随着我国氧化铝产量的不断增大,排放的赤泥量也日益增加,普通堆存处置的方式所带来的污染生态环境、占用土地资源等问题越来越突出。为有效富集赤泥中的铁,以山东某赤泥为研究对象,在矿石性质分析的基础上,进行了磁化焙烧—弱磁选工艺...随着我国氧化铝产量的不断增大,排放的赤泥量也日益增加,普通堆存处置的方式所带来的污染生态环境、占用土地资源等问题越来越突出。为有效富集赤泥中的铁,以山东某赤泥为研究对象,在矿石性质分析的基础上,进行了磁化焙烧—弱磁选工艺流程试验。结果显示:赤泥铁品位为37.37%,赤泥中铁主要存在于赤、褐铁矿中,赤、褐铁矿中铁占总铁的98.23%;赤泥在CO浓度30%、焙烧温度620℃、焙烧时间为20 min的条件下磁化焙烧,焙烧产品磨细至-0.038 mm含量70%,在磁场强度为85.6 k A/m条件下进行弱磁选,可获得铁品位47.01%、作业回收率73.01%的最终铁精矿。对获得的铁精矿进行铁物相分析、XRD分析和磁性分析可知,赤泥中的赤、褐铁矿在磁化焙烧过程中大部分被还原成磁铁矿,铁矿物磁性增强,进而可以通过弱磁选实现铁矿物与脉石矿物的分离。但是针对铁精矿中铁品位的继续提升与铝的脱除需要进一步的研究。展开更多
To comprehensively utilize the low-iron high-vanadium-titanium magnetite,a new method of vortex smelting reduction of vanadium-titanium magnetite was proposed,and the enrichment and reconstitution regularity of Ti-bea...To comprehensively utilize the low-iron high-vanadium-titanium magnetite,a new method of vortex smelting reduction of vanadium-titanium magnetite was proposed,and the enrichment and reconstitution regularity of Ti-bearing phases in the slag was investigated through X-ray fluorescence spectrometry,X-ray photoelectron spectroscopy,X-ray diffraction analysis,and optical microscopy.The phase diagram revealed that the preferential crystallization of MgTi_(2)O_(5) can be achieved by adjusting the CaO,MgO,and TiO_(2) contents of slag.The predominant Ti-bearing phases in the slag obtained from the reduction process are MgxTi_(3_x)O_(5)(0≤x≤1)and CaTiO_(3).FeTiO_(3) is present at carbon-iron ratio(CR)=1.3,while MgTi_(2)O4 and TiC are formed at CR=1.3.The enrichment of TiO_(2) in the slag increases first and then decreases as the CR increases,and at CR=1.1,the enrichment of TiO_(2) in the slag reaches 51.3 wt.%.Additionally,the concentrations of MgxTi_(3_x)O_(5)(0≤x≤1)and CaTiO_(3) in the slag,along with the grain width of MgxTi_(3_x)O_(5)(0≤x≤1),decrease with the increase in CR.展开更多
For improving the strength of pellets made of ultrafine and super-high-grade magnetite concentrates,the influence of basicity(CaO/SiO2 ratio)on the roasting and consolidation of pellets was investigated.The results sh...For improving the strength of pellets made of ultrafine and super-high-grade magnetite concentrates,the influence of basicity(CaO/SiO2 ratio)on the roasting and consolidation of pellets was investigated.The results showed that with the basicity of pellets increasing from 0.09 to 0.60,the compressive strength of both preheated and roasted pellets achieved an evident improvement from 502 and 2519 to 549 and 3096 N/pellet,respectively;meanwhile,the roasting time decreased from 15 to 9.min.The low-viscosity liquid phases were easily generated in fired pellets at the basicity range of 0.40-0.60 under the roasting temperature of 1240℃,filled the voids between hematite particles and tightened the bonding among particles,effectively restraining the generation of concentric cracks and decreasing the porosity of fired pellets;low-viscosity liquid phases facilitated the solid diffusion of hematite,leading to the formation of coarse hematite crystals and thicker connecting necks.展开更多
Oxidization mechanism in CaO-FeOx-SiO2 slag with high iron content was investigated by blowing oxygen into molten slag so as to oxidize Fe（Ⅱ）. The relationship between Fe（Ⅱ） content and oxidizing time at differe...Oxidization mechanism in CaO-FeOx-SiO2 slag with high iron content was investigated by blowing oxygen into molten slag so as to oxidize Fe（Ⅱ）. The relationship between Fe（Ⅱ） content and oxidizing time at different temperatures was obtained by chemical analysis. Microstructure of slag was observed by metallographic microscope and SEM. Phases compositions were ascertained by EDXS and XRD. Grain size and crystallizing quantity of magnetite（Fe3O4） were determined by image analyzer. The oxidizing kinetic equations were deduced. Confirmed by graphical construction method, Fe（Ⅱ） oxidizing reaction in CaO-FeOx-SiO2 slag system is of first order, and the reaction apparent energy Ea is 296.67kJ/mol in the pure oxygen and 340.30kJ/mol in air. The enrichment and crystal growth mechanism of magnetite（Fe3O4） phases were investigated. In oxidizing process, content of fayalite declines, while that of magnetite（Fe3O4） increases, and iron resources enrich into magnetite（Fe3O4） phase. All these provide a theoretical base for compressive utilizing of those slags.展开更多
Titaniferous magnetite ore is a kind of symbiotic complex ore which comprises ilmenite, magnetite, hercynite and magnesio-hercynite spinel minerals. The ore collected from eastern India was characterized by XRD, WDXRF...Titaniferous magnetite ore is a kind of symbiotic complex ore which comprises ilmenite, magnetite, hercynite and magnesio-hercynite spinel minerals. The ore collected from eastern India was characterized by XRD, WDXRF, SEM and M？ssbauer spectroscopy. The oxidation behaviour of fine ore was investigated by TG-DTA analysis under oxygen atmosphere. Subsequent isothermal oxidation experiments were carried out under oxygen and air atmospheres, holding the samples for different periods of time at different temperatures from 873 K to 1473 K. It was observed that ilmenite phase transformed to hematite and titanium dioxide at lower temperature, whereas ferric-pseudobrookite phase was found at higher temperature. Direct reduction of oxidized sample-coke cylindrical briquettes was successfully achieved for phase transition from titaniferous magnetite to iron and titanium dioxide at 1473 K.展开更多
文摘随着我国氧化铝产量的不断增大,排放的赤泥量也日益增加,普通堆存处置的方式所带来的污染生态环境、占用土地资源等问题越来越突出。为有效富集赤泥中的铁,以山东某赤泥为研究对象,在矿石性质分析的基础上,进行了磁化焙烧—弱磁选工艺流程试验。结果显示:赤泥铁品位为37.37%,赤泥中铁主要存在于赤、褐铁矿中,赤、褐铁矿中铁占总铁的98.23%;赤泥在CO浓度30%、焙烧温度620℃、焙烧时间为20 min的条件下磁化焙烧,焙烧产品磨细至-0.038 mm含量70%,在磁场强度为85.6 k A/m条件下进行弱磁选,可获得铁品位47.01%、作业回收率73.01%的最终铁精矿。对获得的铁精矿进行铁物相分析、XRD分析和磁性分析可知,赤泥中的赤、褐铁矿在磁化焙烧过程中大部分被还原成磁铁矿,铁矿物磁性增强,进而可以通过弱磁选实现铁矿物与脉石矿物的分离。但是针对铁精矿中铁品位的继续提升与铝的脱除需要进一步的研究。
基金financially supported by the National Natural Science Foundation of China (U1908225)the Fundamental Research Funds for Central Universities (N2225012 and N232405-06).
文摘To comprehensively utilize the low-iron high-vanadium-titanium magnetite,a new method of vortex smelting reduction of vanadium-titanium magnetite was proposed,and the enrichment and reconstitution regularity of Ti-bearing phases in the slag was investigated through X-ray fluorescence spectrometry,X-ray photoelectron spectroscopy,X-ray diffraction analysis,and optical microscopy.The phase diagram revealed that the preferential crystallization of MgTi_(2)O_(5) can be achieved by adjusting the CaO,MgO,and TiO_(2) contents of slag.The predominant Ti-bearing phases in the slag obtained from the reduction process are MgxTi_(3_x)O_(5)(0≤x≤1)and CaTiO_(3).FeTiO_(3) is present at carbon-iron ratio(CR)=1.3,while MgTi_(2)O4 and TiC are formed at CR=1.3.The enrichment of TiO_(2) in the slag increases first and then decreases as the CR increases,and at CR=1.1,the enrichment of TiO_(2) in the slag reaches 51.3 wt.%.Additionally,the concentrations of MgxTi_(3_x)O_(5)(0≤x≤1)and CaTiO_(3) in the slag,along with the grain width of MgxTi_(3_x)O_(5)(0≤x≤1),decrease with the increase in CR.
基金The authors want to express their gratitude for the financial support from the National Natural Science Foundation of China(No.51474161)would like to thank the Hunan Provincial Co-innovation Center for Clean and Efficient Utilization of Strategic Metal Mineral Resources,which supplied us the facilities and funds to complete the experiments.
文摘For improving the strength of pellets made of ultrafine and super-high-grade magnetite concentrates,the influence of basicity(CaO/SiO2 ratio)on the roasting and consolidation of pellets was investigated.The results showed that with the basicity of pellets increasing from 0.09 to 0.60,the compressive strength of both preheated and roasted pellets achieved an evident improvement from 502 and 2519 to 549 and 3096 N/pellet,respectively;meanwhile,the roasting time decreased from 15 to 9.min.The low-viscosity liquid phases were easily generated in fired pellets at the basicity range of 0.40-0.60 under the roasting temperature of 1240℃,filled the voids between hematite particles and tightened the bonding among particles,effectively restraining the generation of concentric cracks and decreasing the porosity of fired pellets;low-viscosity liquid phases facilitated the solid diffusion of hematite,leading to the formation of coarse hematite crystals and thicker connecting necks.
基金Key Project(50234040) supported by the National Natural Science Foundation of China
文摘Oxidization mechanism in CaO-FeOx-SiO2 slag with high iron content was investigated by blowing oxygen into molten slag so as to oxidize Fe（Ⅱ）. The relationship between Fe（Ⅱ） content and oxidizing time at different temperatures was obtained by chemical analysis. Microstructure of slag was observed by metallographic microscope and SEM. Phases compositions were ascertained by EDXS and XRD. Grain size and crystallizing quantity of magnetite（Fe3O4） were determined by image analyzer. The oxidizing kinetic equations were deduced. Confirmed by graphical construction method, Fe（Ⅱ） oxidizing reaction in CaO-FeOx-SiO2 slag system is of first order, and the reaction apparent energy Ea is 296.67kJ/mol in the pure oxygen and 340.30kJ/mol in air. The enrichment and crystal growth mechanism of magnetite（Fe3O4） phases were investigated. In oxidizing process, content of fayalite declines, while that of magnetite（Fe3O4） increases, and iron resources enrich into magnetite（Fe3O4） phase. All these provide a theoretical base for compressive utilizing of those slags.
基金financial support from Ministry of Steel SDF project, Government of India for funding and providing fellowship
文摘Titaniferous magnetite ore is a kind of symbiotic complex ore which comprises ilmenite, magnetite, hercynite and magnesio-hercynite spinel minerals. The ore collected from eastern India was characterized by XRD, WDXRF, SEM and M？ssbauer spectroscopy. The oxidation behaviour of fine ore was investigated by TG-DTA analysis under oxygen atmosphere. Subsequent isothermal oxidation experiments were carried out under oxygen and air atmospheres, holding the samples for different periods of time at different temperatures from 873 K to 1473 K. It was observed that ilmenite phase transformed to hematite and titanium dioxide at lower temperature, whereas ferric-pseudobrookite phase was found at higher temperature. Direct reduction of oxidized sample-coke cylindrical briquettes was successfully achieved for phase transition from titaniferous magnetite to iron and titanium dioxide at 1473 K.
