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Efficient removal of Al(Ⅲ)and P507 from high concentration MgCl_(2)solution based on in-situ reaction strategy

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Transactions of Nonferrous Metals Society of China 2024年第9期34卷 3042-3053页

作者： Qiang WANG Meng WANG Zong-yu FENG Yong-qi ZHANG Xiao-wei HUANG xiang-xin xue National Engineering Research Center for Rare Earth GRIREM Advanced Materials Co.Ltd.Beijing 100088China School of Metallurgy Northeastern UniversityShenyang 110819China General Research Institute for Nonferrous Metals Beijing 100088China GRIMAT Engineering Institute Co. Ltd.Beijing 101407China

For a highly efficient recycling of a wastewater containing a high concentration of MgCl_2,Al(Ⅲ)and P507 were scheduled to be removed in *** this study,the in-situ removal of Al(Ⅲ)and P507 from a high concentration MgCl_(2)solution at different pH values and Al/P molar ratios was *** results showed that P507 formed organic complexes of Al_x(OH)_y~(Z+)-P507 at pH of *** pH of 4.0-5.0,Al(Ⅲ)precipitated and transferred into Al(OH)_(3)with a flocculent amorphous *** sites on the Al(OH)_(3)surface enhanced the removal efficiency of *** pH of 6.0-6.5,Al(Ⅲ)and Mg(Ⅱ)formed layered crystalline Al(OH)_(3)and MgAl_2(OH)_(8with)small pore channels and fewer active sites,resulting in a reduced removal efficiency of *** the Al/P molar ratio exceeded 13 and the pH was between 4.0 and 5.0,the removal rates of both Al(Ⅲ)and P507 were higher than98%,while the concentration loss of Mg(Ⅱ)was only 0.2%-0.9%.

关键词： in-situ removal Al(III) P507 MgCl2 solution pH Al/P molar ratio

Diffusion coefficient of Ti^4+ in calcium ferrite/calcium titanate diffusion couple

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International Journal of Minerals,Metallurgy and Materials 2020年第9期27卷 1216-1225页

作者： Wang Wei Hong-rui Yue xiang-xin xue School of Metallurgy Northeastern UniversityShenyang 110819China

This study investigated the interdiffusion of calcium ferrite/calcium titanate system in the time range of 0-120 min by the diffusion couple method in a CO/N2 reducing atmosphere at 700℃.The results show that after the diffusion reaction occurred,no longitudinal agglomerations were present on the substrate surface on the calcium titanate *** the diffusion time was increased to 105 min,a net vacancy flow from calcium titanate to calcium ferrite might have occurred,causing the surface of the calcium ferrite substrate to *** thickness of the diffusion layer of the calcium ferrite/calcium titanate system was about 17-48μm,which conforms to the parabolic law of *** diffusion coefficient and the Ti^4+concentration in the calcium ferrite/calcium titanate system are *** shows an increase in the diffusion coefficient with the increase of Ti^4+concentration,and the diffusion coefficient value was in the range of 10^−12-10^−11 cm^2·s^−1.

关键词： vanadium-titanium sinter diffusion couple calcium ferrite calcium titanate diffusion coefficient

Optimized use of MgO flux in the agglomeration of high-chromium vanadium–titanium magnetite

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International Journal of Minerals,Metallurgy and Materials 2015年第4期22卷 371-380页

作者： Jue Tang Man-sheng Chu xiang-xin xue School of Material and Metallurgy Northeastern University

The optimized use of MgO flux in the agglomeration of high-chromium vanadium-titanium magnetite was investigated system- atically through sinter and pellet experiments. MgO was added in the form of magnesite. When the content of MgO in the sinter was in- creased from 1.95wt% to 2.63wt%, the low-temperature reduction degradation index increased from 80.57% to 82.71%. When the content of MgO in the pellet was increased from 1.14wt% to 2.40wt%, the reduction swelling index decreased from 15.2% to 8.6%; however, the com- pressive strength of the oxidized pellet decreased dramatically and it was 1985 N with an MgO content of 1.14wt%. This compressive strength does not satisfy the requirements for blast-furnace production. When all of the aforementioned results were taken into account, the sinter with a high MgO content （2.63wt%） matching the pellet with a low MgO content （less than 1.14wt%） was the rational burden structure for smelting high-chromium vanadium-titanium magnetite in blast furnaces.

关键词： magnetite ore pellets magnesia agglomeration burden sintering

Effect of Boron Concentration on Dynamic Recrystallization Behavior of Low-Carbon Steel

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Acta Metallurgica Sinica(English Letters) 2015年第7期28卷 931-939页

作者： Yong-Liang Gao xiang-xin xue He Yang Liaoning Key Laboratories of Ecological Utilization Technology of Boron Resources and Boron Materials Northeastern University

The dynamic recrystallization behavior of low-carbon steel containing three different amounts of boron（0.002,0.004,and 0.006 wt%） was systematically investigated under various experimental ***-carbon steel was exposed to temperatures ranging from 900 to 1100 ℃,strain rates from 0.1 to 10 s^-1,and inspection of the initial austenite grain size at 1150℃.The resulting stress–strain curves are observed to possess two classifications of behavior,dynamic recovery and dynamic recrystallization,while the initial austenite grain size increases directly proportional to boron ***,the characteristic points of the flow curves were analyzed by regression method in which the peak and critical stresses decreased in response to an increase in boron composition,indicating that a softening effect appears with the addition of *** the contrary,peak and critical strains increased as boron content increased,indicating that boron has the ability to delay the onset of dynamic ***,the kinetics model of dynamic recrystallization for three boron-treated steels was established.

关键词： Boron-treated steel Hot deformation Flow stress Dynamic recrystallization

Bainite Transformation of Low-carbon and Boron-containing Steel under Continuous Cooling

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Journal of Iron and Steel Research International 2014年第3期21卷 359-363页

作者： Zhi-hong ZHANG xiang-xin xue Institute of Metallurgical Resources and Environmental Engineering Northeastern University Liaoning Key Laboratory of Metallurgical Resources Circulation Science Liaoning Engineering Technology Research Center of Comprehensive Utilization of Boron Resources Liaoning University Key Laboratories of Ecological Utilization Technology of Boron Resources and Boron Materials

The effects of deformation temperature and strain on bainite transformation of low carbon steel and boron- containing steel were investigated under continuous cooling conditions by means of dilatometric measurement and mi- crostructure observation. The results show that with decreasing the deformation temperature from 1000 to 800 ℃ and increasing strains, bainite start temperature for boron-containing low carbon steel increases, whereas it decreases for low carbon steel under the same condition. The bainite microstructures are easily obtained for boron-containing steel deformed at different temperatures and different strains compared with plain low carbon steel. With increasing the continuous cooling rate, the bainite start temperature under deformed condition is about 20 ℃ higher than that under undeformed condition for boron-containing steel, but it changes slightly when the cooling rate is 20 ℃/s or more.

关键词： bainite start temperature boron containing steel phase transformation bainite

Preparation of V_2O_5 from converter slag containing vanadium

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Rare Metals 2018年第10期37卷 904-912页

作者： Chong Han Liang Li He Yang xiang-xin xue School of Materials and Metallurgy Northeastern University

Preparation of V2O5 from converter slag （CS） was investigated through roasting, leaching, extracting, and precipitating processes. The corresponding roles of the parameters during every procedure were analyzed in detail. （NH4）2SO4 and KHSO4 were used as fusing agents to transform compounds containing vanadium into soluble species. Mass ratio of （NH4）2SO4 to CS, mass ratio of KHSO4 to CS, and roasting temperature during the roasting process can significantly influence leaching rate of vanadium （LRV）. With H2SO4 as leaching agent, 99.2 % vanadium in CS can be leached out under the optimum leaching conditions, which mainly refer to liquid-to-solid ratio, H2SO4 concentration, leaching temperature, and leaching time. Extracting and back-extracting processes were introduced to purify the vanadium from the H2SO4 lixivium. Extracting rate of vanadium （ERV） greatly depends on iron powder concentration, pH, diisooctyl phosphate （P2O4） content, volume ratio of extractant to H2SO4 lixivium, and extracting time. By adding ammonium hydroxide, 94.0 % vanadium in back-extracting solution can be separated in the form of precipitates. The product from the roasted precipitate mainly consists of V2O5, the content of which is higher than 90.0 %.

关键词： Converter slag V2O5 Roasting Leaching Extracting

Effect of Cr2O3 addition on oxidation induration and reduction swelling behavior of chromium-bearing vanadium titanomagnetite pellets with simulated coke oven gas

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International Journal of Minerals,Metallurgy and Materials 2019年第8期26卷 963-972页

作者： Wei-dong Tang Song-tao Yang xiang-xin xue School of Metallurgy Northeastern UniversityShenyang 110819China School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051China

The oxidation induration and reduction swelling behavior of chromium-bearing vanadium titanomagnetite pellets(CVTP)with Cr2O3 addition were studied,and the reduction swelling index(RSI)and compressive strength(CS)of the reduced CVTP with simulated coke oven gas(COG)injection were *** results showed that the CS of the CVTP decreases and the porosity of the CVTP increases with increasing amount of Cr2O3 *** Cr2O3 mainly exists in the form of(Cr,Fe)2O3 solid solution in the CVTP and as Fe-Cr in the reduced *** CS of the reduced CVTP increases and the RSI of the reduced CVTP decreases with increasing amount of Cr2O3 *** limited aggregation and diffusion of metallic iron contribute to the formation of dense lamellar crystals,which leads to the slight decrease for reduction swelling behavior of reduced *** work provides a theoretical and technical basis for the utilization of CVTP and other Cr-bearing ores such as chromite with COG recycling technology.

关键词： chromium oxide oxidation induration reduction swellability coke oven gas chromium-bearing vanadium titanomagnetite pellets

Roasting decomposition of mixed rare earth tailings by CaO in reducing atmosphere

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Rare Metals 2017年第9期36卷 764-768页

作者： Shuai Yuan He Yang xiang-xin xue Yan Zhou School of Materials and Metallurgy Northeastern University Institute of Metallurgy Resources and Environmental EngineeringShenyang 110004China

In Baotou rare earth tailings ore, the grade of rare earth is close to that of the raw ore nearly. The rare earths are discarded in tailings dam caused by a serious waste of resources. First of all, the decomposition products of bastnaesite-and monazite-mixed rare earth tailings in CaO in reducing atmosphere were studied by means of X-ray diffraction（XRD）. The results show that the normal products are CeO2, Ce2O3, Ca5F（PO4）3, and Ce（0.75）Nd（0.25）O（1.875）, and there are no REPO4 and ***, the roasted product was extracted in HCl, and the relationship among roasting time,roasting temperature,CaO addition, and extraction temperature was studied by the quadratic regression-orthogonal analysis. Through analysis, the optimum process conditions of mixed rare earth tailings extracted are obtained as follows： roasting time of 60 min, roasting temperature of 800℃, CaO addition of 30%, extraction temperature of 80℃, and extraction ratio of 99.18%.

关键词： Mixed rare earth tailings Reducing roasting Leaching ratio

Isothermal reduction kinetics and mineral phase of chromium-bearing vanadium–titanium sinter reduced with CO gas at 873–1273 K

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International Journal of Minerals,Metallurgy and Materials 2018年第2期25卷 145-152页

作者： Song-tao Yang Mi Zhou Tao Jiang xiang-xin xue School of Metallurgy Northeastern UniversityShenyang 110819China School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051China Key Laboratory of Liaoning Province for Recycling Science of Metallurgical Resources Shenyang 110819China

Reduction of chromium-bearing vanadium–titanium sinter（CVTS） was studied under simulated conditions of a blast furnace, and thermodynamics and kinetics were theoretically analyzed. Reduction kinetics of CVTS at different temperatures was evaluated using a shrinking unreacted core model. The microstructure, mineral phase, and variation of the sinter during reduction were observed by X-ray diffraction, scanning electron microscopy, and metallographic microscopy. Results indicate that porosity of CVTS increased with temperature. Meanwhile, the reduction degree of the sinter improved with the reduction rate. Reduction of the sinter was controlled by a chemical reaction at the initial stage and inner diffusion at the final stage. Activation energies measured 29.22–99.69 k J/mol. Phase transformations in CVTS reduction are as follows： Fe_2O_3→Fe_3O_4→FeO→Fe; Fe_2TiO_5→Fe_2TiO_4→FeTiO_3; FeO·V_2O_3→V_2O_3; FeO·Cr_2O_3→Cr_2O_3.

关键词： sinter kinetics reduction mineral phase