Investigating dissolution of mechanically activated olivine for carbonation purposes     

Tove Anette Haug  Rolf Arne Kleiv  Ingrid Anne Munz 《Applied Geochemistry》2010

Mineral carbonation is one of several alternatives for CO₂ sequestration and storage. The reaction rates of appropriate minerals with CO₂, for instance olivine and serpentine with vast resources, are relatively slow in a CO₂ sequestration context and the rates have to be increased to make mineral carbonation a good storage alternative. Increasing the dissolution rate of olivine has been the focus of this paper. Olivine was milled with very high energy intensity using a laboratory planetary mill to investigate the effect of mechanical activation on the Mg extraction potential of olivine in 0.01 M HCl solution at room temperature and pressure. Approximately 30–40% of each sample was dissolved and water samples were taken at the end of each experiment. The pH change was used to calculate time series of the Mg concentrations, which also were compared to the final Mg concentrations in the water samples. Percentage dissolved and the specific reaction rates were estimated from the Mg concentration time series. The measured particle size distributions could not explain the rate constants found, but the specific surface area gave a good trend versus dissolution for samples milled wet and the samples milled with a small addition of water. The samples milled dry had the lowest measured specific surface areas (<4 m²/g), but had the highest rate constants. The crystallinity calculated from X-ray diffractograms, was the material parameter with the best fit for the observed differences in the rate constants. Geochemical modelling of mechanically activated materials indicated that factors describing the changes in the material properties related to the activation must be included. The mechanically activated samples in general reacted faster than predicted by the theoretical models. Mechanical activation as a pre-treatment method was found to enhance the initial specific reaction rates by approximately three orders of magnitude for a sample milled dry for 60 min in a planetary mono mill compared to an unactivated sample. Wet milling in the planetary mill did not produce samples with the same maximum reaction rate as dry milling, but wet milling in general might be easier to implement into a wet carbonation process. Mechanical activation in a planetary mill is likely to consume too much energy for CO₂ sequestration purposes, but the increase in obtained olivine rate constants illustrates a potential for using milling as a pre-treatment method.  相似文献   

2002年和2003年夏季波弗特海海冰叶绿素a和小型生物的研究     

张庆  唐学玺  刘子琳  GRADINGER Rolf  MEINERS Klaus 《海洋学报》2007,29(1):170-180

海冰在极地海洋中是个较为独特的生境,海冰卤道系统中的光照强度、温度、盐度和生存空间随着季节更替发生显著变化[1].春天,在北极新冰和多年冰的底部冰藻旺发,随后浮游植物生产力上升[2,3].  相似文献