不同还原方法对赤铁矿粉金属化率的影响

对粒径40～160 μm的赤铁矿粉进行直接还原的实验研究,利用H2作为还原气体在竖直管式炉中流态化焙烧还原,利用固体C在马弗炉中静态堆积原位焙烧还原.结果表明,随着赤铁矿粉粒径变小、反应温度提高、反应时间增加、还原气体流量增大,赤铁矿还原速率增大,金属化率明显提高.以H2作为还原气体反应30 min,金属化率可达94.60％.煤基堆积静态直接还原赤铁矿粉,以同心圆布料,1100℃下还原3.5h,金属化率达到96.85％.     

Preparation and electrochemical performance of flower-like hematite for lithium-ion batteries

Flower-like hematite (α-Fe₂O₃) has been successfully prepared by heat-treatment from the iron(III)-oxyhydroxide precursor, which is obtained by the hydrolysis of FeCl₃ solution in the presence of NaClO. In this process, no templates or catalysts are required. SEM and TEM characterizations confirm that micro-flowers are composed of several dozen self-assembled nanopetals with the thickness of about 20 nm. On the basis of the morphology investigations in time-dependent experiments, the possible growth mechanism of the flower-like α-Fe₂O₃ is proposed, which is similar to a two-stage growth process. Furthermore, as an anode electrode material for rechargeable lithium-ion batteries, the flower-like α-Fe₂O₃ exhibits excellent electrochemical performance, which can be attributed to the high surface area induced by the flower-like structure, the short lithium diffusion length and the restriction of volume change of the Li⁺ insertion/extraction.     

Sn self-doped α-Fe2O3 nanobranch arrays supported on a transparent,conductive SnO2 trunk to improve photoelectrochemical water oxidation

We produced hierarchically branched Fe₂O₃ nanorods on a Sb:SnO₂ transparent conducting oxide (TCO) nanobelt structure as photoanodes for photoelectrochemical water splitting. Single-crystalline SnO₂ nanobelts (NBs) surrounded by Fe₂O₃ nanorods (NRs) were synthesized by thermal evaporation, then underwent chemical bath deposition and annealing. When Fe₂O₃ was crystallized by annealing, Sn was diffused from SnO₂ NBs and incorporated to Fe₂O₃ NRs, which was confirmed through Energy dispersive spectroscopy. Unlike previous high temperature sintering (∼800 °C), Sn doped hematite NRs were obtained at a low temperature (∼650 °C). This occurred since SnO₂ NBs directly connected to Fe₂O₃ NRs are an abundant source of Sn dopant. The 3D hematite NRs on SnO₂ NBs annealed at 650 °C produce a photocurrent density of 0.88 mA/cm² at 1.23 V vs. RHE, which is 3 times higher than that of hematite NRs on a fluorine doped tin oxide (FTO) glass substrate annealed at the same temperature. The enhanced photocurrent is attributed to the improved electrical conductivity of Fe₂O₃ NRs by Sn doping, the efficient electron transport pathway by TCO nanowire and the increased surface area by hierarchically branched structure.     

云南某微细粒嵌布赤铁矿选矿工艺研究

云南某赤铁矿矿石中铁矿物嵌布粒度微细,生产上采用磁选、重选工艺,只能获得铁品位为57%左右的铁精矿,不能满足铁精矿品位大于62%的球团生产要求。为此,对该矿石进行了提高精矿品位的选矿试验。试验采用阶段磨矿-阶段强磁选-反浮选联合工艺流程,在-0.038 mm占86%的最终磨矿细度下,获得了铁品位为62.20%,铁回收率为56.36%的铁精矿。     

SLon型高梯度磁选机回收微细粒氧化铁矿工艺研究

以满银沟铁矿选矿厂的浓密箱给矿、浓密箱沉砂和浓密箱溢流为研究对象,采用改变扫选SLon型高梯度磁选机磁介质大小的方法,对这3种铁矿石进行试验研究,以达到降低尾矿品位,提高该铁矿石回收率的目的。     

SH—A新型高效铁矿石浮选药剂的研究

SH－A捕收剂为一种磺酸金属盐和助剂的调和物,可直接用于不脱泥碱性正浮选流程。用该捕收剂对普通赤铁矿、高亚铁难选矿进行了试验。结果表明,该药剂选别普通赤铁矿、高亚铁难选矿分别获得了铁精矿品位65．80％和62．33％、回收率78．06％和80．48％的良好指标。     

氟硅酸铵在赤铁矿与霓石分离中的作用机理

研究了以油酸钠为捕收剂浮选赤铁矿时,氟硅酸铵对含铁硅酸盐脉石矿物霓石的选择性抑制作用。纯矿物浮选试验结果表明,在pH4～5的弱酸性条件下,氟硅酸铵对赤铁矿浮选的影响较小,而对霓石强烈抑制,从而能够实现两种矿物的浮选分离。通过红外光谱(IR)与光电子能谱(XPS)分析测试,发现(NH4)2SiF6在霓石矿物表面以化学吸附作用为主,并提出了SiF6^2-在两种矿物表面的理论吸附模型,首次运用配位化学的观点合理解释了氟硅酸铵选择性抑制含铁硅酸盐矿物的根本原因。     

上厂铁矿尾矿回收赤铁矿的试验和应用

介绍了昆钢上厂铁矿尾矿性质 ,采用SLon 1 5 0 0立环脉动高梯度磁选机回收尾矿中铁矿物的小型试验和工业试验情况 ,阐述了该工艺的选别特点、技术指标及投产后可取得的经济效益和社会效益。     

Using computational approaches to model hematite surfaces

Oxide surfaces are very important in many areas of science and technology. The development of both new experimental surface techniques and theoretical approaches, has allowed a better understanding of metal oxide surfaces. In this work, a forcefield-based method is applied to the calculation of some properties of the -Fe₂O₃(0 0 1) and (0 1 2) surfaces, with the aim to obtain equilibrium structures (relaxed atomic positions of surface atoms) and some data on the energetics of the adsorption of H₂O and SO₂ molecules on these surfaces.     

“提铁降杂”选矿工艺技术研究与生产实践

介绍了鞍钢矿业推动"提铁降杂"新的学术思想,以及鞍山贫赤(磁)铁矿选矿新工艺、新药剂与新设备研究及工业应用,使鞍山式铁矿石的选矿技术取得重大突破,选矿装备、技术指标达到国际领先水平,为我国贫铁矿产资源高效开发利用和提升国产铁精矿的国际竞争力,提供了技术支撑和成功范例。