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The first of this two part series takes a look at some of the history and types of flotation as well as agents and mechanisms involved in it. Part two, next month, will examine flotation processes as applied to various sulfide and nonsulfide mineral ores. Flotation-"froth" flotation-is a physicochemical method of concentrating finely ground ores. The process involves chemical treatment of an ore pulp to create conditions favorable for the attachment of predetermined mineral particles to air bubbles. The air bubbles carry the selected minerals to the surface of the pulp, there forming a stabilized froth that is skimmed off and from which the predetermined mineral particles are recovered. Other minerals remain submerged in the pulp.

Jan 3, 1982

By James B. Duke, Ernest W. Greene

An idea of what is meant by "Ultrafine Minerals Or Slimes" as used in the title can be had by an examination of Fig. I. Particle size distributions are presented for a crude kaolin clay, a coarse fraction and a fine fraction. The crude kaolin as mined was blunged with water, degritted through a 325-mesh Tyler screen, and dispersed with sodium silicate. The dispersed crude was then centrifuged in the laboratory into the coarse and fine fractions shown in the figure. The distribution curves were obtained by the well known sedimentation technique of Casagrande' using a long arm centrifuge to obtain equivalent spherical diameters down to 0.2 microns on the finer fraction. Fig. 1 shows the coarse fraction kaolin to be 50% finer than 3 microns, while the crude kaolin is 50% finer than 1.4 microns, and the fine fraction 50% finer than 0.6 microns. For comparison 53 microns on the horizontal scale would represent Stokesian diameters which would just pass a 325- mesh Tyler screen, taking into consideration the Andreasen sieve correction factor of 1.22 X the screen opening.' Another helpful comparison is the surface areas, which in square meters per gram, are 0.044 for 53 micron particles, 0.77 for 3 microns, 1.65 for 1.4 microns, and 5.0 for 0.46 micron particles. Fig. 2 is an electron micrograph of a similar fine fraction kaolin showing the hexagonal plate- like particle shapes.

Jan 10, 1962

The SFR system utilizes a skimmer or extractor placed at or near the slurry-froth interface where there is a higher concentration of valuable mineral particles. With assistance of hydrocyclones, it is possible to classify the extracted particles into coarse and fine particle streams, that can be handled separately. It also allows the coarser solids to be separated from entrained low-value fines. The first test results with the SFR system significantly improved both coarse and fine particle recovery in a flotation cell. The SFR system was tested in the flotation circuit at a copper-moly concentrator, and the results show that the use of the skimmer has huge potential to increase the froth recovery (Rf) of both molybdenum and copper.

Jan 1, 2012

By C. Hansen, J. Killey

This paper discusses the replacement of AEROFLOAT ® 1 25 promoter by AERO ® 5688 promoter at Sonora Mining Corp.'s California Mother Lode concentrator. Flotation concentrate is trucked 120 miles to a leach plant in Nevada, so the reduced mass resulting from higher gold grades and reduced talceous gangue and barren pyrite resulting from this change in promoters has brought about a major decrease in shipping costs. Preliminary laboratory testing indicated that free milling gold and controlled amounts of pyrite could be floated using Aero 5688 promoter with reduced dosages of Aero 350 xanthate.2 Extensive plant trials confirmed that the new reagent suite could indeed maintain gold recoveries while reducing total mass. Improved froth characteristics also improved operating flexibility in treating various ore types, and overall reagent costs have been reduced.

Jan 1, 1991

By Carl Hansen

Sonora Mining Corporation (SMC) operates the 6,000 tonne per day Jamestown open pit gold mine in the Mother Lode district of California. The mine has been in operation since January, 1987, and has produced approximately 7,800 kilograms of gold since start-up. The property consists of five ore bodies lying along a five kilometer stretch of the famous Mother Lode vein system. At present, only the Harvard ore body is being mined. The Harvard pit is centered around a historic underground mine of the same name that was operated from 1896 to 1916. The present ore body averages 2.5 grams gold per tonne as free milling gold and auriferous pyrite. The project consists of the open pit mine and concentrator complex in Tuolumne County, California, and a carbon-in-pulp leach plant located near Yerington, Nevada.

Jan 1, 1990

By Bisshop J. P W

Maximum recovery of sulphide minerals by flotation is achieved over a limited size range. Valuable particles above and below this range have a smaller probability of being recovered. In the normal grinding-flotation operation, not all valuables are reduced to the optimum size range, and therefore sub- stantial losses occur. A significant improve- ment in the size distribution is not usually possible within the conventional circuit, and a more complex arrangement may be necessary to obtain optimum recovery of the valuable mineral. This problem is considered with refer- ence to the Mt. LyeZl concentrator. The performance of the existing circuit is dis- cussed, and it is shown that losses in recovery occur in both coarse and fine sizes. Laboratory tests indicate that regrinding the coarse particles results in an increase in recovery of up to 4%. Redistribution of plant grinding capacity to reduce initial grinding power by 6% and use this capacity to regrind coarse particles was considered. It is con- cluded that overall plant efficiency would be increased by 2% provided that overloading of the regrind mill could be avoided.

Jan 1, 1977

By J. G. Henning

Following completion of planned mining operations at the Goldcorp Dome Open Pit Mine, a high-grade Shaft Pillar located in the pit highwall was recovered. Mining of this Shaft pillar faced numerous rock engineering design and implementation challenges due to its remote position on the highwall and the presence of mine workings within the wall. The case example presented in this paper discusses the geotechnical investigation performed at the site, novel measures undertaken for installation of ground support required for rockmass reinforcement and for worker protection, as well as operational challenges to successful mining of the Shaft Pillar.

May 1, 2009

By Leahy G. J, Moxon N. T, Nicol S. K

Experimental work is described in which extremely dilute aurocyanide liquors are treated with novel surface-active complexing agents to produce a hydrophobic aurocyanide species. Subsequent aeration of these liquors causes accumulation of such species at the air-water interface and the aurocyanide complex is transferred to a froth concentrate. A detailed performance assessment of this process is made and this knowledge used in the design of a pilot plant facility. Early results indicate the feasibility of the selective recovery of aurocyanide ions from reclaimed residue dam water (approximately 0.2ppm Au) with upgrade ratios of the order 180:1. A further study was made applying ion flotation to the recovery of gold from a carbon-in-pulp (CIL) feed liquor (approximately 1.0ppm Au). The probable economics of this process compared to conventional CIL processing is also described. Successful development of countercurrent ion flotation for concentrating solids-free gold solutions may offer a lower cost alternative to existing gold ore processing technologies, or in more secondary applications such as concentrating dilute gold solutions or heap leach runoff. The technology may also have more generalised applications to other heavy metal process- Ing.

Jan 1, 1991

By Kai Kang, Jun Bao, Shouping Liu, Xiao Sun

Powder characteristics have a significant influence on selective laser melting (SLM) process. In this research, particle size, surface contour and the microstructure of IN718 powder used in SLM were tested, and the physical and chemical changes during heating process of the powder were investigated as well. The shape characteristic and fluid properties of IN718 powder were defined and measured. It is shows that most particles of IN718 powder exhibited nearly spherical shapes, and the particle size is about 22.95μm. On this basis, IN718 sample was fabricated by SLM process using the powder and the microstructure of the fabricated sample was investigated. The results indicated that the sample has a dense microstructure, no macro-defects but a few micropores and porosity. Compared with the powder, there was no new phase formed in the sample and melting point of the sample was little less than that of the powder.

Jan 1, 2015

By Yun-tao Xin, Yu Yi, Kang Yan, Gang Li, Xiao-dong Lv

This study investigated the selective removal of arsenic from high-arsenic dust in alkaline systems and the effects of different leaching conditions. The results indicated that the liquid–solid ratio, NaOH concentration, and sulfur dosage had a significant influence on the process. The leaching efficiency of arsenic reached 99.57%, while that of lead was as low as 0.03% under appropriate conditions. In particular, the addition of sulfur can effectively promote the leaching of arsenic and reduce the dissolution of lead in the solutions. An artificial neural network was used to model the leaching process. It consisted of a back-propagation artificial neural network model with a “6–10–2” structure that could effectively simulate and predict the value with more than 99% accuracy. Based on the difference in weights of the different parameters in the neural network model, the relative importance of the parameters related to arsenic and lead leaching efficiency was obtained, which followed the order of NaOH concentration, liquid–solid ratio, sulfur dosage, temperature, time, and stirring speed.

Jul 29, 2021

By P. L. Li, B. X. Song, C. H. Wang, T. Wang, Z. Hu

"The treatment of an oxidized copper-gold ore by stage cyanide addition was investigated. For cyanidation, free cyanide ion concentration can be an indicator of whether there is copper dissolved in cyanide solution, and maintaining the free cyanide ion concentration lower than 1.0 g/L could be an effective way to prevent copper dissolution and reduce cyanide consumption. For that purpose, stage cyanide addition was introduced to control free cyanide ion concentration within the range from 0.8 to 1.0 g/L. Cyanidation tests results indicate that gold extraction was still acceptable at reduced cyanide consumption with a lower copper extraction. Based on the experimental study, industry application works at Beiya concentrator of Yunnan province, China were successfully conducted. When the raw ore contains 2.95 ppm Au and 0.75% Cu, by stage cyanide addition method, the gold extraction was still 93% at reduced cyanide consumption of 2135 g/t, which was only half of one addition method, and the copper extraction dropped to only 5%, which indicated that dissolution was prevented for almost 75% of the malachites.INTRODUCTIONCyanide with its competency to form a strong complex with gold, is the most preferable lixiviant for gold leaching. However, cyanidation is not inherently a selective process since many other minerals present in the ore are also readily soluble, especially the copper minerals. Muir (2011) reported that every 1% reactive copper present in the ore consumes about 30 kg/t NaCN, which can have detrimental effects on the process efficiency and economics due to high cyanide consumption, reduced gold leach rates and poor gold recovery."

Jan 1, 2016

By Komosa T, Muir D. M

Mixtures of ammonia and cyanide at low concentrations leach gold selectively from copper-gold ores. The effects of various reagent compositions on three different ore types containing between 0.3 - 1.5 per cent Cu are reported. It is shown that the results and optimum compositions vary according to the ore, which is attributed in part to the mineralogy and adsorption of solution species on the mineral surfaces. The solution chemistry of the Cu-NH3-CN system indicates that Cu(CN)a - and Cu(CN)3 species are involved in the leaching mechanism. Rotating disc studies on pure gold and copper are reported which show that the Cu(CN)32- species leach gold at about half the rate of CN but leach copper at the same rate. The presence of ammonia retards the leaching rate further. Mixtures of Cu(CN)a3- and NH3 effectively leach gold from Telfer tailing without leaching copper. The role of ammonia appears to be to control the precipitation of copper rather than the kinetics of leaching.

Jan 1, 1991

By G. T. Lapidus, R. Zárate-Gutiérrez

Selective leaching of lead from a Pb-Ag-Zn concentrate with hydrogen peroxide in citrate solutions was studied at room temperature. Leaching tests were performed, varying the H2O2 concentration and the solid-liquid ratio, holding the solution pH constant at 7, and the citrate concentration at 1 M. Lead extractions of 100 % were achieved with 4 and 5 times the stoichiometric quantity needed to form elemental sulfur, with only a small amount of metal impurities dissolved (Ag, Zn and Fe). The lead solubility limit at those conditions was found to be ~21 g L-1. X-ray diffraction analyses of the leach residues were free of galena (PbS), while other metal sulfides, such as sphalerite (ZnS), chalcopyrite (CuFeS2) and pyrite (FeS2), were basically unaffected.

Jan 1, 2014

By Manlapig EV, Lawson F, Clarkson CJ

A low grade middling sample from Mount Isa, Australia, assaying 31.7 per cent zinc, 12.9 per cent lead and 14.5 per cent iron was leached under atmospheric pressure in sulphate and sulphate-chloride solutions with ferric ions as oxidants. About 96 per cent of the contained zinc was dissolved into a 0.5 M H2SO4 - 0.5 M Fe2(SO4)3 solution at 90¦C within three hours from a five per cent by weight slurry density mixture. The leaching process is very temperature-dependent, suggesting a surface chemical control. In the latter stage, the leaching rates levelled off and the leaching was most probably controlled by both surface chemical reaction and diffusion processes. The addition of chloride ions in the leach solution resulted in an increase in the leaching rate. About 95 per cent of the lead sulphide contained was converted to lead sulphate which precipitated and remained in the residue. Essentially no lead remained in solution and the low chloride concentration did not affect the precipitation of lead sulphate. Half of the iron orginally present remained in the residue as pyrite although essentially all the cadmium and 90 per cent of the copper initially present were dissolved. Some three per cent of sulphide sulphur was oxidised through to sulphate, about 67 per cent was converted to elemental sulphur which can be recovered by solvent extraction, the rest remained in the residue mainly as pyrite. Ferric sulphate and sulphate-chloride solutions can be used to effectively leach finely ground lead-zinc middlings and other bulk sulphide concentrates. A complete separation of zinc from lead and silver has been demonstrated.

Jan 1, 1993

By A. Wedepohl

Selective leaching of phases in charge chrome is used in a variety of industrial processes for the production of chromium chemicals. A mineralogical study was made of a range of local charge chrome samples, at various stages of leaching in sulphuric acid (20g/l at 90°C), using mainly a scanning electron microscope (SEM) together with an energy-dispersive spectroscopy analyzer (EDS), and X-ray diffraction techniques. It was found that the leaching behaviour of the different types of charge chrome depends largely on the nature of the secondary phases, which in turn depends upon whether the silicon content is above or below 4 per cent by mass. The leaching behaviour of high-chromium ferrite is anomalous, and it is postulated that the process is analogous to the corrosion of brass by dezincification. Keywords: charge chrome leaching, scanning electron microscope

Jan 1, 2000

By Kejun Liu

Platinum and palladium are usually dissolved together and followed by separation. In this study, the selective leaching of platinum and palladium from a secondary resource, such as dental waste, by using chloride solution (hypochlorite and chlorate) has been developed. Results indicate that about 100% of palladium could be initially extracted by the combination of 0.3 mol/L sodium hypochlorite (NaClO) and 0.068 mol/L sodium chloride (NaCl) at pH 1.2 and 298K in 1.5 hours, or the combination of 0.005 mol/L sodium chlorate (NaClO3) and 6 mol/L hydrochloric acid (HCl) at 298K in 0.5 hour. About 100% of platinum could be extracted from the residue by the combination of 0.47 mol/L sodium chlorate (NaClO3) and 12 mol/L hydrochloric acid (HCl) at 298K in 2 hours.

Jan 1, 2003

By Zainab Nasrullah, MontanaFrank Agyemang, Mehran Sadat, Richard LaDouceur

Rare earth elements (REEs) are valuable for various modern technological applications, including metallurgy, machine building, radio electronics, instrument engineering, nuclear engineering, and manufacturing. The extraction and separa-tion of rare earth elements (REEs) from their complex ores is challenging due to their distinct physical and chemical properties, contributing to their market scarcity. At present, REE recovery utilizes traditional pyro- or hydrometallurgi-cal processes. The overall process in the recovery and sepa-ration of individual elements from complex REE systems suffers from high energy demands and the use of many haz-ardous chemicals that negatively impact the environment. With the growing trend toward a circular economy aim-ing to balance sustainability, efficiency, and environmental impacts, this research is focused on using deep eutectic sol-vents (DESs): a combination of a quaternary salt: Choline Chloride and five organic acids: Oxalic Acid, Urea, and Ethylene Glycol, Lactic acid and Glycerol for the selective leaching of REEs from their complex ore which is proven to be green, selective, non-toxic, biodegradable, and cheap. The effects of different DESs and leaching time on the REE leaching efficiency were determined, and the optimum DES media were found to be Oxaline and Lactic Acid at which a leaching efficiency of 25% and 15% was achieved at 80°C respectively for cerium.

Feb 1, 2025

By A. D. Paul, Yoon R. H., C. I. Basilio

Considerable amounts of Fe3+ ions are released into solution when coal is exposed to 1-3 M acid solutions. These ions superficially oxidize the coal surface, and are reduced to Fe2+ ions. When provisions are made to generate the Fe3+ ions in solution, e.g., by inserting an anode whose potential is above the reversible potential for the Fe3+/Fe2+ couple, considerable amounts of mineral matter are liberated from the coal matrix. With many eastern U.S. bituminous coals, this mineral liberation is achieved selectively without significant breakage of the coal. It is believed that this process is induced by the osmotic pressure set-up in the crevices between the mineral matter and coal that are exposed to the solution. A theoretical model predicting the osmotic pressure is presented in this work, along with some results obtained with different coal samples.

Jan 1, 1992

By L. S. McNickle

[Commonly accepted maintenance methods are being outdated by the rapid acceptance and use of more complicated hydraulic circuitry on modern mining equipment. It is no longer adequate to use the maintenance program to merely repair or sustain equipment operation. Ever increasing operating costs place a huge premium on lost production time. It has, therefore, placed the maintenance programs in the position of being required to alleviate equipment malfunctions on production shifts and still attain the maximum unit life from each component part.]

Jan 1, 1961

By L. S. McNickle

Commonly accepted maintenance methods are being outdated by the rapid acceptance and use of more complicated hydraulic circuitry on modern mining equipment. It is no longer adequate to use the maintenance program to merely repair or sustain equipment operation. Ever increasing operating costs place a huge premium on lost production time. It has, therefore, placed the maintenance programs in the position of being required to alleviate equipment malfunctions on production shifts and still attain the maximum unit life from each component part. Ireland mine of Hanna Coal Co., which operates two production shifts and one maintenance shift per day, performs hydraulic maintenance with a plan that is geared to assure the bulk of work being handled on the midnight or maintenance shift. Production is thus allowed to continue without interruption from major hydraulic component malfunction. The plan is called selective maintenance because the specific part to be worked on and the time the work is to be accomplished are selected according to a definite plan.

Jan 10, 1961