Flotation Research Papers - Academia.edu (original) (raw)

Copper is most commonly present in the Earth's crust as copper-iron-sulphide and copper sulphide minerals, for example, chalcopyrite (CuFeS2), bornite (Cu5FeS4) and chalcocite (Cu2S). In order to obtain metal from the copper minerals commonly found in the crust of this Earth, it must process through a number of metallurgical processes. One of the methods of enriching copper sulphide minerals is the flotation process. In the extraction of metals from their ores, the process of mineral flotation plays a most important role. Flotation provides the means of separating and concentrating the valuable components of an ore to produce a grade of mineral concentrate suitable for feeding to efficient pyrometallurgical or hydrometallurgical operations. The flotation process involves crushing the ore to liberate separate grains of the various valuable minerals and gangue components, pulping the ore particles with water, and then selectively rendering hydrophobic the surface of the mineral of interet. A stream of air bubbles is then passed through the pulp; the bubbles attach to and levivate the hydrophobic particles, which collect in a froth layer which flows over the weir of the flotation cell.

- by
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- Flotation, Mixing, Chemical Reactors, Flotation Columns, Froth Flotation

This paper presents a novel simulation concept for operator training in the field of mineral processing. The simulations are carried out with a dynamic process simulator HSC Sim ® of HSC Chemistry ® developed by Outotec Research Oy. The simulator is fitted to mimic an existing copper flotation circuit as accurately as possible by using metallurgical models and then integrated into a larger simulation environment, providing the operator trainees a realistic experience of the process. The simulation environment is designed to be scalable and very flexible, allowing many different usage scenarios and thus aiding in the transfer of the tacit knowledge from operator generation to the next. Concurrent work is being done on higher level analysis, utilizing the results reported in this paper.

- by Pertti Lamberg
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- Mineral Processing, Flotation, Operator training, Froth Flotation

- by Timo Roine
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- Mineral Processing, Flotation, Operator training, Froth Flotation

Inverse gas chromatography (IGC) is a versatile and powerful technique for characterizing physicochemical
properties of materials. One such property, the surface energy, plays an important role in the adhesiveness,
wettability, and consequently flotation of minerals. In this work, quartz was chosen as a
naturally hydrophilic mineral, and dodecylamine was used to hydrophobise the surface. To study the correlation
between the surface properties as measured from IGC experiments and flotation, microflotation
experiments were also conducted. It was shown that with treatment by dodecylamine, the surface energy
decreased, as did the work of adhesion to water. The recovery of quartz increased after the treatment,
indicating a correlation between surface energy and flotation response.
The results indicate that IGC has the capability to determine the thermodynamic properties of quartz,
pre- and post-conditioning. Relating the hydrophobicity and flotation of minerals to the surface energy
can be observed from combining the results of IGC and microflotation experiments.

- by Kristian Waters and +1
- •
- Materials Characterisation, Mineral Processing, Flotation, Quartz

TAŞKÖMÜRÜ FLOTASYONUNDA SU SICAKLIĞININ ETKİSİ Faruk TUNÇYÜZ Bitirme Tezi Ocak 2016 1924 yılında ksantatların da (toplayıcı) bulunuşuyla, bu yıllara kadar sadece yağ kullanarak sülfürlü minerallerin yüzdürülmesinden öteye gidemeyen... more

- by Faruk Tunçyüz
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- Flotation, Temperature, Yüzey Gerilimi

A technique was developed to study the effect of surfactant (frother) on individual bubble motion in swarms. The technique was based on high speed cinematography and tracking of multiple moving objects. Image processing algorithms were implemented in Matlab to isolate and measure geometric properties of the bubbles in image sequences recorded at 1 ms interval; and these properties were compiled into a data structure. To track a bubble, the geometric properties and a matching criterion were applied on consecutive pictures to identify the bubble. The bubble I wish to express my gratitude and appreciation to Professor J.A. Finch for his invaluable guidance, constant encouragement and unconditional support.

- by Claudio Acuna Perez
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- Flotation
- by А' Халиунаа
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- Flotation

Bu çalışmada, cevher Hazırlamada zeta potansiyelinin saçmalığı ve endüstriyel ölçekteki tutarsızlığı ele alınmıştır. Sülfürlü minerallerin hemen hemen hepsi negatif zeta vermekte ve ksantat denilen anyonik kollektörlerle yüzdürülmektedir. Diğer taraftan, negatif yüklü şlamların flokülasyonu da anyonik flokülantlarla yapılmaktadır. Örnekler çoğaltılabilir. Zeta potansiyeli cevher hazırlamada yanıltıcıdır.

- by Prof. Dr. HASAN HACIFAZLIOĞLU
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- Flotation, Froth Flotation, Pax, Kömür

Current world nickel market depends on production from lateritic ores. However, processing of laterite is challenging due to several factors.
This work has been done to investigate possible pre-concentration methods for lateritic ore from New Caledonia.
The best method to enrich the laterite ore is found to be hydrocycloning after grinding and then flotation of underflow after further grinding. With this method 60% of Ni is recovered with 3.3% Ni grade in concentration and 1.3% Ni grade in tailings.

- by Noyan Palabıyık
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- Mineral Processing, Flotation, Nickel Laterite Ore Processing
- by Khmer Lee Lugod
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- Environmental Engineering, Metallurgical Engineering, Chemistry, Arsenic

Since 1973, a long-term, variable-scale, multi-disciplinary program of archaeological research has been conducted in the Crawford Lake area, above and below the Niagara Escarpment, north of Lake Ontario in southern Ontario, Canada. This study in settlement archaeology has revealed an intensive and complex occupation of the area by Ontario Iroquoian peoples between approximately A.D. 1000 and 1650. These Iroquoians were slash-and-burn horticulturalists, who grew corn, beans, squash, sunflower and tobacco, and who also hunted, fished and gathered. They lived in villages of longhouses often surrounded by palisades. The Niagara Escarpment is the most prominent geological feature of the local landscape, and it served as a frontier area between the two major confederacies of Iroquoians, the Huron and Neutral. J.V. Wright’s Ontario Iroquois Tradition (1966) is adopted as the cultural-historical model best suited to the study, and is refined with the definition of Early and Late Pickering substages of the Early Ontario Iroquois stage and the proposal that Glen Meyer peoples were ‘proto-Algonquians’, not ‘proto-Iroquoians’.
This study has revealed that the Crawford Lake area was initially occupied by ‘proto-Huron’ Pickering, Uren and Middleport peoples. During the occupation by these ‘proto-Huron’ Middleport peoples, several communities of ‘proto-Neutral’ Middleport peoples moved into the area from the west and evolved into the prehistoric and historic Neutral peoples documented by French missionaries in the early 17th century. The fate of the ‘proto-Huron’ Middleport people remains unknown; four hypotheses are presented as possible explanations.
Using data on phases of forest clearance and non-clearance inferred from the palynological study of the varved sediments of Crawford Lake by Roger Bryne, the chronology of the Ontario Iroquois Tradition has been refined. It is proposed that the Early Pickering substage of the Ontario Iroquois stage dates from A.D. 1030 to 1180; the Late Pickering substage from A.D. 1180 to 1330; the Uren substage of the Middle Ontario Iroquois stage from A.D. 1330 to 1420; the Middleport substage of the Middle Ontario Iroquois stage from A.D. 1420 to 1504; and the prehistoric Neutral division of the Late Ontario Iroquois stage from A.D. 1504 to 1550. This fine-grained chronology suggests that the Middleport substage lasts considerably longer and ends later than previously thought, while the prehistoric Neutral division starts and ends earlier than current interpretations based on course-grained C-14 dates.
Using this chronology, the culture history of the Crawford Lake area is presented, including new data in support of J.V. Wright’s (1992) Conquest Theory in which Pickering peoples of southeastern Ontario conquered the Glen Meyer people of southwestern Ontario in the early 14th century. This conquest was possible due to the formation of militaristic confederacies by Early Pickering substage people in the 12th century which resulted in very large villages on the western frontier. After the conquest, the frontier moved west and with the threat of imminent attach lessened, the Uren peoples no longer had to live in palisaded villages.
One of the most important contributions of the study is the presentation of evidence that Middleport peoples in these frontier communities made their tools, articles for personal adornment and motifs on ceramics as badges of their identity. Characteristics of the Crawford Lake locality ‘proto-Huron’ Middleport sites include: pottery vessels with high frequencies of lip and interior decoration ; high collared vessels with an average of 11 relatively narrow horizontal lines of decoration; ceramic pipes with elaborated decoration comprised of squares and rhomboids filled with parallel incised lines; modified deer phalanges with the proximal end cut off to expose the marrow cavity; and projectile points which are predominantly triangular. By way of contrast , the ‘proto-Neutral’ Middleport sites of the Mountsberg and Kelso localities are characterized by very low frequencies of lip and interior decoration, high collared vessels with an average of eight rows of relatively wide horizontal lines, ceramic pipes with flaring bowls; modified deer phalanges with distal ends perforated; a variety of bone projectile points and projectile points for the Mountsberg locality, which are predominantly side-notched. Further, there are sufficient differences amongst contemporaneous “proto-Neutral’ Middleport communities which assist in their definition.
The data gathered in this four-volume study are used to test a model developed from ethnographic data on the Yanomamo, a society of slash-and-burn horticulturalists in Brazil and Venezuela, and from the ethnohistorical data for the Huron to explain interactions amongst these contemporaneous Middleport settlements in the Crawford Lake area. Current evidence suggests that alliance formation and maintenance were the key factors in the changes which these societies and their material culture underwent.
The study concludes with a retrospect on the results of the first 25 years of research with suggested directions for research in the 21st century.

Misreported pyrite into copper concentrates dramatically declines copper grade and recovery. Copper flotation can be also more complicated if flotation feed comes from an elevated-pyritic copper ore. In this investigation, the effect of two different ore types (high pyritic and low pyritic feeds) was studied on rougher stage of industrial copper flotation circuit. Samples were taken from different streams and the structure of chalcopyrite within the pyrite and non-sulfide gangue minerals was examined in various size fractions for mentioned ore types. Results indicated that 72% and 56% of the total floated pyrite was transferred to concentrate in first four cells in the low and high pyritic feeds, respectively. Whereas, this proportion for floated SiO 2 in last ten cells was detected as 72% and 71%, respectively. A detailed interpretation of the effect of locked particles in different size fractions on rougher flotation cells is studied from industrial point of view.

- by Ahmad Hassanzadeh
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- Flotation, Pyrite, Froth Flotation

The chemistry of pyrrhotite flotation using xanthate collectors is reviewed with respect to the processing of PGM ores and the recent results from captive bubble contact angle measurements at the University of Utah are presented. In some cases a low flotation recovery of PGM may be due to the surface state of pyrrhotite particles under conventional flotation conditions (open to air and pH 9.0). Thermodynamically pyrrhotite is not stable and reacts relatively quickly with its environment. Natural/collectorless flotation of pyrrhotite is observed only under a low oxidation potential in acidic solution. Its surface is easily oxidized to ferric hydroxide/oxide under conventional flotation conditions, creating a hydrophilic state at the pyrrhotite surface and low flotation recovery even though xanthate collectors can be adsorbed. Under these conditions, activation by copper is not easily achieved. These observations reported in the literature have been confirmed by captive bubble contact angle measurements. Based on the analysis of previous research, conditions for improved pyrrhotite flotation and increased PGM recovery are suggested.

- by Francois Vos and +1
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- Flotation, Platinum Group Minerals, Pyrrhotite, Xanthate

The effectiveness and efficacy of flotation diminishes with the size of the particles. However, the kaolin industry is unique in successfully using flotation with fine particle size feed. Kaolin is valued as a white pigment and therefore the goal in kaolin flotation circuits is to remove the colored impurities to result in an acceptable brightness product. Kaolin flotation originated with a novel carrier flotation process and later on carrierless flotation techniques were developed. The surfactants that are utilized to impart selectivity are based on fatty acids. The purpose of this paper is to provide a comprehensive review of the reagent schemes used in the kaolin industry, the understanding of which has been significantly aided by research work conducted in Prof. Somasundaran's lab. C 2002 Elsevier Science (USA)

- by Hazrat Bilal
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- Titanium, Flotation, Oleic Acid, Kaolin

Resumo A flotação é um processo mecânico de separação de particulados sólidos que explora principalmente a propriedade de hidrofobia. A coluna de flotação é um equipamento dinâmico de seção circular ou retangular com altura mais desenvolvida que o diâmetro, ela pode ser dividida em regiões distintas com características especificas, são elas: zona de coleta e zona de limpeza. As variáveis envolvidas no processo são manipulas ou controladas e os instrumentos escolhidos estão diretamente relacionados com o comportamento dessas variáveis. Para ser efetuada a escolha dos instrumentos, levou-se em conta a perda de carga, as condições do processo -pH, custo e manutenção. Os instrumentos em questão são: medidor eletromagnético de vazão, medidor de nível ultrassônico, placa de orifício e transmissor de pressão capacitivo. Palavraschave: Flotação, separação, instrumentos.

- by Grasiela Otto and +1
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- Separation, Flotation, Instruments

The effect of surface roughness and shape factor on behavior of particles in flotation has been investigated. Surface roughness of various degrees was applied on spherical glass beads of -150 +106 µm by means of acid etching. The same procedure was also performed on ground glass beads of the same size interval with different shape factors. The effect of these variations on surface morphology of particles was investigated in terms of flotation recovery, contact angle, and bubble-particle attachment. An Atomic Force Microscope (AFM) was used for surface roughness characterizations and a correction methodology on roughness measurements of spherical particles is proposed. A digital image analyzer was used for shape factor characterizations. It is shown that increase in surface roughness improves the flotation recovery, contact angle, and bubble attachment. Shape factor, however, was found to be more predominant in flotation and bubble attachment. This is attributed to the effect of sharp edges of ground particles which triggers the film rupture process and shortens the attachment time.

- by Hidayet Çalişkan and +3
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- Surface Science, Colloids and Surfaces, Flotation, Atomic Force Microscopy

The flotation beneficiation of phosphate ore is increasingly facing challenges, especially for finely disseminated sedimentary ores rich in carbonates. This study aims to optimize and assess the impact of key hydrodynamic parameters including pulp density, air flowrate and impeller speed on flotation and metallurgical responses (i.e. grade, recovery, flotation rate constant and selectivity index (SI)). We carried out locked cycle flotation tests using the best conditions from the rougher flotation test to generate an experimental simulation of a continuous circuit. The mineralogical and chemical properties were characterized by mineral liberation analysis (MLA) and inductively coupled plasma optical emission spectroscopy (ICP-OES) techniques, respectively. A modified-McGill bubble size viewer was used for measuring bubble sizes and evaluating the interaction between hydrodynamic factors and bubble diameters. Finally, the design of experiment (DOE) method was applied to determine the relative intensity of the studied factors. It was found that under optimal conditions with the targets of high recovery and maximum SI, the final apatite concentrate achieved a recovery of 86.3% at a grade of 35.5%, while the MgO content was 1.2% and 84.3% of dolomite was removed from a feed ore containing about 25% P 2 O 5 , 4.6% MgO, and 41% CaO. Furthermore, another locked cycle flotation test showed that a 0.82% MgO content in the final apatite concentrate can be achieved with an apatite recovery of 75.6% at a P 2 O 5 grade of 36.76%, and a ratio CaO/P 2 O 5 = 1.33. The obtained concentrate in this investigation under the optimum conditions is the highest in both apatite recovery and grade with low MgO content reported in the literature.

- by Ahmad Hassanzadeh
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- Kinetics, Design of Experiments, Mineral Processing, Flotation

Este trabajo de investigación tiene por objeto dar a conocer el flow sheet, balance de materiales, planteo de ecuaciones y desarrollo de modelos matemáticos que nos permitirán predecir resultados finales tales como: leyes, recuperaciones y radio de concentración que un mineral reportará cuando sea procesado por flotación a escala industrial con información obtenida de pruebas batch a nivel de laboratorio, método que se puede aplicar a una amplia variedad de minerales y poder evaluarlos técnica y económicamente con un alto nivel de confianza.

- by Santiago Tuesta
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- Flotation

Despite flotation kinetic modeling is well discussed in the literature, its evaluation from overfitting, the number of model parameters and model complexities have not been adequately addressed. Flotation kinetic behavior of two deposits including an elevated-pyritic (Cu/S ¼ 0.21) complex copper sulfide ore and a high-grade carbonaceous sedimentary apatite (P 2 O 5 ! 25%) ore were investigated. The flotation kinetic experiments were carried out in a mechanically agitated batch flotation cell. Different flotation kinetic models including seven common empirical and initially four mathematical models were applied to the experimental data. In addition to assessment of the goodness of fit (GOF) for each model, a factor of model complexity was considered using advanced statistical techniques (i.e. Bayesian information (BIC), low of iterated logarithm (LILC) and Akaike information (AIC) indices). The results confirmed that flotation kinetic modeling significantly depends on the feed type. The empirical models were found more sensitive than the mathematical ones to the ore properties and the mineral types. Furthermore, the mathematical models demonstrated relatively favorable results than the practical models concerning the variation of ore properties due to the consideration of more parameters in the modeling. Finally, it was concluded that the IC indices must be applied to the process of model selection owing to consideration of GOF, the complexity of a model and model consistency. The IC was introduced as a more reliable indicator than the common regression approach for evaluating, sequential ordering and selecting the suitable flotation kinetic models. Further studies are required for model's generalizability from a statistical point of view.

- by Ahmad Hassanzadeh
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- Statistics, Kinetics, Modeling, Flotation

Inverse gas chromatography (IGC) is a powerful technique for characterizing the physicochemical properties of a wide variety of materials. The behaviour of minerals in the flotation process is directly related to their wettability, which can be described by surface free energy. In this work, the adsorption of copper and xanthate on hydrophilic pyrite, prepared under different conditions, was studied using X-ray photo-electron spectroscopy (XPS) and IGC. Microflotation experiments were also conducted to determine flota-tion recovery. The XPS analyses confirmed the presence of copper (I) and xanthate compounds on the surface of treated samples. The surface energy and work of adhesion to water decreased, while the flota-tion recovery increased due to treatment. IGC has been shown to have the capability of characterizing mineral surfaces, pre-and post-treatment. It enabled the observation of the changes in physicochemical properties of pyrite surface due to surface modification at different conditions. Moreover, combining the microflotation recovery of the samples with IGC results confirmed the correlation between surface energy and flotation response.

In this study in order to gain high purity quartz from flint stone tailings, floatation method is used to remove coloring minerals and feldspar from the ore content. By means of mineralogical investigations the liberation size of quartz is determined as -63 µm. In order to reach the adequate liberation size, tailings are ground and required grinding parameters are optimized. To gain high efficiency from the tailings by using flotation method; the important flotation variables such as pH of the media, collector, suppressor and frother amounts with the stirring rate, froth depth and solid concentration are optimized. Flint stone tailing with SiO2 tenor 94.1% is subjected to feldspar-quartz cationic collector reverse-flotation at pH 2.5, a concentrate with 97.7% SiO2 tenor at 96.46% recovery efficiency is obtained.

- by Eyüp SABAH and +1
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- Waste Management, Flotation, Flint Mining, Froth Flotation

The experience of developing, implementing and evaluating a hierarchical control strategy in a flotation column circuit at Salvador is discussed. The supervisory control system was installed in two columns in the copper cleaning circuit.... more

- by Claudio Acuna Perez
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- Control Systems Engineering, Expert Systems, Flotation, Froth Flotation

A feature of electroflotation is the ability to create very fine bubbles, which are known to improve flotation performance of fine particles. This study was aimed at determining the hydrogen bubble size generated as a function of current density and electrode geometry. Experiments were performed in a viewing cell that allowed direct visualization of hydrogen bubbles being generated and transported away from platinum wire electrodes of 90, 120 and 190 lm in diameter. The detached bubble diameters varied between 15 and 23 lm in diameter, and for each wire diameter, were little influenced by the applied current in the range 150-350 A/m 2 . The measurements were consistent with those predicted from a simple force balance analysis based on a H 2 -Pt-0.2M Na 2 SO 4 contact angle of 0.18°. Interestingly, upon detachment, the bubble size increased rapidly, recording up to an 8-fold increase in volume in the first few millimeters of rise, before approaching the steady state diameter of between 30 and 50 lm in the bulk. This increase in bubble size was found to be mostly due to the transfer of dissolve hydrogen into growing bubble while moving through the electrolyte super saturated by dissolved hydrogen gas. The equilibrium bulk diameter was found to be a function of the rate of hydrogen production, bubble nucleation rate, and dissolved gas concentration field. Consequently, electroflotation cells need to be designed to optimise the contact between the supersaturated liquid and the rising bubble plume. By doing this, the volumetric flux of bubbles will be maximised leading to improved flotation performance.

- by Geoffrey Evans
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- Chemical Engineering, Water Treatment, Wastewater Treatment, Mineral Processing

O objetivo deste estudo é apresentar a construção de uma coluna de flotação piloto de baixo custo, que será utilizada para concentração de minerais ferrosos. O trabalho contém os passos seguidos no projeto de construção do equipamento (descrição dos sistemas operacionais; dimensionamento; desenhos do projeto; levantamento dos materiais, fornecedores e orçamentos; testes dos sistemas de aeração e bombeamento, além da montagem) e também, os resultados dos ensaios exploratórios realizados com uma amostra de minério de ferro, contendo 38% de Fe, doada pela Companhia Vale S. A. proveniente da Mina de Alegria, Mariana/MG. Nos ensaios preliminares, obtiveram-se teores de Fe no concentrado próximos a 50% e uma recuperação metalúrgica em torno de 90%. O resultado foi considerado adequado, tendo em vista que foi realizado apenas um estágio de concentração. Dessa forma, conclui-se que a montagem e operação da coluna foram satisfatórias e o protótipo pode ser utilizado como unidade piloto para a avaliação de diferentes condições de processo.

- by Daniela Horta and +3
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- Mining Engineering, Mineral Processing, Flotation, Flotação

The enrichment of the low-grade-phosphate ore of the Tozeur-Nefta deposit was investigated using scrubbing-attrition, ball grinding and anionic/cationic reverse flotation in order to separate phosphate-rich particles from their gangue. The choice of the beneficiation process was based on the petrographic, mineralogical and chemical analyses. The petrographic and mineralogical studies have revealed the abundance of phosphatic (carbonate-fluorapatite-CFA) particles) coupled with carbonates (calcite, dolomite,) and silicates (quartz, illite, kaolonite) that constitute the (endo/exo) gangue of these ores. Chemical analysis has demonstrated that the raw phosphate sample contains low amounts of P 2 O 5 (12.0%) and MgO (4.9%) and high amounts of CaO (40.7%) and SiO 2 (20.5%). Microscopic observation/counting has shown that the release mesh occurs in the 71-315 µm size. Scrubbing-attrition, grinding and reverse flotation methods were applied to the +71µm fraction. Scrubbing-attrition tests of the 71-315 µm fraction have helped to improve the P 2 O 5 grade to 15.5%. Ball-grinding tests were used to reduce the coarse fraction +315 µm. Grounded materials were sieved to 71-315 µm and combined with the scrubbed fraction in the flotation feed. Reverse-flotation tests of the phosphate-rich fraction (71-315 µm) have helped to improve the P 2 O 5 grade to 27.1%, with a recovery rate of 92.4%.

- by Ghassen Daldoul and +1
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- Mineral Processing, Petrology and Geochemistry, Flotation, Ore deposits

The aim of this work is to investigate the effect of some operating variables and particle size on the Jameson cell performance. This is done by investigating the effect of varying different parameters such as concentrate flow rate and immersion depth of the downcomer for separation tank recovery, while jet length, jet velocity and holdup within the downcomer are used for downcomer recovery. It was found that altering these parameters play a significant role in recovery of different sized particles. An increase in concentrate flow rate and a decrease in immersion depth result in much more improving effect on recovery as particle size increases. An increase in jet length, jet velocity and holdup results in the recovery improvement for fine particles and loss of recovery for medium/coarse particles.

- by Tuba Taşdemir
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- Flotation

Operators of industrial flotation circuits experience every now and then situations where the processing performance of the plant is poorer than expected. Usually this leads to a continual and useless debate whether the problems are related to the ore properties or to the process. This paper presents a systematic approach to problem diagnosis using an analysis method based on process mineralogical tools. The diagnosis first requires a base-case analysis where the key process streams of the circuit have been sampled and studied by applying mineral process simulation in combination with the particle tracking technique, i.e. by balancing mixed particles of different mineral composition. This creates the base model of the flotation process against which the deviations are compared. Common performance problems are divided in three groups, which refer to recovery, grade and impurity. The mineralogical reason can in each case be a change in (i) mineral assemblage, (ii) head grade, (iii) liberation degree, or (iv) mineral associations. The diagnosis progresses by classifying the indications and by ruling out causes by means of process mineralogical methods. The procedure is presented as a diagnosis chart with suggestions for how to cure the problem. To illustrate the application of the method several practical examples are presented.

- by Pertti Lamberg
- •
- Mineral Processing, Flotation, Process Mineralogy

Unmanned free vehicles, using kerosene-filled envelopes for lift, have been used since the late 1930's to deliver scientific instruments and samplers to the seafloor. Recent advances in glass spherical housings have provided a costeffective option for operations into ocean trenches. During his 2012 DEEPSEA CHALLENGER Expedition, Explorer James Cameron pushed the design limits with both manned submersible and unmanned lander designs.

- by Kevin Hardy
- •
- Ocean Engineering, Acoustic Communication, Imaging, Flotation

Construction on peat deposits represents a major challenge for the geotechnical community. Waterlogged peat deposits have great potential for buoyancy generation. The premise of the present investigation is that this can be beneficially incorporated in foundation design practice, thereby reducing the net bearing pressure and hence resulting settlements. A novel foundation system, comprising a bamboo frame (BF) structure incorporating recycled plastic block (RPB) inclusions, is presented for supporting lightweight structures bearing on peaty ground. The buoyancy effect is produced by the lower bulk density of the foundation construction materials combined with the waterlogged condition of the peat deposit. A programme of reduced-scale 1g physical modelling was conducted to investigate the performance of BF- and BF–RPB-type footing bearing on remoulded peat with different water content and fibre content (FC) values. The mobilised undrained bearing capacity (qf) increased for lower-watercontent and higher-FC peat materials. Deeper BF footings and the inclusion of the RPBs within their cavities significantly improved the mobilised qf value. Advantages of the presented foundation system over conventional solutions for peaty ground include its simple technology, reduced earthworks in construction, reduced settlement due to the buoyancy contribution and being more sustainable and economically viable.

TAhBeS TefRfeActCivTe concentration of typical banded iron formations ores by flotation requires
intense and continuous work, in virtue of their complex mineralogy. In this project the
flotation system (using the Hallimond tube) has been studied and quartz and hematite
floatability was tested, in the values of pH 4.0, 6.0, 7.0, 8.0, 10.0 and 11.5. These alternative
reagents were employed: sodium oleate, linear sodium sulfonate, and EDA (monoamine ether
partially neutralized with ethanoic acid). The system with sodium oleate, as expected, showed
good floatability for hematite around pH 8.0, having an appreciable difference in values of
floatability (in comparison to quartz) just in this range. In the amine system, the trend curve
has been rather evidenced with a dose of 5 mg/liter, showing greater floatability in the pH
range between 8 and 10, as is to be expected.

- by John Baeten
- •
- Industrial Archaeology, Flotation, Copper extraction and production, Michigan History

The present study aims to investigate possibilities for improving the recovery of pyrochlore ((Na, Ca) Nb O) and monazite ((Ce, La, Th, Sm)PO4) as by-products from a phosphate mine with current niobium (Nb) production from geometallurgical perspectives. With this purpose, process mineralogy of Nb-and REE-bearing minerals together with operating properties of the concentration plant are examined module. A plant-site sampling campaign was performed and key operating parameters such as throughputs and pulp densities for individual streams were measured. The results obtained by MLA analyses as the base of mineral mass balances were compared and validated by commonly used chemical characterization techniques i.e. X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma optical emission spectroscopy (ICP-OES). Simulation results showed that the combination of Nb flotation rougher and scavenger cells into one single rougher bank plus the addition circ recovery from 27% to 38% leading to a substantial enhancement in final concentrate throughput from 540 to 740 kg/h. Future studies on this topic include the use of wet high intensity magnetic separation (WHIMS) and froth flotation respectively for the pre-concentration and concentration of monazite.

- by Ahmad Hassanzadeh
- •
- Mineralogy, Flotation, Rare Earth Elements, Pyrochlores

- by Grasiela Otto and +1
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- Separation, Flotation, Instruments

Nifedipine is a calcium channel blocker of the dihydropyridine type, mainly used for the treatment of hypertension and angina pectoris. Nifedipine is a suitable candidate for Controlled Release administration due to its short elimination... more

- by American Journal of Advanced Drug Delivery (AJADD)
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- Pharmacology, Chemistry, Pharmacy, Flotation

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- by Amalia Sabanov and +2
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- Flotation, Neolithic of the Balkans, North Macedonia
- by Jigar Shah
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- Environmental Engineering, Chemical Engineering, Biodiesel, Filtration

Froth flotation is the most widely used technique for the separation of valuable minerals from gangue ones. Changeable nature of feed, interaction of variables and weakness of accurate measurement equipment have made the development of monitoring methods and continues control of flotation circuits to an important issue. Today with the advance of technology, machine vision systems based on image processing methods are considered a rapid, cheap and safe detection device in mineral processing industries. The appearance of flotation froth surface consists of significant information process which easily distinguishes the process operation condition. Size distribution of froth bubbles is the reflection of froth stability and velocity and is the best criterion for the efficiency estimation of flotation operation. This paper is the updated review of the most common methods of size estimation of flotation froth bubbles along with their benefits and shortcomings and ideas for future studies in this area. Likewise, the correlation between concentrate grade and recovery with the froth bubble size is investigated.

- by Soft Computing Journal (SCJ)
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- Image Processing, Flotation

The pre-concentration consists on the previous discard of a fraction of the mineral processing plant feed with few or none quantity of the mineral of interest, reducing the mass to be processed in the downstream operations, as well the capital and operational costs. In this context, this study aims to verify the susceptibility of the silicate zinc ore from Votorantim Metais, Vazante/MG (Brazil), for pre-concentration by density and magnetic methods. For this purpose, tests have been developed in a magnetic roll separator operating under high field (10,000 gauss) and also on sink/float in dense liquids varying between 2.75 to 2.95 g/cm³ and in coarse particle size: + 6,35, - 6,35 + 3,35 e -3,35 + 1,18 mm. The former results show the possibility to discard more than 50% of the plant mass and zinc metallurgical recoveries above 90%. It also shows that the discard of contaminants, as MgO, can achieve 80%. The results for the magnetic separation have not been meaningful in comparison with the density separation.

- by Dimas Neto and +1
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- Mineral Processing, Flotation, Modelling of flotation recovery, Metal Grinding

Recently, it was reported that using CO 2 as a flotation gas increases the flotation of auriferous pyrite from high carbonate gold ores of the Carlin Trend. In this regard, the influence of CO 2 on bubble attachment at fresh pyrite surfaces was measured in the absence of collector using an induction timer, and it was found that nitrogen bubble attachment time was significantly reduced from 30 ms to less than 10 ms in CO 2 saturated solutions. Details of CO 2 bubble attachment at a fresh pyrite surface have been examined by atomic force microscopy (AFM) measurements and molecular dynamics (MD) simulations, and the results used to describe the subsequent attachment of a N 2 bubble. As found from MD simulations, unlike the attached N 2 bubble, which is stable and has a contact angle of about 90°, the CO 2 bubble attaches, and spreads, wetting the fresh pyrite surface and forming a multilayer of CO 2 molecules, corresponding to a contact angle of almost 180°. These MDS results are complemented by in situ AFM images, which show that, after attachment, CO 2 nano-/microbubbles spread to form pancake bubbles at the fresh pyrite surface. In summary, it seems that CO 2 bubbles have a propensity to spread, and whether CO 2 exists as layers of CO 2 molecules (gas pancakes) or as nano-/microbubbles, their presence at the fresh pyrite surface subsequently facilitates film rupture and attachment of millimeter N 2 bubbles and, in this way, improves the flotation of pyrite.

- by Behzad Vaziri Hassas
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- Flotation, AFM, Micro and Nanobubbles, Bubble Attachment

A novel synthesized reagent, O,O-bis(2,3-dihydroxypropyl) dithiophosphate (DHDTP), was investigated as depressant on the depression of chalcopyrite and galena, when ammonium dibutyl dithiophosphate (DDTP) was used as the collector in flotation tests. Zeta potential and adsorption measurement were performed to study the interaction between depressant and minerals. The flotation tests of two minerals show that DHDTP has slight depression on chalcopyrite in the whole pH range and strong depression on galena in the pH range of 6−10. When DHDTP dosage is increased, the recovery of galena decreases rapidly, while that of the chalcopyrite decreases slightly. The satisfied separation results of artificially mixed samples are that the copper grade and recovery rates of concentrate are 24.08% and 81%, respectively, when the pH is 6 with 278 mg/L DHDTP. Zeta potential and adsorption measurements show that DHDTP has more strongly adsorption capacity to galena than chalcopyrite.

- by Siti Nur
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- Chinese Studies, Sinology, China, Flotation

Algae are traditionally classified according to biological descriptors which do not give information on surface characteristics that are important with respect to removal by water treatment processes. This review examines the character of freshwater algal populations from a water treatment perspective and evaluates the impact of their varying properties and the use of pre-oxidation on their removal by solid–liquid separation processes.. The characteristics shown to impact on treatment were morphology, motility, surface charge, cell density and the extracellular organic matter (EOM) composition and concentration. With the exception of density, these are not phyla specific. It was also shown that dissolved air flotation (DAF) was the most robust clarification method, where up to 99.8% removal was achieved compared to 94% for sedimentation when using metal coagulants. However, successful clarification relied heavily on the optimisation of preceding coagulation and flocculation and coagulant demand was important in this respect. Comparison of all available data reveals a relationship between cell surface area and coagulant demand. It is thus suggested that cell surface area would provide a basis for regrouping algae such that the classification is informative with respect to water treatment. However, the absolute coagulant demand is a result of both surface area and EOM influences. The latter are relatively poorly understood in comparison to natural organic matter (NOM) systems and this remains a limit in current knowledge.

- by Bruce Jefferson
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- Water Treatment, Filtration, Algae, Flotation

Na indústria cerâmica, o feldspato promove a formação de um vidro que mantém a forma do corpo cerâmico quando este passa pelo processo de queima. Para que o feldspato possa ser usado na fabricação de peças cerâmicas de elevada brancura o teor de Fe2O3 deve ser inferior a 1%. O objetivo deste trabalho foi concentrar feldspato reduzindo o conteúdo de Fe2O3 para um valor inferior a 1% por meio das técnicas de flotação e separação magnética. Utilizou-se o foiaíto proveniente do maciço alcalino de Poços de Caldas. A amostra foi inicialmente cominuída e caracterizada com relação à sua mineralogia e composição química. Em seguida, os experimentos de flotação e separação magnética foram realizados de forma isolada e em conjunto. Comparando-se as operações de flotação rougher e separação magnética isoladamente, a separação magnética foi mais eficiente na redução do conteúdo de Fe2O3. Além disso, observou-se que a etapa de separação magnética aplicada no produto da flotação é mais adequada para a redução do teor de Fe2O3. Por meio das operações de flotação seguida de separação magnética, o teor de Fe2O3 nos concentrados das flotações direta e reversa reduziram de 3,14% para 0,61% e 0

- by Mauricio Bergerman and +1
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- Mineral Processing, Flotation, Froth Flotation, Feldspar

Dodecylamine (DDA) is a commonly used collector in the froth flotation of quartz particles. The present work for the first time studies the effect of DDA nanobubbles (NBs) on the flotation of coarse particles (−425 + 300 μm, −300 + 212 μm and − 212 + 106 μm). For this purpose, 50 mg/l DDA was employed as a primary material for producing bulk NBs via hydrodynamic cavitation technique to be used in the flotation kinetics tests. For comparative purposes, pine oil (PO), Methyl Isobutyl Carbinol (MIBC) and polypropylene glycol (A65) with a concentration of 22.4 mg/l were utilized for generating NBs and also as a frother. According to the results, generated NBs categorized based on the stability and mean bubble size as DDA > PO > MIBC>A65. The flotation rate constants (k) and ultimate recoveries (R max) obtained in the presence of the DDA-NBs were substantially improved compared to the corresponding values given for the frother types NBs. That was mainly related to the chemical func-tionality of the agent together with its extended stability. The experimental results showed a R max of 97.5% using the DDA-NBs in the condition of without any frother; however, the highest recovery using common air bubbles (CBs) was obtained 90.8% by the PO. Additionally, the influential order of the three frothers and the DDA on flo-tation rate constant was shown as DDA > PO > MIBC>A65 for each fraction size. Finally, the results indicated that the k and R max of coarse particles were improved by 22% and 21% in the presence of the DDA-NBs.

- by Ahmad Hassanzadeh
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- Nanobiotechnology, Flotation, Surface Engineering, Micro and Nanobubbles