Creation, Evaluation, Organization and Application of High temperature Experimental Data for Geo-Thermodynamic and Kinetics Database

Zhang Ronghua, Open Research Laboratory of Geochemical Kinetics,Institute of Mineral Resources, Chinese Academy of Sciences, China

Authors : Ronghua Zhang, Shumin Hu, Xuetong Zhang, and Qingjie Gong

Recent years, high-pressure science has obtained a quantum jump in performing high temperature/ultra-high pressure experiments, i.e. hundreds GPa and 6000K (or more). Combined synchrotron radiation and rapid spectrometer technique, diamond anvil cell experiments have produced lots of whacking discoveries. Simultaneously, new developed pressure cell and new design reactors have also produced new discoveries and new data. Materials of experiments are mostly collected from the earth, some from synthetical materials. In last 20 years, authors have performed lots of high temperature-pressure (T &P) experiments. New experimental data are created, which consist of 1) chemical kinetic data of minerals (and rocks) in aqueous solutions at high T & P up to 400ºC/22MPa. Authors created kinetic data of multi-oxide silicate minerals (albite, pyroxene, actinolite, etc) or oxide (Fe3O4, FeW2O4 ) at temperatures up to 400ºC, as well as carbonate, sulfide minerals, which were not published before. 2) fluid properties in the temperature range from 25 to 800ºC and pressure of 3 GPa, or over the temperature range from –110 to 1200ºC, pressures up to 1kb to 30 GPa; 3) spectrum data of the earth fluid and minerals at high T&P, which include FT-IR, VUV, Raman, EXAFS, XRD, etc. 4)Matter under extreme conditions, such as sub-critical state and the critical state matters.

Many scientists and laboratories completed a lot of high T&P experiments, and published data in literature. Evaluation of the abundant experimental data published is very significant before use of them. Evaluation methods of experimental data, e.g. properties NaCl-H2O system at high T & P and T, P, V, S (salinity) relationship is always using linear close methods. Authors suggest a non-linear method to evaluate these data, e.g. revised equations for determining the critical properties of NaCl-H2O system were fitted on previous critical data. They are  ,   and  , where T, P, V and S are the critical temperature, critical pressure, critical volume and the salinity of NaCl-H2O solution with the units of ºC, bar, cm3/g and weight percent of NaCl respectively, and Ψ=ln (S+1). These equations are valid for the S up to 36.6wt % NaCl and T up to 900ºC, which are adequate for studying supercritical fluids occurred in nature. Authors used it to calibrate Middle-Ocean-Ridge hydrothermal fluids.

Authors organize experimental data and set up 4 kinds of database: Geo-chemical kinetics; Geo-thermodynamics; maters under extreme conditions; high T&P spectrum data. We can apply those databases to predict natural and industrial processes, e.g. within the packed bed reactor, a transient material balance in a column at length Z gives:
DL  2C/Z 2 - UC/Z + r =  C/ t, where DL  refers to the combined axial dispersion and diffusion coefficient, U is the flow rate, and r is the reaction rate. It expresses a model coupling of reaction and transport in natural processes. The equation could have variable coefficients with time, and reaction parameters, which could be obtained from our database.

Keywords : Creation; Evaluation; Organization; Application; High temperature-pressure experiments, Geo-Thermodynamic and Kinetics Database