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By J. K. Brimacombe

"Nearly all the easy things have been investigated in injection metallurgy. Water models have been used exhaustively to study mixing, gas distribution and flow in submerged jets. Mathematical models have been developed with their restrictive boundary conditions to quantify submerged gas jet behavior. While being valuable tools to our understanding of injection metallurgy, there is an obliqueness to their application. What we need now are measurements and modelling on the actual systems, hot and unfriendly, where gas meets liquid at temperatures above l000°C. This is where the challenge lies.AN APPRECIATONThere are those who follow the trail and there are those few who blaze new trails in search of novel concepts and processes. With his restless, inventive mind, Howard Womer is a trail blazer without doubt. Decades ago, he was a pioneer in the pursuit of continuous steelmaking with the WORCRA Process and, today, he is developing new processes for the treatment of waste. He is not only an inventor but has been a professor at the University of Melbourne and was the first Director of Research at BHP. He has influenced the lives of many people, including myself; with his achievements and humanity. Therefore it is most fitting that this symposium should be held in honour of Howard Womer, a luminary in the metallurgical world for over half a century.BACKGROUNDGas injection has been an integral part of pyrometallurgical processes since the early days of Bessemer, then of Pierce and Smith. Today, of course, one cannot imagine pyrometallurgical processes without submerged gas injection to effect reactions for metal extraction and refining, to provide mixing and to inject solids into molten metal, slag or matte. Spurred on by new developments like tonnage oxygen and argon production, the Savard-Lee concentric tuyere and porous plugs, new steelmaking processes have emerged; and now solids injection is changing copper extraction processes. The ingenuity of the extractive metallurgists who drove these developments is inspiring for they have applied gas injection to transform pyrometallurgical processes. Humankind has been the beneficiary.' Today these processes are safer, more efficient, cost effective, less energy intensive and more environmentally friendly."

Jan 1, 1996

By Michael P. Heisel

Solinox is a physical scrubbing process capable of removing a number of noxious materials from off-gasses, especially SO2, hydrocarbons, halogens, heavy metals such as dust, etc. As these materials are dissolved physically, (not chemically bound), the solvent is absolutely stable and no by-products are formed in the scrubbing cycle. The process has? been installed in three plants up to now, treating from approximately 30 MMSCFD to approximately 100 MMSCFD. These installations are in a non ferrous metal smelting operation, in a cellulose factory, and in a roasting process.

Jan 1, 1992

By Tuneo Funahashi

Sumitomo Shisaka Works has been treating EAF(Electric Arc Furnace) dust to recover zinc and lead in the Waelz Kiln process. Since its commencement of operation in 1977, many technical improvements have been successfully made to increase the production capacity and the zinc recovery rate. The EAF dust charge to the Waelz Kiln was increased from 35,000tly to 120,00OtIy, and the production of zinc oxide now amounts to 40,000tly. The zinc content in the clinker was decreased from 5% to less than I%, by the optimization of the kiln heat pattern with no accretion trouble. And the clinker has become more a valuable raw material for steel making. This paper describes the above progress ofthe SMM Waelz Kiln process operation at the Shisaka Works.

Jan 1, 1998

By LeRoy C. Prichard

The scrap based steel producers in the United States generate an estimated 650,000 tons of electric arc furnace (EAF) dust annually which is classified as hazardous waste, K061. These scrap based producers commonly referred to as mini-mills represented 39% of the steel produced in 1994. Based upon the EAF plants being installed or planned today, it is a reasonable projection to anticipate 50% of the steel produced in the United States will be by EAF's. Using a straight line projection of percent of steel produced to tonnage of EAF dust generated, this will result in 833,000 tons of dust being generated upon the completion of these new EAF producing plants, presumably by the year 2000. Because the United States is a capitalistic economy, a steel producer is in business to make a profit therefore dust management becomes a very important variable in the cost of making steel. An EAF mini-mill dust management program must consider at least three components. First the handling of the dust must be in accordance with the law; i.e., the Environmental Protection Agency rules and state and local municipalities guidelines governing K061. Second, it must be an economical solution that allows a company to manage its dust processing costs, a component of its total steel production costs while producing steel at a profit. Third, the dust management program should be one that is environmentally responsible; viz., the program should reclaim or recycle the dust constituents, as feedstock materials or saleable products. The first component, obedience of the law seems to be a relatively straight forward, common sense objective; however, as nearly every mini-mill operation will testify it has been a area of changing laws with confusing variations when it comes to K061. Even more frustrating is the fact that obedience or compliance today does not mean that the company will be considered law abiding in the future.The liabilities associated with

Jan 1, 1995

By Wan Pu

Chrysotile asbestos samples from different mines have been studied by SEM and TEM, including high resolution electron microscopy, to find reasons for differences in physical properties of different types of asbestos fibres. The results show that the inner diameters of fibre tubes and the lattice images of fibres are different for soft and hard asbestos fibres. These differences are related to temperatures and geochemical conditions during the growth of chrysotile asbestos.

Jan 1, 1989

By Gary K. Elliott

Many industrial processes generate hot waste gases which contain particulate pollutants. Conventional clean-up techniques suffer limitations either because collection efficiency is low or because the gas must be cooled before treatment. thereby increasing costs and preventing energy recovery. The application of increasingly stringent environmental legislation to the non-ferrous metallurgical industry is presently illustrating these conventional technology limitations. Low density ceramic media allow filtration to ta,ke place at 'high temperatures and are now rapidly becoming accepted In many industries. This paper reviews experiences with a proprietary low density ceramic filter element. CerafH. It includes consideration of the structure, composition. typical operating and case studies with particular reference to non-ferrous metallurgical furnace applications.

Jan 1, 1992

By Kohei Yajima

The dusts and fly ash generated from the steelmaking processes and municipal solid waste incineration processes contain metallic elements such as Fe, Zn, Pb and Cd with considerable amount of halogens. In Japan, zinc in dusts is recovered by Waelz kiln or MF process, etc. However, the presence of halogen in the dust affects the evaporation and condensation behavior of zinc and other metals, and disturbs the direct recycling of dust to steelmaking processes, because alkali or heavy metals reacted with halogen vaporize easily as halides and/or oxyhalide compounds in pyrometallurgical process. Recently, the formation mechanism of zinc oxychloride vapor was investigated and the formation of zinc oxychloride such as ZnOCl was proposed. However, considering the practical operation, the effect of water vapor on the evaporation behavior of oxychloride is not fully clarified yet. This study is focused on the investigation of evaporation behavior of ZnO with Ar- O2-HCl-H2O atmosphere.

Jan 1, 2008

By Zhigang Liang

Effects of the configuration parameters of submerged entry nozzle on the flow field in slab mold were investigated through a water modeling. The experimental results showed, when the original submerged entry nozzle was applied, there was an appreciable level fluctuation in the mold with obviously naked surface and entrapment of mold flux at higher casting speed. By increasing the outlet area of submerged entry nozzle, without any change of other configuration parameters and submergence depth, a proper fluid field with active surface and good covering of mold flux can be obtained, which is proper to meet the requirement for increasing the casting speed and improving the slab quality simultaneously.

Jan 1, 2009

By E. C. L. Cardoso

Hydrocarbon polymers, as PP, made from cheap petrochemical feedstock are important in many branches of industry. However, they have an undesirable influence on the environment and cause problems due to waste deposition and utilization. Polymeric materials composites account for an estimated from 20 to 30% of total volume of solid waste disposed. Thus, there is a tendency to substitute such polymers by those ones that undergo biodegradable processes. Polypropylene (PP) is a commodity, with high melting point, high chemical resistance, low density, with a balance between physical and mechanical properties and easy processing at low cost. Nevertheless, PP shows limitations for some special applications in automotive industry and civil construction. In order to minimize this deficiency, related to rheological behavior of polymer melt, especially referring to viscosity in processing temperature, a 50% mixture with HMSPP (High melt Strength Polypropylene) was used. PP/HMSPP was blended with 10, 15, 30 and 50% of natural (sugarcane bagasse) and synthetic polymers (PHB and PLA) aiming to partially biodegradable materials. The admixtures were subjected to gamma-irradiation at 50, 100, 150 and 200 kGy and then further assessed by mechanical tests in order to evaluate their degradability.

Jan 1, 2015

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

By C. Segawa

SMM operates an original slime treatment process for recovering precious metals and other metals (Te,Se,Sb,Bi)from the copper and the lead anode tankhouse slimes. In recent years, the amount of slimes has increased and the pyrometallurgical processing units capacity became the bottleneck of the entire plants. For the expansion of the plant, new pyrometallurgical facilities, incorporating a BBOC, was commissioned in 1992 and has now been successfully operated. In addition, unit operations were optimized to increase recovery and reduce operating cost .. The results of modifications made in the plant are discussed in this paper.

Jan 1, 1996

By Shaik Jeelani, Esperidiana A. B. Moura, Vijaya K. Rangari, Roberta A. Lima, Rene R. Oliveira

This work present the preparation and characterization of biodegradable nanocomposites based on aliphatic-aromatic copolyester (PBAT)/polylatic acid (PLA) blend reinforced by TiO2 nanoparticle. The biodegradable polymeric nanocomposites were prepared by melting extrusion process using a twin-screw extruder machine. The influence of the TiO2 nanoparticle addition on mechanical and thermal properties of PBAT/PLA blend was investigated by tensile and impact tests, SEM, DSC and XRD analysis and the correlation between properties was discussed.

Jan 1, 2015

By Shaolong Chen, Carl-Gustav Berg, Hannu Mansikkaviita

Kumera Steam Dryer has been developed particularly for nonferrous metal concentrates with steam as heating source generated from waste heat boilers. Its unique structure enables the dryer to work at high capacity, up to 240 t/h, and high availability, over 95%. With half a century of engineering experience, and more than twenty industrial steam dryer installations worldwide during last 15 years, Kumera has demonstrated significant benefits of the steam drying technology in terms of energy efficiency and emission reduction to the end users. The dryer of this type can also be applied for other suitable mineral materials.

Jan 1, 2015

By Dongping Duan, Hongliang Han, Li Zhong, Siming Chen, E Zhou

In this study, physical, chemical and microscopic characteristics of Celestine were investigated firstly. Based on which, the thermodynamic analysis of Celestine reduction was discussed. And the experiments of Celestine carbon-containing pellets used in rotary hearth furnace process were studied. The results showed that it is feasible to deal with Celestine by rotary hearth furnace direct reduction process. When the temperature is 1200°C, C/O ratio is 0.8 and holding times is 20min, the conversion rate of SrSO4 in Celestine is above 95%, the utilization rate of Celestine is nearly 100%. This study can provide theoretical and technical basis on economical and rational use of Celestine.

Jan 1, 2016

By C. Abruzzese

This work concerns a process for the inertization of asbestos-containing wastes and the subsequent recycling of the inerts for the production of ceramic refractories. One of producted refractories is cordierite, that is widely used in the electronics industry and also in mechanical engineering for the manufacture of catalytic converters for automobiles. The process thus achieves the twofold objective of eliminating toxic and harmful refuse containing asbestos, while making available high-tech materials at a reasonable cost.

Jan 1, 1998

By Takeshi Azakami

By combining the iron reduction process with the usual rotary kiln process, the direct production of metallic zinc from EAF dust is proposed. After thermodynamic estimation and desk-top experiments it is confirmed that the process is hopeful under suitable conditions. In order to get some practical test data the enlargement of the process scale was planned and the bench scale tests were carried on successfully. In these experiments a zinc ingot of PW grade was produced from EAF dust.

Jan 1, 2003

By Y. Moriya, Y. Sadayoshi, Y. Nonogaki, Y. Takeda

"Preparation and growth processes of CaF2 on Si(111) and of . InxGa1-x,As islands on CaF2 by molecular beam epitaxy (MBE) are described. It was found that first of all the Si(111) surface treatment process to obtain the 7x7 reconstructed structure was necessary to ensure the cleanness of the surface and to grow a flat and high quality CaF2 on it. Growth of InxGa11-x,As islands on CaF2 was tried by droplet heteroepitaxy using the same MBE reactor. In,GaxGa1-xAs islands were successfully grown epitaxially, and the size and density of the islands dependent on the In composition were investigated.IntroductionThough semiconductor/semiconductor heterostructures are widely used for many device applications, small band off-sets of the conduction bands and the valence bands restrict the utilization of the intra-subband transitions to far-infrared regions. With InAs as the quantum well and fluorides as the barrier layers, we can design three-electronic-level systems in the infrared region, which is the low loss transmission window of the silica optical fibers. To realize those structures, we have grown InxGa1-xAs islands on CaF2 thin films that were epitaxially formed on Si(111) substrates by molecular beam epitaxy. By the droplet heteroepitaxy that we invented, the InxGa1-xAs islands with height of -10 nm have been obtained successfully. Optimum processing to obtain atomically smooth surfaces of Si and CaF2 and high quality InxGa1-xAs islands is reported.ExperimentsMBEMachineCaF2 was grown on Si(111) and InxGa1-xAs islands were grown on CaF2 successively by MBE. The MBE machine consisted of a growth (or reactor) chamber and a loading chamber. The reactor chamber was equipped with Ga, In, As and Er metal source cells and CaF2 and BaF2 source cells. Cell materials were P-BN for Ga, In and As metals, and were graphite for CaF 2, BaF 2 and Er to avoid reaction with BN cells. The electron gun and screen were attached to the reactor to observe the RHEED pattern during the substrate surface treatment and the growth of CaF2 and InxGa1-xAs islands. The substrate manipulator was designed to heat up the Si substrate up to 1,200°C for the surface cleaning. The QMS was also equipped to analyze the residual gas species in the reactor chamber. The base pressure of the reactor chamber was 2-5x10-11 Torr, being pumped by ion pump and the liquid nitrogen shroud"

Jan 1, 2000

By F. Shen

Qualitative and quantitative results obtained during the physical modeling of the molten aluminum flow in a tundish using an aqueous system are presented. Surface tuft, free-surface powder and laser sheet visualization techniques were utilized for qualitative studies, whereas laser Doppler velocimetry was used to elucidate the 3-D flow regimes quantitatively. The results of the study are used for validation of the CFD codes, and to explore the effect of the alterations below the nozzle in order to: (1) decrease turbulence levels, and (2) collect the inclusions. Near the nozzle, the interaction of the impinging jet and the inclined walls gives rise to vortex structures. Downstream of the nozzle, two counter-rotating secondary cells diminish in strength. As flow turns through the bend, a separation region is created. The flow heading into the closed duct is seen to be nonsymmetric. A video tape highlighting the major findings is presented.

Jan 1, 1993

By Hideki Yamamoto, Junji Shibata

"The chemical reactions of fluoride and chloride gases with metal chloride or metal oxide are utilized as an effective treatment for harmless disposal. These chemical reactions can be adopted in the temperature range of 80°C~400°C, which is lower than that in the combustion treatment (800°C). Reaction products are metal fluoride or metal chloride which are a harmless and a valuable chemical material as one of new resources. This paper, concerns with a new harmless disposal treatment of toxic global warming gases.IntroductionNew technology to make fluoride and chloride gases such as NF3, CF4, SF6 BF3, Cl2 and BCl3 harmless has been developed and a new concept on the removing toxic gas to be used in the advanced process of materials has been established. The fluoride gases ~re toxic and special type of gases to be used in the process of manufacturing semiconductors and their specific applications include the dry etching of semiconductors, cleaning of CVD systems, an oxidation agent for rocket fuel etc. Especially, NF3 is also attracting an attention as a high-energy source for chemical laser systems. As a fluoride gas like NF3 is, however; toxic and highly stable chemically, if discharged into the atmosphere, it is liable to cause far-reaching adverse influences on global warming in the same manner as carbon dioxide gas and feron gas.Up till now, the combustion treatment method has been adopted for the disposal of the gas, and when treating the gas by high-temperature combustion (800""C), the generation of nitrogen oxides (NOx), sulfur oxides (SOx) and hydrogen fluoride (HF) have been confirmed: These chemical substances are not only linked with an intense c0rrosion of the combustion systems but also create the generation of atmospheric pollution and acid rains, and therefore, constitute a serious social issue."

Jan 1, 2000

By Mei Song, Qingyu Deng, Xuewei Lv, Lu Liu, Chenguang Bai, Meilong Hu

"The carbochlorination of several silica materials was carried out in the temperature range from 900 °C to 1200 °C. In this study, silica oxides and gaseous chlorine with carbon as reductant were used. The optimal carbon silica mole ratio in different temperature was calculated by Factsage software and the results showed that the optimal values are 1.2, 1.4, 1.6, 1.8 at 900 °C, 1000 °C, 1100 °C, 1200 °C, respectively. According to the experiments, the chlorination ratios of several silica materials were increased with temperature increasing. In the same temperature, the chlorination ratio of diatomite is the maximum and the chlorination ratio reaches 79%% when C/SiO2 reaches 3 at 1100 °C.1, IntroductionPolycrystalline silicon is the main material to manufacture the silicon polished section, solar battery[1] and high purity silicon wafers[2], also which is the most basic function material of semi-conductor industry, electronic information industry and solar photovoltaic battery industry[3]. The conventional manufacturing process of polycrystalline silicon would be divided into three parts: the improved Siemens method, which was introduced and became the main process to produce the polysilicon products in China. Silane method and fluidized bed method. Silicon tetrachloride and chlorosilans have been employed as by-products in several fields like electronic, telecounications and metallurgy[4-6]• At present, the main applications of silicon tetrachloride include production of trichlorosilane by catalytic hydrogenation, synthesis of fumed silica and ethyl orthosilicate, production of optical fiber grade silicon tetrachloride.The conventional routes for the silicon tetrachloride production have been reported, including the direct chlorination and the chlorination process of ferrosilicon, abandon catalyst and silica[7]."

Jan 1, 2013