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By Sun Ying, Zhang Jing, Li Qiu-ju, Wang Yan-ze

Copper smelter slag was leached using sulphuric acid solutions under atmospheric conditions. Base on the composition and phase of copper slag, the effect of the concentration of sulfuric acid and leaching temperature to the leaching growth rate of Fe, Cu, Co and Ni in the copper slag were investigated in this paper. Simultaneously, the influence of sulfuric acid concentration, leaching time, leaching temperature and the amount of sulfuric acid (solid-liquid ratio) to the leaching rate of these metal elements were researched. Experimental results showed that: with the increasing temperature, the dissolution rates of the metals elements increased first and then decreased. Due to the influence of silica gel which was obtained in beginning of leaching, the higher the concentration of sulfuric acid is not conducive to dissolution of the valuable metal elements. The dissolution degree of Fe, Cu, Co and Ni were 92.83% 96.76% 93.62% and 63.41% respectively.

Jan 1, 2016

By Cao rong-jiang, Tang Xin-he

"In ordinary manufacture process of tungsten powder, a preferable intermediate product used is ammonium paratungstate (APT). The particle size of tungten powder made from it through W2OO58 is larger than 1. 0 um. In order to obtain ultrafine tungsten powder with narrow size distribution, a new type of tungstate, hydraziniull tungstate, was studied. Its formula is 5(N2H5)2O·12 WO.s , with tetragonal crystal structure of a=5.821 , c=18. 468. Three methods for preparing hydrazinium tungstate (ART) were set up and ART can be produced by current industrial APT process with little modification of operation and without any change of equipment.Under certain PH and operation condition of the solution from which ART was produced, an autoreduction of tungsten occured, which produced a lower valency tungstate with blue color when ART was heated at different temperatures, in N atmosphere, tungsten bronze, tetragonal W0290 and W02.7E could be obtained respectively. They all have the superiorities, in the production of tungsten powder, of superfine size and narrow size distribution [average size of 0.5um or even smaller.The rate of autoreduction of ART is very fast at elevated temperature. The reduction reaction, which gaves tetragonal WO290, could be handled smoothly without explosion. To research their behaviors at autoreduction temperatures and the products of autoreduction will be new advances of tungsten chemistry and may also serve tungsten industry with new processes and materials."

Jan 1, 1988

By R. W. Bartlett

A two step process for treating platinum group metal flotation concentrates Is described while experimental results. The process was designed to be simple and Inexpensive While yielding a high recovery and fast turnaround. Ii consists of electric furnace smelting of concentrate to remove gangue and produce a homogeneous sulfide matte containing all of the base metals and platinum group metals. Sulfide oxidation Is minimized during smelting to avoid Installing an acid plant In the second step, matte Is pressure-leached with oxygen In an acid sulfate system to dissolve Iron, nickel, ?and copper while leaving a residue highly concentrated In precious metals, and typically about 1% of the flotation concentrate mass, A batch process with oxygen titration against the base metal composition of the feed Is used to control the end point of the leach. Sulfides must be eliminated while minimizing the precipitation of hydrolysis products. The leach residue can be smelled to bullion to facilitate sampling accuracy.

Jan 1, 1989

By WenCai Li, Yong Ren, Shuai Niu, Xin Hong

"Temperature measurement is very important in metal smelting process. Many devices are used to realize non-contact temperature measurements. Compared to conventional thermocouple, infrared temperature measurement has it's unique advantages. However, using an infrared temperature measurement at the top of the furnace can not obtain the desired optical signal because of disturbance from slag layer, high-temperature gases and other effects. A real time thermometry system with dual-wavelength radiation was presented to get optical signal emitted from molten metal through bottom-blowing nozzle. Taking into account the advantages and disadvantages of bottom-blowing devices, a MHP (Multiple Hole Plug) bottom-blowing device was used, through which the optical signal was transferred to the infrared thermometer by use of optical fiber. After conversion and analysis in real-time, the result was displayed and recorded in computer. After calibration, it could be a good predictor of temperature trend in a metallurgical process. IntroductionAt the refining stage of steelmaking, in order to achieve predetermined chemical composition and temperature, high-temperature molten steel is refined in a furnace such as converter. Because the refining process involved with chemical components and reaction velocities in the furnace rely on the temperature of steel, it is necessary to know the temperature accurately in real time during the process. And temperature measurement is also helpful for the end-point judgment. The temperature in the refining process changes quickly, for instance, in a converter, 300t molten steel is processed in only about half an hour.At present, traditional way of temperature measurement is using a thermocouple probe mounted on a lifter called a sub-lance. The thermocouple is immersed in molten steel and its temperature is measured during the short period until the thermocouple is fused. Accurate and reliable temperature can be obtained by this method, but in consideration of the discontinuous measurement and the costs, missing the end-point temperature may sometimes occur.According to the above background, a method in which a temperature-sensing element such as a thermocouple is immersed directly in molten steel is not suitable for the continuous temperature measurement because materials having such stability are not available. Therefore, radiation thermometry is promising. There have been some reports on radiation thermometry through an observation nozzle through the bottom or side of a refining furnace [1, 2]."

Jan 1, 2014

By L. J. Cabri

The level of mineral exploration activity for platinum in recent years, especially in North America, has ranged widely. Exploration programs have been based on a variety of ore deposit models and deposit types. These range from the classic magmatic model for sulfide/oxide deposits and their associated placers, through hydrothennal models for bonanza-type deposits, to low-grade mineralization potentially amenable to lower cost bulk mining methods. The platinum-group element (PGE) distribution in these different deposit types is not well-known however, and PGE determination is fraught with analytical difficulties. To properly assess a prospect or to achieve effective recovery by mineral processing, it is important to determine the mineralogical distribution of the PGE.

Jan 1, 1988

By P. M. Swash

This paper reviews the application of some mineralogical techniques in the evaluation of the Uitkomst Ni-Cu deposit, South Africa. The low grade of the ore necessitates detailed and representative characterisation in order to establish the prospects viability. The relevant mineralogical information is generated by using optical microscopy, magnetic and heavy liquid . separations, XRD. SEM and EMPA. Methods used are briefly reviewed. The cost savings and metallurgical understanding that is provided by the mineralogical work is described especially with regard to milling, flotation and the presence of by-products (PGMs and chromite).

Jan 1, 1991

By James A. Voigt

The efficient separation of metal species from aqueous streams by precipitation techniques requires 'a fundamental understanding of the various processes that occur during precipitation. These processes include particle nucleation, particle growth by solute deposition, agglomerate formation, and agglomerate break-up. The application of the population balance approach has been used to develop a kinetic model that accounts for these competing kinetic processes. The usefulness of the model is illustrated through its application to the precipitation of yttrium hydroxynitrate, YHN. The kinetic parameters calculated from the model equations and system-specific solution chemistry are used to describe several aspects of the effect of pH on the precipitation of the YHN. Implications with respect to the simultaneous precipitation of more than one cation type are also discussed through use of example systems: The effects of solution chemistry, precipitator design, and solvent choice are considered.

Jan 1, 1996

By T. Sakaguehi

Some attempts were made to recover and remove of uranium that may be present in refining effluents, mine waste Water, and other waste sources by using microbial biomass. To establish which microorganisms accumulate the most uranium, 135 species of microorganisms (42 bacteria, 26 yeasts, 34 fungi and 33 actinomycetes) were screened. Of these 135 species of microorganisms tested, extremely high uranium absorbing ability was found in Pseudomonas stuzeri, Neurospora sitophila, Streptomyces albus and Streptomvces viridochromogenes. In addition to the research on uranium uptake, thorium recovery by using microorganisms was investigated. High abilities were found in Streptomyces levoris and Bacillus subtilis. The selective accumulation of heavy metal ions by various microorganisms has also been examined. Uranyl, mercury and lead ions were readily accumulated by almost all of the species of microorganisms tested. Actinomycetes and fungi differ from many bacteria and most yeasts in their selective accumulation of uranium, and mercury. The basic features of uranium uptake by Streptomyces viridochromogenes, a microorganisms with high uranium-uptake ability, were investigated systematically. Synthesizing these results, we suggested that the accumulation of uranium into these microbial cells is not directly mediated by any metabolic process:, but almost completely dependent upon physicochemical adsorption on the cell components. In addition to this fundamental research, uranium recovery was investigated in immobilized Streptomyces viridochromogenes. These immobilized cells adsorbed, uranium readily and selectively. The immobilized cells recovered uranium almost quantitatively and almost all uranium adsorbed was desorbed with 0.1 N Na2CO3, These results showed that microbial cells are more stable after Immobilization and can be used repeatedly for the process of uranium adsorption-desorption. These results suggested that these microbial cells can be used for the recovery and removal of nuclear fuel elements, such as uranium and thorium, from refining effluents and mine waste water.

Jan 1, 1991

By I. Gaballah

The electrochemical behavior of a chalcopyrite concentrate having a high pyrite content was studied in HC1 by potentiodynamic, potentiostatic and galvanostatic experiments using a cell having separate anodic and cathodic compartments. Anodic oxidation of chalcopyrite particles was realized both by their contact with the cunent feeder and by reaction with ferric and cupric ions. An increase of current leads to a more selective dissolution of chalcopyrite. Surface passivation was observed after an electrolysis time related to the cell current. Cathodic reduction of chalcopyrite concentrate seems to be more promising. Almost complete conversion of chalcopyrite to a copper sulfide (Cui.8.S) is observed, whereas no reaction of the pyrite was detected. This confirms the possible selective dissolution of copper from the chalcopyrite concentrate. Copper sulfide obtained by cathodic reduction was leached using a cupric chloride solution.

Jan 1, 1994

By Huimin Lu, Min Li, Jinghua Zou

"Zeolitic imidazolate frameworks (ZIFs) are new type of porous materials, form inerratic polyhedral in three-dimensional with large cages and small apertures, and appear structural diversity. Their hole size can be adjusted. These materials have high selective adsorption capacity to carbon dioxide. In this paper, zeolitic imidazolate frameworks were synthesized by solvothermal synthesis method with dimethylformamide (DMF) as solvent and structuredirecting agent, divalent metallic ions as cation, and imidazole as ligand. The crystals were characterized with XRD, SEM for their crystal structures and physical properties, the adsorption of the crystals for carbon dioxide was also tested, and the result suggests that these porous materials have a capacity of 1.35ml/g for storing carbon dioxide at 273 Kelvin under ambient pressure.IntroductionGlobal warming caused by the increase of carbon dioxide in the atmosphere has become one of the main environment problems, contemporary research has focused on ways to slow or stop this trend. CO2 capture has attracted attention due to the potential to trap and sequester large amounts of CO2 from concentrated sources such as power plants [1]. Traditional technologies in capturing CO2 include absorption by aqueous amines [2]. However, utilization of this process is energy intensive and expensive. Carbon dioxide storage materials investigated so far can be divided into two categories: chemical storage adsorbents and physical storage media [3]. The first kind of materials can chemically adsorb carbon dioxide within their structures and need thermal energy to release the adsorbed carbon dioxide. The examples of the chemical adsorbents include aqueous amines, gas-hyperbranched aminosilicas [4]. The physical adsorbents store carbon dioxide by physical adsorption of carbon dioxide at elevated pressure and release the adsorbed carbon dioxide at low pressure. The physical adsorbents that have been investigated for carbon dioxide storage include zeolites, carbonaceous materials and other porous materials. Until recently, a new type of microporous material, known as zeolitic imidazolate frameworks (ZIFs), has been reported as promising adsorbents for carbon dioxide storage [5 ~ 10]."

Jan 1, 2010

By Bradford C. Wesstrom, Omar Araujo

"Impurities from an electrolytic refinery are typically extracted from the electrolyte utilizing conventional electrowinning cells. These cells are arranged in series with cascading solution flow and are commonly referred to as liberator cells. The Freeport McMoRan Copper & Gold El Paso Refinery has optimized the removal of arsenic in cascading liberator cells by utilizing two separate feed solutions. The primary feed solution is recycled liberator electrolyte and the secondary feed solution is ""neat"" tank house electrolyte. The secondary feed solution is added based on the voltage response across the individual cells utilizing independent variable frequency drive (VFD) pumps. When the voltage across a cell changes, a signal is sent to the VFD pump to maintain a cell voltage of 1.98 volts. By maintaining this voltage the copper content in each cell exits at 2-4 grams per liter. This safely optimizes the arsenic removal as copper arsenides on the liberator cathodes.IntroductionDuring the electrolytic refining of copper, impurities from the copper anode report both to the bottom of the electrolytic refining cell as slimes and to the electrolyte. The impurities which enter the electrolyte are arsenic, antimony, bismuth and nickel. The impurities that report to the electrolyte during the electrolysis process gradually increase. As these impurities increase, they are incorporated into the refined copper cathode. There are many processes that have been used to remove these impurities from refinery electrolytes. Some of them are listed as follows: solvent extraction, ion exchange, hydrogen sulfide reduction, bioreactor, adsorption onto a low - solubility metal-oxide hydrate, adsorption onto activated carbon and EMEW cells. The conventional process used by the copper refining industry for controlling the level of impurities in electrolyte involves multistage electrolytic cascading liberator cells. In these cascading liberator cells copper, arsenic, antimony and bismuth are removed as various mixed deposits from the electrolyte. Removal of these impurities is achieved through an increase in voltage resulting from the depletion of copper in the electrolyte through electrowinning. With this higher voltage, the Group Vb elements, arsenic, antimony and bismuth are deposited on the copper cathode and report as slimes to the bottom of the cells. Nickel is removed in a subsequent process."

Jan 1, 2012

By WU Jian-hui

Keywords: metallic material; nickel powder; thermal decomposition; precursor; fibrillar powder; nanometer scale; passivation treatment The precursor thermal decomposition process of fibrillar nanometer scale nickel powder and passivation treatment of obtained powder are investigated, and the composition and morphology of the products are characterized by use of IR, TGA/DTA, XRD and SEM. The results show that the precursor morphology is a decisive factor to the product morphology of the nickel powder. The morphology of the product derived at low decomposing temperature is irregular. The nickel powders produced at the temperature higher than 480 coheres seriously. The product particles are reunited with the decomposition time prolong. The powder prepared under the optimal condition is fibrillar like woolen yarn; the grain diameter is less than 50nm.

Jan 1, 2005

By K. Kalgraf

The motion and stability of the metal/electrolyte interface is determined by Navier-Stokes equation. The equation may be decomposed into two independent equations by taking the divergence and curl of Navier-Stokes equation. The divergence determines the motion and stability of magneto-gravitational waves. The curl of Navier-Stokes equation gives an equation containing only velocity and magnetic field, and states that the magnetic field is driving a circulation pattern in the cell, and this magneto-flow has its own stability conditions. The waves are called Alfven waves, and their stability properties are related only to magnetic field and geometry.

Jan 1, 2001

By Juan H. Rojas C.

The Chuquicamata mining and metallurgical complex is the main Division belonging to Corporation Nacional del Cobre de Chile (CODELCO-CHILE) and it accounts for 50% of the 1.4 Mt of fine copper output of the Corporation. It has been producing copper since 1915. The paper refers to the challenges that Chuquicamata has to solve in the near future. These challenges are: the increasing operation costs associated to a 800 m depth pit with low prices in an overstocked copper market; the increasing people's sensitivity to environmental preservation; and, the transformation needed for achieving high levels of organizational effectiveness. According to Corporate policy, Chuquicamata is making efforts to switch from a management style focused on supply to a management style focused on demand side of the industry. In this direction is tempting to establish strategic alliances to develop both new copper products and uses, to rise the metal demand. In more than 80 years of operation, Chuquicamata had exploited just one third of its geological resources. The exploitation of the remaining two third is a huge engineering challenge, taking into account the depth of the deposit, the impurities content, the decreasing ore grades and the transportation distances for waste dumping. All those factors are relevant in the economical process of transforming geological resources into ore reserves. Chuquicamata has other limitations. First, a 20,000 people town just aside the pit that limits the mining rates because of dust generation; second the scarceness of water in the desert area where Chuquicamata deposit is located; and, finally, the new tailing pond is a problem which solution will demand huge engineering efforts and investments. People are the principal factor associated to a company success. In this field, Chuquicamata have been progressing, but much more efforts from people will be necessary to reduce production costs for being successful as any other price-taker within the copper industry. Chuquicamata must develop the skills of its Supervisors to transform them into leaders and entrepreneurs, who additionally have the challenge of passing on their knowledge to non-professional workers. It is an ethic commitment to assure personal and professional growth of workers, as the only sustainable way to get real and integral success.

Jan 1, 1999

By Helena Byrdziak

Polish Copper Industry, located in the Lepica-Glogów region and operated since the 1970's, includes four mines and two smelters, "Legnica" and "Glogów", the latter consisting of "Glogów" I" and "Glogów II" both having different technologies. The "Legnica" and the "Glogów I" smelters using shaft furnaces, so sulfur elimination largely takes place during batchwise converting, resulting in fluctuation SO2-concentration between less than 1% up to 10% in the converter pas W the sulfuric acid plants. The ensuing difficulties of the past have now largely been overcome. Introduction of flash smelting at "Glogów II" with subsequent acid making by double SO2-conversion from the stable process gas, contributed significantly to further reduction Of SO2-emission. In 1994 a new double conversion sulfuric acid plant was installed at "Glogów l" as well as a "Solinox" desulfurisation plant at "Legnica", further reducing SO2 emission considerably, The next step towards this goal under consideration is a semi-dry desulfurization system for the "Glogów I" power station, SO2- abatement measures by KGHM and the results thereby achieved are presented.

Jan 1, 1996

By George A. Calboreanu

In order to overcome drilling and tapping of high hardness wear resistent material in slurry pumps, most of time mild steel inserts are mounted in the mold and after pouring they become an integrated part of the casting. This process is limiting the size and design possibilities of slurry pumps and efforts were made to drill and tap the hard iron itself. The paper will present practical results obtained in drilling and tapping Cr-Mo wear resistent material with hardness in excess of 700 HBN. The life time of the slurry pump parts used in hazardous waste fuel transportation with high slurry velocity and 15% solid loading some of it being quartz, increased 2.5 to 6 times.

Jan 1, 1996

By Florian Kongoli

"Lime ferrite" slag with limited silica content has proven to be a valuable choice in the modem processes of copper smelting and converting due to several advantages that this slag offers compared to classical silicate slags. Nevertheless the liquidus surface of this slag has been experimentally measured only at low oxygen potentials such as in equilibrium with iron or near it and in air. Although most of the smelting and converting processes that use this slag occur at intermediate oxygen potentials, the liquidus surface of this slag is not known at these conditions and the effect of oxygen potential and silica has not been correctly understood. This has brought some confusion in literature as well as in the industrial practice. In this work the liquidus surface of the calcium ferrite slags has been quantified by the means of a new thermophysicochemical model and a new type of liquidus surface diagrams which are very convenient for any industrial process that uses calcium ferrite slags. These diagrams can be easily used to select the lowest liquidus temperature of calcium ferrite slags at a minimum cost and can help design several fluxing strategies in copper smelting and converting processes. The effect of the oxygen potential and silica is also quantified and important industrially related conclusions are drawn.

Jan 1, 2003

By Florian Kongoli

"Lime ferrite" slag with limited silica content has proven to be a valuable choice in the modem processes of copper smelting and converting due to several advantages that this slag offers compared to classical silicate slags. Nevertheless the liquidus surface of this slag has been experimentally measured only at low oxygen potentials such as in equilibrium with iron or hear it and in air. Although most of the smelting and converting processes that use this slag occur at intermediate oxygen potentials, the liquidus surface of this slag is not known at these conditions and the effect of oxygen potential and silica has not been correctly understood. This has brought some confusion in literature as well as in the industrial practice. In this work the liquidus surface of the calcium ferrite slags has been quantified by the means of a new thermophysicochemical model and a new type of liquidus surface diagrams which are very convenient for any industrial process that uses calcium ferrite slags. These diagrams can be easily used to select the lowest liquidus temperature of calcium ferrite slags at a minimum cost and can help design several fluxing strategies in copper smelting and converting processes. The effect of the oxygen potential and silica is also quantified and important industrially related conclusions are drawn.

Jan 1, 2003

By Chu Yong Cheng

Manganese is one of the main impurities in the recovery of base metals from their ores. This is especially true when laterite ores are processed using the pressure acid leach (PAL) process. The use of intermediate precipitation, solids/liquid separation and re-leach in the three Western Australian nickel laterite plants to separate nickel and cobalt from manganese and other impurities makes these processes complicated and costly in capital and operation. The research work carried out by the solvent extraction (SX) group at the A J Parker Cooperative Research Centre for Hydrometallurgy (CSIRO Minerals) has led to the development of direct solvent extraction processes to separate nickel and cobalt from manganese and other impurities. The simplicity of the process flowsheets and the expected savings in capital and operating costs are the major advantages of the new direct solvent extraction processes over the existing processes. By using a new synergistic organic system, Versatic 10 / dccyl-4-pyridinccarboxylatc ester, with a pilot plant leach solution from BHP¬Billiton (after iron precipitation), the metal values (Ni and Co) together with zinc and copper were separated from manganese and other major impurities (Mg, Ca and Cl) in the first SX circuit. The co-extracted manganese, magnesium and calcium were easily scrubbed out. The extraction and stripping kinetics of the metals with the new synergistic organic system were very fast and the synergistic system was found to be chemically stable. pH-extraction isotherms of metals with D2EHPA showed that the extraction order as a function of pH50 was Zn2+ > Ca2+ > Mn2+ > Cu2+ > Co2+> Ni2+> Mg2+. Semi-continuous test work with a cobalt pilot plant leach solution from Peko Rehabilitation Project Pty Ltd and a synthetic solution to simulate a concentrated laterite leach solution from BHP-Billiton showed that manganese, together with calcium, copper and zinc can be separated from nickel, cobalt and magnesium. This led to the development of another direct solvent extraction process to separate manganese and other impurities from nickel and cobalt and to recover nickel and cobalt from leach solutions. A project was initiated by HiTec Energy Ltd to recover manganese from waste laterite leach solutions using SX technology and to further purify it to produce high purity electrolytic manganese dioxide (EMD) for the high quality alkaline battery industry. Batch tests were conducted to select a suitable organic system for the extraction of manganese in terms of selectivity and extraction and stripping kinetics. A total of eight organic systems were tested using waste laterite processing solutions. A Versatie 10 / synergist system showed very promising results. By using the synergistic system, high manganese recovery would be obtained, fewer SX stages would be required and a higher A:O ratio could be used in extraction, resulting in a smaller organic inventory and lower capital costs. The risk of gypsum formation is also minimised with the synergistic system. Keywords: Solvent Extraction, Manganese, Laterite, Synergist

Jan 1, 2004

By A. Elizabet Serna

The weak acid is a by product obtained in a pre-treatment of gases from a copper smelter prior to sulfuric acid manufacture and the main components of this weak acid are: sulfuric acid. copper, arsenic. antimony, bismuth and iron. Usually, this effluent is neutralized with lime and the solid residues are stored in a landfill as a hazardous waste. This work was directed at determining the optimal conditions to recover copper from weak acid using a cementation process before the neutralization of the effluent. The variables investigated are: Effluent temperature, iron scrap amount and acid concentration versus reaction time. The results of these experiments show that the cementation process of copper and the co-cementation of impurities such as arsenic, antimony and bismuth were in accord with the theory of the electrode potentials.

Jan 1, 1996