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By Liyuan Chai, Qin Liu, Bing Peng, Jia Wang, Qiang Zhang

"Electrolytic Manganese Residue (EMR) was used as the main material to prepare cementing material activator for the utilization of the residue from electrolytic manganese dioxide (EMD) or electrolytic metallic manganese (EMM) production. The effects of chemical activation, thermal activation and mechanical activation on retarding activity and excitation activity of EMR were investigated according to the setting time and activity index of EMR-slag cementing material. The results showed that the EMR exhibited good activating performance after being ball-milled for 18 min and then treated for 1-2 hours at temperature range of 350-450 ?. The optimal properties of cementing material activator were achieved at the weight percent ratio 30 : 3 : 5 of EMR/Ca(OH)2/cement clinker.IntroductionMany hazardous industrial solid wastes such as blast furnace slag, fly ash, steelmaking slag, chromic slag and electrolytic manganese residue [1] are generated n China and their amounts increases every year. The accumulation of the solid wastes during past years is very huge and they could be hardly recycled effectively as a sustainable resource. 2.35 billion tons of industrial solid wastes have been produced up to now [2]. It is estimated that they would exceed 3.3 billion tons by the end of 2015 [3]. On the other hand, the quick development of Chinese infrastructural construction needs more cementing materials. The production of traditional building materials consumes lots of natural resource such as clay and limestone and discharges at least 1 ton CO2 and other pollutants per ton clinker [4]. Therefore, it is necessary to develop new types of cementing materials instead of clinker [5,6]."

Jan 1, 2012

By P. Balachandran

The paper outlines the existing facilities and working practices at the Khetri electro-refinery of Hindustan Copper Limited. Plans have been drawn up to mechanize some key operations to improve the quality of cathodes and the working environment as well as economize the refinery operations. The economic analysis for determining various optimum operational parameters under conditions existing in India have also been outlined. The impact of capacity utilization and mechanization under different sets of conditions on operational costs have been highlighted.

Jan 1, 1987

By P. S. Seryogin

R & D works supported by industrial-scale tests, which were carried out by joint efforts of the OAO Gipronickel Institute and MMC ?Kola? engineers, have accomplished with the production of 90?95% metallized nickel powder in tube furnaces (NPTF), with its ?active fraction? (AF) to be further used for decopperization of nickel electrolyte by cementation. Consistently positive results obtained in the course of the lab and industrial experiments have allowed the Severonickel Combine management to effectively replace all activated nickel powder (ANP), which was then employed for cementation, with the AF, having activity over 80%, and eventually shut down the entire operation of gaseous reduction. Ever since the developed technology has been implemented, its annual economic effect exceeds 2 ml. dollars.

Jan 1, 2006

By N. J. Themelis

In the last two decades, the Outokumpu flash smelting process has become the dominant new technology for copper smelting and has? also been applied to the smelting of other metal sulfides. The application of oxygen enrichment and improvements in concentrate burner and furnace design have resulted in ever increasing smelting rates per unit volume of the reaction shaft. This paper examines the. rate phenomena taking place in the reaction shaft of the Outokumpu furnace and compares information obtained from a mathematical model of heat and mass transfer rates to results obtained in pi1ot tests conducted at Pori, Finland, and to actual performance of a number of flash smelters around the world. 2?

Jan 1, 1985

By S. Katz, V. Stanek, K. L. Moore, E. D. Larsen, D. E. Clark, P. E. King

"Cupola melting is a complex physical and chemical process having a number of nonlinearities which make conventional process control difficult. In addition, sensors for both inputs and outputs of interest to the foundry operator are often difficult or impractical to apply in a production situation. The present work is an effort to control the process using both intelligent and conventional control techniques as appropriate. Neural networks are used as an inverse process model in a cascade, feedforward controller in conjunction with a finite difference model of the cupola. A separate implementation of the neural net serves as a stand-alone visualization tool; it can operate on a laptop computer and is a useful tool for the cupola operator. IntroductionThe goal of the present work is to develop a controller to improve the efficiency of cupola melting. Although cupola melting as a process has a long history, automatic control has been elusive because the process has been poorly understood. The purpose of this four-year program, which has been underway for about six months, is to develop a controller for the cupola process using intelligent and conventional control methods.The Cupola ProcessThe cupola furnace [1,2] is one of the oldest processes for making cast iron, and is still the dominant method. It takes the form of a water-cooled vertical cylinder, as large as 4 m in diameter and 20 m tall. The charge consists of scrap metal, alloying ingredients, limestone, and coke, which serves as fuel; it is composed by weight and fed through doors near the top of the cupola. Air, usually heated and often enriched with oxygen, is blown in near the bottom through tuyeres extending a short distance into the interior of the cupola. As the coke is consumed, the charge drops and melts. A continuous flow of iron emerges from the bottom of the furnace, at rates as high as 100 tons per hour, and. is transferred to casting lines in the foundry. The exhaust gases are drawn from the top of the cupola, where they are processed to meet pollution standards."

Jan 1, 1994

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 Kumar Ganesan

Elevated mercury levels are expected in aged gold mine tailings due to residual mercury from the amalgamation process, The fate of mercury in tailings is not well understood, Its potential health risk depends mainly on the degree to which mercury is mobile in soil. Mercury is re-moved from soil by evaporation, plant uptake, microbial activities, leaching, and other physico-chemical processes. In this research the amount of mercury lost by evaporation was evaluated. Several aged gold mine tailings in Montana were sampled for total mercury and its flux into the atmosphere. Mercury levels in tailings were higher than the general background levels in most sites. The mercury levels in some cases were as high as 10,000 ug/g. The field measurements using flux chambers indicated a wide range of mercury flux from aged gold mine tailings. The mercury flux ranged from 0-11,000 ng/m2/hr. The mercury loss by evaporation helps rid the soil of mercury but the mercury vapor then will participate in the atmospheric mercury cycle, The low solubility of elemental mercury in water helps to minimize mercury leaching from tailings, however, conversion of elemental mercury to more soluble forms by bio-geo-chemical processes can enhance its mobility posing increased health risk.

Jan 1, 2003

By Milton Manrique

The thermal decomposition of zircon concentrates in a non-transferred arc thermal plasma flow reactor was investigated. The plasma torch was operated using argon-helium and argon-nitrogen mixtures as plasma gases. The effect of power, feed rate and zircon particle size was studied. Products were characterized by XRD, SEM, TEM and chemical analytical techniques. The average size of the product was in the submicron range. Free energy minimization plots were used to predict the behavior of the system under different operating conditions. A kinetic model to describe the different stages of the thermal decomposition process is proposed. The results of this investigation showed a significant segregation process where the zirconia-rich product is collected in the reactor while the silica-rich product is collected in the filter. TEM analysis indicated that silica vapor is condensed on the surface of the zirconia particles.

Jan 1, 1996

By Zhihong Liu

Monodisperse micron size nickel oxalate particles with rhombohedron morphology were prepared from condensed Ni(OH)2 suspension by a novel gel-sol process proposed by one of the authors. Firstly, condensed nickel hydroxide gel was formed by fast adding 1 mol dm-3 NaOH solution into 0.2 mol dm-3 nickel chloride solution, and then oxalic acid solution with a concentration of 0.25 mol dm-3 was dropped into the gel drop wise through a pump equiped with a pH controller under preset pH value, and in this process, Ni(OH)2 gel was converted gradually into monodisperse nickel oxalate sol. The formation of the nickel oxalate particles was found to proceed through a dissolution-recrystallization mechanism from the nickel hydroxide gel. The product particles exhibited rhombohedron like shape with micron size long axis and sub-micron size short axis. The effects of such factors, as temperature, surfactants, et al, were evaluated experimentally on the particles sizes and morphologies.

Jan 1, 2006

By Darryl Lovato, Ramiro Pereyra, Daniel S. Schwartz

"During an annual inventory of nuclear material, a plated steel container which contained plutonium oxide failed. The container had been packaged for temporary storage but had been overlooked and remained in storage for more than 23 years. Although it was determined that the failure occurred through the slip-top rim, a metallurgical evaluation was requested to help to determine the integrity of the container.Optical metallography and scanning electron microscopy were used to analyze the character and degree of corrosion in the container. The depth of corrosion, measured at approximately 10 µm, did not pose a threat to the integrity of the container. However, the corrosion morphology and chemistry did suggest that a galvanic cell had developed between the tin and steel from the condensation of water. The morphology also suggests that the attack of the steel took place over a series of cycles due to changes of the environment.IntroductionMetallographic analysis was requested as part of the investigation into the mechanism of the failure of a slip-top container (#38621) containing plutonium oxide (PuO2) powder. The container had leaked during a special nuclear material (SNM) annual inventory causing contamination and closure of the vault. A photograph of the container and interior container is shown on the right in Figure 1. An initial investigation established that the source of contamination was the consequence of the failure of multiple layers of containment. Initially by the deterioration of the interior plastic bottle and polyvinyl chloride (PVC) bagout bag, and finally through the lid and steel container interface at a location where tape had not adhered properly [1]. Although the source of the breach was established, it was determined that metallographic analysis was important to establish the extent of deterioration of the steel container."

Jan 1, 2008

By R. J. Wesely

In recent years the trend in copper smelting has been to expand existing smelters to increase their throughput. New smelters under consideration are large, typically in excess of 200,000 tons per year of copper. Despite this trend to larger smelters there are a number of conditions where a much smaller smelter can be economically viable. This paper examines these conditions and outlines the process concepts for a small smelter treating from 20,000 to 100,000 tons per year of copper.

Jan 1, 2000

By Shengli Wu, Mingyin Kou, Laixin Wang, Zhe Wang, Xinliang Liu

The sticking behavior of iron ores in the shaft furnace is one of the most important problems in the COREX melting progress, which directly influence the smooth operation and productivity of shaft furnace. Therefore, it is of great importance to study the sticking behavior of pellets in COREX shaft furnace. The results showed that porous metallic iron produced at the interface of pellets samples was the main reason for the sticking of pellets in the COREX shaft furnace. The SI (sticking index) and metallization rate increased with the reduction temperature and gas flow, and decreased with melting rate. However, the SI of pellets in the COREX shaft furnace could be decreased by the proper match of melting rate and reduction temperature, reduction temperature and gas flow, while the metallization rate of pellets were kept at a certain level. Furthermore, the matching of melting rate and reduction temperature was more effective than the matching of reduction temperature and gas flow.

Jan 1, 2016

By M. D. Light

An intelligent control system (ICS) is being developed for ferrous iron oxidation by Thiobacillus ferroxitdans. The ICS provides computerized data acquisition and' control of process variables (temperature, Eh, pH, dissolved oxygen arid carbon dioxide concentrations and dilution rate) to maintain the ferrous iron oxidation at the highest possible rate. The ICS uses fuzzy logic for analysis of data inputs and implementation of control strategies. T:his paper provides preliminary information on the development of the ICS and? its operation.

Jan 1, 1991

By Guy Deschênes

Thiourea solutions can be used as leach liquors to treat gold ores or slimes. It is also efficient to elute resins or strip solvents that were loaded in cyanides solutions. The hydrogen pressure reduction is a practical step to recover gold and silver from leach solutions, and strips and eluates without any destruction of thiourea. It is a critical point because these processes have to consider the recycling of the liquors to be irore economical. The effect of temperature, pressure, acidity, compotation of the solution and the nature of catalysts on pressure reduction by hydrogen were investigated. An electranetallurgical study was? carried out to investigate the mechanism. The composition of the products was studied by different analytical methods. The process shows a good selectivity to precipitate gold and silver in a thiourea solution containing iron and copper. Gold and silver concentrations can be decreased to 0.2 ppm and 0.1 ppm at respectively 70 KPa H2 and 28°C. No decomposition of thiourea was evident during the tests. Metals such as nickel powder or platinum activate the reaction and improve the reduction.

Jan 1, 1989

By Christopher M. Moore

DK Recycling und Rohelsen GmbH converts 380 000 annual tonnes of iron containing waste materials Into pig Iron. Zinc Is the main reason that these materials are classified as waste. The materials are processed In the conventional way by making sinter which is then smelted in a blast furnace to foundry grade pig iron. The trick lies not in the unit operations which are quite standard but rather In the modifications made to the plant and operating procedures to cope with the much higher levels of tramp elements.

Jan 1, 1995

By Katsuyoshi Kondoh

The synthesis processing of Mg2Si or Mg2SiIMgO at lower temperature from the elemental magnesium alloy powder/chips and Si or SiO2 powder mixture was established via the repeated plastic working (RPW) based on Powder Metallurgy (PIM) process. RPW is much effective on the mechanical breakage of MgO surface films, which prevent from the solid-state reaction between Mg and Si powder. The solid-state synthesized Mg2Si particle of 200nm-2um is extremely fine, compared to that via the conventional casting process, causing the coarse one of 50-100um. This is because of not coarsening during the solid-state synthesis of Mg2Si. By using in-situ fonning process of Mg2Si via RPW and pre-heating before hot working such as extrusion and forging, the magnesium composite material with Mg2Si or Mg2Si/MgO dispersions was developed in employing Si or SiO2 particles, respectively. For example, when employing AZ31 chips as raw materials of the matrix, it has low density of 1.85g/cm3 and extremely superior mechanical properties, such as tensile strength over 350MPa with 5-10% elongation and Young's modulus of 47-50GPa, to the conventional Mg-Al-Zn alloys. The Mg composite alloy wires and pipes were produced via the hot extrusion process in the manufacturing plant, and also showed excellent mechanical properties.

Jan 1, 2003

By N. A. Warner

To filly secure the environmental and social acceptability benefits of making a sulphide smelting facility and its ancillary sulphuric acid plant or other means for fixing sulphur, a virtually zero gas emission operation, it will be necessary to utilise exclusively technically pure oxygen. The strategy proposed for preventing the smelter from overheating involves highly efficient energy transfer by promoting sulphur trioxide formation at a relatively higher temperature than normal. A closed-loop gas circuit uses an eductor system actuated by the process oxygen to recirculate sulphur trioxide and unconverted sulphur dioxide back to the smelter, the endothermic dissociation of sulphur trioxide becoming a major contributor to the removal of excess heat. The only gases leaving the system relate to the bleed of nitrogen impurity introduced in the tonnage oxygen.

Jan 1, 1998

By Qingyu Deng, Shiwei Ma, Guibao Qiu, Hua Wang

"The flow behavior of the blast furnace slag bearing titanium, like viscosity, play an importance role during the iron-making process with the vanadium-titanium magnetite, which is a very special minerals in Panzhihua, China. The dependency of the viscosity on the chemical composition like TiO2, Al2O3, MgO, binary basicity (CaO/SiO2), temperature, reaction time were studied. The experiments showed that the viscosity decreased with the increase of TiO2, MgO content and binary basicity, and it increased with the increase of Al2O3 content and temperature. The viscosity showed a slight decrease within 60mins’ reaction with graphite crucible, however, it increased rapidly afterwards with the formation of Ti(C, N).IntroductionThe ordinary iron ore has been an essential part of raw materials for vanadium-titanium magnetite smelting in Panzhihua to avoid a series of problems, such as slag thickening, adhesive bond of slag and hot metal, etc. The ratio of vanadium-titanium magnetite has been decreased gradually since 1970s, and has down to about 65% now. However, with the substantial appreciation of price of imported ordinary iron ore, Panzhihua Iron and Steel Group aims to increase the ratio of vanadium-titanium magnetite and decrease the dependence on ordinary iron ore in order to lower the cost of smelting process."

Jan 1, 2012

By Richard A. Shulkosky

The American Iron and Steel Institute (AlSO, in conjunction with the U.S. Department of Energy (DOE) jointly funded the development of a mechanical properties model for Hot Strip Mills. INTEG process group, inc. validated an enhanced version of the model under a project funded by the AlSI/DOE Technology Roadmap Program (fRP). The Hot Strip Mill Model (HSMM) version 6.0 allows users to easily set-up their mill configuration, simulate a rolling mill schedule and calibrate the model for a variety of grades of steel. Starting from reheat furnace drop out, the model simulates roughing mill stands (reversing and continuous), heat retention equipment (coil box and covers), finishing mill stands (tandem and Steckel mills), the run out table and the mill exit area. The HSMM uses a series of physical models to calculate both the thermo-mechanical and the microstructure evolution of steel being processed in a hot mill to predict its final mechanical properties. The enhanced HSMM was validated using a multitude of samples from several steel companies. Excellent agreement was obtained for tensile strength. The supporting steel companies have utilized the model for a variety of practical applications. Keywords: Process Modeling, Microstructure Evolution, Mechanical Properties

Jan 1, 2003

By Fuqiang Zheng, Shuai Wang, Ting Duan, Yufeng Guo, Tao Jiang, Andrew Yakovlevich Travyanov

Organic compound binder can effectively enhance the strength of green pellet and reduce the addition amount of binder during pelletizing. However, compared with traditional bentonite binder pellet, the compressive strength of the preheated and roasted pellets significantly declined. It is of significance to resolve this problem for the application of organic compound binder. In this paper, magnetite concentrate was used as raw material, carboxymethyl cellulose (CMC)- bentonite compound was used as binder, characteristics of preheated and roasted pellets and the effects of additives on that were systematically studied, The results show that sodium acetate can effectively improve the characteristics of the finished compound binder pellets. The compressive strength of the preheated and roasted pellets were increased by 52/N·p-1 and 342/N·p-1 respectively when the addition amount of sodium acetate is 2.2%wt of compound binder. Moreover, sodium acetate has no adverse effect on pelletizing process and drying characteristics of green balls.

Jan 1, 2015