Low-grade Iron Ore Research Articles

Recovery of magnetite from low grade banded magnetite quartzite (BMQ) ore

There has been a steady increase of iron ore demand in the last few decades. This growing demand could be countered by use of low grade iron ore after beneficiation. Banded iron formations (BIF) are one of the resources of such low grade iron ores. Banded magnetite quartzite (BMQ) is one such BIF and a source of iron phase mineral in the form of magnetite. In the present study a low grade BMQ ore containing around 25.47% Fe was beneficiated for recovery of magnetite. XRD study shows that quartz, magnetite, hematite, and goethite are the major minerals phases present in the low grade BMQ sample. Unit operations such as crushing, scrubbing, grinding, and magnetic separations were used for recovering magnetite. Based on the large scale beneficiation studies the process flowsheet has been developed for enrichment of magnetite. It was found that with the help of developed process flowsheet it is possible to enrich Fe value up to 65.14% in the concentrate with a yield of 24.59%.

Removal of Silica and Alumina as Impurities from Low-Grade Iron Ore Using Wet High-Intensity Magnetic Separation and Reverse Flotation

This study investigates the removal of silica and alumina as impurities from hematite based low-grade iron ore containing 34.18 mass% iron, 31.10 mass% of silica and 7.65 mass% alumina. Wet high-intensity magnetic separation (WHIMS) and reverse flotation (RF) were investigated. In WHIMS process, 93.08% of iron was recovered with a grade of 53.22 mass% at an optimum magnetic density of 10,000 mT, and pulp density of 2% used the L-4 machine. In RF experiments, optimal results showed 95.95% of iron recovered with 51.64 mass% grade using 1 kg/t of 1% alkaline starch as iron depressant and 1:1 mixture ratio of 0.75 kg/t DAA and NaOL as silica and alumina collectors. The designed multi-stage process involving feeding the concentrate from WHIMS into RF process reduced silica to 2.02 mass%, alumina to 1.04 mass% whilst recovering 81.94% of the iron with 67.27 mass% grade. As a result of this research, a process to produce high quality iron concentrate from hematite based low-grade iron ore with high iron recovery rate was constructed.

Optimization for Production and Processing of Low Grade Iron Ores

The purpose of this paper is to maximize the utilization of low grade iron ores. The production technology of iron ores in Anqian Mining Company was introduced and the ore mass distribution in different production location was analyzed firstly. The processibility indexes for different grade ore, such as grinding time, concentrate grade and the concentrate yield were obtained in the laboratory magnetic tube tests. On the basis of digital ore deposit model which integrates ore natural attributes with processing attributes, the ore blending optimization model containing two stages were established using big M simplex algorithm. The first stage model is to minimize the ore transportation cost under the restriction of output ore grade and pit production conditions. At the second stage, a system optimization model aims at the furthest use of resources. This model meets not only the production constraints of mining and processing field, but also ore beneficiability and the system output requirements of the concentrate ore grade.

Effect of EFB content on reducibility of low grade iron ore composite at 1000°C – 1200°C

This paper focus on reduction of low grade iron at high temperature using palm oil empty fruit bunch as a reductant. The samples were crushed and compacted into composite pellet with EFB before drying at 110°C for 24 hours. The reduction test was then conducted by heating the composite pellet in an electric tube furnace. The parameter used was at temperature range 1000°C to 1200°C and under argon gas atmosphere. The efficiency of the empty fruit bunch in the reduction process was investigated based on the extent of reduction of the iron oxide. The results showed that the extent of reduction obtained was 38.97% at 1200°C. This study demostrates that within the temperature range studied, reducibility of low grade iron ore with an empty fruit bunch tends to increase as the temperature increase.

Integrated Pyrolysis–Tar Decomposition over Low-Grade Iron Ore for Ironmaking Applications: Effects of Coal–Biomass Fuel Blending

One problem associated with ironmaking is the depletion of carbonaceous material (e.g., coal) for iron reduction. A combination of coal and biomass (coal–biomass co-pyrolysis) provides an advantageous synergetic effect to overcome the disadvantage of using renewable raw materials, such as biomass. In this study, we investigated the effect of coal–biomass co-pyrolysis in integrated pyrolysis–tar decomposition over low-grade iron ore. Combined coal–biomass with biomass blending ratios (BBRs) of 0, 25, 50, 75, and 100% were studied by thermogravimetric analysis. A kinetic study on the co-pyrolysis using a double-distributed activation energy model has been conducted. Coal–biomass co-pyrolysis was also performed in integrated pyrolysis–tar decomposition over porous iron ore. The reference line method was used to identify the synergetic effect for each pyrolysis product. A synergetic effect of coal–biomass co-pyrolysis has also been found for decreasing char and heavy tar products as well as for increasing lig...

Studies on selective flocculation of low-grade iron ore using statistical optimization

ABSTRACTIn this study, a two-level and three-variable full-factorial design is used to analyze the behavior of different variables of selective flocculation such as pulp density, pH, and flocculant dosage. The response of low-grade iron ore flocculation was investigated using a two-level and three-variable factorial design. From the studies, the optimal conditions were found to be pH (10), pulp density (6%), and flocculant dosage (0.5 mg/g), and the estimated values of for grade and recovery were 67.52% and 80.17%, respectively. The coefficients of determination (R2) for grade and recovery were found to be 99.80% and 99.97%, respectively.

Biomass briquette as an alternative reductant for low grade iron ore resources

The present study explores the application of biomass briquette, produced from the unutilized vegetative remnants, as an alternative reductant for the reduction roasting-magnetic separation of an iron ore slime sample assaying 56.2% Fe. The X-Ray Diffraction (XRD) studies indicated tridymite and quartz to be the only crystalline mineral phases present in the biomass briquettes while the Fourier Transform Infra Red (FTIR) spectra identified several organic functional groups representing the biomass. Iron ore concentrates with ∼65% Fe and ∼64% weight recovery were obtained with reduction conditions such as temperature: 650–750 °C, reductant to feed ratio: 0.15, reduction time: 30–45 min and reductant size: −3+1 mm. The analysis of the statistically designed experiments suggested that temperature is the most crucial factor followed by time, reductant to feed ratio and reductant size. Magnetite and hematite were found to be the only major phases present in the magnetic fractions produced from roasting at the optimum conditions. Many feebly magnetic phases like wustite, fayalite and clinoferrosilite appeared at higher temperature and reductant to feed ratios, which was confirmed by XRD, reflected light microscopy and quantitative mineralogical analysis.

Reduction Enhancement Mechanisms of a Low-Grade Iron Ore–Coal Composite by NaCl

The reduction behavior of a low iron grade with high SiO2 content ore–coal composite was investigated in the temperature range of 1143 K to 1263 K (870 °C to 990 °C). Sodium chloride was chosen as an additive to promote this reduction process. The effect of the sodium chloride addition and its mechanism was also investigated. Results showed that the added sodium chloride could enhance the reduction of wustite to iron due to the decrease of fayalite, and a higher metallization ratio of reduced sample was obtained. Thermogravimetric–differential scanning calorimeter analysis showed that sodium chloride could greatly facilitate the gasification process of coal and, thus, provide sufficient carbon monoxide to the reduction process of iron oxides. Meanwhile, sodium chloride promoted the reduction process of iron ore pellets directly as the coal gasification effect was excluded. Microstructures of reduced sample revealed that sodium chloride broke the structure of ore and enhanced the growth of newly formed iron particles. As the ore–coal composite with mol (C/Fe = 1.4) and 3 mass pct sodium chloride addition was roasted at 1233 K (960 °C) for 55 minutes, a reduced sample with metallization ration of 74.45 pct could be obtained.

Enhanced recovery of low-grade iron ore by selective flocculation method

ABSTRACTBeneficiation of low-grade iron ore was carried out by selective flocculation process using different flocculants, namely starch amylopectin (AP) and grafted copolymer of amylopectin (GAP). The iron ore used in the investigation contained 56.98% Fe, 5.45% Al2O3, and 4.22% SiO2. Flocculant dosage, number of floc washing, and pH were considered as variable parameters to analyze their effect on the performance of grade and recovery of concentrate. A flocculant dosage of 0.4 mg/g was found to be the optimum condition for the sample and variable parameters under investigation. The investigation indicated that a grade of 64.77% Fe can be obtained with 96% recovery using AP; however, GAP showed the better result for Fe grade (67%) with a recovery of 97%.

Beneficiation of an iron ore fines by magnetization roasting and magnetic separation

The utilization of abundant low-grade iron ores is potentially important to many countries in the word, especially to China. These iron ores contain many detrimental impurities and are difficult to upgrade to make suitable concentrates for the blast furnace. In this paper, the beneficiation of a low-grade hematite ore fines containing carbonates with magnetization roasting and magnetic separation was proposed and studied. The hematite and siderite are almost completely converted into magnetite by 8wt% coal at roasting temperature of 800°C for 8min. Under the optimized conditions, a high grade magnetic concentrate containing 65.4wt% iron with an iron recovery of 92.7% was achieved. Meanwhile, the effects of roasting temperature, reaction time and coal to ore ratio on the magnetic properties of roasted materials were investigated using a vibration sample magnetometer (VSM). The results show that the magnetic susceptibility and magnetism saturation of hematite ore can be highly increased due to the selective conversion of hematite and siderite into magnetite caused by magnetization roasting which facilitates their separation from non-magnetic minerals.

Optimization of Reverse Cationic Flotation of Low-Grade Iron Oxide from Fluorspar Tails Using Taguchi Method

Due to gradual depletion of high-grade iron ores, there is a need to investigate the treatment of low-grade iron ores. Current procedures are time and cost intensive. Batch laboratory scale reverse cationic flotation was employed to concentrate low-grade Fe ore, found in fluorspar tails in the form of hematite. This study used two types of depressants (soluble starch and dextrin) and two types of amines (primary mono-amine and tertiary mono-amine). Optimisation of the process investigated parameters such as pH, collector type and dosage, depressant type and dosage, conditioning time, solids content, agitation speed and air flow rate. Owing to the high number of experiments when all possible combinations are investigated, Taguchi design of experiment method was utilised to streamline the number of experiments and optimize parameters using orthogonal array and signal–noise ratio (SN). The SN was used to determine the optimum conditions and analyse the relative significance of parameters studied. The results showed that both depressants were efficient for hematite depression; however, soluble starch produced better results when compared to Betachem 30D. Both Betacol 373 and Dodecylamine collectors were efficient as quartz collectors; however, Dodecylamine produced better results when compared to Betacol 373. Ranking of parameter using SN ratio showed that pH was the most critical parameter in obtaining higher Fe grade concentrate and the optimum pH is 10. De-slimming leads to low recoveries during reverse flotation of iron ores. The main conclusion is that Taguchi method can be used to optimise a reverse cationic flotation process of a low-grade iron ore.

Removal of Hydrogen Sulfide in Simulated Coke Oven Gas with Low-Grade Iron Ore

The hydrogen sulfide (H2S) removal performance of limonite in the presence of coke oven gas (COG) components (H2, CH4, CO, CO2, and H2O) has been studied in a cylindrical flow-type quartz-made fixed-bed reactor at 300–800 °C under a high space velocity of 51,000 h–1 to develop a novel hot gas cleanup method. The H2S removal behavior by reduced limonite in He does not change at the temperatures examined. On the other hand, the breakthrough curves in 50%H2/He depend on the temperature, and high performance is found at lower temperatures. An investigation of the breakthrough curves of H2S in the presence of COG components at 300–600 °C reveals that the addition of 30%CH4 to 50%H2/He does not influence the performance below 500 °C, whereas the coexistence of 5%CO with 50%H2/30%CH4/He drastically decreases the H2S removal ability of reduced limonite. In addition, the breakthrough curves in 5%CO2 coexisting with 50%H2/30%CH4/5%CO/He are similar to those of 50%H2/30%CH4/5%CO/He. However, the addition of 5%H2O to...

No.45 低品位鉄鉱石と石炭由来炭素質からの高還元性・高ガス化反応性コンポジットの製造(熱分解・コークス(4))

No.45 低品位鉄鉱石と石炭由来炭素質からの高還元性・高ガス化反応性コンポジットの製造(熱分解・コークス(4))

No.15 褐炭・バイオマス由来の低分子量成分と低品位鉄鉱石のコプロセッシング法の検討(重質油・コプロセッシング)

No.15 褐炭・バイオマス由来の低分子量成分と低品位鉄鉱石のコプロセッシング法の検討(重質油・コプロセッシング)

No.13 低品位炭素資源と低品位鉄鉱石のコプロセッシング法の高効率化を目指した炭素/酸化鉄間の接触性向上方法の検討

No.13 低品位炭素資源と低品位鉄鉱石のコプロセッシング法の高効率化を目指した炭素/酸化鉄間の接触性向上方法の検討

1-1-3 低品位鉄鉱石と重質油から調製した鉄鉱石/炭材コンポジットのガス化反応性に及ぼす重質油種の影響

1-1-3 低品位鉄鉱石と重質油から調製した鉄鉱石/炭材コンポジットのガス化反応性に及ぼす重質油種の影響

Novelty on reduction of raw and pre-oxidised titaniferous magnetite ore with boiler grade coal

ABSTRACTPre-oxidation of fines of magnetite containing materials is usually carried out to get better yield of metals. Titaniferous magnetite ore (TMO) is one kind of low-grade iron ore (around 45–50% of total Fe) with a significant amount of TiO2 (23.23%) and V2O5 (0.403%). TMO fines have been pre-oxidised at 973 K (700°C) for 9 h under air atmosphere. The effect of reduction of raw TMO fines as well as the pre-oxidised TMO fines using boiler grade coal in the form of cylindrical briquettes has been studied in the temperature range of 1273 K (1000°C) to 1473 K (1200°C) for periods of 10, 20, 30, 40 and 60 min to estimate the relative yield of iron. The influence of temperature and time on reduction experiments has also been investigated with XRD, FESEM analyses along with chemical analysis of the reduced samples. The most novel result is that the yield of Fe by direct reduction of raw TMO (92.42%) is even marginally better than that of reduction of pre-oxidised TMO (90.89%) at 1473 K (1200°C) for 60 min. Thus the single-step reduction of raw TMO is techno-economically more viable than the pre-oxidation followed by reduction technique.

The effect of particle size on green pellet properties of iron ore fines

Recently, the grade of iron ore deposits has deteriorated and further development of low grade deposits is desired. Presently, the most effective and often followed route taken to utilize such deposits is the provision of beneficiation plants for upgrading iron ore and pelletizing plants for agglomerating. The iron ore fines cannot be directly used in the blast furnace as they severely reduce the permeability of the blast furnace bed and bring down the efficiency of the furnace. To overcome this, agglomeration of high grade iron ore fines is done to serve as blast furnace burden. Both the beneficiation and pelletization techniques are key process in utilization of low grade iron ores. This study deals with the beneficiation and agglomeration of the low grade iron ore; up to the extent such that it becomes an ideal blast furnace feed. Effect of particle size on pellet quality during pellet making has also been aimed and studied along with the development of flowsheet for beneficiation of low grade iron ore.

Integration of mineralogical attributes in evaluating sustainability indicators of a magnetic separator

Early integration of sustainability decisions and mineralogical attributes into the design of minerals processing units offers potential for reducing environmental impacts at mining and processing sites. The objective of this study is to demonstrate how the integration of sustainability indicators and mineralogical attributes could be achieved in developing an integrated modelling framework of a magnetic separator. A magnetic separator unit model based on existing literature was developed to include process stream mineralogical data and to output sustainability indicators. The overall sustainability of processing three ore types (low, medium and high grade iron ore) was evaluated using the developed model. Novel measures for evaluating magnetic separation (Grade Recovery Deviation Index (GRDI)) and energy efficiency (Rotational Energy Transfer Efficiency (RETE)) that incorporate the use of ore characteristics were developed in this study. These measures were used to calculate the separation and energy efficiency sustainability indicator ratings. In total eleven magnetic separator sustainability indicators were identified. Each indicator was assigned a weighting value out of 10 based on its importance. Of the 11 sustainability indicators identified; safety, reliability, Carbon dioxide (CO2) emissions, water use, noise and job creation ratings did not vary with changing mineralogical attributes of the feed ore. GRDI, RETE, electricity cost, particle emissions and waste generation ratings were observed to be dependent on the ore characteristics and therefore their values varied with different feed ore grades. The Analytic Hierarchy Process (AHP) and Weighted Sum Method (WSM) methods were applied to the sustainability indicator ratings and weightings to evaluate an overall sustainability cardinal score of processing a particular ore feed. Results of this study demonstrate the dependence of overall process sustainability indicators on feed ore mineralogical attributes. The results also provide an indication of the effect of ore variability (typical within a single deposit) on sustainability indicators.

Study of particle hydrodynamics and misplacement in liquid–solid fluidized bed separator

Liquid–solid fluidized bed separators are one of the important types of equipment for the beneficiation of low-grade iron ore fines. Particles separate based on the difference in their terminal velocities in these types of separators. Misplacement of particles is a common phenomenon in such type of separators. Qualitative and quantitative studies of the misplacement of particles are essential for the complete understanding of the particle separation. The performance of fluidized bed separators depends on the particle separation. The present study looks into the qualitative and quantitative evaluation of the misplacement of particles inside a fluidized bed separator. The misplacement of particles depends on the particle flow or hydrodynamics. The misplacement of particles, studied using iron ore, quartz and their binary mixtures. The present study uses a new index called “misplacement index” to understand the particle misplacement quantitatively. Effects of different parameters on the misplacement of particles, evaluated experimentally. It is found that mean particle size ratio (MPSR), particle size, static bed height, particle component concentration in the feed, overflow height and superficial velocity have a significant effect on the misplacement of the particles.