从磁矿石中拣出铁块的高阻抗传感器

本文介绍了一种安装在运输皮带上的除铁传感器，该传感器能从磁矿石中拣铁块，不仅耗能小，而且灵敏度和可靠性很高。文中比较详细地介绍了这种传感器的设计和制作方法，着重阐明了能从磁矿石中拣出铁块的原理。

一种难选铁矿石磁选精矿的浮选新工艺研究

为了更好地解决含碳酸盐铁矿石磁选精矿的浮选问题,进行了添加分散剂的直接反浮选新工艺试验研究。研究结果表明,添加分散剂可以削弱碳酸铁对反浮选带来的不利影响,获得品位为66.26%、回收率为70.23%的铁精矿,流程结构较为简单。

某中细粒嵌布贫赤磁混合铁矿石的节能分选工艺研究

某高硅低硫磷赤磁混合铁矿石铁品位27.72%,主要铁矿物是赤(褐)铁矿,其次为磁铁矿、半假象赤铁矿,铁矿物呈不均匀中细粒嵌布。为确定该矿石的节能分选工艺,采用阶段磨矿阶段弱磁选+强磁选、淘洗机精选、常温(20℃)反浮选流程进行选矿试验。结果表明,原矿在一段磨矿细度-0.075 mm55%、二段磨矿细度-0.045 mm80%条件下,可获得品位65.02%、回收率22.89%的淘洗精矿,品位65.81%、回收率46.37%的反浮选精矿,最终精矿产率29.29%、品位65.55%、回收率69.26%,尾矿品位12.05%。试验确定的流程简单、能耗低、环境污染小、选别指标好,实现了节能降耗流程设计要求,具有很高的实际生产应用价值。

磁海矿石性质与选矿工艺研究探讨

针对磁海铁矿石贫、细、杂、难磨难选的特点,分析了原生产流程选矿指标低的原因,提出了选矿工艺流程的改进依据和建议,改造后的选矿工艺流程更符合磁海铁矿石性质,选矿指标显著提高。

CS-2型粗粒湿式电磁感应辊强磁选机的研制及生产使用

入选粒度上限为15mm的CS-2型粗粒湿式电磁感应辊强磁选机研制与应用,为国内外用湿式强磁选方法选别粗颗粒弱磁性矿石开辟了新途径。该机机重16t,单机处理量达25～30t/h,磁场强度可在320～2424kA/m(4000～17800奥)之间调节,文章还就有关感应辊强磁选机某些参数设计计算提出了一些见解。

硫化铜矿中铁有缺失的伴生磁黄铁矿的综合回收

一、矿石性质研究某硫化铜矿,主要铜矿物为黄铜矿,其次为斑铜矿。主要伴生矿物为磁黄铁矿,其次为黄铁矿、铁闪锌矿。主要脉石矿物为石英,其次为白云母、绢云母、黑云母、绿泥石和阳起石。化学多项分析结果见表1。

磁黄铁矿石促进好氧颗粒污泥形成的效果与机制

为探究天然磁黄铁矿石对好氧颗粒污泥(AGS)处理染料废水过程中颗粒化进程的影响,在室温条件下运行4个序批式反应器(SBR),通过改变进水有机负荷和碳源,研究了颗粒化过程中AGS的SVI、粒径及Zeta电位的变化,并通过三维荧光光谱(3D-EEM)分析AGS成分以及磁黄铁矿石界面能变化来解析AGS的形成机制。结果表明,投加磁黄铁矿石约20 d就形成了AGS。高有机负荷及采用乙酸钠(NaAc)作为碳源时,SVI平均值由初始的105 mL/g下降到运行末期的(25.99±4.57) mL/g。3D-EEM分析显示,投加磁黄铁矿石能够增加污泥疏水性蛋白质的含量,促进AGS形成。颗粒化过程中,矿石液固界面黏附功逐渐降低,而界面能上升,也促进了AGS的形成。

Enhancement of pentlandite surface magnetism and implications for its separation from serpentine via magnetic separation

The magnetism of pentlandite surface was enhanced through the selective precipitation of micro-fine magnetite fractions on pentlandite surfaces. This was achieved through adjustment of slurry pH and addition of surfactants. The results showed that at pH 8.8 with the addition of 100 g/t sodium hexametaphosphate, 4.5 L/t oleic acid, and 4.5 L/t kerosene, significant amount of fine magnetite particles adhered to the pentlandite surface, while trace amount of coating was found on serpentine surfaces. Thus, the magnetism of pentlandite was enhanced and pentlandite was well separated from serpentine by magnetic separation under the magnetic field intensity of 200 kA/m. Scanning electron microscopy （SEM） and zeta potential measurement were performed to characterize changes of mineral surface properties. Calculations of the extended Derjaguin-Landau-Verwey-Ocerbeek （EDLVO） theory indicated that, in the presence of surfactants the total interaction energy between magnetite and pentlandite became stronger than that between magnetite and serpentine. This enabled the selective adhesion of magnetite particles to pentlandite surfaces, thereby enhancing its magnetism.

Recovering limonite from Australia iron ores by flocculation-high intensity magnetic separation

Successful recovery of limonite from iron fines was achieved by using flocculation-high intensity magnetic separation （FIMS） and adding hydrolyzed and causticized flocculants according to the characteristic of iron fines. The separation results of the three iron samples are as follows： iron grade 66.77%- 67.98% and the recovery of iron 69.26%-70.70% by the FIMS process with flocculants. The comparative results show that under the same separation conditions the F1MS process can effectively increase the recovery of iron by 10. 97%- 15.73%. The flowsheet results confirm the reliability of the process in a SHP high intensity magnetic separator. The concentrate product can he used as raw materials for direct reduction iron-smelting. The hydrolyzed and causticized flocculants can selectively flocculate fine feebly-magnetic iron mineral particles to increase their apparent separation sizes. The larger the separation size, the stronger the magnetic force. By comparing the separation results of the three samples it is found that among the three samples the higher the limonite content, the better the separation result. This means that the separation result relates closely to the flocculation process and the adding pattern of the flocculant.

Magnetic separation studies for a low grade siliceous iron ore sample

Investigations were carried out, on a low grade siliceous iron ore sample by magnetic separation, to establish its amenability for physical beneficiation. Mineralogical studies revealed that the sample consists of magnetite, hematite and goethite as major opaque oxide minerals where as silicates as well as carbonates form the gangue minerals in the sample. Processes involving combination of classification, dry magnetic separation and wet magnetic separation were carried out to upgrade the low grade siliceous iron ore sample to make it suitable as a marketable product. The sample was first ground and each closed size sieve fractions were subjected to dry magnetic separation and it was observed that limited upgradation is possible. The ground sample was subjected to different finer sizes and separated by wet low intensity magnetic separator. It was possible to obtain a magnetic concentrate of 67% Fe by recovering 90% of iron values at below 200 lm size.

Trace element composition of magnetite from the Xinqiao Fe–S(–Cu–Au) deposit, Tongling, Eastern China: constraints on fluid evolution and ore genesis

The Xinqiao deposit is one of several polymetallic deposits in the Tongling ore district. There are two types of mineralization in the Xinqiao： skarn-type and stratiform-type. The skarn-type mineralization is characterized by iron oxides such as magnetite and hematite, whereas stratiform-type mineralization is characterized by massive sulfides with small amounts of magnetite and hematite. We defined three types of ores within the strati- form-type mineralization by the mineral assemblages and ore structures. Type Ⅰ ore is represented by magnetite crosscut by minor calcite veins. Type Ⅱ is a network ore composed of magnetite and crosscutting pyrite. Type Ⅲ is a massive ore containing calcite and hematite. Type Ⅰ magnetite is characterized by highly variable trace element content, whereas Type Ⅱ magnetite has consistently higher Si, Ti, V, and Nb. Type Ⅲ magnetite contains more In, Sn, and As than the other two types. Fluid-rock interaction, oxygen fugacity （fO2）, and temperature （T） are the main factors controlling element variation between the different magnetite types. Type I magnetite was formed by more extensive fluid-rock interaction than the other two types at moderate fO2 and T conditions. Type Ⅱ magnetite is thought to have formed in relatively low fO2 and high-Tenvironments, and Type Ⅲ in relatively high fOe and moderate-T environments. Ca ＋ Al ＋ Mn and Ti ＋ V discrimination diagrams show that magnetite in the Xin qiao deposit is hydrothermal in origin and is possibly linked with skarn.

Characterization and technology of fast reducing roasting for fine iron materials

The features of the techniques of fast reducing roasting （FRR） and conventional magnetic roasting, as well as tremendous demands of iron ores in iron and steel industry of China, were briefly described. The test equipment suitable for FRR of fine-grained materials was introduced. Weakly magnetic materials with grain size of 〈0.30 mm were converted into strongly magnetic materials by FRR for several to dozens of seconds. In a weakly reducing atmosphere and at 740-800 ~C, refractory powder iron material （〈0.30 mm） which is rich in specularite, limonite and Mg-Mn siderite was subjected to FRR for a few seconds to 60 s. Concentrate with iron grade of 55.67%-55.21%, high contents of Mg and Mn in the ore is obtained and the yield of magnetic separation reaches 81.66%-86.57%. The results of X-ray diffraction （XRD） analysis and magnetism detection of the material before and after FRR indicate that weakly magnetic material is mainly converted into strongly magnetic material Fe304 with specific saturation magnetic moment. The efficiency of FRR is consistent with TFe recovery of magnetic separation; meantime, the specific sa^u＇ation magnetic moment increases from 33 to 42 times after FRR. Calculations show that speeds of flash magnetic roasting are obtained from several dozen to two or three hundred times, compared with rotary kiln or shaft furnace. This indicates that it is practicable to use the fast reducing roasting technique to improve the comprehensive utilization of iron ore resources.

Characterization and processing of talc-magnesite from the Zinelbulak deposit

The characteristics of talc-magnesite from the Zinelbulak deposit(Uzbekistan) were investigated via X-ray diffraction, differential thermal analysis,infrared spectroscopy and optical microscopy.The mineralogical composition of the Zinelbulak talc-magnesite consists of 52 wt.%talc,43 wt.%carbonates and 5 wt.%of the iron-containing minerals magnetite,siderite and chlorite.Petrographic analysis confirmed the presence of carbonates in two forms:magnesite and breunnerite.Grindability tests revealed that talc and magnesite particles are completely separated after a grinding process carried out for 10～12 min.The distribution of the yield of talc and magnesite,as a function of the particle size,shows an irregular feature in that a comparatively coarser sample(>0.1 mm) is richer in magnesite and poor in talc while a comparatively finer sample(<0.1 mm) has a composition poorer in magnesite.The dressability of the Zinelbulak talc-magnesite was tested using conventional gravity concentration,flotation and electromagnetic separation.Gravity concentration was found to be the most economic initial process for the complete separation of magnesium carbonate and talc.Subsequent flotation and magnetic separation techniques could further increase the yield of high quality magnesite and talc.Refractory samples prepared by heating the separated magnesite at 1600℃for 2 h met the State Standards for refractory materials.

Mineralogy, liberation and leaching characteristics of iron oxide phases in an Indian diaspore sample

The removal of iron from an Indian diaspore sample was studied using magnetic separation and leaching techniques aided by an in-depth mineralogical characterization study involving quantitative mineralogical evaluation by scanning electron microscope（QEMSCAN）, electron probe micro-analyzer（EPMA） and X-ray diffraction（XRD）. The characterization studies indicate that extremely fine-sized hematite grains are associated with several other mineral phases in a complex manner with around 60% of the hematite not liberated even below the size of 38 μm limiting the scope of physical separation processes to remove the iron. Wet high intensity magnetic separation（WHIMS） studies reveal that only 49% of iron can be removed. Further, leaching studies using oxalic acid suggest that around 76% of the iron can be removed under conditions such as a solid to liquid ratio of 0.05：1, a temperature of 90 ℃ a time period of 120 min and an acid concentration of 1 mol/L. The dissolution of iron in oxalic acid is found to be controlled by chemical reaction and the activation energy is calculated as 35.15 k J/mol.

Appropriate titanium slag composition during smelting of vanadium titanomagnetite metallized pellets

The suitable titanium slag composition with high titanium content for electric furnace smelting of vanadium titanomagnetite was investigated through thermodynamics and related phase diagram analysis.According to the thermodynamic results,low-melting-point regions and MgTi2O5primary phase area in the phase diagrams,the suggested titanium slag composition for the present vanadium titanomagnetite metallized pellets should consist of50%TiO2,8%-12%MgO and13%Al2O3(mass fraction)with a binary basicity of0.8-1.2.Finally,the verified smelting experiments were conducted and successful separation of the molten iron from the titanium slag is obtained.The obtained vanadium-containing molten iron contains0.681%V and0.267%Ti,and the obtained titanium slag contains52.21%TiO2(mass fraction),in which MgTi2O5is the primary phase.The titanium resource in the final titanium slag production could be used to produce TiO2pigment by acid leaching methods.

Enhanced conversion mechanism of Al-goethite in gibbsitic bauxite under reductive Bayer digestion process

The conversion mechanism of Al-goethite under the action of different additives(lime or reductant for typical or reductive Bayer digestion)was investigated by thermodynamic calculation,XRD,and SEM-EDS.The results show that the formation of Fe-substituted hydrocalumite is crucial to converting Al-goethite to hematite during Bayer digestion by adding lime.However,the conversion proceeds more easily under the action of reductant due to the rapid formation of magnetite.Additionally,Bayer liquor composition significantly affects the product composition and also the conversion rate of Al-goethite.Compared to typical Bayer digestion with Al-goethite containing gibbsitic bauxite as raw material,the red mud yield of reductive Bayer digestion decreases from 39.02%to 31.19%,and the grade of TFe in red mud increases from 41.66%to 53.80%.

Effect of Fe_2O_3/SiO_2 ratio on maghemite-silica particulate nanocomposites

Abstract： Maghemite-silica particulate nanocomposites were prepared by modified 2-step sol-gel process. Superparamagnetic maghemite nanoparticles were successfully produced using Massart＇s procedure. Nanocomposites consisting of synthesized maghemite nanoparticles and silica were produced by dispersing the as-synthesized maghemite nanoparticles into the silica particulate form. The system was then heated at 140 ℃for 3 d. A variety of mass ratios of Fe2O3/SiO2 was investigated. Moreover, no surfactant or other unnecessary precursor was involved. The nanocomposites were characterized using XRD, BET and AGM. The XRD diffraction patterns show the reflection corresponding to maghemite nanoparticles and a visible wide band at 20 from 20° to 35° which are the characteristics of the amorphous phase of the silica gel. The patterns also exhibit the presence of only maghemite and SiO2 amorphous phase, which indicates that there is no chemical reaction between the silica particulate gel and maghemite nanoparticles to form other compounds. The calculated crystallite size for encapsulated maghemite nanoparticles is smaller than the as-synthesized maghemite nanoparticles indicating the dissolution of the nanoparticles. Very high surface area is attained for the produced nanocomposites （360-390 m^2/g）. This enhances the sensitivity and the reactivity of the nanocomposites. The shapes of the magnetization curves for nanocomposites are very similar to the as-synthesized maghemite nanoparticles. Superparamagnetic behaviour is exhibited by all samples, indicating that the size of the maghemite nanoparticles is always within the nanometre range. The increase in iron content gives rise to a small particle growth.

Facile Green Synthesis of Magnetic Fe3C@C Nanocomposite using Natural Magnetite

One simple and environmental friendly synthesis strategy for preparing low-cost magnetic Fe3C@C materials has been facilely developed using a modified sol-gel approach,wherein natural magnetite acted as the iron source.A chelating polycarboxylic acid such as citric acid(CA)was employed as the carbon source,and it dissolved Fe very effectively,Fe3O4 and natural magnetite to composite an iron-citrate complex with the assistance of ammonium hydroxide.The core-shell structure of the as-prepared nanocomposites was formed directly by high-temperature pyrolysis.The Fe3C@C materials exhibited superparamagnetic properties(38.09 emu/mg),suggesting potential applications in biomedicine,environment,absorption,catalysis,etc.

用离子计测量方法研究浮选过程

本文详细分析了于2005年在圣彼得堡纪念普拉克辛院士报告会上有关在实验室中研究浮选过程方法的讨论情况,论述了调浆条件下测试矿浆电化学参数的方法的优缺点。以镍-磁黄铁矿矿石浮选分离过程为例,证明了直接电位检测法的优点。提出了一些关键性的问题,如在调浆过程中药剂的添加顺序、最佳药剂用量以及有关二甲基二硫代氨基甲酸盐和黄原酸盐的新组合形式。

Flotation tree analysis for recovery of sillimanite from red sediments

In this paper an attempt is made to recover sillimanite by flotation tree analysis process and conventional flotation process from non magnetic fraction of red sediments.The experimental results of both the processes are presented.The data reveal that the deslimed sample contains 33.2%(by weight) total heavy minerals and out of which the sillimanite mineral content is 3.6%(by weight).It is observed that flotation tree analysis needs 10 cells to get five output products and where as conventional flotation process needs 15 cells to recover similar grade of five output products.Thus,flotation tree analysis is not only economic process but also efficient process(to say efficient process,the tree analysis product should be higher grade).