The Dow Chemical Company

Robert J Nankee

Thomas A Vivian

Kenneth O Groves

E Richard Randolph

Chlorinated solvents are removed from vapor vent streams containing the solvent, water and non-condensable vapors by contacting the vent stream with a liquid spray of precooled chlorinated solvent at a temperature less than the freezing point of water. The solid ice floats on the liquid chlorinated solvent and can be readily separated therefrom.

Process for reduction of chlorinated solvent emissions

In an investment casting process wherein molds or cores are prepared by forming them around a polymer pattern and then dissolving the pattern with a solvent, solvent losses can be reduced by heating the mold or core before contacting it with the solvent to reduce the amount of solvent adsorbed in the mold or core. An improved process comprises: (a) forming the mold or core around the pattern; (b) heating the mold or core; (c) dunking or spraying the mold or core with the solvent until the pattern is dissolved; (d) placing the mold or core in a drying chamber in the path of circulating heated air; (e) cooling the air to condense the solvent; (f) recovering the condensed solvent; and (g) reheating the air until it is no longer saturated with solvent and recycling the air to the drying chamber. The preliminary heating step can reduce solvent losses by 66 percent and the entire improved process can reduce solvent losses by about 90 percent.

Process for producing molds or cores for investment casting with reduced

A process for enhancing coal by removing the gangue (rock, shale, iron pyrites and the like) associated with the mined coal as it comes from the crushers before further treatment. The process described slurries the crushed run of the mine (ROM) coal with a heavy medium, such as perchloroethylene, for a short period of time at ambient or below temperatures, (i.e. slurry times of 5-30 minutes and temperatures of 90.degree. C. to below -10.degree. C.); thereafter allowing, in a substantially quiescent environment, the solids to settle or float as their inherent densities are greater or lesser respectively than the density of the heavy medium. After settling the float solids (mostly coal of lower sulfur and ash content) are separated from the heavy medium as one stream and the sink solids (mostly the gangue) as a second stream. These solids are each washed with hot (90.degree. C.-100.degree. C.) water and the vapor azeotrope which forms from the water and heavy medium mixture (azeotrope) removed. The now water wet solids are separated from the body of hot water and sent for further processing or loading. The solids, both the coal and the gangue, have a heavy medium content of less than about 400 parts heavy medium per million parts solids.

Coal enhancement process and equipment

A method of reclaiming clear PET resin from bottles and other containers is disclosed. PET resin contaminated with a hot melt type polyethylene copolymer based glue is treated with a chlorinated solvent and optionally subjected to azeotropic drying.

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Midland, MI, United States of America

Robert J Nankee