with small bubbles and high contact angles. These results greatly extend our earlier observations and theoretical predictions.

Jan 1, 2014

The ore studied occurred in the Three Rivers area in China and was a silver-lead-zinc complex ore containing 400.52 g/t silver, 4.77 % lead and 3.47 % zinc. Silver, lead and zinc were the major valuable elements in the ore and copper, cadmium and tin were the associated elements to be comprehensively recovered, whereas arsenic was the harmful element. The element silver occurred mainly in freibergite with small proportion in dyscrasite and other silver minerals. The carrier minerals for silver were mainly galena and oxidized lead minerals and then sphalerite, arsenopyrite and pyrite. The ore contained numerous minerals with complex mosaic texture and the lead and zinc minerals enclosed each other multiply, which made the separation of the minerals in the ore very difficult. Experimental investigation on the beneficiation of the ore indicated that with flotation separation process it was very hard to obtain single lead concentrate or single zinc concentrate that would meet the requirement of market. In the meantime, during the separation process of lead and zinc, silver tended to be dispersed, resulting in a low recovery of silver. Therefore, a rational utilization technique for the ore should be a combined process of bulk flotation to reduce arsenic? sulphating roasting of silver-lead-zinc bulk concentrate-leaching with diluted sulphuric acid to separate silver, lead and zinc. With this process quality lead concentrate containing silver and high grade zinc product and silver product could be obtained. The recovery of silver, lead and zinc in flotation was 85.10%, 84.48% and 82.48%, respectively. The total recovery of silver, lead and zinc in chemical processing was 97.07%(sum of recovery of silver ingot and lead concentrate), 99.61% and 90.93%, respectively.

Jan 1, 2014

By J. Kolacz

A new optical sorting system based on a complex image analysis and high definition imaging has been developed by Comex. The image analysis is based on high definition cameras of different types and advanced filtration tools for verification of waste particles. Different mineral properties are used to identify the processed material. The system is further combined with a high speed rejection mechanism based on FPGA technology and operating in real time conditions. This provides a minimal error when removing waste particles from the sorted material.

Jan 1, 2014

By Shailin Lalloo, Allan B. Nesbitt

A fluidised bed was exposed to high gravities by placing it in a centrifuge. The bed expansions were measured and compared with the bed expansions predicted by the Richardson-Zaki model (1954). The Richardson-Zaki model was found to predict effectively the fluidisation behaviour of defined particles in this increased gravity environment.

Jan 1, 2003

By Jim Petrie, Mary Stewart, Damien Giurco

This paper describes a generic approach to analysing the environmental and economic performance of a global mineral/metal value chain, with the express view of improving the quality of prospective decision-making within the industry in order to ensure more sustainable outcomes. The starting point for this analysis is the development of a global stocks flows and transformations model, for the metal of interest. Any aspect of the value chain, e.g. “metals refining, “goods manufacture”, “use and disposal”, can be assessed, either relative to other stages in the value chain, or in more detail by focusing on the technologies used within that stage. The use of this model as a decision support tool is explored here for the case of copper. Both primary and secondary production routes are enumerated, covering a range of processes, for seven distinct geographic regions round the globe. The value of the modelling approach is explored for different energy mixes. In particular, the case study examines the impact of increased recycling on the (re) distribution of global and regional environmental impacts for technologies-in-place in these different regions.

Jan 1, 2003

By Peter M. Solozhenkin

Considering the main idea of the paper, namely that the interaction energy of reagents serves as a criterion used for their selection, as well as due to their insufficient study, the authors have therefore considered studying the aspects of computer modelling and molecular dynamics of largely used collectors for the flotation of nonferrous and precious metal ores. Three-dimensional molecular models for sulphydric reagents have been created, studying as well the distribution of the partial charges on their atoms. It has been shown that the value of the partial charge on the phosphorus atom in diethyldithiophosphinate and diethylmonothiophosphinate is high positive. The value of the partial charge of the sulphur atom is negative, strengthening its bond with the metal cations from the mineral surface. The molecular orbitals for the sulphydric reagents have been created determining as well the energy of their level. The computer modelling key parameters have therefore been defined. The new reagents have been tested for gold, copper and rhenium ore flotation. Gold recovery has increased with 4.2 - 4.7 %, copper recovery with 3.3 % and rhenium recovery with 15.5 %. A number of new flotation reagents have been recommended, such as: diethyldithiophosphate, (C2H5)2NCH2CH2OC(S)SNa, (C4H9NH)2P (S)SNa and also (C2H5)2P(S)ONa and (C2H5)2 P(O)S Na. Keywords: flotation, molecular modeling, design, orbital?s

Sep 1, 2012

By Marco Le Roux, Martha Van Rensburg, Quentin Campbell

Fluidised bed drying is currently receiving much attention as a dewatering option during the beneficiation of fine (defined here as between 1 mm and 2 mm particles) coal. Apart from concerns about safety and combustion, the operating costs can be high if very high gas or air temperatures are used. The aim of this study was to investigate the removal of moisture from fine coal by using air at a lower temperature (25 - 55°C) within a controlled environment by lowering of the relative humidity of the air. It was firstly proven that fluidization has a major advantage over non-fluidized beds, with regards to drying rate and final moisture content. Hereafter several parameters that influence the dewatering rate and final moisture content were tested, from which it was concluded that the relative humidity of air acts as the largest driving force for dewatering. Parameters tested included relative humidity, temperature and coal composition. Energy balances showed a positive nett energy increase in the dried coal during combustion when related to the energy input during drying. In comparison with thermal drying technologies, fluidized bed drying was proven to be less energy intensive. It was therefore shown that this is a viable technology for the dewatering of fine coal.

Jan 1, 2014

By W. P. Roux

With depletion of higher grade iron ore reserves, and the need to process finer, lower grade material; there is a need to better understand the recovery efficiency of jigging process. The use of Positron Emission Particle Tracking (PEPT) was examined as a technique, to study the motion of particles inside a laboratory batch jig. PEPT is a noninvasive method that can provide three dimensional kinetic data of a particle during jigging. Particles with different densities and sizes were traced under the same jigging parameters, to obtain a data set that can be used for the development and verification of jigging models. From the results, detailed information on the stratification rate of a particle was obtained, with adequate resolution to see particle movement through an individual pulse. Detailed data of this nature is critical for the validation of CFD and DEM models. Keywords: positron emission particle tracking, jigging, jig models

Sep 1, 2012

By D. W. Fuerstenau

Understanding how cationic surfactants affect the interfacial behavior of quartz is important in mineral processing and environmental engineering. This paper presents the results of a study of the effect of the molecular structure of cationic surfactants on the interfacial behavior of finely ground natural quartz. Most of the experimental work involved the determination of zeta potentials and the stability of quartz suspensions. Some measurements of induction times and the flotation response of coarser particles are also included. How these surfactants affect interfacial behavior is discussed in terms of adsorption mechanisms. The molecular structure (number of hydrocarbon chains, type of ionic head group, number of ionic head groups on the molecule) of these reagents was found to significantly affect their surface activity.

Jan 1, 2014

By Hoon Lee

Laboratory tests were conducted to evaluate the breakage characteristics of pyrophyllite in a laboratory ball mill. In grinding tests, the breakage characteristics were analyzed using the mathematical kinetic models based on the two breakage functions; the specific rate of breakage and the primary breakage distribution. Two samples having similar chemical composition show identical values in specific rate of breakage. In comparison, there are different values of primary breakage distribution for each sample. The size distributions of the product with various grinding time are well described by the parameters from non-linear searching.

Sep 1, 2012

By Ranjeet K. Singh

Kelsey Centrifugal Jig was found to be promising for the beneficiation of fine coal particles. The present study was aimed at in-depth understanding of the separation features of Kelsey Jig through detailed experimentation. Beneficiation of fine coal of size 150 x 300 µm was studied in a laboratory Kelsey Jig. The thickness of the ragging bed is found to be an extremely crucial parameter apart from the other process parameters such as rotational speed and pulsation frequency. A constant pulp density (25% solids) of the feed slurry was maintained in the study. The feed rate was also kept constant at 50 kg/hr dry solids. Silica sand of size -1.68+0.85 mm was used as ragging material to avoid the pegging of internal screen having an opening of 425 µm. The rotational speed was found to have significant effect on the depth of the ragging bed and its porosity, which influenced the separation performance considerably. Pulsation was identified as the key factor in stratifying the coal bed and defining the misplacement as well as ragging bed porosity, which influenced the mass yield and quality of the products. Beneficiation studies were carried out with rotational speed varying between 900-1000 rpm while pulsation frequency was kept within 850-925 rpm. In a single pass through the Kelsey Jig 7-8% (absolute) reduction in the ash content of the feed material was observed at more than 55% mass yield. High rotational speed, moderate pulsation, and low ragging bed depth favored good cleaning. A high bed depth was found to facilitate rejection of high ash materials. It was established that Kelsey Jig is effective in fine coal cleaning though a controlled operation is required in order to achieve superior performance. Keywords: enhanced gravity separator, g-force, separation performance, ragging material, coal beneficiation

Sep 1, 2012

By Przybycien Krzysztof, Tumidajski Tadeusz

"Materials being the feed to mineral dressing plants are the mixture of ore minerals having different physicochemical properties among others, especially susceptibility on crumbling. During exploitation of material and their preparation to communition the big number of narrow classes comes into being and they have different properties. The determination of common communition laws of multicomponent (on account of size and mineralogy) materials leads to the estimation of mutual influence of narrow classes and their rates, taking into account their endurance and mineral density, on general ratios and their simultaneous crumbling.If we try to accept the grain membership to the certain component as the differing feature, we can write the balance equation as: ( ) ( ) S= = k i i i g x p f x1where: fi – density functions of one type distribution and of different statistical moments (characterising the homogeneous materials grinding), pi – “stirring” proportions of each components, S== k i i p 1 1 . From the point of verification view of detailed versions of this equation the inverse operation should be done: in the base of the components’ mixture grinding results and the results of components grinding the legitimacy of equation should be checked.The using of finished distribution mixtures’ theories to the grinding process analysis allows, first of all, to verify the assumption of grinding independence of individual feed components. Talking more generally it would lead to the comparison of grain size distributions, obtained by individual components grinding from the defined in the mixture distributions theory calculations. One of experimental and calculation results for artificial mixtures of galena and dolomite is presented on figure below (df means distribution function)"

Jan 1, 2003

By Z. Y. Ma, M. D. Liu, Z. Z. Liu, J. K. Zhou

"An optimization method of microwave assisted leaching of copper anode slime was proposed based on Taguchi method. The results showed that the solid-liquid ratio was the most important factor affecting SNR(signal noise ratio) of the copper, tellurium and selenium leaching efficiencies, and its contributions to the copper, tellurium and selenium leaching efficiencies were 58.34%, 55.54% and 60.74%, respectively. Solid-liquid ratio was a significant factor to SNR(copper, tellurium and selenium). Reaction period was a less significant factor to SNR(copper and tellurium) and concentration of sulphuric acid was a less significant factor to SNR(selenium) while microwave power was an non-significant factor, its contributions to the copper, tellurium and selenium efficiencies were 3.22%, 11.73% and 12.73%, respectively. The optimized parameters of the microwave assisted leaching of copper were as follow: microwave power of 500 W, reaction period of 10 min, solid-liquid ratio of 0.10 g·mL-1 and H2SO4 concentration of 1.0 mol·L-1. The optimized parameters of the microwave assisted leaching of tellurium and selenium were as follow: microwave power of 800 W, reaction period of 15 min, solid-liquid ratio of 0.10 g·mL-1 and H2SO4 concentration of 1.0 mol·L-1. The validation experiments under the optimized conditions has been carried out, the copper, tellurium and selenium leaching efficiencies were 98.66%, 84.32% and 64.54%, respectively. INTRODUCTION As important valuable by-products, copper anode slimes are collected from the bottom of the electrolytic bath in the electrolytic copper refining process(Kilic, 2013). The value of the anode slime is determined by the content of rare metals and precious metals(Liu, 2014). Generally, pretreatment of copper anode slime is the first stage of the whole process. The aim of the pretreatment process is to remove Cu, Te and Se etc and enrich the valuable metals. The methods of pretreatment process can be differentiated into: pyrometallurgical processing and hydrometallurgical processing(Amer, 2003). The hydrometallurgical processes are more promising compared to pyrometallurgical processes in terms of cost effectiveness, low energy consumption and environmental concerns(Ranjbar, 2014). However, the disadvantages of the hydrometallurgy process are evident, such as lengthy processing times and low efficiency. Therefore, it is necessary to develop a highly efficient and environmentally friendly pretreatment method."

Jan 1, 2018

By Ghislain Bournival, Cagri Emer, Seher Ata

"It is well known among flotation practitioners that the contact angle can be correlated with the amount of material recovered from feed by flotation. The contact angle of solids can easily be modified by the addition of a collector. However, some collectors also have frothing properties thus altering the solid and bubble surface properties simultaneously. To avoid this problem, a technique has previously been used in which silanol groups are attached to the surfaces of the particles, but this method has its own problems. In this work, silica particles with various surface hydrophobicities were prepared using an esterification process. By using alcohols with different hydrocarbon chain lengths, from 4 to 12 carbon atoms, surfaces with a wide range of contact angles could be prepared. The technique was used in the modification of silica particles that were tested in a fluidized bed flotation column, and a laboratory mechanical flotation cell. In parallel experiments, dodecylamine (DDA) was used as a collector. It was found that irrespective of the type of flotation machine and surface preparation method, there was a close correspondence between flotation recovery and the contact angle of the particles. The silanation process has known drawbacks relating to the presence of moisture during the reaction, and the stability of the silane coating after it is been prepared. Esterification does not suffer from these disadvantages. This work has shown that the esterification technique is a robust alternative method for preparing hydrophobic quartz surfaces."

Jan 1, 2014

By J. C. Wilmot

The chemistry of aqueous cyanide containing species in the presence of reduced sulfur sources was investigated. Reactions were studied as a function of time and tracked using novel analytical techniques developed for the analysis of the species of interest in the sample matrix. Species of interest in this work were ?free? cyanide, thiocyanate, cyanate, metallo-complexed cyanide, and various sulfur and sulfur-oxygen species. The studies were conducted under constant temperature conditions at pH values above 10.5 and in the absence of light in order to eliminate photochemically induced cyanide reaction effects. The reaction products of cyanide when in contact with pure sulfur, pyrite, pyrrhotite, sphalerite, and cinnabar are reported. These data combined with data for cop-per, arsenic and lead sulfides, which have been previously published, are used to predict the fate of cyanides in refractory gold ores containing sulfides. A mass balance on the cyanide reaction products was completed for all experiments. From these studies insight into the chemical relationships of cyanide, the specific metal sulfide, thiocyanate and cyanate have been gained. When looking at the results of the experiments, it was immediately apparent that even though the overall conversions of cyanide to thiocyanate were different, most of the samples exhibited a similar pattern of reactions. The recovery of cyanide in these experiments was better than we expected, averaging in most experiments to be over 90 percent. Based on this research, the formation of cyanate was probably the main route of loss. The pathway choice for the various minerals was also elucidated in these experiments. The competitive oxidation pathways that cyanide can take have been tracked for sufficient time to determine the ?final? fate of cyanide in a process. Initially, it was thought that the cyanate may be involved in a hydrolysis reaction to form ammo-nia and carbonate ion, but upon further inspection of the data, there was not the drop-off in total cyanide recovery that would manifest itself were this to happen. On the other hand, the hydrolysis of thiocyanate to cyanate and sulfate would require oxidizing conditions which did not exist in solution at the beginning of the experiment. If the solutions were to be sufficiently oxidizing in nature for this to happen, the initial amount of cyanide would have been converted to cyanate quickly. The data support premise that the ?hydrolysis? of thiocyanate to cyanate and sulfate occurs to some extent in the experiments conducted. Knowledge gained from the experiments with pure metal sulfides helped interpret the results of experiments with refractory ores found in the State of Nevada.

Jan 1, 2014

By James A. Finch, Xiangzhou Ding, Yue Hua Tan

"The Jameson Cell is one of the choices of flotation machine in coal, base metal processing and other specialist applications. This paper determines the effect on vacuum pressure and bubble size of two design variables, orifice size and downcomer length, and the operating variable air-to-water (AWR) ratio. The main findings are: orifice size and downcomer length impact the vacuum but have limited effect on bubble size; AWR < 1 favours high vacuum, conditions are identified where vacuum is maintained at AWR > 1, and water flowrate has slightly greater impact on bubble size than air flowrate.INTRODUCTIONFroth flotation, the most common technique for mineral separation, has been in use for over a century. The process takes advantage of the difference in wettability of mineral surfaces to achieve the separation of valuable minerals from non-valuable minerals, or gangue. Numerous flotation machines have been invented and patented over the years. The Jameson Cell, invented by Professor Graeme Jameson in the late 1980s, is one successful example. First trialed at Mount Isa Mines (Queensland, Australia), Jameson Cells have been installed at operations around the world for the recovery of fine coal (Mohanty and Honakeri, 1999; Cowburn et al., 2006; Hacifazlioglu and Toroglu, 2007; Uçurum 2009), minerals of copper (Farr 1992; Atkinson et al., 1993; Harbort et al., 1997), lead/zinc (Rohner, 1993; Munro, 2003) and gold (Bennett et al., 2012; Lauder et al., 2003), and in water treatment (Yan and Jameson, 2004), solvent extraction de-oiling (Miller and Readett, 1992; Miller et al., 1997; Harbort et al., 2003; Young et al., 2006), oil sands processing (Neiman et al., 2012), and various food industries (Brenneman, 2014). One of the largest units is the 650 cm diameter separation tank with 24 downcomers installed in an Anglo American operation (Osborne and Euston, 2015). Scale up is relatively straightforward: to increase capacity the number of downcomers is increased with corresponding increase in size of separation tank.The Jameson Cell comprises two main parts: a vertical tube (downcomer) which provides self-aspiration and intense bubble-particles contact, and a (separation) tank where particle-bubble aggregates disengage from the pulp. The intense bubble/slurry mixing in the downcomer with air holdups reaching 60% (Marchese et al., 1992) accelerates particle collection enabling the greatly reduced cell volume compared with mechanical flotation cells and columns. The disengagement of the particle-loaded bubbles from the slurry in the separation tank is usually aided by addition of washwater."

Jan 1, 2018