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By Thomas Niehoff

"Oxyfuel combustion systems are state of the art for many melting operations. Airfuel systems have been stepwise modified to oxygen enrichment, oxygen lancing and oxyfuel. Every change of the melting process will have consequences with regards to emissions and energy usage. The uniqueness of many operations requires unique skills to resolve potential issues. This paper will give some examples of how airfuel systems can successfully be converted to oxyfuel.IntroductionOxyfuel technology – meaning the combustion of fossil fuels such as natural gas, oil or coal with technical oxygen instead of air for industrial melting or heating processes is widely used in many industries these days. Even though oxygen production, storage and handling has been state of the art for decades other opinions exist. Often oxyfuel is regarded with fear and potential hazards like: “Oxygen makes the process too hot.”, “Oxygen will melt away the refractory.”, Liquid oxygen is dangerous.”, “Oxygen will cause explosions.”, ……etc.Typically a more detailed discussion about a specific industrial process and how oxygen can be applied in a safe and economic way the seeming issues go away."

Jan 1, 2010

By Gabriel Bartholazzi Lugão de Carvalho, Sergio Neves Monteiro, Fabio Da Costa Garcia Filho

The thermochemical treatment of Pulsed Plasma Nitriding is employed as an alternative to improve the surface properties of metals, such as: increase surface hardness, improve wear resistance, extend fatigue life and also create a barrier to the diffusion of hydrogen into the steel to reduce the susceptibility to hydrogen embrittlement. In this study, the effect of such treatment on ASTM A36 steel is analyzed through two different nitriding conditions: 5 h and 660 Pa for the first condition and 15 h and 720 Pa for the second one. In both cases, the temperature was held at 300 °C. Thus, in order to verify the results, Vickers hardness analysis and metallographic observation were carried out under an optical microscope. Only the second condition was able to achieve what was proposed, the formation of a uniform nitriding layer and an expressive increase of hardening on the surface.

Mar 1, 2018

By Henry Hu, Alfred Yu

"A numerical model has been developed to simulate heat and mass transfer phenomena occurring during a novel magnesium reduction process-the vertical retort technology. The model was based on the control - volume finite difference approach. Simulations were run to determine the effect of various processing parameters on magnesium reduction cycle time. The model predicted temperature distributions, heating curves, recovery ratio of magnesium, and total process times. The predictions were used to optimize the magnesium reduction process including dimensions of the retort, geometries of the reactant compounds, and productivities. The results indicate that the implementation of the optimized processing parameters significantly decreases the reduction time, and consequently increases the production rate as well as lowers the energy consumption.IntroductionMagnesium consumption has been growing considerably in the past decade [1]. Of the total magnesium production, 30% is produced by the thermal reduction (Pidgeon) process, and it is anticipated to be still the main technology for producing magnesium in future [2]. One of the advantages of the Pidgeon process is that it is capable of producing high purity magnesium demanded by both the automotive and aerospace industries. However, the inefficiency of heat and mass transfer taking place in the horizontal Pidgeon reduction process results in low productivity, high energy consumption, labor-intensive operation, large floor space and high capital investment. This limits the production scale of a horizontal Pidgeon reduction process [3].Vertical reduction processTo overcome the shortcomings of the horizontal magnesium reduction process, a novel vertical magnesium reduction process [3] for large-scale production has been developed, in which heat and mass transfer in the retort is enhanced. The new process shortens reduction time, reduces energy consumption and increases productivity. The vertical reduction system is comprised of a vertically-placed retort, a heating furnace and a vacuum system. A section of the vertical retort is illustrated in Figure 1. Since the retort is set vertically, instead of horizontally, the entire procedure of loading the reactants material in the new process is different from the one for the horizontal reduction process."

Jan 1, 2001

By Martin Fischer

A new method for the quantitative image analysis of complex microstructures in steel is presented. Microstructures in modern steel grades on the one hand become more and more complex while on the other hand the size of the constituents is scaled down ever further. For these reasons it is increasingly difficult or even impossible to access reliable quantitative information on ratios, shapes and spatial distributions of individual phases and constituents by utilising traditional metallographic analysis methods. The presented new analysis approach is object-based. Its basic processing units are so-called ?image objects? which reflect the pictured structures by merged groups of likely related pixels. By the use of image objects, information on shape, graphical texture and spatial distribution of the microstructural constituents can be processed. With these additional data available, it is possible to quantitatively analyse complex microstructures. This is demonstrated by the application of the method to SEM images of different multiphase steel grades. Because the analysis routine is fully automated, the analysis of large amounts of image data is possible and thereby the investigation of statistically relevant areas of microstructures.

Jan 1, 2009

By Zhi-xiang Cui

Effects of flux, vulcanizing agent and reductant on slag cleaning in new-type slag cleaning furnace (Φ3.6 × 8.1 m) were investigated under the conditions including smelting temperature of 1200 and 1250 °C, settling time of 30 and 60 min, and Fe/SiO2 of 1.7–1.9. The results show that addition of SiO2, B2O3 or CaF2 into original copper smelting slag can improve settling separation effect. Though no effect on copper recovery, addition of FeS can provide heat required by reaction with oxygen and reduce copper dissolution in spinel phase and slag. Copper content in discarded slag can be controlled at 0.26% under the optimum comprehensive conditions with ratio of oxygen to natural gas of 1.6.

By Susumu Okabe

Top blowing lances are employed by the Mitsubishi Continuous Copper Converter for the continuous supply Of reaction gases into moken bath. In order to minimize the refractory wear caused by the interaction between the furnace lining and the melt splash. optimum furnace design and blowing condition are? required. An empirical equation obtained by the physical model study enables the estimation of the splashing rate on a vel1ical plane at a certain distance from the lance.

Jan 1, 1996

By Honggang Zhong, Tan Yi, Qijie Zhai, Zhao Dan, Xinping Mao, Huigai Li

"The influence of superheat degree on the distribution and volume content of inclusions were studied in 65Mn thin slab produced by compact strip production(CSP) in Zhujiang Steel in China, The results showed that the diameters of inclusions are mainly less than 5µm. Most of the inclusions gathered at the 1/4 thickness direction for the thin slab of 27? superheat degree, compared with the center position for that of 37?. There are more inclusions larger than 50µm in the low superheat samples, which is caused by the short floating time. In addition, the inclusions were observed and analyzed by metallurgical microscope, SEM and EDS in order to ensure their composition, type and further find their source. It was find that the types of these inclusions mainly are Al2O3, SiO2,CaO and their composites, a few of them are TiN and MnS.IntroductionIt is well known that inclusions have a great impact on the strength, plasticity, fracture toughness, cutting performance, fatigue property and corrosion resistance of steels. Especially, with the demand for thinner slab, the cleanness is increasingly becoming more significant as a quality criterion[1]. High manganese and carbon steels not only demonstrate high strength but also proper plasticity. There are many problems unsolved for 65Mn steel as a result of the low solidification rate, bad thermal strength, crack sensitivity and low casting temperature[2,3].The superheat of the molten steel has a great impact on the erosion of refractory lining, molten steel fluidity and non-metallic inclusion behavior[4]. The serious erosion situation of ladle lining, nozzle and casting tundish will give rise to more inclusions at a high superheat. Meantime higher superheat will make second dendrite arm spacing coursing and element segregation which lead to inclusion, bubble formation and shrinkage cavity. On the contrary, it is hard for non-metallic inclusions to float up with a low superheat value. Inclusions of 65Mn steel, which produced in different superheat condition by CSP, were studied for the sake of higher slab properties including statistics and EDS analysis."

Jan 1, 2012

By David C. Lynch

FeCl3 particulate of 10 to 100 um in diameter was reacted with radicals produced in an oxygen plasma at pressures between 1 to 20 Torr. The particulate, in a fluidized bed, was positioned above the plasma to avoid over heating the oxide product which is known to lead to crust and clinker formation[ 1 ]. Reaction between the iron chloride and the gas phase occurred at temperatures between 66 and 226 °C. Oxygen radicals react with the surface material to a depth of approximately 2.5 4m. Surface material, analyzed with a x-ray technique, indicates that the maximum amount of FeCl3 reacted on a weight basis was found to be approximately 67%. More typically, 40 to 50 wt% of the chloride was reacted within 30 minutes to 1 hour.

Jan 1, 1996

By W. G. Davenport

Chapter 4 examined Inco (oxygen) flash smelting of pure chalcopyrite concentrate. It showed that the oxygen and flux requirements for auto thermal smelting are readily determined by a matrix calculation. This chapter extends this matrix approach by applying it to a multi-mineral concentrate.

Jan 1, 2001

By W. G. Davenport

All Outokumpu flash furnaces burn some hydrocarbon fuel. Hydrocarbon combustion supplements heat from Fe and S oxidation and provides local heating in cool; parts of the furnace. Adjustment of hydrocarbon fuel combustion rate is an effective way of controlling furnace temperature. More oxygen and more oxidation of Fe?and S in the flash furnace continue to diminish the need for1hydrocarbon fuel. Still, as Tables 2.1 and 3.1 show, all flash furnaces use it. Oil is the most common fuel -natural gas, coal and coke are also used. This chapter demonstrates how hydrocarbon fuel is included in our flash furnace matrix. It shows that: (a) three new variables, mass hydrocarbonfoel. mass CO2 in offgas and mass H2O in offgas are inserted (b) carbon and hydrogen balances are added (c) hydrocarbon fuel quantity is specified (d) ,the oxygen balance is modified to include CO2 and H2O (e) the enthalpy balance is modified to include hydrocarbon fuel, CO2 and H20.

Jan 1, 2001

By Thomas Niehoff, Yin Qing, Wei Zhongling, Liu Yongguo, Zhang Deliang, Tang Le

The gold ore of Shandong Gold Mining (Xinhui) was a refractory ore, which contained multi metallic sulfides (ZnS and PbS etc.) and carbonaceous. The gold ore concentrate came into leaching process and thickener and zinc replacement to recover gold. In order to improve gold recovery, the GOLDOX™ hydrometallurgy process was studied in Shandong Gold (Xinhui) by bench scale and 6 month plant scale test supported by Linde Gas. It was shown that the process promoted the leaching kinetics and improved gold recovery. The residue grade reduced 0.22 g/t in average after oxygen was applied. This indicates an operating profit increase 850,000 yuan/a in the plant. It was setting a good example for similar gold mine plant and would promote the oxygen application in Chinese gold mining industry.

Jan 1, 2015

By G. E. S. Lima, J. V. B. Lemes, F. G. D. Machado, S. Monteiro, L. G. Pedroti, L. A. F. Fioresi, W. E. H. Fernandes, R. C. S. S. Alvarenga

With advances in industrial processes, new products have emerged and become essential in everyday life. These activities generate different types of wastes, which can be harmful tothe environmentif not properly disposed. Having this problem in sight and considering the importance of concrete in the construction industry, this study analyzes the behavio of Reactive Powder Concrete (RPC) with addition of granite processing waste. Scanning Electron Microscopic (SEM) tests, compressive strength and Young’s modulus tests after 1, 3, 7 and 28 days of production and shear and flexural strength after 28 days of production were performed during the analysis. The results indicated that incorporation of this residue into RPC does not affect its performance. RPC was still able to present high compressive and flexural strength.

Mar 1, 2017

By Djalma Souza, Felipe Perissé Duarte Lopes, Frederico Muylaert Margem, Sergio Neves Monteiro

The development of composite materials is a combination of distinct materials, with applications in various areas, such as: aerospace, automobile, etc. Regardingmechanicalresistance,composites reinforced with a dispersion phase in a fiber form is more relevant. The green idea is use composites with natural fibers instead offiberglass, especially in non-structural applications. The Fique fiber has occupying an important place at Colombian agricultural and agribusiness sectors. Epoxy matrix composites reinforced with 1–6 Fique fabric layers were tested and the results indicated that thetensile properties improve with increasing theamount of Fique fabric layers. The fiber/matrix interaction was analyzed by scanning electron microscopy.

Mar 1, 2018

By Billy W. Osborne

The use or primary dross as a source for aluminum ion in the manufacture of aluminum sulfate offers opportunities for an inexpensive raw material. The aluminum sulfate industry in the US is a mature market with numerous small plants operating close to major users. The majority of manufacturers use either bauxite or aluminum oxide trihydrate as a source for the alum¬inum ion.. However, using process technology developed and patented by IWC, the oxides are removed from primary dross for use in manufacturing aluminum sulfate prior to metal recovery. This process offers the benefit of reducing costs for metal recovery. This paper discusses some of the methodology used in this process.

Jan 1, 1995

By Hoda Emami

In this study, a combined pyrometallurgical and hydrometallurgical technique has been designed and used to recover rare earth mixture elements (REE) and cobalt from a NdFeB magnetic waste. while addressing the cost of reagent and process facility. This process can be adjusted to different magnetic wastes regardless of their compositions. Prior to the leaching, the magnet scrap was pretreated by two rounds of roasting (750°C in air) and a mechanical grinding in between, to convert iron metal to ferric oxide. Subsequent leaching was performed using optimized conditions (pH, temperature and retention time) where the extraction ratio of REE to Fe III is the highest. After removing iron content from the leachate (pH ≈ 3), REE was precipitated selectively and purified further. The produced REE concentrate reaches 99% purity with 85% recovery in a single run. The cobalt oxide was isolated from the PLS as a by-product with 99.8% purity.

By Kenneth A. Brunk

"This address discusses how ""Mineral Processing Technology"" can play a major role in the life and profitability of a mining company. Examples of past and present technological breakthroughs and their impacts will be examined. Also, the future of processing technology will be emphasized.IntroductionThis talk will center on the role of technology as an important component of a business plan for mining companies. I'll attempt to explain how I see technology development as an underpinning of a successful mining company. We will examine an example of a technology that has resulted in a re-birth of segments of the industry, examine a technology life cycle and discuss technology as it relates to ore reserve replacement. Also, we will touch on technology in today's mining company and propose some food for thought for those designers of corporate organizations."

Jan 1, 1997

By G. Pantazopoulos, A. Vazdirvanidis

In this paper, a failure analysis investigation is presented concerning the intergranular cracking of three different diameter (Ø26.6, Ø10.8, Ø8.5 mm) high strength brass rods which failed after extrusion. Optical, Scanning Electron Microscopy and Electron Backscatter Diffraction are employed in order to reveal the mechanisms and the root causes of the failures. The microstructural characteristics, exhibited by the brass rods, pertaining mainly to phase, grain structure, size and distribution of intermetallic particles, are considered to exert a detrimental effect, impairing the mechanical properties, facilitating the environmentally-induced degradation and assisting the occurrence of brittle fractures. Revision of preheating and extrusion conditions could be further implemented in order to minimize the risk of such failure in the future.

Mar 1, 2018

By Giulio R. Altoé, Sergio N. Monteiro, Ygor M. Moraes, Rômulo L. Loyola, Frederico M. Margem, Gabriel O. Glória

The tensile properties of DGEBA/TETA epoxy matrix composites reinforced with different amounts of PALF fibers were evaluated. Composites reinforced with up to 30% in volume of long, continuous and aligned PALF fibers were tested in an Instron machine at room temperature. The fracture was analyzed by SEM. This one revealed a weak fiber/matrix interface, which could be responsible for the performance of some properties. The results showed significant changes in the mechanical properties with the amount of PALF fibers.

Jan 1, 2015

By Jason Ganley, Yingjia Liu, Adam Dekich, William Tilson, Jeffrey Fergus, Dileep Kumar CJ

"Manganese cobalt spinel oxide coatings have been shown to be effective for preventing chromium volatilization from interconnect alloys, and the associated cathode poisoning, in solid oxide fuel cells. During high temperature exposure a reaction layer consisting of chromium containing spine! forms due to reaction with the chromia scale formed on the alloy. The electrical conductivity of this reaction layer is much lower than that of the coating material and thus can increase the overall area specific resistance (ASR) of the system. The approaches to reducing the ASR are to reduce the thickness and/or increase the electrical conductivity of the reaction layer, which includes both the high-chromium spinel phase and the chromia scale. In this paper the effects of transition metal dopants on the amount and properties of reaction products formed during the reaction of spine! oxide coating materials with chromia are presented.IntroductionThe high cost and difficulties involved with the processing of chromia based ceramic interconnect materials for SOFCs are driving the search for metallic interconnects [1, 2]. The reduction in the operating temperature of SOFC has allowed for the use of high chromium alloy steels for this application [3]. However, the volatilization of chromium from the chromia scale, and the associated poisoning of the cathode, remains a problem which needs to be addressed [ 4]. Though the application of manganese cobalt oxide spine! coatings on the alloy surface substantially reduces chromium poisoning of the cathode [5], the low electrical conductivity of the reaction layer formed between the chromia scale and coating affects the performance of interconnect. Incorporating transition metal ions in the reaction layer could alter the electrical characteristics and improve the performance. Copper and nickel doped manganese oxide spinels are widely used as thermistors due to their high electrical conductivity and negative temperature co-efficient of resistance characteristics [ 6, 7]. Hence doping of copper and nickel in manganese-cobalt spine! oxide composition may improve the electrical characteristics of interaction layer as well and is attempted here."

Jan 1, 2012

By Wei-Tong Du, Zheng-Lei Guo, Yu Wang, Shu-Chao Wang

The influence of bottom blowing a CO2–O2 mixture on the bath temperature of a vanadium extraction converter was studied by using the characteristics of CO2 with weak oxidizing. It was studied in two aspects: oxygen content and temperature. The experiments showed, when the ratio of the mixture of CO2–O2 was 2:8 at 1300 °C, the bottom blowing of the converter inhibited the heating up of the hot metal, thus keeping the temperature below the carbon vanadium transition temperature. At 1360 °C, the sensible heat absorption by CO2 was 1.44 times that absorbed by O2 per mole. Meanwhile, at 1300 °C, 20% CO2 released the chemical heat of 13.58 kJ. So with the increase of the CO2 ratio, the bath temperature was reduced. The research showed that the bottom blowing of a CO2–O2 mixture had an advantageous effect by decreasing the temperature of the vanadium extraction converter.

Mar 1, 2018