Classifying – separating – and assorting solids – Precedent preparation of items or materials to facilitate... – Sorting special items or sorting by methods and apparatus...
Patent
1983-08-16
1986-03-25
Nozick, Bernard
Classifying, separating, and assorting solids
Precedent preparation of items or materials to facilitate...
Sorting special items or sorting by methods and apparatus...
209172, B03B 528
Patent
active
045781842
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a process for non-destructive separation of mixtures containing scrap plastics material and non-plastics materials, such as metal and glass, by sink/float separation of a finely divided mixture of materials in a liquid separating medium.
In recent years upgrading of plastics materials and metal and glass contained in various types of scrap has become ever more important, because of the increasing prices of raw materials which have rendered reuse more attractive economically, and because of the more stringent environmental regulations which have made reuse a requirement or at any rate a wish on the part of the authorities.
The object of the present invention is to provide a versatile and flexible separating process which is non-destructive and thus enables reclamation of both the constituent plastics materials, and the constituent non-plastics materials, such as metal and glass in an undamaged state, so that they are readily useful as raw materials in the common methods of processing the materials.
The invention will be explained in the following with reference to a mixture of materials in a category which is particularly difficult to separate, viz. wire and cable scrap which contains plastics materials as well as metals, but the invention is equally applicable to mixtures in which part of the material originates from other scrap processing procedures, and the non-plastics materials may e.g. also contain glass from the production of optical fibres or of another origin.
The greatest advantages of the invention, however, are within the upgrading of scrap cable since the previously used methods have either resulted in an insufficient separation of metals and plastics materials or have focussed on reclamation of one type of materials while destroying or decomposing the other one.
Examples of the known cable or wire scrap processing types are: which do not require any noticeable pre-treatment of the material, offers a plurality of possibilities based on gravitation separation: separation", which is widely used optionally followed by mechanical separation. that, for reasons of economy, they are used for the processing of strong cables with a high metal content and big wire dimensions. Further, the plastics fractions have to be granulated and optionally separated after processing before they can be reused.
Combustion or pyrolysis of the plastics material (method B) does not permit of reuse and will not be described in detail.
Swelling of the plastics materials (method H) is e.g. described in the U.S. Pat. No. 3,877,474 (Urssing et al.), in which, with a view to reclamation of the metallic conductor in bales of cable or wire scrap, the insulation is swollen and softened, with simultaneous mechanical treatment, with a chlorinated hydrocarbon, preferably methylene chloride, but also e.g. carbon tetrachloride, ethylene dichloride, propylene dichloride, chlorobenzene, 1,1,1-trichloroethane, perchloroethylene, trichloroethylene or chloroform. The residence time is relatively long; it is stated in the specification that the insulation can be reused, but this has not been rendered probable.
Methods of recovering PVC from PVC/metal mixtures based on dissolution of PVC are described in the U.S. Pat. No. 3,666,691 (Spiller) and No. 3,836,486 (Hafner). These methods are not expedient i.a. owing to the large amount of solvents necessary to dissolve the plastics material, and owing to the different dissolubility of the various plastics, cf. the abovementioned U.S. Pat. No. 3,877,474.
In methods C, D, E, and F, metal and plastics, in particular from an insulation, are separated after granulation. The advantage of effecting the granulation, besides involving significant economic benefits, is that the materials are present in a form which, in principle, makes them easy to separate, and that the insulation material lends itself to reuse, in terms of size and form. Two considerable drawbacks of method C are that there is no separation of the various constituent plastics components of the insulation m
REFERENCES:
patent: 3122498 (1964-02-01), Werner
patent: 3335966 (1967-08-01), Haverman
patent: 3666691 (1972-05-01), Spiller
patent: 3749322 (1973-07-01), Reynolds
patent: 3836486 (1974-09-01), Hafner
patent: 3877474 (1975-04-01), Urssing et al.
patent: 3992288 (1976-11-01), Kling
patent: 4059604 (1977-11-01), Kresse
patent: 4252639 (1981-02-01), Smith et al.
patent: 4332677 (1982-06-01), Budzich
Roe & Tueter-Application of Heavy-Liquid Processes to Mineral Benefaction-Soc. of Mech. Engrs., Jun. 63, pp. 141-146.
Aktieselskabet Nordiske Kabel-og Traadfabriker
Nozick Bernard
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