• Resources Recycling
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• v.9 no.4
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• pp.44-49
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• 2000

Among dusts which were generated in AOD process producing a medium-low carbon ferromanganese, the dust collected in bag filter contained manganese about 63% and its phase was $Mn_3$$O_4$. the maximum extraction of Mn by nitric acid is about 67% because of remaining amorphous $MnO_2$. Therefore this research investigated reducibility of the activated charcoal in Mn extraction from the dust. Addition of charcoal over 10% of pulp density made possible Mn extraction of 90% at $70^{\circ}C$, 0.5N $HNO_3$. To convert $Mn_3$$O_4$ to MnO by reducing roasting, the minimum mixture ratio of activated charcoal was 5% in $750^{\circ}C$, 1 hour. Extraction of Mn from the reduced dust was over 99% with nitric acid at $25^{\circ}C$, 6N $HNO_3$, pulp density 150 g/l§.

• Resources Recycling
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• v.21 no.3
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• pp.21-27
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• 2012

In order to make high-purity ferro-manganese from $Mn_3O_4$ dust, the application of aluminothermy process to the reduction of $Mn_3O_4$ dust was investigated in previous work. The result showed the fact that can be obtained high purity ferro-manganese which have over about 93% of manganese content and lower impurities such as C, P, S than those of KS D3712 specification. The addition of silicon powder instead of aluminum powder was investigated as reductant in the thermite reaction process of $Mn_3O_4$ dust in this work because its production cost is lower than that of aluminum powder. In case of addition of silicon powder only as reductant, the experimental result showed the unstable ignition and no thermite reaction of mixture, but in case of simultaneous addition of silicon and aluminum powders as reductant, showed the fact that can be obtained high purity ferro-manganese which have much low content of impurities such as C, P, S component.

• Resources Recycling
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• v.11 no.1
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• pp.3-8
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• 2002

In order to make the high purity Mn$_3$O$_4$powder for the raw material of soft ferrite, Mn is extracted from the dust and the extracted solution is refined. The dust is generated in producing a medium-low carbon ferromanganese and contains 90% Mn$_3$O$_4$. Mn$_3$O$_4$in the dust was reduced into MnO by roasting with charcoal. Injection of the 180g/L of the reduced dust into 4N HCI solution increased pH of the leaching solution higher than 5 and then a ferric hydroxide was precipitated. Because the ferric hydroxide co-precipitates with Si ion etc, Fe and Si ion was removed from the solution and the about 10% Mn solution was obtained. The solution was diluted with water to Mn-15000 ppm and $NH_4$F was injected into the diluted solution at $70^{\circ}C$ to the F-3000 ppm. As a result, Ca ion is precipitated as $CaF_2$and the residual concentration of Ca was 14 ppm. Injection of the equivalent (NH$1.5M_4$)$_2$$CO_3$solution as 2 L/min at $25^{\circ}C$ into the above solution precipitated a fine and high purity $MnCO_3$powder. The deposition was filtrated and roasted at $1000^{\circ}C$ for 2 hours. As a result, $MnCO_3$powder is converted into $Mn_3$$O_4$powder and it had $8.2\mu$m of median size. The final production is above 99% $Mn_3$$O_4$powder and it satisfied the requirement of high purity $Mn_3$$O_4$powder for a raw material of soft ferrite.

• Journal of the Korean Applied Science and Technology
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• v.28 no.2
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• pp.135-139
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• 2011

In order to make high-purity ferro-manganese from $Mn_3O_4$ waste dust, the application of aluminothermite process to the reduction of the waste dust was investigated. The mixture from $Mn_3O_4$ dust as metallic source and Al metal powder as the reductant ignited, and reduced with an extremely intense exothermic reaction. The rapid propagation of the aluminothermite reaction occurred spontaneously and stably by ignition of the mixture. The Manganese having some alloy elements emerged as liquids due to the high temperatures reached up to about $2,500^{\circ}C$ and separated from the liquid by their differences of specific gravity. The result of thermite reaction showed the fact that can be obtained high purity ferro-manganese which have over about 90% of manganese content and lower impurities such as C, P, S than those of KS D3712 specification. The recovery of manganese from $Mn_3O_4$ dust was lower level of about 65% than about 75% from manganese ore by electric furnace process, that is due to spatter loss because of its extremely intense thermite reaction. But it will be improved by the process designed to provide CaO as the cooler or to use the Al metal powder having larger particle size distribution.

• Resources Recycling
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• v.9 no.1
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• pp.21-26
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• 2000

Extraction of manganese was investigated with nitric acid from the dust which was generated in the AOD process producing a medium-low carbon ferromanganese from a high carbon ferromanganese. Content of manganese oxide in the dust was about 90%, and phase of it was confirmed as $Mn_3O_4$, The $Mn_3O_4$ particles was agglomerated as spherical shape, and had a lot of pore and crack inside. Maximum recovery of Mn from the sample in the leaching step was about 67% and residue was the amorphous $MnO_2$. The extraction of Mn increased with increasing temperature, but decreased in proportion to concentration of nitric acid. The extraction rate was in good agreement with the pore diffusion model.

• Resources Recycling
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• v.8 no.3
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• pp.9-17
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• 1999

The study investrgated the properti es of lh$\xi$ dust~ from felToalloy manufacture, The chemical composition, composItron material, particle size and shapes of the bulk dust, sized dust and magnetically separated dust were llivestigated. As the result, we s suppose that the dust from HLgh Carbon Fenomauganesc Manufacturing Process is not sufficient as soource material of Mn because of the low Mn conteut (13.5%) aud complicated composition material The dust from Bag Filter of AOD Process is m mainly made up of $0.2~2\mu\textrm{m}$ $Mn_3O_4$ (Hausmatmite) particle in spherical shape and the Mn content is 63.1%. The dust from Cooler of AOD Process is mainly made up of coarse $Ca(OH)_2$ Mn, $Fe_yO_2$ $SiO_2$ and fine $Mn_3O_1$.

• Resources Recycling
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• v.12 no.1
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• pp.33-40
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• 2003

Mn was extracted by using a nitric acid from the reduced ferromanganese dust and the basic experiments were taken to refine the manganese nitrate solution by means of precipitation of Ca, Mg oxalate. The dust was generated in AOD process producing a medium-low carbon ferromanganese and collected in the bag filter. Manganese oxide content in the dust was about 90% and its phase was confirmed as $Mn_3$$O_4$. $Mn_3$$O_4$ in the dust was reduced to MnO by roasting with activated charcoal. The main impurities in the extracted solution prepared by leaching the reduced dust with nitric acid were Na, K, Fe, Si, Ca, Mg etc. Among them, Fe was removed by controlling pH of the solution more than 4 and precipitating $Fe(OH)_3$, simultaneously silicious material solved in the solution was removed by co-precipitation with the ferric hydroxide. Addition of 150 g reduced dust into 4N HNO3 solution 1$\ell$ was appropriate to control the pH of the solution to pH 4. To differ greatly the solubilities of manganese oxalate and calcium or magnesium oxalate in a solution containing a high concentration of Mn, pH of 4 or less and addition of ($NH_4$)$_2$$C_2$$O_4$ in equivalent with Ca and Mg are recommended. At this time, the higher temperature was the shorter the precipitation reaction time was needed.

• Journal of the Korean Applied Science and Technology
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• v.30 no.1
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• pp.71-77
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• 2013

Aluminium powder as reductant in aluminothermy process needs a fine particle size under 200 mesh, but it is not easy economically to make that because of its high ductility and powder production cost. In order to reduce the production cost of fine aluminum powder as reductant of $Mn_3O_4$ waste dust, therefore, the properties of aluminium alloy powder were investigated. Aluminium alloy ingot containing large amount of manganese can be crushed easily because of its intermetallic compounds having brittle properties. The manganese is also main element in ferro-manganese. We can obtain economically Al-15%Mn alloy powder by mechanical comminution process. And the result of thermite reaction using Al-15% Mn alloy powder instead of pure Al powder showed the fact that can be obtained the ferro-manganese which have a high purity in case of using pure aluminium powder as reductant. The recovery of manganese from $Mn_3O_4$ waste dust with Al-15%Mn alloy powder was higher level of about 70% than about 65% in case of using aluminium powder, that is due to lower spatter loss.

• Biomedical Science Letters
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• v.24 no.4
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• pp.357-364
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• 2018

Manganese (Mn) is used as main materials in various chemical processes of industry, but it suggested that Mn brings about its toxicant by fume or dust through respiratory system and skin barrier. Mn toxicant induces the loss of mental health and life quality by cerebrovascular and skin diseases. Nevertheless, it lefts much unknown on the mechanism and the effectively therapeutic methods about Mn toxicant. Therefore, this study was evaluated the cytotoxicity induced by manganese dioxide ($MnO_2$) in cultured NIH3T3 fibroblasts, and also, the correlation between $MnO_2$-induced cytotoxicity and oxidative stress was examined. While, the effect of Eclipta prostrata L. (EP) extract belong to Compositae was assessed against $MnO_2$-induced cytotoxicity in the view of antioxidative effect for searching the natural resources mitigating or preventing the $MnO_2$-induced cytotoxicity. In this study, $MnO_2$-induced cytotoxicity was revealed as mid-toxic by Borenfreud and Puerner's toxic criteria, and catalase (CAT), an antioxidant prevented $MnO_2$-induced cytotoxicity by the remarkable increase of cell viability in these cultures. While, in the protective effect of EP extract on $MnO_2$-induced cytotoxicity, EP extract effectively prevented the cytotoxicity induced by $MnO_2$ via antioxidative effects such as xanthine oxidase (XO) inhibitory ability and DPPH-radical scavenging ability. From the above results, EP extract showed the effective prevention against $MnO_2$-induced cytotoxicity correlated with oxidative stress by antioxidative effects. Conclusively, this study may be useful to research or development the alternatively therapeutic agent from natural resources like EP extract for the treatment of diseases resulted in oxidative stress.

• Resources Recycling
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• v.32 no.1
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• pp.33-41
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• 2023

Herein, we selectively recovered Zn and produced ZnSO₄ from electric arc furnace dust using a hydrometallurgical process. The analysis of the properties of the electric arc furnace dust revealed that the Fe content (9.9%) was relatively low while the Mn content (19%) was high as compared to the composition of general dust. Therefore, an appropriate hydrometallurgical process was designed based on the properties of the raw materials. In the leaching process involving the use of 1.6 M sulfuric acid and 20% solid-liquid ratio at 60℃ for 1 h, 85% of the Zn and Mn got dissolved while the Fe was not leached. To selectively recover Zn, a solvent extraction process using D2EHPA as the extractant was chosen, and 99% of the Zn was extracted using 0.8 M D2EHPA with 32% saponification and an O/A ratio of 2 using counter-current 3-stage extraction. Mn was entirely scrubbed with an aqueous sulfuric acid solution of pH 1.5. Finally, Zn was concentrated and stripped using 1.5 M sulfuric acid at an O/A ratio of 4 using counter-current 4-stage stripping. The stripping solution contained 40 g/L of Zn, and 99.9% of ZnSO₄∙H₂O was obtained by vacuum distillation.