Process for treatment of aqueous solutions of polyhydric alcohols
AssigneePrestone Products Corporation
InventorsPeter M. Woyciesjes, Aleksei V. Gershun, Stephen M. Woodward
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Abstract
The process relates to the treatment of aqueous solutions of polyhydric alcohols to remove heavy metal components, oils, organic contaminants and, optionally, water. The process is particularly well suited for use in the treatment of spent antifreeze/coolant from the cooling systems of internal combustion engines.
Claims30
A process for the treatment of an aqueous antifreeze/coolant composition obtained from the cooling system of internal combustion engines containing between about 5 weight percent and about 95 weight percent of a polyhydric alcohol selected from the group consisting of ethylene glycol, diethylene glycol and propylene glycol and mixtures thereof and containing at least one solubilized heavy metal species selected from the group consisting of lead, molybdenum, iron, zinc, and copper, wherein said process comprises the following steps:
- (i) adjusting the pH of said aqueous antifreeze/coolant composition to between about 4.0 and about 7.5 by addition of an effective amount of a pH adjusting agent to form a pH-adjusted composition and adding an effective amount of a precipitating agent effective in forming a precipitate of said heavy metal species;
- (ii) adding to said pH-adjusting composition an effective amount of at least one of a coagulating agent and a flocculating agent to form a heavy metal containing precipitate;
- (iii) passing said pH-adjusted composition of step (ii) and said heavy metal containing precipitate through a first filtration means capable of removing species having a size greater than about 100 microns;
- (iv) passing said pH-adjusted composition of step (iii) through a second filtration means capable of removing species greater that about 40.0 microns;
- (v) passing the pH-adjusted composition from step (iv) through an organic separation means effective in removing organic compounds from said polyhydric alcohol of said pH-adjusted composition;
- (vi) passing said pH-adjusted composition through a third filtration means capable of removing species greater than about 5 microns;
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- (vii) passing said pH-adjusted composition of step (vi) through a cation exchange means effective in the removal of at least one solubilized heavy metal species present in said pH-adjusted composition from step (vi).
In a process for the removal of an antifreeze/coolant containing between about 5 wt. % and about 95 wt. % of a polyhydric alcohol and at least one heavy metal from the cooling system of an internal combustion engine and replacement of said antifreeze/coolant after treatment wherein said process comprises the steps of:
- (a) adjusting the pH of said aqueous antifreeze/coolant to between about 4.0 and about 7.5 by addition of an effective amount of a pH adjusting agent to form a pH-adjusted composition and adding thereto an effective amount of a precipitating agent for said heavy metal;
- (b) adding to the pH-adjusted composition an effective amount of coagulating agent and an effective amount of a flocculating agent to form a precipitate containing at least one heavy metal;
- (c) passing the pH-adjusted composition through a first filtration means to remove heavy metal-containing precipitate from said pH-adjusted composition;
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- (d) adding to the filtered composition of step (c) an effective amount of corrosion inhibiting agents for said cooling system.
Dependencies are inferred from the claim text.