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The average grade of iron ore is low in China, and it is significant for the effective utilization of iron ore to obtain grades. In the paper, the high-precision model was constructed based on the spectrum of hematite and the multiple hidden layers extreme learning machine with random values and dense connection, which took the output of all previous layers as the input of each hidden layer. It has achieved high precision during the detection of the total iron content for hematite, which meets the requirements for the construction and development of new green and intelligent mines. [ABSTRACT FROM AUTHOR]

In this study, the desulphurization of iron ore concentrate using reverse flotation was investigated. In this paper first, behavior of the flotation of both pure – pyrite and iron oxides-pyrite with xanthate has been examined based on micro-flotation results and zeta-potential measurements. Then, an effort has been made to investigate the effect of pH, chemical reagent dosages, impeller speed, pulp density, flotation time and conditioning time parameters on desulphurization of actual iron ore concentrate using lab-scale mechanical flotation cell. Results of zeta-potential measurements displayed that iso-electric points (IEP) for pure and iron oxides-pyrite were around pH 7 and 8, respectively. Based on the micro-flotation results, the recoveries were highly dependent on pH. Both pyrite types showed high recoveries at pH 4.75 to 8, but in the flotation of iron oxides-pyrite, partial depression was found in the pH range of 6–7. The presence of iron ions in solution considerably depressed iron oxide-pyrite flotation in the pH range of 2.5–3. Recovery of both pyrites decreased dramatically when going from pH 10, due to the formation of iron hydroxides and the instability of dixanthogen. According to the data obtained from batch flotation tests, the maximum recovery of total sulfur was achieved when the operational parameters were set to the PAX dosage 200 gr/t, MIBC dosage 150 gr/t, CuSo4 75 gr/t, impeller speed 1500 rpm, pH 7.5, flotation time 7 min and pulp density 30%. With these optimum parameters, final concentrate with the grade of 69.48% Fe and 0.1% S was obtained. [ABSTRACT FROM AUTHOR]

Currently exploited iron ores have high-manganese content. Conventional leaching of manganese takes about 2 h at 80 ̊C followed by precipitation. Thus, it consumes high energy and a relatively long-time. In this paper, the mechanochemical method was investigated for reducing manganese in iron ore at a shorter time and at room temperature. The number and size of balls were studied during the milling process in the presence of sulfuric and/or oxalic acid either as a single acid or as a mixture. The higher the ball's number and size the higher the iron and manganese dissolution. The sulfuric-oxalic acid mixture is better than the usage of single acid for reducing the manganese at about 10 min. The iron concentrate, containing 54% Fe and 2.9% Mn from a feed containing 57% Fe and 7.5% Mn, is obtained using 15 balls of size 3.3 cm and 2%:4% sulfuric to oxalic ratio and dosage. Moreover, the mechanochemical is advantageous over conventional leaching as it continuously cleans the surface, creates new surfaces, controls iron dissolution, is conducted at room temperature and shorter time (about 10% of the time needed for the leaching process), and direct production of iron concentrate without subsequent processes like precipitation. [ABSTRACT FROM AUTHOR]

This paper proposes a method to probabilistically quantify the moments (mean and variance) of excavated material during excavation by aggregating the prior moments of the grade blocks around the given bucket dig location. By modelling the moments as random probability density functions (pdf) at sampled locations, a formulation of the sums of Gaussian-based uncertainty estimation is presented that jointly estimates the location pdfs, as well as the prior values for uncertainty coming from ore body knowledge (obk) sub-block models. The method was tested in a region situated in the Brockman Iron Formation of the Hamersley Province, Western Australia. [ABSTRACT FROM AUTHOR]

Archaeological research at Hoeke, a Late Medieval outer harbour of Bruges (Belgium), has revealed large quantities of iron slags, fuel and other remains of iron working. Archaeometrical study has provided an enhanced insight into the historic iron working process, a craft activity which had up till now remained completely unknown in one of the largest economic hubs of medieval Europe. Several petrological, mineralogical and geochemical analytical methods have been applied for this purpose. The metallographic analysis was performed using reflected light optical microscopy, while the mineralogical composition of the slags was characterized X-ray Diffraction (XRD) Spectrometry. Macroscopic identification of plano-convex bottom slag and hammerscales, combined with the geochemical data pointed out that the examined slag is indicating smithing activity, while no traces for iron ore melting were discovered. [ABSTRACT FROM AUTHOR]

The Guandi and Banshigou iron deposits of southern Jilin Province, China, are Algoma-type banded iron formations (BIFs) located in the Eastern Block of the North China Craton (NCC). LA–ICP–MS U–Pb dating shows the magmatic zircons in plagioclase amphibolite from the Guandi BIF (PA–GD) and plagioclase hornblende gneiss from the Banshigou BIF (PHG–BSG) were crystallised at 2556 ± 17 Ma and 2545 ± 27 Ma, respectively, representing the formation age of the BIFs. Metamorphic overgrowth zircons from both samples gave two U–Pb ages of 2452 ± 23 Ma and 2446 ± 70 Ma, indicating the age of metamorphism. The zircon εHf(t) values of PA–GD (–1.3 to +2.8) and PHG–BSG (–1.5 to +2.7) indicate that the magma source was derived from depleted mantle with contamination of crustal material. According to our study, the PA–GD and PHG–BSG were formed in an island arc setting and support previously proposed subduction zone tectonic models for the northeastern NCC during the Neoarchean. The magmatic zircons from the PA–GD and PHG–BSG were crystallised at 2556 ± 17 Ma and 2545 ± 27 Ma, which represents the formation age of the BIFs. The metamorphic overgrowth zircons from the PA–GD and PHG–BSG gave two ages of 2452 ± 23 Ma and 2446 ± 70 Ma, which represent the age of metamorphism. Major-element and REE data indicate that BIFs precipitated in a mixture of seawater and hydrothermal fluids in an anoxic environment. Geochemical and Hf isotope characteristics of BIFs' wall rock indicate that the source magma was derived from a depleted mantle wedge metasomatised by subduction-slab melts and contaminated by ancient crust, formed in an island arc setting. [ABSTRACT FROM AUTHOR]

Goa, a biodiversity hotspot, is also a major iron ore producing state in India. This study investigated total heavy metal (HM) contamination in 65 georeferenced soil samples through inductively coupled plasma atomic emission spectrophotometer (ICP-AES) for assessing risk of mining activity on agricultural soils. The mean concentrations of copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), chromium (Cr), cadmium (Cd), manganese (Mn), iron (Fe) and cobalt (Co) were 125.60, 75.60, 96.40, 51.20, 69.30, 25.77, 2091, 162638 and 21.20 mg kg−1, respectively. Lower pH, higher organic carbon (OC) and fine-textured soil augmented metal accumulation processes. Boxplot of geoaccumulation index (Igeo) values indicated that lead (Pb) metal had more variation in the study area. Mean Igeo values of metals in descending order are Fe (4.24) > Mn (3.08) > Cu (2.84) > Co (2.47) > Pb (1.85) > Cd (0.7) > Zn (0.58) > Ni (0.45) > Cr (0.16). Mean values of modified degree of contamination (mCdeg) (10.4) and pollution load index (PLI) (6.19) revealed high contamination with deteriorating soil quality. Combined approach of correlation, principal component (PC) and cluster analysis indicated the source of origin by describing association of metals with Fe. PC biplot showed that impact of mining was more on lowland agro-ecosystem rather than natural due to slope factor which led to clogging of pores by mining overburden mixed soil deposition from uphill as evidenced from the presence of waterlogged fallow lands. Fuzzy k-mean clustering yielded three contamination zones (CZs) of low (CZ2), moderate (CZ1) and high (CZ3) degree of contamination. The CZs-based site-specific land management plan might lead to a sustainable ecosystem through coexistence of both mining and agricultural activity by arresting contamination and restoring fallow lands. [ABSTRACT FROM AUTHOR]

Despite the difficulties in pelletizing specularite-type refractory iron ores, the utilization of these resources is indispensable for the steel industry due to the increasing need for iron. This study investigated Fe recovery from a refractory iron ore using gravity separation, reverse flotation, and two-stage magnetic separation. Tilt angle and particle size had a significant effect on the grade and recovery of concentrates in shaking table tests. Gravity concentration at optimum conditions resulted in an iron concentrate with 64.47% Fe grade and 90.73% Fe recovery. In the reverse flotation tests, the frother and depressant substantially affected the Fe grade of concentrates while the collector influenced the Fe recovery. A 90% Fe recovery with 64.69% Fe grade was obtained within optimum flotation conditions. The Fe grades were raised to >67.5% in products after the first magnetic separation. The tailings of the first magnetic separation were subjected to the second magnetic separation after microwave-assisted roasting to increase the magnetic susceptibility. In the second magnetic separation, a concentrate containing 66.06% Fe was separated from the microwave-roasted non-magnetic material with 82.23% Fe recovery. To the best of our knowledge, the microwave-roasting method has been applied to a specularite-type refractory iron ore for the first time. [ABSTRACT FROM AUTHOR]

In the process of iron ore beneficiation, a considerable amount of iron was lost to the tailings, resulting in the waste of resources and environmental pollution. In this study, an innovative technology of pre-concentration followed by suspension magnetization roasting and low-intensity magnetic separation (PSRM) was used to recover iron from iron tailings. The iron grade of the roasted feed ores was increased from 15.68% to 33.19% by pre-concentration process. Subsequently, the suspension magnetization roasting was performed to transform the weak magnetic minerals into magnetite, and magnetite concentrate was obtained via low-intensity magnetic separation. The effects of feeding rate, roasting temperature, reducing gas CO flow rate, and fluidizing gas N2 flow rate during suspension magnetization roasting were investigated, and the pilot-scale equipment was conducted for 72 h continuously under the optimum roasting conditions. The phase transformation and magnetic property variations of the minerals before and after roasting were analyzed by X-ray diffractometer (XRD) and vibrating sample magnetometer (VSM), respectively. The results showed that an iron concentrate with iron grade of 63.04% and total iron recovery of 48.40% was obtained under the optimum roasting conditions: feeding rate of 111.70 kg/h, roasting temperature of 550°C, CO flow rate of 4.0 m3/h, and N2 flow rate of 2.0 m3/h. The hematite and siderite in tailings were transformed into magnetite with an average magnetic conversion rate of 86.46%. This innovative PSRM technology provides an important reference for the resource utilization of solid waste and the recovery of iron from iron tailings. [ABSTRACT FROM AUTHOR]

We propose that neural damage in Parkinson's disease (PD) is due to dysregulation of iron utilization rather than to high iron levels per se. Iron deposits are associated with neuronal cell death in substantia nigra (SN) resulting in PD where high levels of iron in SNs are due to dysregulation of iron utilization. Cytosolic aconitase (ACO1) upon losing an iron-sulfur cluster becomes iron regulatory protein 1 (IRP1). Rotenone increases levels of IRP1 and induces PD in rats. An increase in iron leads to inactivation of IRP1. We propose a novel treatment strategy to prevent PD. Specifically in rats given rotenone by subcutaneous injections, iron, from iron carbonyl from which iron is slowly absorbed, given three times a day by gavage will keep iron levels constant in the gut whereby iron levels and iron utilization systematically can be tightly regulated. Rotenone adversely affects complex 1 iron-sulfur proteins. Iron supplementation will increase iron-sulfur cluster formation switching IRP1 to ACO1. With IRP1 levels kept constantly low, iron utilization will systematically be tightly regulated stopping dysregulation of complex 1 and the neural damage done by rotenone preventing PD. [ABSTRACT FROM AUTHOR]

The reduction roasting followed by magnetic separation process is considered to be a suitable method to treat the high-phosphorus oolitic iron ore. Currently, the dephosphorization mechanism of additives such as CaCO3, Ca(OH)2, Na2SO4, and Na2CO3 on the reduction roasting of the iron ore in which phosphorus occurs in apatite have been thoroughly studied. The effect of sodium salts (Na2CO3, NaCl and Na2SO4) on reduction roasting and magnetic separation of high-phosphorus oolitic iron ore containing phosphorus in iron oxides was investigated, and the mechanisms of sodium salts were expounded using XRD and SEM-EDS. The results show that the dephosphorization ability of sodium salts was in the order of Na2SO4> Na2CO3> NaCl>no sodium salts. Na2CO3 and Na2SO4 transferred Fe3PO7 from the iron oxides to nepheline, which upgraded the separation of iron and phosphorus. However, NaCl did not inhibit the reduction of phosphorus in the iron minerals. In addition, Na2CO3 strengthened the reduction of iron oxides. However, a small amount of wustite failed to be reduced to metallic iron with the addition of NaCl, and troilite and wustite formed hindered the reduction of iron minerals after adding Na2SO4. [ABSTRACT FROM AUTHOR]

Oolitic hematite, as a complex and refractory iron ore resource, can be efficiently utilized by magnetic roasting. In this study, to ascertain the mechanism of microwave fluidization roasting technology (MFR) for the utilization of oolitic hematite, the influence of MFR on mineral magnetism, ore microstructure, mineral phase and kinetics was further explored and clarified. The results show that under the optimized conditions of the roasting temperature 650°C for 5 min, CO concentration 30%, and ore fineness with −74 μm accounting for 90%, the saturation magnetization and saturation susceptibility of the roasted product reached the maximum respectively. Microstructure analysis shows that microcracks were generated between iron minerals and gangue minerals and gradually extended to the core of the oolitic structure with a prolongation in pretreatment time, which was particularly propitious to upgrade the iron minerals in the subsequent grinding and magnetic separation process. The isothermal kinetics shows that the apparent activation energy and pre-exponential factor of kinetic parameters in MFR process decreased gradually with a decrease in ore particle size, and the mechanism function for ore with the particle of −0.15 mm was in accordance with the one-dimensional diffusion model k = 3.805exp(−24075/RT). [ABSTRACT FROM AUTHOR]

Dry processing options, involving the use of a circulating air classifier and thermal roasting (advanced microwave-assisted magnetizing roasting), followed by magnetic separation using an Induced Roll Magnetic Separator (IRMS), were evaluated for upgrading low-grade hematite-goethite iron ore fines. The novel magnetizing roast was conducted under reducing conditions using CO/CO2 gas mixtures which converted the initial goethite-rich ore into a magnetite-rich ore. From a feed sample containing 54.5% Fe, 2.10% SiO2, 7.97% Al2O3, 0.97% TiO2 and 0.13% P with a density of 3.87 g/cm3 and 80 wt% passing 675 µm, a high-grade IRMS magnetic product of 62.0 wt% Fe was obtained with a yield of 71.6 wt% and around 82 wt% recovery of iron units. [ABSTRACT FROM AUTHOR]