Properties of silica in water

Okamoto, Gô; Okura, Toshinori; Goto, Katsumi

doi:10.1016/0016-7037(57)90023-6

Cited by 160 publications

(55 citation statements)

References 13 publications

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“…Okamoto et al (1957) and Willey (1975b) found that the presence of colloidal alumina inhibited dissolution of amorphous silica and quartz. Rinsing diatom tests with solutions containing dissolved alumina decreased the solubilities of the tests (Hurd 1973).…”

Section: Nriagumentioning

confidence: 99%

Dissolved silica in pore waters of Lakes Ontario, Erie, and Superior sediments

Nriagu¹

1978

Limnology & Oceanography

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The distribution of dissolved silica in pore waters from Lakes Ontario, Erie, and Superior sediments is not directly related to the deposition of diatomites from the overlying water. It is proposed that silica concentrations in the pore waters are controlled by dissolution of fcrroaluminum silicate, AI,,Fe,,"+(SiO,),(OH)~~,-~~. The cryptocrystalline complex is formed in the sediments by the reaction of biogenic silica with aluminum and ferric oxyhydroxides or by the hydrolysis of clay minerals. A massive episodic flux of biogenic silica to the sediments follows the crash of diatom blooms. Most of the biogenic silica is however dissolved in the water column or at the sediment-water interface; a small fraction is fixed permanently in the sediments as the cryptocrystalline complex. Budget calculations show that regeneration of silica from Ontario and Erie sediments far exceeds annual input from external sources.

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Section: Nriagumentioning

confidence: 99%

Dissolved silica in pore waters of Lakes Ontario, Erie, and Superior sediments

Nriagu¹

1978

Limnology & Oceanography

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“…The siliceous deposits are by no means chemically pure hydrous silica and contain various elements, especially alumi nium and/or iron (Ito et al, 1977;Rothbaum et al, 1979;Ichikuni et al, 1983 andKristmann sdottir, 1989), suggesting that effects of the elements on the deposition of silicic acid from geothermal water should be considered. Trace amounts of aluminium and iron greatly decrease the solubility of amorphous silica (Iler, 1973), thereby precipitating large amounts of silicic acid from aqueous solution (Okamoto et al, 1957). Both iron (III) hydroxide and aluminium hydroxide can absorb large amounts of silicic acid from aqueous solutions, and the silicic acid polymerizes to form silica (Yokoyama et al, 1980(Yokoyama et al, , 1982(Yokoyama et al, and 1984.…”

Section: Introductionmentioning

confidence: 99%

Siliceous deposits formed from geothermal water.I. The major constituents and the existing states of iron and aluminium.

et al. 1993

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JapanIn the deposition of siliceous material from geothermal water, a relationship between chemical com positions of geothermal waters and siliceous deposits was investigated. The results indicated that iron and aluminium were concentrated into these siliceous deposits. For the chemical state of the iron in the deposits, some oxides and oxyhydroxides, sulfide and amorphous iron silicate were identified by powder X-ray diffraction and "Fe Mossbauer spectroscopy. For the aluminium, two states were detected by 27A1 MAS NMR: 6-coordinate aluminium (such as aluminium hydroxide) and 4-coordinate aluminium substituting a Si atom site in the deposit. In some deposit samples, both 4 and 6-coordinate aluminium were detected, but in others only the former was found.

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“…Vacuolar facies are formed by the destruction of the gulb (glebular) bridges contained in the massive facies. The nodular facies with a high silica and kaolinite contents might be the resilicification of bauxite during the leaching process following by the equation proposed by Bitom (1988): 2Al (OH) 3 + 2SiO 2 Al 2 Si 2 (OH) 4 O 5 +H 2 O or the solubility of the silica is generally controlled by alumina which the both combines to form alumino silicates such as kaolinite, Okamoto et al, (1957). According to Annan and Butt (2010), the pseudobréccia facies is the richest in gibbsite and low contents of iron and silicate and might be qualify as good bauxite quality in Cameroon.…”

Section: Mineralogy and Geochemistry Of Bauxite In Bangam Localitymentioning

confidence: 99%

Mineralogical, Geochemical and Distribution Study of Bauxites in the Locality of Bangam and Environs (West Cameroon)

Sojien¹,

Mamdem²,

Wouatong³

et al. 2018

ESR

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The bauxite duricrust in the Bangam and surroundings is classified into three major storey levels as follows: the upper level on top of the plateaus where the continuous bauxites outcrop in slabs over distances of about 1 km, the intermediate level on top and at the flanks of the hills where the bauxites flush in metric blocks, the lower level at the talwegs where bauxites duricrust are gravels. The average thickness of the duricrust is 9.6m and extends over an area of about 9.5km 2 . Five types of facies are encountered here: nodular, pisolitic, pseudobreccia, vacuolar and massive. These different facies were carried out by X-ray fluorescence spectrometry, X-ray diffractometric, thermal analysis (ATD / ATG) and by polarizing microscope observation. The results of these analyses show that, gibbsite is the dominant mineral; kaolinite, anatase, hematite, goethite, magnetite and ilmenite are also present. The chemical composition of the major elements that characterize bauxites are 38-60% Al 2 O 3 ; 2 -22% SiO 2 and 9-42% Fe 2 O 3 . These values are almost similar to those obtained in Doumbouo-Fokoué, Ghana, Ngaoundal, and Minim-Martap precisely at Briskok prospect. The different minerals paragenesis and geochemistry data show that, the Bangam locality is a bauxite ore deposit in spite of a high content of iron and silicate of some facies, nevertheless, these can be used in some industries.

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Properties of silica in water

Cited by 160 publications

References 13 publications

Dissolved silica in pore waters of Lakes Ontario, Erie, and Superior sediments

Dissolved silica in pore waters of Lakes Ontario, Erie, and Superior sediments

Siliceous deposits formed from geothermal water.I. The major constituents and the existing states of iron and aluminium.

Mineralogical, Geochemical and Distribution Study of Bauxites in the Locality of Bangam and Environs (West Cameroon)

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