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The positive correlations between whole-rock concentrations of Cr and Os, Ir and Ru (referred to collectively as iridium-like platinum-group elements, IPGE) in both sulphide-poor plutonic and volcanic rocks suggest that chromite contributes to the collection of these elements during the early stages of sulphide-undersaturated magma differentiation. However, it is not clear whether these correlations are the result of IPGE partitioning into chromite or whether other minerals are involved. Positive correlations between MgO and IPGE have been observed, suggesting that these elements could be incorporated into olivine as well as into chromite. Alternatively, given the siderophile nature of IPGE, they may crystallize as discrete minerals together with chromite, as suggested by the presence of platinum-group minerals in chromite-rich rocks such as mantle podiform and crustal stratiform chromitites. To investigate the effect of chromite crystallization on the distribution of IPGE and Rh in picritic magmas, we have determined the content of these elements in chromites from the Emeishan Large Igneous Province (southwestern China) by in situ laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The time-resolved analysis signals are generally uniform, indicating that the IPGE and Rh are homogeneously distributed within the chromite crystals. The median concentrations are 30 ppb Os, 23 ppb Ir, 248 ppb Ru and 21 ppb Rh. The incorporation of Rh in chromites appears to be influenced by the oxidation state of the magma from which they crystallize because there is a positive correlation between the degree of inversion of the chromite structure [expressed by Fe3+/(Cr + Al + Fe3+)] and the Rh content of the analyzed crystals. In contrast, the enrichments of Os, Ir and Ru in chromites appear to be controlled by other parameters such as temperature or the S content of the magma. Based on empirical calculations, we determined that partition coefficients between chromite and melt are higher for Ru (127) than for Os (23), Ir (27) and Rh (32). Despite these high partition coefficients, mass-balance calculations show that chromite does not account for all the IPGE and Rh concentrations in the rocks, with chromite accounting for maxima of 84, 49, 22 and 20% of the whole-rock Ru, Rh, Ir and Os budgets, respectively. In situ LA-ICP-MS and scanning electron microscopy analyses reveal the presence of micrometric-sized PGE-rich minerals, including laurite (RuS2), Os-Ir 6 Ru alloys, sperrylite (PtAs2) and Pt-Fe (6 IPGE and Rh) alloys, in association with chromite crystals. The presence of these minerals may account for the balance of IPGE and Rh. Alternatively, if IPGE and Rh are compatible with olivine, the balance may be accounted for by the large amount of olivine crystals found in the Emeishan picrites. Based on numerical modelling, we conclude that chromite, olivine and platinum-group minerals all contribute to the collection of IPGE and Rh during the early stages of picritic magma differentiation. Also, we establish that the preferential incorporation of Ru into chromite is responsible for the negative Ru anomalies observed in the PGE patterns of the Emeishan flood basalts. On the other hand, the relative importance of olivine and platinum-group minerals in controlling IPGE and Rh remains uncertain and is a key subject for further investigation. [ABSTRACT FROM AUTHOR]

Abstract: The application of ruthenium-ion-catalyzed oxidation (RICO) products of asphaltenes of heavy oils in Lunnan and Tahe oilfields and Well TD2 in oil–oil and oil–source correlations was explored. The RICO products included n-alkanoic acids, α,ω-di-n-alkanoic acids, branched alkanoic acids, tricyclic terpanoic acids, hopanoic acids, gammacerane carboxylic acid, regular sterane carboxylic acids and 4-methylsterane carboxylic acids. The n-alkyl chains and biomarkers bonded on the asphaltenes were uneasily to be biodegraded. The distribution and absolute concentration of n-alkanoic acids in RICO products of heavy oils in Lunnan and Tahe oilfields are different from those of Well TD2. The biomarkers bonded on the asphaltenes, especially steranes, have a similar distribution to that of the counterparts in the saturated fraction. The sterane carboxylic acids and 4-methylsterane carboxylic acids in the RICO products of heavy oils in Lunnan and Tahe oilfields, dominated by C30 sterane and C31 4-methylsterane carboxylic acids, respectively, are significantly different from those of Well TD2, whose dominating sterane and 4-methylsterane carboxylic acids are C28 sterane and C29 4-methylsterane acids, respectively. The RICO products of asphaltenes further indicate that the Upper Ordovician may be the main source rock for the twice charged hydrocarbon of heavy oils in Lunnan and Tahe oilfields. [Copyright &y& Elsevier]

Discusses the use of ruthenium-ion-catalyzed oxidation (RICO) to investigate asphaltenes from three oils with the same origin in the Juquan Basin and three oils with the same origin but with different degree of biodegradation in the Turpan Basin, Northwest China. Description of results, which showed that the biomarkers bonded on the asphaltenes with the same origin is similar and is correlated with the free biomarker in saturates; How the biomarker and benzenecarboxylic methyl easter reflecting the structure of the asphaltenes after RICO should provide a new way for oil-source correlation and should be specially useful for severely biodegraded oil-source correlation.

Structural characterization of four Chinese coal macerals has been undertaken by integration of results from [sup 13] C nmr and ruthenium ion catalyzed oxidation. The average molecular structures were obtained from conventional solid state [sup 13] C-CP/MAS nmr and dipolar dephased [sup 13] C-CP/MAS nmr, using a peak deconvolution approach based on chemical shifts of standard compounds. Detailed molecular information of the macerals has been gained from the chemical degradation using ruthenium ion catalyzed oxidation (RICO). [ABSTRACT FROM AUTHOR]

Herein, a duckweed biocrude produced from the hydrothermal liquefaction of Lemna minor was treated in subcritical water with added H₂. Effects of several different commercially available materials such as Ru/C, Pd/C, Pt/C, Pt/γ-Al₂O₃, Pt/C-sulfide, Rh/γ-Al₂O₃, activated carbon, MoS₂, Mo₂C, Co-Mo/γ-Al₂O₃, and zeolite on the yields of product fractions and the deoxygenation, denitrogenation, and desulfurization of biocrude at 350°C were examined, respectively. All the materials showed catalytic activity for deoxygenation and desulfurization of the biocrude and only Ru/C showed activity for denitrogenation. Of those catalysts examined, Pt/C showed the best performance for deoxygenation. Among all the upgraded oils, the oil produced with Ru/C shows the lowest sulfur, the highest hydrocarbon content (25.6%), the highest energy recovery (85.5%), and the highest higher heating value (42.6 MJ/kg). The gaseous products were mainly unreacted H₂, CH₄, CO₂, and C₂H6., (Copyright © 2014 Elsevier Ltd. All rights reserved.)