PROCESS AND PLANT FOR REMOVING DYES FROM WASTE TEXTILES

Abstract

In a process for removing dyes from a waste textile material, including at least 50% by weight of polyester fibers, a batch of said textile material in an extraction chamber is extracted with a solvent that is circulated through the textile and the extraction chamber; said solution comprising solvent and extracted material is used as a solvent to extract dye from another batch of textile material, and in that said steps of extraction are repeated, until the amount of extracted material in said solution comprising solvent and extracted material reach a concentration whereby further dye extraction is impaired.

Claims

1. A process for removing dyes from a textile material wherein said textile material includes at least 50% by weight, of polyester that is dyed, said process comprising the following steps: a) providing a batch of said textile material in an extraction chamber; b) extracting said batch of said textile material with a solvent to provide a solution comprising solvent and extracted material, said extracted material including at least a dye, wherein said textile material is kept in a still condition and said solvent is circulated through said textile material textiles and said extraction chamber; c) removing said solution of solvent and extracted material from said textile material; and d) using said solution comprising solvent and extracted material obtained in said step b) and/or said step c) is used as a solvent to extract dye from another batch of said textile material, and in that repeating said steps b) and c) for a preset number of cycles or until an amount of extracted material in said solution comprising solvent and extracted material reaches a concentration whereby further dye extraction is impaired.

2. The process according to claim 1, wherein at least part of said polyester is dyed with at least one disperse dye or dope-dyed, said textile material is a waste textile material selected from the group consisting of fibers, fiber tufts, filaments, yarns, fabrics, clippings of fabrics, garments, clippings of garments and mixtures thereof, and said textile material is pressed in said extraction chamber or in a basket housed in said extraction chamber.

3. The process according to claim 1, wherein said step c) includes a step of separating said solution comprising solvent and extracted material from said textile by centrifuging, wherein said step c) is carried out in a centrifuge, and said extraction chamber is configured to operate as centrifuge.

4. The process according to claim 3, wherein, after said step c), solvent is fed to the centrifugated textile material present in said centrifuge and a washing step of said textile material is carried out in said centrifuge to remove dyes from said centrifugated textile material.

5. The process according to claim 1, wherein said extraction chamber is a first extraction chamber, and wherein said textile material, after a first said extraction step b), is fed from said first extraction chamber to a first centrifuge for a first removal step c), from said first centrifuge to a second extraction chamber for a second extraction step b) and from said second extraction chamber to a second centrifuge for a second removal step c), whereby said first and second extraction steps b) and removal steps c) are carried out in two different extraction chambers and two different centrifuges, respectively.

6. The process according to claim 5, wherein the solvent removed from said second extraction chamber and/or said second centrifuge, is fed to said first extraction chamber.

7. The process according to claim 1, wherein said steps b) and c) are repeated more than twice in more than two extraction chambers and centrifuges, and wherein the solvent removed from any said extraction chamber except a first said extraction chamber, is fed to a previous extraction chamber such that said removed solvent used in said step b) is in the form of a solution comprising solvent and an extracted material, said extracted material including at least a dye.

8. The process according to claim 1, wherein said solvent comprises DMF or DMAC or a mixture of DMF or DMAC with alkali water, or mixtures thereof and the temperature of said solvent or said solution comprising solvent and extracted material in said extraction chamber, is in the range of 80 C. to 140 C.

9. The process according to claim 1, wherein a bath ratio textile/solvent (kg/liters) is in a range of 1/3 to 1/20.

10. The process according to claim 1, wherein said step c) is carried out in a centrifuge at a g-force in the range of from 250 to 5000 for a time in the range of from 0.5 to 10 minutes.

11. The process according to claim 1, wherein said textile material comprises polyester fibers and further comprises at least a polyurethane material; said textile material comprising at least 90% by weight of said polyester fibers and at most 10% by weight of polyurethane fibers, wherein at least part of said polyester fibers is dyed with at least one disperse dye, said solvent is DMF, and the temperature of said solvent or said solution comprising solvent and extracted material in said extraction chamber is in the range of from 85 C. to 105 C.

12. The process according to claim 1, wherein said textile material comprises polyester fibers and further comprises at least cellulosic cotton fibers, said textile material comprising at least 50%, by weight of said polyester fibers and at most 50%, by weight of said cellulosic cotton fibers, wherein at least part of said polyester fibers is dyed with at least one disperse dye and wherein at least part of said cellulosic cotton fibers is dyed with at least a dye selected from the group consisting of vat dyes, reactive dyes, pigments, direct dyes and sulfur dyes, wherein said solvent is a mixture of DMF and water comprising at least one base, and wherein the temperature of said solvent or said solution comprising solvent and extracted material in said extraction chamber and optionally in said washing step is in a range of 85 C. to 110 C.

13. The process according to claim 1, wherein said textile material comprises polyester fibers and further comprises at least elastane and cotton fibers, wherein said textile material comprises at least 50% by weight of said polyester fibers and at most 50% by weight of said cotton fibers and elastane fibers, wherein at least part of said polyester fibers is dyed with at least one disperse dye and wherein at least part of said cotton fibers is dyed with at least a dye selected from the group consisting of vat dyes, reactive dyes, pigments, direct dyes and sulfur dyes, wherein said solvent is a mixture of DMF and water comprising a base and at least one reducing agent, wherein the temperature of said solvent or said solution comprising solvent and extracted material in said extraction chamber and is in a range of 95 C. to 105 C.

14. The process process according to claim 1, wherein said solution obtained in said step b) and/or in said step c) is used as the solvent to extract dye from another batch of textile material, and in that said steps b) and c) are repeated using said solution as said solvent up to 40 times.

15. An apparatus for removing dyes from a textile material in a process according to claim 1, said apparatus comprising: at least one said extraction chamber (2) configured to treat said textile material with said solvent, a pump (P) adapted to circulate said solvent through said extraction chamber (2) and said waste textile material, at least a centrifuge (3) for separating said solution comprising solvent and extracted material from said textile material, at least one fresh solvent storage tank (6), and at least one distillation device (5), wherein said at least one fresh solvent storage tank (6) is configured to feed said fresh solvent to said extraction chamber (2), and configured to receive said solvent from said distillation device (5), and said distillation device (5) is configured to receive said solution comprising solvent and extracted material from said extraction chamber (2) and/or from said centrifuge (3), to separate said extracted material from said solvent.

16. The apparatus according to claim 15, wherein said apparatus comprises: a plurality of said extraction chambers (2a-2d) and a plurality of said centrifuges (3a-3d), wherein said extraction chambers (2a-2d) and said centrifuges (3a-3d) are arranged in a series; and means for feeding said textile material along said series of extraction chambers (2a-2d) and centrifuges (3a-3d) to provide a flow of said textile material textiles, wherein at least one said centrifuge (3) is connected, directly or indirectly, with one said extraction chamber (2) upstream with respect to the flow of said textile material and is connected to a further said extraction chamber (2) downstream with respect to said flow of said textile material.

17. The apparatus according to claim 15, wherein each said extraction chamber is connected to a previous extraction chamber with solvent feeding means configured to feed said solution comprising solvent and extracted material exiting from each extraction chamber to said previous extraction chamber and wherein only a last extraction chamber of said extraction chambers of said series is connected to said fresh solvent storage tank, said fresh solvent storage tank configured to feed said solvent to said last extraction chamber only.

18. The apparatus according to claim 15, further comprising at least one storage tank (7a-7d), configured to receive said textile material from said extraction chamber (2) and to feed said textile material to said centrifuge (3), wherein said extraction chamber (2) is configured to operate as said centrifuge.

19. An apparatus for removing dyes from a textile, comprising: at least one extraction chamber (2) configured to treat a waste textile material with a solvent, a pump (P) for circulating said solvent through said extraction chamber (2) and said waste textile material, at least a centrifuge (3) for separating a solution comprising said solvent and extracted material from said textile material, and at least one fresh solvent storage tank (6) and at least one distillation device (5), wherein said at least one fresh solvent storage tank (6) is configured to feed fresh solvent to said at least one extraction chamber (2) and configured to receive said solvent from said at least one distillation device (5), wherein said at least one distillation device (5) is configured to receive said solution comprising said solvent and said extracted material from said extraction chamber (2) and/or said centrifuge (3), to separate said extracted material from said solvent; said apparatus further comprising at least one storage tank (7a-7d), configured to receive said waste textile material from said extraction chamber (2) and to feed said textile material to said centrifuge (3).

20. The apparatus according to claim 19, wherein said extraction chamber (2) is configured to operate as said centrifuge (3).

Description

[0095] Further aspects and advantages in accordance with the present disclosure will be discussed more in detail with reference to the enclosed drawings, given by way of non-limiting example, wherein:

[0096] FIG. 1 shows a schematic representation of an embodiment of the process and apparatus of the invention including one extraction chamber and one centrifuge;

[0097] FIG. 2 shows a schematic representation of an embodiment of the process and apparatus of the invention including two extraction chambers and two centrifuges;

[0098] FIG. 3 shows a schematic representation of an embodiment of the process including four extraction chambers and four centrifuges;

[0099] FIG. 4 is a photograph showing the aspect of textile material (small pieces of polyester fabric) after size reduction step, before extraction step;

[0100] FIG. 5 is a photograph showing the aspect of textile material (small pieces of polyester fabric) at the end of the process.

[0101] In the attached drawings, continuous arrows schematically represent the flow of the textile material while dashed arrows schematically represents the flow of the solvent and/or the solution comprising solvent and the extracted material.

[0102] With reference to the exemplary embodiment of FIG. 1, the waste textile material is collected and pre-treated to reduce the size of the textile in a textile size reduction device 1. For example, the textile size reduction device 1 can be a cutter machine, suitable for cutting fabrics and garments into pieces, i.e., clippings, or a machine suitable for converting fabrics and/or garments into fibers. The size of the pieces of fabric have been previously disclosed in the description: a sample of light blue polyester fabric reduced to pieces having a size that is at least 90% in the range 2.0 mm to 2.5 mm is shown in FIG. 4.

[0103] The textile material, after size-reduction pre-treatment, is moved to an extraction chamber 2.

[0104] In the extraction chamber 2, the textile material is extracted (treated) with a solvent, to provide a solution comprising solvent and extracted material, said extracted material including at least a dye. During said step b), said solvent, or said solution comprising solvent and extracted material, is circulated through said textile material entering said extraction chamber 2 and exiting said extraction chamber 2. The extraction chamber 2 is kept in a static, i.e., still, condition during step b). The textile materials, e.g. fabrics or garments or fibers, housed within the extraction chamber 2, are, too, in a still, i.e. static, condition, apart for possible movement imparted by the flow of the solvent that is circulated, e.g. with a pump P, through the static extraction chamber 2 and through the textiles. Preferably the textiles are kept in a static condition. In a preferred embodiments the textile material is in a compressed condition; in this embodiment the textile are preferably in the form of fibers or fiber tufts as obtainable by a textile opening process via tearing machines such as those commercialized by Laroche, Dell'Orco & Villani (IT) and Trtzschler (DE).

[0105] According to embodiments, extraction step b) has a duration of from 2 minutes to 20 minutes, preferably from 5 min to 15 min, more preferably from 7.5 min to 12.5 min., most preferably 10 min.

[0106] According to embodiments, the temperature of the solvent (or the solution comprising solvent and extracted material) in the extraction chamber 2 is in the range of from 80 C. to 140 C., preferably from 82 C. to 135 C. Maximum temperature may be about 110 C. when the polyester is not dope dyed but is dyed e.g. with disperse dyes.

[0107] Advantageously, the conditions of the extraction step b) can be adjusted according to the composition of the textile material to be treated.

[0108] For example, when the textile material is in the form of 100% PET fabrics and/or clippings, dyed with at least one disperse dye, the solvent is preferably DMF, and the temperature of said solvent in said extraction chamber 2 may be in the range of from 85 C. to 105 C., preferably about 100 C. For example, when the textile material is in the form of 100% PET fibers dyed with at least one disperse dye, the solvent is preferably DMF, and the temperature of said solvent in said extraction chamber 2 may be in the range of from 80 C. to 110 C., preferably from 85 C. to 105 C. For example, when the textile material comprises at least 90% by weight of polyester fibers, dyed with at least one disperse dye, and at most 10% by weight of elastane fibers, the solvent is preferably DMF, and the temperature of said solvent in said extraction chamber 2 may be in the range of from 85 C. to 105 C., and preferably is about 95 C. For example, when the textile material comprises at least 70% by weight of polyester fibers and at most 30%, by weight of cotton fibers or of a mixture of cotton fibers and elastane, and the polyester fibers are dyed with at least one disperse dye, and the cotton fibers are dyed with at least a dye selected from vat dyes, reactive dyes, pigments, direct dyes and sulfur dyes, the solvent is preferably a mixture of DMF and water comprising a reducing agent and a base, and the temperature of said solvent in said extraction chamber 2, is in the range of from 95 C. to 105 C., preferably about 100 C.

[0109] After step b) a solution comprising solvent and extracted material (i.e., at least one extracted dye and, optionally, extracted polyurethane materials such as elastane) is obtained, together with treated textiles.

[0110] According to the invention, solution comprising solvent and extracted material can be recirculated during step b), by exiting and entering the extraction chamber 2, while keeping both the textiles and the extraction chamber 2 in a static (i.e., still) condition.

[0111] According to embodiments, at the end of step b), the textiles are moved to a centrifuge 3 for removal of the residual solution comprising solvent and extracted material in the textiles, according to step c). In embodiments, centrifuging can be carried out in the extraction chamber. For example, when the extraction chamber is a washing machine or a solvent cleaning machine, the extraction chamber may perform centrifugation, and optionally washing with solvent, washing with water and drying. In embodiments, extraction, centrifugation, washing, drying can be performed in one machine, e.g., in a solvent cleaning machine; the same machine can further include a distillation unit.

[0112] In embodiments, the solvent that has not been picked up by the textiles can be removed from the extraction chamber 2 and fed to a solvent storage tank 9. The solvent storage tank 9 is further configured to receive the solvent removed from at least the centrifuge 3 and, optionally, from the drying device 4. The solvent in the solvent storage tank 9 is generally a solution comprising solvent and extracted material. The solvent (or the solution comprising solvent and extracted material) can be fed from the solvent storage tank 9 to the extraction chamber 2.

[0113] According to embodiments, centrifugation is carried out at g-force in the range of from g-force from 250 to 5000, preferably from 800 and 2000, more preferably from 900 to 1300, e.g., 1200, for a time in the range of from 0.5 to 10 minutes, preferably from 1 to 5 minutes. In embodiments, after centrifugation, the solution of solvent and extracted material is moved back to the extraction chamber 2 for treating another batch of textile material, e.g., a new batch of textile material.

[0114] In embodiments, after centrifugation, the textile material may be washed within the centrifuge 3. The washing can be performed, for example, using fresh solvent or fresh mixture of solvent, water, a reducing agent and a base, according to the material to be washed. The fresh solvent or fresh mixture of solvent, water, a reducing agent and a base, are fed to the centrifuge 3 by the fresh solvent tank 6. The temperature of said clean solvent in said centrifuge during the solvent washing step is in the range of 80 C. to 110 C., preferably from 85 C. to 105 C. for polyester fibers and is in the range of from 85 C. to 110 C., preferably about 95 C. The washed material is centrifuged to remove the solvent used for washing. The solvent or the mixture of solvent, water, a reducing agent and a base is recovered and preferably fed to the extraction chamber 2 for treating another batch of textile material.

[0115] According to FIG. 1, after centrifugation, the textile material is dried in a drying device 4.

[0116] When the extracted material in the solution comprising solvent and an extracted material reach a concentration whereby further dye extraction is impaired, the solution comprising solvent and extracted material is fed, from said extraction chamber 2 and/or from said centrifuge 3, to a distillation device 5, whereby said solvent is separated from said extracted material. Distilled solvent is, then, moved to a fresh tank solvent 6 for storage. When required, fresh solvent can be fed from the fresh solvent tank 6 to at least the extraction chamber 2, for example, to adjust the bath ratio textile: solvent. As above mentioned, fresh solvent can be fed from the fresh solvent tank 6 to the centrifuge 3 to perform washing of the textiles.

[0117] In an embodiment said textile material is selected from polyester fibers, fabrics consisting of polyester fibers, fabric clippings consisting of polyester fibers, polyester fibers ground into polyester powder, wherein at least part of said polyester fibers is dyed with at least one disperse dye, wherein said solvent is DMF, wherein the temperature of said solvent or said solution comprising solvent and extracted material in said extraction chamber is in the range of 80 C. to 110 C., preferably from 85 C. to 105 C. for polyester fibers and is in the range of from 85 C. to 110 C., preferably about 95 C. for said fabrics, fabric clippings and polyester powder.

[0118] In an embodiment, said textile material comprises at least 90% by weight of polyester fibers and at most 10% by weight of elastane fibers, wherein at least part of said polyester fibers is dyed with at least one disperse dye, wherein said solvent is DMF, wherein the temperature of said solvent or said solution comprising solvent and extracted material in said extraction chamber and preferably in the step of washing in the centrifuge after a first centrifugation is in the range of from 85 C. to 105 C., preferably about 95 C.

[0119] In an embodiment said textile material comprises at least 50%, preferably 70%, by weight of polyester fibers and at most 50%, preferably 30%, by weight of cotton fibers, wherein at least part of said polyester fibers is dyed with at least one disperse dye and wherein at least part of said cotton fibers is dyed with at least a dye selected from vat dyes, reactive dyes, pigments, direct dyes and sulfur dyes, wherein said solvent is a mixture of DMF and water comprising at least one base and optionally at least one reducing agent, wherein the temperature of said solvent or said solution comprising solvent and extracted material in said extraction chamber and preferably in the step of washing in the centrifuge after a first centrifugation is in the range of from 85 C. to 110 C., preferably about 95 C.

[0120] FIG. 2 shows a schematic representation of an embodiment of the process and apparatus of the invention including two extraction chambers (2a and 2b) and two centrifuges.

[0121] With reference to the exemplary embodiment of FIG. 2, the waste textile material is collected and pre-treated to reduce the size of the textile in a textile size reduction device 1. The textile material, after size-reduction pre-treatment, is moved to a first extraction chamber 2a. In the extraction chamber 2a, the textile material is extracted (treated) with a solvent, to provide a solution comprising solvent and extracted material, said extracted material including at least a dye. Preferably, when the apparatus incudes more than one extraction chambers, the solvent used in the first extraction chamber is the solution comprising solvent and extracted material obtained in the second extraction chamber after the second extraction step b) carried out on the previous batch of textiles that have been treated. The solution comprising solvent and extracted material is recirculated during step b), by exiting and entering the first extraction chamber 2a, while keeping both the textiles and the extraction chamber 2 in a static (i.e., still) condition.

[0122] According to embodiments, at the end of step b), the textiles are moved from the first extraction chamber 2a to a first centrifuge 3a for removal of the residual solution comprising solvent and extracted material in the textiles, according to step c). According to embodiments, centrifugation is carried out at a g-force from 250 to 5000 preferably from 800 and 2000, more preferably from 900 to 1300, for a time in the range of from 0.5 to 10 minutes, preferably from 1 to 5 minutes. In embodiments, after centrifugation, the solution of solvent and extracted material is moved back to the extraction chamber 2 for treating another batch of textile material.

[0123] The textile material, after centrifugation, is moved from the first centrifuge 3a to a second extraction chamber 2b. In the second extraction chamber 2b, the textile material is further extracted (treated) with a solvent, to provide a solution comprising solvent and extracted material, said extracted material including at least a dye. Preferably, when the apparatus incudes more than one extraction chambers, the solvent used in the second extraction chamber may be fresh solvent. The textile material is kept in a static condition within extraction chamber 2b, during the entire extracting step.

[0124] In analogy to the embodiment of FIG. 1, with reference to FIG. 2, in embodiments, the solvent that has not been picked up by the textiles can be removed from the extraction chambers 2a and 2b and fed to at least one solvent storage tank (not shown in the figures). The at least one solvent storage tank is further configured to receive the solvent removed from at least the centrifuges 3a and 3b and, optionally, from the drying device 4. The solvent in the solvent storage tank is generally a solution comprising solvent and extracted material. The solvent (or the solution comprising solvent and extracted material) can be fed from the at least one solvent storage tank to the extraction chambers 2a and 2b.

[0125] In embodiments, in multiple extraction process, all extraction chambers will be fed with fresh solvent in the beginning of the process (i.e., for treating the first batch of waste textiles) and the solvent will be re-used in the same extractors till reaching the saturation point, i.e., a condition wherein the extracted material in the solvent reach a concentration whereby further dye extraction is impaired, e.g., after extraction of at least 20 batches, preferably at least 30, more preferable at least 40, for example 50. Starting from the second batch of waste textile to be treated, fresh solvent is fed only to the last extraction chamber.

[0126] Similarly to extraction chamber 2a, the obtained solution comprising solvent and extracted material is recirculated during step b), by exiting and entering the second extraction chamber 2b, while keeping both the textiles and the extraction chamber 2b in a static (i.e., still) condition.

[0127] At the end of step b), the textiles are moved from the second extraction chamber 2b to a second centrifuge 3b for removal of the residual solution comprising solvent and extracted material in the textiles, according to step c). In embodiments, after centrifugation, the solution of solvent and extracted material is moved back to the second extraction chamber 2b for treating another batch of textile material.

[0128] Preferably, the solution comprising solvent and extracted material obtained after one or more extraction steps in the second extraction chamber 2b is fed to the first extraction chamber 2a to extract a different batch of textiles.

[0129] In embodiments, after centrifugation in the second centrifuge 2b, the textile material may be washed within the second centrifuge 3b. The washed material is centrifuged to remove the solvent used for washing. The solvent or the mixture of solvent, water and a reducing agent and a base is recovered and preferably moved to the second extraction chamber 2b for treating another batch of textile material.

[0130] According to FIG. 2, after the second centrifugation in the second centrifuge 3b, the textile material is dried in a drying device 4.

[0131] When the extracted material in the solution comprising solvent and an extracted material reach a concentration whereby the solvent is saturated and further dye extraction is impaired, the solution comprising solvent and extracted material is fed to a distillation device 5, whereby said solvent is separated from said extracted material. Distilled solvent is, then, moved to a fresh tank solvent 6 for storage. When required, fresh solvent can be fed from the fresh solvent tank 6 to at least the second extraction chamber 2b, for example, to adjust the bath ratio textile: solvent. As above mentioned, fresh solvent can be fed from the fresh solvent tank 6 to the second centrifuge 3b to perform washing of the textiles. Optionally, fresh solvent can be fed from the fresh solvent tank 6 to the first centrifuge 3a, to perform washing of the textile.

[0132] FIG. 3 shows a schematic representation of an embodiment of the process including a plurality (four) extraction chambers and a plurality (four) of centrifuges.

[0133] In the embodiment of FIG. 3, a plurality of storage tanks, particularly a plurality of first storage tanks 7a, 7b, 7c, 7d and a plurality of second storage tanks 8a, 8b, 8c, 8d are shown. One first storage tank 7a, 7b, 7c, 7d is provided after each extraction chamber 2a, 2b, 2c, 2d and one second storage tank 8a, 8b, 8c, 8d is provided after each centrifuge 3a, 3b, 3c, 3d.

[0134] According to embodiments, the textile material obtained in step b), i.e., the textile material after extraction with solvent, can be moved from extraction chambers 2a, 2b, 2c, 2d to first storage tanks 7a, 7b, 7c, 7d, for example, when the centrifuges 3a, 3b, 3c, 3d are not able to hold the entire amount of textile material treated in the reaction chambers 2a, 2b, 2c, 2d, the textile material obtained in step b) can be moved from the extraction chambers 2a, 2b, 2c, 2d to first storage tanks 7a, 7b, 7c, 7d so that a further batch of textile material can be extracted in the extraction chambers 2a, 2b, 2c, 2d, while the centrifugation of the textile material obtained in step b) is completed.

[0135] In the embodiment of FIG. 3, the textile material exiting from the centrifuges 3a, 3b, 3c 3d is moved to second storage tanks 8a, 8b, 8c, 8d. The material in the first three second storage thanks 8a, 8b, 8c in then fed to the subsequent extraction chamber (i.e., extraction chamber 2b, 2c, 2d) for further extraction. The textile material in the last second storage tank 8d is free, or substantially free, of dye and possible polyurethane and is ready to be dried.

[0136] The solution comprising solvent and extracted material obtained in each extraction chamber is recirculated during step b), by exiting and entering the same extraction chamber, while keeping both the textiles and the extraction chamber in a static (i.e., still) condition.

[0137] In embodiments, after centrifugation, the solution of solvent and extracted material is moved back to the previous extraction chamber for treating another batch of textile material. For example, with reference to FIG. 3, the solution of solvent and extracted material obtained after centrifugation in centrifuge 3a is moved back to extraction chamber 2a, the solution of solvent and extracted material obtained after centrifugation in centrifuge 3b is moved back to extraction chamber 2b, the solution of solvent and extracted material obtained after centrifugation in centrifuge 3c is moved back to extraction chamber 2c and the solution of solvent and extracted material obtained after centrifugation in centrifuge 3d is moved back to extraction chamber 2d.

[0138] According to the embodiment of FIG. 3, the solvent used in the last extraction chamber 2d may be fresh solvent. After the extraction, a solution including solvent and extracted material is obtained. The solution including solvent and extracted material obtained in the last (fourth) extraction chamber 2d may be fed to the previous (third) extraction chamber 2c, for the third extraction step of the subsequent batch of textiles, particularly, after that the solvent, i.e., solution comprising solvent and extracted material, used in first extraction tank 2a reached a concentration of extracted material whereby further dye extraction is impaired, and the solution comprising solvent and extracted material is moved from the first extraction chamber 2a to the distillation device. The solution including solvent and extracted material obtained in the third extraction chamber 2c may be fed to the previous (second) extraction chamber 2b, for the second extraction step of the subsequent batch of textiles. The solution including solvent and extracted material obtained in the second extraction chamber 2b may be fed to the previous (first) extraction chamber 2a, for the first extraction step of the subsequent batch of textiles. Advantageously, the amount of dye in the textile is progressively reduced from the first extraction chamber 2a to the last extraction chamber 2d, while the concentration of the extracted material, particularly dye, in the solvent (i.e., the solution comprising solvent and extracted material) used in the extraction steps decreases the first extraction chamber 2a to the last extraction chamber 2d. In other words, the solution including solvent and extracted material obtained in the last (fourth) extraction chamber 2d is sent to the third extraction chamber 2c, for the third extraction step of the subsequent batch of textiles, after that the solvent used in first extraction chamber 2a is sent to distillation device, and the solvent used in the second extraction chamber 2b is sent to the first extraction chamber 2a, and the solvent used in the third extraction chamber 2c is sent to the second extraction chamber 2b.

[0139] FIG. 4 and FIG. 5 visually show the reduction in dye content from the initial polyester material in reduced size (FIG. 4) to the same material at the end of the process (FIG. 5).

[0140] The invention will be further illustrated by reference to the following non limiting examples.

EXAMPLE 1

[0141] 1.5 kg of waste textile fabrics (90 % PET (dispersed dyed)10 % cotton (reactive dyed)) were put into the extraction chamber. 15 L of solvent (DMF) were added to the extraction chamber and were heated to 90-95 degC. After 10 min. extraction with circulation of solvent, textiles were sent directly to the centrifuge and solvent was removed at 1200 g-force for 2-3 min. Afterwards textiles were sent to second extractor and 15 L of DMF-water were poured in presence of reducing agent (Na.sub.2S.sub.2O.sub.4) and base (NaOH) to remove reactive dyes at 90-95 degC for 10 min. Drying process at 80-90 degC were conducted after second centrifuge process. The solvents are re-collected and re-used.

EXAMPLE 2

[0142] 1.5 kg of waste textiles (90 % PET (dispersed dyed)-10 % cotton (reactive dyed)) were put into the extractor. 15 L of DMF-water (in presence of reducing agent and base) were added to the extraction chamber and were heated at 90-95 degC. After 10 min. extraction with circulation of solvent, textiles were sent directly to the centrifuge and solvent was removed at 1200 g-force for 2-3 min. Afterwards textiles were sent to second extraction chamber and 15 L of DMF were poured into it to remove remaining dyes at 90-95 degC for 10 min. Drying process at 80-90 degC were conducted after second centrifuge process. The solvents are re-collected and re-used.

[0143] The claimed process and apparatus thus allows to remove dyes from waste textiles, particularly disperse dyes from polyester fibers and vat dyes, reactive dyes, pigments, direct dyes and sulfur dyes from cotton fibers. The resulting textiles may then be recycled in a way known per se.