CH694989A5 - Domestic waste treatment procedure consists of grinding and mixing with abrasive material and bonding agent to make building materials - Google Patents

Abstract

Waste treatment procedure consists of sorting the waste to remove any metal, synthetic materials and wood, crushing the sorted material, subjecting it to ultraviolet and/or infrared radiation and mixing it with an abrasive material such as sand or ground demolition debris. Waste treatment procedure consists of sorting the waste to remove any metal, synthetic materials and wood, crushing the sorted material, subjecting it to ultraviolet and/or infrared radiation and mixing it with an abrasive material such as sand or ground demolition debris. The resulting mixture, which contains 30 - 50 per cent of the abrasive material, is divided into powdered and fibrous fractions, each fraction being mixed with a bonding agent containing a synthetic resin and a polymerisation catalyst before being cold-moulded into building materials such as bricks, blocks and slabs that are suitable for use in building and public works.

Description

       

  



   The present invention relates to the treatment of waste such as household waste possibly including demolition debris, to obtain a useful material especially for construction.



   Over the years, the way of life in the so-called developed and industrialized countries has tended to create more and more waste, and in particular, daily life produces a mass of garbage that continues to grow. grow. Also, faced with the problems of storage and disposal of this waste on the one hand, and environmental protection on the other hand, a number of processes have been developed to dispose of this waste in a useful manner.



   Thus, documents FR-A-2 612 175, FR-A-2 612 427 and FR-A-2 622 483 already disclose processes which involve the treatment of household waste to obtain an intermediate product intended to be incorporated. then in a hydraulic setting cement.



   According to these methods, household waste disposed of metal bodies they may contain, are first milled and then treated with a calcium oxide-based mineral material in the free or combined state. The material obtained at the end of this treatment is subjected to a granulation operation under pressure. Finally, the resulting granules or tablets are subjected to a thermal treatment, in particular to reduce the water content and increase their hardness.



   The granules thus obtained are then incorporated in the composition of a cement with the amount of water suitable for setting the cement. They are optionally subjected to a grinding operation to achieve the desired particle size, prior to this mixture.



   Sodium silicate can also be introduced into the mixture.



   Depending on the case, the mixture is either used as such, that is to say as a conventional cement of some sort, or subjected to an additional step of agglomeration or granulation under pressure to lead to granules or pellets.



   It may be noted that the abovementioned methods do not make it possible to manufacture a finished product directly from household waste, but that the treatment carried out, on the contrary, leads to an intermediate product to be incorporated, prior to its use, in a cement to be able to be used for construction.



   Other processes are also known which do not involve a hydraulic setting binder but which still involve treatment in an aqueous medium.



   Document FR-A-2 472 421 describes, for example, a household waste treatment process which consists in subjecting garbage that is free from metal bodies and crushed, to the action of quicklime, of a superactivated lime or a calcium salt such as calcium carbonate in the presence of water.



   The resulting material is then subjected to a heat treatment leading to a product in the form of pieces of variable size and low cohesion.



   These pieces are then transformed into fine powder which is then agglomerated under pressure with a binder. Fillers can be introduced as a fine powder during the agglomeration process, for example to improve the crush strength properties.



   Finally, the product thus formed undergoes a thermal shock.



   This method makes it possible to obtain a product of the type of sand grains, gravel or chippings according to the needs to be satisfied.



     The process according to the document FR-A-2 098 777 consists, for its part, in treating unsorted, but previously dried and crushed detritus. The treatment is carried out with a metal silicate in aqueous solution chosen, for example, from alkali metal silicates. It is either a cold mix or a compression operation, in the presence of a hardener.



   A product capable of absorbing a large quantity of water is advantageously added together with the hardener before mixing.



   The final material is obtained in block form after compacting under high pressure.



   Also known from FR-A-2,337,588, a method for the disposal of household waste that does not include treatment in aqueous medium.



   Indeed, this method consists first of all in a rough grinding of household waste to obtain, for example, fragments having a size of 40 to 100 millimeters.



   Then, after eliminating the metal bodies of the fragments obtained, they are subjected to a drying step and then to a second grinding operation to produce a fine powder having the grain size of a flour.



   This fine powder is then mixed with a binder such as silicate, acrylic, vinyl or polyester resin, pitches or quicklime.



   A plasticizer and a catalyst are also added as well as possibly fillers.



   The mixture thus prepared is introduced into an apparatus to be granulated under pressure and at the end of this operation, cylindrical aggregates whose size is of the order of that of the small gravel are obtained.



   These aggregates are finally dried at a temperature below 200 ° C.



   According to this method, an intermediate product is obtained again and not a finished product that can be used directly as a construction material, since the aggregates formed are intended to be used as replacement for the gravel.



   In general, it can be seen that the various methods proposed for recycling household waste or other detritus are not fully satisfactory insofar as they involve relatively complex steps and / or lead only to intermediaries that can not be considered as finished construction materials directly usable as such.



   The object of the present invention is to provide a method which makes it possible both to dispose of waste in a simple manner and without creating additional pollution, and to prepare directly from such waste a material which can be used in bulk or put into in the form of bricks, blocks, plates, etc. and having particularly advantageous mechanical properties for construction and public works.



   To this end, the subject of the invention is a process for the treatment of waste containing in particular fibrous products, for obtaining a useful material, in particular for the construction or backfill, characterized in that: - waste is eliminated, the metal bodies they can contain, - the waste thus sorted is crushed, - a mixture is formed by adding an abrasive to the sorted and crushed waste, - the said mixture is ground to obtain a material containing pulverulent components and components. fibrous, - said pulverulent components of said fibrous components are separated, - said pulverulent components are removed, - the pulverulent material thus obtained is mixed with a binder containing a synthetic resin and a polymerization catalyst,

     the resulting mixture is fractionated to obtain separate masses and is poured into separate molds; the said masses are cold-molded and their curing is caused by polymerization of the resin.



   According to other features of the invention: - the fibrous components are mixed with a binder containing a synthetic resin and a polymerization catalyst, the resulting mixture is fractionated to obtain separate masses, said masses are cast in separate molds the said masses are cold-molded and their curing is caused by polymerization of the resin.

    a mixture comprising at most 50% of abrasive is formed. - A mixture is formed comprising 30% abrasive. the pulverulent components of the fibrous components are separated by centrifugation of the mixture containing the abrasive. the mixture containing the abrasive is ground and the pulverulent components of the fibrous components are separated simultaneously. - Before crushing, we eliminate the bodies of synthetic material and / or wood contained in the waste. - we treat garbage. prior to the addition of the abrasive, the sorted waste is subjected to the action of infrared and / or ultraviolet rays. - sand is used as abrasive. - Abrasive debris free from metal bodies and crushed is used as abrasive. demolition debris is used which has a particle size similar to that of sand.

   a pulverulent material having a particle size between that of sand and that of talc is obtained.



     at least 60% of pulverulent material is mixed with a binder. 70 to 80% of pulverulent material are mixed with 20 to 30% of binder. at least 60% fibrous components are mixed with a binder. 70 to 80% of fibrous components are mixed with 20 to 30% of binder. - Synthetic concrete is used as binder. at least one dye is introduced during the mixing operation with a binder. at least one insert is placed in the mold prior to pouring a mass. said molds are molded and at least one space is formed which must remain empty of material within the material obtained after hardening of the binder.



   The subject of the invention is also a useful material, in particular for construction or backfill, characterized in that it comprises at least 60% of a material free of metal bodies and obtained after grinding of a mixture of waste containing components. pulverulent and fibrous components with an abrasive then removal of said fibrous components and a binder based on synthetic resin.



   According to other features of the invention: - the material is free of plastic body and / or wood. the material comprises at least 60% of a pulverulent material. the material comprises between 70 and 80% of pulverulent material. - The particle size of the pulverulent material is between that of sand and that of talc. the material comprises at least 60% of fibrous components. the material comprises between 70 and 80% of fibrous components. - the abrasive consists of sand.



     - The abrasive consists of demolition debris free of metal bodies and crushed. - The binder is a synthetic concrete. - The material is fractionated into separate masses and each of said masses is shaped by molding, casting or the like and then cured at room temperature. the material comprises at least one insert. the material comprises at least one empty space of matter. - the material is colored.



   The invention will be better understood with the aid of the description given below by way of illustrative and nonlimiting example.



   The present invention relates to a waste treatment method. Waste means any sort of garbage, garbage, etc., possibly including inert discharges such as demolition debris consisting of rubble, scrap, etc. This waste contains especially fibrous products.



   Whatever their origin, these wastes usually contain metal bodies. Also, the first step of the process consists in eliminating these metal bodies by magnetic means known per se.



   If demolition debris is present, they are also cleared of the metal bodies they contain, such as concrete bars, simultaneously with other waste.



   According to an advantageous embodiment, the bodies of synthetic material and / or wood are also eliminated in order to prevent possible incidents or accidents during the subsequent processing steps. Indeed, the disadvantage of wood for example, is that it is likely to ignite easily when it is en masse with other waste.



   The sorted waste is then subjected to rough crushing.



     Then, the waste thus sorted and crushed is advantageously subjected to the action of infrared rays and / or ultraviolet rays. The action of these rays is used in particular to remove chlorine and other products that could cause pollution in the next step. In particular, it involves removing products that could ignite during grinding and separation operations.



   The material obtained at the end of these steps is mixed with an abrasive. The abrasive consists, for example, of sand.



   In the case where demolition debris is added to the waste, it then acts as an abrasive and the addition of additional material is not necessary. In this case, prior to mixing with the sorted and crushed waste, the demolition debris is crushed to a particle size comparable to that of sand.



   Advantageously, this demolition debris is removed from the wood they contain.



   The amount of abrasive in the mixture is at most 50% and preferably about 30%.



   The next step of the process according to the invention consists in grinding the mixture obtained, comprising on the one hand sorted, crushed waste and possibly after being subjected to the action of infrared and / or ultraviolet rays and on the other hand, the abrasive.



   As a result of this operation, a material containing pulverulent components and fibrous components present in the waste from the outset. These two types of components are then separated so that the pulverulent material alone and the fibrous components alone can be used separately, as described hereinafter.



   According to an advantageous embodiment, grinding operations in the presence of an abrasive and separation of pulverulent components and fibrous components resulting therefrom, are carried out simultaneously by centrifugation of the waste / abrasive mixture, these waste being derived from previous treatments.



   By centrifugation is meant here the application of a rapid rotation to the aforementioned mixture, to obtain the separation of compounds in parallel with grinding resulting from the presence of the abrasive in the moving mixture.



   At the end of this step, there is obtained a powdery material plated on the walls of the centrifuge tank and fibrous components deposited in the bottom of said tank. Of course, the duration of the centrifugation is chosen according to the compounds in the presence and the particle size of the powder that one wishes to achieve. In general, the particle size of the pulverulent material varies between that of talc and that of fine sand.



   The powder is then taken from the walls of the centrifugation vessel and mixed with a synthetic binder in order to obtain a useful material, in particular for the construction or backfill, the fibrous components being able, for their part, to be employed elsewhere.



   The proportion of powder relative to the binder is often influenced by economic factors in parallel with the mechanical characteristics sought for the final product. It is at least 60% and is preferably between 70 and 80%.



   The binder comprises a synthetic resin such as an epoxy resin. In order that the final building material has interesting mechanical characteristics, in particular in terms of its crush resistance, a synthetic concrete is preferably used as a binder.



   By synthetic concrete is meant a composition comprising a binder consisting of a synthetic material (polymer, copolymer, resin, etc.) and inert fillers.



   The binder further contains resin polymerization catalysts and initiators necessary to achieve the final curing phase of the pulverulent material / binder mixture as set forth below.



   In some cases, the binder also comprises polypropylene and liquid rubber or gum-type synthetic material.



   An example of a composition of a material according to the invention is given below: pulverulent material resulting from the grinding-centrifugation stage 60 to 70% 25% epoxy resin polypropylene, rubber or the like 15 to 20% %



   the remainder being additives such as polymerization initiators, catalysts, etc.



   The mixture consists of a simple kneading, manual or automatic, by any known means.



   This mixture is then fractionated into separate masses and each mass is introduced into a mold to give the material the desired shape.



   Various factors may be involved in the choice of the mold and its shape depending on the needs to be met such as cost of manufacture, ease of implementation of the method, etc.



   For this shaping operation, it is possible to use either a mold made of wood, fibers, glass, steel, aluminum or synthetic material such as ABS (acrylonitrile / butadiene / styrene copolymer). Only the surface appearance of the final material obtained differs according to the type of mold chosen.



   The mixture is poured at room temperature into the mold and then compacted by any known means. Of course, before pouring, it is possible to cover the walls of the mold with a release agent, as is well known to those skilled in the art.



   The molding is carried out under normal conditions of temperature and pressure by causing the mass of pulverulent material / binder mixture to harden by polymerization of the resin.



     According to an alternative embodiment of the invention, the fibrous components originating from the grinding-centrifuging separation step in the presence of an abrasive are used in a manner similar to that which has just been described.



   In this case, at least 60% fibrous components are mixed with a binder and preferably between 70 and 80%.



   The person skilled in the art may choose to use a binder of the same type as with the pulverulent material. The splitting and formatting operations are then identical.



   According to the invention, whether it concerns pulverulent components or fibrous components, a finished construction material is obtained from waste, contrary to the methods known to date.



   In addition, the method according to the invention is simple and easy to implement. It is not necessary, in particular, to apply a high pressure or to perform a heat treatment, unlike the known methods.



   The material according to the invention is, for example, in the form of elements such as bricks or plates of greater or lesser thickness. In the latter case, it is possible to obtain thicknesses of less than 5 millimeters.



   One can also juxtapose several elements above and secure them with a binder such as a synthetic concrete as described above.



   The material resulting from the steps described above is a porous material in which one can drive nails or screw screws without prior drilling and which also has a very good resistance to crushing.



   According to the invention, it is also possible to provide additional steps for the introduction of various fillers according to the desired mechanical properties or the completion of finishing treatments.



     Indeed, the material according to the invention obtained as described above can be colored in the mass by introducing one or more coloring agents into the powder / binder mixture or fibrous components / binder, before molding.



   One can also choose to introduce reinforcing fillers in the mixture to improve the mechanical characteristics of the final material obtained.



   The invention also makes it possible to prepare sandwich-type materials. To do this, it indroduits into the mold, prior to casting of the powder material material / binder or fibrous material / binder, an intermediate material for insert. It may be, for example, a metal plate intended to constitute a core for the final product. It may also be a polystyrene plate, a felt, fiberglass or carbon, aramid fibers such as those known under the trade name "KEVLAR" Dupont de Nemours.



   Depending on the use for which the material is intended, it is sometimes interesting to subject it to various finishing treatments.



   This may consist of a simple painting or in other cases, more specific treatments such as a sealing treatment. In this case, the material recovered after demolding is covered with an aqueous solution containing a metal silicate and especially sodium and potassium silicate. This solution then migrates into the material, by capillarity. After crystallization of the metal silicate, the resulting material has become watertight and can float.



   To obtain a material that can float, it is also possible to introduce a flotation insert at the time of the molding operation. It may be, for example, a cube of synthetic material such as polyvinyl chloride (PVC) that is placed in the mold before pouring the mass of pulverulent material / binder mixture or fibrous components / binder.



     Another solution is to mold the mixture, creating, with a suitable mold, one or more spaces to remain empty of material.



   The invention also makes it possible to obtain materials having interesting acoustic properties. Indeed, they absorb the sound and can thus be used in the field of sound insulation.



   Finally, the method according to the invention can advantageously be implemented on a pre-existing waste treatment site.


    

Claims (35)

1. Process for the treatment of waste containing in particular fibrous products, for obtaining a useful material, in particular for the construction or embankment, characterized in that: - waste is eliminated, the metallic bodies that they can contain, the waste thus sorted is crushed, a mixture is formed by adding an abrasive to the sorted and crushed waste, the said mixture is ground to obtain a material containing pulverulent components and fibrous components, and the said pulverulent components are separated from the said components; fibrous components, - said pulverulent components are taken, - the pulverulent material thus obtained is mixed with a binder containing a synthetic resin and a polymerization catalyst,   the resulting mixture is fractionated to obtain separate masses and is poured into separate molds; the said masses are cold-molded and their curing is caused by polymerization of the resin. 2. Method according to claim 1, characterized in that the fibrous components are mixed with a binder containing a synthetic resin and a polymerization catalyst, the resulting mixture is fractionated to obtain separate masses, said masses are cast into separate molds, cold-molded said masses and causes their curing by polymerization of the resin. 3. Method according to claim 1, characterized in that one forms a mixture comprising at most 50% abrasive. 4.  Process according to Claim 3, characterized in that a mixture comprising 30% abrasive is formed. 5. Method according to claim 1, characterized in that the pulverulent components of the fibrous components are separated by centrifugation of the mixture containing the abrasive. 6. Method according to claim 5, characterized in that the mixture containing the abrasive is ground and the pulverulent components of the fibrous components are separated simultaneously. 7. Process according to claim 1, characterized in that prior to crushing, the bodies of synthetic material and / or wood contained in the waste are removed. 8. Method according to claim 1, characterized in that one treats domestic waste. 9.  Process according to Claim 1, characterized in that, prior to the addition of the abrasive, the sorted waste is subjected to the action of infrared and / or ultraviolet rays. 10. Method according to claim 1, characterized in that sand is used as abrasive. 11. Process according to claim 1, characterized in that demolition debris free from metal bodies and crushed is used as abrasive. 12. The method of claim 11, characterized in that one uses demolition debris which have a particle size similar to that of sand. 13. The method of claim 1, characterized in that one obtains a pulverulent material having a particle size between that of sand and that of talc. 14.  Process according to Claim 1, characterized in that at least 60% pulverulent material is mixed with a binder. 15. The method of claim 14, characterized in that 70 to 80% of pulverulent material is mixed with 20 to 30% of binder. 16. The method of claim 2, characterized in that at least 60% of fibrous components are mixed with a binder. 17. Process according to claim 16, characterized in that 70 to 80% of fibrous components are mixed with 20 to 30% of binder. 18. Method according to any one of claims 1 or 2, characterized in that one uses a synthetic concrete as binder. 19. Method according to any one of claims 1 or 2, characterized in that at least one dye is introduced during the mixing operation with a binder. 20.  Process according to either of Claims 1 and 2, characterized in that at least one insert is placed in the mold prior to pouring a mass. 21. The method of claim 1, characterized in that one molds said masses and forms at least one space to remain empty of material within the material obtained after curing the binder. 22. Useful material especially for the construction or backfill, characterized in that it comprises at least 60% of a material free of metal bodies and obtained after grinding a mixture of waste containing powder components and fibrous components with an abrasive then removing said fibrous components and a binder based on synthetic resin. 23.  Material according to Claim 22, characterized in that the material is free from plastics and / or wood bodies. 24. Material according to claim 22, characterized in that it comprises at least 60% of a pulverulent material. 25. Material according to claim 24, characterized in that it comprises between 70 and 80% of pulverulent material. 26. Material according to claim 25, characterized in that the particle size of the pulverulent material is between that of sand and that of talc. 27. Material according to claim 22, characterized in that it comprises at least 60% of fibrous components. 28. Material according to claim 27, characterized in that it comprises between 70 and 80% of fibrous components. 29.  Material according to claim 22, characterized in that the abrasive consists of sand. 30. Material according to claim 22, characterized in that the abrasive consists of demolition debris free of metal bodies and comminuted. 31. Material according to claim 22, characterized in that the binder is a synthetic concrete. 32. Material according to claim 22, characterized in that it is fractionated into separate masses and each of said masses is shaped by molding, casting, or the like and then cured at room temperature. 33. Material according to claim 22, characterized in that it comprises at least one insert. 34. Material according to claim 22, characterized in that it comprises at least one empty space of material. 35.  Material according to claim 22, characterized in that it is colored.