Method for the preparation of highly purified recycled nylon

摘要

The present invention relates to the recovery of nylon from co-mingled materials (e.g., carpet) with reduced or eliminated ash (e.g., calcium carbonate) contamination.

主权项

1. A method of reducing and/or eliminating ash contamination in nylon separated from co-mingled materials, comprising the following ordered steps:
a) separating a co-mingled material comprising nylon from free calcium carbonate, yielding a co-mingled material comprising nylon and surface-exposed calcium carbonate; b) contacting the co-mingled material comprising nylon and surface-exposed calcium carbonate with an aqueous dilute acid solution thereby forming a water soluble calcium salt, wherein the surface-exposed calcium carbonate dissolves in the aqueous dilute acid solution and the nylon is insoluble in the aqueous dilute acid solution; and c) separating the aqueous dilute acid solution comprising the solubilized calcium salt from the insoluble nylon and other materials, thereby reducing and/or eliminating ash contamination from the co-mingled nylon, wherein the method does not comprise densitometric separation.