Recovery of Ultra-Fine Iron Ore from Iron Ore Tailings

Many attempts has been taken for further utilisation of the tailings and slimes through different routes i.e. beneficiation, agglomeration etc. Though the slimes and tailings contain huge ultra fines, conventional beneficiation methods many not be much effective for handling because of particle size limitations. Physicochemical method i.e. selective flocculation is a process for handling the ultrafine particles present in the tailings. Review shows that selective flocculation technique have very limited commercial application. Here the study focuses on the application of selective flocculation process for beneficiation of synthetic mixtures of iron ore and kaolinite as well as iron ore tailings. Results show that it is possible to achieve 65.78(%) of Fe, with 2.65% Al₂O₃, 3.66 SiO₂ (%) in the concentrate using synthetic mixture feed and more than 60% of Fe is obtained from natural iron ore tailings.     

Study of the phase composition of metallurgical slimes by Mössbauer spectroscopy

The phase composition of blast-furnace and electric-furnace slimes is studied by Mössbauer spectroscopy and X-ray diffraction. The iron distribution over iron-containing phases in the slimes is studied. As a result of analyzing the Mössbauer and X-ray diffraction spectra of the slimes, it is found that a number of elements present in the slimes form solid solutions with iron oxide phases. A combination of Mössbauer spectroscopy and X-ray diffraction is shown to give the most full and precise data on the character of the iron-containing phases existing in metallurgical slimes.     

Preparation of Iron Ore Micro-pellets and Their Effect on Sinter Bed Permeability

At present around 6–7% of iron ore slimes, out of total production, are being generated and accumulated at iron ore mine sites of National Mineral Development Corporation Limited, India. The accumulated slimes of finer size and relatively inferior grade should be utilized in an economical way for sustainable mining. These slimes can be agglomerated into micro-pellets for subsequent use in sinter making through hybrid pellet sintering method. However, the micro-pellets of sufficient size and strength are required for hybrid sinter making. The green properties of the micro-pellets depend upon various parameters such as surface area, moisture, binder, etc. In this study, iron ore slimes were beneficiated through gravity, and magnetic separation and concentrate of grade 65% Fe (Total) was obtained. Since the concentrate obtained had low surface area (700–900 cm²/grams) rendering it unsuitable for micro-pellet making, it was further subjected to grinding in a ball mill. The requirement of surface area for producing an optimum quality of green micro-pellets was established. The resultant micro-pellets were further used in studying sinter bed properties. The effect of moisture and size of micro-pellets on permeability of sinter bed were examined. The results confirmed that the addition of micro-pellets to the sinter mix improved the permeability of the sinter bed. The sinter bed with highest permeability of JPU 25.25 and void fraction of 36.27% was achieved with micro-pellets of size 3–6 mm at 7% moisture level. Mean granule size of sinter mix was also studied with respect to moisture content and size of the micro-pellets.     

重铬酸钾法快速测定钛铁矿中钛铁含量

利用磷酸脱水后的缩合物具有较强的酸性和配位性,试样经磷酸在高温下加热5 min溶解后,在酸性条件下,被铝片,氯化亚锡还原,然后以中性红和二苯胺磺酸钠作指示剂,采用重铬酸钾滴定法分别测定了钛铁矿中钛、铁含量。研究了溶样条件、样品细度、溶解时间和还原酸度对测定的影响,确定了最佳实验条件。采用本方法对实际样品中钛、铁进行测定,测定值与经典的硫酸高铁铵 汞盐法测得结果一致,相对标准偏差(n=5)均小于02%和05%。采用本方法对钛铁矿标准样品（YSBC19704 76）中钛、铁进行5次测定,测定结果与认定值相符,相对标准偏差分别为012%和062%,。     

富氧顶吹熔融还原冶炼高磷铁矿与钛铁矿配矿的试验研究

采用模拟HIsmelt的富氧顶吹熔融还原技术冶炼惠民高磷铁矿与勐桥钛铁矿配矿,在温度为1 500K,碱度为1.3,配碳比为1.0的条件下,恒温时间20min(在升温过程中,没有通入惰性气体),恒温过程中通入O2(流量250L/h、纯度为99%)10min。恒温时间结束后,调整氧气流量为5L/h,保持其氧化性气氛至冷却。研究了不同配矿比例对铁回收率、生铁中磷、硫含量以及磷、硫分配比的影响。研究结果表明,在惠民铁矿和勐桥精矿的比例为1∶1时,其冶炼结果比较理想:铁的回收率为95.1%,生铁中磷的质量分数约为0.32%,硫的质量分数为0.054%,钛的质量分数为0.031%。     

Obtaining and investigating wear resistance of a composite material based on titanium carbosilicide

A composite material (CM) based on titanium carbosilicide with a titanium carbide content of 50% possessing a microcrystalline structure is obtained by mechanosynthesis in a planetary mill with subsequent hot pressing. The highly nonequilibrium structure of the powder material, which forms due to the high-energy treatment, makes it possible to obtain material with a relative density of 96% at a hot-pressing temperature of 1400°C and a pressure of 20 MPa. Comparative tests of the CM and silicon carbide for wear resistance under different conditions are carried out. The CM based on titanium carbosilicide showed less wear of the counterbody and a lower friction coefficient in all cases. However, in tests using an abrasive medium, wear of the composite material itself is observed.     

Joint aqueous leaching of read slime and greasy scale

A new approach to the development of utilizing two types of anthropogenic waste, namely, red slimes from processing bauxites (including Ural plants) and grease scale of the rolling production, which involves their joint processing with the acquisition of a product suitable for the recovery of the main components using blast furnace smelting for cast iron and alumina slag, is developed. To complete the investigations, a technological simulation of the processes of leaching, filtration, and drying is used. Optimal leaching parameters that provide a high filtration rate of the pulp suitable for the purification of industrial and sanitary waters and the acquisition of 52?C56% iron in the cinder are established.     

Processing of Alumina-Rich Iron Ore Slimes: Is the Selective Dispersion–Flocculation–Flotation the Solution We Are Looking for the Challenging Problem Facing the Indian Iron and Steel Industry?

Beneficiation of alumina rich iron ore slimes is a major challenge for the Indian iron ore industry. Considering the limits of gravity and magnetic separation processes in the relatively finer size range in terms of achieving adequate separation efficiency, selective flotation (with and without selective flocculation) of iron ore slimes, which is being used commercially in several countries for the beneficiation of iron ores, is worth exploring for the beneficiation of Indian iron ores. Based on the extensive work carried out in our laboratories, we have concluded that the design and development of highly selective reagents to achieve satisfactory separation of hematite and goethite from alumina containing minerals (gibbsite or kaolinite) in the ore and ore slimes, is the key to solving the challenging problem of processing alumina rich iron ores. Accordingly our research work has been focused on finding/designing selective reagents for iron oxide–gibbsite–kaolinite separation based on a molecular modeling computational approach developed by us for the design of mineral processing reagents. We present in this paper the results of our density functional theory computations to evaluate the interaction energies of a wide variety of different reagent functional groups such as carboxylic acid, hydroxamic acid, phosphonic acid, iminobismethyl phosphoric acid, xanthate and starch with hematite, gibbsite and kaolinite surfaces. Among all the reagents investigated so far, starch exhibits the highest selectivity towards the hematite surface with a difference in interaction energy of ~63 kcal/mol between hematite and gibbsite surfaces. Based on our earlier work which indicated polyvinyl pyrrolidone (PVP) to be more selective dispersant for kaolinite compared to conventional sodium silicate and sodium hexametaphosphate, we have investigated selective flocculation–dispersion of natural iron ore slimes (three different samples obtained from three different mines in India) with PVP and starch reagent combination. The results are promising. While the work is still in progress, the implications of our recent results are discussed in the context of the challenging problem of processing of alumina rich iron ore slimes in India.     

Thermodynamics of titanium-based melts: I. Thermodynamics of the dissolution of elements in liquid titanium

A method is described that involves the molar interaction parameters in liquid iron at a temperature of 1873 K, provides calculation of these parameters in liquid titanium at any temperature, and makes it possible to calculate the heats of dissolution of elements in liquid titanium and the activity coefficients of these elements. The changes in the Gibbs energy caused by the dissolution of some alloying and impurity elements in liquid titanium are calculated, and the activity coefficients of these elements are presented.     

提高钒钛球团矿碱度试验

介绍了配加0、2％、3％、4％石灰石粉提高钒钛球团矿碱度实验室试验的情况,得出了提高钒钛球团矿碱度,有利于改善球团矿的部份热态性能,提出了竖炉生产一定碱度钒钛球团矿适宜的工艺技术参数。     

Recovery of Iron From High-Iron Red Mud by Reduction Roasting With Adding Sodium Salt

 Red mud is the waste generated during aluminum production from bauxite, containing lots of iron and other valuable metals. In order to recover iron from red mud, the technology of adding sodium carbonate—reduction roasting—magnetic separation to treat high-iron red mud was developed. The effects of sodium carbonate dosage, reduction temperature and reduction time on the qualities of final product and the phase transformations in reduction process were discussed in detail. The results showed that the final product (mass percent), assaying Fe of 90.87% and Al2O3 of 0.95% and metallization degree of 94.28% was obtained at an overall iron recovery of 95.76% under the following conditions of adding 8% sodium carbonate, reduction roasting at 1050 ℃ for 80 min and finally magnetic separation of the reduced pellets by grinding up to 90% passing 0.074 mm at magnetic field intensity of 0.08 T. The XRD (X-ray diffraction) results indicated that the iron oxides were transformed into metallic iron. Most of aluminum mineral and silica mineral reacted with sodium carbonate during the reduction roasting and formed nonmagnetic materials.     

Investigation into the compaction of nanopowders and micropowders of silicon carbide in high-pressure apparatus

The results of the investigation into the compaction (sintering) of silicon carbide nanopowders and micropowders in a DO-138 high-pressure apparatus are presented. Compaction modes for both types of materials are identical (a pressure of 3.5–4.0 GPa, a temperature of 1600—1700°C, and a holding time of 10 s). The influence of cladding of SiC nanopowders and micropowders with titanium and titanium nitride on the properties of compacts (cakes) formed under the same sintering modes is investigated. It is established that, when compacting the silicon carbide nanopowder, cakes differ in regards to higher density, hardness, and lower porosity compared with the samples made of finely dispersed technical silicon carbide. A higher activity of titanium relative to SiC makes it possible to chemically associate the grains of the latter due to the formation of intermediate layers of titanium carbide between them. The resulting ceramics possesses a higher density, hardness, and wear resistance. The wear resistance of synthesized composites based on nano-SiC is higher than for a polycrystalline material based on silicon carbide micropowder by a factor of 4.5.     

Alumina extraction from northeastern red soils of Argentina

A laboratory-scale acid process to produce alumina with a purity higher than 98.4% from the northeastern red soils of Argentina is proposed. Leaching was carried out with 6 M hydrochloric acid at several molar ratios both with and without previous thermal treatment of the mineral. The relationship between the extent of dissolution of iron (II), iron (III), aluminium (III) and titanium (IV) and the structure of the principal minerals of the soils were analyzed. The solutions obtained after leaching, containing about 30 g/l of aluminium and iron oxides and 1 g/l of titanium oxide, were purified by solvent extraction and hydrolytic precipitation. The related behavior of the system aluminium (III) - iron (III) in hydrochloric acid with the organic solvent tributyl phosphate and the conditions suitable for titanium hydrolysis were studied. Then, hydrated aluminium chloride was obtained by crystallization and thermal decomposition of the salt was carried out to produce alumina.     

The self-propagating high-temperature synthesis of a nanostructured titanium nitride powder with the use of sodium azide and haloid titanium-containing salt

The use of the “ammonium hexafluorotitanate (NH₄)₂TiF₆-sodium azide NaN₃” system during self-propagating high-temperature synthesis (SHS) allows researchers to obtain nanostructured titanium nitride powder. Nanopowders of silicon, boron, and aluminum nitrides are formed from similar “halogenide of nitrided element-sodium azide” systems by SHS. It is confirmed that the use of compounds rather than pure elements in the starting powder mixtures for SHS makes it possible to substantially decrease the dimensionality of the combustion products and obtain them in the form of nanostructured particles, nanofibers, and nanopowders.     

A Mineralogical overview of the behavior of nickel during copper electrorefining

Nickel-bearing copper anodes and anode slimes were studied using a variety of mineralogical and chemical techniques. In anodes containing <;0.3 pct Ni, the nickel occurs only in solid solution in the copper matrix. This nickel dissolves simultaneously with the copper during electrorefining, but a small amount reprecipitates as copper-nickel sulfate or a complex Ni-bearing Cu-Ag-As-Se-S oxidate phase in the anode slimes. In anodes containing >0.3 pct Ni, NiO crystals also form. The presence of the Cu-Ni-Sb oxide, kupferglimmer, in the anode depends on its antimony content. Kupferglimmer is prevalent in nickel-rich anodes with high Sb contents (>200 ppm) but is not found in similar anodes with Sb contents <200 ppm. Various Cu-Ni and Ca-Cu-Ni silicate inclusions are present. Depending on the iron content of the anode, Fe-bearing NiO, NiFe₂O₄, and other Ni-bearing iron oxide phases also may be present. All of the oxidate nickel phases remain largely undissolved during electrorefining and concentrate in the anode slimes.     

Rational Processing of Refractory Copper-Bearing Ores

The results of material composition studies of four samples of refractory copper-bearing ores of the Uzelga deposit are presented along with the results of studies of technological solutions to increase their processing parameters. The refractoriness of ores is associated with a thin dissemination up to micron size and close interbreedings of ore and rock minerals. Iron sulfides are presented by a wide range of minerals: pyrite and marcasite, melnikovite, arsenic pyrite, and arsenopyrite; sooty melnikovite has an increased flotation activity. The grinding of iron sulfides from 89 to 29% is followed by a proportional increase in easily floatable rock minerals to 45% and clay to 9%. These properties make these sulfides difficult to process and retain ore refractoriness to the flotation concentration. The content of copper sulfides in ore samples varies from 3.32 to 7.29%; the relative portion of copper sulfide in a form of tennantite in different samples of deposit varies from 29 to 93%. Copper is also present in a form of chalcopyrite and bornite. The best flotation activity of tennantite can be seen in a neutral and slightly acidic medium, in contrast with the standard flotation regime for chalcopyrite and bornite with butyl xanthate in a high-alkaline calcareous medium. Free grains of copper minerals can be selectively extracted into intercycled concentrates during grinding of no more than 60% of the class–71 μm. The technology of flotation in a low-alkaline medium with M-TF selective sulfhydril collector in the intercycle copper flotation and refinement cycle of the copper concentrate is developed for refractory copper-bearing ores with a variable tennantite content. Aeration is applied to suppress the flotation activity of melnikovite, which makes it possible to attain 80% copper recovery into a conditional copper concentrate. The fine inclusions of bornite, tennantite, chalcopyrite, and sphalerite into pyrite makes it rational to obtain copper–pyrite and copper–zinc–pyrite products with a yield up to 12% for pyro- and hydrometallurgical processing, along with the isolation of enriched copper concentrates.     

Titanium Carbonitride Composite with Iron ― Chromium Binder

Wetting of titanium carbonitride with iron ― chromium alloys has been studied in the concentration range 2-30 mass% Cr. Chromium is shown to be a surface-active additive that decreases wetting angles in the TiCN ― (Fe ― Cr) system. The results of the investigations made it possible to choose the optimum composition of titanium-carbonitride material. A technology has been developed for the fabrication of new composite and some properties of this composite have been determined.

     

甘肃某含钛磁铁矿选矿试验研究

甘肃某含钛磁铁矿含钛6.58%,含铁21.46%,具有较大的回收价值.在工艺条件试验研究的基础上,采用"弱磁选铁-强磁预富集-钛浮选"的工艺流程回收有价金属,最终,实验室小型闭路试验可获得含铁61.75%,全铁回收率43.45%（磁性铁回收率达86.47%）的铁精矿和含钛50.10%,钛回收率60.23%的钛精矿,浮选作业回收率为85.94%,选别指标较好.      

提高攀枝花红格矿区钒钛磁铁矿回收率的工艺研究

攀枝花红格钒钛磁铁矿储量丰富,且伴生的铬、钴等稀有元素的含量均比较高,极具开发价值.由于该矿铁矿品位低,脉石矿物很难被剔除,有用矿物嵌布粒度细微的特点,至今该矿利用水平还较低,钛的综合回收率仅30%左右.本文通过粗粒抛尾——阶段细筛闭路磨矿——阶段选别的选铁工艺,及高梯度强磁—离心重选抛尾—浮选脱硫—浮钛,最终获得TW...     

Separation and recovery of iron and scandium from acid leaching solution of red mud using D201 resin

Red mud is a byproduct of alumina refining of bauxite ores, and is a significant source for extracting scandium. However, a large amount of iron in red mud makes it difficult to recover scandium because Fe(III) and Sc(III) have similar physicochemical properties. In this study, a new method was developed for selective separation of iron and scandium in acid leachate of red mud using D201 resin. Theoretical calculations indicate that the ferric species mainly exists as FeCl₃ or FeCl₄⁻ at chloride concentration above 6.65 mol/L, while scandium still exists as ScCl₂⁺, making it possible to selectively separate iron from scandium through anion resin adsorption. The factors affecting the adsorption of iron and scandium such as chloride concentration, resin dosage, adsorption time, and temperature were evaluated in batch experiments. The Langmuir model was successfully applied to both iron and scandium adsorption, and the maximum adsorption capacities of iron and scandium are 147.06 and 0.95 mg/g, respectively, indicating a significant difference between iron and scandium. Raman analysis further demonstrates that the iron is adsorbed onto D201 resin as FeCl₄⁻ anion.