Method for the utilization of constituents from blended textile wastes

Patent metadata

Field	Value
Publication number	US-12528232-B2
Application number	US-202017784520-A
Country	US
Kind code	B2
Filing date	Dec 3, 2020
Priority date	Dec 13, 2019
Publication date	Jan 20, 2026
Grant date	Jan 20, 2026

Abstract

The invention relates to a method for the treatment and utilization of waste liquor containing at least polyester degradation products and originating from an alkaline pulping process for the extraction of cellulose raw material from blended textile waste which contains at least a cellulose component and a polyester component. In order to make the method environmentally friendlier and more resource-efficient, it is proposed that the method comprises the following steps: the evaporation of water from the waste liquor in order to precipitate the polyester degradation product from the waste liquor and to obtain a two-phase mixture having an aqueous phase and a solid phase including the polyester degradation product, b) the separation of the solid phase from the liquid phase, and c) the thermal/energetic utilization of the solid phase.

First claim

The invention claimed is:

1 . A method for the treatment and utilization of waste liquor, the waste liquor being aqueous and containing polyester degradation products, the method comprising the following steps:
a) obtaining the waste liquor by extracting a cellulose raw material from a blended textile waste, the blended textile waste comprising a cellulose component and a polyester component, wherein the polyester component undergoes an alkaline hydrolysis to form the polyester degradation products and wherein the cellulose component is separated from the polyester degradation products to obtain the cellulose raw material, b) evaporating water from the waste liquor to precipitate the polyester degradation products from the waste liquor and to obtain a two-phase mixture having an aqueous phase and a solid phase, the two-phase mixture including the polyester degradation products, c) separating the solid phase from the aqueous phase, and d) utilizing the solid phase.

2 . The method as claimed in claim 1 , wherein, following step c), the aqueous phase is fed to a waste water treatment process or put to another use in the pulp production process.

3 . The method as claimed in claim 1 , wherein the solid phase is utilized thermally in step d) for the generation of energy in the form of steam and/or electric power.

4 . The method as claimed in claim 3 , wherein, in step d), the solid phase is fed to a boiler provided with slag tap firing.

5 . The method as claimed in claim 1 , wherein, in step b), water is evaporated from the waste liquor until the waste liquor has a solid content between 20 and 40 wt %.

6 . The method as claimed in claim 1 , wherein the waste liquor includes NaOH and the polyester degradation products comprise a sodium salt of terephthalic acid.

7 . The method as claimed in claim 1 , wherein step b) is repeated twice or more.

8 . The method as claimed in claim 7 , wherein, in step c), a mechanical separator is used for separating the solid and the liquid phase.

9 . The method as claimed in claim 7 , wherein the waste liquor contains disodium terephthalate prior to step b) and wherein step b) is repeated until the two phase mixture does not contain disodium terephthalate.

10 . The method as claimed in claim 1 , wherein step b) is repeated at least twice and up to ten times.

11 . The method as claimed in claim 1 , wherein step b) is repeated at least twice and up to six times.

Assignees

• Chemiefaser Lenzing Ag

Inventors

• Herchl Richard
• Klaus-Nietrost Christoph
• Theis Sabrina
• Weilach Christian

Classifications

• D21C11/0007

  Recovery of by-products, i.e. compounds other than those necessary for pulping, for multiple uses or not otherwise provided for (volatile compounds obtained by decomposition of spent liquors in order to regenerate them D21C11/125; compounds obtained by fractionating the liquors in order to regenerate them D21C11/0042) · CPC title

• D21C5/00

  Other processes for obtaining cellulose, e.g. cooking cotton linters (obtaining fibres for spinning D01C); {Processes characterised by the choice of cellulose-containing starting materials} · CPC title

• D21C3/02

  with inorganic bases or alkaline reacting compounds, e.g. sulfate processes · CPC title

• B29B2017/0296

  Dissolving the materials in aqueous alkaline solutions, e.g. NaOH or KOH · CPC title

• B29K2001/00

  Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material · CPC title