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By L. Heber Cole

The search for potash in western Canada during the years of the great war led to the staking of claims on many of the "alkali lakes" and sloughs which occur in numerous localities in the morainic areas of the prairies, as well as in British Columbia, in the hope that potash salts would be found in commercial quantities. While the search for potash, up to the present time, has been disappointing, the prospecting of these areas has demonstrated that Canada possesses large reserves of sodium and magnesium compounds, principally in the form of sulphates, carbonates and chlorides. he writer first became interested in these deposits in 1911 while investigating the sodium chloride springs of northern Manitoba. In the fall of that year a number of the sulphate ? deposits in Saskatchewan and Alberta were visited, but owing to the excessive rains at that period, all the deposits were under water and only a few brine samples were obtained. Owing to pressure of other work investigations of the alkali deposits in western Canada, by the Mines Branch of the Department of Mines, could not be undertaken until the field season of 1921, but since that time the work has been continuous. During the summer of 1918 a reported discovery of a large deposit of potash bearing salts was featured in western papers and in a short time practically all the lakes and sloughs of the prairie provinces, which showed the least indication of being saline, were staked for potash. This reported discovery was not substantiated on investigation and many of those who had staked claims allowed them t~ lapse without the slightest effort to determine the character of the material in the deposits which they? had leased.

Jan 1, 1924

By S. H. Ash

NO MORE important question has come before the coal-mining industry in many places, especially in the anthracite region of Pennsylvania, than prevention of stream pollution by mine drainage. Available information on acid mine drainage in the anthracite region of Pennsylvania indicates that a pollution problem must be solved in any program of anthracite mine drainage. The major problem concerns satisfactory disposal of the daily average mine-water discharge of 327,000 gallons per minute (g. p. m.), or 472 million gallons per day (g. p. d.), containing a free-acid load of 431 tons or a total acid load of 934 tons a clay as H2S04. This report indicates the scope of the problem and gives some suggestions concerning its solution.

Jan 1, 1951

By Santosh Kumar Ray, DEBASHISH MISHRA, Niroj Kumar Mohalik, SOMU MANDAL, Jai Krishna Pandey, Asfar Mobin Khan

Coal is a low-cost and high-calorific-value fuel. The coal mining industry worldwide has been suffering from severe accidents due to coal dust explosion hazards since its inception. Statistically, it was observed that 12,489 fatalities had occurred in 104 reported mining accidents from coal dust explosions during 1900–2020. There are numerous methods for detection, prevention, and control of coal dust explosions in mines. The underground mining environment is unpredictable and has an array of variables. These undulating factors make it difficult to prevent or control the coal dust explosion hazard. However, coal mining is done aggressively throughout the world, especially in developing countries as coal is a major source of thermal energy used in power plants contributing to about 38% (IEA, (2019), World Energy Outlook, IEA, Paris https:// www. iea. org/ repor ts/ world- energy- outlo ok- 2019.) of world electricity. Worldwide, coal dust explosibility studies are carried out in experimental mines, laboratories, and simulations. The complexity, lack of proper infrastructure, and unavailability of laboratory equipment sometimes make it difficult to study coal dust explosibility. The authors have discussed in detail and proposed that the CFD modelling can be a viable option for studying and evaluating coal dust explosibility.

Jun 29, 2022

By Alan Alves Vieira

Uma das maneiras mais eficientes de aumentar a campanha dos refratários de conversores é o uso de técnicas de slag splashing e slag coating. Nestes processos, antes de sua execução, a escória de fim de sopro é modificada pela adição de materiais contendo, principalmente, MgO. Escórias de conversor contendo alto teor de FeO tem, como fase de equilíbrio mais provável a magnesiowustita (MW). Este estudo visa determinar se, nos curtos tempos de processo em conversor, e sempre a temperaturas bastante inferiores ao ponto de fusão do MgO, ocorre a dissolução do MgO e a saturação da escória em MW ou se a escória se mantém fora de equilíbrio. Os resultados indicam que a MW é formada e, em muitos casos, sua composição pode ser prevista com razoável precisão através de cálculos de equilíbrio por termodinâmica computacional.

Oct 30, 2017

By M. B. Dusseault, A. Pirayehgar

"There is concern that hydraulic fracturing (HF) near an existing critically stressed fault could trigger slip and generate a seismic event of significance. To this end, a mathematical discontinuum model representing a naturally fractured rock (NFR) mass containing a fault is created, and fault slip response to fluid injection is studied. UDECTM is used as a Discrete Element Method (DEM) approach to define the seismic moment, and also to assess the influence of injection and slip on further shear slip propagation. In most of the simulations, slip and dilation take place along a number of oriented fracture surfaces, so it is reasonable to assume that in a real case, microseimic emissions would accompany each slip “event”. The moment magnitude scale (Mw) is used to measure the size of the microseismic event in terms of the energy released. Seismic moment is a measure of the total energy (work) released during a seismic event and is used to measure its size. From another aspect, the injection energy is calculated as the total energy required for achieving the hydraulic fracturing; this is viewed as energy to open fractures against the ambient stress field and much of it is potential stored energy that can be released and create discontinuities (work of fracture), deformations (W=F·d), heat and radiated seismic energy. A small amount of the total released energy is transformed to radiated seismic energy and another small amount results in tensile fractures. Fracture energy is used to calculate the work required to create fracture surfaces. Comparing the energy release by fracturing or seismic events indicates their contribution to the total amount of released energy or total work. The amount of energy associated with the stick-slip event is small compared with the overall work done to generate the distortions (i.e. increases in aperture by forcing them open) in the rock mass, and much of the energy in slip is lost as heat from the plastic deformation, rather than as radiated seismic energy.Microseismic monitoring shows the spatial distribution and magnitude of seismicity associated with slip of bedding planes and natural and incipient fractures. Work calculations have been undertaken to look at the various sources of energy storage (elastic strain energy) or dissipation (slip), and likely the energy losses from viscous dissipation could be addressed as well, helping to clarify HF processes in NFRs."

Jan 1, 2015

By Paul M. Tyler

Calcium chloride is a conspicuous example of a former waste product that has found a place for itself in the onward march of civilization. Formerly considered a troublesome constituent of the effluent sewage of many chemical manufacturing plants and salt works, it has now become a commercial product of substantial importance, with sales aggregating almost six million dollars in 1929. The point has not yet been reached where it would seem profitable to undertake large-scale production of calcium chloride as a main product, but as a byproduct it has become an item that warrants serious consideration by all who are in a position to recover it at sufficiently low cost. The largely increased demand for bromine and for certain magnesium salts, which are likewise potential byproducts associated with calcium chloride in most salt-works bitterns (and brines generally), adds further impetus to commercial research directed toward the fuller utilization of the natural saline resources of the United States.

Jan 1, 1934

By J. B. Yianatos

This paper addresses the impact on performance of column height (H), and column height to diameter (H/D) ratio by modelling the effect of HID on mixing and consequently on recovery and grade. Mineral recovery increases with increasing H/D ratio for a constant column volume and feed flowrate, while the concentrate grade decreases to a minor extent. Columns 10-15m in height with H/D-10 are well suited for feed rates 150-600 L/min. Maximum H/D is determined by the gas carrying capacity, an important consideration for pilot units where H/D?200.

Jan 1, 1987

By Çisem Tuba, Ismail Girgin

"Comparative atmospheric H2SO4 and H2SO4 + H2O2 leaching experiments were performed using a Turkish lateritic nickel ore containing 1.52% Ni. In the leaching tests; acid concentration, temperature and leaching time were considered as main variables and the dissolution behaviour of the ore were studied by Ni, Fe, Co and Mg analyses. The dissolution values in the H2SO4 leaching experiments were observed to increase up to 60% (w/w) acid concentration and a temperature of 95°C. Increase of H2SO4 concentration above 60% at 95°C caused decreases in all the dissolution values and this was attributed to the formation of Fe2(SO4)3 and Fe2(SO4)3•HSO4•H2O type compounds. At the considered optimum H2SO4 leaching conditions ([H2SO4]= 45%, T=95°C, t=45 min); dissolution values reached for Mg, Ni, Fe and Co were determined as 99.12%, 95.58%, 92.63% and 78.37%, respectively. An activation energy of 30.57 kJ/mole was determined for nickel dissolution from the evaluation of the kinetic data obtained for H2SO4 leaching showing that the dissolution was controlled by external diffusion and chemical reactions. Caro’s acid solutions were prepared at H2SO4/H2O2 mole ratio of 3 for varying initial H2SO4 concentrations and leaching tests were performed at 25°C. Co behaved very differently and a dissolution value of 83.94% was obtained even at 5% acid concentration in 60 minutes reaction time. Complete dissolution of Co was obtained after 30 minutes of reaction time at 60% initial H2SO4 concentration and the corresponding dissolution values for Mg, Ni, and Fe were reached to 96.16%, 94.27% and 89.46%, respectively. Although the H2SO4 + H2O2 leaching experiments were conducted at 25°C, it was realized that the temperature of the leaching medium was increased to 122°C after four minutes of reaction time due to probable exothermic reaction(s) at 60% initial acid concentration."

Jan 1, 2014

By A. D. Kalogeropoulos, T. N. Michalakopoulos

This paper deals with the numerical simulation of rock cutting laboratory tests using the discrete element method. The main objective is to provide a method for calibrating numerical DEM models of rock cutting in a systematic way so that realistic results are yielded. The numerical models are developed with the discrete element code Yade, which models rocks as a collection of bonded spheres. The models are calibrated in a four-step process based on the design of experiments method and optimization. The calibrated models are evaluated both quantitatively and qualitatively against actual laboratory cutting tests, in terms of the ratio of the simulated mean cutting force to the actual one and the cutting force time series, respectively. The fully calibrated models showed that the simulated cutting process matched qualitatively the actual cutting force recordings and underestimated the mean cutting force by approximately 3%. It is concluded that well-calibrated numerical simulations of the rock cutting process can provide not only a better understanding of the process itself but also quantitative data regarding the cutting force and energy requirements.

Dec 28, 2022

By L. A. Delano

DURING 1916, the St. Joseph Lead Co. milled 2,505,670 tons of ore. This is a daily operating average of 7855 tons. The economic concentration of such a large tonnage necessarily requires a plant equipped with modern machinery and operated efficiently. The milling process used in producing this output has been a gradual development through the long period of years that the company has been in existence. HISTORICAL SUMMARY OF MILLING PRACTICE Ore was first mined at Bonne Terre, Mo., in 1864. The early milling practice was crude. It consisted of breaking the ore into small pieces by hand, pulverizing in a Blake crusher and a pair of Cornish rolls to approximately minus 6 mm., and jigging in the old-fashioned hand jigs. Only the coarse heavy galena was saved, the gangue being shoveled off and discarded. The output for the first year under this method was only 240 tons of pig lead. The first mill of the company was a combination of extensions and additions built from time to time as the mines developed. It was a museum of early mulling machinery, such as jigs, percussion tables, huddles, dolly tubs, log washers, etc., following no definite flow sheet. The chats, or tailings, were hauled to waste dumps by mule and ox teams, as much as 500 tons per day being moved in this manner, until a railroad was built in 1880. This mill was burned in 1883, at which time the annual output had reached approximately 7300 tons of pig lead. A new mill of 500 tons capacity was designed and built by C. B. Parsons. This mill has been admirably described by H. S. Monroe.1 The ore was crushed in Blake crushers, Cornish rolls, through 6-mm. screens, and treated by jigs of the Parsons type, percussion tables and log washers, or trunking machines, for cleaning the galena. The middlings were recrushed in rolls and treated on Harz jigs. The mill was operated without change, except later installing Gates crushers and en-

Jan 9, 1917

By L. A. Delano

During 1916, the St. Joseph Lead Co. milled 2,505,670 tons of ore. This is a daily operating average of 7855 tons. The economic concentration of such a large tonnage necessarily requires a plant equipped with modern machinery and operated efficiently. The milling process used in producing this output has been a gradual development through the long period of years that the company has been in existence. HISTORICAL SUMMARY OF MILLING PRACTICE Ore was first mined at Bonne Terre, Mo., in 1864. The early milling practice was crude. It consisted of breaking the ore into small pieces by hand, pulverizing in a Blake crusher and a pair of Cornish rolls to approximately minus 6 mm., and jigging in the old-fashioned hand jigs. Only the coarse heavy galena was saved, the gangue being shoveled off and discarded. The output for the first year under this method was only 240 tons of pig lead. The first mill of the company was a combination of extensions and additions built from time to time as the mines developed. It was a museum of early milling machinery, such as jigs, percussion tables, buddies, dolly tubs, log washers, etc., following no definite flow sheet. The chats, or tailings, were hauled to waste dumps by mule and ox teams, as much as 500 tons per day being moved in this manner, until a railroad was built in 1880. This mill was burned in 1883, at which time the annual output had reached approximately 7300 tons of pig lead. A new mill of 500 tons capacity was designed and built by C. B. Parsons. This mill has been admirably described by H. S. Munroe.' The ore was crushed in Blake crushers, Cornish rolls, through 6-mm. screens, and treated by jigs of the Parsons type, percussion tables and log washers, or trunking machines, for cleaning the galena. The middlings were recrushed in rolls and treated on Harz jigs. The mill was operated without change, except later installing Gates crushers and en-

Jan 1, 1918

By Seth C. Schaefer

[As part of the Bureau of Mines effort to provide thermodynamic data for advancement of mineral resources technology, the standard Gibbs energies of formation (?G°f) of MnS (manganese sulfide) and Fe0.9 S (pyrrhotite) were investigated with a high-temperature galvanic cell employing stabilized Zr02 (zirconia) as the electrolyte. Potential measurements were obtained for the cell Pt, MnS, MnO, S02 (g, 1 atm)//Zr02//02(g, 0.0114 atm), Pt with the overall cell reaction MnS (s) + 1.5 02 (g, 0.0114 atm) = MnO (s) + S02 (g) . (1) These results give the standard Gibbs energy of formation of MnS for the reaction Mn (s) + 0.552 (g) = MnS (s) (2) ?G°f = -66.487 + 15.19 x 10-3T±0.207 kcal/mole (896.4 - 1,208.1 K) (3) where temperature (T) is expressed in kelvins. Similar measurements were obtained for the cell Pt, FeO .9S, Fe304 , S02 (g, 1 atm) //Zr02//02 (g, 0.0114 atm) , Pt with the overall cell reaction 10/3 FeO .9 S (s) + 16/3 02 (g, 0.0114 atm) = Fe.,04 (s) +10/3 S02 (g). (4) These results yield the standard Gibbs energy of formation for the reaction 0.9 Fe (s) + 0.5 S2 (g) = Fe0.9 S (s) (5) ?G°f = -35.229 + 12.67 x 1073T+-0.104 kcal/mole (839.5 - 1,086.6 K). (6) A third-law analysis of MnS data yields a standard enthalpy of formation (AH°f) for the reaction Mn (s) + S (rh) = MnS (s) (7) ?H°f298 = -51.16±0.21 kcal/mole (8) A similar third-law analysis for Fe0.9S data yields a ?29°f298 for the reaction 0.9 Fe(s) + S(rh) = FeO .9S(s) (9) ?HO\°f298 = -24.01±_0.15 kcal/mole. (10) ]

Jan 1, 1980

By Milton Camino

El presente texto describe los antecedentes geológicos del yacimiento orogénico El Gigante, el cual presenta una mineralización filoneana del tipo relleno de fracturas asociada a estructuras de un lineamiento principal NW-SE. posicionándose como una de las franjas metalogenéticas de oro más importantes de la región y del mundo. De forma que se busca difundir los últimos resultados de la exploración a través de los nuevos descubrimientos en profundidad y los nuevos sistemas de vetas al borde Este del Batolito De Pataz. Así como formular un modelo que integre geología, mineralogía, cronología y geoquímica del yacimiento El Gigante, que permita mejorar el entendimiento de los procesos de formación de los yacimientos orogénicos de la franja metalogenética de Pataz y oriente al descubrimiento de nuevos recursos minerales.

Oct 21, 2015

By S. M. Runke

An earlier Bureau of Mines report4/ reviewed and summarized all reports of investigations dealing with the coarse grained pegmatites of the Black Hills of South Dakota to dune 1951. It was proposed, and the hope was expressed in this report, that future progress in the development of the technology of the mining and beneficiation of the pegmatite deposits would be rapid enough to make it possible to issue annual progress reports. Although notable progress has been made in the treatment of pegmatite material, it has not been rapid enough to justify annual reports

Jan 1, 1954

By George A. Guess

THE increasing demand for greater speed and more accuracy, in making daily assays of ores and products from mills treating material containing but very small quantities of lead and copper, has caused the older analytical methods to be supplanted by new ones devised to meet the needs of modern work. For " control " work in copper analyses, I had, previous to the present equipment, introduced in my laboratory the ordinary electrolytic method, using hollow cylindrical electrodes, and with these I began a series of experiments in determining the lead-content of daily mill-samples and controls. The results, proving accurate and satisfactory, I then devised, with Mr. H. E. T. Haultain, a cheaper electrode than the ordinary jacket electrode, which costs from $15 to $20,-the expense of the older form making the installation of many units very costly. The form of cathode finally adopted as the most satisfactory, shown in Fig. 1, is cut from 0.001-in. platinum foil. It is 12.5 cm. long, and is divided into a blade 4 cm. wide and 6.25 cm. long, and a tongue 0.7 cm. wide and 6.25 long, the immersion area being 50 sq. cm. and weight 1.5 grams. The blade is first sand-blasted and then corrugated lengthwise, in order to impart the necessary rigidity. Strips of platinum foil 0.001 in. thick, 12.5 cm. long and 0.5 cm. wide, having a median corrugation, form the anodes. Three electrodes are used in each cell, one anode in the middle and one cathode oil each side of the anode. These electrodes are connected to slotted alumi¬num terminals, in which they are held by contact pressure. The terminals are -in. rods, projecting 2 in. horizontally in front of the wall of the cabinet.; at the back the middle electrode (anode) is connected with one pole of the current, and the two outer ones (cathodes) with the other pole.

Nov 1, 1905

By S. T. L. Harrison, M. A. Fagan-Endres, M. D. Odidi

This paper investigated the ability of eight common hydrodynamic models – tanks in series (TIS); three compartmental model configurations (Comp-1, Comp-2 and Comp-3); advection dispersion (AD); piston exchange (PE); piston exchange-diffusion variant (PE-D) and piston dispersion exchange (PDE) – to simulate residence time distribution (RTD) data generated from tracer tests conducted on a packed bed composed of different size fractions of malachite ore. The chosen materials were packed into 0.1 m internal diameter columns to a depth of 0.155 m and drip irrigated at 5.11 L/ m2.h. The four size fractions tested were: 1 – 2 mm, 2 – 2.8 mm, 4.75 – 5.6 mm and 13.6 – 16 mm. Step-up tracer tests were conducted using potassium chloride. The results showed that an increase in the particle size of the malachite ore had little effect on overall bed porosity but resulted in significantly lower values of liquid holdup. Two of the monoporosity models tested, TIS and Comp-2, were the most affected by the changes in bed size fraction due to their inherent inability to cope with high degrees of non-ideal flow present in the larger particle systems. The dual porosity models performed relatively better with the dominant trend being a reduction in dynamic to total liquid holdup as particle size increased. Of all the models tested, the PDE and TIS models were the best and worst performers respectively, with R2 values averaging at 0.997 and 0.679 across all experiments respectively. Though the Comp-1, Comp-3 and PE-D models also performed well, the addition of the dispersion coefficient to take the axial spread of fluid molecules into account added a layer of complexity that allowed the PDE model to perform relatively better than the other dual porosity models. Keywords: Heap leaching, packing material, hydrodynamics, malachite, PSD, modelling

Jan 1, 2020

By W P. Darcey

Jabiru Metals completed a feasibility study on the Jaguar Base Metal Project in July 2005. The study was based on conventional truck haulage via a decline. Conveyor haulage was considered but not in sufficient detail to provide a meaningful comparison. The current study investigates the cost and productivity of alternative ore transport systems for the Jaguar project. The options considered are conventional underground truck, conveyor, road train, rigid frame truck, monorail haulage and shaft hoisting. Shaft hoisting was not considered in detail due to the high capital outlay for such a relatively short mine life of less than six years. This study goes beyond the common approach of evaluating haulage systems in isolation; it includes development costs, timing of ore production and costs associated with mine services as well as administration and milling costs. The results of this study indicate that the best haulage option for the Jaguar project is conventional truck using the Hitachi AH400 trucks. The net present value (NPV) for this option is A$8.13 million higher than the next best option namely the Kiruna E635 electric truck. The conveyor option has the lowest operating cost per tonne of ore but the longer development time negatively impacts on its NPV. The monorail option is considered impractical due to the number and length of trains required to achieve production targets.

Mar 21, 2011

By George A. Guess

The increasing demand for greater speed and more accuracy, in making daily assays of ores and products from mills treating material containing but very small quantities of lead and copper, has caused the older analytical methods to be supplanted by new ones devised to meet the needs of modern work. For " control" work in copper-analyses, I had, previous to the present equipment, introduced in my laboratory the ordinary electrolytic method, using hollow cylindrical electrodes; and with these I began a series of experiments in determining the lead-content of daily mill-samples and controls. The results, proving accurate and satisfactory, I then devised, with Mr. H. E. T. Haultain, a cheaper electrode than the ordinary jaCket-electrode, which costs from $15 to $20,—the expense of the older form making the installation of many units very costly. The form of cathode finally adopted as the most satisfactory, shown in Fig. 1, is cut from 0.001-in. platinum foil. It is 12.5 cm. long, and is divided into a blade 4 cm. wide and 6.25 cm. long, and a tongue 0.7 cm. aide and 6.25 long, the immersion area being 50 sq. cm. and weight 1.5 grams. The blade is first sand-blasted and then corrugated lengthwise, in order to impart the necessary rigidity. Strips of platinum foil 0.001 in. thick, 12.5 cm. long and 0.5 cm. aide, having a median corrugation, form the anodes. Three electrodes are used in each cell; one anode in the middle and one cathode on each side of the anode. These electrodes are connected to slotted aluminum terminals, in which they are held by contact pressure. The terminals are 5/16in. rods, projecting 2 in. horizontally in front of the wall of the cabinet; at the back the middle electrode (anode) is connected with one pole of the current, and the two outer ones (cathodes) with the other pole.

Jan 1, 1906

US 4,132,758-Leaching of copper sulfide ore using nitrogen dioxide as the oxidant A slurry of ore in sulfuric acid is contacted with a nitrogen dioxide-containing gas at a temperature below 11 5" C and a pressure of from atmospheric to 35 PSI, the slurry agitated, and the resulting nitric oxide from the slurry regenerated to nitrogen dioxide for reuse About 90% of the copper In the ore IS dissolved, and the leach solution is separated for further processing. This procedure is also useful for sulfide ores of silver, molybdenum, nickel, cobalt, and zinc T C Franklewicz and R E Lueders, assigned to Kennecott Copper Corp Jan 2, 1979 7 pp (423-27) Filed 1 1-30-77 (855,983) (Drawings below ) US 4,138,231-Wet-cleanlng of gases from the roasting of copper sulfide ore, zinc sulfide ore, pyrite, or arsenopyrite The gases are washed in dilute sulfuric acid circulating in a closed system, the wash water treated to remove arsenic, the washed gas condensed by cooling; and the condensate separated, purified of residual arsenic, and neutralized B G V Hedenas, J E Wiklund, T R H Johansson, and KA Melkersson, assigned to Boliden AB Feb 6, 1979 7 pp (55-71). Filed 3-30-77 (782,908) Priority Sweden, 4-9-76 (76/04,219) (Flow diagram at right ) US 4,148,862-In the acid-leaching of silicate-bearing calcined zinc sulfide ore, finely divided calcine is leached at elevated temperature with sulfuric acid, and additional calcine is added at an optimum rate to precipitate SI~ICIC acid in the same stage In an easily settling, readily filterable form Reactions take place at a silica concentration so low that the solution is not greatly oversaturated An anionic flocculant- may be added to the slurry immediately before the filtration step S. P Fugleberg and J T. I Poijarvi, assigned to Outokumpu Oy Apr. 10, 1979 4 pp (423-106). Filed 10-6-77 (840,041) Priority Finland, 10-8-76 (76/2880)

Jan 1, 1980

By T Suwa, S Ishida, J Xue, S Fuchida, H Shimada, Y Aoki, C Tokoro

Pyrite depression with prolonged pre-conditioning treatment in high salinity water has attracted much of researchers’ interest in recent years considering the increased utilisation of multiple stage flotation, closed water circuits, clay minerals, and sea water in flotation plants. In this study, the role of calcium (Ca)/magnesium (Mg) precipitates in stabilising the dissociative ferric hydroxy-xanthate (FHX), and its effect on modifying the balance of hydrophobic/hydrophilic species on the pyrite surface were primarily investigated. The total amount of extractable Fe-bearing species on pyrite concentrates and tailings after floatability test was quantitively determined using ethylenediaminetetraacetic acid (EDTA) extraction tests combined with inductively coupled plasma optical emission spectroscopy (ICP-OES). A more evident accumulation of extracted-Fe in pyrite concentrates rather than it in pyrite tailings was observed at both pH 9 and 10.5 when pyrite was pre-conditioned in Ca/Mg-bearing solutions for 360 min. Fourier transform infrared (FTIR) spectroscopy showed the main xanthate derivatives changed from di-xanthogen (1155 cm-1 ) to FHX (1167 cm-1 ) on the oxidised pyrite samples that were preconditioned in Ca/Mg-bearing solutions. Scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) suggested the preferential accumulation of FHX upon secondary Ca/Mg-bearing precipitates as reflected by the higher Fe/S ratio together with the decrease of O element herein after xanthate conditioning. Although the hydrophilic secondary Ca/Mg/Fe-bearing minerals on the pyrite surface generally deteriorate pyrite’s floatability, the upper section of these secondary hydrophilic aggregates is partially covered by FHX alongside with further multilayer-adsorbed di-xanthogen. The precipitated Ca/Mg-bearing precipitates promotes the immobilisation of dissociated FHX derived from the reaction among iron oxyhydroxides and xanthate anions upon the localised secondary Ca/Mg/Fe-bearing minerals via acid–base complexation. Therefore, this phenomenon alleviates the hydrophilic modification of secondary Ca/Mg/Fe-bearing minerals to pyrite considering the immobilised FHX upon localised precipitates shows a slight hydrophobicity, and meanwhile, the upper FHX benefits the multilayer adsorption of di-xanthogen via the interaction among their inner hydrophobic alkyl chains.

Aug 24, 2022