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By K. A. Natarajan, M. N. Chandraprabha

Selective separation of minerals from complex sulphide ores is a challenging task and it is often difficult to get commercially acceptable individual concentrates by conventional selective flotation using inorganic collector reagents. Microbially-induced mineral beneficiation has proved to be more effective, economically viable and an environmentally benign process for the effective separation of various minerals. Applications of microbially-induced mineral beneficiation are demonstrated in this paper with respect to beneficiation of complex multimetal sulfides. The role of adapted microorganisms and bioreagents in the beneficiation of complex sulphide minerals are also illustrated.

Jan 1, 2009

By Ellis Thomson

The microscope is now used extensively not only in the examination of solid ore but also in the determination of fragmental mill products. It has therefore become a matter of paramount importance to be able to mount and polish fragmental as well as solid specimens in the easiest and most efficient way, so that the minerals present may be readily determined. In the case of the solid ore the ordinary mount of plasticine set on a glass or metal slide serves for most practical purposes. An improvement on this is furnished by the small brass container inside of which the specimen is mounted in a cementing medium of sealing wax. The latter is the method in use at Harvard University. It has the advantage of uniform height, thus obviating the necessity of a slide of any sort. It is also easily catalogued as the brass holder may be stamped with a convenient series of letters and numbers that will serve as a label. Other advantages of this type are the ease with which any particular part of the section may be re-located, the excellent storing facilities afforded by mounts of uniform size, and the possibility of polishing ten or a dozen sections at the same time by means of a holder which is placed over the polishing wheel, is geared with it, but revolves the opposite way.

Jan 1, 1926

By Phillip J. Mackey, Susumu Okabe

Copper mining and smelting has been carried out in Japan for over 13 centuries and in fact stretching back into antiquity. In 1889, the first electrolytic copper refinery in Japan based on Elkington’s principles was started by Furukawa Mining at Honjyo in downtown Tokyo based on the multiple or parallel system. Within two decades, a number of other copper refineries had begun operation. Interestingly, but perhaps not surprising given Japan’s long history of copper production, this first refinery in Japan commenced just ten years after the first refinery in the USA (1879), and not long after the first plants in Europe. By 1935, as a result of growth in copper demand, there were six domestic copper electro-refineries in Japan with an installed capacity of 97,800 tonnes/a, while actual production was 71,200 tonnes/a. Since about 1932, the majority of these plants were based on the more common parallel or multiple system. In 1946, just after World War II, domestic production capacity had dropped considerably to 29,000 tonnes/a, however with reconstruction, capacity and production expanded rapidly, with production reaching 81,000 tonnes/a in 1955, 187,000 tonnes/a in 1960 and 307,000 tonnes/a in 1965. The introduction of the first refinery and the early ones that followed and subsequent developments are discussed in this paper. The major technical achievements during the high growth period from 1945 to 1963 included: the use of fire- refined anodes; the introduction of newly-developed rectifiers; the introduction of lead-lined or vinyl-lined concrete cells; improvements in the electrolyte heating system; application of improved anti-corrosion materials and the introduction of heat-insulating surface coverings. In 2018, Japan’s refined copper production totaled 1,595,000 tonnes of copper, with Japan ranking third in the world after China and Chile. INTRODUCTION In 2018, Japan’s refined copper production totalled 1,595,000 tonnes of copper and Japan ranked third in the world for refined copper after China and Chile (Wood Mackenzie, 2019). There are now eight copper refineries in Japan which provide Japan’s production of refined copper. These plants are listed in Table 1 (Wood Mackenzie, 2019), also showing the production trend since 2013; in general, production over this period has been relatively steady. The Toyo plant is now the 7th largest copper refinery in the world after several large plants as rated by capacity in China, Russia and India (ICSG, 2019).

Jan 1, 2019

By K D. Conroy

For the past year, Lowphos Ore Ltd. has been operating two desliming hydroseparators on a fully automatic basis. Automatic operation is achieved by sensing the position of the silica-magnetite interface and automatically controlling the jet water addition to maintain a desired interface position. The system further provides automatic control of the underflow pump speed in order to assist in maintaining interface position when an <Ore change occurs. Interface position is maintained at 12 inches below the surface and is -controlled within plus or minus one inch. Metallurgical unit recovery is held above 98.5 per cent, and a 10 to 12 per cent increase in concentrate grade is normally achieved.

Jan 1, 1963

By Z. Luo, China University of Mining & Technology, C. Duan

"The magnetic separation removal rate of pyrite could be improved effectively by increasing the susceptibility of pyrite. The electromagnetic characteristics and absorption response performance of high-sulfur fine coal were studied in strengthening the susceptibility of pyrite. In the process of treating the sample through the microwave, electromagnetic energy could be converted into heat energy due to dielectric loss and magnetic loss. The RL(dB) was evaluate the performance of absorption response of coal. The microwave improved the susceptibility was in ultra-high frequency region, which is the most natural resonance. The absorption fine coal to microwave was strengthened and microwave energy was improved by adding the magnetite powder with double loss characteristics as the microwave absorber. The dielectric properties and permeability characteristics of the fine coal trend were investigated by maxing magnetite powder. The microwave absorption in different coal thickness was surveyed through the reflection of energy loss.INTRODUCTIONMicrowave desulfurization is one of the most important research directions (Haque, 1999; Makul, Rattanadecho, & Agrawal, 2014; Su, Tang, Zhang, Jing, & Bai, 2014). The working principle of microwave absorption response can be briefly described as the interaction of the sample with microwave energy, which will result in the microwave energy converting into heat energy loss (Keangin & Rattanadecho, 2013). For specific samples, the polarization effect includes multiple polarization mechanisms(Meikap, Purohit, & Mahadevan, 2005). Different polarization mechanisms have different occurrence time and dominant mechanisms. Meantime, energy consumption will be occurred during the process of polarization effect (Chelgani & Jorjani, 2011; Rowson & Rice, 1990) . The absorption of microwave energy in the fine coal is a process of electromagnetic response (Znamenácková, Lovás, Mockovciaková, Jakabský, & Briancin, 2005). Microwave transfers the electromagnetic waves into the heat energy by microwave dielectric loss and magnetic loss for achieving the absorption of microwave energy in the treatment of samples (Lee, Kim, Kim, Chung, & Kim, 2004). The additive magnetic medium is Fe3O4 belonging to microwave energy absorber of double loss medium (Uslu, Atalay, & Arol, 2003)."

Jan 1, 2016

By Jr. Fackler

The ionization potentials of gaseous Group 11elements are similar, with Au(0) being 1.5 eV greater than the next highest member of the group, Cu(0). The ionization potentials are all very much greater than the alkali metals, making these ?coinage? elements rather unreactive to chemical oxidation. Ionization from the first oxidation state shows a different pattern, with Ag(I) being the most difficult of the Group 11 ions to lose an electron. Gold(I) is noble and only normally oxidized in the presence of strongly coordinating ligands such as thiols or cyanide. Gold(I) compounds are 2-, 3- and 4- coordinate, with 3-coordinate species generally showing visible photoluminescence under UV excitation. Dinuclear Au(I) compounds with strongly coordinating S or C ligands can be oxidized to form isolable metal-metal bonded Au(II) compounds which are often readily isolable. Many have been structurally characterized. T he ease with which electrons are lost from closed shell dinuclear sp ecies (with anti-bonding M-M interactions) increases when metalmetal bonded compounds are formed. T his observation was made by our group with oxidative-addition studies of dinuclear gold(I) ylide complexes. It was superbly demonstrated recently by Cotton?s group who reported the isolation and characterization of a dinuclear closed shell transition metal species which is more readily oxidized than cesium. Trinuclear Au(I) pyrazolates, TR(pz), carb eniates, TR(carb), and benzylimidazolates, TR(bz), are well known and undergo electron loss through oxidative addition forming Au(I,III) mixed valence species and ultimately trinuclear Au(III) species. Au(II) species are absent from isolation in these oxidations. These carbeniates and benzylimidazolates also are excellent bases for metals ions such as Tl(I) and Ag(I). The acidic, neutral trinuclear compound [Hg(C6F4)3]3 also interacts with these bases. We have also shown that the neutral organic pi acids C6F6 and TCNQ form stacked pi-acid pi-base products with the trinuclear Au(I) compounds. In this paper, the structure of the octafluoronaphthalene acid-base product will be described. It displays a feature not observed previously in that the product is photoluminescent with a bright yellow emission. The 3.5 ms lifetime is very long and reminiscent of the long lifetimes observed by Balch for the stacked methyl,methoxy Au(carb). The electrochemical oxidation of tetragold(I) clusters, [Au4(form)4] have been studied in 0.1 M Bu4NPF6/CH2Cl2 at Pt working electrode at different scan rates. Three waves are obtained at 0.75, 0.95, and 1.09 V vs Ag/AgCl at scan rate 500 mV/s. The potential of the three reversible waves is independent of the scan rate in the range 50 mV/s to 3 V/s. The current at the third wave is larger than those at the first two waves. These tetranuclear species app ear to be effec tive catalyst precursors for the oxidation in air of CO. Introduction. The electronic structural relationships of the coinage elements and the alkali metals are similar in the sense that each have a [closed shell]ns1 configuration, yet their ionization energies (Table) and chemistries are clearly vastly different. The Group 11coinage elements have an underlying nd10 level immediately below the ns1 level. Unlike the alkali elements, ionization leaves the filled d electron shell the next accessible for further ionization. The coinage elements are all relatively ?noble?, much less reactive to environm ental conditions than the alkali metals. With the coinage elements, oxidation becomes very much dependent upon the types of ligand s availab le to bo nd to the ionized state.

Oct 1, 2003

By M. H. Colebrook

Nickel laterites contain about 70% of all continental or terrestrial nickel resources; therefore the recovery of nickel from lateritic ores has large economic significance. The processing of lateritic ores involves the preparation and movement of concentrated aqueous suspensions. However due to complex characteristics and non-Newtonian properties, ranging from shear-thinning to shear-thickening and from thixotropic to rheopectic, a basic understanding of the flow behaviour must be developed. This understanding will assist in the development of new plants and the operation of existing plants. The work in this paper involves the characterization of three ore types from the Vermelho ore deposit to categorize them as rheologically simple to complex. Rheological testing was also conducted on pure mineral samples that represent the main minerals in these samples. The results show that the rheological properties of the ore types can be related to the surface properties and physical characteristics of the main mineral constituents.

Jan 1, 2006

By E. Viljamaa

In this research, earlier developed information integration method and novel web technologies are applied to intensify infrastructure construction process control. The applied method uses semantic methods to integrate scattered information that is later on exploited by process management using state-of-the-art web technologies. The applied method and web technologies not only improve the process management situation awareness by integrated up-todate multi-source process data but also provide platform independent access and visualization tool for process data. Utilization of such technologies potentially lead on cost savings, make processes safer and also more environmentally friendly. The integration method also enables intelligent queries to the integrated data making possible to use machine based inferring to the data.

Aug 1, 2013

By Lang Tao, Jun Wang, Wei Xiao, Wenqing Qin, Pan Cao, Guanzhou Qiu, Key Lab of Biohydrometallurgy of Ministry of Education, Central South University

"The effect of metal cations on the rutile flotation using styryl phosphoric acid (SPA) as the collector was investigated by micro-flotation test, bench scale flotation test, zeta-potential measurements and adsorption measurements. The micro-flotation results indicated that Fe (?) and Al (?) ions in low concentrations had obvious activation on the rutile flotation, and Pb (?) ions in low concentrations had smaller activation of rutile, but Fe (?), Al (?), Pb (?), Ca (?) and Mg (?) have strong inhibition of rutile flotation in high concentrations. The bench scale flotation results indicated ethylene diamine tetraacetic acid (EDTA), boracic acid, and sodium hexametaphospate can decrease the metal ions concentrations, and increase the recovery of rutile flotation. Adsorption measurements and zeta-potential measurements revealed that Fe (?), Al (?) and Pb (?) ions were adsorbed on the rutile surface, and had interaction with SPA. But when these ions concentration were over the largest adsorption capacity, residual metal ions could occur chemical reaction with SPA.INTRODUCTIONRutile is one of the favored minerals for production of titanium dioxide white pigment, primarily through the chloride manufacturing process (Stanaway 1994; Hou et al., 2013) However, the majority of rutile ores belong to refractory ores, while flotation is one of the most efficient methods to separate fine rutile from gangue (Dolbear et al., 1937). With the flotation development, many effective collectors were successfully applied in the oxide ore. Many reviews have indicated that organic phosphonic acid collectors showed good selectivity on oxide ores such as ilmenite and rutile (Bulatovic & Wyslouzil 1999; Liu & Peng 1999).It is inevitable that many types of metal cations are present in ore pulp. These metal cations significantly influence the flotation of minerals. Liu et al. (2015) showed that Ca2+ and Mg2+ could improve the floatability of spodumene at pH 12.5 and 10.0, respectively. The authors proposed that Ca2+ and Mg2+ ions readily form hydroxy complexes (CaOH(l) and MgOH(l)) and precipitates as (Ca(OH)2 and Mg(OH)2) in strongly alkaline solutions. Fan and Rowson (2000) investigated the effect of Pb(NO3)2 addition as an activator on ilmenite flotation and showed that it could improve ilmenite floatability. The addition of Pb(NO3)2 resulted in an increase of ilmenite zeta potential in both weakly alkaline and acidic aqueous solutions. Mehdilo, Irannajad, and Rezai (2015) studied three kinds of ilmenite of different origins and discovered that both Mg and V had a negative correlation with ilmenite flotation, while the Mn content seemed to correlate positively with flotation efficiency. A number of studies have also showed that Fe3+ can improve the floatability of ilmenite (Fan et al., 2009; Nuri, Mehdilo, & Irannajad, 2014)."

Jan 1, 2016

By D. A. Beattie

Three novel dextrin polymers of varying functional group chemistry but similar molecular weight have been used to depress talc in single and mixed mineral studies. The mixed mineral system was a model sulphide ore consisting of talc, pentlandite, and chalcopyrite. Adsorption isotherms for the three polymers on both valuable and gangue mineral phases were determined to give initial clues as to the ability of the polymers to depress talc. Flotation testing revealed a distinct hierarchy of effectiveness of the polymers in the depression of talc in the single mineral system (MP Dextrin > CM Dextrin > Dextrin TYM), reflecting the observed adsorption affinity and adsorbed amount of the polymers on talc. However, a different order of effectiveness was observed for talc depression in the mixed mineral system (CM Dextrin > MP Dextrin > Dextrin TYM). Competition between the valuable and gangue mineral phases for uptake of MP Dextrin is responsible for its observed decrease in efficiency in mixed mineral flotation. All three polymers were found to be reasonably selective in their action, although at high dosages the polymers began to affect the flotation of the valuable minerals.

Jan 1, 2006

By G. C. Nowlan, A. Illis, H. J. Koehler

At its iron ore recovery plant at Copper Cliff, INCO produces about 17 million pounds per year of a pure, acid-soluble, dense nickel oxide from nickeliferous pyrrhotite. The process used is also applicable to a broad range of ammoniacal nickel-bearing streams. The product has been widely accepted by the chemical, ceramic and electronic industries.

Jan 1, 1970

By Gurinder Kaur

Selenium (Se) based materials find wide applications in rectifiers, solar cells, photographic exposure meters, data storage devices, xerography and anticancer agents. They are also used in the glass industry to eliminate bubbles and remove undesirable tints produced by iron. In addition, Se is highly reactive towards a wealth of chemicals that can be potentially exploited to convert Se into other functional materials such as CdSe, ZnSe, Ag2Se. Here, we report a review of structural investigations of Se based materials in glassy and nanostructured forms. Glasses having varying amounts of Se and Tellurium (Te) were doped with group IV and V elements such as antimony and tin. Structural changes accompanying the composition variation were characterized with x-ray photoelectron spectroscopy, differential scanning calorimetry and x-ray absorption near edge spectroscopy. At the same time Se-Te nanoalloys were synthesized in aqueous micellar phase using Na2SeO3/Na2TeO3 as the Se/Te source. Morphology change from nanoparticles to nanoribbons was investigated using Scanning and Transmission Electron Microscopy (SEM/TEM) techniques. Structural investigations were also done for well defined morphologies of Se based nano-biomaterials obtained in the presence of water soluble protein bovine serum albumin (BSA).

Aug 1, 2013

By T. R. Chari

The safe-level dilution of low-level radioactive wastes in large volumes of selected granular material is proposed as an alternative method of permanent waste disposal to current Canadian practice of concentration and encapsulation. Accepting the fact that a "background level" of radioactivity exists throughout the world, the authors feel that the concept of controlled dilution of radioactive wastes to a level in keeping with "background" is a plausible alternative to current thinking on the subject and is worthy of equal consideration.

Jan 1, 1979

By Jan Kvinge, Aina Opsal Bakke, Yanjun Li, Jan-Ove Løland, Svein Jørgensen

"Compound casting is a very attractive approach to reduce the weight of components for some specific applications while keep both the functional and the mechanical property requirements. In this work, Al-7Si-Mg alloy /copper compound castings were produced through a low pressure die casting process. To reduce the oxide present in the interface, flux coating of the copper pipes was tested. The interface layer formed between the two alloys was investigated using Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Vickers Micro-hardness was also measured across the interface. Results showed that the flux coating prevented the formation of the metallic bond between copper and aluminum. Instead, high concentrations of potassium, magnesium and fluoride, coinciding with formation of KMgF3 and MgF2, were detected in the interface. In the castings without surface treatment, a continuous metallurgical bond was achieved. In the bond layer, various Al-Cu intermetallic phases have been detected. In addition, formation of primary silicon particles in the reaction layer was observed in all castings. The mechanism for the formation of the intermetallic phases and the strength of the interface layer have been discussed.INTRODUCTION Recent development in the automotive industry has focused on producing lightweight components, which can reduce CO2 emission and increase the efficiency. Often, one material alone is not able to meet the requirements for a specific use. The need for lightweight bimetallic components has therefore increased. Aluminum-copper bimetallic components can be used in wires and bus bars where conductivity is an important factor (Lee, Bang, & Jung, 2005). Compared to Al-Cu alloys, Al-Cu bimetallic components can reduce both weight and cost without reducing electrical and thermal conductivity (Sheng, Yang, Xi, Lai, & Ye, 2011). A challenge is, however, that aluminum and copper have high affinity to each other, especially at elevated temperatures. This causes formation of brittle intermetallic phases with high electric resistance (Liu, Wang, Sui, Wang, & Wenjiang, 2016). In addition, both metals are subjected to oxide formation on the surface. Copper is especially exposed to oxidation at elevated temperatures (Pinnel, Tompkins, & Heath, 1979), while a thermodynamically stable oxide layer will spontaneously form on the aluminum surface (Papis, Loeffler, & Uggowitzer, 2009). Oxides are known to be passive substrates, which will reduce wettability and will thus prevent the formation of metallic bonding between aluminum and copper (Papis, Hallstedt, Löffler, & Uggowitzer, 2008)."

Jan 1, 2018

By R. D. Brown

"Taxation tends to be a depressing subject. Taxes are unfair, taxes are too high and, above all, taxes are too complicated.In a recent address to the Canadian Tax Foundation, the author discussed in a rather more lighthearted way the possible causes of the complexity of the present Canadian taxation system. In order to provide an element of relief in this series of articles on taxation matters, extracts from these remarks are quoted below :"

Jan 1, 1976

By Sang-Kyun Woo

The electric power conduit (EPC) in Korea has been constructed since 1978. Facing the challenge of safety and sustainability of the EPC, it is urgent to develop an inspection strategy and maintenance system for the structure based on the concept of life-cycle management. This paper introduces the newly developed mobile inspection and diagnostic system of the EPC. The novel aspect of this particular system is the integration of non-destructive mobile inspection techniques with BIM (Building Information Modeling) and LBS (Location-Based Service). BIM is an ideal tool and platform for developing an inspection and diagnostic system, and RFID (Radio Frequency Identification) is a useful tool to construct USN (Ubiquitous Sensor Network) for LBS. The goal of this research is to establish an EPC inspection and diagnostic system concept based on BIM and LBS using RFID. In this research, a BIM model of OPENTBM tunnel for EPC will be established to show the integration of 3D CAD with the inspection data. An EPC?s maintenance database, which includes the deterioration types of the structure, inspection records, and repair methods, was designed to interact with the BIM. The system will be implemented by the BIM with the related database, in which the construction geometry and all related information are stored. The proposed system was designed to utilize the inspection and diagnostic system under the USN environment using RFID in EPC directly.

Aug 1, 2013

By B. Fang

Electrochemical behavior of an X-80 pipeline steel, including frequency-sweep electrochemical-impedance spectroscopy (EIS), time-sweep EIS at a constant frequency and open-circuit potential (OCP) monitor, was investigated using four-point bending specimens subjected to a stress-corrosion cracking (SCC) test in a near-neutral pH environment, The capacitive loop became smaller with test duration, revealing an increase in the corrosion rate, The resistance obtained in the constant-frequency EIS test showed two regions, of which the region with a remarkable decrease in resistance transformed into a region of slow decrease, whereas the capacitance increased with test time indicating that iron dissolution was fast at first, and then a corrosion product or film formed and covered the surface, leading to the pitting formation.

Jan 1, 2005

By J. E. Dutrizac, Alba Sunyer

The factors affecting the precipitation of arsenic-free alunite (KAl3(SO4)2(OH)6) were investigated in a series of laboratory experiments. Although the amount of alunite precipitated increased with increasing retention time, temperature, solution pH and the concentrations of Al(SO4)1.5 or K2SO4, the composition of the products remained nearly constant. The preferred conditions identified for the precipitation of arsenic-free alunite were then used to assess the behaviour As(III) and As(V) during alunite precipitation at 98°C. Increasing additions of As(III), as NaAsO2 or As2O3, resulted in a slight increase in the amount of precipitate formed at pH 2.80. However, X-ray diffraction analysis showed all the precipitates to be alunite, and <0.2% As(III) was detected in the products. In contrast, increasing additions of As(V), as KH2AsO4 or As2O5, resulted in significant increases in the amount of precipitate formed at pH 2.80 or 3.00. Furthermore, the arsenate (AsO43-) contents of the precipitates increased up to 15%, and the sulphate contents decreased, as the As(V) concentration of the synthesis solution increased from 0 to 9 g/L. X-ray diffraction analysis of the products detected only alunite, but there was a progressive expansion of the alunite cell with increasing arsenate content. The implication is that arsenate substitutes for sulphate in the alunite structure. Preliminary observations on the environmental stability of the arsenate-bearing alunite using the TCLP protocol gave solubilities <0.4 mg/L from a precipitate containing 8.5% AsO4 and 7.8 mg/L from a product containing 19.5% AsO4. Thus, it appears that alunites containing less than -10% AsO4 would be an acceptable vehicle for the disposal of arsenic from hydrometallurgical processing solutions.

Jan 1, 2011

By Robert B. Parsons

"Effective January 1, 1990, mines in British Columbia are subject to a new provincial mining tax statute, the Mineral Tax Act. Under this Act, mines are subject to a two-tier tax system, with a minimum tax payable on ""net current proceeds"" and a higher tax paid on net income. For many mines, the present value of tax paid under the new rules should be comparable to the amount paid under the old rules. Earlier cash payments could pose difficulties, particularly for smaller mines, but existing producing mines could benefit in the short-term.IntroductionEffective January 1, 1990, British Columbia has replaced the provincial mining tax regime under the Mineral Resources Tax Act with a new system under the Mineral Tax Act. The new rules borrow some ideas from other provinces (New Brunswick&apos;s two-tier concept, and Saskatchewan&apos;s indexed costs) with a view to levying a tax that is fairer to both the producer and the province."

Jan 1, 1990

By F. Chiesa

Forty aluminium A356 castings were poured on a Low Pressure Permanent Mould industrial machine, 500x700mm in platen size. The 152mm wide casting comprised three steps, 25mm, 13mm, 6mm in thickness and a 2.5mm overflow which allowed to assess the thin wall capability of the process. The casting campaign, which produced 40 parts, allowed to test the influence of various production parameters including the time of application of the pressure in the crucible, artificial cooling of the mould and casting rate. The thermal history in the mould was recorded over the 40 cycles, which allowed to construct a reliable thermal model of the mould/casting assembly. The metallurgical quality of castings representative of the various conditions was assessed in the 25mm, 13mm and 6mm plates. This included measuring the level of microporosity, the dendrite fineness (DAS), along with the tensile properties in the T6 condition. The radiographic quality per ASTM E155 was also determined. Modelling filling and solidification allowed to verify the validity of the predictions based on available relationships relating microporosity, secondary dendrite arm spacing (DAS) and local tensile properties (Quality Index, Q) to the local thermal solidification parameters.

Jan 1, 2007