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By M. F. El-Demerdash

The activity distribution diagrams for different species in aqueous systems are developed. Computational method may be considered as an extension of the Activity-Term method introduced by the authors to construct EH-pH diagrams. In the Activity-Term method, all activities of different species are evaluated before deciding the most stable one. In the present study, a factor is assumed to allow for the conservation of the element. At any point, the total concentration of all species should contain only the input m moles of the element (elements) considered. This approach is applied to Zn-, 5-, and Zn-S-H2O and activity distribution diagrams are plotted as a function of pH, at different potential levels and at different temperatures.

Jan 1, 1990

By Richard Franchot

IN the inevitable conquest of the blast furnace by metallurgical science in the solution of the problem of how to make more and better iron or to burn less coke, or both, it is highly desirable first to find out why the efficiency of the furnace generally is no better than it is. The immediate need would seem to be a theory to account for the existing facts. Explanation for the quantitative results obtained in current practice has been strangely lacking. One reason for this may be found perhaps in the custom of think-ing of efficiency in terms of coke consumption. Before efficiency can be explained there should be a fairly exact knowledge of what it is. A statement of the pounds of coke used per ton of iron made may have value in indicating comparative results in smelting similar ores with similar cokes, but it tells very little of the efficiency of the operation. When the materials are different, one practice burning 1800 lb. may be less efficient than another using 2000 lb. A better measure is the pig and slag per unit of coke. What is needed is a specific description of efficiency as a' definite quantity having an exact meaning. Such description is afforded by expressing efficiencies in terms of the respective proportions of the fuel energy absorbed in and chargeable to the various actions known to be -taking place in the furnace. Concretely, the energy value of a pound of coke having 85 per cent carbon blown with air heated to 1200° F. is about 7650 lb.-cal. (13,770 B.t.u.). And the work done in smelting a pound of average iron from hematite, comprising reduction and melting with production of a half pound of free running slag from an equal weight of limestone,

Jan 9, 1926

By Wei Huang, Anh V. Nguyen

"Potash flotation is an industrially proven success of flotation of soluble salts, but its collector adsorption mechanism remains elusive. In this paper, specific ion effects in NaCl-KCl flotation with carboxylate collectors were investigated. Flotation recovery and contact angle were determined as a function of brine composition of NaCl and KCl. The experimental results have shown that wettability of KCl and flotation of the soluble salts with laurate collectors were dependent on brine ion composition. Specifically, adding Na+ to brines decreased hydrophobicity of KCl crystals and their flotation recovery. Both KCl and NaCl could be floated with laurate collectors. However, flotation of NaCl was greatly enhanced by adding K+ to brine whereas flotation of KCl was significantly suppressed by the presence of Na ions. The decrease in KCl recovery upon adding Na+ is attributed to the counter-ion binding in the pulp. The flotation recovery enhancement of NaCl in the presence of K+ is explained by two effects: 1) increasing K+ concentration leads to a better dispersion of collector colloids in the pulp and 2) K+ enhances the collector adsorption at NaCl crystal surfaces. The water affinity matching rule can explain the specific ion binding behaviors and supported by the SFG spectroscopic results.INTRODUCTIONPotassium is an important fertilizer. Its primary source comes from potash ores, which are a mixture of sylvite (KCl), halite (NaCl) and many other complex double salts such as carnallite (KCl·MgCl·6H2O), alkali nitrates such as KNO3 and NaNO3, and sulfates-langbeinite (2MgSO4·K2SO4) with water-insoluble minerals such as clay and carbonate minerals. Previously, these salts were recovered with a lengthy hot leaching method, with further crystallization of potassium salts from saturated saline solutions. Selective flotation has been preferred since 1940s. Various collector adsorption mechanisms have been proposed soon after the industrial introduction of potash flotation. These include the formation of the insoluble compound model (Halbich, 1933; Singewald, 1961), an ion exchange model (Fuerstenau and Fuerstenau, 1956), a heat of solution model (Rogers, 1957), the surface hydration model (Schubert, 1988), the surface charge model (Roman, 1966; Miller et al., 1992), the interfacial water structure model (Hancer and Miller, 2000) and the colloid adsorption model (Leja, 1983; Burdukova and Laskowski, 2009). Most of the early exercises attempting to propose a unified rule on collector adsorption mechanisms can be seen as heroic endeavors due to the consideration of a vast number of salts in the pulp including alkali halides, nitrates, and sulfates, even the practically insoluble heavy earth metals. Additionally, several types of surfactants with different polarization features and alkyl chain length have been employed. As for the recent models, due probably to the preferential application of long chain amines as collectors in industrial potash flotation, most researchers are only devoted to collectors with low polarization features like amines and sulfonates (Hancer and Miller, 2000; Du et al., 2014). Collector adsorption mechanisms are therefore proposed based largely on a neglect of carboxylates as collectors. However, carboxylates remain an important collector type in soluble salt flotation systems where both salt minerals can be floated using anionic collectors and cationic collectors. Fatty acid type collectors are still one of the widely used collectors for soluble salt flotation and also one of the first to be applied on an industrial scale for the separation of potash ore (Hernáinz et al., 2003; Titkov, 2004). Here we examine some recent models that are relevant to our study to reveal a long neglected specific ion binding effects in potash flotation."

Jan 1, 2016

By L. E. Mylting

Modern ash handling systems exist in considerable numbers and a great deal of design and operating experience has been accumulated, It is the endeavor of this paper to point to a number of frequently recurring problems, A general appreciation of these problems will be helpful in both design and operation of systems. The light fly ash and the heavy bottom ash present different problems, and each will therefore be treated separately. Fly ash is collected in the ducting from the furnace to the stack and beneath the mechanical and electrostatic dust collectors. The greatest amount of dust is collected beneath the mechanicals and electrostatics. Hoppers are generally provided as integral parts of the collector. Suitable valves and piping are connected to these hoppers for removal of the dust. The size and shape of these hoppers are important factors in determining frequency of handling and the capacity of the system.

Jan 1, 1958

By D J. Brake

There are many sources of gas in underground mines including development and production blasting, strata gases, spontaneous combustion, diesel equipment, chemicals used for a wide range of functions, welding activities and fires.It is only in relatively recent times that electronic gas monitors (or detectors) have become both safe and affordable for routine use.In modern mines, gas monitors should be in daily use by the ventilation department as well as blasting re-entry (or clearance) crews, and are often used by drilling crews, shift supervisors, hygienists and mine rescue or fire fighting crews.When first released, electronic gas monitors needed to be sent off-site periodically for calibration at a suitable accredited laboratory. Between calibrations, their accuracy was unknown. More recently, ‘bump testing’ and field calibration has become possible on the mine site, improving both reliability and safety as well as reducing the total number of gas monitors that need to be in use.There has been almost an overwhelming increase in the number and sophistication of gas monitor features in recent years. This paper reports on a case study into the key criteria that ventilation practitioners should be aware of with respect to the specification and selection of the most recent gas monitoring systems, and recommends good practice for site-based operation and calibration.CITATION:Brake, D J, 2015. Specification and selection of hand-held gas monitors (detectors) for underground mines, in Proceedings The Australian Mine Ventilation Conference, pp 143–154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By V. Svalbonas

Presently the U.S. mining industry is very conscious of costs. It is timely, therefore, to review the dominant specifications used in the industry for procuring large size-reduction equipment. These are compared with other specifications and procurement methods, such as ASME and DOD, using the criteria of resulting costs, safety/ quality, and fitness-for-service.

Jan 1, 1987

By J. E. Gray

Before specifications are discussed it may be well to define the term "Mineral Aggregates." Professor K. B. Woods (1) defined "Mineral Aggregate--An aggregation of sand, gravel, crushed stone, slag, or other material of mineral composition used in combination with a binding medium to form bituminous and portland cement concrete, macadam, mastic, mortar, plaster, etc., or alone as in railroad ballast, filter beds, and various manufacturing processes, such as fluxing, etc. " This definition is too all inclusive for the purposes of this paper; therefore, this discussion will be confined to specifications for natural aggregates which means sand and gravel and crushed stone, and limited primarily to coarse aggregate which is aggregate larger than one-quarter inch in size. To the uninitiated, this may seem to be a very limited subject on an unimportant material. However, aggregates are essential in all types of construction. The tonnage and value of these two aggregates produced in the United States during 1959 as reported by the Bureau of Mines were as follows: Sand and Gravel 729,895,000 tons valued at $728,527,000 Crushed stone 581,721,000 tons valued at $824,411,000

Jan 1, 1961

By M. Jack Snyder

The problem of effective utilization of fly ash has been given wide attention for a number of years. Although the effort devoted to the problem has led to some applications of demonstrated usefulness, the full utilization of fly ash has been held back by lack of concerted research and development activity, by lack of effective dissemination to potential users of fly ash of the knowledge that is available from laboratory and field studies, and by the obvious variability of the product. Because of the variability in fly ash from one power plant to another and from time-to-time in the same plant, specifications have been set up defining compositional or property limits within which a fly ash must fall to be used in certain applications. This paper discusses the bases for such specifications and examines them in the light of recent research on the characterization of fly ash. Other limitations and restrictions on the use of fly ash and what is being done to overcome them are also discussed.

Jan 1, 1968

By R. Tanaskovic

Unfavourable climatic conditions in stopes are of significant economic and social importance due to the following reasons: - Working effect is much lower leading to decreased output and work productivity disregarding implementation of mechanization. - Manpower operating capability decreases much faster under unsatisfactory climatic conditions. Under normal climatic conditions a workman would expend much less effort in line with a shorter effective time for the achievement of identical production effects since the work would be more efficacious. The objective of study of problems and climatic conditions is to make the working environment in mines suitable for normal development of operations. Lowering of mining works to increasing depths and winning of a growing number of small orebodies over a broad area makes the problem of creating suitable climatic circumstances more complex. Mining costs are growing due to bench conditions in line with decreasing metal content in the ore, so frequently the investments required for creating favourable climatic conditions represent, in addition to the selection of mining technology, a very important parameter when making decisions regarding exploitation. As known, the basic factors affecting climatic operating conditions in mines-are: temperature, humidity and speed of air flow, implying that the climatic operating conditions are closely related to mine ventilation. Usually, the concept of unfavourable climatic operating conditions includes increased mine air temperature and humidity and low air flow velocity so that heat exchange between human organism and the working environment is impeded or reduced to minimum. Metal mines in Yugoslavia are characterized by the existence of a large number of active faces - stopes and horizons and lowering of mining operations to increasing depths, so that face ventilation solutions are more and more complex. Since its foundation (1961), our Institute is engaged in investigation of factors influencing climatic circumstances improvement of calculations for air distribution and distribution control in complex ventilation networks and study of problems related to ventilation of large volume and irregular configuration faces, as well as application of gained knowledge in our mines. The paper presents the knowledge and experience gained in the case of Lead and Zinc Mine "Trepca" - Stari Trg.

Jan 1, 1980

By Y. M. Shneerson, P. V. Zaytsev, I. V. Fomenko, M. A. Pleshkov

A thermodynamic description of the equilibrium in liquid and gas phases under specific conditions of refractory gold pressure oxidation was generated using the HKF theory. The gold behavior was considered at 190-225°C in the presence of 1-100 mg/L of chloride ion, and under oxidationreduction potential (ORP) of +700 to +1030 mV. The calculations show that the predominant form of gold(I) occurrence is [AuOH]° compared to [AuCl2]?. High ORP favors the formation of [AuCl4]? as a predominant form of gold(III). It is noted that this complex is responsible for the gold losses buildup during POX. Laboratory test results for double refractory concentrate POX are shown. The combined negative effect of (i) organic carbon of the concentrate and (ii) dissolved chlorides in POX slurry on gold recovery is demonstrated. The effects of carbonate blending to the POX feed concentrate and incomplete oxidation of sulfides on POX performance were studied. The pilot tests results of continuous pressure oxidation are also shown and generally confirm the laboratory results and theoretic dependencies. A comparison of the experimental data with the results of thermodynamic calculations is made. As a result of current research, an effective process for POX treatment of carbonaceous sulfide concentrates in the presence of chlorides was developed.

Jan 1, 2014

By I. Ruiz Bustinza, L. F. Verdeja, Daniel Sbarbaro, R. Parra, J. Mochón

The oxidation of sulfides is a complex process involving gaseous products and intermediate species given rise to emission and absorption spectra which carry out important information about the reaction process. This information could be used for on line monitoring of pyrometallurgical reactor if the appropriate sensors were available. We present in this paper an analysis of the concept that has been successfully applied in iron and steel making industry, as well on fuel combustion control, where the spectra measurement gives the possibility for online monitoring and automatic control of high temperature processes. This concept has not been widely applied in the nonferrous pyrometallurgical primary production. The design of new sensors is discussed from the analysis of spectra measurements during flash combustion of copper concentrates at laboratory scale.

Jan 1, 2015

By Ronald W. Marrs

Kimberlite contains a unique assemblage of minerals and exhibits a characteristic pattern of spectral reflectance in the visible and near-infrared wavelength region. This spectral pattern is readily discerned in well-exposed kimberlite outcrops, but becomes increasingly difficult to identify when outcrops are partially covered by vegetation or soils derived from non-kiaberlitic materials. Detection of poorly exposed kimberlite diatremes is possible using multispectral imaging techniques in which spectral bands are chosen to optimize contrast between he kimberlitic soils, non-kimberlitic soils and vegetation. Careful processing of the multi-spectral data is also essential in order to separate the spectral signature of kimberlite from the signatures of other components of the scene.

Jan 1, 1984

By Lifeng Li, Jhon Silva-Castro

"Signature Hole Technique is one method to assess the vibration waveform of a production blast.Methematically, it is the convolution between a prior measured waveform of a single blast hole (signature) and a given time delay sequence (comb function). Being an advantage, the inverse operation of convolution, known as deconvolution, can be used to estimate the signature."

Jan 1, 2017

By J. N. Baloyi

"In atomic emission and atomic absorption spectrophotometry, the sample is heated to a high temperature and thereby decomposed into atoms and ions that absorb or emit visible or ultraviolet electromagnetic radiation at energies characteristic of the elements involved. The flame test is a very simple form of this technique. The yellowing of a flame by the addition of salt, for example, occurs because the sodium in salt emits strongly in the yellow portion of the visible spectrum. These methods are especially useful for low concentrations of metallic elements in both qualitative and quantitative analysis.Interference on Iep-OES has not always been considered a serious problem, especially in the beginning, when compared with Atomic Absorption Spectroscopy. This was due to the euphoria created by the new technique. It meant that criticism was subdued. The Iep was vastly superior to the Atomic Absorption technique, that the interferences suffered by the Atomic Absorption technique dwarfed the little interferences suffered by the rep-OES technique. This is how rep-OES has had a reputation as an interference free technique."

Jan 1, 2014

By E. F. Paski

Geological materials are likely the most complex and challenging substances to quantitate by ICPOES (inductively coupled plasma optical emission spectroscopy). For complex materials having widely varying compositions, spectral overlap interferences govern detection and quantitation limits attained by ICPOES based analytical methods.

Jan 1, 1993

By J. E. Hawley

Abstract Spectrographic methods for the analysis of minor constituents such as platinum-group metals, gold, silver, and silica in palladium and platinum refinery sponge are described. These involve the conversion of the sponge metals to the black form by reduction with high purity aluminum filings in either acid or alkaline media. Standards of known composition are prepared in the same manner from either refinery or spectrographically standardized sponge metals. Samples of the black metals are mounted in pellet form and a multisource spark discharge used for excitation. The range of concentrations of impurities studied are those common to refinery samples. Excellent reproducibility of intensity ratios using major constituents as internal standards, is demonstrated and two methods have noted by which the accuracy of the procedures are shown to be of the order of 3 per cent, on the basis of synthetic preparations. Introduction During the past two years an investigation has been carried out in the Spectrographic Laboratory, Queen's University, to determine the suitability of modern spectrographic techniques for the precise analysis of the platinum-group metals palladium, platinum, rhodium, iridium, and ruthenium in the form of refinery sponge analyzing about 99 per cent of the major constituent.

Jan 1, 1951

By W. L. Ott, C. L. Lewis

"AbstractA technique is described for preparation of palladium sponge and for spectrochemical analysis of the metal in this form. The precision and accuracy of the method are discussed. Analyses are compared with previous spectrochemical analyses of palladium in the black form. Good agreement was found in the two sets •of results and it is concluded that they are more reliable than wet chemical .analyses of the same material.IntroductionFOR SEVERAL YEARS the problem of platinum metal analysis by spectrochemical methods has been under investigation at the Spedtrographic Laboratory, Department of Geological Sciences, Queen's University. The problem, briefly -stated, is as follows: Samples of platinum, palladium,-rhodium, ruthenium, and iridium are received as fine metal powders, called sponge. Direct spectrographic analysis of this material has not been found satisfactory due to its heterogeneity •as regards contaminant metals, which may be present up to a total of one per •cent or more. Further-more, spectrographic standards are difficult to obtain and difficult to prepare accurately by adding weighed portions of contaminant metals to the sponge. The fact that •contaminant metals in original samples are probably alloyed with the major constituent is a further difficulty since complete fusion of these refractory metals proved impractical in the present case as a means of standard preparation. It •has, therefore, been found most satisfactory to dissolve the metals, prepare standards by addition of solutions of contaminant metals, and to reduce both standards and samples to a homogeneous form. A previous paper, by Hawley, Wark, Lewis and Ott (2) dealt with a method for spectrochemical analysis of platinum and palladium in their black form. Since completion of research on the black technique, the possibility of analyzing palladium accurately in its sponge form has• been investigated."

Jan 1, 1953

By W. L. Ott, J. E. Hawley, C. L. Lewis

"IntroductionTHE APPLICATION of spectrochemical analysis to metals of the platinum group was advocated by Harvey (3) as follows: ""The spectra of the platinum group metals have been studied less than many of the more common metals. The rarity of occurrence of these elements makes the analysis relatively unusual. Potentially, the analysis of this group is an excellent application of spectrographic methods, particularly in contrast to the tedious chemical procedure"".Wichers (8) divides platinum-metal analysis into three broad divisions as follows :( 1) The detection and estimation of these metals in other materials, e.g., ores, where the amounts present are very small.(2) The detection and estimation of impurities in the refined metals themselves ....(3) The analysis of alloys of the platinum metals .....The present paper deals with the second division: analysis of refined rhodium.Research on spectrochemical techniques for determination of trace contaminants in refined platinum metals was begun at Queen's University in 1949, under the supervision of Professor J. E. Hawley. Since 1953, the work has been continued in the Metallurgical Laboratories of Falconbridge Nickel Mines, Limited. Techniques for spectrochemical analysis of refined platinum and palladium have been published ( 4, 5). A technique for analysis of refined iridium has been developed but not yet published."

Jan 1, 1955

By H. Huang, Y. Takasaki, R. N. Gow

"The presence of enargite (Cu3AsS4) is problematic in gold processing not only because it is environmentally hazardous due to its arsenic content but also because it is refractory, causing both cyanide and oxygen consumption to increase. Selective leaching and treatment of the arsenic would prove advantageous prior to applying conventional gold leaching methods. The reactivity of enargite samples from Butte in Montana and Quiruvilca in Peru were spectroelectrochemically studied under alkaline conditions – pH range of 8-13 – using Raman spectroscopy and cyclic voltammetry. Raman spectra of the surface were collected during and after potentially cycled voltammograms in order to determine and compare surface species against theoretical EH-pH diagrams constructed from mass-balanced thermodynamic calculations using STABCAL software. Under slightly oxidizing conditions, covellite (CuS) peaks were found in a short matter of time, above ~100mV vs. SHE for pH 9-13, suggesting arsenic leaching specifically occurred. At longer conditioning times, elemental sulfur was observed and tended to passivate the surface. The presence of elemental sulfur suggests that copper was eventually leached from the surface. By operating above pH 12, under slightly reducing conditions near -300mV vs. SHE, arsenic can be selectively leached as thioarsenate (AsS4 3-) or thiosulfate (AsO4 3-) without sulfur formation.IntroductionEnvironmental limitations on the pyrometallurgical processing of ores and concentrates bearing arsenic and other hazardous elements often outweigh those in hydrometallurgical processing, particularly when minerals like enargite (Cu3AsS4) are present. The hydrometallurgical processing of enargite-bearing materials can be broken down into two categories: the co-dissolution of arsenic and copper under acidic conditions, and the selective leaching of arsenic under alkaline conditions. The selective leaching of arsenic would preferably leave behind copperrich sulfide phases, typically chalcocite (Cu2S) and covellite (CuS), which then become more amenable to conventional copper (and gold) processing. Furthermore, selective leaching often employs sulfide (S2-), bisulfide (HS-) or polysulfides (Sx 2-) to first extract the arsenic as AsS4 3- and AsS3 3- (Delfini et al., 2003; Anderson and Twidwell, 2008; Tongamp et al., 2010a,b). However, hypochlorite leaching (Viñals et al., 2003; Curreli et al., 2005; Mihajlovic et al., 2007), ammoniacal leaching (Gajam and Raghavan, 1983), and finegrinding to mechanically activate the enargite surface (Balaz and Achimovicova, 2006) have been investigated to increase the normally slow reaction kinetics. Because gold ores are becoming more refractory due to increasing arsenic contents as a result of enargite, these methods are being examined more closely by the gold-mining industry."

Jan 1, 2015

By H. Huang, R. N. Gow

Acidic treatment of enargite (Cu3AsS4) dissolves both arsenic and copper from the mineral and then attempts to separate them in the leach solution. The reactivity of enargite was examined in acidic to neutral solutions, over the pH range 1-7, to determine a potential range for co-dissolution. Enargite mineral samples from Butte, MT and Quirivilca, Peru were used as working electrodes in a cyclic voltammetry corrosion cell setup, which were then cycled multiple times over -1000 to 1000 mV. Surface reactions and transitions were characterized using in-situ Raman spectroscopy, which were then compared to updated EH-pH diagrams for the copper-arsenic-sulfur-water system from a previous study done under alkaline conditions. The region of co-dissolution is limited to > 600 mV vs. SHE and pH < 1 under the proposed diagram.

Jan 1, 2014