Patent ID: 8029650

Claim:
A method, relating to purifying used antifreeze comprising glycol, water, additives, and impurities, comprising the steps of: a) applying heat to at least one boiler; b) applying vacuum to the at least one boiler; c) adding used antifreeze to the at least one boiler; d) boiling off water from the used antifreeze into at least one first tank, using the at least one boiler; e) boiling off water and glycol from the used antifreeze into at least one second tank, using the at least one boiler; f) shutting off the supply of used antifreeze into the boiler; g) boiling off additional water and glycol from such used antifreeze into the at least one second tank, while simultaneously scraping at least one inside surface of the at least one boiler, until the impurities are concentrated; h) releasing the vacuum from such at least one boiler; i) dumping the impurities from the at least one boiler; and j) allowing the impurities to cool to ambient temperature, whereby at least one nontoxic, landfillable sludge is formed.