Chemical kinetics of Ca / Mg elements from calcite / dolomite in carbonic acid solution

This paper provides an experimental support for increasing the flow conductivity of coal reservoir by identif- ying the interaction characteristics between CO2 ,water and calcite / dolomite. Under the research background on Yuwu and Sihe Mines in Qinshui Basin,with the chemical dynamical experiment between carbonic acid solution and calcite /dolomite,based on the experimental tests of atomic absorption spectrometric analysis (AAS),energy spectrum analysis (EDS),X-ray diffraction analysis (XRD) and scanning electron microscope (SEM),the study investigated the relea- sing rule of Ca2+ / Mg2+ in reaction solution, solid state element change rule, crystal variation and surface structure change,established the reaction kinetics model of calcite and dolomite. The results show that the dissolved quantity of Ca2+ in calcite is more than that of dolomite,and the dissolved quantity of Ca2+ in dolomite is more than that of Mg2+ . The contents of Ca2+ and Mg2+ increase first and then decrease with reaction time and the data fluctuate greatly. The ion contents increase with decreasing pH value,and decrease with increasing temperature,but it has little influence on the content of Mg2+ . The contents of calcium and magnesium in solid phase decrease first then increase,and the inten- sity of characteristic peaks of crystal reduces first then enhances. The established chemical kinetics model shows that the higher the temperature,the lager the reaction order,and the concentration has a great influence on chemical reac- tion. When pH value is low,or apparent activation energy is low,the reaction increases.