Innovative Solutions in Iron Ore Production at Mikhailovsky Mining and Processing Plant

Iron ore and steel production trends and material flows in the world: Is this really sustainable?

Microwave heating is an eco-friendly and novel technique for sintering and heating minerals and materials as it has several advantages in terms of phase transformation, energy efficiency, enhancing speed, process simplicity, improved properties. Such heating provides the composite materials to absorb electromagnetic energy volumetrically and transform into heat and produces larger densities as compared to conventional heating. This study focuses on two main objectives: the recovery of ilmenite through a strategic combination of mineral processing equipment, including a spiral concentrator, followed by magnetic and electrostatic separation, and the enhancement of ilmenite concentrate using microwave heat energy on a cleaner magnetic product, followed by electrostatic separation. Continuous magnetic separation results indicate that among the dry high-intensity belt magnetic separator, box mag wet high-intensity magnetic separator and dry rare earth drum magnetic separators, the rare earth magnetic separator yielded the highest quality product. The application of microwave heat energy before the rare earth drum magnetic separator at 1.4 T, followed by high-tension separation, produced the best grade of ilmenite. The magnetic product obtained after microwave treatment contained 98.6% ilmenite, which was further upgraded to a 99.6% ilmenite concentrate through high-tension separation. Therefore, it is recommended that an effective combination of gravity separation, microwave heat energy, rare earth drum dry magnetic separation and high-tension separation be employed to achieve the highest grade of ilmenite concentrate.

Steelmaking slags are usually processed for iron recovery by dry magnetic separation. The recovered iron-rich products are recycled back into the ironmaking and steelmaking processes to replace high-cost steel scrap and iron ores. However, current slag processing is far away from optimum conditions, especially for slag fines with small particle sizes, resulting in generation of nonrecyclable “metallic” slag fines with insufficient iron content and great iron loss in “nonmetallic” slag fines with excessive iron content. In this research, the authors aimed at enhancing iron recovery from the steelmaking slag fines by process optimization of upgrading the slag fines with dry magnetic separation. The key operating parameters considered in the upgrading process included magnetic drum radius, drum rotation speed, surface magnetic field strength, gradient of the field strength, and splitter position. The first four operating parameters were first combined into a compound variable which represents separation capability (SC) of a magnetic drum separator. Effects of separation capabilities and splitter positions on the separation of steelmaking slag fines were then tested on five different samples of steelmaking slag fines. At last, optimization of the upgrading process on a pilot magnetic drum separator was conducted to maximize recycling ratio of the steelmaking slag fines by adjusting SC and splitter position of the magnetic drum separator.

The National Steel Policy 2005 estimated domestic steel production of 110 MTPA by the year 2019–2020, which was revised by the National Steel Policy 2008, envisaging domestic steel production of the country to be 180 MTPA by 2019–2020. About 2.5 tonnes of ROM iron ore or 1.7–2.0 tonnes of processed iron ore is required for one tonne of steel production. To meet the projected steel production of 180 MTPA by 2019–2020, the iron ore requirement have to be in the order of 500 MTPA which includes long term projected export contracts of around 100 MT. Raw materials are crucial in determining the competitive growth of steel industry as this is an input-intensive extractive industry. Situation calls for proportionate development expansion in adequate raw material supply to meet the demand of Indian steel Industry. India is almost completely self sufficient with regard to iron ore but with future steel production envisaged, an adverse impact on the reserves, position is rather imminent. The existing reserves of hematite (averaging around 63 % Fe) are the only source of iron ore and as such, these reserves may not last beyond 25–30 years at the present rate of consumption. Hence, to meet the future and projected requirement, additional domestic resources have to be created. The ores and minerals are site specific, non-renewable and finite. It is a challenging task for iron ore producers to meet the demand as per the national steel policy. In order to meet the demand, the iron ore producers has to face challenges like increasing the resource base, increasing production and productivity, utilisation of low grade iron ores, beneficiation of low grade fines and slimes, overcoming the infrastructure bottlenecks like roads, railways, ports, power, capital and water, human resource, handling, storage and utilisation of slimes/tails, encouragement for R&D activities, adopting environmental friendly measures and land acquisition for setting up new plants. In this paper all the above aspects are discussed thoroughly.

Recovery and grade are the two crucial performance parameters commonly used in mineral processing plant operations. These two parameters are interdependent. An increase in recovery would result in a decreased product grade and vice versa. The present study enumerates concentration efficiency (CE),which can be adopted exclusively for processing low-grade hematite ore by WHIMS—the reverse flotation route to produce a pellet grade concentrate. In this study, the ore’s amenability by wet high-intensity magnetic separation followed by the reverse flotation of a magnetic concentrate route is investigated on BHQ samples of the Sandur schist belt (Kumaraswamy hills), India, after its characterization by microscopic and XRD studies. Dodecyl amine acetate was used as a collector to float siliceous gangue while depressing hematite using the freshly synthesized caustic starch as a depressant. The separation efficiency of the flotation was evaluated by estimating the grade, recovery, and concentration efficiency. The WHIMS conducted using the feed with the particle size minus 106 µm (d80 = 82 µm) followed by reverse flotation produced a pellet grade concentrate assaying 64.60% Fe, a 0.32 alumina-to-silica ratio with 60.4% Fe recovery, and a yield of 37.4% with 79.0% concentration separation efficiency.

Background/Objectives: Due to soaring demand and rapid depletion of high-grade iron ores, lean grade iron ores of India like BHJ and BHQ needs to be utilized through suitable beneficiation techniques. Methods: Banded Hematite Jasper (BHJ) sample of Bonai-Keonjhar belt (BK belt), Odisha, India assayed 35.3 % Fe, 47.1% SiO2 and 0.96% Al2O3 was investigated in respect of mineralogy, liberation characteristics and chemistry to finding out its optimum beneficiation potential. In the present investigation, efforts have been made to characterize the BHJ sample with reference to its beneficiation response. The sample was subjected to various beneficiation operations like Jigging followed by hydrocyclone, two-stage tabling and magnetic Separation. Findings: Mineralogical studies indicate that quartz and hematite are the major mineral phases, whereas goethite, martitized magnetite and clay (kaolinite) are present in very minor amounts. The liberation characteristic indicates that the average band thickness of Iron bearing mineral is of 1680 microns and 80% of the iron bearing minerals are liberated at -105 microns size. The two stage tabling of jig concentrate with desliming gives better outcome as compared with direct tabling of jig concentrate. An iron ore concentrate assayed 64.5% Fe, 5.6% SiO2 and 0.80% Al2O3 with wt% recovery of 23.2% can be obtained from two stage tabling. Another concentrate from magnetic separation of table middling and hydrocyclone assayed 63.2% Fe, 7.2% SiO2 and 0.7% Al2O3 with wt% recovery of 12.4% can be obtained. Novelty/ Application: Here a conventional beneficiation flow sheet is developed with a finding that, in order to beneficiate ore like banded hematite jasper (BHJ), an integral characterization approach is very much essential. Both of the concentrates obtained through the flow sheet assayed 64% Fe, 6.2% SiO2 and 0.7% Al2O3 with a wt% recovery of 35.6% can be utilized as a feed stock for pellet making in iron ore industries. Keywords: Banded Hematite Jasper (BHJ); mineral beneficiation; wet high intensity magnetic separator (WHIMS); jigging; Bonai-Keonjhar belt

In order to improve the grade of iron, upgrading of laterite ore was conducted using wet low intensity magnetic separator. The ore was treated through selective reduction followed by sulphuric acid leaching to recover nickel while iron remained in residual solid. The Vibrating Sample Magnetometer measured the magnetic properties of the ore, as a fundamental of magnetic separation. Magnetic separation was carried out using a Davis Tube Tester. The effect of pretreatments on the magnetization and magnetic separation were investigated.The results showed that the ore has similar magnetic property with goethite. The heating of the ore at 673 K did not improve significantly on its properties whether goethite changes to magnetite. However, the reduction treatment increased the magnetic properties of the ore due to the formation of magnetite. The magnetic susceptibilities of the original, heated and reduction treated laterite ores were 2.36×10−5, 2.18×10−5 and 2 357×10−5 emu/g, respectively. The correlation between magnetite content and magnetization of the magnetic concentrate was showed in a linier equation, which could be used for the prediction of magnetite content in the sample based on its magnetization. Magnetic separation was applied only to recover iron from the laterite ore after being treated by the selective reduction in which magnetite was produced. About 93.9% of magnetite was upgraded from the laterite ore with 90% of recovery was obtained. The relatively high iron content in the magnetic concentrate indicated a potential use as raw material for iron making.

The paper analyzes the tasks of producing high-quality iron ore concentrates suitable for nonblast-furnace metallurgy and the challenges of processing magnetite ores with the current technological level of dressing equipment and technologies. One of the best methods to improve the quality and the grade of iron ore raw materials is the use of magnetic gravity separation in the technological process, which allows selective separation of the liberated magnetite particles from their aggregates in processing of undersize products of fine vibrating screening. This trend is implemented in the innovative magnetite ore processing technology that uses the principle of the staged output of finished concentrate. The technology makes it possible to produce a high-quality concentrate after the first grinding stage. The magnetic gravity separation has undergone industrial validation, has proven its efficiency in practice, and has become widespread at mining and processing plants not only in Russia, but also in the CIS countries. Over 180 MGS-2.0 magnetic gravity separators produced by Russian manufacturers have already been or are being implemented at various Russian and CIS companies. Industrial separators are equipped with modern automation systems providing high technological separation performance, have no rotating parts and are simple in design. The authors continue R&D works on creation of automated control systems for the magnetic gravity separation process based on designing digital models adapted for introduction into the plant’s automated process control systems.

Mineral dry density separation behavior (mineral beneficiation) involves segregation of high density particles and low density particles in the feed, i.e., in nutshell, mineral dry density beneficiation is density segregation in physics terms. In dry beneficiation, this density segregation is achieved using air as fluidized medium. Density segregation on dry separators can be achieved in two ways: (1) using minimum fluidization velocity differences and (2) using terminal velocity difference between different density particles. Dry separators based on minimum fluidization velocities follow two steps for dry beneficiation: (1) vertical density stratification and (2) horizontal segregation. Particles due to buoyancy, drag and gravitational forces get vertically density stratified and later frictional, gravity and external (vibrational, etc.) forces horizontally segregate different density particles. Dry separators based on terminal velocities follow single step for dry beneficiation of mineral, and air velocity in this type of dry density separators is maintained between terminal velocity of high density and low density particles. Velocity of air is higher for low density particles, which leads to higher drag and buoyancy forces to get pushed out of system with air and get collected at further distance than high density particles leading to density segregation. Mathematical models have been developed using force balance on particles and simulated in MATLAB for both type of separators to explain the physics of separation. Solutions to the simulated mathematical model equations are the particle trajectories of different density particles in the two dry separators. Iron ore is used as feed for studying separation futures in mathematical modeling on dry separators.

An analysis of the performance indicators of the main high-performance excavators used at leading coal mines and iron ore mining and processing plants in Russia showed that the actual average monthly productivity of excavators achieved at mining enterprises is lower than the calculated technical one by 30% or more. To increase it, it is necessary to minimize negatively influencing factors and optimize the operation of the excavator-automobile complexes. The possibility of this is confirmed by the information available in the scientific and technical literature on record productivity indicators established at mining and processing plants and open-pit mines during full-scale experiments. The choice of excavator-automobile complexes is a relevant and important task at the design stage of new enterprises, or justification of the optimal parameters of the loading and hauling equipment in conditions when the existing quarries are going deeper or expanding and the productivity of mining and processing plants is increasing, as well as for comparing various technological options for the development of deposits. One way to solve this issue may be computer simulation of the functioning of both the individual elements (excavators, dump trucks, excavatorautomobile complexes, etc.) and the quarry transport system as a whole. The Institute of Mining of the Ural Branch of the Russian Academy of Sciences has developed the In-Pit Transport System software suite, aimed, among other things, at solving these problems.

The Geochemical atlas of Alaska

Red mud as the main byproduct generated during alumina extraction from bauxite. Owing to the high iron content in the red mud and the high correlation between iron and scandium during the leaching process, it is necessary to extract the iron from the red mud and to further enrich the scandium in advance for the acid leaching extraction of scandium. In this research, the theory of red mud segregation roasting ore phase reconstruction is proposed, so that the iron and scandium in the red mud undergo a corresponding transformation, thereby achieving iron recovery in magnetic separation concentrate by magnetic separation, and enrichment of scandium in magnetic separation tailings. On this basis, the effects of temperature, leaching time, solid to liquid ratio and hydrochloric acid concentration on the leaching of scandium in magnetic separation tailings were studied optimal leaching process conditions and determine the leaching kinetics. A maximum Sc leaching efficiency of 83.94% was obtained at optimum leaching conditions of 200 rpm agitation speed, hydrochloric acid solution 20%, 80°C for 3 h, and solid/liquid ratios 1:10 (g/mL), −74 µm sample particle size. The process of leaching scandium with magnetic separation tailings conforms to the kinetic characteristics of multiphase liquid-solid region reaction, the apparent activation energy of scandium is 26.77 kJ/mol, and the leaching efficiency of scandium is controlled by the chemical reaction step.

Assessing the performance of a novel pneumatic magnetic separator for the beneficiation of magnetite ore

The paper presents the results of the research aimed at recovery of hematite from current and stockpiled tailings produced at the mineral processing plant of Olkon JSC. The authors investigated material composition of tailing samples. Using methods of computational fluid dynamics and the ANSYS software, the models of spiral separation of the tailings have been developed. The use of computer modelling has shown that spiral separators can be recommended for tailings processing. The modelling results were confirmed with industrial spiral separation tests conducted at the processing plant. The authors developed a gravity separation technology for processing the magnetic separation tailings and stockpiled tailings. The proposed technology allows recovering hematite concentrate with a hematite iron content of 54.5% and recovery of 75.4% from current tailings containing 5.2% of hematite iron. It was also shown that hematite concentrate can be recovered from stockpiled tailings using the separation technology based on the use of spiral separation. The gravity separation technology provides for resources economy at the mineral processing plant. The use of stockpiled tailing as a raw material source can reduce negative environmental impact.

Owing to its unique properties, pyrophyllite is an economical alternative to many minerals in different applications. The presence of iron-bearing minerals in Saudi pyrophyllite hampers its industrial uses. The aim of this study was to examine the removal of iron from Saudi low-grade pyrophyllite ore using two approaches. The first approach involves dry high-intensity magnetic separation, whereas the second approach involves microwave pretreatment of the ore before dry magnetic separation. For the first approach, the studied operating parameters were roll speed; feed rate, field intensity, and feed particle size. For the alternative approach, microwave treatment followed by dry magnetic separation, the microwave irradiation time and the magnetic field intensity were studied. The results show that the combined microwave treatment and dry separation method could provide high-purity pyrophyllite for filler industries. Microwave irradiation for 30 min was optimal to change impurity phases (i.e., pyrite, hematite) into ferromagnetic phases in microwave-treated pyrophyllite samples. At a magnetic field intensity of 2000 Gauss, the 30 min microwave-irradiated pyrophyllite sample achieved an iron recovery of 11.2% in non-magnetic fractions, with a removal efficiency of 89% with an alumina recovery of 91.31%.