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By Richard F. McFarlin

INTRODUCTION Phosphate, one of the three major elements essential for all living plants and animals, has been mined in Florida for over a hundred years. Comprising roughly 80% of the U.S. total and 25% of the world's supply, the bulk of the 35 to 40 million annual ton output is converted to chemical fertilizers. With the exception of one mine in north Florida near the Georgia state line, today's mining activities are centered in the middle of the peninsula just east/southeast of Tampa in Polk, Hillsborough and Hardee counties. These "bone valley" deposits extend into Manatee and DeSoto counties, but there is little active mining there as yet. Because strip mining is, perhaps, the ultimate environmental insult and because Florida has a proactive environmental community, it is not surprising that the mining of phosphate rock has become increasingly controversial. This paper describes how phosphate rock is currently mined, the environmental problems presented by mining and processing the rock, and some mitigating technologies being employed to answer such problems. THE PHOSPHATE DEPOSIT AND ITS EXTRACTION Florida's phosphate deposits containing the calcium phosphate mineral, carbonate-fluorapatite, are between ten and fifteen million years old. The typical "bone valley" matrix is 15 feet thick and lies under 20 to 30 feet of overburden.(Fig. 1) Both the sandy overburden and matrix are unconsolidated and can be removed with standard 45 to 65 cubic yard, walking electric draglines. After removing the overburden, which is windrowed nearby, the dragline operator casts the matrix into a "slurry" pit where it is broken up by high pressure water monitors. Pit pumps (with boosters where necessary) transport the matrix slurry through 16 to 20 inch pipelines to a washer where the three components of the matrix (sand, clay and apatite) are separated. The phosphates contained in central Florida matrix are approximately half pebble/half flotation feed, through the pebble ratio decreases as the industry mines southward. Again, the matrix is roughly equally divided among sand, clays and apatite. The phosphatic clays, 75% of which are less than one micron in size, leave the washer as a 3 to 5% colloidal suspension. The impoundment of these waste clays is one of the environmental challenges to be discussed later. The sand (silica) is separated from the similarly sized phosphate particles by a double float process (fatty acid followed by a reverse mine or cleaner float), and the sand tailings are then pumped to disposal or reclamation sites. The apatite flotation product is combined with the screened phosphate pebbles and stacked to dewater before shipping.

Jan 1, 1992

By G. R. Addie

While the cost of transporting raw phosphate matrix from a pit to a processing plant via slurry pipelines is more efficient than it could be by rail cars, conventional trucks or belt conveyors, it still amounts to many millions of dollars, and in many areas there still exists much room for improvement. By taking advantage of pipeline test data on different slurries, it is possible to reduce costs by optimizing pipeline diameters, operating velocities and slurry concentrations. Better wearing, more efficient pump designs are now available which, if applied correctly, can lead to significant savings. The authors discuss what benefits are possible in relation to the electrical operating and wear maintenance costs and go into some of the factors associated with taking advantage of these benefits, identifying what they see as being practically possible.

Jan 1, 1998

By John W. Sweeney

Florida is blessed with some of the worlds greatest phosphate rock deposits, and doubly blessed in that those deposits are uraniferous. Until recently, the uranium con¬tained in phosphate rock had been ignored, but spot mar¬ket prices in the $40-per-pound range have spurred actions which will soon transform the state into a major uranium supplier. In 1978, two plants in Florida and one in Louisiana went it on- stream to recover uranium oxide from phosphoric acid, and construction began on three other extraction facilities. Together, these six plants will be cap¬able of recovering 1940 t/y (2140 stpy) of yellow cake from Florida phosphate in the early 1980s, equivalent to 15% of the projected US requirement. By the year 2000, Florida phosphates will have produced a projected 49 000 tons (54,000 st) of uranium oxide to fuel the nation's nuclear reactors.

Jan 9, 1979

By John W. Sweeney

Florida is usually thought of as a vacation State, not a mining State, yet Florida has been the leading producer of phosphate rock in the United States for 85 consecutive years and in 1978 supplied over 80 percent of the national output and over 30 percent of the world's output. It is estimated that the Central and South Florida phosphates contain 412,800 short tons (374,000 metric tons) of U308, that 115,000 short tons (104,000 metric tons) of U308 will be contained in the wet-process phosphoric" acid procsssed in the United States through the year 2000, and that 54,000 short tons (49,000 metric tons) of U308 will be available from Florida. In 1978, two companies in Florida and one in Louisiana went on-stream recovering uranium oxide from wet-process phosphoric acid and three others started construction of U308 extraction facilities. These six companies will have the capacity to recover 2,137 short tons (1,900 metric tons) of U308 annually in 1980, which will account for about 15 percent of our domestic requirements.

Jan 1, 1979

By Weibai Hu

Four methods to assess the relative flotability of fine coal have been tested: flotation with frother only, flotation with frother and collector, salt flotation, and timed-release analysis. A practical and simple criterion which combines the separation efficiency (capacity factor and kinetic rate constant (intensity factor) has been suggested. Five coal samples are chosen and tested. Based on test results, it is concluded that the flotability test with collector and frother is closer to practice, and, according to the suggested flotability criterion, coal fines can be classified into four categories of relative flotability: very easy, easy, moderate, and difficult.

Jan 1, 1987

By Daniela Venter, Stephen Chryssoulis, Ken Stowe

"A sampling campaign was conducted at Kemess in order to identify and assess the chemical and physical factors, which control free gold flotation kinetics in the rougher and cleaner circuits. The rationale behind this approach was that accurate knowledge of the parameters affecting free gold flotation kinetics, can be used to determine how to accelerate free gold flotation. Collected samples were composites of 5-6 cuts over a four-hour period, at steady plant conditions.In the rougher circuit, coarser equidimensional gold particles floated ahead of the finer grained and the flaky gold. Sulphur followed by molybdenum and to a lesser extent silver enhanced gold flotation kinetics, while hydroxyl followed by carbonate ions induced depression."

Jan 1, 2003

By H. K. Lin

The effect of metallic iron fines on froth flotation of a sulfide ore was examined by comparing the flotation results with and without iron fines present in the flotation feed. Mild steel and ceramic laboratory ball mills were used to grind 600 g sulfide ore charges. The mild steel ball mill generated approximately 4.6 g of iron fines (0.8% of the ore charge mass) when grinding to a product size of 80% passing 200 mesh (75 mm). When a low dosage of a weak xanthate collector was used in flotation, the impact of the iron fines on sulfide flotation was marked. Higher dosages of stronger xanthate collectors rendered the impact of the iron fines much less significant. Consumption of the collectors by the powdery iron fines is believed to cause the differences observed in the flotation results. A galvanic effect on flotation was not evident in this study. The impact of the iron fines on silicates depression was also examined.

Jan 1, 2008

By Francisco Sotillo Zevallos

El presente trabajo describe la aplicación de la flotación como método simple de concentración en la recuperación de la plata a través de las cualidades físicas y físico-quimicos superficiales de argento-jarositas. La factiblidad de este método optimiza las técnicas de investigación y explica las dificultades y potencialidades de la recuperación por flotación de las argento-jarositas.

Aug 26, 1988

By J. Wasmund Concha

En los últimos años la innovación en la industria minera viene tomando cada vez mayor importancia puesto que será una necesidad para desarrollar proyectos económicamente atractivos. Dentro de ella un nuevo tipo de flotación viene ganando cada vez mayor importancia, nos referimos a la Flotación de Partículas Gruesas (FPG), es decir partículas mayores a 150µm y hasta 850µm. Se estima que para proyectos brownfield este tipo de flotación podría permitir ampliar la capacidad de planta hasta en un 25% solamente implementando el sistema de FPG, y sin la necesidad de instalar más molinos.

Sep 1, 2017

By Walter F. Morton

La mina y la planta concentradora de Chilete de la Northern Peru Mining & Smelting Co., están situadas en Cajamarca, norte del Perú, donde en 1948 se encontraron cubicadas cantidades de minerales de plomo- zinc, que fueron añadidas a las reservas de la mina. Posteriormente se construyó una planta de flotación que permitió mejorar la filtración de los concentrados y a su vez aprovechar al máximo los minerales de la mena como la ganga, así como su concentración de valores económicos en los mismos.

Jun 20, 1954

By Fernando Bermejo

El presente texto describe la implementación del método Flash - Flotation para el proceso de optimización de plantas concentradoras polimetálicas en la Compañía minera Raura donde se tienen diferentes gravedades especificas por cada especie mineralógica. Su aplicación comprende la fase de investigación (año 89), modificaciones (año 2002) durante la etapa de escalamiento industrial y la optimización (año 2004) de estos equipos en la empresa, los cuales no han requerido de una gran inversión. Asimismo, los beneficios de operar con la celda SK-80 y SK-240 directamente a la descarga de los molinos primarios, permite optimizar el control metalúrgico. En este sentido, la idea de separar el plomo tan pronto lo permita el sistema, es la forma correcta de optimizar la metalurgia de este en la Compañía minera Raura.

Sep 12, 2005

By Michael E. Kelahan, Glenn A. Gruber

A review of recent phosphate beneficiation developments shows that Flotaire cells, ranging from 0.20 m to 2.44 m in diameter, have been examined in pilot scale and commercial plants. Applications of the column cells have included sized feed fractions using anionic and cationic reagent systems. In plants where the Flotaire was installed as a test unit or as an optional circuit, its use has been largely discontinued. On the other hand, when management committed to installing the Flotaire as an integral part of the flowsheet, the performance expectations were met or exceeded.

Jan 1, 1988

By R. E. Zimmerman

ALTHOUGH flotation of coal is considered relatively new in the United States by coal-preparation engineers, actually it has been practiced to some extent for the past 30 years, It is practiced much more widely in Europe than in the United States. Commercial plants are operating in nearly all major coal-producing countries of the world. A froth flotation plant has been operating since 1930 at the Champion No, 1 preparation plant of the Pittsburgh Coal Co. Unfortunately the term flotation is widely used in the United States by coal-preparation engineers to designate dense medium processes of coal cleaning. As used here, flotation means those processes for cleaning fine sizes of coal in which the coal is collected in a froth or matte at or near the surface of a pulp. The refuse particles remain in the pulp. Two distinct types of flotation are practiced: froth flotation and agglomeration. FORMS OF FLOTATION The theory of the principles of flotation and of the physicochemical foundations surrounding this process has become a complex and scientific field and coal-preparation engineers contemplating use of flotation processes would do well to study the works of Gaudin, 2, 5 Taggart, 3 Zimmerman, 4 Wark, 6 Ralston, 7 Petersen. 8 Bulk Oil Flotation.-In this process the separation of mineral from gangue is accomplished by virtue of the fact that minerals of metallic lustre, as sulphides, or hydrocarbons, as coal and graphite, are wetted preferentially by oil in the presence of water and consequently pass into the interface between oil and water; while gangue or rock is wetted by water and remains in the medium. Beginning in 1860 with Haynes and later between 1897 and 1907, at least 25 patents were granted for bulk oil flotation. Large quantities of oil are required, generally 3 to 25 per cent by weight of feed, and recovery of such oil is a major problem. The Elmore process 3 (1901 and 1902) is an example of a bulk oil process, The Trent process (1902-25) has been used for the cleaning of coal on a commercial scale, According to E. W, Davidson 9 there were five such plants operating in the United States by 1925. They have since been abandoned.

Jan 1, 1950

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

By P. G. Claridge, G. P. Holmes, M. A. Redfearn

"IntroductionThe purpose of this chapter is to describe current practices in operation and maintenance of flotation circuits in Canadian mineral processing plants. The chapter consists of five sections covering description of equipment, typical flow diagrams, operating practice, instrumentation and maintenance. The approach to this subject matter is intended to be practical in nature, hence no deeply technical treatment of flotation theory will be included.Flotation is an extremely common method of beneficiation of ores. Reasons are the relatively low cost of flotation compared to many other processes, the wide range of minerals to which flotation may be applied and the high efficiency of separation which can usually be achieved. The flotation process as we know it today has been developed within this century and it has had a major impact on the mining industry. While flotation is commonly considered to be important because it provides a relatively simple method of separating minerals in complex ores, the availability of flotation has also made a multitude of mineral deposits in Canada into economically viable mining operations because it allowed production of a concentrate of valuable minerals from the ore. These concentrates could then be transported from geographically remote locations to centraHzed plants for further processing, although the existence of the remote and perhaps small ore body alone would not have justified installation of metallurgical processing plants on site and the grade of ore would not have justified direct shipment of ore.Some of the more common minerals concentrated by flotation are sulphides of copper, nickel, cobalt, iron, zinc, molybdenum, lead and arsenic, as well as non-sulphides such as sodium chloride, potassium chloride, phosphates, silicates, chromite, fluorite, limestone and coal. Precious metals are also recovered by flotation, generally in association with another sulphide mineral."

Jan 1, 1989

By W. D. Guo, Y. M. Zhu, B. B. Luo

The main chemical constituents of waste cooking oil are higher fatty acid glycerides, which can be used to produce anionic fatty acids for most non-sulfide flotation. However, using the mixed fatty acids (MFA) produced by waste cooking oil as collectors directly, the flotation effect is usually not satisfactory, especially at lower temperature or room temperature. There are very rare systematic studies about the reason for poor flotation performance of waste cooking oil. This study aims to investigate the flotation and adsorption characteristic of different types of fatty acids in waste cooking oil to find out what kind of fatty acids results in the poor flotation performance. This will provide technical supports and theoretical guidance for the waste cooking oil application in the field of mineral processing. In this study, MFA were produced from the waste cooking oil, and then separated into saturated fatty acids (SFA) as well as unsaturated fatty acids (UFA), which possessing different flotation properties. The properties of the MFA, SFA and UFA were analyzed by iodine value, melting point measurement, Fourier transform infrared (FT-IR) spectroscopy and quartz micro-flotation tests. The results showed that UFA was composed of fatty acids containing group—(CH=CH—CH2)n—, having an iodine value of up to 162.90, a melting point as low as -17.3 ? and stronger low-temperature floatability. In contrast, the SFA was made up with saturated fatty acids and a few oleic acids, with an iodine value of 48.97 and a melting point of 38.8 ?. SFA had shown poor collectability and required a flotation temperature higher than 35 ?. The results of zeta potential measurements, solution chemistry calculation and FT-IR spectra revealed that both UFA and SFA can be adsorbed on the quartz surface activated by CaCl2 via the chemical and hydrogen bonding. The reason MFA having a poor flotation performance is the SFA has an extremely high melting point which affecting the dissolution of the dispersion.

Jan 1, 2018

"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 D. Lascelles, J. A. Finch, E. El-Ammouri

Flotation separation is expected to be related to the degree of dispersion of the pulp. For instance, highly aggregated systems may show reduced selectivity, reduced entrainment and increased flotation rate. In an attempt to test the impact of aggregation on flotation, we have taken advantage of the effect of Mg ions. Using combinations of Mg2+ and pH gave a wide variation in aggregation of several Cu-Zn ores (measured by settling rate) and corresponding flotation response was determined by batch tests. The trials were conducted on-site at Louvicourt and Agnico-Eagle. In a majority of cases a similar trend in aggregation and flotation selectivity (grade at given recovery) was observed. At Louvicourt, improved selectivity with increasing aggregation at pH 10.5 was found. At Agnico-Eagle, an analogous association between aggregation and selectivity was observed at pH 11.5. It is suggested that aggregation influences particle entrainment, the increased effective particle size reducing gangue recovery and hence improving selectivity.

Jan 1, 2004

By E. W. J. Thornton

During the past six or seven years extensive research has been performed on ore samples procured at the Bruns1,vick Tin Mines which is located in the south-west corner of New Brunswi.ck. This property was originally staked by Mount Pleasant Mines and they did considerable metallurgical and geological work on a small copper, zinc and tin deposit. In 1969, the property was obtained by the Sullivan Mining Group and after much geological and diamond drilling work, an entirely separate ore body \Vas located two miles south of the previous workings. The major economic metals in this ore zone are tungsten, bismuth and molybdenite, but many other metals exist as well. As the ore contains a host of different mineral species, it can be seen that considerable time WRS required to develop a practical flow sheet.

Jan 1, 1977

By H. Saeedi Ali, A. J. Monhemius

"Anglo Asian Mining’s Gedabek mine is situated in the Lesser Caucasus mountains in Western Azerbaijan. The ore body is a complex copper-gold porphyry deposit, comprising intermixed oxidized, transition and sulphidic gold and copper-bearing ores. Gold in the sulphide ores is generally not refractory and is recoverable by cyanide leaching, but the secondary copper minerals, which are also cyanide soluble, lead to high cyanide consumptions. Ore processing at Gedabek is by agitation leaching for high grade ore (>1g Au/t) and heap leaching for lower grade ore. In order to cope with the high copper concentrations in the cyanide leach liquors, a unique combination of resin-in-pulp for selective gold extraction and SART processing for copper removal and cyanide recovery is used. In 2015, a flotation plant was added to treat the tailings from the agitation leach plant before the tails are sent to the tailings dam. This plant produces a copper sulphide flotation concentrate and also recovers some of the residual gold and silver in the tailings. Since February 2017, due to lower grades of gold and higher copper in the feed ore, the decision was taken to alter the flow sheet and to carry out flotation ahead of agitation leaching, to reduce the cyanide consumption during leaching by removing soluble copper minerals. The paper compares and contrasts the performance of the plant in the two configurations, namely, (i) leaching followed by flotation and (ii) flotation followed by leaching.INTRODUCTION In May 2009, Anglo Asian Mining started open pit mining for gold on its Gedabek property in the Lesser Caucasus Mountains in western Azerbaijan. Gedabek is situated on the highly mineralized Tethyan Belt that runs from the Himalayas to the Balkans. The ore body at Gedabek is a complex copper-gold porphyry deposit, comprising intermixed oxidized, transition and sulphidic gold-bearing ores. The sulphidic ores contain mainly pyrite and chalcopyrite, with some secondary copper sulphide minerals, such as bornite and chalcocite, and minor amounts of sphalerite, galena and tetrahedrite. Gold in the sulphide ores is generally not refractory and is recoverable by cyanide leaching, but the secondary copper minerals, which are also cyanide soluble, lead to high cyanide consumptions and passivation of free gold."

Jan 1, 2017