Process for the separation of plastics by flotation
First Claim
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1. A process for separating off polyester plastic from a plastics mixture containing polyester and polyvinyl chloride plastics, which comprises:
- treating the plastics mixture with a sufficient amount of an aqueous alkaline solution to render the polyester plastic more hydrophilic than the polyvinyl chloride plastics, suspending and subjecting to froth flotation the thus-treated plastics mixture in a flotation zone, said froth flotation being carried out in the presence of at least one flotation froth-forming agent and a collecting agent comprising natural oils having a chain length of 8 to 20 carbon atoms or fatty acids having 8 to 20 carbon atoms, said at least one flotation froth forming agent being present with said collecting agent in a ratio range of from 9;
1 to 1;
9, whereby the polyester remains as the residue and the polyvinyl chloride becomes recoverably in froth floated form as a foam product, and separating off the polyester from the polyvinyl chloride by isolating the residue and the foam product.
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Abstract
The invention relates to a process for separating off polyester plastics from a mixture of polyester, polyvinyl chloride and, if present, other plastics, wherein in the flotation the polyester remains as the residue and the polyvinyl chloride and, if present, other plastics are recovered in floated form, which comprises treating the mixture of plastics with an aqueous alkaline solution and separating off the polyester from polyvinyl chloride and, if present, other plastics by flotation.
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12 Claims
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1. A process for separating off polyester plastic from a plastics mixture containing polyester and polyvinyl chloride plastics, which comprises:
treating the plastics mixture with a sufficient amount of an aqueous alkaline solution to render the polyester plastic more hydrophilic than the polyvinyl chloride plastics, suspending and subjecting to froth flotation the thus-treated plastics mixture in a flotation zone, said froth flotation being carried out in the presence of at least one flotation froth-forming agent and a collecting agent comprising natural oils having a chain length of 8 to 20 carbon atoms or fatty acids having 8 to 20 carbon atoms, said at least one flotation froth forming agent being present with said collecting agent in a ratio range of from 9;
1 to 1;
9, whereby the polyester remains as the residue and the polyvinyl chloride becomes recoverably in froth floated form as a foam product, and separating off the polyester from the polyvinyl chloride by isolating the residue and the foam product.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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