| abstract |
A method of maintaining foundry molding sand and/or a foundry core sand compositions relatively free of benzene and/or total quantity of volatile organic compounds (total VOCs) at 1800° F. and 1 atmosphere pressure by periodically analyzing the sand mold and/or sand core compositions for one or more aromatic hydrocarbons, such as benzene and/or other single ring aromatic hydrocarbons, such as toluene, and/or extractable organic matter (EOMs). If the sand composition is determined by analysis, e.g., by volatilizing the hydrocarbons and passing the volatilized material through a gas chromatograph, or by thermogravimetric analysis, to contain more than a desired amount of aromatic hydrocarbons, e.g., more than about 0.1 mg/g; and/or more than a desired amount of total VOCs, or extractable organic matter (EOM), e.g., more than about 0.5 mg/g total VOCs at 1800° F., the sand composition then can be treated by sand replacement; for hydrocarbon removal or hydrocarbon oxidation, such as by solvent extraction, or oxidation, e.g., by contact with O 3 in water solution; or by adding activated carbon or generating activated carbon in-situ with carbon, graphite acid as humic-containing ore. The treated sand then is reused to form a foundry sand mold and/or sand core for reduced emissions. |