Carbonation of Rock Minerals by Supercritical Carbon Dioxide at 250 degrees C.

Sugama, T. ; Ecker, L. ; Butcher, T.

Brookhaven National Laboratory

关键词: By-Products;    Anorthite;    Quartz;    Feldspars;    Sodium;   

DOI  :  10.2172/984434
RP-ID  :  BNL--93722-2010-IR
RP-ID  :  DE-AC02-98CH10886
RP-ID  :  984434

美国|英语

来源: UNT Digital Library

【 摘 要 】

Wet powder-samples of five rock minerals, granite, albite, hornblende, diorite, and biotite mica, were exposed in supercritical carbon dioxide (scCO2) for 3 days at 250 C under 17.23 MPa pressure, and then the susceptibility of the various crystalline phases present in these mineral structures to reactions with hot scCO2 was investigated by XRD and FT-IR. The anorthite present in diorite was identified as the most vulnerable phase to carbonation. In contrast, biotite displayed a great resistance, although its phase was transformed hydrothermally to sanidine and quartz. Granite comprised of two phases, anorthoclase-type albite and quartz. The carbonation of former phase led to the formation of amorphous sodium and potassium carbonates coexisting with the clay-like by-products of the carbonation reaction. The reactivity of quartz to scCO2 was minimal, if any. Among these rock minerals, only hornblende formed crystalline carbonation products, such as calcite and magnesite after exposure, reflecting the likelihood of an increase in its volume. Based upon the feldspar ternary diagram, the carbonation rate of various different minerals in the plagioclase feldspar family depended primarily on the amount of anorthite. On the other hand, alkali feldspar minerals involving anorthoclase-type albite and sanidine had a lower reactivity with scCO2, compared with that of plagioclase feldspar minerals.