复配阴离子捕收剂在高磷鲕状赤铁矿反浮选中的应用

对鄂西某高磷鲕状赤铁矿进行了反浮选试验研究。采用复配阴离子捕收剂915BM,通过条件试验,确定最佳浮选工艺条件为:矿浆温度25 ℃,粗选pH值为11、淀粉用量1 000 g/t、氧化钙用量500 g/t、915BM用量600 g/t,精选915BM用量200 g/t。一粗二精一扫闭路试验得到的精矿铁品位55.90%、回收率80.73%,磷含量降到0.23%。对浮选精矿、尾矿和中矿进行分析,结果表明,磷在+0.044 mm粒级中分布率相对较高,要进一步降低产品中磷含量,必须增加磨矿细度。     

草分枝杆菌与赤铁矿和石英间的作用力分析

草分枝杆菌、赤铁矿、石英具有不同的表面电件,因而具有不同的相互作用力。测定了这3种物质的Zeta电位,利用DLVO理论计算和分析了草分枝杆菌与赤铁矿、草分枝杆菌与石英之间的作用力,并绘制了总作用势能、范德华力势能、静电势能与物质间距之间的关系曲线。分析表明：在pH=5条件下,草分枝杆菌与赤铁矿之间的总作用力始终表现为吸引力,且吸引力随着间距的减小而增大,当间距小于250A后,吸引力迅速增大;而草分枝杆菌与石英之间的总作用力表现为排斥力,且排斥力随着间距的减小而增大,当间距小于250A后,排斥力迅速增大。因此,草分枝杆菌可在几乎没有任何斥力的情况下,迅速吸附在赤铁矿表面,而很难吸附在石英表面。利用草分枝杆菌与赤铁矿、石英吸附能力的差异,可将草分枝杆菌作为赤铁矿、石英分离时赤铁矿的絮凝-捕收剂使用。     

巴尔布拉乌赤铁矿选矿工艺扩大试验研究

通过对哈萨克斯坦巴尔布拉乌微细粒嵌布难选赤铁矿选矿工艺研究,最终开发出强磁-反浮选微细粒嵌布赤铁矿选矿工艺。并进行了选矿工艺扩大试验,采用强磁预先抛尾,而后再磨应用高效的调整剂CN及高效复合捕收剂BK959,经一次粗选、三次扫选、三次精选的反浮选流程,有效实现难选赤铁矿的浮选分离,得到了高品位的赤铁矿精矿,铁精矿品位达到66%以上、回收率达到70%以上。为该矿的工业开发提供了选矿技术依据。     

某赤铁矿浮-磁工艺流程试验研究

对某赤铁矿的浮选工艺进行了系统试验研究,得到了浮选最佳药剂条件,浮选铁精矿品位为62.50%,铁的回收率为65.64%,浮选尾矿用弱磁选机磁选还可取得铁品位61.09%、铁回收率6.72%的磁选精矿。最终铁的总回收率为72.36%,铁精矿品位为62.33%。     

C5—9羟肟酸浮选赤铁矿

应用热力学,动力学理论分析了由羟胺与羧酸衍生物反应合成羟肟酸的各合成路线,采用最佳路线－酰氯羟胺化法合成Ｃ５－９羟肟酸,用于浮选内蒙古乌海地区某铁矿的地表氧化矿中的细粒赤铁矿,小型粗选试验表明,用该法合成的Ｃ５－９羟肟酸对赤铁矿的选别能力优于新特２号,石油磺酸钠,水杨羟肟酸以及用酯化法生产有Ｃ５－９羟肟酸等捕收剂。／     

Understanding the Role of Underlayers and Overlayers in Thin Film Hematite Photoanodes

Recent research on photoanodes for photoelectrochemical water splitting has introduced the concept of under‐ and overlayers for the activation of ultrathin hematite films. Their effects on the photocatalytic behavior were clearly shown; however, the mechanism is thus far not fully understood. Herein, the contribution of each layer is analyzed by means of electrochemical impedance spectroscopy, with the aim of obtaining a general understanding of surface and interface modifications and their influence on the hematite photoanode performance. This study shows that doping of the hematite from the underlayer and surface passivation from annealing treatments and an overlayer are key parameters to consider for the design of more efficient iron oxide electrodes. Understanding the contribution of these layers, a new design for ultrathin hematite films employing a combination of a gallium oxide overlayer with thin niobium oxide and silicon oxide underlayers is shown to achieve a photocurrent onset potential for the photoelectrochemical oxidation of water more negative than 750 mV versus the reversible hydrogen electrode (RHE) at pH 13.6, utilizing Co‐Pi as a water oxidation catalyst. It is demonstrated that multilayer hematite thin film photoanodes are a strategy to reduce the overpotential for this material, thereby facilitating more efficient tandem cells.     

Photosystem I‐based Biophotovoltaics on Nanostructured Hematite

The electronic coupling between a robust red algal photosystem I (PSI) associated with its light harvesting antenna (LHCI) and nanocrystalline n‐type semiconductors, TiO₂ and hematite (α‐Fe₂O₃) is utilized for fabrication of the biohybrid dye‐sensitized solar cells (DSSC). PSI‐LHCI is immobilized as a structured multilayer over both semiconductors organized as highly ordered nanocrystalline arrays, as evidenced by FE‐SEM and XRD spectroscopy. Of all the biohybrid DSSCs examined, α‐Fe₂O₃/PSI‐LHCI biophotoanode operates at a highest quantum efficiency and generates the largest open circuit photo­current compared to the tandem system based on TiO₂/PSI‐LHCI material. This is accomplished by immobilization of the PSI‐LHCI complex with its reducing side towards the hematite surface and nanostructuring of the PSI‐LHCI multilayer in which the subsequent layers of this complex are organized in the head‐to‐tail orientation. The biohybrid PSI‐LHCI‐DSSC is capable of sustained photoelectrochemical H₂ production upon illumination with visible light above 590 nm. Although the solar conversion efficiency of the PSI‐LHCI/hematite DSSC is currently below a practical use, the system provides a blueprint for a genuinely green solar cell that can be used for molecular hydrogen production at a rate of 744 μmoles H₂ mg Chl^?1 h^?1, placing it amongst the best performing biohybrid solar‐to‐fuel nanodevices.     

国外某高磷硅鲕状铁矿选矿工艺研究

针对国外某高磷硅鲕状铁矿进行了选矿工艺研究。通过矿石性质分析查明了该矿难选的原因,并确定了阶段磨矿-弱磁选-反浮选脱磷硅联合选矿工艺流程。结果表明,采用推荐工艺,可获得Fe品位65.68%的磁铁矿和Fe品位55.58%的赤铁矿,总回收率达到78.92%。     

Low-Spin-State Hematite with Superior Adsorption of Anionic Contaminations for Water Purification

Hematite attracts intensive interest as an adsorbent for water purification, but the oversized dimension and inherent high-spin Fe(III) restrict its adsorption capability and kinetics. Herein a spatial-confinement strategy is reported that synthesizes ultrafine α-Fe₂O₃ benefiting from nanogrids constructed by predeposition of TiO₂ nanodots in the MCM-41 channel, and that tunes the spin-state of Fe(III) from high-spin to low-spin induced by the strong guest–host interaction between the ultrafine Fe₂O₃ with SiO₂ (MCM-41). The low-spin Fe(III) endorses strong bonding with anionic adsorbates, and significantly facilitates the electrons transfer from Fe₂O₃ to SiO₂ to form a highly positive charged surface, and thereby shows superior electrostatic multilayer adsorption performance to different kinds of anionic contaminations. Specifically, the maximum uptake, adsorption rate, and distribution coefficient (K_d) for Rose Bengal dye reach as high as 1810 mg g⁻¹, 1644 g (g min)⁻¹, and 2.2 × 10⁶ L kg⁻¹, which are more than 8, 230, and 3700 times higher than those of commercial activated carbon, respectively. It also shows outstanding purification performance for real field water. It is demonstrated that a strong guest–host interaction can alter the spin-state of transition metal oxides, which may pave a new way to improve their performance in adsorption and other applications like catalysis.     

姑山赤铁精矿强磁选-阴离子反浮选提铁降硅试验

姑山赤铁矿选矿厂磨选流程采用阶段磨矿-单一高梯度强磁选工艺流程,铁精矿TFe品位一直保持在约57%,SiO2含量约12%。为进一步提高产品质量,对姑山赤铁精矿进行了磨矿-强磁选-阴离子反浮选试验。试验结果表明：磨矿细度-30 μm含量占90%,强磁选一粗一扫磁场强度0.8、0.95 T,阴离子反浮选在NaOH用量1 000 g/t、淀粉用量1 000 g/t、石灰用量600 g/t、捕收剂RA915用量750+250 g/t的条件下,经过一粗一精三扫反浮选闭路试验流程,浮选铁精矿TFe品位可达63.25%,回收率70.15%,说明该工艺对姑山赤铁精矿提铁降硅技术上可行。试验结果可为现场工艺优化提供参考。