Mn Hydroxides Research Articles

Trace elements in volcanogenic manganese oxides and iron oxides; the San Francisco manganese deposit, Jalisco, Mexico

The San Francisco manganese deposit, located in western central Mexico in a Tertiary, continental-volcanic province, is composed of Mn oxides and Fe oxides. The small geographic extent of the tuffs which enclose the oxides, and their sorting, rounding of constituents, and distinct stratification, point to deposition in a small lacustrine basin. The stratigraphic conformity of the oxides with the tuffs and their purity and zoning pattern suggest precipitation as a chemical sediment from volcanic solutions, at a time of decreased volcaniclastic contributions. As the mineralizing solutions entered the depositional basin, the two oxides precipitated separately, Fe oxides closer to the source and Mn oxides farther from it, in response to a gradual increase in pH and Eh of the solutions through mixing with alkaline, oxygenated waters in the depositional basin.Spectrographic analyses for minor and trace elements reveal that both the Mn oxides and the Fe oxides in the San Francisco deposit are strongly enriched in As, Ba, Cu, Mo, Pb, Sr, and V compared to crustal averages. Except for V, the concentrations of these elements are higher in the Mn oxides than in the Fe oxides by factors ranging from 3 to 140. Thus, the Mn oxides reflect the composition of the mineralizing solutions much more strongly than the Fe oxides. Mineralogy and solubility calculations suggest that the minor elements were removed from solution by adsorption rather than by precipitation in response to saturation. Since both oxides when freshly precipitated adsorb minor elements strongly, the distinct partition is interpreted as a result of diagenetic recrystallization processes. During recrystallization, Ba, Sr, and Pb adsorbed on precipitating hydrous Mn oxides form manganates of the cryptomelane-hollandite group, and Cu can substitute for Mn in the lattice of mixed valence Mn oxides. These elements would be desorbed from recrystallizing Fe oxides because of their inability to form minerals with trivalent Fe or to substitute for Fe in the lattice of its oxides. Depending on the geochemical characteristics of the depositional basin, they would form sulfates or carbonates in situ, be built into spatially associated Mn oxides, or reprecipitate in genetically related sulfidic sediments. The less distinctly partitioned minor elements As, Mo, and V can be accommodated in both Mn and Fe oxides, by formation of arsenates, molybdates, and vanadates or by substitution for either Mn or Fe in their oxides.High concentrations of the minor elements which characterize the San Francisco deposit have been reported from other Mn and Fe oxide deposits of volcanic association. The presence or unusual concentration of these elements in Mn and Fe oxides, or in genetically related sulfates, carbonates, or sulfides, is supporting evidence for volcanic contributions to their formation.

Adsorption of Cu, Zn and Pb near sulfide deposits by hydrous manganese—Iron oxide coatings on stream alluvium

Hydrous oxides of Mn and Fe scavenge several base metals in the surficial environment by adsorption and coprecipitation. Results of laboratory investigations suggest increased adsorption compared to coprecipitation where higher concentrations of metal ions exist in solution, such as generally occur near an oxidizing mineral deposit. Stream cobbles with hydrous oxide coatings, collected from the Valley and Ridge Province in northwestern Virginia, were immersed in prepared aqueous solutions of CuZnPb for 50 hr. Substantial quantities of each metal were absorbed from solution. Considerably greater proportions of the newly adsorbed metal could be extracted by ammonium citrate than background concentrations of metal initially present in the coatings. Analysis of hydrous oxide coatings collected at varying distances upstream and downstream from a small CuZnPb-sulfide deposit produced similar results. Following the same analytical procedure, considerably greater proportions of the total Cu and Zn were extracted by ammonium citrate from samples near the mine than from those upstream or at a greater distance downstream. If adsorption of metal by hydrous oxides is generally more important compared to coprecipitation where higher concentrations of metal ions are available in solution, the relation might be of practical value. The sulfide deposit is clearly delineated if Cu and Zn extracted by ammonium citrate is expressed as a percent of total Cu or Zn. Previous studies have shown that similar deposits are not clearly delineated by analysis of hydrous oxides unless ratios of metal to Mn or Fe are calculated.

The Nature of Selected Prairie Lake and Stream Sediments

AbstractThe mineralogy and related chemistry of selected lake and stream sediments from the upper Qu'Appelle River basin in southern Saskatchewan, Canada, was examined. The principal crystalline clay minerals present in the colloidal fractions of the sediments are smectite, vermiculite, kaolinite, mica, quartz, and feldspar. The cation‐exchange capacity of the sediments varies from 16.3 to 28.8 meq/100 g, and the pH ranges from slightly acid to mildly alkaline. The hydrous oxides of Al, Fe, Mn, and Si are present in significant quantities in both the colloidal and noncolloidal fractions of the sediments; this is significant because these oxides likely exert the dominant chemical control on the movement of many nutrients and pollutants in aquatic environments. Calcium and Mg carbonates comprise a significant fraction of the sediments. Most of the C in the sediments is in the organic form; the organic C content varies from 1.2 to 6.0%. Because crystalline clay minerals, poorly ordered sesquioxides, and organic matter play a vital role in the retention and cycling of nutrients and pollutants in aquatic environments, a knowledge of the nature and properties of sediments is fundamental to efforts to preserve and improve the quality of natural water systems.

Zinc, Cadmium and Manganese Uptake by Soybean from Two Zinc‐ and Cadmium‐Amended Coastal Plain Soils

AbstractTwo Coastal Plain soils were used to evaluate the effects of organic matter and Fe and Mn hydrous oxides on Zn phytotoxicity, and on Zn, Cd, and Mn uptake by soybean seedlings. Fertilized Pocomoke sl and Sassafras sl were limed to pH 5.5 and 6.3 with CaCO3 when adding Zn (six levels between 1.3 and 196 mg/kg at pH 5.5; seven levels between 1.3 and 524 mg/kg at pH 6.3). Cadmium was added at 1% of the added Zn. ‘Beeson’ soybean (Glycine max L. Merr.) was grown 4 weeks, and the trifoliolate leaves evaluated for dry weight yield and for their Zn, Cd, and Mn concentrations.The higher organic matter Pocomoke soil was more effective than the Sassafras soil in reducing metal uptake and Zn phytotoxicity. Foliar Zn levels associated with yield reduction of soybean grown on Pocomoke differed with soil pH. Cadmium uptake was significantly lower on the Pocomoke soil. Foliar Mn increased to reported phytotoxic levels (>500 mg/kg) with increased added Zn only on the Sassafras soil at pH 6.3.DTPA‐extractable Zn and Cd were linear functions of added Zn and Cd for both soils; 0.01M CaCl2‐extractable Zn and Cd were curvilinear (increasing slope) functions for the Sassafras and linear for the Pocomoke soil.Thus, soil type can strongly influence Zn, Cd, and Mn uptake, as well as Zn phytotoxicity to soybean. Soil organic matter appears to be more important than hydrous oxides of Fe and Mn in moderating the effects of excessive soil Zn and limiting Zn and Cd uptake. Induced metal toxicities (Mn) may depend on many factors, and should be considered an integral part of any characterization of specific metal phytotoxicities (e.g. Zn).

Soil modification to minimize movement of pollutants from solid waste operations

Before confident guidelines for disposal of potentially hazardous waste constituents can be established, a knowledge of a multitude of factors influencing metal migration rates in soils is necessary. Research identifying the principal soil factors has been published, and the movement of trace metals in soils is described as a statistical function of specific properties of the soil medium. The necessity of characterizing the three main site‐disposal environments as to (a) soil, (b) leaching solution, and (c) specific polluting constituent also has been established and is discussed. Prominent soil parameters influencing attenuation components are (a) clay content, (b) silt content, (c) presence of lime, (d) pH level, and (e) hydrous oxides of Fe, Mn, and Al. With these and other known parameters, certain soil modifications and low‐cost liners for disposal sites are suggested. All sites require modification if migration of pollutants is to be retarded and prevented from reaching underground water sources or ...

FeMn crusts from the southern Tyrrhenian Sea

Dark crusts and concretions on volcanic and calcareous rocks dredged from seamounts west of the Aeolian Islands, southern Tyrrhenian Sea, consists mainly of amorphous FeMn hydroxides, with some goethite, todorokite, birnessite and clastic minerals. Chemically they consist of predominant Fe (up to 45%) and Mn (up to 12%), with significant amounts of Zn, Ni, Co and Cu. That the REE distribution patterns are similar to those of shallow Pacific derivation — from hydrothermal waters cognate or cycled through volcanic rocks of intermediate composition — is tentatively suggested.

MASSIVE IRON FORMATIONS IN SOME GLEYSOLIC SOILS OF SOUTHWESTERN ONTARIO

Massive, but very localized, iron formations have been noted in some Humic Gleysols in southern Ontario. Some of these formations weigh up to 9 kg, and invariably occur at the contact zone between sandy loam to loam surface horizons and underlying clay-rich subsoils. The contents of Fe2O3 and MnO2 of 16 samples varied from 19.6 to 49.9% and 0.8 to 11.1%, respectively, although no crystalline oxides or hydroxides of Fe or Mn could be detected by X-ray diffraction. The localized occurence of these formations suggests that Fe2+ and Mn2+ are moving laterally through the subsoil and oxidizing at some seepage point downslope in the more aerated surface horizons.

Secondary controls on mercury in soils of geothermal areas

Abstract A study of the Hg distribution in soils of the Long Valley, California, geothermal area and several minor geothermal districts in Colorado was made. A1-horizon soil samples were collected on a grid system in the Colorado areas and on a grid system from selected areas of the Long Valley caldera. The primary objectives of this study were to determine the applicability of anomalously high Hg concentrations in soils to exploration for geothermal systems and to evaluate the importance of secondary controls such as organic matter, Fe and Mn hydrous oxides on Hg concentration in soils overlying geothermal systems. Statistical analysis identified two populations of Hg in soils, one related to geothermal activity and the other unrelated. Stepwise regression was used to evaluate the relative importance of secondary controls on Hg. Organic carbon was found to be the most important influence in the California geothermal data, whereas Mn was most important in the Colorado data. Generally, the secondary controls of Hg are subtle and are overwhelmed in an area of prominent geothermal activity. Some secondary variables have a significant influence on Hg in soils and can be useful in redefining areas of anomalous Hg leakage. The technique is likely to be of most use in evaluating potential geothermal areas with weak surface expression.

Anorganisch‐katalytische Umsetzungen von Cyanamid und dessen Metaboliten in Quarzsand II. Cyanamidabbau unter dem Einfluß von Metalloxiden und Temperatur

Inorganic catalytical breakdown of cyanamide and its metabolites in quartz sand II. Cyanamide breakdown as influenced by metal oxides and temperatureThe inorganically catalysed breakdown of cyanamide with addition of water in presence of metal oxides was studied in quartz sand. Cyanamide breakdown and the formation of metabolites was investigated in relation to the kind and quantity of metal oxides as well as temperature. The oxides or hydroxides of Mn, Cu, Zu, Ni, Co influenced the rate of cyanamide breakdown very differently. Decreasing the quantity of oxides (amorphous Fe(III) – hydroxide, ochre, rust) from 0.5 to 0.1 g or 0.05g/100g of quartz sand retarded cyanamide breakdown in an oxide specific formation of urea and dicyanamide. The influence of temperature (5 and 18°C) on the breakdown was not so great as that of moisture (5% and 150% of the water capacity). A low temperature (5°C) and high moisture regime (150% of the water capacity) retarded cyanamide breakdown considerably almost completely stopping it. The type and concentration of the metal oxide (iron oxide) as well as the moisture and temperature of the reaction medium are very important in the inorganically catalysed cyanamide and water reaction leading to the formation of urea or dicyanamide.

Effect of dissolved oxygen on chemical transformations of heavy metals, phosphorus, and nitrogen in an estuarine sediment

The effect of dissolved O 2 on the chemical transformations of Fe, Mn, Zn, Cu, Pb, Cd, NH 4 + -N and P in an estuarine sediment suspension was investigated under laboratory conditions. Reduced sediment suspensions were constantly purged with a gas mixture containing 0.11%, 2.1% and 21% O 2 at a flow rate of 20 ml min −1. Suspension samples were taken at various time intervals and extracted for different chemical fractions. The data indicate that increasing O 2 concentrations in the gas mixture resulted in lower sediment pH and higher oxidation-reduction potential (redox potential) with time. Changes in redox potential and pH strongly modified the distribution of trace metals in various chemical fractions. The hydroxylamine hydrochloride extraction failed to selectively remove oxides and hydroxides of Mn without dissolving a substantial proportion of reactive Fe, as the recovery of Fe by this extractant was 8 to 10 orders of magnitude greater than Mn. The large recovery of Fe with Mn in this fraction makes it difficult to distinguish trace metals associated with Mn oxides from those associated with Fe oxides. A substantial fraction of total sediment Zn was associated with potentially bioavailable chemical forms, which may be mobilized to more readily available forms due to changes in the physicochemical properties of the sediment-water system. Significant correlation coefficients obtained between soluble Pb, Cd and Cu and different Fe fractions suggest a strong relationship between these trace metals and Fe compounds. Phosphorus and NH 4 + -N concentrations decreased sharply with time as a result of increased redox potential levels in the 2.1% and 21% O 2 levels. The effect of the 0.11% O 2 treatment was negligible. This indicates that oxidized sediment conditions may be an important factor in regulating eutrophication by reducing the levels of P and N available for biota. This necessitates a careful study of changes in the dissolved O 2 concentration (reflected by redox potential levels) in the sediment-water system.

The use of 210Pb as a heavy metal tracer in the Susquehanna River system

Analysis of soil profiles and shallow ground water in the Susquehanna River basin, northeastern U.S.A., indicates that the atmospheric flux of 210Pb is efficiently scavenged by the organic-rich horizons of the soils. This atmospherically supplied 210Pb in soil profiles can only be lost from the system by soil erosion. Based on the annual sediment yield of the Susquehanna River and the excess 210Pb concentration in particulate matter, a mean residence time of 2000 yr is calculated for metals similar to Pb in soil profiles. The West Branch of the Susquehanna River (WBSR) is strongly affected by acid mine drainage and is low in pH and high in dissolved ( <0.4 μm) 210Pb, Fe and Mn. Along its course iron hydroxide is precipitating at a pH of between 4 and 4.5 and the 210Pb supplied by the acid mine water is diminished by about 25% as a result of dilution. As the WBSR enters the Valley and Ridge Province of the Appalachians it has a 210Pb concentration of ~ 0.2 dpm/l. At this juncture it receives a considerable influx of alkalinity from tributaries draining carbonate terranes, resulting in neutralization of the sulfuric acid and increase of the river pH to around 6.5–7. This pH adjustment is accompanied by the precipitation of Fe and Mn. Due to the slow rate of Mn removal from solution, the Mn precipitation extends a considerable distance down river from the point of acid neutralization. Analyses for 210Pb in the river at points in or below the region of Mn precipitation show that 210Pb is rapidly scavenged from solution onto suspended particles. From the data it is possible to calculate the removal rate of Pb from water in the presence of Fe and Mn hydroxides and other particles. At a pH of 4–4.5 Pb removal is nonexistent relative to the river flow rate, but at a pH of 6.5–7 the 210Pb data indicate a residence time of <0.7 day for dissolved Pb.

Experiments on the uptake of zinc and cadmium by manganese oxides

Experiments on the uptake of Zn and Cd by synthetic hydrous Mn oxides were carried out in an ionic medium at pH 3.5 and at pH 4. A slight preference for uptake of Cd2+ over Zn2+ was observed with both birnessite and nsutite, the Cd/Zn ratio being different for each mineral. Subsequently, the desorption of Zn and Cd from the obtained products in artificial seawater was studied. In this medium Cd is desorbed from the Mn oxides to a much higher extent than is Zn. The latter observations can be satisfactorily explained by the large difference of complex formation for the two metals in seawater, slightly counteracted by the preferential uptake of Cd2+ over Zn2+. The order of magnitude of the Zn/Cd ratio in natural manganese nodules is compatible with the ratio calculated on the basis of experimental results, taking fair estimates of the actual inorganic Zn/Cd ratio in seawater and of the pH of deep ocean water.

Some geochemical controls on Ni and Co concentrations in marine ferromanganese deposits

The uptake of Ni and Co in the hydrous Mn oxide or the amorphous Fe-oxide phases of ferromanganese deposits in the oceans was studied by electron-microprobe analyses of 17 natural manganese nodules and by experiments on desorption-dissolution of these metals from synthetic Fe oxide or Mn oxides and natural nodule material. Ni was found to occur nearly always in the Mn-oxide phases of natural nodules, while Co occurs both in the Mn-oxide and Fe-oxide phases, with a slight preference for the latter. The solubility of Ni and Co (from coprecipitates of these metals with Fe hydroxides after aging) in seawater was found to depend strongly on the crystallinity of the host phase. The adsorption of Co by the synthetic Mn oxides from seawater was higher than that of Ni. The experimentally determined solubility of Ni and Co in seawater from natural nodule material is extremely low and matches the concentration range of these metals in ocean water.

Lateral translocation of soil plasma through a small valley basin in the Northaw Great Wood, Hertfordshire

AbstractThe paper looks at the process of lateral translocation in a small valley basin from the Northaw Great Wood, Hertfordshire. The valley basin comprises four lithostratigraphic units (London Clay and Pebble Gravel, and the others a mixture of these two), which were initially established in the field by a rough assessment of texture. Particle size analysis validated the lithostratigraphic units as delineated in the field; it was found unnecessary to alter the boundaries of the units. Patterns of lateral translocation of silt and clay (measured by the hydrometer method) and the amorphous colloidal hydrous oxides and hydroxides of Al, Fe, Mn and Si (measured in oxalate solution by atomic absorption spectrophotometry) are inferred from balance sheets of the relative gains and losses of the materials. Materials from horizons formed in lithostratigraphic units derived from London Clay are balanced against a clay dilution factor; those from the lithostratigraphic unit of Pebble Gravel against the dilution of sand on a clay‐free basis. The results lead to the following conclusions about the process of lateral translocation: it has been a significant contributor to soil development; larger amounts of material have moved down‐slope towards the hollow than over the nose because there has, theoretically, been more throughflow in the hollow; for some materials there has been less down‐slope transport in lower horizons owing to less throughflow in them.

Factors Controlling Chemical Composition of Formation Waters, Alberta: ABSTRACT

Twenty major and minor components were determined in 79 formation waters from oil fields and gas fields in Alberta. An R-mode statistical factor analysis revealed that the major influence on composition has been from the original seawater, with additional effects due to the uptake of Br and I from organic matter and the decomposition of sulfides or H2S. Other possible processes which may have been operative include differential solution of evaporites, exchange of alkali metals on clay surfaces, and the removal of hydroxides of Fe, Mn, Ni, and Co from the surrounding sedimentary rocks. End_of_Article - Last_Page 852------------

The alizarin-S spot test for aluminium in the presence of zirconium, in systematic qualitative analysis

In qualitative systematic analysis Zr, giving the same color by spot test with alizarin-S as Al does, is to be eliminated from the ammonium hydroxide-group. A procedure is described for extraction of Zr from the precipitated hydroxides of Al, Cr, Fe, Mn, and Ti.

Solvent effect of hydroxylamine hydrochloride in the citrate-soluble heavy metals test

Results obtained with and without the reagent may be radically different, particularly where samples contain significant amounts of hydrous Mn oxides.

Untersuchungen zur Geochemie des Bleis

After discussing literature on the geochemical distribution of lead, a quantitative spectrochemical method is described (0.01% Bi standard). The sensitivity of 0.0001% Pb is attained by relative concentration of light volatile elements with a double-arc instrument. In this investigation more than 500 analyses for lead of representative samples are discussed (more than 250 own determinations). During the last 3.3 . 10 9 years the total amount of lead of the earth's crust has increased only by 20% from radiogenic sources. The average lead content of micas and potassium feldspars (~0.0025%) surpasses that of the lithosphere (0.0015%). Remarkable amounts of 0.010% Pb are gathered in the feldspars of pegmatites. Olivine and quartz (excepting rose-quartz) have the lowest contents (~0.0001% Pb); those are expected after their structural properties. Lead replaces potassium in its structural positions owing to similar ionic dimensions. In the course of magmatic differentiation the proportions K/Pb and Ba/Pb are increasing, only excepting some late minerals. Adulars, feldspathoids and zeolites are favoured in the replacement of K, Na and Ca. The feldspars contain the main lead content of eruptive rocks. The following figures are average Pb abundances of a great number of samples: granite 0.0019%, granodiorite 0.0015%, diorite 0.0010%, basalt 0.0006%, ultrabasic rocks 0.0003%. Galena seems to be a very rare compound in normal rocks. The behaviour of lead in rock alteration (weathering, mobilization, concentration, etc.) is discussed. Factors for concentration are low solubility (PbS, Bleiphosphat adsorption (clay minerals, Mn hydroxides, ferric hydroxides) and action of organisms (foraminiferae, plants, etc.). The clay minerals contain the bulk of lead in sediments. The relative high contents of Pb, Zn and Cu of pelagic sediments cannot have been derived entirely from continental weathering. It must be assumed that a part is due to volcanic exhalations. The following averages are results of sediment analyses: nonpelagic argillaceous rocks 0.0020%, deep-sea clays (Atlantic Ocean) 0.0043%, deep-sea clays (Pacific Ocean) 0.014%, sandstones 0.0007%, limestones and dolomites 0.0009% Pb. Part of the lead content of metamorphic rocks can be derived from their parent material. It increases from greenschists, amphibolites, granulites (0.0010%), to mica-schists and gneisses (0.0023% Pb). A number of lead analyses from specific minerals of metamorphic rocks are reviewed. Natural environments very rarely permit the formation of Pb ⃜ . The Goldschmidt rules on the relationships between distribution of an element and its ionic dimensions and ionic charge give a sufficient explanation of most geochemical characteristics of lead.