Factors Affecting Radium Removal Using Mixed Iron-Manganese Oxides

1993 ◽  
Vol 85 (10) ◽  
pp. 114-121 ◽  
Author(s):  
Henry V. Mott ◽  
Sarabjit Singh ◽  
Venkateshwer R. Kondapally
Keyword(s):  
Manganese Oxides ◽  
Factors Affecting ◽  
Iron Manganese

The Enrichment Regularity of Rare Earth Elements and Resource Characteristics in Polymetallic Nodules/Crusts

2011 ◽  
Vol 284-286 ◽  
pp. 2497-2500
Author(s):  
Lian Feng Gao ◽  
Peng Zhang ◽  
Ying Zhang ◽  
Zhen Guo Zhang ◽  
Chang Shui Liu
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Manganese Oxides ◽  
Average Content ◽  
Cobalt Nickel ◽  
Mineral Development ◽  
Polymetallic Nodules ◽  
The Pacific ◽  
Resource Characteristics ◽  
Iron Manganese

Polymetallic nodules/crusts are one of the most important mineral deposits in the ocean, in which iron, manganese, copper, cobalt, nickel and other metals are rich, and rare earth elements are rich, too. In this study, the contents of 11 rare earth samples in polymetallic nodules/crusts from the Pacific, Atlantic, Indian Ocean and north of the South China Sea are analyzed. The average content of rare earth in polymetallic nodules/crusts is 1265.57×10-6, the average content of nodules is 1096.96×10-6, and the average content of crust is 1623.88×10-6. The enrichment of rare earth elements is controlled by iron and manganese oxides and clay minerals in nodules/crusts, which could absorb rare earth elements from seawater and sediment. Ce elements are highly enriched, making polymetallic nodules/crusts become the first used rare earth elements in mineral development.

scholarly journals Fischer-Tropsch Synthesis over Iron Manganese Catalysts: Effect of Preparation and Operating Conditions on Catalyst Performance

2009 ◽  
Vol 2009 ◽  
pp. 1-12 ◽  
Author(s):  
Ali A. Mirzaei ◽  
Samaneh Vahid ◽  
Mostafa Feyzi
Keyword(s):  
Synthesis Gas ◽  
Manganese Oxides ◽  
Active Catalyst ◽  
Catalytic Performance ◽  
Operating Conditions ◽  
Light Olefins ◽  
Solution Ph ◽  
Molar Ratios ◽  
Operation Conditions ◽  
Iron Manganese

Iron manganese oxides are prepared using a coprecipitation procedure and studied for the conversion of synthesis gas to light olefins and hydrocarbons. In particular, the effect of a range of preparation variables such as [Fe]/[Mn] molar ratios of the precipitation solution, pH of precipitation, temperature of precipitation, and precipitate aging times was investigated in detail. The results are interpreted in terms of the structure of the active catalyst and it has been generally concluded that the calcined catalyst (at 650 for 6 hours) containing 50%Fe/50%Mn-on molar basis which is the most active catalyst for the conversion of synthesis gas to light olefins. The effects of different promoters and supports with loading of optimum support on the catalytic performance of catalysts are also studied. It was found that the catalyst containing 50%Fe/50%Mn/5 wt.% is an optimum-modified catalyst. The catalytic performance of optimal catalyst has been studied in operation conditions such as a range of reaction temperatures, /CO molar feed ratios and a range of total pressures. Characterization of both precursors and calcined catalysts is carried out by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), BET specific surface area and thermal analysis methods such as TGA and DSC.

scholarly journals Meso-Structure Controlled Synthesis of Sodium Iron-Manganese Oxides Cathode for Low-Cost Na-Ion Batteries

2019 ◽  
Vol 166 (12) ◽  
pp. A2528-A2535 ◽  
Author(s):  
Hayley Hirsh ◽  
Marco Olguin ◽  
Hyeseung Chung ◽  
Yixuan Li ◽  
Shuang Bai ◽  
...  
Keyword(s):  
Manganese Oxides ◽  
Low Cost ◽  
Controlled Synthesis ◽  
Iron Manganese

Arsenite removal from groundwater by iron–manganese oxides filter media: Behavior and mechanism

2019 ◽  
Vol 91 (6) ◽  
pp. 536-545 ◽  
Author(s):  
Ya Cheng ◽  
Shasha Zhang ◽  
Tinglin Huang ◽  
Ye Li
Keyword(s):  
Manganese Oxides ◽  
Filter Media ◽  
Arsenite Removal ◽  
Iron Manganese

Relict joints in completely decomposed volcanics in Hong Kong

1982 ◽  
Vol 19 (2) ◽  
pp. 117-123 ◽  
Author(s):  
Y. C. Koo
Keyword(s):  
Hong Kong ◽  
Manganese Oxides ◽  
Strength Testing ◽  
Residual Soil ◽  
High Concentration ◽  
Strength Parameters ◽  
Decomposition Products ◽  
Joint Surfaces ◽  
Iron Manganese ◽  
Iron And Manganese

In a major cutting in the completely decomposed volcanics in Hong Kong, closely spaced relict joints were found throughout the residual soil. The persistence of the exposed joint surfaces varies from several centimetres to more than 10 m. The joint surfaces, which are generally smooth and sometimes slickensided, are usually coated with a thin black-brown deposit. The origin of this deposit is believed to be the precipitation of iron-manganese decomposition products that have filled the joints in the parent rock during the course of weathering. Chemical analyses carried out on typical specimens have confirmed a high concentration of iron and manganese oxides. Results of laboratory shear strength testing show that the peak strength parameters along joint surfaces and of the intact material are: c′ = 0, [Formula: see text] and c′ = 6 kPa, [Formula: see text] respectively. Analyses of joint survey data indicate that relict joint orientations occur in systematic major sets and that joint spacings roughly follow a Poisson distribution.

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