H. Kodama

Mineralogy of rhizospheric and non-rhizospheric soils in corn fields

Technical limitations have restricted investigations of rhizosphere mineralogy. Various analytical techniques were applied to assess root-mineral associations and dynamics in natural soils under corn production. Soil samples were collected between four and five weeks after planting and included rhizospheric and non-rhizospheric soils, and undisturbed block samples containing corn root systems. Analytical techniques were applied and included; X-ray diffraction, optical microscope, SEM, EDXRA with SEM, transmission electron microscope (TEM), electron energy loss spectra with TEM, high-resolution transmission electron microscope (HRTEM) and microanalysis with HRTEM. The mineralogy of the rhizosphere differed from that of the bulk soil. Within the rhizosphere, minute platy particles which were mostly vermiculitic minerals, were particularly concentrated near or on root surfaces. These platy mineral particles were not attached to the entire area, but only to certain areas of root surfaces. Therefore, we report quantitative evidence for mineralogical changes in the rhizosphere in soil environments.

Reactions of Polynuclear Hydroxyaluminum Cations with Montmorillonite and the Formation of a 28-Å Pillared Complex: Reply

Polynuclear hydroxy-Al cations were prepared by partially neutralizing dilute solutions of aluminum chloride. These cations were introduced in the interlayer space of montmorillonite by cation exchange, which formed heat-stable pillars between the silicate layers. Polynuclear hydroxy-Al was preferentially adsorbed on montmorillonite compared with monomer-Al; the maximum amount adsorbed was ∼400 meq/100 g of montmorillonite. Of this amount 320 meq was non-exchangeable. The 001 X-ray powder diffraction reflection of the polynuclear hydroxy-Al-montmorillonite complex was at 27 Å, with four additional higher-order basal reflections, giving an average d(001) value of 28.4 Å. This complex was thermally stable to 700°C. An analysis of the basal reflections by the Fourier transform method indicated that the 28-Å complex had a relatively regular interstratified structure of 9.6- and 18.9-Å component layers with a mixing ratio of 0.46:0.54. This ratio implies that the hydroxy-Al pillars occupied every second layer. Considering the relatively small amount of Al adsorbed and the thermally stable nature of the structure, the hydroxy-Al pillars must have been sparsely but homogeneously distributed in the interlayer space.

CHARACTERIZATION OF COLLOIDAL SOLIDS FROM ATHABASCA FINE TAILS l

During processing of Athabasca oil sands, the finely divided solids form an aqueous suspension, which ultimately stabilizes as a gel-like structure retaining up to 90% of the process water. This gelling phenomenon is believed to be caused by colloidal inorganic components. Kaolinite and mica are the main crystalline minerals in these colloidal solids; swelling clays are present in only trace amounts. Non-crystalline components are more concentrated in the finer fraction of the solids. Although the surfaces of the colloidal solids are virtually free of Fe, some contamination with polar organic matter is observed.

Quantification of crystalline and noncrystalline material in ground kaolinite by X-ray powder diffraction, infrared, solid-state nuclear magnetic resonance, and chemical-dissolution analyses

The capabilities of X-ray powder diffraction (XRD), infrared absorption (IR), solid-state magicangle-spinning nuclear magnetic resonance (MAS-NMR), and chemical dissolution methods were assessed for estimating the amount of noncrystalline material in a ground kaolinite. The Georgia kaolinite was ground in a mechanical mortar for various lengths of time to produce a set of ground samples containing different amounts of the resulting noncrystalline material. In the XRD method, the intensities of characteristic reflections at 7.2 and 4.47 Å did not respond proportionally to the amount of crystalline kaolinite. Although a transmission-type X-ray diffraction method using the hk reflection gave a slightly better estimate than the reflection-type X-ray diffraction method using the basal reflection, both methods gave overestimated values for the amount of noncrystalline material. This overestimation may have been caused by a masking effect due to coaggregation. Using the characteristic IR absorption band at 3700 cm-1 underestimated the amount of the noncrystalline material, if the proportion of this material <50%.Extraction with NaOH gave estimations 15 to 20% greater than extraction with alkaline Tiron, except for the sample ground for 24 hr, for which both extractions indicated the presence of about 50% noncrystalline material. X-ray powder diffraction data of the residues after these extractions indicated that they consisted of crystalline kaolinite. 29Si NMR spectra of samples ground for » 30 hr suggested that SiO4 tetrahedra were considerably distorted.27 Al NMR spectra showed a signal for tetrahedral A1 for the sample ground for 10 hr, which increased with an increase in grinding time. Plots of the Al(IV)/[Al(IV) + Al(VI)] ratios vs. time were similar to those of chemical extraction curves. Inasmuch as extraction with hot 0.5 M NaOH is a rather harsh treatment, the composition of the noncrystalline material must have been similar to that of the crystalline kaolinite. The chemical dissolution using alkaline Tiron appeared to be superior to other methods, such as XRD, IR, and NaOH extraction, for estimating the amount of noncrystalline material in kaolinite.

Non-crystalline inorganic matter-humic complexes in Athabasca oil sand and their relationship to bitumen recovery

Bitumen-free solids from different grades of Athabasca oil sand were fractionated according to particle size before and after treatment with sodium pyrophosphate (Na4P2O7) solution. All solids showed decreasing amounts of organic matter from coarse to fine fractions. The concentration of organic carbon retained in all size fractions after the treatment was found to be significantly lower as compared with that before the treatment. The mineralogy and some chemical properties of the material separated as a result of treatment were investigated. The data obtained indicate that treatment releases mostly non-crystalline compounds (possibly metal oxides in some kind of association with humic matter). A cold-water agitation test (CWAT) was used to correlate bitumen recovery with the amount of inorganic matter-humic complexes separated. It was observed that most of the bitumen was liberated when inorganic matter-humic complexes could be separated during the CWAT. For some oil sands complexes could not be isolated and in these cases most of the bitumen appeared to be associated with that fraction of solids consisting of globules of fine sand and clay particles cemented together with humic matter.

Effect of the presence of aluminum ions in iron solutions on the formation of iron oxyhydroxides (FeOOH) at room temperature under acidic environment

The hydrolytic behavior of Fe solutions at room temperature under acidic conditions was investigated. In the presence of Al ions, with Cl and NO3 as associated anions, the Fe hydrolysis began almost instantaneously and a crystalline β-FeOOH (akaganeite) was formed in the AlCl3/FeCl3 system within a short period. Initially the particles were small with large surface area. However, with time the particles grew in size and the surface area decreased. After about 42 days of equilibration, the akaganeite particles grew to 60–300 nm long, 10–50 nm wide and with a surface area of 55 m2/g, which is similar to other reports for akaganeite prepared at higher temperatures. In the NO3 system [Al(NO3)3/Fe(NO3)3], lepidocrocite (γ-FeOOH) and goethite (α-FeOOH) were formed. In a mixed anion system (Cl/NO3) solid phases identified were akaganeite (β-FeOOH) and lepidocrocite (γ,-FeOOH). The introduction of poly-nuclear hydroxy-Al along with monomer Al in Cl and NO3 systems of Fe affected the quantity and quality of the solid phase. The crystallinity of β-FeOOH formed in the presence of polynuclear hydroxy-Al ions in a Cl-system was more disordered than when it formed in the presence of monomer Al-ions alone. In NO3 systems, polynuclear hydroxy-Al hindered the formation of goethite (α-FeOOH). Our experiments showed that Fe oxyhydroxides crystallize readily under acidic conditions in the presence of Al ions and the data also indicated that the Cl was essential for the crystallization of akaganeite, whereas goethite was formed in those systems when Cl was absent.

Possible identification of poorly crystalline inorganic matter present in Athabasca oil sands

Abstract In Athabasca oil sands there is a fraction of poorly crystalline minerals tightly bound to humic matter. This fraction resists subsequent wetting by water and introduces serious problems in bitumen recovery when using water-based processes. In this study 29 Si solid state magic angle spinning (MAS) NMR, infrared spectroscopy and transmission electron microscopy were applied to characterize these minerals isolated from Athabasca oil sands of estuarine and marine origin. It was demonstrated that poorly crystalline inorganic matter present in Athabasca oil sands is comprised of aluminosilicates, most probably allophane-like minerals. Humic matter could interact with this type of material through incorporation of an organic anion as a ligand to a metal ion, coulombic and van der Waals forces and hydrogen bonding.

Mineralogy of heavy mineral concentrates from oil sands

Abstract The distribution of heavy minerals in concentrates, obtained from Alberta oil sand tailings using acid demineralization and oil phase agglomeration, was determined by X-ray diffractometry. The data have demonstrated the effectiveness of oil phase agglomeration techniques in rejecting gangue and other unwanted minerals such as pyrite during the concentration of heavy minerals. The results also suggest that titanium minerals could possibly be separated from zircon in the mineral concentrate by acid dissolution. Due to the different modes of agitation during collection, the mineralogical components of the two samples obtained from Suncor sludge differ considerably.

Polynuclear hydroxyaluminum-montmorillonite complexes: Formation of 18.8 Å and 28 Å pillared structures

Abstract Polynuclear hydroxyaluminum-montmorillonite complexe were prepared by treating Na-saturated montmorillonite with partially neutralized solutions of Al-containing monomer and polynuclear hydroxyaluminum species. The polynuclear hydroxyaluminum cations were preferably adsorbed by montmorillonite over monomer Al. The maximum quality of the polynuclear hydroxyaluminum adsorbed was ≈400 meq Al/100 g of montmorillonite and was independent of OH/Al molar ratios of hydroxyaluminum solutions. Three types of complexes were characterized by X-ray diffraction analysis; 18.8 A phase, 28 A phase and an intermediate phase. Initial conditions for drying suspensions containing complexes were found to be determining factors for the type of solid complex formed. Extremely dry conditions favored the formation of the 18.8 A phase, whereas ambient conditions produced the intermediate phase. On aging, these phases were gradually transformed to the 28 A phase. Upon heating at 700°C the 18.8 A phase was converted to the 28 A phase. The calculated average chemical composition of the polynuclear hydroxyaluminum cations adsorbed in montmorillonite layers was [Al(OH)0.56+2.44]n. The quantity of the maximum adsorption, ≈400 meq, was only a quarter of the quantity of the interlayer cations required to form a chlorite structure which has a layer thickness of 14.2 A. In spite of low amounts of hydroxy-Al adsorbed, the observed large basal spacings indicated that the complexes found in the present investigation must have pillared structures. From X-ray data, the height of the pillars was found to be ≈9.2 A. This and chemical data suggested that the Johanssons model molecule [Al13O4(OH)24(H2O)12]7+, was most suitabl e for the pillar. If this is the case, then one molecule occupied an area of 12–13 montmorillonite unit cells at every layer in the 18.8 A phase, whereas two cations occupied the corresponding area at every second layer in the 28 A phase. Therefore, a transformation from the 18.8 A phase to the 28 A phase could be explained by the migration of the cations from an interlayer space of the 18.8 A phase to one layer above or below.

Ca-RECTORITE FROM SANO MINE, NAGANO PREFECTURE, JAPAN

Rectorites containing various amounts of Ca were found at the Sano Mine, Nagano Prefecture, Japan. The Ca content in nonexchangeable form varied from 1.0 to 3.9% CaO. With more than 3.4%, they may be called Ca-rectorite. Chemical data of the most Ca-rich sample showed that Ca was the dominant interlayer cation, and gave a structural formula of (Mg0.16)EX(Ca0.59Na0.27K0.17[Al3.94Mg0.08 Feo0.07Ti0.01](Si5.85Al2.15)O20(OH)4. This sample is apparently the most Ca-rich rectorite reported to date. The Greene-Kelly test and an intercalation examination by octadecylammonium indicated that the expandable component layers were beidellitic. Assuming the tetrahedral composition of the expandable component layers are similar to the average tetrahedral composition of beidellite of (Si36Al0.4), the tetrahedral composition of the mica-like component layers was calculated to be (Si2.25Al1.75). This was closer to a brittle mica (margarite) than to a true mica. Examination of chemical data for several Ca-rectorite samples from different localities, including those from the Sano Mine, showed a trend of increasing Ca content as Al increased and Si decreased. Ca-rectorite exhibited characteristic infrared absorption bands at 480, 670–700 and 900–930 cm−1, which became more intense as Ca content increased. These bands also corresponded to major absorption bands of margarite.