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By T. Hidayat, D. Shishin, V. Prostakova, M. Shevchenko

The chemical compositions of copper feed streams are becoming increasingly complex following the growing demand for metals and corresponding shortages of primary sources. The optimisation of process conditions requires an accurate description of phase equilibria and thermodynamics. Integrated experimental and thermodynamic modelling research program on the characterisation of the complex, multi-component, multi-phase gas-slag-matte-speiss-metal-solids Cu2O-PbO-ZnO-Al2O3- CaO-MgO-FeO-Fe2O3-SiO2-S-(As-Bi-Ni-Sb-Sn-Ag-Au) system is being carried out to support companies undertaking the pyrometallurgical primary production and recycling of copper. The experiments involve high temperature equilibration in controlled gas atmospheres, rapid quenching and direct measurement of equilibrium phase compositions with quantitative microanalytical techniques, including electron probe X- ray microanalysis and Laser Ablation ICP-MS. The thermodynamic modelling is undertaken using FactSage computer package with advanced thermodynamic solution models. The continuing development of research methodologies has resulted in significant advances in research outcomes. Implementation of the results of these fundamental studies involves an ongoing collaboration of researchers and industry technologists. An overview of recent progress in research, implementation and applications in industrial practice are given in the paper. INTRODUCTION Rapidly developing technologies increase the demand for various metals in number and volumes. Modern technological devices such as mobile phones, computers, other electronic devices, have dozens of metals—all those metals have to be a) produced and b) recycled. The fast transition in mobility from fossil energy delivered through combustion to renewable energy first stored in bakeries and delivered through electric engines introduce a significant change in the metal demand in terms of both type and volume of metals. Pyrometallurgy is playing a key role in supporting these changes in our industrialised society.

Jan 1, 2019

By Shuguang L, Jing S

Computer controlled truck dispatching systems is a newly-developed technical system in surface mines with shovel-truck technology. The real time dispatching criteria, as the core of optimal truck dispatching software, are analysed and a new criterion, complex dispatching criterion, is put forward. Dispatching criteria previously proposed include: 1. `Earliest Loading' (EL) - to assign a truck to the shovel at which the truck can be loaded earliest. 2. `Max Truck' (MT) - to assign a truck to the shovel at which the truck will have the shortest waiting time. 3. `Max Shovel' (MS) - to assign a truck to the shovel which has been waiting for the longest time. 4. `Minimum Saturation Degree' (MSD) - to assign a truck to the shovel at the branch where the truck flow saturation degree is minimum. 5. `Minimum Saturation Degree with Truck Cycle time consideration' (MSDTC) - as the MSD principle, with the truck travel cycle also considered. 6. `Fixed Dispatching' (FIX) - to assign trucks to fixed shovels. A system simulation model has been set up for truck dispatching system analysis. A few surface coal mines have been selected for case studies. Equipment waiting times and shift production of the system are obtained as the main outputs of the model. Simulation results show that each dispatching criterion has its own applicable range, no one can absolutely dominate the others. For example, when under-trucked, EL and MT criterion can obtain higher production than the MS criterion; when over-trucked, it is vice versa; while for MSD criteria, better results can be obtained no matter how the truck numbers fluctuate. From the view point of shovel output balance, large fluctuations occur for EL and MT criteria, while a good balance can be obtained for other criteria. In the light of dynamic change of mining system conditions, a single dispatching criterion is not necessarily reasonable. A complex dispatching criterion has been put forward to seek the complex optimum effect. Taking the advantage of each dispatching criteria, the dispatching result of a complex dispatching criterion dominates over individual dispatching criterion and a comprehensive optimum effect can be reached.

Jan 1, 1995

By Renzo D. Verastegui, Michael Law, Sitotaw Y. Fantaye, Alfredas Daugiala

"When completed, 520 Park Avenue will amend the Manhattan skyline and be one of the most prestigious high-rise towers in New York City. The 52-story condominium building is located on a 60 ft by 100 ft lot (18.3 m by 30.5 m) on East 60th Street between Park Avenue and Madison Avenue. The geographically complex site is bounded by two fragile five-story masonry buildings on the east and west, a mid-rise building on the north, and a New York City Transit (NYCT) subway tunnel on the south. To add to this complexity, the ambitious development required an excavation between 70 and 80 ft (21.3 and 24.4 m) deep, mostly below groundwater level in highly-permeable rock, to accommodate four levels of cellars. The new building also cantilevers 24 ft (7.3 m) over a five-story historic building on the east. The limited footprint of the building coupled with large compressive and tensile axial loads, considerable base shear and over-turning moments, and the required deep excavation, presented unique foundation challenges. This article describes how the challenges were solved with an innovative combination of permanent secant pile walls and drilled shafts.Site GeologyThe 1865 Viele Map provides the site topographic conditions prior to development in the area, and indicates that the site was at the eastern edge of a historic marshland, which was approximately west of Park Avenue and north of 58th Street. A historic stream, which ran alongside the eastern edge of the site, was part of a larger stream network that traversed the surrounding area. This stream network is also visible in the 1865 Viele map. In addition, the bedrock beneath the site lies in a highly weathered zone due to a couple of ancient faulted zones that transect the site. These indicate that a zone of highly weathered rock is expected."

Jan 1, 2017

By Shadia J. Ikhmayies

"Cadmium sulfide thin films were prepared on glass substrates by the spray pyrolysis technique at a substrate temperature of 490°C. Some of the films were etched by HC1 in distilled water, others were heat treated in nitrogen atmosphere, and another set of films was first etched by HC1 and then annealed. Room temperature impedance spectroscopy measurements on the films were performed using coplanar geometry in the dark and in room light in the frequency range 20 Hz to 1 MHz. The experimental data were represented by complex plane diagrams and showed one well-defined semicircle in the high frequency region. Hence the equivalent circuit that models the CdS: In thin films was found to be a single RC circuit, which indicates the bulk conduction through the grains. The influence of treatments on the electrical properties was investigated.IntroductionCadmium sulfide (CdS) is a brilliant II—VI semiconductor material with a direct band gap of 2.42 eV at room temperature. It has many outstanding physical and chemical properties, which have promising applications in multiple technical fields including photochemical catalysis, gas sensor, detectors for laser and infrared, solar cells, nonlinear optical materials, various luminescence devices, optoelectronic devices and so on [1]. There are different methods to prepare undoped and doped CdS films, such as rf sputtering [2] chemical bath deposition (CBD) [3], pulsed laser deposition (PLD) [4], and spray pyrolysis (SP) [5-11]. Of these methods, spray pyrolysis represents the less expensive option, and can produce large area high-quality low cost thin films [12]."

Jan 1, 2012

By Zhongxue Li, Shuang Gao, Zhixin Zhen, Yiqing Zhao, Xuan Qin

If not well-managed, a mine-tailings facility may become a major source of risks, endangering the community and environment, and damaging the reputation of the minerals industry regarding sustainability. Identifying, characterizing, and mitigating the hazards and risks associated with tailings facilities have been critical to the maintenance of community-safe and environmentally sound mine-tailings facilities. Herein, a complex network model for characterizing the hazards and risks associated with the lifecycle of tailings facilities is presented. In this approach, the hazards are modeled as vertices of the complex network, and the interactions among the hazards are modeled as edges of the complex network. The complex network for modeling the hazard and risk spreading of mine-tailings impoundments is analyzed and characterized by using network metrics such as the network density, geometrical characteristics, characteristic path length, network efficiency, and clustering coefficient. The degree distribution of the network obeys a power-law distribution, indicating that the network for characterizing the risk spreading associated with a tailings facility is scale-free. According to the results of calculations and existing research results, the network is ultrasmall-world. By analyzing the change of the global network efficiency under four kinds of different methods to remove network nodes and edges, network nodes with higher between centrality (BC) are identified as critical. The removal of those critical nodes helps mitigate risks associated with a tailings facility and reveals the vulnerabilities to BC attacks.

Jan 1, 2017

By H. O. Ghaffari

A complex network approach on a rough fracture is developed. In this manner, some hidden metric spaces (similarity measurements) between apertures profiles are set up and a general evolutionary network in two directions (in parallel and perpendicular to the shear direction) is constructed. Also, an algorithm (COmplex Networks on Apertures: CONA) is proposed in which evolving of a network is accomplished using preferential detachments and attachments of edges (based on a competition and game manner) while the number of nodes is fixed. Also, evolving of clustering coefficients and number of edges display similar patterns as well as are appeared in shear stress, hydraulic conductivity and dilation changes, which can be engaged to estimate shear strength distribution of asperities.

May 1, 2009

By J. A. Sweet, T. BACHMANN, G. E. Sandoval, T. M. Hauyon, F. A. Contreras

In many respects a porphyry copper ore concentrator plant can be considered as a simple system. Chalcopyrite typically liberates well at relatively coarse sizes, and even low grade ores are amenable to upgrading 20 to 30 times to produce concentrate grades in excess of 25 % in very simple Rougher- Regrind-Cleaner+Scavenger flotation circuits. The flotation response of chalcopyrite has been well characterised in many fundamental and applied research studies and the conditions necessary to depress pyrite and other floating gangue species are well understood. But what happens to the particle surfaces when you have a 50 km pipeline between the grinding circuit and the flotation plant? How does the seasonal variation in water quality affect your ability to control pulp chemistry? What impact does the relative concentration of the different sulphide species have on their separability? Why do two plants that receive nominally the same ore produce consistently different results? And most importantly, what do you need to do to improve the performance of both plants? To answer these and other questions, a focussed sampling and analysis programme was carried out at the Las Tórtolas flotation plants in 2018 and 2019. The work included full down-the-bank sampling, hot floats, the use of radioactive tracers for determining residence time distribution profiles, gas dispersion measurements, detailed mineralogy by size across the circuits and multiple regrind surveys. This comprehensive study was augmented by analysis of historical mineralogy, geometallurgy and operating data using modern data science techniques, and has provided the foundation for current and future optimisation initiatives. Some of the findings and their implementation will be presented in this paper. Keywords: Circuit optimization, Residence time, Gas dispersion, Pulp chemistry

Jan 1, 2020

By Y. Iguchi, T. Narushima, T. Shiozawa, M. Maruyama, R. Arashi

"In situ observation system for thermal oxidation using Raman spectroscopy' was constructed, and oxide films formed on liquid pure Al and Al-Mg alloys (Mg contents = 1 and 4 mass%) were analyzed at room temperature to 1273 K in dry oxygen. In situ Raman spectra of the surface of a liquid Al-:-4mass%Mg indicated the formation of MgO • AlP3 (spinel) as oxidation products, while a -AlP3 and MgO • Alz03 (spinel) were observed on a liquid Al-1mass%Mg alloy. It was suggested that the formation of MgO film affected oxidation behavior of these alloys.IntroductionLiquid aluminum alloys are cast to ingots mainly by the continuous casting process. It is well-.known that surface cracks could be caused by oxide films formed on the surface of melt during continuous casting and defects due to the film. With regard to oxidation behavior of liquid aluminum alloys, many investigations l -s have been carried out from the view point of formation of ceramic metal composites(CMC) which are expected as cutting tools and structural materials 1.2. It is very important for reasonable continuous casting and CMC formation processes to elucidate oxidation behavior of melts.Oxidation behavior of materials generally depends on compositions and properties of oxide films formed on the surface. If in situ observations of oxide films are available during oxidation, evaluation of oxide films and interpretation of oxidation mechanism could be expected. Laser Raman spectroscopy is one of the most appropriate techniques for in situ observation of oxide films under various atmosphere at high temperatures. The authors have discussed the effects of atmospheres and sample compositions on oxide film formation mechanism on Fe-Si alloy6 and SiC-B4C composite7 on basis of an in situ observation by Raman spectroscopy. In spite of many previous studies, systematic and clear explanations have never been gotten on oxidation behavior of liquid aluminum alloys. And no in situ observation has been made except for transmission electron microscopy(TEM) and X-ray diffraction(XRD)."

Jan 1, 1996

By Jamie D. McEwan

To cater for the future introduction of 12 car trains, London Blackfriars railway station is being extended from the north end to span across the River Thames. Following the demolition of existing buildings, a number of challenges had to be overcome including working adjacent to a live railway line, above live London Underground tracks and working in small restricted spaces. Trains entering and exiting two lines of track at the bridge's north end of track meant that access was difficult due to the location and proximity to existing infrastructure. The site was very much constrained and congested and there were also a series of works in place to maintain passenger flows so as not to inconvenience the travelling public. The site had been developed many times in the past resulting in a number of obstructions that would require removal during the piling work including old brickwork, reinforced concrete, redundant railway sleepers and track and existing concrete and timber piles. A number of solutions had to be devised to overcome these obstructions. Piling works were undertaken during the day and at night to meet programme.

Jan 1, 2011

By Ata Akcil, Z. B. Karshigina, Ye. G. Bochevskaya, Z. S. Abisheva

"Phosphorus slag is the most heavy-tonnage waste of yellow phosphorus production, which is stored in the dump fields for many years creating ecological problems in the regions. Despite of the actions taken to utilize the slags, most of them remain in the slag disposal area. One of the relevant and priority directions is rare-earth metals production (REMs), presence of which in the phosphorus slags allows considering the latter as an acceptable raw material source. Phosphorus slags contain about 30–40 wt% of silicon dioxide, therefore they can serve as a source of production of precipitated silicon dioxide highly required in different industries.The purpose of this work is the most complete REMs recovery in the solution while leaching and subsequent processing of siliceous cake. The work shows results of researches on establishment of the chemical and phase compositions of phosphorus slags, determination of the forms of presence therein of REMs compounds, processes of phosphorus slag leaching by nitric acid and processing of produced siliceous cake by NaOH solution.Based on the data of the instrumental and chemical methods of phosphorus slag analysis, it was established that it consists of pseudowollastonite a-CaSiO3 for 90–92%. It was found out that REMs are present in it in the form of carbonate apatite Ca10(PO4)6CO3 or rare earth apatite, and La2S3 compound inclusions.Optimum parameters of phosphorus slag leaching process were selected: HNO3 concentration 7- 7.5 mol/L; L/S ratio = 2.6–3 mL/g; temperature – 50–80o?; duration – 1 h; pulp stirring – 500 rpm. Recovery of SREMs, CaO, Al2O3 and Fe2O3 into the solution were achieved at 98.0, 99.1, 99.0 and 18.8%, respectively. Presence of 10 elements of the rare earths group in the phosphorus slag was established. It was found out that recovery of almost all REMs is within ~92–99%, except for Sc and Lu – ~39% and ~28%, respectively.For the purpose of optimization of siliceous cake leaching by NaOH solution, influence of some physical and chemical parameters was studied: N?O? concentration, L/S ratio, temperature, and duration. Results of the experimental data will serve as a basis for development of the technology of complex processing of the technological waste of phosphorus industry with production of REMs concentrate and precipitated silicon dioxide."

Jan 1, 2016

By Lawrence M. Gochioco

The interpretation of coal seismic data requires a certain precision and accuracy to make the results more reliable. The signature of the seismic wavelet provides a host of valuable geologic information. Subtle features and anomalies, not easily observed in conventional black and white seismic sections, are enhanced through color attribute displays in terms of frequency, amplitude and phase. Coal seam anomalies like sandstone washouts produce a distinct pattern in frequency and amplitude displays due to the change in the net acoustic impedance contrast. Faults produce frequency and amplitude variations due to interference within the Fresnel zone that straddles the fault. The magnitude of displacement is estimated by studying the effects of faults on reflection amplitudes and frequency from computer-generated models.

Jan 1, 1989

By E. V. Mezentseva, S. M. Okunev

"In the article there is set forth a development experience of JSC LEBEDINSKY GOK Beneficiation Plant concerning the plan of increase in the production volumes of the iron ore concentrate with Fe content more than 69.5%. There are considered the issues regarding implementation of the updated process scheme of the concentrate beneficiation using fine screening operation, its industrial tests have shown an exploitability of this development direction. There are described the issues relating to the ceramic filters for dehydration of the additionally-beneficiated concentrate, there are given the production and process figures achieved during the exploitation. The methods of the research. In the paper there have been used the following scientific research methods: the methods of system analysis, mathematical statistics, classification, comparison, modelling, observance, experiment. INTRODUCTION JSC LEBEDINSKY GOK is the largest leading enterprise for iron ore beneficiation and the unique RF producer of the merchant hot briquetted sponge iron (HBI) highly demanded by the consumers. Raw materials for hot briquetted iron production are fluxed pellets produced from iron ore concentrate with Fe content more than 69.5% (additionally-beneficiated concentrate). Strategic program of the plant’s development foresees expansion of production of the highly demanded products that imposes a necessity of expending capacity of the enterprise and implementation in production of modern processes and equipment having low resource intensity and ensuring in addition a high efficiency. Construction of the third stage of the HBI Plant became one of directions for the strategic development of JSC LEBEDINSKY GOK implemented in 2017 that caused a demand in the production volumes and filtration of the iron ore concentrate with Fe content more than 69.5%. Purpose of the work – to develop and to provide a rationalization for efficiency of the production process and filtration of the iron ore concentrate with Fe content more than 69.5% ensuring increase of production volumes and its prime cost."

Jan 1, 2018

By Schmincke H-U

The Pleistocene basanite-tephrite Rothenberg cone complex was built by an alter- nation of strombolian and phreatomagmatic phases of explosive eruption. Two main centres, on a one km long NNE-trending fissure, were active during its construction. The strombolian deposits from three discrete facies corresponding to the crater-fill and inner wall and outer wall environments on the cone. The outer wall facies consists of an alternation of 1. 'normal' coarse-grained, relatively well- sorted lapilli and bomb beds, and 2. finer-grained poorly-sorted lapilli beds. Evidence suggests that the former was pro- duced by open-vent lava fountaining, with balanced magma supply and discharge rates, and the latter are the products of eruptions during partial blockage of the vent, by collapse of wall-rock, and formation of a degassed crust on the magma. The resulting explosions there- fore ejected a mixture of fresh actively ves- iculating magma, older partially degassed lava and material recycled from the wall of the cones. The phreatomagmatic deposits are an alternation of moderately-sorted fall beds and thinner ash-rich pyroclastic surge and rain-flushed units. The clast populations are much more diverse than strombolian ones, including abundant wall rock fragments from 0-100 m depth. The juvenile (magmatic) particles range from highly vesicular scoria to dense 'bread-crusted' clasts, and contain abundant small wall rock inclusions. The phreatomagmatic phases are products of explosive interaction of small batches of magma with shallow groundwater. Vesiculation of this magma played a small but significant role throughout the fragmentation.

Jan 1, 1987

By Shila Jafari, Mari Lundström, Aleksei Kritskii, Pia Sinisalo

A typical process adopted at nickel plant is the processing of nickel-copper mattes and converter mattes using the following technology: pressure oxidative leaching (POX), solvent extraction (SX), electrowinning (EW), cobalt recovery, and solutions purification. As a result of multi-stage atmospheric and autoclave process leaching, copper-nickel separation is achieved. Cobalt and nickel are further separated by SX. Copper in the process can be removed as copper cake (Cu-cake), which is a by-product with high content of valuable metals. In the current paper, a method combining atmospheric and pressure leaching of Cu-cake in sulfuric-acid media is discussed. Suggested method allows to obtain high copper extraction (>98%), with leach residue containing precious metals and PGMs. Sulfuric acid media was chosen to make the suggested technology adaptable for the primary POX-SX-EW circuit. The initial Cu-cake was analysed and a range of process parameters (t = 25–190°C; PO2 = 0–7 bar) investigated to achieve the optimal conditions for leaching process at the ambient as well as at increased pressure. As a result, an initial process block diagram for the treatment of Cu-cake with high copper leaching efficiency and low metal losses is provided. INTRODUCTION The conventional technology for nickel sulphide ore processing includes the following main stages: froth flotation, matte smelting and converting. The subsequent processing of nickel converter matte is possible using fundamentally different approaches - hydrometallurgical (Llanos, Queneau & Rickard, 1974; Rademan, Lorenzen & Van Deventer, 1999; Kshumaneva, Kasikov, Neradovskii & Belyaevskii, 2009; Dutrizac & Chen, 2013) and pyrometallurgical (Tsymbulov, Knyazev, Tsemekman & Golov, 2007). Hydrometallurgical approach in comparison with pyro-process has several advantages, such as reduced environmental load, reduced PGM losses, increased copper and nickel extraction. Typically, hydrometallurgical technologies include leaching, solvent extraction as well as nickel and cobalt recovery in metallic form by electrowinning or hydrogen reduction or as valuable metal salts via crystallization process (Crundwell, Moats, Ramachandran, Robinson & Davenport, 2011).

Jan 1, 2019

By M. Leroux, C. J. Martin, S. R. Rao, J. A. Finch

"The effect of nitrogen on the flotation separation of sulphides from complex ores from Brunswick Mining and Smelting (New Brunswick) and Mattabi Mines (Ontario) was investigated. The most significant finding was enhanced pyrite floatability after as little as 3 minutes nitrogen conditioning. This was used in a novel sphalerite/pyrite separation process developed on the Brunswick ore. After aeration and Cu/Pb bulk flotation in air using xanthate the slurry was nitrogen conditioned, xanthate added and the pyrite floated in nitrogen. As an example up to 70% pyrite recovery with about 20% sphalerite recovery was achieved. Sphalerite was recovered from the pyrite tailings and the pyrite concentrate by copper-activation, raising the pH to 10 and floating in air. About 65-70% recovery at 35-40% Zn grade was achieved compared to 25% Zn grade by the conventional route. The process offers a promising alternative to current practice which seeks to depress pyrite at all stages. A possible mechanism of the effect of nitrogen is presented. INTRODUCTIONUse of gases other than air in froth flotation has been reported from time to time. [Podobnik and Shirley, 1982; Lin and Metzer, 1975]. Of all the gases, nitrogen would appear to hold the greatest practical promise because of its easy availability and chemical inertness. It is used in froth flotation in chalcopyrite-molybdenite separation [Redfearn, 1983]. The use of nitrogen in polysulphide chalcopyrite. this case is mainly to reduce the oxidation of a compound (Nokes reagent) used as a depressant for There is no reported use of nitrogen in the flotation of other sulphide minerals."

Jan 1, 1988

By Miroslav Cervenka

The Coal, characterized by coal quality parameters as for example, ash content (Ad), moisture (Wrt), heat content (Qr1), sulphur content (Sd) and other parameters is still in many countries the basic source of energy. Energy is life, especially in modern society, where the demand for ecologically clean energy is very high; and therefore, there is great importance in effective coal utilization Direct utilization - burning of coal for energy generation, is still one of the most effective methods. In most cases, it is one of the cheapest energy transformation methods in spite of the fact that this energy transformation is connected with the deterioration of our surroundings. Deterioration can be substantially reduced if the burning of coal at power stations, heat power stations and other coal consumers is optimized. That means the burning is done in steam boilers, the technical state of which is very good; the coal has minimimum .variations with respect to the projected values; and the burning process is controlled and checked not only from a regulation point-of-view but also from an ecological point-of-view. The instrumentation capable of measuring the characteristic coal quality parameters in real time exists and it forms the basic assumption for the work our research team has made. The proper application of this instrumentation is able to provide information for burning process optimalization. It is the main topic of this paper, which is the compilation of the information on our work -made during the last five years. The whole information is based on practical experience and applied systems in Czechoslovakia in the mines and power engineering industry. See [Cervenka, 1989]

Jan 1, 1992

By E. V. Zelinskaya, A. E. Burdonov

"In the raw aluminum production processon electrolyzers with self-baking anodes, during technological operations, flow-regulated treatment and adjustment of the electrolyte chemical composition produced by diesel and floor-rail technology, alumina and fluoride salts are spilled through the ventilation grilles of the electrolysis body aeration channels, leakage in the equipment, machinery and motorized machinery construction elements. As a result of this, a part of the bus station and the level of ± 0 (the basement room with supporting curbstones and columns, on which electrolyzers are installed) are covered with technological raw material. This leads to an increase in the conductor (bus) resistance, contact connections deterioration, cell insulation failure and raw materials loss. For example, at the enterprise ""Rusal-Bratsk"", as a result of the activity, up to 420 tons per month of alumina-containing wastes that are unfit for use in the electrolysis process are formed due to the alumina substantial contamination with salts of iron and silicon, which significantly reduces the technical and economic parameters of the electrolysis process. The main scientific problem is the processing (cleaning) of alumina-containing waste having a complex mineralogical composition of the material, its contrast and structure, from oxides of iron and silicon, using ""dry"" separation methods. In the performing the work process, qualitative indicators of the influence of external factors (air humidity, precipitation, sunlight, temperature difference) on the physicochemical processes components interaction during the raw materials storage are established. On the basis of laboratory tests, it is established that alumina-containing raw materials can be separated and photometric and gravitational separation methods used. A mathematical model of the motion of particles of primary and prepared alumina-containing raw materials in a cascade-gravity classifier was developed. The criteria and factors characterizing the alumina-containing material, as well as influencing and determining the maximum material enrichment, are established."

Jan 1, 2018

By F. Sekula

Tetrahedrite and siderite are two main valuable minerals present in the silver Mária Bana deposit. The tetrahedrite concentrate prepared from it by flotation has certain specific properties from the metallurgical point of view. Siderite is concentrated in the flotation tailings. The paper presents results of the laboratory and pilot-plant testing of the combined hydrometallurgical and pyrometallurgical methods proposed for treatment of the tetrahedrite concentrate and siderite waste. The testing conditions were based on thermodynamic analysis of the reactions that proceed in the process. The proposed technology makes it possible to separate copper from sulphur, mercury and iron in a straightforward way. Copper, after its refining, can be subsequently treated in the finishing operations. At the same time it is a valuable source of precious and noble metals. The siderite-containing flotation tailings can be converted to iron of the technical purity and slag. The proposed method is a good starting point for the development of the closed-cycle technology.

Jan 1, 2006

By V. A. Chanturiya

In Pt- and Au-keeping complex ores processing, about 10% ~ 15% of noble metals are lost with true tailings that are due to low floatability of Pt- and Au-keeping minerals by the conventional collectors. With the aim to achieve the effective recovery of noble metals at flotation of Pt-Cu-Ni and Au-keeping ores organic complex reagents keeping electron-donating atoms of nitrogen, oxygen, sulfur or phosphorus may be offered as selective collectors for the indicated minerals. These rea-gents tend to form complex compounds with PGM. Besides this, Cu-Ni-Pt and complex Pt and Au carbonated mica ores are characterized by finely disseminated (up to nanometer size) mineral forms of Pt in multivalent states. In this connection, the use of a combination of the strong ionic collectors with nonionic reactants that are capable to derivate complex compounds with multivalent PGM seems to be expedient for this type of ores. In the research new complex reactants were tested such as cyclic alkylene-trithiocarbonates, oxyalkyl butylxanthogen acid ethers, a combination of the collectors ? mercaptobenzothiazole (MBT) and dialkyldithiophosphates (DTP). Sorption and flotation tests were made with monomine-ralic samples of chalcopyrite, pentlandite, pyrrhotite, pyrite, and Pt-Cu-Ni sulfide ore samples. Sorption properties were examined by the extractive UV spectrophotometric method and potentiometric measurements. To indicate a structure of modified xanthate solutions the method of a thin-layer chromatography (TLC) was applied. The chromatographic behavior of the basic components of modified xanthate solution ? ButX, cyclic propylene-trithiocarbonate (PTTC), diethyl-dithiocarbamate (DEDC) and the product of its modification ? oxypropyl-S-ether of dithiocarbamatic acid was studied on plates ?Silufol UV ? 254?. The composition of organic solvents and its ratio in a mobile phase was deter-mined for simultaneous chromatography of the main components of a reaction mixture. It was found that operating selectivity of MBT, DTP and cyclic alkylene-trithiocarbonates incorporated in modified xanthate in relation to Pt-Cu-Ni and Au-containing sulfide minerals might be explained by an electoral sorption of this nonionic collector on a surface of the minerals studied. It was demonstrated that the application new reagent modes with the use of a combination of designed complex reactants helped to increase the extraction index of Pt- and Au-keeping minerals from complicated ores.

Jan 1, 2014

By R. J. Lipp, I. Iwasaki, R. H. Heerema

The presence of calcium ion in iron ore pulps that are upgraded by selective desliming can result in indiscriminate flocculation of both iron oxide and siliceous gangue slimes. In order to overcome this adverse effect, deflocculation by three complexing agents, namely ethylenediaminetetzaacetate (EDTA), sodium tripolyphosphate (STPP), and sodium hexametaphosphate (SHMP), was investigated. The precipitates and complexes of these agents with calcium ion were characterized by potentiometric and conductometric titrations, and the surface properties of quartz and goethite were studied in the presence of calcium ion and of the complexing agents by means of streaming potential measurements and flotation tests. The results were then correlated with selective flocculation tests on an artificial mixture of quartz and goethite. EDTA markedly improved the selectivity of flocculation when added in near stoichiometric amounts, whereas STPP was less effective and SHMP was totally ineffective due to strong, indiscriminate dispersion. Remanent calcium polyphosphates on the goethite surface interfered with the adsorption of starch flocculant.

Jan 1, 1983