某大型铁钛矿区地下水环境现状调查与评价

根据该矿区重点部位地下水质分析数据,采用单因子标准指数法对该矿区地下水质进行了分析,显示除亚硝酸盐和高锰酸盐指数有超标现象外,该矿区地下水其余指标均能达到《地下水质量标准》中Ⅲ类标准水质要求,说明该矿区内地下水环境质量总体状况较好。

某大型铁钛矿区地下水环境现状调查与评价

通过对某大型铁钛矿区地下水环境现状的调查,并根据该矿区重点部位地下水质分析数据,采用单因子标准指数法对该矿区地下水质进行了详细分析,结果显示除亚硝酸盐和高锰酸盐指数有超标现象外,该矿区地下水其余指标均能达到《地下水质量标准》中Ⅲ类标准水质要求,说明该矿区内地下水环境质量总体状况较好。

攀枝花地区含钪钒钛磁铁矿尾矿提钪关键技术研究

这是一篇矿物加工工程领域的论文。攀枝花某钒钛磁铁矿尾矿中的钪主要以类质同象形式赋存于辉石和钛铁矿中,部分辉石及其他硅酸盐矿物嵌有钛磁铁矿,钒钛磁铁矿尾矿中的矿物嵌布关系复杂,性质相似,钪元素含量低而且分散。对该钒钛磁铁矿尾矿,采用擦洗-沉降预抛尾-选择性二段磨矿-阶段反浮选抛尾工艺,抛除的尾矿产率为30.32%,实现了有效抛尾;钪元素得到较好富集,钪含量由60.96 g/t提高到70.90 g/t,Sc_(2)O_(3)回收率为81.04%。

湖北某地石英-正长岩中的铁硅钛铈矿

Iron ehevkinite reported in this paper was discovered in a quartz syenite, which had intruded into Archaean marble, from a certain district in Hubei Province. It occurs as globular masses whose maximum weight can be as great as 1 kg. Iron ehevkinite has a black or pitch blaee color, with subconchoidal fracture. Specific gravity is 4.53±0.05. Microhardness 466.33-583.80kg/mm^2. Refractive index 2.02.It is metamiet, and the conversion temperature from metamiet state to erystallinity is 825℃. Chemical analyses give the following formula: (TR1/47Fe0.095^2+Th0.09Ca0.31U0.009Na0.11K0.01 Mn0.001)2.94(Ti1.44Fe0.57^3+Ta0.009Nb0.01)2.029(Si1.94Al0.06)2[O10.92(OH)1.05]12. It's chemical composition is characterized by a higher iron content (FeO+Fe2O3=17.58) in comparison with that in normal ehevkinite. Rare earth eontents, except for Ce, are also high, notably neodymium and lanthanum. The oxidation of Fe^2+ in iron chevkinite is caused by the water that had been subjected to irradiation and then found its way through fine cracks into the mineral The change in ionic radii involved in the oxidation of iron may be responsible for the metamietization of the mineral This interpretation accounts also for the eonstant association of a certain amount of water with metamiet minerals.

Crichtonite族矿物在我国的研究进展与冕宁铀矿的发现

回顾了锶铁钛矿（crichtonite）族矿物在我国的研究历史,从产状、物理性质、化学成分以及晶体结构等方面重点介绍了锶铁钛矿族新成员——冕宁铀矿。锶铁钛矿族矿物属三方晶系,结构通式为AⅫBⅥC18ⅥT2Ⅳ（Φ）38。冕宁铀矿是锶铁钛矿族第15个成员,产自牦牛坪稀土矿包子山煌斑岩破碎带中（N28°24’20″,E101°59’3″）,经验化学式为[□0.322(Pb0.215Ba0.037Sr0.036Ca0.010)0.298(Ce0.128La0.077Nd0.012)0.217(Na0.127K0.036)0.163]1.000(U0.4474+Mn0.293U0.1126+Y0.091Zr0.023Th0.011)0.977(Fe1.2243+Fe0.2432+Mg0.023P0.008Si0.006□0.4962.000(Ti12.464Fe5.2923+V0.1185+Nb0.083Al0.026Cr0.0173+)18.000O38.000;晶胞参数为a=1.03462（5）nm,c=2.08372（2）nm,V=1.93165（20）nm3,Z=3,空间群R3;晶体多呈半自形板状,粒径12 mm,黑色,条痕黑色,半金属光泽,不透明,性脆,贝壳状断口,解理、裂开和荧光性均不发育;莫氏硬度约为6,密度为4.62（8）g/cm3。由于铀等放射性元素的辐射,冕宁铀矿发育有不同程度的非晶质化。冕宁铀矿是锶铁钛矿族第一个A位以空位为主的矿物种。该矿物以其产地命名,已获得了国际矿物学会新矿物及矿物分类命名委员会（CNMNC-IMA）的正式批准（IMA 2014-072）。

Effects of Ti-and Mg-bearing minerals on hydrothermal formation of hydroandradite

The effects of Ti-and Mg-bearing minerals on the crystal structure,morphology,particle size distribution,and formation mechanism of efficient desilication product of hydroandradite(HA)during hydrothermal conversion in a synthetic sodium aluminate solution were investigated via X-ray diffractometer,scanning electron microscope and particle size analyzer.During HA formation,anatase,rutile,and periclase dissolved in sodium aluminate solution engage in ion substitution reactions between Ti4+and Si4+,and between Mg^(2+)and Ca^(2+),respectively.However,dissolved hydromagnesite cannot enter into the HA.The content of HA after the hydrothermal reactions changes slightly with the increase of anatase and periclase contents,but it notably decreases with increased quantities of rutile and hydromagnesite.Ti-bearing minerals reduce the particle size and enhance the specific surface area of HA,whereas Mg-bearing minerals exert the opposite effect.The morphology of HA with Ti-and Mg-bearing minerals changes from spherical particles to flocculent structure and hexagonal plate-like particles.

Effect of surface dissolution on flotation separation of fine ilmenite from titanaugite

The influence of surface dissolution on flotation separation of fine ilmenite from titanaugite was investigated through infrared spectroscopic （FT-IR） analysis and X-ray photoelectron spectroscopy （XPS） test. The results show that surface dissolution in weak acid solution is helpful to enlarge the floatability difference between ilmenite and titanaugite. In weak acidic solution, as sodium oleate mainly interacts with Fe which results in ilmenite flotation, and surface dissolution is beneficial to its oxidation, the floatability of ilmenite after surface dissolution is increased; meanwhile, sodium oleate interacts with Ca and Mg which results in titanangite flotation, and the quantities of Ca and Mg on the surface of titanautite are decreased due to the surface dissolution, so the floatability of titanaugite after surface dissolution is depressed. For an ilmenite ore obtained from Panzhihua with TiO2 grade of 8.41%, flotation after surface dissolution treatment could increase TiO2 grade of rough concentrate from 26.7% to 31.73 %.

Microwave assisted grinding of ilmenite ore

The influence of microwave heating on the grinding of Panzhihua ilmenite ore was investigated. Factors that influence the processing are： the microwave exposure time, power density and sample mass. 40 g sample was microwave heated for 30 s with 1 kW of microwave power and followed by water quenching. SEM analysis indicated that intergranular fractures occurred between ores and gangues other than transgranular fractures after microwave treatment, which would liberate minerals from each other effectively. The subsequently magnetic separation trials provided evidence that the recovery rate increased from 44% for raw ore to 72% by microwave treatment.

Effect of temperature on dielectric property and microwave heating behavior of low grade Panzhihua ilmenite ore

The permittivity of low grade Panzhuhua ilmenite ore at 2.45 GHz in the temperatures from 20 ℃ up to 100 ℃ was measured using the technology of open-ended coaxial sensor combined with theoretical computation. The results show that both the real （ε′） and imaginary （ε′） part of complex permittivity （ε′-jε′） of the ilmenite significantly increase with temperature. The loss tangent （tanδ） is a quadratic function of temperature, and the penetration depth of ilmenite decreases with temperature increase from 20 ℃to 100 ℃ The increase of the sample temperature under microwave radiation displays a nonlinear relationship between the temperature （T） and microwave heating time （t）. The positive feedback interaction between complex permittivity and sample temperature amplifies the interaction between ilmenite and the microwave radiation. The optimum dimensions for uniform heat deposition vary from 10 cm to 5 cm （about two power penetration depths） in a sample being irradiated from both sides in a 2.45 GHz microwave field when temperature increases from room temperature to 100 ℃

Effect of basicity on sintering behavior of low-titanium vanadium-titanium magnetite

Basicity has an important effect on the sinter quality, especially for low-titanium vanadium-titanium sinter. The effect of basieity on sintering behavior of low-titanium vanadium-titanium mixture, and the transference and distribution of element in sintering process were researched by sinter pot test, mineralogical analysis, scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS） analysis. The results show that CaO preferentially reacts with TiO2, generating pervoskite, so that the total liquid phase content of the sinter is low. There is an increase in the perovskite concentration of the sinter with the basicity ranging from 1.9：1 to 2.7：1. With increasing the basicity, the calcium ferrite content increases slightly and then rises rapidly, while the silicate content decreases and the metallurgical property of the sinter is improved. As for the distribution of these elements in the sinter, Ti occurs mainly in perovskite, V occurs mainly in silicate, and Fe occurs mainly in magnetite and hematite. The most abundant occurrence of Ca and Si occurs in silicate and perovskite. With increasing the basicity, the contents of A1 and Mg increase in calcium ferrite, while they decrease in other minerals.

Phase transitions, micro-morphology and its oxidation mechanism in oxidation of ilmenite (FeTiO_3) powder

Phase transitions, morphology changes, and oxidation mechanism of the ilmenite oxidation process were investigated. FeTi03 transforms to hematite and rutile when oxidation at 700-800 ℃, and pseudobrookite is formed when the oxidation temperature reaches 900 ℃. The initial ilmenite powder exhibits paramagnetism; however, after being oxidized at the intermediate temperature （800-850 ℃）, the oxidation product exhibits weak ferromagnetism. The oxidation mechanism was discussed. The microstructure observations show that a lot of micro-pores emerge on the surfaces of ilmenite particles at the intermediate temperature, which is deemed to be caoable ofenhancin~ the mass transfer ofoxgen during oxidation.

TiO_2 nanoparticles prepared by hydrochloric acid leaching of mechanically activated and carbothermic reduced ilmenite

A new combination method consisting of ball milling, carbothermic reduction and hydrochloric acid leaching was proposed for the preparation of nanosized synthetic rutile from natural ilmenite. The ball milling was employed to grind ilmenite into small particles. The carbothermic reduction was carried out to yield a high titanium slag, which would be easily purified by subsequent leaching procedure. Factors affecting the hydrochloric acid process, namely the leaching time, temperature, and acid concentration, were studied. After leaching and calcining the milled and annealed mixture of FeTiO3/C under the optimal conditions, the TiO2 nanoparticles with size of 10-200 nm and purity〉98.0% were obtained.

Solid-state reduction kinetics and mechanism of pre-oxidized vanadium-titanium magnetite concentrate

The solid-state reduction kinetics of pre-oxidized vanadium-titanium magnetite concentrate was studied. The phase and microstructure of the reduction product were characterized by XRD, SEM and EDS methods, based on which the mechanism of the solid-state reduction was investigated. The results showed that using coal as reductant at 950-1100 °C, the solid-state reduction of the pre-oxidized vanadium-titanium magnetite concentrate was controlled by interface chemical reaction and the apparent activation energy was 67.719 k J/mol. The mineral phase transformation during the reduction process can be described as follows： pre-oxidized vanadium-titanium magnetite concentrate → ulvospinel → ilmenite → Fe Ti2O5 →（FenTi1-n）Ti2O5. M3O5-type（M can be Fe, Ti, Mg, Mn, etc） solid solutions would be formed during the reduction process of the pre-oxidized vanadium-titanium magnetite concentrate at 1050 °C for 60 min. The poor reducibility of iron in M3O5 solid solutions is the main reason to limit the reduction property of pre-oxidized vanadium-titanium magnetite concentrate.

Effects of mechanical activation and oxidation-reduction on hydrochloric acid leaching of Panxi ilmenite concentration

The effects of oxidation-reduction treatment and mechanical activation on the hydrochloric acid leaching performance of Panxi ilmenite concentration were investigated.The results show that both of oxidation-reduction treatment and mechanical activation significantly accelerate the extraction of Fe,Ca and Mg from Panxi ilmenite concentration;however,the CaO and MgO contents of the calcined residues obtained from oxidized-reduced ilmenite concentration are higher than the standard values required by chlorination process.The Ca and Mg in oxidized-reduced ilmenite concentration can be leached much faster after mechanical activation,yielding a synthetic rutile which meets the requirements of chlorination process containing 90.50% TiO2 and 1.37% total iron as well as combined CaO and MgO of 1.00%.The optimum oxidation and reduction conditions are as follows：oxidization at 900 ℃ in the presence of oxygen for 15 min and reduction at 750 ℃ by hydrogen for 30 min.

Recovery of iron from waste ferrous sulphate by co-precipitation and magnetic separation

Magnetite concentrate was recovered from ferrous sulphate by co-precipitation and magnetic separation. In co-precipitation process, the effects of reaction conditions on iron recovery were studied, and the optimal reaction parameters are proposed as follows： n（CaO）/n（Fe2＋） 1.4：1, reaction temperature 80 ℃, ferrous ion concentration 0.4 mol/L, and the final mole ratio of Fe3＋ to FJ＋ in the reaction solution 1.9-2.1. In magnetic separation process, the effects of milling time and magnetic induction intensity on iron recovery were investigated. Wet milling played an important part in breaking the encapsulated magnetic phases. The results showed that the mixed product was wet-milled for 20 min before magnetic separation, the grade and recovery rate of iron in magnetite concentrate were increased from 51.41% and 84.15% to 62.05% and 85.35%, respectively.

Behaviors of vanadium and chromium in coal-based direct reduction of high-chromium vanadium-bearing titanomagnetite concentrates followed by magnetic separation

The reduction behaviors of FeO·V2O3 and FeO·Cr2O3 during coal-based direct reduction have a decisive impact on the efficient utilization of high-chromium vanadium-bearing titanomagnetite concentrates. The effects of molar ratio of C to Fe n(C)/n(Fe) and temperature on the behaviors of vanadium and chromium during direct reduction and magnetic separation were investigated. The reduced samples were characterized by X-ray diffraction(XRD), scanning election microscopy(SEM) and energy dispersive spectrometry(EDS) techniques. Experimental results indicate that the recoveries of vanadium and chromium rapidly increase from 10.0% and 9.6% to 45.3% and 74.3%, respectively, as the n(C)/n(Fe) increases from 0.8 to 1.4. At n(C)/n(Fe) of 0.8, the recoveries of vanadium and chromium are always lower than 10.0% in the whole temperature range of 1100-1250 °C. However, at n(C)/n(Fe) of 1.2, the recoveries of vanadium and chromium considerably increase from 17.8% and 33.8% to 42.4% and 76.0%, respectively, as the temperature increases from 1100 °C to 1250 °C. At n(C)/n(Fe) lower than 0.8, most of the FeO·V2O3 and FeO·Cr2O3 are not reduced to carbides because of the lack of carbonaceous reductants, and the temperature has little effect on the reduction behaviors of FeO·V2O3 and FeO·Cr2O3, resulting in very low recoveries of vanadium and chromium during magnetic separation. However, at higher n(C)/n(Fe), the reduction rates of FeO·V2O3 and FeO·Cr2O3 increase significatly because of the excess amount of carbonaceous reductants. Moreover, higher temperatures largely induce the reduction of FeO·V2O3 and FeO·Cr2O3 to carbides. The newly formed carbides are then dissolved in the γ(FCC) phase, and recovered accompanied with the metallic iron during magnetic separation.

Reductive kinetics of Panzhihua ilmenite with hydrogen

The hydrogen reduction of Panzhihua ilmenite concentrate in the temperature range of 900?1050 °C was systematicallyinvestigated by thermogravimetric analysis (TG), X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. It wasshown that the products of the Panzhihua ilmenite reduced at 900 °C were metallic iron and rutile. Above 1000 °C, ferrouspseudobrookite solid solution was generated. During the reduction process, element Mg gradually concentrated to form Mg-rich zonewhich can influence the metallization process. The reduction reaction proceeded topochemically and its related reduction kineticswere also discussed. The kinetics of the reduction indicated that the rate-controlling step was the diffusion process. The apparentactivation energy of the hydrogen reduction of Panzhihua ilmenite was calculated to be 117.56 kJ/mol, which was larger than that ofsynthetic ilmenite under the same reduction condition.

Behavior of vanadium during reduction and smelting of vanadium titanomagnetite metallized pellets

The effects of CaO content,MgO content and smelting temperature on the vanadium behavior during the smelting of vanadium titanomagnetite metallized pellets were investigated.The thermodynamics of reduction and distribution of vanadium was analyzed and the high-temperature smelting experiments were carried out.The thermodynamic calculations show that the distribution ratio of vanadium between the slag and the hot metal decreases with the increments of CaO and MgO content in the slag as well as the increase of the smelting temperature.The smelting experiments demonstrate that the vanadium content in iron and the recovery rate of vanadium in pig iron increase as the CaO content,MgO content and smelting temperature increase,whereas the vanadium distribution ratio between the slag and iron tends to decrease.Moreover,the recovery rate of vanadium in pig iron has a rising trend with increasing the optical basicity of the slag.The addition of MgO in the slag to increase the slag optical basicity can not only improve the vanadium reduction but also promote the formation of magnesium-containing anosovite,which is beneficial to following titanium extraction.