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By Congcong Yang, Jian Pan, Deqing Zhu, Yang Zhong

A study of pelletization of one imported chromite concentrate with coarse site, poor ballability and refractory roasting performance was conducted in small scale tests, and high pressure grinding rollers (HPGR) was used to improve the pelletization. The mechanism of HPGR was revealed by means of SEM images and optical microscopy. Compared with the ball milling pretreatment, HPGR pretreatment can not only enhance the ballability of pellet feed but also drop the roasting temperature. Fired pellets, containing proper chemical compositions with high compressive strength of 2917N/pellet and good metallurgical performances, have been manufactured. The mechanism of HPGR reveals that chromite particle surface turns to more irregular after HPGR treatment and more new surface being formed because of more cracks, sharp corners and edges appearing, resulting in higher surface chemical activity, all of which improve the ballability of the chromite concentrate and contribute to the consolidation of fired pellets.

Jan 1, 2015

By Nobuhiro Ishikawa

The in-situ observation of the effect of impurities on the reduction process of iron oxides by C in TEM was carried out. A few wt% of CaO or AbO, was used as impurities in FeO was prepared. Some precipitates grew into the C layer expect for using 3.0wtCa. The reaction between FeO and carbon was much different from using pure FeO at about 800-1 lOOK. The rate of reaction became much slower including Ca and almost no reaction was happened with the concentration of CaO up to 3.0wt%. On the contrary, AbO, had ahuost no effect on the reaction. The results indicated that Ca suppressed the reaction and the effect of Al was much less. The precipitates which grew into C layer accompanied almost no Ca and AI. Only Fe was detected in the precipitates.

Jan 1, 2008

By Jack A. Simon

My remarks are directed at relating some of the mineralogical approaches mentioned in the preceding presentations to emerging energy issues. The assembling of this symposium on process mineralogy attests to the growing concern for energy development from the non-petroleum mineral fuels and the unconventional petroleum fuels. A report in 1979, prepared under the auspices of the National Research Council/National Academy, of Sciences, was published in two parts and dealt with "Redistribution of Accessory Elements in Mining and Mineral Processing." This report rather comprehensively considers broad aspects of minerals associated with the solid fuels considered in this symposium and focuses attention on some problems of process mineralogy relative to these fuels. Papers have dealt with coal, oil shale, tar sands, and uranium minerals. Problems associated with mining, processing, and use of these materials have significant differences, but also have some factors in common relative to the subject of this symposium.

Jan 1, 1981

By Min Chen

A numerical simulation of the stress field of the solidified shell in the mold during continuous casting of peritectic steel slab was calculated with commercial software. The results showed that the maximal stress on wide face of the solidified shell was located at the corner and near middle of the slab, and it increased with increasing the width of slab. In addition, the stress was also influenced by operating parameters such as superheat degree, drawing speed and cooling intensity of the mold, and the maximal stress value and its position changed with these parameters. For the slab with section size of 3200mm×150mm, the proper drawing speed was around 1.2m/min, with cooling intensity of 5500L/min while the superheat degree was 15°C to 25°C in order to prevent longitudinal crack occurring during peritectic steel continuous casting.

Jan 1, 2009

Convential smelting of copper - cobalt - iron sulphide concentrates result in th eoxidation of cobalt and iron, which are subsequently lost into the slag. The emission of SO2 bearing gas from smelting causes serious health and environmentsl problems. In this investigation, three different types of copper - cobalt - iron sulphide concentrates, derived from froth flotation, were investigated, the concentrates, each containing more than 40 wt % percent gangue material, were directly reduced in the presence of lime and corbonin the temperature rnage of 1073 K - 1573 K, fo rthe production of an alloy containing copper, cobalt and iron. We demonstrate the basic principles of process physical chemistry for the recovery of alloy by carrying out a detailed process analysis utilising the predictions from thermodynamic equilibrium and results from the kinetics of reduction reaction. The effect of temperature on the reduction kinetics and alloy formation were determinedand analyzed in detail.

Jan 1, 2012

By S. Vukcocic

A long term research project is in progress to establish the parameters of an acid leach process to recover alumina 'froui' high-iron and/or low-iron white bauxites, kaolinite, coal. ash and copper mine tailing. In this paper the results of acid leaching of copper flotation tailing for the removal of alumina are presented. The tailing is very complex material which contains 25% Al203 in the -10 lim fraction. X-ray diffraction indicates presence of quartz, kaolinite and minor 'alunite. After classification and ,separation of the -10 lim fraction, the raw material is fired to 550GC and leached at 90GC. Filtration is applied for the separation of white silicate residue form leach liquid. After the purification step, aluminum salt is crystallized from the solution, and calcined to alumina. Kinetic correlation and regime, of the processes are defined and presented in the paper.

Jan 1, 1992

By D. L. Stewart

"Melt loss is usually one of the highest individual cost items in the operation of ah ingot casting facility. While melt loss and the resulting cost for the entire facility is usually well known (at least via standard cost accounting), dross generation and melt loss for individual unit operations within the plant are usually not known. Thus, the financial impact of various practices, alloys and scrap types is not known. Development of an accurate, relatively low-cost technique for measurement of melt loss at commercial scale would aid in understanding melt loss for existing units, as well as evaluation of the melt loss impact of alternate processes.This paper will describe a methodology developed at Alcoa for accurate and inexpensive measurement of melt loss at commercial scale. The methodology has been used to evaluate the impact of scrap type, melting practices, and dross treatment technology on melt loss."

Jan 1, 2000

By Adam Gesing, Ron Dalton, Richard Wolanski, Larry Berry, Christopher Stewart

As the quantity of aluminum recovered from shredder scrap continues to increase, together with increased content of aluminum in automobiles, so does the economic incentive to further upgrade shredder scrap. This upgrade will be done by sorting and recovering the aluminum by specific usable alloy compositions. The metal recycling industry infrastructure needed to deal with the increased aluminum scrap supply already exists. It is an inverted pyramid structure that in North America comprises: 3000 scrap collection yards, 200 shredders, a dozen sink-float plants and one heavy metal sorting operation. The technology for upgrading aluminum sorted from shredder scrap is already either in industrial use or in the final stages of pilot plant development. However, the current automotive aluminum recycling infrastructure will need to adjust to deal with higher volumes of the metal from aluminum-intensive vehicles that will be appearing in shredder scrap -20 years from now.

Jan 1, 2000

By Jonathan A. Paul

The most profitable companies in the world recognize that a huge competitive and financial power lies in their intangible assets. The competition to be in command of raw materials and markets is now waged more and more over the exclusive rights to new technology and ideas. The value gained from mining the innovation in your organization and protecting your intellectual property can be enormous. This paper will address the following topics: ? Understanding the connection between your competitive position and intellectual property ? Determining the value of your current portfolio and strengthening protection ? Converting knowledge into assets and adding value to the operation ? Litigation strategies to enforce your position and achieve your business objectives The presentation is designed for company executives and government managers who need to know how to identify and address core intellectual property issues that arise in the minerals, metals and materials extraction and processing industries.

Jan 1, 2006

By Kejun Liu

Platinum and palladium are usually dissolved together and followed by separation. In this study, the selective leaching of platinum and palladium from a secondary resource, such as dental waste, by using chloride solution (hypochlorite and chlorate) has been developed. Results indicate that about 100% of palladium could be initially extracted by the combination of 0.3 mol/L sodium hypochlorite (NaClO) and 0.068 mol/L sodium chloride (NaCl) at pH 1.2 and 298K in 1.5 hours, or the combination of 0.005 mol/L sodium chlorate (NaClO3) and 6 mol/L hydrochloric acid (HCl) at 298K in 0.5 hour. About 100% of platinum could be extracted from the residue by the combination of 0.47 mol/L sodium chlorate (NaClO3) and 12 mol/L hydrochloric acid (HCl) at 298K in 2 hours.

Jan 1, 2003

By Min Chen, Nan Wang, Zhen Tian, Yingying Shen

"The enrichment behavior of phosphorus in CaO-SiO2-FeOx-P2O5 slag was studied by making an investigation on the distribution of phosphorous content in slag and 2CaO·SiO2 phase. The research results showed that the existing 2CaO·SiO2 solid particles in slag were the sites for the phosphorous enrichment. The enrichment process of phosphorus in CaO-SiO2-FeOx-P2O5 slag can be recognized as: mass transfer of phosphorus from bulk slag toward the surface of 2CaO·SiO2 particle, superficial dissolution reaction of phosphorus to 2CaO·SiO2 and diffusion of phosphorus through the product layer of 2CaO·SiO2-3CaO·P2O5 solid solution to the inner of 2CaO·SiO2 particle. Compared to the 2CaO·SiO2 particles with larger size (500µm to 1000µm), the completion time of enrichment was shorter for the particles with smaller size (less than 50µm).IntroductionDuring ironmaking and steelmaking, significant amounts of slag are produced. Contrast to the high utilization of ironmaking slag, the treatment of steelmaking slag is more difficult and challengeable, and therefore, an alternative approach is to recycle the steelmaking slag inside the ironmaking and steelmaking process itself. The main limitation to the reuse of steelmaking slag inside the process is that the refining process may be aggravated caused by the phosphorous accumulation if it is used in the blast furnace burden [1]. At the same time, the phosphorous content of steelmaking slag (approximately 1%~5% P2O5) is too low for it to be used as raw material for fertilizer [2, 3]. Moreover, owing to the diminishing supply of global iron ores with low phosphorous content, the control of phosphorus in iron and steelmaking processes has become an increasing problem, and as a result, more amounts of high phosphorus containing steelmaking slag are produced. Therefore, a valuable approach is quite appreciated in which the steelmaking slag is recycled within the ironmaking and steelmaking process and at the same time, the high phosphorus-containing phases in the steelmaking slag, suitable for use as fertilizer can be separated and recycled effectively [4]."

Jan 1, 2011

By Mingmei Zhu, Xin Qiu, Xiaofei Dou, Yu Wang, Tiancheng Lin, Bing Xie

In this study, the slag forming route of the single-slag steel melting when smelting medium phosphorus hot metal was investigated. The CaO-SiO2-FeO-MgO-MnO-P2O5 as hexahydric slag system was adopted in the converter. The effect of slag composition on liquidus was calculated by FactSage, the isogram of phosphorus distribution ratio was calculated by using the regular ion solution model, combining these two tasks, the theoretical slag forming route was obtained. Through experiments, the actual melting point ofthe corresponding components on theoretical slag forming route was obtained, in this way, the theoretical slag forming route was confirmed. Then, the theoretical slag forming route was applied to industrial test in a 210t BOF. After using the new slag formating route, the dephosphorization ratio was increased 3.6% while the auxiliary materials consumption was reduced, and the cost of steelmaking was reduced.

Jan 1, 2015

By Shengli Wu, Mingyin Kou, Feng Chang, Laixin Wang, Hua Lu, Jianliang Zhang

Sintering dust has been regarded as an important secondary resource in a modern steel plant. Sintering dust was mechanically treated using different milling machines and experimental conditions in air atmosphere. The changes in phase constitution, particle size, specific surface area, particle morphology, and lattice parameters of activated sintering dust were determined. It was found that the agglomeration of the particles take place during extended dry milling with accessible pores for Nitrogen gas. The maximum specific BET surface area in the stirring wet grinding and planetary wet grinding increases to 43.06 and 46.45 m2/g after activated 360 min respectively. With the increasing of energy input, the intensity of diffraction peaks of dolomite and hematite gradually decreased. Furthermore, the previous phase almost disappeared eventually under any experimental conditions. In addition, Fourier transform infrared spectroscopy indicates that organic matter and carbonate decompose easier than other phases, especially under stirring wet milling.

Jan 1, 2016

By Wang Dawan

During the process of arsenic bearing gold concentration biooxidation, the content of chloride ion in water is a very important factor to the activity of bacteria and the oxidation of sulfide minerals. In this paper, the influence of underground mine water with different chloride ion content to the biooxidation of arsenic bearing gold concentration and the limit of chloride ion content to bacteria were summarized. These results indicated if the content of chloride ion was less than 1.2g/L, the bacteria?s ability to oxidize sulfide minerals was little affected, and if the content of chloride ion were increased to 2g/L or more, the activity of bacteria was seriously restrained, and if the content of chloride ion were increased to 4g/L, the activity of bacteria was absolutely restrained. So, as the content of chloride ion in water was cumulated to 2g/L or more in biooxidation plant, the water must be refreshed to maintain normal production.

Jan 1, 2008

By Chao Zhang, Jian Guo, Chaoquan Yao, Leige Xia, Xinyu Li, Jianliang Zhang

In this research, analytical reagents were used for the sintering experiments. And the sinters were using X-ray diffraction, scanning electron microscope and mineralogical microscope analysis to study the effect mechanism of manganese on the silico-ferrite of calcium and aluminum (SFCA) bonding phase formation during the sintering process. The results indicated that the increasing content of manganese would greatly reduce the content of SFCA, and promote the formation of calcium aluminum silicate and the amount of pores and cracks. The existence of manganese inhibited the silicon form into the SFCA and a great deal of Fe2O3 was participated in the crystal transition to Fe3O4. When the ratio of the added manganese was less than 3% in the mixing, the calcium ferrite was in substantially interleaving corrosion with hematite and magnetite. Both the porosity and silicate glass phase content were low simultaneously, which contributed to the sintering production.

Jan 1, 2015

By Lei Zhang, Shining Chen, Lina Wang, Pu Liu, Benquan Fu, Jiannyang Hwang

A three-dimensional (3D) electrode reactor combined with Fenton reagent was used for advanced treatment of coking wastewater from secondary biological treatment. Effects of some key factors on total organic carbon (TOC) removal rate were investigated, and the results were compared with those of the common three-dimensional electrode reactor. Experimental results showed that TOC removal rate could reach 51.7%, when optimal operating conditions were as follows: initial pH value 3.5, H2O2 dosage 17.6mmol/L, reaction time 90min and FeSO4·7H2O dosage 3.5mmol/L. Analytical results from UV absorption spectra indicated that the organic substances in the coking wastewater were well degraded by this system, which provided good experimental basis for the practical application of this process in the treatment of coking wastewater. This can be meaningful for the treatment of other kinds of wastewater.

Jan 1, 2015

By J. Rajesh Kumar

The extraction equilibrium study of tetravalent platinum was carried out using tri-octyl/decyl amine (Alamine 336) and bis(2,4,4-trimethylpentyl) monothiophosphinic acid (Cyanex 302) in kerosene from hydrochloric acid media to investigate their extraction capacity, since they have different donor atoms, ?N? and ?S?. Their distribution equlibria were studied as a function of acid, extractant, diluents and temperature. The title metal shows the inverse behavior at higher acid concentrations. Extraction of tetravalent platinum increases with increase of extractant concentration. The plot of log D vs. log [Extractant], mol.L-1 is linear with slopes 1±0.3, indicating the association of one mole of extractant with the extracted metal species. Stripping of metal from the loaded organic (LO) with mineral acids and bases such as hydrochloric, sulphuric, nitric acids and ammonia, hydrogen peroxide, sodium hydroxide, thio- urea were studied. Regeneration and recycling capacity of Alamine 336/Cyanex 302 and extraction behavior of associated elements was also studied.

Jan 1, 2009

By Cheng Yan, Yugang Li, Qian Wang, Lizhi Zhang

In continuous casting process, mold powder has lots of metallurgical effects, such as covering the molten steel to prevent liquid steel from oxidation by air, preserving heat for top layer liquid steel, lubricating initial shell and so on. However, mold powder also can deteriorate the quality of final products obviously after the entrapment of mold powder in steel. In the present work, based on the similarity theory the effect of technological parameters on mold powder entrainment was investigated by water model. Experiment was carried out in the water mold using oil and water to simulate slag and steel, respectively. The results showed that increasing casting speed increased the water-oil interfacial fluctuation and entrainment frequency; viscosity of oil also had a great impact on the interface fluctuation and entrainment; water-oil interfacial tension effect the entrainment while not changing the interfacial fluctuation; submergence depth had little impact on entrainment and interfacial fluctuation.

Jan 1, 2015

A full-scale test of chalcocite heap bioleaching was undertaken at Straits? Nifty Copper Operation. Straits worked closely with the CSIRO to investigate the chemical and biological changes over the life cycle of this chalcocite heap bioleach system. Results indicated nearly 80% copper recovery was achieved in just over 300 days. Significant changes in iron chemistry and microbiological activity were detected. Temperatures in the heap reached as high as 70 ºC during the time of maximal copper recovery rate. The dominant cultivatable bacterial strains were typical mesophilic bacteria, however, naturally occurring moderately thermophilic bacteria were detected by culture and culture independent molecular (PCR followed by denaturing gradient electrophoresis [DGGE]) and signature lipid methods. Signatures for the iron and sulfur-oxidising species Acidithiobacillus ferrooxidans and Sulfobacillus spp., as well as the moderately thermophilic heterotroph Alicyclobacillus sp. were detected. Biomass was greatest in ?warm? but not ?hot? parts of the heap, and Hyperthermophilic Archaea were not detected.

Jan 1, 2003

Iron(II), sulphur dioxide and sugars such as lactose are potential reducing agents for manganese dioxide to produce manganese(II) for subsequent hydrometallurgical treatment. The leaching of limonitic laterite and manganiferrous ores with sulphur dioxide produces iron(II) which in turn can catalyse the leaching of manganese dioxide in acid media. This paper presents a critical analysis of the kinetics of reductive dissolution of synthetic manganese dioxide and manganese ore to compare and contrast the effect of sulphur dioxide and iron(II) in acid media containing sulphate or perchlorate anions. Both one-electron and two-electron mechanisms are considered in the case of sulphur dioxide. The current knowledge on chemical speciation is used to construct an Eh-pH diagram to show the effect of complexation of Mn(II), Fe(II) and Fe(III) with sulphate. Heterogeneous and electrochemical reaction kinetic models are combined to propose reaction mechanisms which rationalize the dissolution kinetics.

Jan 1, 2003