• Resources Recycling
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• v.9 no.1
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• pp.63-69
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• 2000

Ferromanganese dust is an oxide substance of Mn. If imprities are removed and oxidation degree is controlled, the dust can be recycled for soft ferrite materials. The ferromanganese dust contained about 7 kinds of impurities, expecially about 9000 ppm of $SiO_2$ contents of the ferromanganese dust from 9000 ppm to under 500 ppm by fritting method. The $SiO_2$ in ferromanganese dust can be converted into water soluble compounds by alkali fritting and removed by water leaching. KOH and NaOH were used. The most effective conditions to get rid of $SiO_2$ from the dust are that the weight ratio of alkali to ferromanganese dust is 1.75 and fritting is run at $550^{\circ}C$ for 1 hour.

• Korean Journal of Metals and Materials
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• v.48 no.2
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• pp.154-162
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• 2010

A fundamental study of the distillation behavior of ferromanganese alloy melts was carried out at 1773 K and 0.1333 kPa (=1 Torr). During the distillation of ferromanganese alloy melts under reduced pressure, manganese vaporizes preferentially to phosphorus and other solute elements. High purity manganese metal with a very low content of solute elements can be obtained by distillation of ferromanganese alloy melts. The evaporation of manganese is suppressed as the carbon content of ferromanganese alloy melt increases due to the decrease of activity and vapor pressure of the manganese. When the carbon content of ferromanganese alloy melt is high, melt droplets are ejected from the bath, especially in the early stages of the distillation, and the solute elements in the splashed droplets contaminate the condensed material. The ejection of melt droplets is presumed to be caused by the increase of melting temperature and viscosity of the surface layer of melt due to the enrichment of solute elements such as carbon and iron.

• 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.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.23-30
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• 2015

The properties of dust collected from electric arc furnace of ferro manganese production units was investigated, and also the metallic manganese was recovered from the dust by aluminothermy process. The ferromanganese dust collected from electric arc furnace contained about 15% of manganese oxide ($Mn_3O_4$) and 9% of carbon as the contaminant, and have a 5um of 50% median diameter and irregular particle shape. The carbon contaminant in the dust could be reduced until about 0.1~0.5% level by roasting in the air at a temperature of 600~900C for 60minutes. The recovery of manganese could not be carried out using only ferromanganese dust from electric arc furnace by aluminothermy process, but the ferromanganese which contained manganese of about 92% and iron of about 5% could be obtained from the mixture of ferromanganese dusts from electric arc furnace and converter. The best mixing condition of dust fixed at electric arc furnace dust / converter dust ratio of 1:9 and 2:8, and the mixing rato of 3:7 or more could not separated the metal and slag from the reactant after aluminothermy reaction.

• Ocean and Polar Research
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• v.25 no.2
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• pp.227-235
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• 2003

In August 1998, during the resumed fourth session of the Authority, the delegation of the Russian Federation reminded the Assembly that, in addition to polymetallic nodules, other mineral resources existed in the Area, including polymetallic sulphides and cobalt crusts, and requested the Authority to adopt rules, regulations and procedures for exploration for such resources. Pursuant to article 162, para. 2(o)(ii), of the 1982 UNCLOS, such rules, regulations and procedures are to be adopted within three years of the date of such a request. This article reviewed the 'Draft Rules and Regulations for the Exploration and Exploitation of Sea-Floor Massive Sulphides and Cobat-rich Ferromanganese Crusts in the Area' by ISA in 2001, and the 'Madang Guideline for Offshore Mineral Policy' written in 1999 in respect of the international trends of polymetallic sulphides and cobalt crusts. Issues for size of mining area and relinquishment, application of the site-banking system, procedure for dealing with overlapping claims and precautionary approach etc. for the establishment of the norm of polymetallic sulphides and cobalt crusts are reviewed as consideration factors.

• Journal of the Korean Chemical Society
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• v.29 no.4
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• pp.390-396
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• 1985

The manganese was extracted from ferromanganese slag with 6N ammonium sulfate and purified with ammonium sulfide. The current efficiencies were substantially increased when small amounts of selenious acid is used as an additive. Stainless steel was used as cathodic electrode and lead (+1% Ag) as anodic electrode. The effects of several variables were investigated, and the optimum conditions were found to be; 40g/l Mn in electrolyte at pH 7.0 with 1$20g/l (NH_4)_2SO_4$, Cathode current density 60mA/cm$^2$, Current efficiency 90% and up at the temperature about $25^{\circ}C.$ The metal produced has been consistantly of high quality.

• Journal of Ocean Engineering and Technology
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• v.32 no.4
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• pp.287-295
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• 2018

This paper presents the results of an exploration of the ferromanganese crusts of Western Pacific Seamount registered by the Korean government. This area has been surveyed with a deep-sea camera and crust samples have been acquired by deep-sea dredging since 2013. On October 18-19, 2017, a united research team from KIOST and KRISO explored two blocks, OSM11 and OSM07, on the seamount using Hemire ROV. A precise survey was conducted on the ferromanganese crusts and sediments covering the slope/top of OSM11 and the middle flat area of OSM07. Rock samples were collected with precise positioning, and HD videos were recorded for 7 hours. This paper discusses the technical issues of this exploration in terms of (1) how to deal with an emergency situation during an electric power blackout, (2) the improvement of the thruster power by adding cooling plugs to the housings of the thruster amplifiers, (3) the relative motion of the depressor by changing the fixing method of the cable terminator, which affects the service life of the cable, (4) a sampling technique for the steep slope of the seamount, (5) integrated navigation under a USBL blackout, and (6) a 3-dimensional image mosaic for visualizing the distribution state of the crusts.

• 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§.

• 한국해양학회지
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• v.22 no.3
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• pp.168-178
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• 1987

A study on the mineralogy and internal features have been carried out on a sample of ferromanganese crust from a Central Pacific seamout. The distribution of manganese mineral vernadite($\delta$-MnO$\sub$2/)in the different layers indicates typical hydrogenous origin under a continuous change of growth conditions during crustal firmation. Various internal structures are discerned within the crust which may be attributed to different growth conditions. The growth structure changes and the distinct break in the formation of the crust at about 2 depth are assumed to be the results of Miocene to mid-Pleistocene global palaeoceanographic events.

• Resources Recycling
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• v.24 no.6
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• pp.24-30
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• 2015

The sulfuric acid leaching of ferromanganese dust was studied. The effect of acid concentration, reaction temperature, stirring rate, particle size and solid to liquid ratio on Mn and Fe extraction in the solution were investigated. It was found that the leaching rate of Mn and Fe increased with increasing reaction temperature and sulfuric acid concentration. Examination of data by shrinking core model suggested that the leaching rate is controlled by chemical reaction at the surface of particle. The activation energy for the leaching reaction of Mn and Fe were calculated to be 79.55 kJ/mol and 77.48 kJ/mol, respectively.