Cryptomelane(KxMn8−xO16): Natural active octahedral molecular sieve(OMS-2)

Lu, Anhuai; Gao, Xiang; Qin, Shan; Wang, Changqiu

doi:10.1007/bf03325676

Cited by 3 publications

(6 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The contents of K 2 O in XG-C-1 are 3.23-4.03 wt% which are close to reported 3.05-3.35 wt% in the natural cryptomelane from Xiangtan manganese deposit in China (Lu et al, 2003 Table 2). The results show silver is remarkably concentrated in cryptomelane.…”

Section: Chemical Compositionssupporting

confidence: 81%

See 1 more Smart Citation

The mineralogical characterization of argentian cryptomelane from Xiangguang Mn–Ag deposit, North China

Fan

Wang

Xing-tao

et al. 2015

Journal of Mineralogical and Petrological Sciences

View full text Add to dashboard Cite

Argentian cryptomelane as a quite rare variety is determined during the investigation of Mn-Ag ore samples from Xiangguang deposit along the northern margin of North China craton. The mineral observed by a polarizing petrographic microscope involves concentric ring-band, pisolitic and veinlet structures and greyish white color. The scanning electron microscopy reveals a large number of elongated nanocrystals in the forms of nanofibers and nanorods in this densely natural argentian cryptomelane. The specifically chemical features in two samples of XG-C-1 and XG-C-2 of cryptomelane are: (1) The silver content ranges from about 0.22-3.15 wt%, which is much higher than that of other manganese oxides including ranciéite, chalcophanite and coronodite found in this deposit as well. Both of two argentian cryptomelane samples feature two main Raman scattering contributions at about 580 cm −1 and 630 cm −1 , belonging to the Mn-O lattice vibrations within the MnO 6 octahedral double chains, which can distinguish from other three manganese oxides. The Ag + prefers to locate in the tunnel sites substituting K + of cryptomelane due to its large radius and the same monovalent state with K + . Some chain-width disorders characterized by transmission electron microscopy are probably caused by these cation substitutions.

show abstract

Section: Chemical Compositionssupporting

confidence: 81%

“…It is a typical 2 × 2 tunnel structure manganese oxide, which is composed of edge-sharing double [MnO 6 ] octahedral chains (Post et al, 1982;Lu et al, 2003). in the framework can be balanced by the insertion of large monovalent cation-K within the tunnel (Pasero, 2005).…”

Section: Discussionmentioning

confidence: 99%

The mineralogical characterization of argentian cryptomelane from Xiangguang Mn–Ag deposit, North China

Fan

Wang

Xing-tao

et al. 2015

Journal of Mineralogical and Petrological Sciences

View full text Add to dashboard Cite

show abstract

“…Pyrolusite is a stable MnO 2 phase in the supergene environment. When the potassium concentration in the formation environment is high, cryptomelane will replace pyrolusite [10,24,26]. The oolitic and pisolitic Mn oxide ore is pure cryptomelane, indicating a high degree of oxidation and a relatively high K mass fraction.…”

Section: Mn Oxide Phases Chemical Composition and Genesismentioning

confidence: 99%

“…Under different conditions, they can show different degrees of adsorption of heavy metal ions and adsorption and oxidation of anions including NO 3 − , PO 4 3− , F − , and S 2− . Manganese oxide can adsorb, transform, and degrade organic pollutants including phenol, ethane, ethylene, and synthetic organic acids, and it can decompose and transform CO 2 , NO x , and SO 2 [10,11]. All in all, Mn oxides show great potential for the transition to a green economy and mitigating environmental pollution.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

View full text Add to dashboard Cite

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.

show abstract

“…Dessa forma, naturalmente, colóides minerais contêm mais íons potássio ligados. Segundo Breznak e Brune (1994), Brune et al (1995) e Brune e Kuhl (1996), o elevado pH do estômago dos cupins também pode esclarecer o elevado teor de potássio trocável nos termiteiros, já que alcalinidade altera a configuração de alguns compostos minerais (LU et al, 2003;RIVES et al, 2004), que em solos argilosos possuem consideráveis quantidades de potássio adsorvidos nas argilas ou como minerais secundários.…”

Section: -130 Punclassified

Alterações Físicas E Químicas Do Solo Em Virtude De Construções Termíticas No Norte De Tocantins

Oliveira¹,

Santos²,

Neto³

et al. 2012

Reveng

View full text Add to dashboard Cite

A ação dos térmitas na pastagem promove mudanças químicas e físicas que auxiliam no incremento qualitativo no solo, como aeração, aumento do teor de argila na superfície do solo e de nutrientes elaborados. Nesse sentido objetivou-se verificar as alterações ocorridas em solos sob pastagem e em termiteiros em função da atuação dos térmitas no norte do Tocantins. O diagnóstico foi realizado em Neossolo Quartzarênico órtico e Latossolo Vermelho distrófico comparando os teores de argila, silte, areia, pH, matéria orgânica, fósforo, potássio, cálcio, magnésio e alumínio do solo adjacente aos termiteiros e as partes fracionadas dos mesmos (topo, meio e base). Não foram encontradas diferenças nos valores de P, MO, areia e silte entre as duas classes de solos. No entanto, quando se comparou topos entre centros, bases e área adjacente, os resultados foram distintos. Os cupins são componentes essenciais dos solos por serem de grande importância na ciclagem de nutrientes e atuarem de forma direta na pedogênese do solo, melhorando os teores de argila e silte antes percolados, além de influenciar na translocação e disponibilidade de alguns macronutrientes primários e secundários essenciais as plantas, e aumentar a porosidade, aeração, infiltração de água de solos.

show abstract

Cryptomelane(KxMn8−xO16): Natural active octahedral molecular sieve(OMS-2)

Cited by 3 publications

References 16 publications

The mineralogical characterization of argentian cryptomelane from Xiangguang Mn–Ag deposit, North China

The mineralogical characterization of argentian cryptomelane from Xiangguang Mn–Ag deposit, North China

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

Alterações Físicas E Químicas Do Solo Em Virtude De Construções Termíticas No Norte De Tocantins

Contact Info

Product

Resources

About