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By Alessandro Navarra, Joël P. T. Kapusta

"The converting cost modeling software introduced by Ng et al. in 2005 [1] has been extended to consider the reprocessing of reverts and copper scrap. The original model evaluated the operational costs of a Peirce-Smith converter; algebraic relationships had been implemented with arrays (to represent matrices, vectors and scalar ratios). The new software brings flexibility to the underlying thermochemical balances, by using linked-lists instead of arrays. It is now possible to consider the blending of several feeds, including reverts and scrap.The software computes the length of the converting cycle from the Fe and S content of the charge together with the blowing rate; the times required for other operations (charging, skimming and idle time) are also accounted for. The costs of consumables such as flux, fuel, oxygen or compressed air are all evaluated. Downtime, labor, and materials for converter lining repairs are also considered. The software is easily extended to examine the costs of alternative operating strategies or injection technologies such as sonic single pipe injection and sonic shrouded injection. The potential cost benefits of alternative operating procedures and technologies are discussed through example calculations."

Jan 1, 2009

By Chunhua Liao, Chao Peng, Guangsheng Huo

To get the separation of tungsten and molybdenum, we adjusted the pH of the solution to 7, at which tungstate (WO4 2-) will be polymerized into HW6O21 5-, while molybdate will still exist in the form of MoO4 2-. Two strongly basic anion exchange resins (D201, D213) were experimented for the separation of tungsten and molybdenum. The results of condition experiments indicate that D213 resin performs better in the treatment of lower concentration solution A (WO3 10g/L, Mo 4.12g/L) with a separation factor as high as 10.64. While D201 resin is more suitable for the high concentration solution B (WO3 70g/L, Mo 28.97g/L) with a separation factor of 6.9. The results of column testing performed on D213 resin show that the solution after loading process with a mass ratio of Mo/WO3 = 50 and the desorption solution with a mass ratio of WO3/Mo = 27 can be obtained

Jan 1, 2014

By Huimin Lu, Neale R. Neelameggham, Guangzhi Wu

In China’s Inner Mongolia Tuquan County, 1.4 billion tons of reserves of serpentine deposits were found. Because serpentine belongs to magnesium silicate, there is no good reducing agent to reduce magnesium. In the local there is also a large reserves of high-aluminum bituminous coal for thermal power, power plants each year produce a large number of high-aluminum fly ash. The aluminum-silicon alloys obtained from this high-aluminum fly ash as the raw material by carbothermal reduction method can reduce the magnesium from the serpentine. In this paper, first, the feasibility of producing aluminum-silicon alloys by carbothermal reduction of high-alumina fly ash was studied, the hypereutectic aluminum-silicon alloys were obtained; and then the investigation on aluminum-silicon alloy as a reducing agent to reduce of metal magnesium from serpentine was carried out. According to the previous investigation, the optimized technical process for the extraction of metal magnesium from serpentine was proposed.

Mar 1, 2018

By M. Oliazadeh

Spodumene [LiAl(Si2O6)] is the most common and desirable economic lithium-bearing mineral due to its high lithium content. In Canada, there are several spodumene deposits at the development stage that have the potential to help narrow the forecast lithium supply gap stemming from the widespread acceptance and increasing use of electric vehicles. Spodumene processing can be conducted using Dense Media Separation (DMS), flotation or combination of both. If spodumene liberation is sufficient at coarse particle sizes, DMS can be used for primary lithium concentrate production and silicate gangue minerals rejection. If liberation is not sufficient, flotation is then the main processing route for spodumene concentration. Even in cases where DMS is a viable beneficiation option, flotation may still be required to process the DMS middlings and/or the undersize fraction which is outside the particle size range for DMS. Considering flotation as a technique for spodumene beneficiation, there are several alternatives including the use of mechanical flotation cells, column flotation cells, coarse particle flotation cells, and/or Staged Flotation Reactors (SFR), either alone or in combination. Ore sorting can be incorporated at the start of the spodumene flowsheet to remove gangue minerals, particularly amphibole and pyroxene in the early stages. The main objective of flowsheet development for hard rock lithium deposits is to evaluate the ability of these options to produce a spodumene concentrate with a concentrate grade above 6% Li2O, lithium recovery of above 80%, and with the minimum operating and capital cost. This paper aims to describe the various processing options available for the beneficiation of spodumene from hard rock deposits and compare the associated operating and capital costs for each.

By R. A. Spitz, R. Leiby, M. Bricker

Electrochemistry plays a significant role in minimizing wastes at East Penn's secondary lead smelter. East Penn has been recovering spent battery acid for reuse in new batteries since 1992. East Penn also produces a fertilizer feedstock from sulfur dioxide in the smelter stack gases. The success of these processes is, in large part, due to the installation of electrochemical cells. The cells in the acid recovery plant allow the waste from this process to be concentrated into less that 10% of the original spent acid. The cells in the fertilizer plant treat the solution to remove dissolved metals prior to sale to fertilizer manufacturers.

Jan 1, 2000

By René Bustamante

The subject of this paper is a comparative evaluation of different copper smelting gas cooling techniques, using "productivity and quality" criteria. The first section presents a brief description of the operation of the radiant and the evaporative cooling systems, focusing on the differences between each other, in particular regarding. a) mass and energy balances; b) gas flow, temperature and composition; c) dust concentration and recovery. This section includes a brief discussion of the "client-server chain", i.e. the links between the cooling equipment and the down-and up-stream operations. More in particular, the up-stream server relationship impacts on the operating stability of the furnace, and in turn on furnace down-time and Cu production losses; and the down-stream client relationship affects the operation of the electrostatic precipitators, in terms of workload and cost of handling larger quantities of dust of a given dust size The second section deals with the development of indexes to measure and compare value added through the "utilization, productivity and quality" that can be expected of both cooling methods at the physical and economic levels, and the impact on the overall smelter productivity and the final cost composition of copper. The final section presents the results and includes a discussion of the comparative advantages and disadvantages of both cooling systems.

Jan 1, 1999

By Yuzhe Zhang, Matthew Andriese, Jiann-Yang Hwang, Guanghui Li, Zhiwei Peng, Tao Jiang

The microwave power absorption characteristics of iron oxides, including Fe2O3, Fe3O4 and Fe0.925O, have been studied by determining dielectric loss and magnetic loss distributions in 0.05-m-thick oxide slabs irradiated with 1.2-kW, 2.45-GHz microwaves. The results reveal that the dielectric loss is the main factor contributing to microwave absorption in Fe2O3 and Fe0.925O, while the magnetic loss dominates the power absorption in Fe3O4 below its Curie point. Uneven power distributions are observed in the slabs and this phenomenon becomes even worse at high temperatures at which the permittivity increases significantly. Quantification of power absorption in the oxides is of great importance for efficient and uniform microwave heating

Jan 1, 2015

By M. Potesser

In the primary and secondary copper industry the anode furnace is the most important process step in the refining procedure to reach an enhancement in value and quality of the copper by a selective oxidation and reduction. By combining the advantages of the conventional tilting hearth anode furnace and the benefits of the drum type anode furnace a new aggregate was developed and patented. The cross-section of the furnace is elliptical and the whole unit is tiltable. During the melting period, the contact surface between the burners and the bath or the scarp is enlarged - an increased energy input is the consequence. For the refining period the furnace is rotated, whereby a high bath level is guaranteed. Due to the longer residence time of the gas in the copper melt, not only the gas consumption is reduced but also the efficiency/quality of the refining process is improved. This investigation shows a metallurgical comparison between the new anode furnace concept with the elliptical profile/cross section and the conventional, tiltable hearth anode furnace as well as the drum type anode furnace. The CFD modeling of the currents in these different furnaces delivered helpful data to compare the geometry of the different furnaces. The investigation covered the refining of blister copper from primary metallurgy, from secondary metallurgy as well as from a mixture of both copper melts. The paper underlines the possibilities for a reduction of the tap-to-tap time and for an increase in production capacity, which can be achieved by applying the new furnace concept in comparison to the conventional furnaces.

Jan 1, 2006

By Christopher Gammons

In developing countries throughout the world, gold ores are being processed by mercury amal-gamation, a technique long banned in the U.S. - unless a retort operation is used for mercury recovery - due to mercury toxicity and its effects on the environment. Amalgamation is a simple process that involves contacting a ground, slurried concentrate or ore with mercury in a slightly agitated vessel, usually for several hours, The amalgamated mercury is separated by gravity and then filtered through a fine cloth to collect the gold amalgam as a sponge, which is then fired to remove the final remnants of mercury and produce high quality gold. However, in Peru and other developing countries in South America and throughout the world, tailings are simply discarded into uncontrolled drainages and ponds and the sponge is fired in the open air. Clearly, in this case, environmental friendly and, to make matters worse, is typically conducted by family members of all ages without proper protection. Furthermore, the technique is inefficient, yielding approximately 50% gold recovery. For the past two years, faculty members from Montana Tech in Butte, MT, USA and the Universidad Nactonal del Altiplano in Puno, Peru have teamed to study the La Rinconada Mine Complex located in southern Peru approximately 100 kilometers north of Lake Titicaca and 25 kilometers west of Bolivia. The mining complex is over 5,000 meters above sea level and exists at the foot of a receding glacier in the Andes Mountains. A suite of soil and water samples collected in 2001 documented extensive Hg contamination in the Rinconada area [1]. The present paper summa¬rizes a follow-up investigation in July-2002, in which water samples were collected at numerous locations along the 200 km length of the Rio Ramis, from the Rinconada mine com¬plex to Lake Titicaca, In addition, we report new results of Hg analyses of fish from Lake Titi¬caca, The results of this study have relevance to safety and health concerns for the miners as well as people in downstream communities.

Jan 1, 2003

By Thomas E. P. Wechsler

The limiting factor for most pyro-metallurgical processes in secondary cop- per melting is the time required to heat and melt the product. American Combustion's proprietary PYRETRON variable £uel/air/oxygen combustion system improves the throughput of existing scrap melting and heating furnaces for copper and copper alloy production by increasing the rate of heat transfer from the flame to the product. The increased productivity and energy savings obtained from this technology can result in sizable reductions in operating costs for smelting operations.

Jan 1, 1991

By V. I. Lakshmanan

The demand for elements such as nickel, cobalt, titanium and gold in various applications has increased significantly. Innovation to recover these elements now plays a major role in metallurgical processes as established technologies have challenges in treating the types of ores that are available while meeting the increasingly stricter environmental regulations. Alternative chloride based processes have been developed that can be used to recover the value elements from the available feed stocks with potentially lower environmental impact. Chloride-based hydrometallurgical processes have several advantages, including higher leachability of complex ores/tailings and relative stability of chloro-complexes of the metals. Process Research ORTECH Inc. (PRO) has developed mixed-chloride process flowsheets, where innovative solvent extraction process steps are used for the separation of nickel, cobalt, titanium and gold from their respective chloride solutions. This paper will discuss the potential aqueous chloro-chemistry of these metals and separation reaction mechanisms involved in the solvent extraction process.

By Batric Pesic

Dissolution of gold with sodium bromate solutions of various compositions was studied by using a rotating disc technique. The role of bromide ion, acid and externally added bromine was examined. It was found that sodium bromate could not dissolve gold in the absence of either acid or bromide ion, or both. When acid was absent, no bromine necessary for gold dissolution could be produced. When bromide ion was absent, formation of soluble gold bromide species, AuBr,-, was not possible. Bromate concentration had a complex effect, and it was dependant on bromide ion concentration. For fixed initial bromide ion concentration, gold dissolution rate increased with sodium bramate concentration increase until certain level, beyond which further increase of bromate concentration decreased the gold dissolution rate. The negative effect of bromate was explained by the depletion of necessary bromide ion. Sulfuric acid concentration effect was a function of initially present bromine.

Jan 1, 1992

By Hsing Kuang Lin

Ferric chloride leaching w.as applied to a complex sulfide ore from Tok, Alaska to dissolve zinc, lead, silver and copper. Gold in the leaching residue, as well as in the ore, is found to be refractory to the conventional cyanidation process. Roasting, pressure oxidation and elemental sulfur removal followed by cyanidation were tested to improve gold dissolution. Also tested were thiourea leaching and high-pressure cyanidation. The readsorption of dissolved gold by carbonaceous matter in the chloride leaching residue was analyzed. Based on the experimental results, factors causing difficulty of gold dissolution from the leaching residue are discussed.

Jan 1, 1989

By O. C. Gaspar

The mineralogical and textural characteristics of the volcanogenic massive sulphide ores from the Aljustrel and Neves-Corvo deposits have been studied by ore microscopy techniques since 1977. Several ore types have been recognized, and the ore paragenesis, ore textures, and behaviours of different ore types during grinding and concentration processes, have been determined. An ore classification was established for use in metallogenetic studies, ore reserve calculations, selectivity during mining, and control of the ore beneficiation processes. In addition, an empirical method was developed for supplying, on time, the qualitative and semi-quantitative information needed for processing the Aljustrel ores and for optimizing the Neves-. Corvo copper and tin concentrators.

Jan 1, 1991

By Peter Woodall, Paul Telford, Pengfu Tan

"Arsenic enters the Mount Isa copper circuit in the form of arsenic rich minerals in concentrates from both the Mount Isa and Ernest Henry copper mines. Arsenic is a volatile metal, and will partition in the copper smelter between smelter off gases, slag and anode. Most of the volatile arsenic will report to Isasmelt Electrostatic Precipitator (ESP) or Waste Heat Boiler dusts where it will form a re-circulating load within the smelter. ESP dust is produced at a rate of 15,000 - 20,000 t/y and is currently removed from the precipitator and leached in the new ESP Dust Recovery Plant to separate copper and arsenic from the ESP dust. This paper describes the laboratory test works of ESP dust leaching, neutralisation and cementation processes. The planttrial, commissioning and operation have been presented as well.1. IntroductionThe flue dusts generated in the process of copper smelting contain appreciable amounts of copper and other valuable metals including precious metals. These flue dusts also contain appreciable amounts of arsenic trioxide where arsenic occurs in the ore body. The copper smelters processing concentrates generate residuals, such as ESP dust, containing arsenic trioxide. ESP dust contains impurities such as arsenic and bismuth which are harmful to the copper refining process if they report to anode. These impurities are fumed off in the smelting process and report to the dust as arsenic and bismuth oxides.The content of arsenic in the feed of Mount Isa copper smelter is about 0.1 % to 0.4%. Arsenic is a volatile metal, and will partition in the copper smelter between off gases and anode. Most of the volatile arsenic reports to Electrostatic Precipitator (ESP) and Waste Heat Boiler dusts where it will form a re-circulating load within Mount Isa Copper Smelter. Unless arsenic is bled from the smelter circuit, it will build up to a point where both anode quality and smelter hygiene are adversely impacted."

Jan 1, 2011

By Niels Verbaan

NioCorp is developing the niobium/scandium/titanium Elk Creek carbonatite deposit. The probable reserve announced by the company in 2017 indicated significant niobium (0.79% Nb2O5), titanium (2.81% TiO2), and scandium (71 g/t), and is composed predominantly of calcite, dolomite, and ankerite. Niobium is mostly (80%) contained in pyrochlore with the balance in various Fe-Nb-Ti oxides, which also host most of the titanium. Scandium is primarily deported in dolomite, with lesser quantities in pyrochlore and biotite. The process flowsheet recovers separate niobium, titanium, and scandium products. Scandium is extracted from whole ore hydrochloric acid leach solutions using solvent extraction and is further refined through a re-leach and precipitation process. Scandium leach residues are treated in a sulphuric acid sulphation process to recover separate niobium and titanium precipitates as well as to solubilize the remaining scandium. Both hydrochloric acid and sulphuric acid reagents are recycled within the flowsheet. This paper will discuss key bench and pilot test results of the niobium extraction and recovery circuits and will present a conceptual flowsheet developed by the project team for NioCorp at SGS Minerals.

By J. N. Hartley

Samples of ash from the May 18, 1980, eruption of Mt. St. Helens Were collected from several locations in eastern Washington and Montana. The optical microscope and the combined scanning electron microscope with energy dispersive x-ray microprobe were used to determine the composition and mineralogical characteristics of the samples. In addition, a quantitative image analyzer was used to examine the particle size distribution, and x-ray diffraction was used to identify major minerals. Both polished sections and ultra thin sections (less than 5 ~m in thickness) were prepared to study the mineralogical characteristics. The use of ultra thin sections provided access to microstructural detail. Mineralogically, the samples ranged from almost totally glassy to almost totally crystalline. Crystal-line samples were dominated by plagioclase feldspar (andesine) and ortho-pyroxene (hypersthene) with smaller amounts of titaniferous magnetite and hornblende. Nearly all the samples contained from less than 1 to 3 wt% free crystalline silica (quartz, trydimite, or cristobalite).

Jan 1, 1981

By C. Acuna

The standard procedure of fire refining consists of sulphur removal via air injected through tuyeres, arsenic slagging via soda-lime flux and oxygen reduction by air or oxygen deficient air or a steam fuel mixtures. The use of porous plugs to stir with an inert gas has been mainly considered as a surface renewing agent that increases the product quality and shorten the refining cycle. In the present study the effect of the bottom stirring by nitrogen gas injection through porous plugs for the treatment of the crude copper in the range of 400-150 ppm sulphur, 3,000?2,000 ppm arsenic and 14,000-7,000 ppm oxygen content was investigated. The combined effect stirring-reducing, by the use of air or a steam fuel mixtures through tuyeres for oxygen removal, follows a kinetics of first order where the constant, K, can be represented by the following polynomial expression: K = A .* R2 + B * R + C Where A, Band C are constants that depend on the nitrogen flow rate and R is the air-fuel ratio or the steam-fuel used in the reducing step. Depending on the optimization of the flow of nitrogen and the air-fuel or steam-fuel mixture and only if just the oxidation, complexing and reducing steps are considered, the process cycle might be shortened by 45%.

Jan 1, 2003

The standard procedure of fire refining consists of sulphur removal via air injected through tuyeres, arsenic slagging via soda-lime flux and oxygen reduction by air or oxygen deficient air or a steam fuel mixtures. The use of porous plugs to stir with an inert gas has been mainly considered as a surface renewing agent that increases the product quality and shorten the refining cycle. In the present study the effect of the bottom stirring by nitrogen gas injection through porous plugs for the treatment of the crude copper in the range of 400-150 ppm sulphur, 3,000-2,000 ppm arsenic and 14,000-7,000 ppm oxygen content was investigated. The combined effect stirring-reducing, by the use of air or a steam fuel mixtures through tuyeres for oxygen removal, follows a kinetics of first order where the constant, K, can be represented by the following polynomial expression: K = A * R2 + B * R + C Where A, Band C are constants that depend on the nitrogen flow rate and R is the air-fuel ratio or the steam-fuel used in the reducing step. Depending on the optimization of the flow of nitrogen and the air-fuel or steam-fuel mixture and only if just the oxidation, complexing and reducing steps are considered, the process cycle might be shortened by 45%.

Jan 1, 2003

By H. Y. Sohn, Joshua E. Ramos, Moo Eob Choi

"A new technology for ironmaking based on direct gaseous reduction of iron ore concentrate is under development. This technology would drastically lower CO2 emission and reduce energy consumption by nearly 38% of the blast furnace requirements. Experiments were performed using iron oxide concentrate at 1150oC in a bench-scale facility, which was the highest temperature that could be reached in the facility. The reduction extent was determined at residence times of 3.5 - 5.5 seconds in which the reduction extent approached 43% with 0% excess H2 and 95% with 860% excess H2. Separate kinetics measurements showed that the rate is much faster at 1200 - 1400 oC. Experiments were also carried out using syngas (mixtures of H2 + CO). About 90% reduction in 3.5 seconds with 860% excess hydrogen contained in the syngas demonstrated sufficiently fast reduction for a suspension process and the feasibility of usingsyngas instead of pure hydrogen.IntroductionDespite the improvements in the modern blast furnace (BF) process, it suffers from many drawbacks. The process requires the feed in the form of sinters or pellets and high-grade coking coal. Thus, BF iron production is projected to decrease gradually [1]. The main factors for this are the environmental regulations [2] and the high capital investment cost.A large number of new ironmaking technologies have been developed or are under development [3]. Most of these processes, however, are not sufficiently intensive to replace the blast furnace because they cannot be operated at high temperatures due to the sticking and fusion of particles. Therefore, a new technology is under development for producing iron directly from fine concentrates by a gas-solid suspension technology, which would reduce energy consumption by about 38% of the amount required by the blast furnace and drastically lower environmental pollution, especially CO2 emission, from the steel industry."

Jan 1, 2009