Manganiferous Iron Ore Research Articles

The green reductive leaching of manganiferous iron ore and Mn3O4 nanoparticles production: Kinetic modeling and comparison of various reductants

BackgroundSecuring critical metals is crucial for the transition from fossil fuels to renewable energies. In this regard, extracting metals from various sources and low-grade ores can lead to the sustainable production of metals. Manganese, as a strategic metal, can play a significant role in achieving this goal. MethodsIn this study, various reductants such as oxalic acid, citric acid, ascorbic acid, acetic acid, tannic acid, hydrogen peroxide, iron (II) sulfate, sodium thiosulfate, and DL-malic acid were used to evaluate the feasibility and comparison on the manganiferous iron ore leaching. Significant findingsDL-malic acid was chosen as the main reductant to investigate other factors because it is novel (as a reductant), eco-friendly, cost-effective, accessible, and easily storable. Therefore, more detailed studies on the dissolution of manganiferous iron ore in the presence of DL-malic acid as the reductant were carried out considering different levels of temperature, particle size, acid concentrations, and leaching time. Increasing the temperature from 298 K to 348 K notably boosted the leaching recovery from 27.00 % to 70.11 %. It was observed that decreasing the ore particle size from -212 μm to -38 μm resulted in an enhancement of leaching recovery from 57.74 % to 70.11 %. Also, adding only 250 % stoichiometry of DL-malic acid notably increased the leaching recovery to 70.11 %, compared to just 5.32 % in a reductant-free medium. It should be noted that the concentration of sulfuric acid had a direct impact on leaching recovery, increasing by 28.28 % with a concentration of 0.5 M and by 93.08 % with a concentration of 4 M. In this research work, the kinetic of the leaching process was modeled using the modified shrinking core model (MSCM). The calculated activation energy was about 33 kJ/mole, which confirmed that the mixed mechanism controlled the reaction. Mn3O4 nanoparticles were synthesized using a pregnant leach solution (PLS) and through a multi-stage co-precipitation method. In this method, hydrogen peroxide was used to modify the manganese hydroxide phase as a more eco-friendly method than other heat treatment methods. The SEM and EDX analyses revealed an average particle size of 80 nm with spherical shapes and no impurities. The XRD pattern of the synthesized nanoparticles confirmed the Mn3O4 phase composition.

Farklı indirgeyiciler kullanılarak bir manganlı demir cevherinden mangan çözündürülmesinin araştırılması

Bu çalışmada, bir manganlı demir cevherinden manganez çözünmesi indirgeyici liç yöntemiyle incelenmiştir. Sülfürik asit (H2SO4) çözeltisi içerisinde cevherden seçimli olarak manganez çözünümü için indirgeyici ajan olarak çeşitli kimyasallar kullanılmıştır. Öncelikle indirgeyici kullanılmadan seçimli mangan çözünmesi için optimum çözünme değerleri belirlenmiştir. Cevherden manganezin seçimli çözünümü hedeflendiğinden indirgeyici liç testleri, %11.54 Mn ve %2.16 Fe çözünme değerlerinin elde edildiği optimum parametreler altında (1 saat liç süresi, 300 rpm karıştırma hızı, 70 °C sıcaklık ve 1 M sülfürik asit konsantrasyonu) indirgeyici eklenerek gerçekleştirilmiştir. Çeşitli organik bileşikler kullanılarak (tartarik asit (C4H6O6), oksalik asit (C2H2O4), sitrik asit (C6H8O7), glikoz (C6H12O6), sükroz (C12H22O11) ve maleik asit (C4H4O4)) %97,46’ya varan yüksek verimlerde mangan çözünümü sağlanmıştır.

Separation of Mn and Fe from a Manganiferous Iron Ore Using Horse Dung as Reductant: A Zero Waste Approach

Separation of Mn and Fe from a Manganiferous Iron Ore Using Horse Dung as Reductant: A Zero Waste Approach

Production of Mn3O4 nanoparticles from a manganiferous iron ore via reductive leaching, precipitation, and calcination

The synthesis of Mn3O4 nanoparticles from a manganiferous iron ore through reductive leaching, precipitation, and calcination was investigated. The reductive leaching results showed that Mn (99.9%) was almost completely extracted into the leaching solution along with a substantial amount of Mg (99.9%), Al (99.5%), Ca (80%), and Fe (22.9%) under the following conditions: 30 g/L tartaric acid as a reducing agent, 1 M HCl solution, leaching temperature of 90 °C, and leaching duration of 3 h. In the first precipitation step, Fe and Al were expelled from the pregnant leach solution by the addition of NaOH prior to conducting the precipitation experiments for the production of manganese carbonate (MnCO3) particles from the purified solution. In the second precipitation step, MnCO3 particles were produced using sodium carbonate (Na2CO3) as the precipitating agent. The effects of parameters such as reaction temperature, Na2CO3 concentration, and experimental duration were investigated using the Taguchi approach. Manganse(II) was precipitated in the form of MnCO3 particles (97.4%) under the following conditions: a temperature of 30 °C, Na2CO3 concentration of 0.014 mol/L, and duration of 30 min. The precipitate was observed to have a structure similar to that of rhodochrosite (MnCO3). Thermogravimetric/differential thermal analyses were subsequently performed in three different atmospheres (air, oxygen, and nitrogen) to select a suitable atmosphere for calcination. The experimental results indicated the formation of hausmannite (Mn3O4) with a purity of 97.5% Mn3O4, 0.42% MgO, 1.66% CaO, and 0.34% FeO. The specific surface area, particle size, Curie temperature, magnetisation, coercivity, and remanence ratio of the final product obtained via 3 h of calcination at 350 °C were estimated to be 133.3 m2/g, <142.2 nm, 56 K, 10.10 Am2/kg, 0.35 T, and 0.19, respectively. The characterisation results revealed the excellent low-temperature ferromagnetic properties of the produced Mn3O4 nanoparticles.

Separation of Fe and Mn from Manganiferous Iron Ores via Reductive Acid Leaching Followed by Magnetic Separation

In this study, a process to separate manganese and iron from manganiferous iron ores by reductive acid leaching followed by magnetic separation was conceived and experimentally tested. In the leaching process, sulfuric acid was used as lixiviant and oxalic acid was used as reductant. The experimental results showed that the manganese and iron separation was optimum when the concentration of the sulfuric acid and oxalic acid were 0.75 M and 30 g/L, respectively, at a temperature of 80 °C, a solid/liquid ratio of 67 g/L, stirring speed of 400 rpm, and leaching duration of 60 min. Under this condition, 90.49% and 6.78% of Mn and Fe were dissolved, respectively, from the ore sample with a size fraction of − 106 μm. It was determined that the leaching of manganese from the ores was a second-order reaction with an activation energy (Ea) of 53.38 kJ/mol. The leaching residues obtained under the optimum condition were subjected to high-intensity wet magnetic separation tests to recover the remaining iron content. This separation process produced a concentrate containing 56.20% Fe and 1.79% Mn with iron and manganese recoveries of 56.83% and 66.73%, respectively. A magnetic separation test from an unleached ore sample was also carried out as a benchmark. To the best of our knowledge, this is the first time that a magnetic separation process was used to a residue obtained from reductive acid leaching of manganiferous iron ores to recover iron.

The exploitation of manganese-rich ‘ore’ to smelt iron in Mwenge, western Uganda, from the mid second millennium AD

By the later second millennium AD, iron production was a key economic industry in western Uganda, and Mwenge was a prominent centre of production, highly regarded for the quality of the iron it produced. Between 2007 and 2011, excavation and analysis of iron production remains from six smelting sites in Mwenge enabled the reconstruction of local smelting technologies in operation there from the fourteenth century AD onwards. Chemical and microstructural analysis of approximately 100 samples revealed that slag from some of these sites is typically characterised by a bulk chemistry high in manganese oxide (up to 12 wt%) and knebelitic olivines. Slag samples from the remainder of the sites contain low levels of manganese oxide (below 4 wt%) and fayalitic olivines. The majority of the slag samples also contain notable levels of phosphorous (1–2 wt%).This sample set provided an opportunity to discuss the impacts of manganese and phosphorous on the smelting systems in operation in Mwenge. Principal component analysis suggests that smelters in this region were deliberately combining an iron ore with a separate manganese-rich flux, rather than using a naturally manganiferous iron ore. This use of two ‘ores’ has parallels with ethnographic literature from the region, which link the use of a second ore to the production of a harder metal. It is believed that this is the first analytically documented example of the use of a manganese-rich flux in sub-Saharan Africa. In the absence of analyses of surviving iron artefacts, the data also provides an opportunity to consider the quality of the iron metal that would have been produced.

Recovery of Iron Values from Waste Manganiferous Iron Ore Fines for Pellet Making

A large volume of overburden and mine wastes is generated during the extraction and beneficiation of the low grade ores. The waste low grade manganiferous iron ore fine from southern part of India was studied for recovery of iron values. The chemical assay of the sample is 52.36% Fe, 4.75% Mn, 8.5% SiO2 and 2.82% Al2O3. The characterization study of the sample indicates the presence of microplaty hematite, goethite, pyrolusite, cryptomelane with minor amount of quartz and kaolinite. The beneficiation study of the sample does not respond to the conventional route of desliming the ground feed followed by gravity separation and magnetic separation. Therefore, an alternative technique of reduction roasting using a producer gas was attempted at different conditions. The characterization of roasted product reveals the phase transformation to magnetite and microplaty magnetite. The low intensity magnetic separation conducted with the roasted products generated at optimal condition shows that 70% concentrate having 64.5% Fe and 1.87% Mn could be produced. The high manganese in the concentrate works as an additive for making pellet with enhancement in pellet strength and drop in reducibility. Utilization of mines waste has significant impact on mineral resources and environmental hazard.

Manganiferous Iron Ore Deposit and its Thermal Metamorphism at Ta-Li-Tzu Iron Mine, Manchuria

Manganiferous Iron Ore Deposit and its Thermal Metamorphism at Ta-Li-Tzu Iron Mine, Manchuria

57Fe M�ssbauer study of pumpellyiteokhotskite-julgoldite series minerals

Fe and Mn distribution in the pumpellyite group minerals (W 8 X 4 Y 8 Z 12056-n (OH) n ) has been studied by using57Fe Mossbauer spectroscopy. The studied Fe-pumpellyites, belonging to the pumpellyite-julgoldite series, were collected from two localities; metabasites in the Tokoro belt, Hokkaido, and gabbroic sills in the Shimane Peninsula, Japan. Okhotskite, an Mn3+-dominant pumpellyite group mineral, was separated from the ores of metamorphosed manganiferous iron ore deposits in the Tokoro belt.57Fe Mossbauer spectrum of Tokoro Fe-pumpellyite is composed of two Fe2+- and two Fe3+-doublets. On the basis of the single crystal structure refinements of Al-pumpellyites published so far, doublets were assigned to Fe 2+ (IS= 1.01 andQS = 2.73 mm/s), Fe 2+ (IS = 0.97 andQS = 3.18 mm/s), Fe 3+ (IS = 0.29 andQS =1.37 mm/s) and Fe 3+ (IS = 0.36 andQS = 2.09 mm/s), whereIS is isomer shift relative to a metallic iron absorber andQS is quadrupole splitting. The Mossbauer spectrum of the Mitsu Fepumpellyite is composed of three doublets assigned to Fe 2+ (IS= 1.14 andQS = 3.20 mm/s), Fe 3+ (IS = 0.36 andQS =1.13 mm/s) and Fe 3+ (IS = 0.37 andQS= 1.93 mm/s). These assignments show strong preference of Fe3+ in the X-site. The Mossbauer spectrum of the okhotskite is composed of two doublets by Fe 3+ (IS= 0.37 andQS = 1.13 mm/s) and Fe 3+ (IS = 0.42 andQS = 2.18 mm/s). The area ratio shows that Fe 3+ :Fe 3+ ratio is 94:6. On the basis of chemical and Mossbauer analyses, Mn 3+ :Mn 3+ ratio is given as 19:81, indicating stronger Y-site preference of Mn3+ than Fe3+, what is consistent with Jahn-Teller theory. Al, Mn3+ and Fe3+ prefer the Y-site in this order.

Significance of tourmaline-rich rocks in the North Range Group of the Cuyuna Iron Range, east-central Minnesota

Concentrations of tourmaline in Early Proterozoic metasedimentary rocks of the Cuyuna iron range, east-central Minnesota, provide a basis for redefinition of the evolutionary history of the area. Manganiferous iron ore forms beds within the Early Proterozoic Trommald Formation, between thick-bedded granular iron-formation having shallow-water alepositional attributes and thin-bedded, nongranular iron-formation having deeper water attributes. These manganese-rich units were previously assumed to be sedimentary in origin. However, a reevaluation of drill core and mine samples from the Cuyuna North range has identified strata-bound tourmaline and tourmalinite, which has led to a rethinking of genetic models for the geology of the North range. We interpret the tourmaline-rich rocks of the area to be a product of submarine-hydrothermal solutions flowing along and beneath the sediment-seawater interface. This model for the depositional environment of the tourmaline is supported by previously reported mineral assemblages within the Trommald Formation that comprise aegirine; barium feldspar; manganese silicates, carbonates, and oxides; and Sr-rich barite veins.In many places, tourmaline-rich metasedimentary rocks and tourmalinites are associated locally with strata-bound sulfide deposits. At those localities, the tourmaline-rich strata are thought to be lateral equivalents of exhalative sulfide zones or genetically related subsea-floor replacements. On the basis of the occurrence of the tourmaline-rich rocks and tourmalinites, and on the associated minerals, we suggest that there is a previously unrecognized potential for sediment-hosted sulfide deposits in the Cuyuna North range.

Occurrence and genetic implications of hyalophane in manganese-rich iron-formation, Cuyuna Iron Range, Minnesota, USA

AbstractThe recent discovery of hyalophane [(K,Ba)Al1−2Si3−2O8] on the North range segment of the Early Proterozoic Cuyuna Iron Range of east-central Minnesota has shed new light on the depositional environment of these rocks. This Ba-feldspar occurs in a 10 m thick interval within the main iron-formation and typically contains between 8 and 26 mol.% celsian (BaAl2Si2O8). Its occurrence in several textural settings suggests that barium was being deposited at various stages in the paragenetic history of the iron-formation. Some of the hyalophane grains occur as the cores of micronodules, which are structurally similar to oolites or oncolites, but mineralogically are very complex. The hyalophane also occurs as rims on core grains of diverse mineral composition and as discrete phases in late crosscutting veins.Hyalophane, like other Ba-silicates, has a very restricted paragenesis. They are associated typically either with sedimentary manganese and ferromanganese deposits, or with Cu-Pb-Zn-Ba deposits. The presence of hyalophane in the Early Proterozoic manganiferous iron ores of east-central Minnesota casts doubt on the historic interpretation of these deposits as typical Superior-type sedimentary iron-formations and instead supports the view that these deposits, at least in part, consist of chemical sediments from a hydrothermal fumarolic system. The suggested involvement of a hydrothermal system is also supported by the occurrence of aegirine within the hyalophane-rich layer, and the occurrence of tourmalinites and Sr-rich baryte veins elsewhere in the Cuyuna North range.

Titrimetric, coulometric and spectrophotometric determination of manganese following perchloric acid oxidation in the presence of pyrophosphate

Manganese is oxidized quantitatively to a violet, tervalent pyrophosphate in a boiling mixture of equal parts of perchloric acid and phosphoric add. This Mn(III) can be titrated potentiometrically or coulometrically with iron(II); it can also be measured spectrophotometrically. If the titrimetric method is carried out with titanium (III) or chromium(II), iron can also be titrated immediately after the manganese. The methods were applied to a new reference sample, ISU 600 Manganiferous Iron Ore, and to manganese ore, spiegeleisen, ferromanganese, and rail steel. Manganese(II) oxalate dihydrate has been reinvestigated as a primary standard and is highly recommended.

Contributions to the mineralogy of Egyptian manganese deposits

Pyrolusite and manganite are the most abundant manganese minerals; psilomelane and cryptomelane are less common, and ramsdellite is present only in minute quantities. The deposits of the Eastern Desert (mainly fissure fillings in Miocene sedimentary rocks) contain less goethite and hematite than those of west-central Sinai, which occur as bands and lenses in Carboniferous dolomitic limestone and are the most important source of manganese and manganiferous iron ores in Egypt.

Production of Spiegeleisen from Open-Hearth Slag In an Experimental Blast Furnace

A three ton per day blast furnace using blast temperatures up to 2200°F was operated to recover manganese from open-hearth slag and manganiferous iron ore. The spiegel product containing 12 to 24 pct Mn was blown in a basic converter to high manganese oxide slag as described in the paper which follows this one.

Manganese in the Montreal Mine, Montreal, Wisconsin

The mode of occurrence of manganese and its associated minerals in the manganiferous iron ore bodies of the Montreal Mine is described. It is believed that most of the manganese was contributed to the iron ore bodies by solutions of magmatic origin ascending along transverse or oblique faults from an unknown, but probably granitic, source. The manganese was apparently first deposited as rhodochrosite, subsequently altered to manganese oxides and hydroxides by calcium chloride waters which are thought to have been of juvenile derivation.

I.—On the estimation of manganese in spiegeleisen, and of manganese and iron in manganiferous iron ores

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