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INTRODUCTION From its beginnings in the first decade of this century, flotation has gradually moved to a predominant role in mineral separation. There are several reasons for this, the continuing trend toward treat¬ment of lower-grade and more finely disseminated ores being the major one. Not only has this been true for sulfide ores to which the process was first applied commercially, but also for most nonsulfide ores as well. A second factor has been the broad applicability of the process with respect to particle size; it is effective from 8 to 10 mesh to below 10m. Finally, more so than for any other separation process, flotation has almost no limitations in separating minerals. Gravity, magnetic, or electrostatic processes are either applicable to particular minerals, or to a restricted number of mineral combinations. Flotation, on the other hand, can utilize the wide range of surface chemical differences among minerals, and an equally wide range of reagents. The recent availability of selective flocculation capabilities on a commercial scale as an adjunct to flotation should remove one of the limitations to the process in the very fine particle range. History Although flotation was anticipated in a 19th century patent to Haynes, its first significant industrial uses were in the early 20th century in Australia. According to Hoover,' the Pottter-Del-prat pro¬cess had a "measure of success" at Broken Hill's Block 14 mine in 1905-1906, and was definitely successful at the BHP Mine, where it produced 80,000 tpy of zinc concentrates. Both the Mineral Separa¬tion and the Elmore processes had early trials in Australia also, with both successes and failures. The first application in the United States was in 1911, when the Hyde process was used by the Butte and Superior Copper Co. on a zinc ore in Montana. By 1916 Hoover could list 46 applications to copper, lead, and zinc ores, mainly in the United States. Ten years later Taggart2 listed almost a thousand patents covering processes and reagents which with few exceptions laid the foundations for modern practice. Included were: sulfidizing of oxides; leach-precip¬itation-flotation; cyanides, sulfites, sulfides, and oxidants for selective depression of sulfides; starch, tannin, and glue as depressants; and xanthates, dithiophosphates, and oleic acid as collectors. Within an¬other 20 years, all of these were in commercial use along with amines for floating silica from phosphates, and synthetic frothers were com¬peting with pine oil and cresylic acid. Flotation machine development followed a different course. Of the 170 patents listed by Taggart in 1927,1 those incorporating film and oil flotation-about a third of the total-were no longer then

Jan 1, 1985

"A cationic surfactant, tetradecyl tributyl phosphonium chloride (TTPC), was first used as a collector. Flotation characteristics of muscovite using TTPC have been investigated through flotation tests. And dodecyl trimethyl ammonium chloride (DTAC) was tested for comparison. Their adsorption mechanisms on muscovite surface were clarified using zeta potential measurement, DFT calculation and molecular dynamics (MD). The flotation results indicate that the recovery of muscovite decreases when the pH increases in the presence of surfactants. When a maximum of recovery was reached, the dosage of TTPC was 2×10-5mol/L which was half of that of DTAC. Zeta potential measurements confirm that the TTPC displays a stronger collecting power than DTAC and is a superior collector for the muscovite flotation. DFT calculation and MD simulations show that TTPC interacts with the muscovite mainly through electrostatic attraction and hydrogen-bonding. The conclusions drawn from purely theoretical computations matched remarkably well with the experimental results. Keywords: Quaternary phosphonium salts; Flotation collectors; Flotation INTRODUCTION Muscovite mica is widespread in igneous, sedimentary and metamorphic rocks. It has the general composition KAl2(AlSi3O10)(OH)2. Muscovite mica exhibits perfect cleavage along the (001) plane, which exposes interlayer potassium ions[1-3]. In aqueous suspensions, the potassium ions readily enter into solution, leading to the development of a net negative charge on the (001) plane[4-6]. The surface of the muscovite mica is negatively charged at all pH > 1[7]. Due to the negative charge surface over the whole pH range of 2–12, the muscovite mica would not be expected to respond to anionic collectors in the absence of an activator. Conversely, the mineral is readily recovered using cationic collectors. However, until now, various amines and their derivatives (with N atoms as the center) are still the only available cationic collectors which still had their shortcomings such as weak selectivity, low flotation speed. Since few types of cationic collectors could be used, in some sense, the limitations of collectors are increasing significantly and the cationic flotation is facing more and more challenges. Quaternary phosphonium salts, as novel cationic surfactants, are widely used in antimicrobial, catalysis and surface modification field due to their biological activities, hydrogen bonding capability, stability and superior group electrical property[8-10]. There are a number of processes where quaternary phosphonium salt surfactants have shown better properties than quaternary ammonium salts and amines. Although the adsorption of quaternary phosphonium salt surfactants at the bacterium–liquid interface has been studied thoroughly, the case of adsorption in mineral surface has not been investigated thus far."

Jan 1, 2016

By C. I. Basilio

The adsorption of O-isopropyl-N-ethylthionocarbamate (IPETC) and O-isobutyl-N-ethoxycarbonylthionocarbamate (IBECTC) on chalcocite, chalcopyrite and pyrite has been studied using UV and in-situ FTIR~ATR spectroscopy. Thionocarbamates were found -to adsorb strongly on chalcocite at pH 4-10, but consider-ably less on chalcopyrite and pyrite. The FTIR spectra show that the surface species of thiono-carbamates are bonded to metal atoms on the mineral surfaces. However, at high concentrations, IBECTC also forms physically-adsorbed species. Adsorption of these thionocarbamates cannot remove or prevent the formation of sulfoxy oxidation products on pyrite, unlike the case with the xanthate-pyrite system. This finding may account for the observed flotation selectivity of these reagents against pyrite. The spectroscopic information is compared with flotation test results.

Jan 1, 1988

By S. Chander

A series of nonionic and anionic surfactants were tested to enhance the flotation response of a low rank coal. An ethoxylated octyl phenol and several polypropylene polyethylene block copolymers were tested as nonionic surfactants. The anionic surfactant was a dioctyl sulfosuccinate. All the surfactants employed improved the yield significantly but the influence on grade was complex. Separate studies were conducted to determine the emulsification behavior of the surfactants. For the nonionic water soluble reagents tested, a correlation between emulsifying power of the surfactant and flotation was observed. An increase in the number of droplets produced in surfactant containing systems was considered to be the main reason for increase in the yield. Since it increased the number of collisions between dodecane droplets and coal particles. When a surfactant was introduced into the flotation pulp prior to addition of dodecane, it decreased the benefits of the surfactant significantly. The decrease was attributed to an increase in the wettability of coal and a decrease in the surfactant available for emulsification. When a suitable surfactant was added as a solution dissolved in the oily collector, a considerable increase in yield was observed.

Jan 1, 1993

By H. Polat, B. Mohal, S. Chander

Several nonionic surfactants and one anionic surfactant were tested to enhance the flotation response of a low-rank coal. The nonionic surfactants included an ethoxylated octylphenol and several polypropylene-polyethylene block copolymers, and the anionic surfactant was a dioctyl sulfosuccinate. All of the surfactants improved the yield significantly, but the influence on grade was complex. To elucidate the mechanisms involved, separate studies were conducted to determine the emulsification behavior of the surfactants. For the nonionic water soluble reagents, a correlation between the emulsifying power of the surfactant and the flotation response was observed. An increase in the number of droplets produced was considered to he the main reason for increases in the yield. However, a small amount of surfactant adsorption on coal is essential to promote adhesion of oil droplets. When the surfactant was introduced into the flotation pulp prior to addition of dodecane, the benefits of the surfactant decreased significantly. The decrease was attributed to both a decrease in hydrophobicity of coal through increased surfactant adsorption and a decrease in the surfactant available for emulsification. When a surfactant dispersed in oil was used, the transfer of surfactant to the aqueous phase was minimal, and a considerable increase in yield was observed.

Jan 1, 1995

By M. Li, J. D. Miller

Existing process technologies for the production of soda ash from trona involves dissolution in hot brine, sedimentation and filtration for the removal of impurities, and subsequent crystallization for the recovery of soda ash. In this regard, mining and operating costs, particularly energy costs, are higher than desired. A preferred processing strategy might be to remove gangue mineral contaminants from the plant feed prior to dissolution in hot brine. Such a preprocessing strategy at ambient temperature and pressure has been limited by the lack of satisfactory process technology. Now based on recent results from laboratory research at the University of Utah it seems that the run-of-mine trona ore can be treated at ambient temperature and pressure using a special flotation procedure to separate the gangue minerals and make a trona concentrate with a purity of almost 99% trona at a recovery of more than 97%. The concept of such a new processing strategy is discussed with respect to current plant practice.

Jan 1, 2002

By J. E. Gebhardt, D. W. Fuerstenau

The use of small quantities of polyacrylic acid (PAA) was found to significantly improve the flotation of fine-sized hematite particles at pH 4.1 and 0.001 M NaCl with sodium dodecykulfonate (SDS). Low polymer dosages before collector addition aid flotation by forming flocs of primary particles, but excess polymer results in low flotation yields due to surface saturation by the hydrophilic polymer. Contact angles, measured on a hematite disk, substantiate the hydrophilic nature of an adsorbed polymer film. Pre-adsorbed PAA reduces the amount of SDS adsorbed on the hematite particles, but the flotation of hematite flocs occurs, even at reduced amounts of adsorbed SDS, and is not depressed until PAA dosages in excess of the saturation value are used. Separation of a hematite-quartz mixture can be achieved by SDS flotation of PAA,-flocculated hematite. Maximum selectivity results with the addition of small quantities of PAA, while excess polymer is detrimental to the recovery of hematite. Consecutive flotation states on a single feed yield a higher grade hematite product at some expense to the overall recovery.

Jan 1, 1987

By M. C. Fuerstenau

Flotation data indicate that sulfonate and dodecylamine adsorb physically on Mn02 at ambient temperature. Oleate also adsorbs physically if the zero-point-of-charge of the Mn02 is sufficiently high. Chemisorption of oleate apparently occurs between pH 8 and 9, and this phenomenon is enhanced considerably at elevated temperature.

Jan 1, 1966

By S. G. Dixit

Alunite (KAl3(SO4)2(OH)6] is one of the important nonbauxitic resources for aluminum in U.S.A. The major gangue material associated with a unite ore body is quartz. Experimental results indicate that oleic acid flotation of alunite is quite effective in upgrading the ore. The flotation chemistry of the alunite/oleate system has been investigated using various techniques such as: hallimond tube flotation response, measurement of adsorption density using I4C labeled oleated, electrokinetic measurements, infrared spectral studies, contact angle measurements and thermochemical measurements using an isothermal microcalorimeter. Alunite has been found to float readily with oleate in the pH range 4-10.5 and its flotation response is enhanced at higher temperatures. The PZC of alunite has been determined to be at pH 7.2 ± 0.15 which agrees with what would be predicted from solution chemistry and from the flotation response with physically adsorbed collectors. Infrared spectra show a specific peak in the range 1585-1600 cm-1 which has been attributed to the formation of an aluminum oleate surface species. Both adsorption density measurements and infrared spectra indicate that during adsorption multilayers are formed. The heat of adsorption of oleate on alunite has been found to be endothermic and of the order of 4-6 KJ/ mole.

Jan 1, 1980

By M. S. Celik, H. Du, J. D. Miller, F. Cheng, O. Ozdemir

"In this paper, recent progress with respect to the flotation chemistry of soluble salt minerals is reviewed, and some of the more relevant issues including the hydration states of ions, the interfacial phenomena of salt surfaces and the flotation behavior of selected soluble salts are discussed. Due to the high solubility, the flotation of most soluble salts has to be carried out in their saturated brines. Anecdotal evidence has suggested that the hydration states of the ions have significant influence on the physicochemical properties of the solutions, the surface charge and wetting characteristics of the minerals, the collector adsorption states and, further, the flotation behavior of the soluble salts. In this regard, reviewing past research findings, efforts are made to establish a correlation between the ion hydration states with the flotation behavior of the soluble salts. Further, advances in understanding the significance of colloid adsorption involved in the soluble salt flotation process are addressed, and future research efforts to understand the soluble salt flotation chemistry are suggested.IntroductionSoluble salt minerals are essential raw materials for the production of a variety of commodities, fertilizers, potassium hydroxide, soda ash, magnesium compounds and other chemicals. These soluble mineral resources can be processed using flotation technology and, currently, more than 80% percent of the world’s potash is produced by the selective flotation of KCl crystals (sylvite) from other salt crystals, predominately NaCl (halite) and other more complex salts (Searls, 1990). Despite the successful application of flotation technology in the potash industry, the mechanisms for collector adsorption on soluble salts have not yet been fully understood and, therefore, have been of considerable interest to flotation researchers for many decades."

Jan 1, 2015

By J de Cuyper, N. R. Tipman, G. E. Agar, L. Laré, W. Freyberger

The flotation chemistry of the commercial INCO matte separation process was investigated. The slow cooling of Bessemer converter matte forms discrete phases of Cu2S and Ni3S2 and a Cu-Ni alloy. After magnetically removing the alloy, the Cu2S and Ni3S2 are separated by flotation at pH 12.4 (saturated lime) using diphenyl guanidine (DPG) as both collector and frother. DPG has been used exclusively in this flotation process because of its unusual selectivity for copper minerals. The surface product resulting from chemisorption of DPG onto the Cu2S was identified as the double salt Cu(DPG)2SO4,.CU(DPG)2(OH)2. The adsorption followed Langmuir behaviour up to a monolayer coverage. In the absence of DPG, the rapid adsorption of oxygen by Cu2S in flotation pulps was observed. The surface product was identified as the insoluble basic copper sulfate CuSO4.3Cu(OH)2 with the production of sulfate ion. In the presence of DPG, the oxidation reaction appears to be suppressed. The frothing properties of DPG and commercial frothers were compared. DPG is not a powerful frother. Batch flotation tests confirmed that DPG is a highly selective collector when compared to most sulfhydryl collectors.

Jan 1, 1976

By Wang Dianzuo, Luo Lin, Hu Yuehua, Qiu Guanzhou

This paper introduces a novel classification approach named the flotation classification approach which works by controlling interactions between particles. It differs considerably from the conventional classification processes operating on mechanical forces. In the present test, the micro-bubble flotation technology is grafted onto hydro-classification. Selective aggregation and dispersion of ultrafine particles are achieved through governing the interactions in the classification process. A series of laboratory classification tests for -44 pm kaolin have been conducted on a classification column. As a result, about 92 percent recovery for minus 2 pm size fraction Kaolin in the final product is obtained. In addition, two criteria for the classification are set up. Finally, a principle of classifying and controlling the interactions between particles is discussed in terms of surface thermodynamics and hydrodynamics.

Jan 1, 1995

By S. R. S. Sastri, K. K. Bhattacharya, K. S. Narasimhan

Experimental results obtained on the recovery of below 0.5 x 10-3m coal fines by flotation employing geometrically similar columns of 0.056m, 0.080m, 0.100m and 0.220m diameter have been presented. The hydrodynamics of such a unit as well as its performance have been related to operating parameters to establish optimum conditions. The results have further been analysed critically in the light of the known relationship on the behaviour of similar systems to assign reasons for the critical factors established in a bid to reduce the empiricism required to be followed in the scale up of such a unit.

Jan 1, 1988

By Joachim H. Schubert, David G. Hulbert, Ian K. Craig, Roger G. D. Henning

This paper presents a stabilizing controller for flotation plants which uses a quasi-multivariable technique. The controller monitors all the levels in the plant, and by anticipating interactions between various parts of the plant, is able to stabilize the plant far more successfully than the normal plant control. Once stabilizing control has been achieved, optimization of the process becomes easier and more sustainable. An estimate of the improvement in metallurgical performance is made and a singular value analysis was conducted to verify that the multivariable algorithm will theoretically control better than a collection of individual PID loops. Metallurgical results are presented to show that the improvements are attainable in practice. Control by the Mintek algorithm was alternated with normal plant control, to show that the improvements are statistically significant.

Jan 1, 1995

By Wen Tao Liu, Tong Tian, Fu Sheng Niu, Xiu Man Liang

The level of automation employed in flotation production is relatively low. In an actual concentrator, operators use their judgment to adjust the production state based on the visual characteristics of the flotation froth surface. There are shortcomings, such as strong subjectivity and lagging process operation, that easily cause the waste of manpower and material resources. Machine vision technology is introduced to replace human visualization, achieving a quantitative description of the visual characteristics of the froth surface. The state variable parameters are provided for the identification of the flotation conditions.

By Wen Tao Liu, Tong Tian, Fu Sheng Niu, Xiu Man Liang

In order to address the difficulty of accurate segmentation of froth images of different sizes, a method of froth image segmentation based on highlight correction and parameter adaptation is proposed. First, a machine vision system on a single-cell flotation machine is built to collect froth images. Homomorphic filtering is used to improve the uneven brightness and shadow of the images. Fuzzy c-means (FCM) clustering is then utilized to classify similar highlights that belong to the same froth. After Otsu threshold segmentation, a parameter-adaptive morphological operation is used to extract the marker points and edge bands and correct the froth edges in the original image. Finally, the modified image is filtered by morphological reconstruction, and the highlight mark is used as the local minimum point for watershed segmentation. Three sizes of froth images are segmented in comparative experiments. The results show that the proposed method is suitable for the segmentation of froth images of different sizes. The position of the extracted segmentation line is close to reality, with average over-segmentation and under-segmentation rates for froth images of 2.6% and 6.8%, respectively. The froth image segmentation performance is stronger than that of the other methods examined.

By Wen Tao Liu, Tong Tian, Fu Sheng Niu, Xiu Man Liang

In order to address the difficulty of accurate segmentation of froth images of different sizes, a method of froth image segmentation based on highlight correction and parameter adaptation is proposed. First, a machine vision system on a single-cell flotation machine is built to collect froth images. Homomorphic filtering is used to improve the uneven brightness and shadow of the images. Fuzzy c-means (FCM) clustering is then utilized to classify similar highlights that belong to the same froth. After Otsu threshold segmentation, a parameter-adaptive morphological operation is used to extract the marker points and edge bands and correct the froth edges in the original image. Finally, the modified image is filtered by morphological reconstruction, and the highlight mark is used as the local minimum point for watershed segmentation. Three sizes of froth images are segmented in comparative experiments. The results show that the proposed method is suitable for the segmentation of froth images of different sizes. The position of the extracted segmentation line is close to reality, with average over-segmentation and under-segmentation rates for froth images of 2.6% and 6.8%, respectively. The froth image segmentation performance is stronger than that of the other methods examined.

By J. P. Morgan

The Vesta Preparation Plant of the Jones & Laughlin Steel Corporation is located on the Monongahela River, eight miles south of Brownsville, Pennsylvania. This plant is capable of cleaning 2400 NT/hr of a mixture of Pittsburgh seam high volatile coals from the Vesta and Shannopin mines to produce a metallurgical coal of 6.75% ash and a steam coal containing 14% ash. Heavy media vessels are utilized to upgrade the coarse coal while launders and tables. handle the -1/4" fraction of the raw coal feed. Cleaned -coal goes to boot classifiers where the +48 mesh material settles and is removed by bucket elevators. This 1/4 x 48 mesh material is then sent to centrifugal driers for dewatering. As designed, the minus 48 mesh fraction overflows the boot as a 7 to 8% solids slurry and is recovered by cyclones and a thickener and dewatered by filtration. The-products of the heavy media circuit, the launder-table-boot-drier circuit and the cyclone-thickener-filter circuit are combined to constitute the shipped metallurgical coal. This Vesta-Shannopin mix is combined at J&L's Pittsburgh and Aliquippa Works with purchased low and medium volatile coals for the production of metallurgical coke.

Jan 1, 1962

By S. V. Tracy

The Outokumpu Skim-Air Flash Flotation machine was developed to separate valuable mineral from gangue as early as practical by floating it with specially designed flotation equipment installed in the grinding circuit. Machines already in service have shown the ability to produce final grade concentrate with an increase in overall recovery and flotation rate while decreasing filter cake moisture and reducing fluctuating feed grades to conventional flotation circuits. The first US production test was carried out in a southwestern copper concentrator with successful results. This report describes the results of the test along with an explanation of the process and the benefits obtainable.

Jan 1, 1986

By L. Gutierrez, J. S. Castro S. Laskowski

Water is a medium in which flotation takes place, and flotation efficiency is highly dependent on water quality. Of the total water resources on Earth, less than 2.5 percent is fresh water. This water is used in agriculture, by households and by industry. Among the industrial users of fresh water, the mining industry occupies an important position. Furthermore, mining operations are often located in arid areas with very limited access to fresh water. The demand for and shortage of water in these parts of the world, such as the Atacama Desert in Chile, makes the use of seawater by the mining industry the only sustainable solution.