Papers by Keyword: Manganese

Abstract: The possibility of joint solid-phase reduction of iron and phosphorus from ferromanganese ore has been experimentally confirmed. Solid-phase reduction was performed at a temperature of 1000°C and exposure time of 2-5 hours, in a CO atmosphere, also produced the separation of the reduction products by melting. The distribution of iron and phosphorus was studied using an electron scanning microscope. The phase analysis of the samples was studied using a Rigaku Ultima IV X-ray diffractometer. The results were processed using the "Match" software. Reducing roasting in a CO atmosphere provides a transition from the oxide phase to the metallic phase of only iron and phosphorus without loss of manganese, thus increasing the concentration of MnO oxide in the residual oxide phase of the ore.

Abstract: The paper presents the results of the effect of boron, manganese and sulfur on the microstructure and mechanical properties of pipe steel 17G1SU. It was shown that the microstructure of boron-free steel sample containing 1.4% Mn and 0.01% S consists mainly of ferrite and a small amount of perlite. Samples microalloyed by boron are represented by a dispersed ferritic-bainitic structure. A decrease in ferrite grain size from 8.7 μm, in a comparative sample without boron containing 1.4% Mn and 0.010% S to 5.8 μm in a sample of steel containing 0.006% B, 1.6% Mn and 0.011% S, shows increasing the dispersity of the ferritic-bainitic structure. A decrease in the manganese content to 1.4, sulfur to 0.004% and an increase in boron concentration to 0.0011%, despite an increase in grain size to 6.8 μm, retain a fine-grained structure. The effect of boron, manganese, and sulfur content on the microhardness of the structural phases of the studied pipe steel samples is noted. The smallest microhardness of ferrite and perlite is observed in the base sample without boron, reaching 180 and 214 HV10, respectively. The microalloying of pipe steel containing 1.6% Mn, 0.011% S with boron is accompanied by an increase in the microhardness of the bainitic phase to 314 HV10, which increases to 400 HV10 with an increase in boron concentration to 0.011%, and a decrease in the content of manganese and sulfur to 1.4 and 0.003%. In this case, the microhardness of the ferrite phase, reaching an increase to 260 HV10, is practically independent of the content of boron, manganese, and sulfur. The mechanical properties of the experimental metal rolling with a thickness of 10 mm provide the production of rolled steel of strength class X80, without heat treatment, regardless of the content of boron, manganese, and sulfur, as a result of the formation of a finely dispersed ferrite-bainitic structure.

Abstract: Peat waters were abundant in the West Tanjung Jabung Regency of Jambi Province. Peat water contains manganese metal ion concentration that exceeds the clean water quality standard. Previous studies have been conducted to reduce levels of manganese in peat water, but the results have not been significant. This study aims to reduce levels of Manganese metal in peat water using the composition of Bentonite and Biochar. The adsorption process was carried out at room temperature (29 °C) with a stirring of 200 rpm. Some parameters measured were optimum pH of adsorption, optimum contact time and the best combination between Bentonite and Biochar. Manganese ion concentration in solution was measured using atomic absorption spectroscopy (AAS). The results of this study indicate that the optimum conditions for removing manganese ion at pH 5 and contact time 40 minutes. Tests on artificial solutions using 0.2 grams of biochar showed Mn ion removal of 42.91% (C₀ = 100 mg/L, Ce = 57.09 mg/L, V = 100 mL). The best combination obtained in Bentonite: Biochar (1:2) with a mass of 0.080 gr and 0.170 gr, respectively, which able to remove 91.29% manganese ions in peat water.

Abstract: A high strength austenitic steel is expected as a structural material for cryogenic use because fcc material does not cause a cleavage fracture despite high strength. High manganese steel which is a strong candidate material of the cryogenic high strength austenitic steel was originally famous for the Hadfield steel and widely applicable in actual use. In general, an excellent cryogenic toughness of the high manganese steels is achieved by obtaining stable fcc microstructure with an adequate amount manganese which is a typical austenite former alloy. However, as addition of manganese is not effective for increasing strength, other strengthening alloying elements like carbon and chromium need to be added. In this study, an effect of alloying elements on strength and cryogenic toughness of the high manganese austenitic steel is studied.

Abstract: The aim of the study was to examine how the microstructure changes during heating of Fe-Mn-C system (step-sintering). Mixtures of powders containing 1 – 3 % Mn and 0.8 % C were prepared in Turbula TC2 mixer for 30 minutes. Before step-sintering, the dilatometric investigations were carried out, which allowed to obtain phase transformation temperatures of Fe-(1-3)Mn%-0.8%C system. Following dilatometric investigations, 4 steps – temperatures were determined dependently of isothermal sintering temperature. The commonly used industry temperatures – 1120 °C and 1250 °C – were set as target temperatures. For each of them, 4 heat steps were carried out. The procedure of investigations was as follows: samples were heated to the step temperature with heating rate 60 K/min, then isothermally sintered at step temperature for 5 min, and finally cooled to the room temperature with cooling rate ~ 66 K/min. Fe-Mn-C samples were mechanically (tensile) tested. After tensile tests, metallographic observations of the samples were performed. Based on the results obtained, the tensile strength was increasing with the increasing of the step temperature. The metallographic observation showed the microstructure evolution – with increasing the step temperature, decreasing of porosity was observed.

Abstract: Brass with Zn content up to 35 wt.% forms the single phase of α, further the Zn content above 35 wt.% will promotes the formation of β phase. The improvement of physical and mechanical properties of brass can be conducted by addition of alloying element with optimum composition. Previous research showed that the addition of Al on brass alloy accelerated the formation of β phase and changed the microstructure and mechanical properties. Some investigation have also described that the addition of Mn on brass alloy has the good effect on tensile strength, hardness, and elongation. However, the research regarding the effect of Al and Mn addition simultaneously has not been investigated. In this research, Cu-29Zn-xAl-xMn alloys were produced by gravity die casting using pure Cu, Zn and Al ingots as well as the Mn powder as the feeding materials. Addition of Al and Mn were fixed to 0.5 and 2 wt.%, respectively. The molted metal was poured into 600 °C preheated metal mold with dimension of 100x100x6 mm³. As-cast samples were homogenized at 800 °C for 2 h in a muffle furnace. Samples characterization includes chemical composition analysis, microstructure observation, tensile and hardness testing. The results described that addition of 0.58 Al (wt.%) on Cu-29Zn alloy showed the appearance of single phase (α) and tended to increase the tensile strength but decreased the elongation. On the other hand, the addition of 0.5 Al and 1.62 Mn (wt.%) simultaneously on Cu-29Zn alloy promoted the formation of second phase (β) which dispersed in the grain and along the grain boundary with irregular forms. The addition of 0.5 Al and 1.62 Mn (wt.%) on Cu-29Zn alloy simultaneously have also increased the hardness, yield and tensile strength without decreased the elongation significantly.

Abstract: Peat can be used as a natural adsorbent due to its humic acid content having various active functional groups such as carboxylates and hydroxyl groups. Peat soil samples obtained from Pelalawan district, Riau province of Indonesia were selected and their adsorption capacities were investigated using Mn(II) solution as a model solution. The raw peat samples were first prepared by drying at 110°C for 12 h. The adsorption experiment was conducted in batch test using Mn(II) solutions for 360 mins at pH of 5.2 as optimum conditions. The peat samples were analyzed using the Fourier Transform Infrared Spectroscopy, Surface Area Analysis and Scanning Electron Microscopy- Energy Dispersive Spectroscopy. The obtained adsorption data were fitted using Langmuir, Freundlich and BET isotherm models. It was found that the adsorption data followed the Langmuir isotherm model with correlation coefficients (R²) ranging between 0.9866-0.9997 and the adsorption capacities were between 11.99-22.94 mg/g.

Abstract: Manganese oxide and metallic manganese have made a long and varied contribution to the production of iron and steel through the centuries, long before Sir Robert Hadfield’s alloy manganese steel first produced in 1882. Although quite well known empirically, this contribution has sometimes been misunderstood or misrepresented.The success of some of the early so-called ‘natural steels’ was the presence of manganese oxides in the iron ores used.Manganese oxide was already used as a flux from the early days of the production of crucible steel in Asia and it now appears that it was used as a flux from the inception of the otherwise very different later European crucible steel technologies. After the introduction of crucible steel making in Britain in the 18^th century, foreign competitors believed that the reason for the success of the processes used at Sheffield was a secret flux and studies on recently discovered 18^th century crucibles in Sheffield have shown that process was indeed fluxed with manganese oxide.The function of manganese in the later European crucible steel industry has been rather overshadowed and confused historically by the very different ‘Carburet of manganese’, a strange concoction, patented by Josiah Heath in 1839 added to iron or steel to purify the metal. At the time the chemistry of the process was misunderstood and many acrimonious and inaccurate claims were made, crucially confusing the very different functions of manganese oxide and manganese metal, overshadowing the part already played by manganese oxide for almost a century previously..Finally manganese and its salts played a crucial role in the Bessemer process of steel making.

Abstract: Manganese (Mn) is one of the most serious pollutants that have negative effects on the ecosystem and water supply. The water industry faces major challenges in its treatment for contaminant and in developing an alternative product with low cost. Among various adsorbents, agriculture waste is preferred due to its biodegradability and availability. The removal of manganese (Mn) from groundwater was investigated using two different adsorbents which are banana blossom peel and floret. SEM analysis shows the formation of microporous structure for both banana blossom peels and floret while FTIR analysis confirms the functional group of strong hydroxyl group that responsible for the adsorption process. The water quality index for the groundwater sample was classified into class III which required extensive treatment. Batch adsorption experiments revealed that both adsorbents had maximum removal efficiency using 0.5 g adsorbent dosage. The banana blossom peel reduces Mn to 0.10 mg/L with 81.1% removal, while the banana blossom floret reduces Mn concentration to 0.12 mg/L with 77.7% removal.

Abstract: The article presents the theoretical basis of sulfatizing roasting in the fluidized bed of oxidic and sulphidic polymetallic raw materials: iron-manganese concretions (IMC) containing non-ferrous metals and pyrite concentrate. The results of preliminary thermodynamic and thermogravimetric studies of IMC of Pacific Ocean and pyrite are described. The results of the laboratory-scale research of sulphatizing roasting of deep-water polymetallic IMC and pyrite concentrates are given. Based on the results obtained, the conclusion is made about the prospects of using the method of preliminary sulfatization for further production of marketable concentrates of manganese and non-ferrous metals.