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Recovery of iron and calcium aluminate slag from high-ferrous bauxite by high-temperature reduction and smelting process

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International Journal of Minerals,Metallurgy and Materials 2016年第8期23卷 881-890页

作者： Ying-yi Zhang Wei Lü yuan-hong qi Zong-shu Zou College of Materials Science and Engineering Chongqing University State Key Laboratory of Advance Steel Processes and Products Central Iron and Steel Research Institute School of Material and Metallurgy Northeastern University

A high-temperature reduction and smelting process was used to recover iron and calcium aluminate slag from high-ferrous bauxite. The effects of w（CaO）/w（SiO_2） ratio, anthracite ratio, and reduction temperature and time on the recovery and size of iron nuggets and on the Al_2O_3 grade of the calcium aluminate slag were investigated through thermodynamic calculations and experiments. The optimized process conditions were the bauxite/anthracite/slaked lime weight ratio of 100：16.17：59.37, reduction temperature of 1450°C and reduction time of 20 min. Under these conditions, high-quality iron nuggets and calcium aluminate slag were obtained. The largest size and the highest recovery rate of iron nuggets were 11.42 mm and 92.79wt%, respectively. The calcium aluminate slag mainly comprised Ca_2 SiO_4 and Ca_（12）Al_（14）O_（33）, with small amounts of Fe Al_2O_4, CaAl_2O_4, and Ca_2Al_2SiO_7.

关键词： bauxite reduction smelting recovery rate calcium aluminate slag

Model of Iron Ore Sintering Based on Melt and Mineral Formation

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Journal of Iron and Steel Research International 2015年第4期22卷 288-296页

作者： Jun ZHANG Xing-min GUO yuan-hong qi Ding-liu YAN School of Metallurgical and Ecological Engineering University of Science and Technology Beijing State Key Laboratory of Advanced Steel Processes and Products Central Iron and Steel Research Institute

A model of iron ore sintering was built with consideration of fuel combustion, catalysis of sinter mixture as well as formation of melt and mineral, which was verified via sintering pot tests and showed a good fit to the experi- mental results. The effect of bed depth on temperature was reflected by the residence time in high-temperature zone, rather than the top value of the temperature, which was weakened by melt formation as well as hematite decomposi- tion. Moreover, the effect of bed depth, fuel content and distribution on sintering process was different, which was reflected by temperature profiles and the rule of calcium ferrite formation. The formation of melt as well as magnetite was a process which was decided by kinetic factors, while the formation of calcium ferrite was related to fuel blend- ing conditions, which is determined by thermodynamics when the fuel ratio inside sinter granules is low or fuel con- tent is high, otherwise, it is determined by kinetics.

关键词： sintering modell iron ore melt mineral composition fuel combustion

A New Technology for Copper Slag Reduction to Get Molten Iron and Copper Matte

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Journal of Iron and Steel Research International 2015年第5期22卷 396-401页

作者： Jun ZHANG yuan-hong qi Ding-liu YAN Hai-chuan XU State Key Laboratory of Advanced Steel Processes and Products Central Iron and Steel Research Institute

The change of iron composition as well as the removal of copper from iron was investigated in the reduction process, and a new way to deal with copper slag was proposed. The iron in copper slag exists mainly in the form of fayalite, and the copper sulfide content accounts for just about 50%. Therefore, the magnetic separation as well as grinding floatation method is not suitable, and a pyrogenic treatment on copper slag is necessary. The carhurization and desulfurization process is restricted to a degree within the carbon composite pellets, and copper matte phase pre- cipitates from copper slag in the reduction process, which is immiscible with molten iron and slag. The copper con- tent decreases to 0.4% as the carbon content in molten iron reaches 3.84%, and the removal ratio of copper from molten iron approaches to 80%. The reduction and sulfurization process can be eompleted in one step, and the copper is separated from iron based on the ternary system of iron-matte-slag.

关键词： copper slag reduction sulfurization matte

Reduction and melting behavior of carbon composite lateritic bauxite pellets

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International Journal of Minerals,Metallurgy and Materials 2015年第4期22卷 381-388页

作者： Ying-yi Zhang Jie Zhao yuan-hong qi Xiang-li Cheng Zong-shu Zou State Key Laboratory of Advance Steel Processes and Products Central Iron and Steel Research Institute School of Material and Metallurgy Northeast University

Direct reduction of low-grade lateritic bauxite was studied at high temperature to recover Fe and beneficiate AlzO3 slag. The re- sults show that a metallization rate of 97.9% and a nugget recovery rate of 85.1% can be achieved when the reducing and melting tempera- tures are 1350 and 1480℃, respectively. Moreover, a higher-grade calcium aluminate slag （A1203 = 50.52wt%） can also be obtained, which is mainly composed of ct-A1203, hercynite （FeAI：O4）, and gehlenite （Ca2A12SiO7）. In addition, high-quality iron nuggets have been produced from low-grade lateritic bauxite. The nugget is mainly composed of iron （93.82wt%） and carbon （3.86wt%）, with almost no gangue （slag）.

关键词： bauxite ore pellets direct reduction process melting behavior metallization

Characteristics and Mechanism of Reduction and Smelting-separation Process of Copper Slag

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Journal of Iron and Steel Research International 2015年第2期22卷 121-127页

作者： Jun ZHANG yuan-hong qi Ding-liu YAN Xiang-li CHENG Peng HE State Key Laboratory of Advanced Steel Processes and Products China Iron and Steel Research Institute Group

The characteristics And mechanism of the reduction and smelting-separation process of the copper slag were studied by investigating the variation ：rule of metallization ratio, yield as well as carbon content of iron nuggets. The formation of molten slag is necessary for slag-iron separation, And iron is in half-molten state during smelting-separa- tion process, the carbon content of which is about 1.25 %. Carburization occurs through direct contact between car- bon and iron in essence, no matter in solid or molten state. The carburization rate is slow below 1 200 ℃ , which is inhibited by the existence of slag. Residual FeO in molten slag tends to form fayalite with SiOz in the copper slag, which is the root cause for the low mehing temperature of copper slag. The addition of CaO improves the reducibility of the copper slag, but Al2 O3 addition has no obvious effect. The melting temperature of slag affects the carburiza- tion extent in solid state, while the content of FeO in molten slag affects that in molten state, both of which co-de termine the carbon content in iron nuggets.

关键词： copper slag reduction smelting-separation earburization iron nugget

Strength Activity Index of Air Quenched Basic Oxygen Furnace Steel Slag

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Journal of Iron and Steel Research International 2015年第3期22卷 219-225页

作者： Lei GAN Hai-feng WANG Xiu-ping LI yuan-hong qi Chun-xia ZHANG School of Metallurgical and Chemical Engineering Jiangxi University of Science and Technology State Key Laboratory of Advanced Steel Processes and Products Central Iron and Steel Research Institute

Air quenched basic oxygen furnace steel slag （BOF-SS） is processed at very high cooling rate, which is expected to have different cementitious properties from conventional slowly cooled BOF-SS. For this purpose, the strength activity indexes of air quenched and slowly cooled BOF-SS are investigated. The results reveal that, under the specific surface area （S） of 490 m^2/kg, the compressive strength activity index reaches 1.24 after 28 days with replacement of 15% air quenched BOF-SS and reaches 1.05 after 28 days with replacement of 20% air quenched BOF-SS and 30%granulated blast furnace slag （GBFS）. The cementitious activity of air quenched BOF-SS is obviously higher than that of slowly cooled BOF-SS, mainly because it contains more C3 S and glassy phases.

关键词： basic oxygen furnace steel slag strength activity index mineral characteristics cementitious property tricalcium silicate (C3 S)

Reduction of Carbon-bearing Pellets of Oolitic Hematite in a Shaft Furnace

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Journal of Iron and Steel Research International 2016年第3期23卷 210-219页

作者： Wei WU Jian-jun GAO Jia-qing ZENG yuan-hong qi Jian-chang WANG Xi-dong ZHANG Metallurgical Technology Research Department Central Iron and Steel Research Institute State Key Laboratory for Advanced Iron and Steel Processes and Products Central Iron and Steel Research Institute WU Xi Zhao Shun Stainless Steel Middle Plate Co. Ltd.

When carbon-bearing pellets of oolitic hematite are treated in a shaft furnace,some problems are typically encountered：the metallization ratio of the metal pellets is low;the carbon-bearing pellets bond with each other at high temperatures;and the separation of phosphorus from iron is *** solve these problems,experiments were conducted on oolitic hematite reduction in a resistance furnace and semi-industrial test shaft *** results showed that the metallization rate reached 90% or greater under the conditions of a reduction temperature of 1 150℃,an atmosphere of simulated flue gas,and a reduction time between 1.5and *** problem of high-temperature bonding among pellets can be solved by increasing the strength of the pellets,coating their surface with a surface transfer agent and maintaining an even temperature inside the shaft *** basicity of the ore blend exerted no obvious effect on the magnetic concentrate and phosphorus *** phosphorus content in the magnetic concentrate can be further reduced by improving the grinding capacity of the ball mills used in the *** the basis of the experimental results related to oolitic hematite reduction with carbon-bearing pellets in a shaft furnace,the experimental requirements were satisfied with an average 88.27%total Fe content and 0.581% P content in the pellets.

关键词： oolitic hematite carbon-bearing pellet metallization rate high temperature bonding resistance furnace shaft furnace phosphorus separation

Effect of Heat Treatment on Corrosion Behaviour of Amorphous Metal Fibers

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Journal of Iron and Steel Research International 2014年第11期21卷 1030-1034页

作者： Zhong-wang WU Zhi-chao LU Xiao-jun NI De-ren LI Shuo FENG yuan-hong qi School of Materials and Metallurgy Inner Mongolia University of Science and Technology China Iron and Steel Research Institute Group Advanced Technology and Materials Co.Ltd. State Key Laboratory of Advanced Steel Processing and Products Central Iron and Steel Research Institute

Amorphous metal fiber has high corrosion resistance and excellent mechanical properties, making it a kind of good material for reinforcing concrete matrix. The effect of heat treatment on the corrosion behaviour of Fe73- Cr6C9Si1P11 amorphous metal fibers in 0.5 mol/L He SO4 solution was investigated by electrochemical polarization analysis. Differential scanning calorimetry （DSC） was used to measure the thermal properties. The evolution of the crystallization process after heat treatment was identified by X-ray diffraction （XRD）. The results show that the α- Fe, Fe2 P and Fea P crystalline phases individually precipitate in the amorphous matrix with increasing annealing temperature. The as prepared amorphous sample shows high corrosion resistance with a lower passivation current density and a wider passive region. The corrosion resistance dramatically decreases after the annealing temperature is higher than 400 ℃.

关键词： amorphous material corrosion fiber electrochemical polarization

Design and calibration of a new high-definition three-dimensional laparoscopic system

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Frontiers of Information Technology & Electronic Engineering 2015年第1期16卷 79-84页

作者： Jia TANG Li-qiang WANG Bo yuan hong JIANG qi-ming ZHU State Key Laboratory of Modern Optical Instrumentation Optical Engineering Department Zhejiang University Hangzhou 310027 China

We present a high-definition （HD） 3D laparoscopic system including a dual channel optical system, two cameras, a camera control unit （CCU）, and an HD 3D monitor. This laparoscopic system is capable of outputting dual high-definition videos and providing vivid 3D images. A modified pinhole camera model is used for camera calibration and a new method of depth measurement to improve precision. The average error of depth measurement measured by experiment （about 1.13 mm） was small in proportion to the large range in distance of the system （10-150 mm）. The new method is applicable to any calibrated binocular vision system.

关键词： Dual optical channels Three dimensional Camera calibration Pinhole model Depth measurement Laparoscopicsystem