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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 Helena Byrdziak

KGHM Polska Miedz SA, in existence since nineteen seventies, operates three underground mines and three smelters with total production of over 400 000 mtpy of electrolytic copper. Its impact on the environment, very serious in the past, has been gradually reduced. While in general emissions into the air and water have been brought under control, attention recently has shifted to the disposal of wastes and residues. The main streams of wastes are flotation tailings, slags and dust captured from the dedusting systems. Much effort has already been expended and is still being spent to utilize this waste for by-products production or to dispose of it within the process by recycling. The most effective measures taken up thus far, as well as present activities directed at tailings disposal, are presented.

Jan 1, 1997

By S. B. . Tyrrell

This paper describes research carried out to develop and optimise a process to extract lithium from the processed waste of spent lithium ution of lithium salts can be used to produce a pure lithium hydroxide solution, From this, lithium carbonate is produced, the major precursor for other lithium chemicals and for new lithium batteries. Hence, the recycle loop can be closed. Significant variation in the composition of the battery waste has been observed. Small amounts of metals other than lithium and certain anions can present technical difficulties such as electrode dissolution and membrane fouling. Pre-treatment of the waste, together with an optimum combination of cell materials and operating parameters has been found to enhance separation and alter the energy consumption of the process.

Jan 1, 1999

By C. Lupi

Electric arc furnace dust generated during the production of steels is regarded as hazardous waste because of the presence of leachable elements such as Cr, Pb, Cd .... Different processes are available according to the management policy chosen by the steelmaker: disposal. recycle and/or recovery. The feasibility of an hydrometallurgical Zn recovery process on fumes generated during the pyrometallurgical treatment of EAF dust has been investigated. The recovery of metallic iron, chromium and nickel as molten metal provides fumes very rich in zinc oxide ( 63.1% ) and poor in zinc ferrite. This secondary dust is still an hazardous waste and represents the raw material for the recovery of Zn and Pb. The waste material is first leached in 1.5 M sulphuric acid at 30°C to provide a Zn, Fe and Mn rich aqueous solution and a Pb and Ca sulphate rich sludge. The iron is eliminated by precipitation because is harmful to the following electrowinning process. The ftltered and purified leached solution is acidified in order to obtain good electrowinning conditions. A pure cathodic deposit of zinc is then produced in an electrolytic cell at laboratory scale.

Jan 1, 1996

By H. Masuda

The lijima Zinc Refinery started operation in 1972, and has today an annual capacity of 200, 000+-Zn. The hematite process was employed for the first time and the ideal of waste-free refinery has been pursued for 30 years. In recent years, however, only half of the hematite produced would be sold to the cement industry and hence a reduction of arsenic level has been necessary in order to sell the entire amount produced, The arsenic cementation process with zinc powder, developed through a long time laboratory research was found among some options as the best for the hematite process. The construction work started in 2000 and the facility was put into operation in 200 I. As a result in the same year all hematite were sold to the cement industry. The outline of this project, present operations and technical issue are reported in this paper.

Jan 1, 2003

By Jun Iwai, Osamu Takai, Yasushi Inoue, Hiroyuki Sugimura

"Infrared reflection absorption measurement was performed during plasma-enhanced chemical vapor deposition of silicon dioxide films at room temperature. Hydrocarbon contaminants adsorbed onto growing film surface are oxidized by oxygen radicals in plasma resulting functional groups which include C=O and C-O bondings. These groups exist only near the surface and are hydrolyzed rapidly after exposure to air.IntroductionRecently low-temperature silicon dioxide (SiO2) deposition has been in a growing industrial demand in pa1ticular, polymelic substrates such as polycarbonate and polyethylene telephthalate, which have poor heat resistance, need low process temperature (near room temperature) in coating of SiO2 which is a suitable material to improve optical and mechanical properties of polymenc products. Plasma enhanced chemical vapor deposition (PECVD) using organosilicon reactants is one of the most promising technique for lowering process temperature, so that it has been extensively studied1-12. In the present; however, hydrocarbon contaminants and a plenty of Si-OH termination in Si-O-Si networks tend to exist in the films, which degrade mechanical, optical and electrical properties of the films. It is necessary to understand the deposition mechanism at, low temperature in order to solve the problems. We have studied the low-temperature PECVD of Si02 by spectroscopic diagnosing techniques such as optical emission and mass analysis6-7, 11- 12Infrared reflection absorption spectroscopy (IR-RAS) has been a well-established technique for characterization of thin films on metals as· well as on semiconductors and insulators13-17. In this paper, we report on' the surface reaction of room-temperature PECVD of Si02by using in situ IR-RAS."

Jan 1, 2000

By Gary A. Wickham

In the zinc industry, this past decade has seen both prosperity and depression. Significant changes have occurred throughout the world in mining, smelting, refining, and marketing. This paper will review many of the industrywide changes of recent years and the potential impact for 1990s. In addition to an historical review of supply and demand are discussion of technology considerations for zinc and zinc based products, effects of geographical shifting of markets, and projections for the 1990s.

Jan 1, 1990

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 Toshiaki Nakai, Kunihiko Takeda, Kimio Imaizumi, Hiroaki Shirasaka

"The new type of nano-porous silica particle was considered to be constructed by the spinodal decomposition-type process which was found to have narrower pores than those of conventional porous silica prepared from boron silicate or ""Shirasu"" balloon. Nano-porous silica particles were fabricated by the calcination of silica gel mixed with well-dispersed complex salts composed of phosphorous and molybdenum compounds. Both silica and inorganic salts were not perfectly dissolved in the suspension solution. After removing of the water, the silica-inorganic salts complex was volatized and successively calcinated at a temperature ranging from 650 °C to 800 °C. Then, the inorganic salts were removed by dissolving in hot water. Other inorganic salts such as potassium halides were also found to be effective as a pore-size controller.IntroductionControl of structure has an important role in the field of industry as well as in the separation and purification technology for metals and organic syntheses. Many studies on the control of material structures have been reported regarding porous materials with pores ranging from nanometer to micrometer scale. 1 ) One example is zeolite as a naturally yielded porous inorganic material. Various types of synthetic zeolites have been studied as ""molecular sieve"" materials with ordinary pore-size of less than one nanometer. In 1992, crystalline meso-porous material with a large surface area named MCM-41 was synthesized through the use of template synthesis. 2) In direct relation to our study, amorphous borate glass having 4 to 100 nm of fine pores known as Corning glass 3l or SiO2-Al2OrB2O 3-CaO porous glass having large pore dispersity ranging from 4 to 10,000 nm have been reported. 4 ) S) 6 ) Some examples of several reported studies are as follows: phase-separated porous glass consisting of B2OrAl2O3-ZrO2-RO-R2O complex oxide 7 ) glass with finer pore induced from hydrolysis of silane alkoxide, porous material attained by condensation polymerization through the use of sol-gel process 8), alumina meso-porous material 9 ) 10), silica-zirconia material 11), carbon porous material 12), etc.."

Jan 1, 2000

By T. Shibasaki

There is a strong demand in the photo industry to the higher quality of refined silver. Osaka Refinery produces about 27 mtpm of refined silver mainly from copper refinery slimes. Product quality is attained by controlling the impurity level in electrolyte. Copper is cemented with silver oxide and palladium is precipitated by a chelating agent. Both processes were operated previously in batchwise for treatment of bled out electrolyte, Recently these processes have been improved and made continuous to cope with the increased impurity.load. As a result the grade of fine silver has been maintained steadily at Pd < 3 ppm and Cu < 5 ppm.

Jan 1, 1989

By Patricio Barrios

In February 1996, ATLANTIC, COPPER completed the construction of a Project for Expansion and Environmental Improvements in its Smelter and Electrolytic Refinery located in Huelva. Following the expansion, the new operating concept is based on the simultaneous blowing of two converters, while increasing throughput in the Flash Furnace up to the level required to deliver matte to both converters. While the production level planned with the Project.(270,000 MTPY of copper from concentrates) was reached the following June, work since then has been carried out to optimize the new equipment .and to develop a new operating shedule. This paper describes operational experiences from the start up of the Expansion Project, difficulties encountered and operating improvements introduced, which have allow an increase of production levels up to 300,000 MTPY of copper.

Jan 1, 1998

By T. S. Bannos

Section 1417 of the Safe Drinking Water Act Amendments enacted by the O.S. Congress prohibits the use of lead containing solders for potable water systems in new construction or when making repairs. The legislature defines "lead-free" solder as containing less than 0.2% lead. In the development of a new solder it was recognized in addition to the lead free requirement, the alloy should perform as well as the popular 50/50 tin lead solder, both in application and properties. Another objective was to have only nontoxic elements. This led to the development of a 4.0% copper, 0.5% silver and 95.5% tin solder. Review of the merits of other alloy systems and the development of the physical properties along with test data are presented for the lead free tin. rich alloy.

Jan 1, 1990

By Yasuhiro Konishi, Kazunari Mizoe

"This paper describes a new processing of ultrafine, magnetic ferrites from sulfuric acid pickling solution in steel industry. In the ferrite processing, the iron (II) in the pickling solution was first oxidized to iron (III) by using the acidophilic thennophile Acidianus brierleyi. The bio-oxidized pickling solution was treated with solvent extraction to separate the iron (III) into the organic solution of tertiary aliphatic monocarboxylic acid. After that, the carboxylate solutions of iron (III) and other metal (cobalt) were hydrolyzed and precipitated ultrafine particles of crystalline ferrites at l90°C and l. 3 MPa for 20 min.IntroductionHot-rolled steel sheet has always a layer of oxides on its surface. The oxide layer arises as scale in hot rolling processes in steel industry, and the scale consists of the three iron oxides such as hematite Fez03, magnetite Fep4, and wustite FeO. Pickling removes chemically the scale layer that adheres to the steel surface. For normal steels, pickling is carried out in 15-20% hydrochloric acid at 60-70°C or in 20-25% sulfuric acid at 95-100°C. When steel is pickled with sulfuric acid, the scale oxides dissolve to give iron (II) sulfate.Spent pickling solutions are hazardous wastes containing a large amount of dissolved iron (II) and sulfuric acid, e.g., about 40 kg/m3 of dissolved iron (II) at pH 0. In typical commercial processes, spent pickling solution is usually cooled evaporatively to 5°C, and then to 0°C to crystallize iron (II) sulfate as its heptahydrate. After the crystallization operation, the sulfuric acid can be reused in the pickling operation.In this paper we describes a new processing of ultrafine, magnetic ferrite from sulfuric acid pickling solution, in order to recover dissolved iron (II) in the form of a valuable product. In the ferrite processing, the iron (III) was first supplied by the microbial oxidation of iron (II) in the pickling solution, and then the biooxidized pickling solution was treated with solvent extraction to separate the iron (III) into the organic carboxylate solution. After that, the carboxylate solutions of iron (III) and other metal (cobalt) were precipitated crystalline ferrites under hydrothermal conditions."

Jan 1, 2000

By I. M. S. Moraes

Caraiba Metais has a plant for the purification and the cristallization of the crude nickel sulfate removed from its copper electrolyte purification system. In November 1994, an interdepartmental group was formed to study the Q.F.D. method, through its application on the improvement of the quality of the nickel sulphate hexahydrate. The team, formed with representatives of the following areas : production, technology, marketing, sales, maintenance, laboratory and TQC office, had also the task of checking the applicability of the method to other products of the comp any. This paper describes the main steps such as the survey of customer&apos;s demands, the preparation o1 the quality matrix, stablishing the planned quality matrix, the planned and the designed quality, and the consequent identification of the engineering bottlenecks. It is also shown how these bottllenecks were studied and solved. The application of the method allowed the team to identify means of increasing the production capacity by 40%, to improve the intrinsic quality of the product (including packaging), and to increase the reliability of the process.

Jan 1, 1997

By Mike Adams

A comprehensive pre-feasibility study has been conducted by Companhia Vale do Rio Doce CVRD) for Niquel do Vermelho nickel laterite deposit. Within this study, five integrated flowsheet options were evaluated via batch and pilot campaigns at Lakefield Oretest, over an intensive six-month period from receipt of ore to final reporting. Key technical objectives set by the client included demonstrating the technical viability of the beneficiation of several ore types, processing through integrated pressure acid leach/mixed hydroxide precipitation (PALIMI-IP) and mixed sulfide precipitation (PALIMSP) circuits, and the treatment of barren liquors to meet stringent environmental requirements. Refining of the MHP was by ammonia re-leach and solvent extraction (SX) to produce LME-grade nickel cathodes, NiCO3, NiO and CoS. LME grade nickel and cobalt was also produced by oxidation of the MSP and hydrogen reduction on the leachate. The database and data acquisition system, along with web-based reporting, enabled rapid turnaround on both daily and more comprehensive run reports, making it possible for speedy and confident decisions on operating conditions of the complex flowsheets. The high value of developing such data is emphasized and discussed as pivotal in the successful progression of laterite projects through to sustainable commercial viability. Keywords: Flowsheet, CVRD, Nickel, Piloting, Pressure, Leach, Refining.

Jan 1, 2004

By M. I. Novgorodova

Most of the gold in the earth&apos;s crust occurs as finely-dispersed gold and accounts for much of the gold lost in extraction processes and during exploration for gold. The Compositions, sizes, and morphology of fine gold particles (0.01 to 10 ~m in diameter) were studied with high resolution electron microscopy coupled with electron microprobe and microdiffraction devices, using colloidal carbon replicas. Correlations were made between fine gold, mineral associations and ore genesis. The results provide qualitative information on the proportions of finely dispersed, invisible and visible gold distribution in ores. Such knowledge is fundamental when planning an optimum technological recovery process.

Jan 1, 1991

By John J. Friel

Digital imaging systems are particularly useful in microscopy, because they make it possible to extract information not readily accessible by manual methods and to display that information clearly. Computer-aided imaging systems analyze, process and compare images, and of these, image analysis is most useful in materials science. Image analysis quantifies the microstructure by making measurements on the entire field or by measuring the size and shape of features individually. Even true surface area can be calculated. Modem image analyzers make thousands of measurements in seconds, leaving the investigator to interpret the data and relate them to process and material properties. Image processing, which may be necessary to prepare an image for analysis, includes everything from simple contrast transforms and kernel filters to complicated processes such as grain boundary reconstruction using artificial intelligence. An example of image comparison is point-by-point screening of X-ray maps of different elements to extract phases. In all of these operations, the computer makes a large number of measurements in seconds and returns information that could not be realistically obtained by manual methods.

Jan 1, 1992

By W. F. Ranson, R. C. Progelhof

"I. THE PROBLEM: MANUFACTURING PRODUCTIVITYThe 1985 President's Commission [I] on Industrial Competitiveness found compelling evidence of the declining economic position of the United States in world markets. The annual rate of increase in the United States productivity is approximately one-seventh that of our major trading partners over the last decade: profit levels in manufacturing investments are below those of the mid-1960's; an increasingly negative trade balance since 1971; and a sharp decline in the United States share of world trade in manufactured goods for more than two decades. A particularly dramatic example of the shifting economic balance is the fact that Japanese productivity growth has been five times greater than that of this country since 1960. In face, Japan's productivity now exceeds that of the United States in such critical industries as steel, transportation equipment, electronics and electrical machinery.American employees have experienced the competitive consequences of this nation's lagging industrial performance. Between 1980 and 1984 alone, the population of non-farm employees engaged in manufacturing dropped from 22.4% to 20.6%. This reduction in manufacturing must be arrested.Commissions RecommendationsThe comprehensive set of recommendations offered by the President's Commission recognized the nation's ""key competitive advantages"", technology and human resources, and calls for their strengthening. Particular emphasis is placed on manufacturing technology and the fact that this country does not translate research into new technologies rapidly and fully.""Perhaps the most glaring deficiency in America's technological capabilities has been our failure to devote enough attention to manufacturing or 'process' technology. It does us little good to design state-of-the-art products if within a short time our foreign competitors can manufacture them more cheaply. The United States has failed to apply its own technologies to manufacturing. Robotics automation and statistical quality control were all first developed in the United States but in recent years they have been more effectively applied elsewhere""."

Jan 1, 1988

By T. A. Larssen

The efficiency in production of manganese ferroalloys is dependent on the gaseous reduction of the higher manganese oxides in the ores used as raw materials. The materials, descending in the furnace, will meet the furnace gas that contains significant amounts of CO(g) and reduce in subsequent steps, the last step being reduction of Mn3O4 to MnO. This step may to varying extent occur at temperatures exceeding 800 °C, i.e. in the active region of the Boudouard reaction. The gas reduction of Assmang and Comilog manganese ores were investigated in CO-CO2-atmosphere at temperatures up to 1000 °C. It was seen that decreasing ore size correlates to a lower reduction temperature and increasing reduction rate. Similar effect was observed with increasing CO-content in the gas atmosphere. Further, it was found that Comilog ore obtained a complete prereduction at 600 °C, whereas reduction of Assmang ore was not complete at 800 °C for the majority of the experiments.

By Saskia Duyvesteyn

Ion flotation is a technique applicable to the removal of metal ions from dilute solutions, using ionic surfactants.- While there are a number of physical and chemical parameters that influence the ion flotation process, this paper focuses on two of the important chemical ones, namely frother concentration and ionic strength. The effect of several frothers, including ethanol, iso-propanol and MIBC at concentrations ranging from 0% to 0.4%, was studied for the model Cd-dodecylsulfate and Cu-dodecylsulfate systems. The ionic strength, as well as the effect of monovalent and multivalent counter ions, was also studied in the range of 1@3 - 1 M, at constant pH. The results are discussed in terms of applicability to a range of effluents from minerals and materials processing operations.

Jan 1, 1994