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By N. J. Tannyan

Laboratory bath smelting tests were conducted to determine the feasibility of smelting nickel- copper concentrate directly to a low iron matte in one step. Concentrate, air/oxygen and a silica flux were fed to a matte-slag bath kept in MgO crucibles at I 300°C. Various oxygen enrichments and smelting rates were used to maintain 0.5 to 2 wt% iron in the product matte. The slag losses are comparable to those obtained under similar industrial conditions. Due to the highly oxidizing conditions required to produce mattes with low iron contents, it is not recommended to target iron contents below about 2% in the matte. The specific bath smelting rates were equal to or higher than those in various industrial bath smelting processes.

Jan 1, 2003

By Jian Pan, Zhen He, Deqing Zhu, Shouyan Yue

"The differences of raw material characteristic among six kind of iron concentrates and the influences on ballability were studied from the aspect of the size distribution, specific surface area and particles morphology. The results show that the specific surface area of iron concentrates has crucial influence on ballability, and the effective method of improving ballability for weak ballability iron concentrate has been found. It is of important guidance for Chinese steel mills to import and use iron concentrate from the whole world.IntroductionChina's steel industry has developed rapidly in recent years, crude steel production in 2011 is an unprecedented 683 million tons, which is almost half of the world crude steel production, and it is equivalent to the total sum production of the nations which rank at 2,3,4,5 and 6 in the world [1]. In order to match the development of steel industry, the blast furnaces are becoming larger and more modernization, therefore charging burden of higher quality is requested, and the reasonable blast furnace burden structure is more and more important, at the same time, for iron ore powder sintering process's continuous improvement and development, another method providing ""concentrate"" for blast fumace-pelletizing is also taken seriously. The grate-kiln method of pelletizing has achieved great development for its unique advantage, and in just a few years, there are over 60 rotary kiln production lines have built or being built in China, the sum of pellets has reached to more than 140 million [2, 3]. The rapidly growth of pelletizing yield demands diverse source of pellet, which include not only domestic magnetite concentrate, but also imported hematite which is high in iron and low in silicon. Usually the ratio of imported hematite concentrate increased gradually. The imported hematite concentrate has high grade and fine particle size (the content of -0.074 mm mostly higher than 90%), but the ballability of part of the concentrates is poor."

Jan 1, 2013

By Musa Karakus

Reflected light microscopic (RLM) examination of dust particles from lead and copper smelters can effectively characterize their mineralogy, texture, and origin. Scanning electron microscopic-energy dispersive spectroscopic (SEM-EDS) analysis provides confirmation of the optical identifications and chemical data on the phases. Studied lead smelter dust samples were from the: I) blast furnace, 2) sinter plant scrubber, 3) sinter plant crusher, 4) dross furnace, and 5) refinery. Phases identified included galena fragments, melted PbS, metallic Pb and Cu, Cu-Ni, Cu-Zn, Zn-Ag, Zn-Cu-Ag, Ni-Cu-Sb, and Ni-Cu-Zn-Ag metal alloys, Ni-sulfide, Cu-sulfide, and Cu-Pb-sulfide dross .phases; slag and sinter particles, coke fragments, unreacted original feed phases: pyrite, chalcopyrite, sphalerite, siegenite, bravoite; and oxidized particles: iss, bornite, chalcocite, covellite, magnetite, hematite, and goethite. Dust from a secondary copper refinery were found by RLM and SEM to consist of tenorite, cuprite, cassiterite, two silicate phases. Magnetite, hematite, Fe-Al-Cr-Mg spinel, periclase, forsterite, and wollastonite were derived from the furnace linings during initial cleaning.

Jan 1, 1992

By John E. Litz

Metal-bearing flue dusts are produced by some ferrous and non-ferrous industries. Many dusts are being or can be treated for recovery of metal values. Operating and proposed flowsheets for the most common dusts are reviewed. Advantages, disadvantages, product marketability, and cost implications are discussed for each flowsheet.

Jan 1, 1992

By Y. Maeda

Non-ferrous smelting furnaces generally lnstal1 a gas cooling system for treatment of waste gas containing S02. From the point of view of corrosion resistance and recovery of waste heat, the high pressure boiler system Is the best way to cool gas, however this system requires high Initial investment and relatively higher operating costs. Because the feasibility of this boiler system greatly depends on the smelting process and scale, other lower temperature systems, e.g. water-cooled Jacket system, are more suitable If the smelting process does not produce enough steam nor generate enough electricity to compensate operating cost. In addition, the water-cooled Jacket system Is simple in structure and easy to operate. For those reasons, it is applied widely. A new smelting furnace. was planned tin our factory and It was necessary to install waste gas cooling equipment. In our case, a water-cooled Jacket system was mo11e feasible because of the low gas volume and high dust content. H was also expected to operate without maintenance for ten years. On the other hand, some leakage problems with the water-cool1ed Jacket had been experienced In the past. That is because S02 in the waste gas changed into sulfuric acid which corroded the Jacket material, As the first step, several data from actual usage were reviewed to throw light on the corrosion process, and an appropriate procedure to determine the operating temperature of cooling water was obtained. For the basis of this study, a water-cooled Jacket system was newly designed and tested for three months in a pilot plant. After this system's performance was confirmed, It was installed In a new furnace as a commercial pl.ant. After one year of operation, the initial thickness of carbon steel Jacket remains almost the same.

Jan 1, 1992

By Jie Li

Series of carbon compounds as anode materials were prepared for super lithium ion capacitor using graphite and active carbon (AC) as raw materials. Their electrochemical properties were investigated by constant current charge-discharge test. The results showed that the compound anode had good capacitive performance as well as Li-ion battery performance. The potential of the capacitor could be as high as 3.5V vs Li/Li+ when compared with 2.5V vs Li/Li+ in the AC-AC capacitor, accordingly, the energy density increased from 21.7Wh/kg to 40.3Wh/kg. The compound anode also had excellent rate performance that as the current density increasing from 0.1A/g to 1A/g,the capacitance decreased only 1.3F/g, and good cycle performance that the capacitance holding remained 96.7% after 10 times cycles even at the highest potential of 3.5 V vs Li/Li+.

Jan 1, 2009

By Xuefeng She, Qingguo Xue, Jingsong Wang, Guang Wang

Iron nugget could be got at high temperature using carbon composite pellet, which were made by the mixture of ludwigite and reducing agent. In order to reduce sulfur content in the nugget, effects of additives on the desulfurization was investigated. The sulfur content could be dramatically reduced if the CaO was introduced into the pellet and the sulfur content was as low as 0.046wt.% when the addition amount of CaO was 5wt.%. However, the melting separation of pellet became increasingly difficult and the yield of iron decreased when CaO content in the pellet gradually increased. Na2CO3 could also reduce the sulfur content in the iron nugget and made the iron and slag separate difficultly as well. When 6wt.% Na2CO3 was added into the pellet, the pellet was too difficult to melt separation and the sulfur content in the nugget was 0.084wt.%, which didn’t meet the need of steel making.

Jan 1, 2015

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 Yapeng Zhang, Zhiwen Shi, Chaoquan Yao, Fei Wang, Xinyu Li, Jianliang Zhang

A great deal of iron ores which have special elements have been applied in the sintering process with the decreasing of high-grade quality iron ores resources. In this paper, the laterite nickel ores were added into three different kinds of iron ores respectively to make liquid phase formation research by software of Factsage and high temperature characteristic sintering experiments. The results showed that the adding proportion of laterite nickel ores should be less than 15% when the high temperature properties of the mixing ores were well. Increasing the mixing ration of laterite nickel ores in the sintering blending would play an important role in the reduction of the sintering cost.

Jan 1, 2015

By Chuanyu Feng

In this paper, a load-based micro-indentation technique suitable for field applications was developed. This technique bears the same theoretical background as traditional load-depth sensing indentation, and does not need any direct measurement of indentation depth or contact area. The removal of this requirement will reduce much of the cost associated with traditional instrumented indentation. To demonstrate the feasibility, a portable indentation system suitable for online material characterization was developed. Design issues of the portable unit were discussed and preliminary results using the portable unit were also presented.

Jan 1, 2009

By Youqi Fan

Complicated copper oxalate precursor powder was prepared using ammonium oxalate as precipitating agent in the Cu(II)-C2O42--NH3-NH4+-H2O system. The composition and morphology of the powder are characterized by chemical analysis, X-ray Diffraction (XRD), scanning electron microscope (SEM), infrared spectroscopy (IR). The effects of temperature, copper ion concentration, pH value are investigated. It?s indicated by the experimental results that precursor of copper oxalate is prepared below a critical pH value, whereas the precursor turns to be a complicated copper salt combined with NH3 while over the pH value. Probable chemical formula CuC2O4?x(NH3)?yH2O can be assumed which x and y are relation to experimental conditions. Technological parameters, such as temperature, initial copper concentration and solution pH value, have significant effects on particle size, morphology and dispersion of precursor powder. By controlling certain technological conditions, various morphologies of precursor, pie shape, spindle shape and rod shape can be synthesized.

Jan 1, 2009

By Xiao-hui Fan, Xu-ling Chen, Zhi-yuan Yu1, Guanghui Li, Min Gan, Yun-song Huang, Tao Jiang

Compared with the traditional de-NOx processes by cleaning the waste gas, a new approach for reducing the formation of NOx during sintering process is proposed. Since more than 90vol% of NOx comes from the fuel combustion, the influence of sintering coke breeze pretreated by CO(NH2)2 additive on the NOx emission is researched. As adding CO(NH2)2, the reduction agents (NHi) are generated during the pyrolysis of CO(NH2)2, which reinforce the NOx reduction, And the appropriate content of CO(NH2)2 is 1.0 mass% of coke breeze.

Jan 1, 2015

By Thenepalli Thriveni, Ch. Ramakrishna, Yujin Jegal, Ji Whan Ahn, Jyothi Rajesh Kumar

In alumina production or alumina refining, bauxite is converted to alumina (aluminium oxide) The rare-earth elements (REEs) are a group of 17 chemically similar metallic elements (15 lanthanides, including scandium and yttrium). Rare earth elements play a key role in many industrial applications, petroleum refining, clean energy, automobile, electronics, and defense applications. These rare earths are essential to the success of green technologies. China today controls more than 95 percent of the rare-earth supplies and nearly all rare-earth refining and after 2009 year rare earths crisis raises due to China’s export restrictions and growing internal demand for rare earth elements. The extraction of gallium and yttrium from Korean red mud (KC red mud) by selective acid leaching was explored. The recovery of gallium and yttrium from a leach solution of the Korean red mud using solvent extraction was studied. A number of extractants were investigated for the extraction of those mentioned two rare earth elements and also we proposed a flow sheet of rare earth elements respectively. The toxic heavy metals presented in KC red mud were removed by CO2 stabilization.

Jan 1, 2015

By Yuanbo Zhang, Huanpeng Mi, Guanghui Li, Binjun Liang, Zhiwei Peng, Tao Jiang

Ludwigite ore has not yet been utilized on an industrial scale due to its complex mineralogy and fine mineral dissemination. In this study, sodium salts were employed to enhance the separation of iron and boron by reductive roasting-magnetic separation. It was found that the separation of iron and boron as well as the iron grade and recovery were significantly improved b y the addition of Na2SO4 or Na2CO3. Under the reduction temperature of 1050 °C, reduction time of 60 min and magnetic intensity of 0.1T. Compared with the inexistence of sodium salts, the iron grade and recovery of the magnetic concentrate increased from 83.3% and 88.6% to 93.2% and 95.1%, respectively, by adding 6% Na2CO3. The XRD and microstructure analyses indicated that the iron oxides were transformed into metallic iron and the average metallic iron grains were grown to over 40μm which was beneficial for separation of metallic iron from gangue.

Jan 1, 2016

By Yongqi Sun, Zuotai Zhang

Hot slags, at the temperatures of 1450-1650 oC, carry a substantial amount of high quality thermal energy, which represents the largest undeveloped energy source in the steel industry. However, the waste heat recovery rate in China is less than 2%; thus there is a great potential of waste heat recovery. In this study, we investigated a chemical method to extract the waste heat from high temperature blast furnace slags, i.e., sludge gasification. Sewage sludge, another substantial waste produced in the municipal system, need to be timely disposed, the organics of which could be gasified using the waste heat in the slags for the purpose of syngas production. Both the kinetics and thermodynamics of the sludge gasification process were clarified here. Most importantly, an integrated system composed of multiple systems such as the steel industry, the cement industry, the municipal system and the chemical engineering industry, was analyzed in this study.

Jan 1, 2016

By Lu Lin, Yanping Bao, Xiang Li, Linzhu Wang, Xiaobai Yan

The results showed the microinclusions were mainly Al2O3 and sulfide inclusions from tapping to the beginning of LF refining. Al2O3 inclusions were modificated into calcium aluminates after calcium treatment. Lots of spherical calcium aluminates composite inclusions containing MgO, TiO2 and MnS were found after soft blowing and during tundish metallurgy and left in the slab which caused the defects of beam plates. Pure Al2O3 inclusions were observed again after soft blowing 8min. Average sulfur content in inclusions decreased because of the high desulfurization ability of refining slag. Average Ca/Al ratio value in inclusions increased during LF refinging because of the reduction of CaO in slag by carbon and it increased obviously during the process of soft blowing 8min because of the dissolusion of calcium wire.

Jan 1, 2015

By José Brant, Douglas Torres, Rogério Navarro, Rodrigo Souza, Eduardo Brocchi

The steelmaking process requires the input of ferro-alloys to implement the adjustment of some elements composition in the final product. In the particular case of stainless steel production, the high carbon FeCr alloy stands out as one important precursor. However in the production of this material a certain quantity of fine powder with remarkable chromium and carbon content is also generated, which, in turn, could be processed through alkaline roasting in order to selectively recovery this element in a subsequent aqueous route. In the present work, this process is investigated, using excess of NaOH as oxidizing agent, and H2O2 for precipitating chromium as Cr(OH)3, which is next calcinated to Cr2O3. According to the results, the global achieved recovery has shown to be around 98%, suggesting that the proposed route can be seen as a potential process for chromium oxide production from the mentioned fine powder.

Jan 1, 2015

By Feng Wang, Guojing Shi, Yangyang Xie, Zizong Zhu, Qiang Wu

The coal chars from northwestern part of China are characterized with high reactivity and low strength after reaction. Four type of coke-making coals selected from northwestern part of China were studied by proximate analysis, ultimate analysis, vitrinite reflectance analysis, and FTIR with curve-fitting analysis to obtain information on their chemical composition and chemical structure. The results show that the studied coals have relatively high values of final contraction of coke residue index (x) and relatively low values of maximum thickness of plastic layer (y) and average vitrinite reflectance. Based on the curve-fitting analysis of FTIR spectra, the aliphatic carbon (Cal), the aromatic carbon (Car), and the molecular structural parameters such as CH2/CH3, fa, Hal/Har, and (R/C)u are determined. The results of curve-fitting analysis indicate that the studied coals are characterized by a large amount of oxygen-containing functional groups and aliphatic side chains.

Mar 1, 2018

By Naiyang Ma

Along with steel production, various steelmaking slags are constantly generated at considerably high rates. In general, steelmaking slags are not categorized into hazardous materials and do not cause any environmental issues. Therefore, recycling of steelmaking slags is often aimed at creating values by using the slags to replace high-cost raw materials. Chemical compositions and particle size distributions of slag products from steelmaking slags will determine what raw materials the slag products can replace. Consequently, maximizing the values of steelmaking slags will require to produce slag products with the highest values and to process the slags with the lowest costs. In this paper, several slag processing processes are assessed based on maximization of the values of the steelmaking slags.

Mar 1, 2017

By Shiju Zhang, Yongnian Dai, Songli Liu, Kuisong Zhu, Wenhui Ma, Li Cao

There is an abundance of vanadium-titanium magnetite in Panzhihua, China, which contains more than 8.73 x 10^8 tons of TiO2 accounting for 90.6% of the national reserves. To fully utilize Panzhihua titanium resources, many processes were proposed. The present status and future development of technologies for comprehensive utilization of vanadium-titanium magnetite including blast furnace, electric smelting, and ilmenite upgrading processes are reviewed.

Mar 1, 2017