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By T. Maruyama

The Tamano Smelter of Hibi Kyodo Smelting CO. ,Ltd. went into operation in 1972. The Flash Smelting Furnace that was originally adapted was equipped with electrodes that were attached to the settler substitute of the slag cleaning furnace. Later the development of our own original coke combustion technology was promoted and a new Tamano Type Flash Smelting Furnace (T-FSF), without electrodes, was put into operation in 1988. The technology of coke combustion and combustion the burner have continued to improve. As a result the copper losses in the slag have been reduced as well as a stable operation has been achieved. Furthermore, this has been accomplished while increasing the concentration feed and the matte grade The current objective is to continue to strive for high matte grade operation and to raise production efficiency while paying attention to the important subject of copper losses in the slag. In this report, the data related to the copper loss in the slag reduction are presented along with the influence of the thickness, settling time and coke. The recent operation conditions of the T- FSF are also presented.

Jan 1, 2003

By Grant Wallace, Rod James, Larry Twidwell, Ed Rosenberg, Courtney Young, Sean Dudley, Hsing-Hsin Huang, William Gleason, Jerome Downey

The use of applied chemistry in the production and optimization of leach solutions from Rare Earth Element (REE) ores and concentrates is being investigated. Ore and concentrate samples were characterized using scanning electron microscopy/mineral liberation analysis (SEM/MLA), X-ray diffraction (XRD), and Atomic emission inductively-coupled plasma spectroscopy (ICPAES). Multiple leach tests were performed to analyze the effects of temperature, residence time, and reagent concentration on the leaching of REEs. Analysis of leach solutions was carried out using ICP-AES. Modeling and statistical analysis of extraction behavior was carried out using DesignExpert 9. Modeling data for cerium extraction indicates that extraction is greatly influenced by temperature and reagent concentration, while leaching time plays a much less important role. Experimental design techniques are being utilized to optimize REE recovery. Results, conclusions, and directions for future studies will also be discussed.

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 W. Drummond

The cooling of smelter gases by air dilution, adiabatic evaporative cooling and indirect heat exchange is discussed with reference to the ,process, to the subsequent cleaning of the gas and to the use of the heat extracted from the gas. The method of reducing the effect of acidic ,sulphide formation on the corrosive properties of the gas and the dust and the development of surface cleaning mechanisms are discussed. The development of indirect recuperators using air, water or steam cooling, made 'possible by the control of surface fouling is traced. The application of the modern Waste Heat Boiler to the new sulphide smelting processes is discussed with respect to the natural and forced circulation concepts. Case histories are presented to illustrate mistakes made with respect to designs produced without recourse to sensitivity analysis and without an appreciation of "worst process conditions".

Jan 1, 1992

By J. K. Brimacombe, I. V. Samarasekera, B. G. Thomas

"Mathematical models have been developed for the processing of static cast steel ingots and are app1ied to investigate the mechanisms for the formation of panel cracks. Panel cracking is an intermittent but persistent defect that causes affected steel ingots to be scrapped. A two-dimensional, finite-element, heat-transfer model was formulated and employed to calculate the temperature distribution in both large and small steel ingots during the various processing stages from initial casting to the start of rolling, including solidification, cooling in the mold and in air, reheating in the soaking pit, and subsequent air cooling. The stress state in the ingot arising from the calculated temperature variations was then determined. This involved the development of a transient, elasto-visco-plastic, finite element, thermal stress model, including the effects of phase transformation volume changes and kinetics creep, and temperature-dependent, mechanical properties. The results of the mathematical model predictions of temperature and stress were then used to determine the mechanisms and to suggest solutions for two different types of panel crack formation. Mid-face panel cracks apparently form during air cooling when the mid-face surface temperature is between the Arl and 500~C. Off-corner panel cracks appear to initiate internally during the early stages of reheating but do not propagate to the surface until much later. IntroductionPanel crack formation in static-cast steel ingots is a defect that has been plaguing the steel industry for several decades. Although the problem is intermittent, it is also serious since affected ingots must be scrapped. Panel cracks are manifested as two distinct types of cracking problems. ""Mid-face"" panel cracks are found exclusively in small, 2 to 6 ton, medium carbon steel (0.3 to 0.7% C) ingots and usually exhibit a single, continuous, longitudinal crack down the center of one of the ingot faces as shown in Fig. l (l). ""Off-corner"" panel cracks often form roughly oval, discontinuous crack patterns on the wide faces of large, 20 to 30 ton ingots as seen in Fig. 2 (2). They affect only low carbon steels (0. l to 0.2% C) with high manganese content. Both defects affect only aluminum-treated steels and are caused by a combination of intermediate temperature ductility loss involving aluminum-nitride precipitation and thermal stress generation. The ductility problem has received a good deal of attention which was the subject of a recent review (3). The present study was undertaken to investigate the thermal stress aspects of the problem through the development of mathematical models of heat transfer and stress generation in static-cast steel ingots. The ultimate objective was to elucidate the mechanisms of formation for both types of panel crack and to evaluate possible solutions to the problem."

Jan 1, 1986

By Jiangtao Li, Zhongwei Zhao, Xingyu Chen, Xuheng Liu

The method of ultrasonic-assisted leaching was used to extract vanadium from the stone coal, with alkali as leaching reagent. The effects of ultrasonic power, concentration of alkali, reaction temperature, liquid-solid ratio and reaction time were investigated, respectively. The optimal ultrasonic leaching condition for vanadium extraction is as follows: ultrasonic power 230W, concentration of alkali 5%, liquid-solid ratio 3:1, reaction temperature 90℃ and reaction time 1h. The leaching rate of vanadium reaches 76.4% under the optimal condition, which is 12.2% higher than that of non-ultrasonic leaching. The reason on enhancing the leaching rate of vanadium by ultrasonic leaching was discussed. It is indicated that the ultrasonic cavitation can increase the surface area of mineral, which is beneficial to facilitate the reaction rate. Keywords: stone coal; vanadium; alkaline leaching; ultrasonic

Jan 1, 2014

By Yoshisada Michiura, Junko Umeda, Katsuyoshi Kondoh

Rice husks or straws, one of the main agricultural wastes in South-east Asia, have a large possibility to be employed as usefully renewable resources to produce energy and high-purity silica (SiO2), because they consist of about 70% organics such as cellulose or hemi-cellulose, and 20% amorphous SiO2. The former is utilized as bio-mass energy; for example, thermal or electric energy, and bio-mass ethanol. High-purity silica can be used as raw materials in the industrial uses. It would be possible to extract silica elements from rice husks and straws by burning them in air because their main contents are organics. In the previous studies, a strong acid leaching treatment on rice husks before burning was carried out by using H2SO4, HCl and HNO3 to prepare high-purity silica materials. This was available to accelerate the hydrolysis of celluloses and hemicelluloses contained in rice husks, and remove the above metallic impurities. A strong acid leaching treatment, however, is significantly hazardous to environment and human life, and causes an increase of the process cost. In this study, the environmentally benign, harmless to human and economically effective process to produce high-purity amorphous SiO2 materials from rice husks has been established without using strong acids. From a viewpoint of the harmless influence on human body, the carboxylic acids were used in the leaching treatment on rice husks. TG-DTA measurement and GCMS analysis indicated that the leaching was effective for the hydrolysis of celluloses and hemicelluloses contained in rice husks at 473K~873K, which produced the same results in using the conventional sulfuric acid. The metallic impurities could be also removed from the husks via a chelate reaction between carboxyl groups (-COOH) and the metal elements. In particular, it was clarified that cadmium (Cd) were completely removed from rice straws by this reaction. Concerning the burning conditions of rice husks after the acid leaching, it was necessary to supply a suitable amount of air to completely combust organics; for example it required air supplement of 50 ml/min. or more. The burning temperature should be less than 1273K to obtain amorphous structured silica. High-purity amorphous silica materials with 99% or more were prepared from rich husks by applying the citric acid leaching treatment and burning process at 1073K in air.

Jan 1, 2008

By Walter Curlook

An improved process of hydrometallurgical treatment of laterite ores of the limonitic type for the recovery of nickel and cobalt using sulphuric acid has been developed and patented [I]. The major improvement is brought about by recycling a significant portion of the "mother liquor" emanating from the pressure leaching reaction back to the feed preparation stage thereby substituting for all or at least a major proportion of the fresh water that must be added. The amount of process effluent waters is correspondingly reduced. Concomitantly with the major savings in fresh water requirements, a degree of reduction in new sulphuric acid requirements is effected, along with a savings in limestone and lime required for subsequent neutralizations. Keywords: Acid pressure leaching; Nickel laterites

Jan 1, 2004

By K. Fagerlund

In this work, the rate of dissolution, melting behaviour and phase separation of silica flux with molten slag and matte were investigated. Mutual dissolution between high-grade matte and silica was chemically determined. Silica dissolution rates ,in various iron silicate slags was determined using the rotating rod method. The reaction and separation phenomena of slightly oxidised chalcopyrite samples and cuprous sulphide-magnetite mixtures with silica sand were examined all about 1350°C. The samples were water quenched, and polished specimens were studied and analysed using a light optical microscope ,and a scanning electron microscope with energy dispersive spectrometer. The silica dissolution rate in slag was found to increase with decreasing silica content and increasing ferric iron content. The reaction rate of silica sand' with matte was found to increase with increasing oxidation degree and magnetite content of matte:

Jan 1, 1998

By Hang Goo Kim

A mathematical analysis based on equilibrium modeling has been developed to describe the distribution behavior of minor elements such as Pb, Zn, Bi, Sb, and As among gas, slag and recovered copper phases during the reduction of copper oxide in slag cleaning with CO gas. The results show that large fractions of the impurities transferred to slag during smelting or converting are recycled to the recovered copper metal. It is also shown that there is a limit to the recovery of copper from slag because iron oxides are also reduced to form a copper-iron alloy at low oxygen potentials. The effects of various operating parameters such as temperature, the activity of FeO, the initial amounts of the elements in the slag and CO content in process gas, on the behavior of these minor elements are discussed. The predicted results were compared with the results of a pilot plant operation in which pulverized coal was used as a reductant. Consistent trends between the two cases were obtained.

Jan 1, 1992

By Xiaojie Gao, Shufeng Yang, Jingshe Li, Chengsong Liu

In the blast furnace process, the dust entrained in the blast furnace gas enters into the down-comer, flows through the gravity dust separator (to eliminate coarse particles) and then is collected in a bag-house. The powder collected by the baghouse is called bag dust, while both fractions are called blast furnace dust whose main components are C and Fe. The dust also contains small amounts of nonferrous metals such as Zn and Pb, which have some value. Also, due to the small particle size and low density the dust is easily suspended in air and so can endanger human health. Therefore it is necessary to develop a process to both treat the dust to recover the metal values and to dispose of the residue – preferably by recycling to the blast furnace itself via the sinter strand. These objectives will result in good economic, environmental and social benefits [1].

Jan 1, 2014

By Larry B. Fiske

Elimination of dust and processing of fines for both thermal and metallurgical coals is addressed. The efficiency of treatment with lignosulfonates compares favorably to oil in thermal coal. Effect of treatment with various lignosulfonates upon cokability of metallurgical coal was determined by Free Swelling Index, Gieseler Plasticity and Arnu Dilatation.

Jan 1, 1992

By Keuncheol Choi, Yonghack Lee

"The new lead smelter based on the QSL technology was started operation from May 1992 at Onsan Refinery of Korea Zinc Co., Ltd. The smelter is designed to treat not only various types of lead concentrate but also secondary materials coming from the zinc plant without special pretreatment.Shortly after the start-up of the operation, it has demonstrated that the smelter have a capability to treat wide range of raw materials. Continuous modifications and improvements of the plant are still under way to increase the feed rate and also the ratio of secondary materials to the feed.In this paper, the operating experience and results of QSL smelter, especially the injection of gases and coal to the melt, will be presented with major operation parameters and data.INTRODUCTIONThe QSL lead smelter based on new injection technology was commissioned at the Korea Zinc's Onsan plant from May of 1992. After starting the operation, the QSL lead smelter faced various kinds of mechanical and metallurgical troubles. However, these were gradually worked out by the continuous improvements and efforts.At present, the QSL lead smelter is operated stably at the total feed rate of 57 tonnes per hour with an increased amount of secondary materials."

Jan 1, 1996

By Z. Zak Fang, P. Fan, S. Middlemas

"Titanium dioxide (T1O2) has been widely used as pigment in paints, paper and cosmetic products, as well as high-tech applications such as PV Cells, semiconductors, biomedical devices and air purification. T1O2 pigment is primarily produced by the high temperature chloride process, resulting in considerable CO2 emissions. A novel hydrometallurgical process for making T1O2 pigment without direct CO2 emission is investigated. The new method promises to eliminate direct CO2 emissions, consume significantly less energy, and produce minimal environmental waste. The novel process involves molten salt roasting of titania slag, with subsequent washing, leaching, solution purification, hydrolysis, calcination and post-treatment stages, resulting in high-purity anatase or rutile pigments while realizing significantly reduced environmental impacts. Pigment whiteness is critically sensitive to trace amounts of discoloring impurities such as iron and chromium. Several methods for reducing the levels of these impurities are investigated. Energy consumption and emission models are also developed.IntroductionTitanium dioxide (T1O2) is one of the most commonly used minerals in the chemical manufacturing industry. It has been commercially processed since the early 1900's, and has a wide variety of applications. Pigment is used in paints [1], plastics and paper [2], sunscreen [3], cosmetics and even as a food additive [4]. T1O2 has also been used in photovoltaic cells [5], biomedical devices [6], and in air purification [7]. T1O2 pigment has a refractive index of 2.7, which imparts a high level of opacity (and hence whiteness) to whatever material it is added [8]."

Jan 1, 2012

By C. M. F. Viera

In this work the properties of a clayey ceramic incorporated, up to 10 wt.%, with three types of wastes from a water treatment plant was evaluated. To determine the physical and mechanical properties such as linear shrinkage, water absorption and diametrical compression, specimens were prepared by 18 MPa uniaxial pressure and then fired in laboratory furnace at 700oC. The results indicated that the wastes incorporation changed the properties of the clayey ceramic. From the results it was found it possible to recycle these wastes into clayey ceramic in low amounts to avoid deleterious effect on the quality of the fired product.

Jan 1, 2008

By Seong-Jong Kim

The formation behavior and corrosion characteristics of anodic oxide films on pure Mg and Mg-AI alloys were investigated focusing on the effects of anodizing potential, Al content, temperature and NaOH concentration. Pure Mg and Mg-AI alloys were anodized for 10 min at 3, 10, 40, and 80 V in NaOH solutions. Mg(OH)2 was generated by an active dissolution reaction at the surface of the specimen and the product was affected by temperature while MgO generation increased with NaOH concentration. Moreover, the current density after anodizing for 10 min at a constant potential decreased with increasing AI content in Mg-AI alloys,

Jan 1, 2003

By Guo Gongyi

An extraction chromatography by which 99.99 % pure scandium oxide can be prepared from the starting materiel containing about 70% scandium oxide has been developed by taking advantage of some peculiar properties of the complex chemistry and extraction chemistry of scandium. The purification of scandium was performed at room temperature with relatively fast rates in two chromatographic columns. The preliminary separation of scandium from impurities was done by extraction chromatography using tri-butyl phosphate as the stationery phase in the presence of citric acid, and the nearly complete separation in the presence of perchloric acid. The scandium recovery was greater than 90 %.

Jan 1, 1989

By Shiwei Sun, Hongxu Li, Xiangxin Hao, Xie Yang

"Environmental impact assessment of copper metallurgical processes will soon become a compulsory activity in the future. The goal of this work is to analyses the copper metallurgical processes including pyro-metallurgy and hydrometallurgy based on the life cycle assessment method implemented in GaBi software. The evaluation indicators such as global warming potential (GWP), acidification potential (AP), photochemical ozone creation potential (POCP) and human toxic potential (HTP) are taken into account. The results show that the major environmental impact phase in pyro-metallurgy derives from beneficiation because of the largest material and energy consumption. It is also shown that copper hydrometallurgy has significantly lower environmental impact than pyro-metallurgy. Based on the evaluation results, some corresponding optimization methods are recommended to reduce environmental impact.IntroductionCopper is an important metal in modem society due to its wide variety of uses, including electrical wiring, heat exchangers, piping and roof construction and increasingly consumer electronics. Demand for copper has increased dramatically over the past decades, driving production rates almost exponentially. Annual production of copper was estimated to be 20 million tonnes in 2012 with Chinese production at about 6.06 million ton in 2012P1. The production process of copper has environment impacts that often go unnoticed by the producer. Higher production, coupled with declining ore grades, is placing increasing pressure on the natural environment.Sound environmental management helps producers improve their manufacturing technique. LCA is a well-established tool for assessing environmental impact potential and can be readily adapted to map impact potential over time, which can be used to quantify the environment impacts of a product or a process [21. This is achieved by creating an inventory of all the energy and material flows used in the process's life cycle. The results of an LCA can be used to improve the operation of a process so that they have less impact on the environment."

Jan 1, 2014

By A. V. Kuznetsov, R. I. Kamkin, V. M. Paretskiy, A. Y. Mamaev, V. P. Bystrov, A. S. Vernigora

"Vanukov furnace technology is an efficient, proven pyrometallurgical injection technology, used extensively in Russia and Kazakhstan for a number of different applications. The technology was most widely adopted for processing copper sulfide concentrates for matte in smelters in Norilsk, Revda (Russia) and Balkhash (Kazakhstan). The following applications also were developed and tested at industrial scale: treatment of sulfide lead and lead-zinc concentrates, laterite nickel ore, production of cast iron, treatment of antimony gold-containing ores, and municipal solid waste. In this paper, current experience of Vanukov furnace application to these technologies is described with a number of general development trends and new areas of application.IntroductionAt the present time, the Vanukov process, developed at the Moscow State Institute of Steel and Alloys at the Department of metallurgy of non-ferrous, rare and noble metals with collaboration with other research organizations, is a highly efficient technological solution for processing different kinds of raw materials. The process was invented by Professor Andrey Vladimirovich Vanukov, whose research work began in 1949. From 1956 to 1975 test runs of the technology were carried out at the smelters in Norilsk and Balkhash. In 1976 a pilot Vanukov furnace was built in Ryazan. Furnace designs was modified to suit the various test programs. A major objective of each experiment was the determination of optimal working conditions for processing different types of raw materials such as copper, copper-nickel, copper-zinc, lead or pyrite concentrates, and materials containing secondary lead and zinc. After the death of Andrey Vladimirovich Vanukov in 1986, this technology and furnaces based on the technology were named after him: “Vanukov process” and “Vanukov furnace”. Today, the following furnaces based on Vanukov technology are either working or were tested at semi-industrial scale: three in Norilsk, two in Revda (Russia) and two in Balkhash (Kazakhstan) for treatment of copper sulfide concentrates for matte, one in Orsk (Russia) for processing laterite nickel ore, one in the Buruktal plant (Russia) for antimony gold-containing ores for antimony oxide sublimates and gold-containing metallic antimony, and one in China for processing sulfide lead and lead-zinc concentrates for production of black lead and zinc-containing sublimates."

Jan 1, 2011

By Hongmin Zhu, Kai Huang, Shuqiang Jiao

"Garlic peel was used as the raw material to synthesize the biosorbent for the selective recovery of precious metals from the acid chloride solution. Garlic peel is rich in carboxyl-, amino- and thiol-groups, has the potential of exhibiting high affinity to Au(III) when appropriate chemical modification process was employed. Here in the present study, the biosorbent was prepared by cross-linking garlic peel particles with concentrated sulfuric acid. Adsorption tests for mixing different metal ions such as Au(III), Fe(III), Cu(II), Ni(II) and Zn(II) from various concentrations of hydrochloric acid media indicated that Au(III) was selectively adsorbed on the cross-linked garlic peel gel over the other coexisting base metal ions investigated. The crosslinking mechanism and selective adsorption of Au(III) were also investigated briefly.IntroductionPrecious metals are quite popularly applied in the modern industries such as jewelry, electronics and electrical devices, catalysts in chemical industry, etc. While their high values, limited deposit and quite large demand in industry makes its recovery from the industrial wastes, typically e-wastes, quite necessary. Actually, many techniques have been developed to recycle and recover the precious metals from various industrial wastes effectively in last decades, but the cleaning and ecofriendly processes are still seriously scarce [1]. Taking into account of the typical recovery processes using cyanide lixiviant in the alkaline media, or aqua regia, followed by the further recovery process using activated carbon adsorption or cementation with zinc, iron or aluminum plate or powder, though they both are quite effective recovery processes, if considering the special requirements on safety and ecofriendliness for the modern hydrometallurgical processes, various improved or novel extraction processes are greatly demanded [2]. Recently, the biosorption technology applied to the recover precious metals in the hydrometallurgical process has become a concern [3,4]. Inoue’s research group made great progress in the recovery of precious metals such as gold, palladium and platinum from the e-wastes such as spent mobile phone by using biosorption from the hydrochloric acid media [5,6]. This new hydrometallurgical process exhibits the prominent advantages of being cost-effective for its short process, easy operation and near-zero emission. In the above recycling process for e-wastes treatment, the preparation of biosorbents is the key and backbone of the whole recovery process. For this purpose, they developed a series of suitable sorbents for precious metals recovery by using the tanning-based or cellulose-based biomass such as persimmon peel, grape peel, orange juicing residue, waste cotton, waste paper through the crosslinking process with concentrated sulfuric acid and relative chemical modification processes [7-10]. In the present study, we also applied this technique to prepare the biosorbent of precious metal uptaking by using garlic peels as the raw materials, and investigated the adsorption properties of such-obtained gel in the hydrochloric acid media."

Jan 1, 2012