Study of oxidative desulphurization process of coal with different metamorphism degrees

The oxidative desulphurization process of coal with different metamorphism degrees treated by an air-steam mixture has been studied.It has been shown that the pyrite present in black coal and anthracite is oxidized with the sulphur dioxide formation,and the process chemical mechanism does not depend on the quality of organic matter.The medium-metamorphized coal,capable of turning into a plastic state and cake in the range of investigated temperatures(350～450 ℃),is desulphurized with the greatest difficulty.The chemical mechanism dealing with the transformations of pyritic sulphur present in brown coal differs from similar processes taking place in black coal and anthracite,because FeS2 is converted with hydrogen sulphide formation at desulphurization.     

A PRELIMINARY RESEARCH ON WEATHERING PROCESS IN CASEY STATION, EAST ANTARCTIC

The chief aim of this preliminary work is to investigate the weathering process of the bed rock and moraine in Antarctic by the method of sedimentology. Microfractures, the depth of which is less than 1 cm, and macrofissures are formed through frost weathering process. The chemical composition of the weathering products are observably related to their size due to migration process. Weathering materials are relatively rich in rare-earth elements of Ce family. Weathering clay minerals are mainly illite hydromica which can considerably absorb the elements of Ti, K, Cs, Rb, Sc, Sb, As and Fe. The weathering crust of the bed rock has hardly any CaCO_3 component, it belongs to primigenial debris weathering crust, with only a slight As pollution.     

Chemical-physical aspects of formation and evolution of phase structure in multi-polymers: Intensity fluctuation, phase structure and its fractal characteristics in blends of isotactic polypropylene with poly(cis-1,4-butadiene) rubber

This paper studies the formation and evolution of phase structure of isotactic polypropylene/poly(cis-1,4-butadiene) (iPP/PcBR) blends during molten and mixing in a visual mixer by on-line analysis of the small angle light back scattering. The density fluctuation of iPP/PcBR blends during molten and mixing is discussed using the integral-intensity Js, of the scattering intensity of the blends. The "invariant" Q, which shows fluctuation of the system, is calculated by data of the small angle light back scattering, and the variation of Q with the blending time, temperature and shear rate during molten and mixing in iPP/PcBR blends is discussed. The structure parameters which characterize dimensions of phase in the blends, as the correlation distance ac, and the average chord lengths of two-phase, as li PP and lP cBR, are calculated by data of scattering intensity. The average diameters dp of dispersed phases are calculated from SEM images. The variation of ac, dp, li PP and lP cBR with the blending time and compositions in the blends during molten and mixing is discussed. The scale law is analyzed to find multi-scale characteristics in this system. The generalized fractal dimension Dp is calculated and the relation of Dp with generalized entropy function is discussed to determine that Dp is state function and the physical significance of Dp is the same as that of the generalized entropy function.     

Structure and Catalytic Behaviour of Saponite and Its Cross-Linking Product

Synthetic saponites have been intercalated with hydroxyl aluminium oligomers and characterized with several techniques. The basal 001 peak of the pillared saponite (PS) is 1. 8 nm. The amount of the aluminium in the tctrahedral sheet is correlative with cross-linking density. The sheet-to-pillar linkage mode may be Si-O-AlpⅥ. The acid sites in pillared saponite may locate either at surface of clay or at that of pillar. The cumene conversion is relative to accessible acid sites on the surface of PS. The pillar density in the PS has an effect on the pore structure which is correlative with shape selectivity during the reaction between ethanol and ammonia.     

Kinetic spectrophotometric method for the determination of selenium(IV) by its catalytic effect on the reduction of spadns by sulphide in micellar media

A simple kinetic spectrophotometric method was developed for the determination of ultratrace amounts of Se(IV). The method is based on the reduction of spadns by sulphide in micellar media. The reaction was monitored spectrophotometrically by measuring the decrease in the absorbance of spadns at 515 nm with a fixed-time method. The decrease in the absorbance of spadns is proportional to the concentration of Se(IV) in the range 0.5–100 ng/mL with a fixed time of 2.5–7.0 min from the initiation of the reaction. The limit of detection is 0.3 ng/mL Se(IV). The relative standard deviation for the determination of 0.02 and 0.10 μg/mL Se(IV) was 2.10 and 1.95%, respectively. The method was applied to the determination of Se(IV) in water. The text was submitted by the authors in English.     

A NEW POLYMERIC FLAME RETARDANT ADDITIVE FOR NYLON

The present paper deals with the use of a new polymeric flame retardant material, polyphenylene sulphide (PPS) for plastics. Incorporation of 15—20% PPS into nylon-6 has provided UL V-0 rating for the system and there is enhancement in tensile and flexural properties. The results obtained on the thermal, crystallization and flow characteristics of the nylon-PPS system upto a loading of 40% PPS are also discussed.     

Comparison Between Catalytic Activity and Activity Changes During Denaturation by Guanidine Hydrochloride of Enzymes in Crystalline State and in Solution

The catalytic activity and activity changes during denaturation by guanidine hydrochloride of glyceraldehyde-3-phosphate dehydrogenase,lactate dehydrogenase and α-chymotrypsin in crystalline state and in solution have been compared.The catalytic activities are lower in crystalline state than in solution. Enzymes in crystalline state are more stable than in solution during denaturation by guanidine hydrochloride.Ammonium sulfate has different effects on catalytic activities of different enzymes and shows protection on all enzymes studied during denaturation by guanidine hydrochloride.The protection is more obvious at high concentrations of guanidine hydrochloride than at low concentrations.It is suggested that the flexibility or mobility of enzyme is required for the catalytic activity and related to the stability of enzymes. Enzymes with less flexibility or mobility are more stable.     

TECTONIC FRAMEWORK OF THE CONTINENTAL BASEMENT OF SOUTHEAST CHINA

The chronology and tectonic evolution model of the continental basement in southeast China margin is an important debatable geological subject. The Cathaysia is shown in this paper to be in accordance with many geological facts and also with the age data obtained by multi-dating method. Its age has been determined to range from 900 to 2000 Ma. The age of the unconformity plane in the Cathaysia is 1400 Ma. The collision and suture between the Jiangnan oldland and the Cathaysia took place during the early Jinning Period. Toward Jiangxi, Hunan, Guangdong and Guangxi, these two continents gradually opened to form a residual oceanic basin. The sedimentation centre of the basin continuously migrated southwestward from the Jinning through the Caledonian Period, and finally closed in the Guangxi Movement and Dongwu Movement. The drift-rotation of the Cathaysia after the Jinning Period has been inferred.     

Effect of a Hybrid Zinc Stearate-Silver System on the Properties of Polylactide and Its Abiotic and the Biotic Degradation and Antimicrobial Activity Thereof

This work investigates the degradation and properties of a thermoplastically prepared composite comprising a polylactide/hybrid zinc stearate-silver system.The influence of the zinc stearate-silver system on the properties of the composite is investigated by electron microscopy,differential scanning calorimetry and tensile tests.Furthermore,the antimicrobial activities of the systems are examined.The degradation behaviour of the composites is studied in both abiotic and biotic(composting) environments at an elevated temperature of 58 °C.The results reveal good dispersion of the additive in the PLA matrix,a stabilizing effect exerted by the same on the polylactide matrix during processing,and slight reduction in glass transition temperature.The zinc stearate-silver component also reduces brittleness and extends elongation of the composite.Abiotic hydrolysis is not significantly affected,which is in contrast with pure PLA,although mineralization during the early stage of biodegradation increases noticeably.The composite exhibits antimicrobial activity,even at the lowest dosage of the zinc stearate/silver component(1 wt%).Moreover,Ag and Zn contents were found to be present in the composite during abiotic hydrolysis,which was demonstrated by minimal diffusion of Ag ions from the matrix and very extensive washing of compounds that contained Zn.     

CHANGES OF SEDIMENTARY ENVIRONMENT SINCE THE LATE PLEISTOCENE IN VESTFOLD HILLS AREA, ANTARCTICA

The Vestfold Hills area was a shallow-sea sedimentary environment in the interglacial stage (50,000—25,000 yr B.P.) of the last glacial period of the Late Pleistocene, and later became a glaciofluvial environment. This marine sedimentary plain was covered by glaciers at the time of 31,000—11,000 yr B.P. After the last glacial period (6500—3500 yr B.P.), the retreat of ice sheets in this area resulted in the formation of lakes and lagoons, followed by alternating sedimentation of three-times sub-turbidity current and two-times ice-melt water. Sulphate-Glauber salt was deposited in the inland depressions. The advance of the ice sheets in this area during the neo-ice age (2800 yr B.P.) resulted in three parallel moraine terraces consisting of boulders and coarse sands composed mainly of hornblende, and subordinately of garnet and magnetite. During this period a Si-AL-chloride detrital weathering crust was developed on hyperthenite with schistose actinolite. In addition to physical weathering (e.g. frost     

乌江流域沉积岩风化过程中稀土元素的富集与释放

以乌江流域石灰岩、白云质灰岩、白云岩、硅质岩、页岩和砂岩等沉积岩的13条风化剖面为对象，运用R型分层聚类分析和质量平衡计算方法，研究了这些岩石风化过程中稀土元素（REE）的富集与释放及其对植物生长和河水REE分布的影响，目的是为河水物质来源研究和为农业生产提供依据。结果表明：（1）乌江流域石灰土中REE的富集程度显著高于各自母岩、黄壤、上陆壳（UCC）、中国土壤（CS）和世界土壤（WS）；（2）沉积岩风化过程中REE的富集特征和机制可能与母岩中REE分布特征以及风化剖面中有机质、铁（氢）氧化物和粘土矿物的吸附有关；（3）沉积岩风化过程中释放的REE可为植物吸收利用；（4）石灰岩等沉积岩风化过程中REE和F。等元素的释放对河水溶解态REE的分布有重要影响。     

Biogeochemistry of trace and major elements in a surface environment (volcanic rock,soil, mosses,lichens) in the S. Miguel Island,Azores, Portugal

The distribution of the chemical element during weathering of trachyandesite in S. Miguel Island (Azores, Portugal), and in mosses and lichens growing on these rocks, was studied using instrumental neutron activation analysis. A general enrichment of rare earth elements (REEs), a Ce positive anomaly (partial oxidation after primary apatite dissolution) and a Eu negative anomaly (Eu²⁺ in plagioclases/clay minerals) are observed with increasing weathering. Mosses and lichens are Ce and Eu depleted, indicating that the main REE uptake is done via absorption from REE³⁺ secondary phosphates, probably together with P (essential nutrient). Zn, Br and Sb show higher enrichment factors in lichens and mosses.     

花岗岩风化壳稀土存在形态分析方法研究

研究了一个测定花岗岩风化壳中REE存在形态的方法。以0.2 mol/L MgCl_2,2.5 mol/LHCl,0.5 mol/L NaOH及含15%H_2O_2的2.5 mol/L HCl连续提取风化壳试样中的稀土。经X射线衍射、红外光谱及剖面试样测试,论证了每一提取态的内涵,提出了花岗岩风化壳中非原生矿物相稀土存在活性态、铁铝共沉淀态和有机结合态的新认识。     

Neutron activation analysis on sediments from Victoria Land,Antarctica: multi-elemental characterization of potential atmospheric dust sources

The elemental composition of 40 samples of mineral sediments collected in Victoria Land, Antarctica, in correspondence of ice-free sites, is presented. Concentration of 36 elements was determined by instrumental neutron activation analysis, INAA. The selection of 6 standard reference materials and the development of a specific analytical procedure allowed to reduce measurements uncertainties and to verify the reproducibility of the results. The decision to analyze sediment samples from Victoria Land ice-free areas is related to recent investigations regarding mineral dust content in the TALos Dome ICE core (159°11′E; 72°49′S, East Antarctica, Victoria Land), in which a coarse local fraction of dust was recognized. The characterization of Antarctic potential source areas of atmospheric mineral dust is the first step to identify the active sources of dust for the Talos Dome area and to reconstruct the atmospheric pathways followed by air masses in this region during different climatic periods. Principal components analysis was used to identify elements and samples correlations; attention was paid specially to rare earth elements (REE) and incompatible/compatible elements (ICE) in respect to iron, which proved to be the most discriminating elemental groups. The analysis of REE and ICE concentration profiles supported evidences of chemical weathering in ice-free areas of Victoria Land, whereas cold and dry climate conditions of the Talos Dome area and in general of East Antarctica.     

Proton chemical polarisation,autocatalysis and frontal kinetics of the oxidation of dialkylsulphides with nitric acid

The oxidation of dimethyl sulphide to dimethylsulphoxide with nitric acid displays CIDNP effects of protons and the phenomenon of frontal kinetics. The process is autocatalytic, with N₂O₄ as the catalyst and the primary oxidant of sulphide. In the presence of the inhibitor (methylmercaptan) the frontal reaction takes place: in purified samples—the usual volume reaction. The interaction of ethyl, n-propyl and n-butyl sulphides with NO₂ is accompanied by integral polarisation of the α-CH₂-protons. In all the cases sulphide is negatively polarised and sulphoxide positively polarised. The reaction mechanism proposed includes the formation of a radical pair during the interaction of sulphide with N₂O₄. Disproportionation of the radical pair leads to the formation of polarised sulphoxide and the decay results in re-generation of sulphide. The rate of oxidation of sulphide during the volume reaction is proportional to the product polarisation.     

Speciation of Heavy Metals in Finnish Lake Ores; Selective Extraction Analysis

Abstract

The speciation of Fe, Mn, Co, Cu, Ni, and Zn are studied in Finnish lake ores from areas where weathering of black schists and mica schists, containing abundant sulphide minerals, causes natural pollution by heavy metals.     

Assessment of bioaccumulation of REEs by plant species in a mining area by INAA

Native plant species, lichens and tailings, sampled from a copper?Csulphide mining area located in southern?Ceastern Portugal, were analysed by neutron activation analysis (INAA) for determination of rare earth elements (REEs). Values of ??REEs and individual REEs concentration of tailing samples are higher than those of natural background concentrations. The higher values of REEs are found in modern slags and the mixture of oxidized gossan and sulphide disseminated country rocks when compared with the alluvial sediments contaminated by mine tailings. The total concentrations of light REEs are higher than those of heavy REEs in all tailing samples. Distribution patterns of PAAS-normalized REEs in mine tailings show slightly LREE enriched and flat HREE pattern with negative Eu anomaly. Lichens accumulated higher concentration of lanthanides than vascular plants. The elevated levels of REEs in lichen, native plant species and tailing samples reflect the contamination of REEs in S?o Domingos mining area. The Carlina corymbosa, Erica australis and Lavandula luisierra accumulated the higher amounts of La, Ce and other REEs than the other plant species grown in this mining area.     

Rare earth elements distribution in clay zones of sedimentary formation, Pondicherry, south India

Concentrations of five rare earth elements (REE) were measured in clay samples of a deep bore hole comprising major aquifers of Pondicherry region, south India in order to investigate the geochemical variations among various litho-units. Clay samples from Cretaceous formation show distinct gray to black color whereas Tertiary deposits have clays with color varying from pale yellow to brown to gray. All measured REEs exhibit lower concentrations than Upper Continental Crust (UCC) average values. Large variations in REEs contents were observed in different sedimentary formations (Tertiary and Cretaceous). Chondrite normalized ratio of La/Lu and Eu/Eu* indicate that the clays are derived from weathering of felsic rock and possibly under humid climate. All the samples showed positive Eu anomaly in North American Shale Composite (NASC) normalized plot which shows plagioclase feldspar as the major contributor to these clays. Positive Eu anomaly is also an indication of reduced condition of the formation.     

母岩高铀离子型稀土矿采区的放射性污染风险浅析

铀与稀土元素同属大离子亲石元素,尤其与钇组稀土关系更密切,因此南岭高铀花岗岩往往同时是铀和离子型重稀土矿床的成矿母岩。国内外研究资料表明,高铀花岗岩中的铀主要以原生铀的形式存在于晶质铀矿中,在强烈风化过程中大部分发生活化转移,而采矿活动对此有显著促进作用;国外众多含铀湿地的发现及其研究资料表明,山区湿地是铀的"高效过滤器"和"沉淀池",花岗岩风化转移到水体中的微量铀经长期累积,可在湿地富有机质土壤和沉积物中富集至(3000~4000)×10^-6,而采矿和农垦活动可将湿地经几千年累积富集起来的铀释放到居民的生活环境中,因而被视为是一种环境风险。因此建议加强母岩高铀离子型稀土矿区的湿地放射性调查和环境保护,以保障湿地对重金属的天然过滤功能,避免湿地束缚铀的释放,这对保护矿区水质和生态环境都具有重要意义。     

Neutron induced prompt gamma-ray and instrumental neutron activation analyses of urban estuarine sediments

Neutron induced prompt -ray analysis (PGA) and instrumental neutron activation analysis (INAA) have been applied to the sediments collected from the Tama River estuary in Tokyo, Japan. The vertical distribution of 24 elements in the sediments was determined and the factors goveming the vertical profiles have been discussed. Major elements are distributed depending on weathering that proceeds much with increasing depth. Cadmium is highly concentrated in the deeper layer where sulphate ion is reduced to hydrogen sulphide. The distribution of several rare earth elements is also presented