The determination of 52 elements in marine geological samples by an inductively coupled plasma optical emission spectrometry and an inductively coupled plasma mass spectrometry with a high-pressure closed digestion method

An improved analytical method to determine the content of 52 major, minor and trace elements in marine geological samples, using a HF-HCl-HNO_3 acid system with a high-pressure closed digestion method（HPCD）, is studied by an inductively coupled plasma optical emission spectrometry（ICP-OES） and an inductively coupled plasma mass spectrometry（ICP-MS）. The operating parameters of the instruments are optimized, and the optimal analytical parameters are determined. The influences of optical spectrum and mass spectrum interferences, digestion methods and acid systems on the analytical results are investigated. The optimal spectral lines and isotopes are chosen, and internal standard element of rhodium is selected to compensate for matrix effects and analytical signals drifting. Compared with the methods of an electric heating plate digestion and a microwave digestion, a high-pressure closed digestion method is optimized with less acid, complete digestion,less damage for digestion process. The marine geological samples are dissolved completely by a HF-HCl-HNO_3 system, the relative error（RE） for the analytical results are all less than 6.0%. The method detection limits are 2–40μg/g by the ICP-OES, and 6–80 ng/g by ICP-MS. The methods are used to determine the marine sediment reference materials（GBW07309, GBW07311, GBW07313）, rock reference materials（GBW07103, GBW07104,GBW07105）, and cobalt-rich crust reference materials（GBW07337, GBW07338, GBW07339）, the obtained analytical results are in agreement with the certified values, and both of the relative standard deviation（RSD） and the relative error（RE） are less than 6.0%. The analytical method meets the requirements for determining 52 elements contents of bulk marine geological samples.

Diurnal hydrological controls and non-filtration effects on minor and trace elements in stream water draining the Qiyi Glacier, Qilian Mountain

Diurnal minor and trace elements in glacial outflow water draining the Qiyi Glacier and associated hydrological controls as well as the filtration effects on water chemistry were examined. Results show that major ions, Li, St, and Ba are exported pre- dominately as mobile monovalent or divalent ions and are controlled by hydrological variations over the diurnal cycle exhibit- ing an inverse concentration with discharge, suggesting that Li, Sr, and Ba can be used as tracers in subglacial hydrological investigations. Conversely, other elements （e.g. Fe, Al, and Cr） exhibit variations that are not strongly correlated with the dis- charge reflecting the physicochemical controls. The non-filtered operation appears not to strongly influence Sr and Ba, but has an effect on some elements such as Fe, Al, V, Ti, and Co, indicating that these changed elements are transported in particulate forms and thus their concentrations are highly dependent on particulate numbers in solutions. This implies that the immediate filtration after sampling is essential in hydrochemical studies at Alpine glacial basins due to subsequent mineral dissolution.

Demineralization of Gondwana coal with Pseudomonas mendocina strain B6-1： a case study of coal from Gopinathpur top and bottom seams of Mugma mine, Dhanbad, Jharkhand （India）

In the present investigation an attempt has been made to demineralize the Gondwana coal of Gopinathpur top and bottom seams of Mugma mine, Raniganj coalfield, Dhanbad with the help of Pseudomonas mendocina strain B6-1. The change in the amount of ash yield and decrease in the concentration of selected minor elements like Na, K, Mn and Ca and environmentally sensitive selected trace elements such as Cd, Pb, Se, Ni, Mn, and Zn have been studied as a function of time of bacterial treatment as well as with variation in the bacterial biomass. After 28 days of bacterial treatment there was variable amount of decrease observed in ash yield as well as in the concentration of minor and trace elements. The removal of the elements was further enhanced with the increase in the bacterial biomass from 10 to 25 mg/mL. Due to over exploitation of superior grade coals in the country, the remaining coal resources, available for current use, are inferior in grade and contain high level of impurities and there is ample scope of bio-beneficiation of these coals using bacterial biomass.

Contribution of T_1 Precipitates to Strength in Two Kinds

The behavior of interaction between dislocation and T 1 plate was observed and analyzed by means of TEM technique in Al Li alloys of 2090 and 2090+Ce. The observation results show that the interaction between dislocation and T 1 plate is a mix type of shearing and Orowan looping, and the physical models are established by theory of precipitates strengthening. The results of calculation illustrate that the contribution of T 1 plate is up 30%～60% to the overall critical resolved shear stress (CRSS). The role of T 1 plate is enhanced with aging time in the material aged 3～48 h at 190℃, but this enhancing effect becomes gentle on overaged condition. The strengthening effects of T 1 plate in 2090 and 2090+Ce alloys are little different on under aged condition, but the strengthening effects of T 1 precipitates in alloy 2090+Ce is little bigger than that of 2090 on overaged condition, especially the cutting mechanism is only considered. The difference between strengthening effects of matrix in two alloys is about 3.2 MPa on underaged condition and 8.7 MPa or so on overaged condition.