FR2790980A1 - Complete recycling and treatment of communal industrial waste in mobile installation by combining dimensional reduction, crossed separation of components, and physico-chemical rendering of organic material inert - Google Patents

Abstract

Two reciprocally complementary treatment lines operating in the same assembly produce precise separation of different constituents into many useful fractions. Organic material is rapidly rendered inert by hydrolysis combined with removal of heavy metals by means of biodegradable basic reagents. Wastes are treated by combining dimensional reduction, crossed separation of the components of the treated material, and physico-chemical rendering of organic material inert.

Description

The invention applies to the technical field of industrial processing of

  waste. The waste particularly concerned is the ordinary industrial waste and the construction and demolition waste of the building and the public works which, even mixed and without preliminary sorting, can be inerted and revalorized by this new process. The goal is to prevent waste disposal and destruction by completely upgrading them as new materials. Some processes make it possible to separately sort and recycle various categories of waste, but without being able to recover the whole of a mass of mixed raw waste in the same unit of time and place. Other processes (especially thermal) massively inert the waste by causing the destruction of their main properties, thus opposing a revalorization of their material. Other processes insufficiently inert the organic part of the treated waste and leave it there.

  without treatment the amount of heavy metals they contain. Finally, a process similar to that developed in the present invention must expose the material to compression / expansion cycles of high amplitude, and to a prior dehydration, to be able to operate physicochemical inerting which requires more time and more heat. , without separating the treated material into several distinct reusable components.

  The method which is the subject of the invention manages to totally inert all the ordinary waste even unsorted at the entrance (organic and mineral fractions, including fermentable ones) at the same time and in the same place, without destroying their useful properties. , so as to make them directly reusable after treatment, for new industrial applications, especially as building materials, and in several separate forms. A

  important advantage of the process is to be able to achieve during the same reaction, physico-chemically, and at a temperature that can be less than 100 C, both the inerting of the organic part of the waste, by alkaline hydrolysis and also blocking the mass of heavy metals, which become leaching insoluble, without having to compress or dehydrate the treated material.

  The process is characterized by the combination of several treatment phases applied to the mass of waste to be treated, mainly including: - grinding, to achieve a fluidization of the mass of raw waste received, a homogenization of its particle size and its consistency, and an increase in its total area of contact and discrimination, the grinding being effected by a series of suitable mechanical grinders - a respective and cross separation of the metallic, inorganic, and organic physical elements, by magnetization, screening, and aerobic classification. densimetric - an impregnation, by transit and mixing in a kneader-reactor, to achieve both a basic hydrolysis of fermentable particles and a sequestration of heavy metals, made insoluble in leaching in aqueous phase, by means of a combination of reagents

  suitable chemicals, which can be premixed and used together without annoying each other.

  The process is also characterized by the simplification of its various phases and application means, which make possible, and even preferable, its implementation in autonomous installations consisting of moving and movable assemblies, on road trailers, or transportable compact chassis of the container type. Indeed, the method can be applied by means of successive functional modules, juxtaposed or superimposed, loosely interconnected by material transport devices, to form together a complete chain of treatment particularly autonomous and compact. A fixed installation can, however, also apply

the process.

  The effectiveness of the physico-chemical treatment requires the respect of the parameters of pressure, temperature, humidity, pH, duration of exposure, nature of the reactive components, proportions of the reagents, and contact surface. The finely ground material is pre-moistened to at least 35%, so as to avoid first, because of its large PCI and grinding fineness, any inflammation or deflagration during treatment or storage, which also reduces flying dust emissions. Then, the pre-humidification densifies the bulk density of the crushed organics, facilitates their transport, and improves the quality of the reaction.

chemical and reaction time.

  In the invention, the chemical reaction is sufficient to achieve total inerting of the material without having

  need to add a strong compression followed by sudden relaxation or dehydration.

  Improving the inerting performance is obtained by the quality and the proportion of the alkaline reagents, by the pre-humidification of the material, by its fine grinding, and by the injection of steam.

  pressurized water in the mixing kneader from the beginning of the reaction.

  The reagents that can be used are mainly calcium oxide, magnesium oxide, sodium hydroxide, or potassium hydroxide, in proportions ranging from 4% to 16% by weight relative to the mass of the materials. incoming to treat. The reaction is satisfactory at 80 ° C. with a reaction mixture at pH> 11. The sequestration of heavy metals in non-leachable complexes is optimized by adding silicates, aluminates or carbonates, especially sodium, to the mixture. The moisture of the material + reagents mixture is satisfactory from 50%. By respecting the above parameters, the inerting reaction can be prolonged without inconvenience several tens of minutes in the open air after leaving the mixer, and a

  impregnation by intensive mixing in the tank for a period of 4 minutes is satisfactory.

  The application of the process generates no pollution during the treatment applied to the material, no harmful residues, no hazardous effluent. In particular, the temperature rise limited to 100 C does not release any solvents, and does not create dioxins, furans, or other toxic compounds, nor dangerous gaseous releases (eg methane). The replacement of steam, for heating the material, by microwaves and / or by blowing hot air is possible. It is only necessary to correct in these cases the supply of moisture,

  by adding the equivalent of what is no longer provided by the water vapor.

  The final product obtained is sufficiently inert to be reusable, particularly as a construction material (for example, fillers for concrete), with the advantage of being separated into several distinct fractions of inert granulates and inert organic crumbs. In the absence of immediate use, all these fractions can be stored without any particular precautions in slag heaps, in silos or in burial. The advantage of the invention is in particular to be able to combine and integrate all the operations

  reduction and separation by versatile devices and reciprocally complementary.

  Thus, the separation of the inert and organic fractions of the treated material is carried out in a progressive manner and combined as and when the treatment. Indeed, the processing device constituted in application of the method comprises two distinct lines of treatment,

  interconnected to exchange reciprocally, after separation, certain elements of matter.

  Each line can process together the mixed organic and inert fractions of the incoming material. However, the first line is equipped with devices capable of handling the inert materials, usually the densest and the hardest, in the best conditions, and the second line is equipped with devices capable of best treating the organic materials, generally the lightest and the most flexible. Given the acceptable mixture of incoming waste, there may be some organic elements in the inert part, and vice versa. Each line is therefore equipped with separation devices that refer to

  the other line the part to be treated.

  Drawing 1 indicates the relationships and sequential concatenations that illustrate the co-ordinated complementary nature of the main phases of the process.

  Drawing 2 describes an example of application of the method in a mobile installation, that is to say whose equipment is installed on several road trailers, for the treatment of a mixture of inert waste building and public works (rubble and rubble) and ordinary industrial waste (wood, plastics, cardboard, textiles, etc.).

  The waste is first received in bulk on an entry depot area, where they are summarily

  divided into organic fat on one side and inert on the other. From there, loading machines extract them by appropriate means (eg buckets and grapples), to feed the first two grinders of the treatment plant, assembled and positioned near the deposit area. input. One of the input mills (1) is designed to process inert materials with maximum efficiency, and the other mill (2) is designed to preferentially treat organic materials. Each load discharged into a mill is composed for the most part of the material fraction chosen for this mill, but may also include a part of other material. A screening with densimetric sorting is therefore carried out at the bottom of the mill of the station 2, and the heavy inert elements recovered are conveyed by flexible belt conveyor to the mill of the station 1. Conversely, the organic elements ground with the inert at the station 1 are recovered in the central separator (4) and returned by pneumatic means (5) to the second crusher

  organic (6), where they are added to the ground material from the station 2 to be refined together.

  The refining is then completed by a very fine terminal grinding operated by one or more other mills (7) downstream. The physical metallic elements are separated from the mixed mass, immediately after the first grinding, by magnetic extraction (magnetization and eddy currents) (12) .5 The mixed material leaving the first grinding at the station 1 is driven by a conveyor belt a screen (3) which separates the finest heavy particles. The remainder of the crushed material is discharged into a multilevel aero-densimetric separator (4), which on the one hand separates inert and organic elements, and on the other separates the inert elements into several fractions of granulometries. The separated organic matter joined at station 6, as described above, the organic ground material from station 2, and the whole is gradually refined at station 7, then this

  material is poured into a buffer hopper (8) where it is premoistened by spraying with water.

  From this hopper, the wetted material is extracted to be introduced, in metered quantity, into a mixing battery (9), composed of one or more sealed mixing kneaders. The feed of the mixing battery can be carried out continuously or in batches. In case of batch feeding, the wetted material is discharged sequentially by gravity from a weigh hopper. As soon as the wetted material is introduced into the bowl of the kneader mixer, it is added the necessary proportion of reagents, and stirred for several minutes in the presence of steam injected under pressure at 100 C. The water is brought for a period of tank 20 (10), and the reagents are brought from a battery of proximity silos (11). Appropriate sensors continuously measure the temperature and humidity of the mixture. The material

  processed is then extracted from the mixing battery to accumulate in a maturation pile, where it remains one or more hours at room temperature. Therefore, the inerting of the treated organic part is complete and definitive, and the heavy metals are blocked in insoluble complexes. Several conveyor belts discharge into separate piles, away from the treatment devices, each separate part of the treated material.

  The invention is susceptible of industrial application by the assembly of complete mobile and autonomous waste treatment plants on site, the devices recommended for the application of the method can advantageously be assembled into movable and movable modules.

-5-

Claims (4)

  1) Non-polluting process of global treatment of the mixed waste, by combination of a dimensional reduction, a cross separation of all the components of the treated material, and a physicochemical inerting, applicable on mobile installations autonomous, and allowing a complete revalorization of the treated components, as new materials, without destroying their useful properties, at the same time and in the same place; characterized in that it is applicable by two different treatment lines reciprocally   complementary and interactive in the same set, realizing the precise separation of the various constituents of the treated material into several useful fractions, and also realizing the rapid inerting of the organic part of this material by a combined hydrolysis with a blocking of the heavy metals, to medium of biodegradable basic reagents.   2) Process according to claim 1, characterized by the coordinated treatment in two distinct lines of the predominantly organic part of one side and the predominantly mineral part of   the other, with separation and reciprocal exchange of fractions which interest the other line. 3) Process according to claims 1 and 2, characterized in that, in the case of its application to the   treatment of common mixed waste such as construction sites, these wastes are fully upgraded as new construction materials, after being separated into several grades of calibrated aggregates, as well as separate fractions of metals and residues. inerting organic matter (recyclithe). 4) Process according to claim 1, characterized in that the inerting is carried out rapidly by   physico-chemical route, resulting from the reaction of alkaline products in hot and humid confinement (eg 80 C to 50% humidity), mixed for a few minutes with the mass pre-   moistened and finely milled waste to be inert, so as to simultaneously perform a hydrolysis of this material and blocking in non-leachable complexes of heavy metals that may be contained therein, using a reduced proportional amount of reagents (from 4% by weight) relative to the treated material, this being compensated by a subsequent maturation in heap of the treated material for a few tens of minutes.   Process according to claims 1 and 4, characterized by a rapid reaction obtained in just a few minutes without the need to combine compression / expansion phases or   dehydration of the treated material. 6) Process according to claims 1-4 and 5, characterized by the use of a combination of reagents of mineral origin which are highly or completely biodegradable, such as calcium hydroxides,   potassium, or sodium, added with suitable silicates or aluminates, without harmful environmental impact when stored or used on site, capable of being premixed and used together without hindering.35 7) Process according to claims 1 to 6, characterized in that it is applicable by means of successive functional modules, juxtaposed or superimposed, loosely interconnected by devices   transport of material, to form a complete chain of treatment, autonomous and displaceable.