莫托沙拉赤铁矿反浮选工艺的研究

莫托沙拉矿以赤铁矿为主。根据矿样的岩相分析、多元素化学分析、物相分析、粒度分析及磁性分析结果，对莫托沙拉铁矿进行了阴离子反浮选和阳离子反浮选的可选性研究，讨论了温度、捕收剂和抑制剂种类及用量等因素对反浮选效果的影响。试验结果表明， 25 ℃时采用阴离子反浮选工艺处理莫托沙拉矿能取得铁品位60.15%、铁回收率93.23%、SiO₂含量9.32%的铁精矿。     

水的磁化处理对赤铁矿可浮性影响的正交试验研究

基于L(81)（3(40)）正交设计试验，论文详细研究了水的磁化处理中的四个磁场因素：磁场强度、介质流速、磁化时间和磁场位型的变化对赤铁矿可浮性的影响及显著性。试验结果表明水的磁化处理对赤铁矿的浮选上浮率存在显著性影响，并且磁场因素之间存在显著的交互作用。     

磁种对赤铁矿铁矿石脱泥工艺的影响

在选择性絮凝分选过程中加入磁种，以增加絮团的磁化率，达到用磁选或磁选、重选联合方法分离絮团的目的。根据磁种在选择性絮凝－脱泥工艺分选赤铁矿中的作用试验结果，论述磁种用量、粒度对该工艺指标的影响。     

One-step synthesis of hematite (α-Fe2O3) nano-particles by direct thermal-decomposition of maghemite

In this research work, α-Fe₂O₃ nano-particles were prepared by direct thermal-decomposition of γ-Fe₂O₃. Precursor powders (γ-Fe₂O₃) were synthesized by wet chemical method at room temperature and then, the precursors were subsequently calcined in air for 1 h at 500 °C. Samples were characterized by thermal gravimetric analysis (TGA), X-ray diffraction (XRD), energy dispersive spectra (EDS), infrared spectrum (IR) and transmission electron microscopy (TEM), respectively. The XRD, EDS, and IR results indicated that the synthesized α-Fe₂O₃ particles were pure. The TEM image showed that the α-Fe₂O₃ nano-particles were spherical and 18 ± 2 nm in size. Magnetic properties have been detected by a vibrating sample magnetometer (VSM) at room temperature. The γ-Fe₂O₃ and α-Fe₂O₃ nano-particles exhibited a super-paramagnetic and weak ferromagnetic behavior at room temperature, respectively. Using the present method, hematite nano-particles can be produced without expensive organic solvent and complicated equipment.     

Anomalous conductivity-type transition sensing behaviors of n-type porous α-Fe2O3 nanostructures toward H2S

Porous urchin-like α-Fe₂O₃ nanostructures with n-type semiconducting properties were used as gas sensing materials. Interestingly, it was observed abnormal n-p transition sensing behavior induced by the variation of working temperature and p-n transition sensing behavior related to the increase of H₂S concentration. Large density of unstable surface states resulting from high surface-to-volume ratio would be beneficial for the formation of a surface inversion layer and account for the n-p transition. Furthermore, the as-prepared sensor showed good H₂S sensing performances with short response/recovery time within 5/10 s, and relatively low detection limit of 1 ppm. These results help us to understand the sensing mechanism of α-Fe₂O₃ and hint the potential application of the as-prepared sensor in monitoring H₂S.     

Characterization of structured α-Fe2O3 photoanodes prepared via electrodeposition and thermal oxidation of iron

In this paper we explore the feasibility of using electrodeposition as a low-cost, versatile and easily upscalable technique for preparing α-Fe₂O₃ (hematite) photoanodes for water splitting applications. The photoelectrodes are prepared on transparent conducting glass substrates by electrodeposition of Fe, using a non-aqueous precursor solution at room temperature, followed by thermal oxidation in air. Variations in deposition parameters yield films with diverse morphologies. The effects of the different morphologies on the structural, optical, and photoelectrochemical properties are investigated by photocurrent measurements under AM1.5 illumination. The photocurrent could be improved by growing the first part of the Fe film at low current densities, yielding a dense underlayer, followed by the deposition of a more structured, porous film at high current densities. X-ray diffraction reveals that high deposition currents result in smaller crystallites and a (110) preferred orientation. This orientation is favorable when using hematite as a photoanode, since the conductivity in the [110] direction is known to be up to four orders of magnitude higher than in directions perpendicular to this.     

印度某赤铁矿洗矿溢流选矿试验

为了给铁品位在50%左右的印度某赤铁矿洗矿溢流的利用提供依据,采用细筛-强磁选-阴离子反浮选流程和细筛-螺旋溜槽-强磁选-阴离子反浮选流程对该洗矿溢流进行了选矿试验。试验结果表明,在-0.076 mm占75%的磨矿细度下,两流程分别可取得精矿铁品位为67.01%,回收率为87.77%和精矿铁品位为67.12%,回收率为89.71%的选别指标。鉴于后一流程可比前一流程减少约1/3的浮选量,因此推荐采用后一流程。     

碱度和内配燃料对赤铁矿球团强度的影响

针对赤铁矿球团强度低的问题,以巴西某赤铁矿精矿为对象,研究了碱度、内配燃料以及它们的相互作用对赤铁矿球团强度的影响。结果表明：制备含镁熔剂性赤铁矿球团时,将碱度控制在0.3~1.2可显著提高预热球团和焙烧球团的抗压强度;制备内配燃料酸性含镁赤铁矿球团时,焦粉配比不超过1.0%可改善预热球团强度而基本不影响焙烧球团强度;制备内配燃料熔剂性含镁赤铁矿球团时,将焦粉配比控制1.5%以内,球团碱度控制在0.9,可显著提高焙烧球团强度。由此可见,制备内配燃料熔剂性含镁球团是改善赤铁矿球团强度的有效途径。     

水玻璃溶液化学与萤石,赤铁矿浮选分离机理研究

本文通过浮选试验、ζ-电位和吸附测定,研究了水玻璃对萤石、赤铁矿浮选分离的作用机理。结果表明,水玻璃在溶液中的溶解度和离子组成与溶液浓度、pH值和硅钠比有关;在pH6—9时,赤铁矿、萤石对水玻璃各种离子的吸附活性不同,从而实现两种矿物的分离。     

Adsorption of rotavirus and bacteriophage MS2 using glass fiber coated with hematite nanoparticles

Batch and flow-through experiments were conducted to investigate the removal and inactivation of rotavirus (RV) and bacteriophage MS2 using glass fiber coated with hematite nanoparticles. Batch tests showed a high removal of MS2 (2.49 × 10¹¹ plaque forming unit/g) and RV (8.9 × 10⁶ focal forming unit/g) at a low concentration of hematite nanoparticles in solution (0.043 g/L and 0.26 g/L, respectively). Virus adsorption was, however, decreased in the presence of bicarbonate ions and natural organic matter (NOM) in solution, suggesting a great affinity of iron oxide nanoparticles for these competitors. Adsorption on hematite nanoparticles by MS2 and RV was also tested with aquifer groundwater under saturated flow conditions to mimic environmental conditions with promising results (8 × 10⁸ plaque forming unit/g and 3 × 10⁴ focal forming unit/g, respectively). Desorption of up to 63% of infectious MS2 and only 2% of infectious RV from hematite nanoparticles were achieved when an eluant solution containing beef extract and glycine was used. Transmission electron microscopy (TEM) images showed evidence of electrostatic adsorption of apparently intact MS2 and structurally damaged RV particles to hematite nanoparticles. Results from this research suggest that a cartridge made of glass fiber coated with hematite nanoparticles could be used as a point-of-use device for virus removal for drinking water treatment.