scholarly journals Reduction and Dissolution Behaviour of Manganese Slag in the Ferromanganese Process

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 97 ◽  
Author(s):  
Xiang Li ◽  
Kai Tang ◽  
Merete Tangstad
Keyword(s):  
Electron Microscopy ◽  
South Africa ◽  
Scanning Electron Microscopy ◽  
Liquidus Temperature ◽  
Reduction Rate ◽  
Manganese Ore ◽  
Thermo Gravimetric ◽  
Dissolution Behaviour ◽  
Manganese Slag ◽  
Scanning Electron

The reduction and liquidus behaviour of manganese slag with different basicities were studied in non-isothermal experiments in the temperature range of 1400–1500 °C. Certain amounts of quartz were added to Assmang ore (South Africa), and lime was added to Comilog ore (Gabon), to adjust the charge basicity to 0.5, 0.8 and 1.2. The extent of manganese ore reduction as a function temperature were determined by thermo-gravimetric (TG) balance. Morphology of ores and its change in the course of reduction was examined by scanning electron microscopy (SEM). The results show that the reduction rate of Assmang slag decreases with decreasing basicity, as the liquidus temperature of slag decreases. When spherical MnO phase is present, the activity of MnO is high, and the reduction rate is rapid. Comilog slags show a much higher reduction rate than Assmang slags. The activation energies of MnO reduction between 1400 to 1500 °C are estimated in this study and found to be 230 kJ/mol for Assmang charges and 470 kJ/mol for Comilog charges. The dissolution behaviours of Assmang and Comilog slags were also studied by FactSage simulation and verified by experiments.

scholarly journals On cestode and digenean parasites of Clarias gariepinus (Burchell, 1822) from the Rietvlei Dam, South Africa

2006 ◽  
Vol 73 (2) ◽  
Author(s):  
M. Barson ◽  
A. Avenant-Oldewage
Keyword(s):  
Electron Microscopy ◽  
South Africa ◽  
Scanning Electron Microscopy ◽  
New Record ◽  
Histological Analysis ◽  
Clarias Gariepinus ◽  
Host Fish ◽  
Mean Intensity ◽  
Anterior Intestine ◽  
Scanning Electron

Sharptooth catfish, Clarias gariepinus, from the Rietvlei Dam near Pretoria, South Africa were examined for internal platyhelminth parasites. Two adult cestodes, Polyonchobothrium clarias (stomach) (prev alence 71 %, mean intensity = 5, n = 7) and Proteocephalus glanduliger (anterior intestine) (prevalence 14 %, mean intensity = 2, n = 7), were found in the gut while metacercariae of one larval digenean, Ornithodiplostomum sp. (prevalence 14 %, mean intensity = 140, n = 7), were found encysted in the muscles. The morphology of these species, based on light and scanning electron microscopy as well as histological analysis, and how they differ from previously described specimens, are discussed. Ornithodiplostomum is a new record in southern Africa. Infection levels of the host fish were mild compared to records from previous surveys.

Purification of SWNTs Using Microwave Heating

2001 ◽  
Vol 706 ◽  
Author(s):  
Avetik R. Harutyunyan ◽  
Bhabendra K. Pradhan ◽  
Gamini U. Sumanasekera ◽  
Jiping Chang ◽  
Gugang Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Microwave Heating ◽  
Acid Treatment ◽  
Carbon Coating ◽  
Single Wall Carbon Nanotubes ◽  
Metal Catalyst ◽  
Thermo Gravimetric ◽  
Mild Acid ◽  
Scanning Electron

AbstractA new method for purifying single wall carbon nanotubes (SWNTs) using microwave heating is developed. The microwaves couple to the residual metal catalyst, raising significantly the local temperature leading to both the oxidation and rupturing of the carbon passivation layer over the metal catalyst particles and sintering. With this protective carbon coating weakened or removed, a mild acid treatment in HCl is then sufficient to remove most of the metal in the sample, leaving the nanotubes in tact. Results from transmission and scanning electron microscopy (TEM & SEM), Raman spectroscopy and thermo-gravimetric studies are discussed.

Redescription of Lamproglena Clariae Fryer, 1956 (Copepoda, Lernaeidae), With Notes On Its Occurrence and Distribution

Crustaceana ◽  
1996 ◽  
Vol 69 (4) ◽  
pp. 509-523 ◽  
Author(s):  
A. Avenant-Oldewage ◽  
Hazel M. Marx
Keyword(s):  
Electron Microscopy ◽  
South Africa ◽  
Scanning Electron Microscopy ◽  
National Park ◽  
Kruger National Park ◽  
Gill Parasite ◽  
Morphological Findings ◽  
Olifants River ◽  
First Time ◽  
Scanning Electron

AbstractThe morphology of the gill parasite Lamproglena clariae Fryer, 1956, from the Olifants River, Kruger National Park, South Africa, was studied with the aid of light and scanning electron microscopy. Ultrastructural details of all appendages are given as well as a table and map with information on the occurrence and distribution of L. clariae in Africa. Important morphological findings include: the observation of only one claw on the maxilla; first time findings and descriptions of the nuchal organ, upper and lower lips, the fifth pair of legs and circular openings on all appendages.

scholarly journals Mineralogical Characterization of Manganese Oxide Minerals of the Devonian Xialei Manganese Deposit

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1243
Author(s):  
Sida Niu ◽  
Liqun Zhao ◽  
Xiaoju Lin ◽  
Tong Chen ◽  
Yingchao Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Manganese Oxide ◽  
Spherical Particles ◽  
Manganese Ore ◽  
Manganese Deposit ◽  
Mineralogical Characterization ◽  
Mn Oxide ◽  
Oxide Minerals ◽  
Scanning Electron

The Guangxi Zhuang Autonomous Region is an important manganese ore district in Southwest China, with manganese ore resource reserves accounting for 23% of the total manganese ore resource reserves in China. The Xialei manganese deposit (Daxin County, Guangxi) is the first super-large manganese deposit discovered in China. The Mn oxide in the supergene oxidation zone of the Xialei deposit was characterized using scanning electron microscopy (SEM), energy spectrometer (EDS), transmission electron microscopy (TEM, HRTEM), and X-ray diffraction analysis (XRD). The Mn oxides have a gray-black/steel-gray color, a semi-metallic-earthy luster, and appear as oolitic, pisolitic, banded, massive, and cellular textures. Scanning electron microscopy images show that the manganese oxide minerals are present as fine-spherical particles with an earthy surface. TEM and HRTEM indicate the presence of oriented bundled and staggered nanorods, and nanopores between the crystals. The Mn oxide ore can be classified into two textural types: (1) oolitic and pisolitic (often with annuli) Mn oxide, and (2) massive Mn oxide. Pyrolusite, cryptomelane, and hollandite are the main Mn oxide minerals. The potassium contents of cryptomelane and pyrolusite are discussed. The unit cell parameters of pyrolusite are refined.

New phytoptids (Eriophyoidea, Phytoptidae) from southern African endemic dicotyledons: description of two new species of Solenocristus n. g. and updated key to world genera of the tribe Sierraphytoptini

2018 ◽  
Vol 23 (7) ◽  
pp. 1290 ◽  
Author(s):  
Philipp Chetverikov ◽  
Charnie Craemer ◽  
Stefan Neser ◽  
Sarah Zukoff
Keyword(s):  
Electron Microscopy ◽  
South Africa ◽  
Scanning Electron Microscopy ◽  
New Species ◽  
Western Cape ◽  
The World ◽  
Two New Species ◽  
Temperature Scanning ◽  
Scanning Electron ◽  
Conventional Light Microscopy

A new phytoptid genus and two new species, Solenocristus karooensis n. g. & n. sp. and S. searsius n. sp. (Phytoptidae, Sierraphytoptinae, Sierraphytoptini), were collected in the Eastern and Western Cape provinces of South Africa, from southern African endemic dicotyledonous trees Schotia afra (Fabaceae) and Searsia lucida (Anacardiaceae) respectively. They are described and illustrated with the aid of conventional light microscopy and low temperature scanning electron microscopy. Females of both new species possess a distinct pregenital plate divided into two parts by a subcuticular medial ridge. Additionally, in S. karooensis n. sp. the movable digit of the male chelicerae varies in length: among six observed males, three males had a movable digit (md) twice shorter than the fixed digit (fd), in one male it was slightly shorter than fd and in the remaining two males md and fd were of the same length. An updated key to the world genera of the tribe Sierraphytoptini is given. The key incorporates data on seven sierraphytoptine genera including three genera (Neoprothrix Reis & Navia, Solenoplatilobus Chetverikov & Craemer and Solenocristus n. g.) which were described since the last generic key of Eriophyoidea by Amrine et al. (2003) was published.

scholarly journals Studies on the genus Setaria Viborg, 1795 in South Africa. III. Setaria thwaitei Mönnig, 1933

2004 ◽  
Vol 71 (2) ◽  
Author(s):  
R. Watermeyer ◽  
J. Boomker ◽  
J.F. Putterill
Keyword(s):  
Electron Microscopy ◽  
South Africa ◽  
Scanning Electron Microscopy ◽  
Original Description ◽  
Valid Species ◽  
The North ◽  
Roan Antelope ◽  
Hippotragus Equinus ◽  
North And South ◽  
Scanning Electron

Mönnig (1933) described Setaria thwaitei from a sable antelope, Hippotragus niger, the type host, as well as from roan antelope, Hippotragus equinus, and waterbuck, Kobus ellipsiprymnus. Yeh (1959) considered Setaria thwaitei to be synonym of Setaria hornbyi. Material collected from roan antelopes, sable antelopes and gemsbuck, Oryx gazella, from several localities in the north and south of South Africa, together with Mönnig's (1933) material, were re-examined. Measurements of the adult worms obtained in this study were compared with those in the original description of the species. Scanning electron microscopy of the anterior and posterior regions of the female worms confirmed S. thwaitei as a valid species.

scholarly journals Recognition of a New Cr(VI)-Reducing Strain and Study of the Potential Capacity for Reduction of Cr(VI) of the Strain

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Chunyong Wang ◽  
Yanshan Cui
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Reduction Rate ◽  
High Tolerance ◽  
Treatment Results ◽  
Sem Images ◽  
Bacterial Surface ◽  
Potential Capacity ◽  
Optimum Ph ◽  
Scanning Electron

The biotransformation of hexavalent chromium [Cr(VI)] via Cr(VI)-reducing microorganisms is considered an ecofriendly approach to detoxify Cr(VI). A new Cr(VI)-reducing bacterium named Microbacterium sp. QH-2 was isolated in this study. Scanning electron microscopy (SEM) images showed protrusions on the bacterial surface of strain QH-2 after an 18 h incubation in media under 10 mM Cr(VI) treatment. Results of the experiments on the capacity of reducing Cr(VI) indicated that strain QH-2 could reduce 100% Cr(VI) less than 48-96 h. When media with 4 mM Cr(VI) were incubated, the fastest reduction rate of strain QH-2 could come up to 2.17 mg/L Cr(VI) h−1. Furthermore, strain QH-2 could reduce Cr(VI) over the pH between 7 and 10. The optimum pH to reduce Cr(VI) by strain QH-2 was 9. Strain QH-2 also exhibited a relatively high tolerance even to 20 mM Cr(VI). These results declared that strain QH-2 had the potential to detoxify Cr(VI) in the Cr(VI)-contaminated soil or effluent.

scholarly journals Nematode parasites of Clarias gariepinus (Burchell, 1822) from the Rietvlei Dam, South Africa

2006 ◽  
Vol 73 (2) ◽  
Author(s):  
M. Barson ◽  
A. Avenant-Oldewage
Keyword(s):  
Electron Microscopy ◽  
South Africa ◽  
Scanning Electron Microscopy ◽  
Abdominal Cavity ◽  
Clarias Gariepinus ◽  
Infection Rates ◽  
Nematode Parasites ◽  
High Prevalence ◽  
Scanning Electron

Catfish, Clarias gariepinus, from the Rietvlei Dam near Pretoria, South Africa were examined for nem atode parasites. Two species, Procamallanus laeviconchus in the stomach and Contracaecum spp. larvae in the abdominal cavity, were found. The morphology of these species, based on light and scanning electron microscopy, and how they compare with previously described specimens are discussed. Infection rates were mild compared to previous surveys although Contracaecum spp. had a high prevalence of 86 %.

scholarly journals Two new species of Mallomonas (Chrysophyceae: Synurales): Mallomonas temonis and Mallomonas divida

Phytotaxa ◽  
2013 ◽  
Vol 87 (1) ◽  
pp. 11 ◽  
Author(s):  
YVONNE NĚMCOVÁ ◽  
JANA KREIDLOVÁ
Keyword(s):  
Electron Microscopy ◽  
South Africa ◽  
Scanning Electron Microscopy ◽  
New Species ◽  
Scale Morphology ◽  
Table Mountain ◽  
Silica Scale ◽  
Two New Species ◽  
Means Of Transmission ◽  
Scanning Electron

This paper describes two new species of Mallomonas. Mallomonas temonis was identified in the Table Mountain Plateau, South Africa; Mallomonas divida was identified in Aquitaine, France. The descriptions are based on silica-scale morphology studied by means of transmission and scanning electron microscopy. Mallomonas temonis belongs to the section Heterospinae. A scale is surrounded by a submarginal rib connected at lateral parts by a strong, more or less transversal rib. Mallomonas divida belongs to the section Torquatae. The shield of scales is covered by regularly arranged, delicate papillae and marked by one or several rows of more distinctive papillae.

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