Carbon Dioxide Soluble Binders for Metal Casting Applications

摘要

Conventional binders for metal forming applications are associated with a number of environmental problems such as emissions from binder removal and the production of waste materials. Here we examine several materials as possible binder candidates for a new technology wherein the binder can be recovered and recycled by supercritical carbon dioxide. The candidates include an acetylated sugar and several tert-butylated aromatics. The phase behavior data of these candidate materials in carbon dioxide, and disassociation kinetics of sand mold in supercritical, or near-critical carbon dioxide are presented. The phase behavior studies, which were conducted in the range of 293-328 K and 2-18 MPa, showed solubility values up to 30 wt percent in supercritical carbon dioxide. Disassociation experiments demonstrated that supercritical carbon dioxide can extract the binders from bound-sand mold samples of about 1 cm~3 in less than 5 minutes, under moderate temperatures and pressures.