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WO1993013830A1 - Process and plant for the treatment of industrial synthesized gypsum residues - Google Patents

Process and plant for the treatment of industrial synthesized gypsum residues Download PDF

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Publication number
WO1993013830A1
WO1993013830A1 PCT/FR1993/000019 FR9300019W WO9313830A1 WO 1993013830 A1 WO1993013830 A1 WO 1993013830A1 FR 9300019 W FR9300019 W FR 9300019W WO 9313830 A1 WO9313830 A1 WO 9313830A1
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product
installation according
crusher
heating
installation
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French (fr)
Inventor
Françoise DUPRE
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Classifications

    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
    • A62D3/40—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by heating to effect chemical change, e.g. pyrolysis
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
    • A62D3/10—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by subjecting to electric or wave energy or particle or ionizing radiation
    • A62D3/17—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by subjecting to electric or wave energy or particle or ionizing radiation to electromagnetic radiation, e.g. emitted by a laser
    • A62D3/178—Microwave radiations, i.e. radiation having a wavelength of about 0.3 cm to 30cm
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
    • B01J19/12—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electromagnetic waves
    • B01J19/122—Incoherent waves
    • B01J19/126—Microwaves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
    • B09B3/50—Destroying solid waste or transforming solid waste into something useful or harmless involving radiation, e.g. electro-magnetic waves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00—Drying solid materials or objects by processes involving the application of heat
    • F26B3/32—Drying solid materials or objects by processes involving the application of heat by development of heat within the materials or objects to be dried, e.g. by fermentation or other microbiological action
    • F26B3/34—Drying solid materials or objects by processes involving the application of heat by development of heat within the materials or objects to be dried, e.g. by fermentation or other microbiological action by using electrical effects
    • F26B3/343—Drying solid materials or objects by processes involving the application of heat by development of heat within the materials or objects to be dried, e.g. by fermentation or other microbiological action by using electrical effects in combination with convection
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
    • A62D2101/40—Inorganic substances
    • A62D2101/41—Inorganic fibres, e.g. asbestos
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D2203/00—Aspects of processes for making harmful chemical substances harmless, or less harmful, by effecting chemical change in the substances
    • A62D2203/02—Combined processes involving two or more distinct steps covered by groups A62D3/10 - A62D3/40
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D2203/00—Aspects of processes for making harmful chemical substances harmless, or less harmful, by effecting chemical change in the substances
    • A62D2203/10—Apparatus specially adapted for treating harmful chemical agents; Details thereof

Definitions

  • the present invention relates to a process and its implementation in an installation allowing the almost total elimination of these three main nuisances to result in a variety of anhydrite.
  • the process consists in a first phase of concentrating part of the impurities and part of the acidity in the steam coming from a microwave oven, this condensable steam being made available to manufacturers who can extract the impurities and neutralize the acids, then, in a second phase, to transform, in a flow of hot air, the synthetic gypsum into an almost insoluble product whose final solidification ensures the sequestration of residual impurities.
  • Another object of the present invention is to provide an installation allowing the manufacture of anhydrite from residual synthetic gypsum.
  • Another object of the present invention is to provide an industrial waste treatment installation based on synthetic gypsum.
  • Another object of the present invention is to provide mobile units for this treatment.
  • the invention relates to a process for treating industrial synthetic gypsum which makes it possible to prevent the vapor flow produced by the dehydration of a given molecule from coming into contact with another already dehydrated molecule.
  • Gypsum waste is always rejected in the form of mud. After drying, we have a compact product, agglomerated into coherent blocks whose size can be reduced to around one centimeter by simple shaking. The desiccation is done by heating the waste by means of microwaves which have the characteristic of effectively heating only the water of imbibition, impregnation, (not chemically bound) and also have the property of drying materials while leaving from their center. Thus the vapor flow only crosses molecules which are still hydrated and the energy consumption is minimal since it is the water itself (therefore the gypsum) which heats and not the structure of the oven, and allows in particular a supply the temperature inside the cooking zone must be able to go up to 120 ° C. To reach such a temperature, the frequencies of the electromagnetic waves can be between 0.01 MHz and 10 8 MHz. The vapors are recovered by condensation and made available to manufacturers who can neutralize acids and extract impurities.
  • the product obtained after this first phase is dry and very brittle.
  • the product to be treated must have the largest possible heat exchange surface.
  • the process relating to this second phase consists in treating the powder in a stream of air advantageously heated between 180 ° C and 200 ° C and at a speed sufficient to keep the powder in suspension for the time necessary for the thermal equilibrium to be reached, knowing that the first molecule of water escapes around 128 ° C and the second molecule around 163 ° C.
  • the product is easily divided into friable powder but the insertion at the head of the circuit of a continuous bar mill makes it possible to refine the residual blocks of material to be treated.
  • the product is freed from its water of constitution so that one can speak of an "anhydrization".
  • the product obtained by this process has the characteristics of a particularly efficient hydraulic binder close to a variety of high strength plaster, for example of the gypsum hemihydrate or bassanite type.
  • This process has the advantage of not needing any chemical contribution.
  • This process also has the advantage of allowing the treatment of sludges having less than 70% relative humidity without prior preparation.
  • This process also has the advantage of allowing almost complete depollution of industrial residues without generating any pollution in the operation of its treatment installation.
  • This process has the characteristic of being a low consumer of electrical energy.
  • This process has the advantage of causing almost zero mechanical stress, therefore of preserving wear and deformation of the parts of the installation.
  • the residues to be treated are loaded automatically into a hopper.
  • the latter pours a quantity of residue determined by a weighing system into a baking oven (1);
  • the cooking oven (1) is based on the principle of the tunnel oven, that is to say that the products to be cooked are introduced intermittently into the cooking zone which will be hermetically sealed at its two ends.
  • This oven consists of a cooking zone which will use the energy supplied by electromagnetic wave generators. This area will be sealed by two doors, one (2) in the upper area, the other (3) in the lower area.
  • This cooking zone is usefully equipped with an acid vapor condenser (4) for recycling purposes.
  • a thermocouple and a humidity tester usefully equip this cooking zone. The opening and closing of these two doors are controlled by synchronous cylinders.
  • the dried product is conveyed by a continuous system (5) which feeds by gravity a flow control silo (6).
  • This silo is made of stainless steel. Its shape is conical. It is vertical with a large opening at the top and a smaller opening at the bottom.
  • This silo is equipped, inside, with a helical screw (7) without end which makes it possible to regulate the flow of flow of the dried product towards the low evacuation zone. Mouth low outlet is fitted with an adjustable hopper (8) allowing the flow rate of the dried product to be changed as desired.
  • This silo does not need to be heated directly: it simply works in a controlled temperature zone. The dried product is ejected from the control silo according to the controlled flow and, by simple gravitation, passes through a sieve cutter located immediately below the adjustable hopper (9).
  • the dried and sieved product is subjected to the current of hot air from a paddle fan (10) which creates a pneumatic flow allowing the transport of the dried product in a heated environment at 200 ° C. Behind this fan, at the fresh air inlet, is an electrical resistance (11) intended to heat the air called. This air flow propels the dried powdered product through a grinder-heater.
  • the air flow created by the fan allows the dried powder product to be transported through a continuous mill (12).
  • This cylindrical grinder has a length proportional to the speed of transport of the powder so that the thermal equilibrium is reached.
  • the cylinder is driven in a rotational movement by two gears (13) at each of its ends. Inside the cylinder are rollers of stainless steel resting without constraint at the bottom of the cylinder and free of any movement.
  • the interior of the cylinder is brought to the required temperature by a set of electrical resistors (14) arranged on the external surface of the cylinder with which they are integral.
  • this grinding cylinder can be carried out by replacing the electrical resistances with a polar liquid inside a cylinder with double insulated walls, boiling only at above 250 ° C, this installation having the advantage of an energy efficiency higher than the installation previously described.
  • the heating system then constituted by a burner can be located behind the paddle fan, the cylinder then being only provided with roughness over the entire length of its interior surface.
  • this grinding cylinder is mounted on an orientable frame (15). To prevent the grinding rollers from falling from the inclined cylinder, by the effect of the rotation, the lower end of the cylinder is partially closed by a disc pierced with outlets (16) allowing the powder to be extracted therefrom.
  • This disc is usefully provided with an inner belt on its smallest diameter thus preventing the crushing rollers from jumping out of the moving cylinder. Over a length of 10 cm preceding this same lower end, the cylinder is pierced on its walls with identical drainage holes.
  • a recovery system (17) for residual vapors is located at the lowest point of the cylinder immediately after the product has left the product.
  • the dried product is collected at the outlet of the grinder-heating cylinder by a stainless steel pipe which folds the pneumatic flow down towards a stall or a conveyor belt.
  • the installation according to the invention comprises a single microwave oven and a single grinder-heater cylinder.
  • the installation can also include even more depending on production requirements.
  • the installation then comprises several microwave ovens arranged in a "star” around a silo which distributes the dried product to as many grinder-heating cylinders also arranged in a "star".

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Environmental & Geological Engineering (AREA)
  • Electromagnetism (AREA)
  • Microbiology (AREA)
  • General Chemical & Material Sciences (AREA)
  • Biomedical Technology (AREA)
  • Biotechnology (AREA)
  • Organic Chemistry (AREA)
  • Molecular Biology (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Processing Of Solid Wastes (AREA)

Abstract

According to the process, the residues to be treated are firstly subjected to a baking process using electromagnetic waves, then to a pneumatic flux in a heated medium to produce an inert material in the form of anhydrite. The plant is characterized in that the residues to be treated are subjected to weighing, fed into an electromagnetic baking furnace (1 to 4), conveyed to a regulating silo fitted with a helicoidal screw (5 to 8), disintegrated and screened (9), carried by a pneumatic flux (10 and 11) into a grinding cylinder with heating rods (12 to 17), then collected in the form of anhydrite powder.

Description

PROCEDE ET INSTALLATION POUR LE TRAITEMENT DEPOLLUANT DES RESIDUS INDUSTRIELS DE GYPSES DE SYNTHESE PROCESS AND PLANT FOR THE TREATMENT OF DEPOLLUTING INDUSTRIAL RESIDUES FROM SYNTHESIS GYPSES

On sait actuellement qu'un énorme problème de stockage des déchets de gypses de synthèse se pose dans 5 le monde entier. Ces entreposages présentent les nuisances suivantes essentielles :It is currently known that a huge problem with the storage of synthetic gypsum waste arises worldwide. These warehouses present the following essential nuisances:

- nuisance due aux sulfates qui, sous forme colloïdale, suivent les mouvements des eaux souterraines- nuisance due to sulfates which, in colloidal form, follow the movement of groundwater

- nuisance due aux "impuretés" contenues dans ces gypses 10 et principalement composées par les fractions non récupérées du produit élaboré de l'usine productrice- nuisance due to the "impurities" contained in these gypsum 10 and mainly composed by the fractions not recovered from the product produced by the producing plant

- nuisance due à l'acidité des lixiviats, susceptible de remobiliser les métaux, notamment les métaux lourds.- nuisance due to the acidity of the leachate, capable of remobilizing metals, especially heavy metals.

D'une façon générale il est difficile, voireIn general it is difficult, even

15 impossible, de faire disparaître un corps gênant ; il convient donc de transformer ces boues, en 1'espèce, en un matériau inerte analogue somme toute aux roches minérales dont beaucoup sont issues.15 impossible, to remove a troublesome body; it is therefore advisable to transform this sludge, in the present case, into an inert material analogous after all to the mineral rocks from which many come.

Pour n'entraîner aucune nuisance un corps doit 20 être :In order to cause no harm, a body must be:

- solide, pour qu'il ne se répande pas hors du lieu où il a été déposé- solid, so that it does not spread outside the place where it was deposited

- inerte chimiquement et en particulier insoluble, d'une part parce qu'un corps "insoluble" n'est pratiquement- chemically inert and in particular insoluble, on the one hand because an "insoluble" body is practically

25 jamais toxique ne pouvant être assimilé par des "* organismes vivants, et d'autre part parce que les eaux de ruissellement peuvent alors être au contact de ce ^ corps sans modification de leur composition.25 never toxic can not be assimilated by "* living organisms, and secondly because the runoff can then be in contact with this ^ body without changing their composition.

Une telle transformation de résidus industriels 30 toxiques en un matériau inerte constitue un traitement ultime et d'une complète nouveauté.Such a transformation of toxic industrial residues into an inert material constitutes a treatment ultimate and completely new.

La présente invention est relative à un procédé et à sa mise en oeuvre dans une installation permettant l'élimination quasi-totale de ces trois nuisances principales pour aboutir à une variété d'anhydrite.The present invention relates to a process and its implementation in an installation allowing the almost total elimination of these three main nuisances to result in a variety of anhydrite.

Selon la présente invention, le procédé consiste dans une première phase à concentrer une partie des impuretés et une partie de l'acidité dans la vapeur issue d'un four à microondes, cette vapeur condensable étant remise à disposition des industriels qui pourront en extraire les impuretés et neutraliser les acides, puis, dans une seconde phase, à transformer, dans un flux d'air chaud, les gypses de synthèse en un produit quasi insoluble dont la prise en masse définitive assure la séquestration des impuretés résiduelles.According to the present invention, the process consists in a first phase of concentrating part of the impurities and part of the acidity in the steam coming from a microwave oven, this condensable steam being made available to manufacturers who can extract the impurities and neutralize the acids, then, in a second phase, to transform, in a flow of hot air, the synthetic gypsum into an almost insoluble product whose final solidification ensures the sequestration of residual impurities.

La réhydration ne pouvant intervenir qu'une seule fois il est indispensable d'éviter que le flux de vapeur produit par la déshydration d'une molécule arrive au contact d'une autre déjà déshydratée. Un autre but de la présente invention est de fournir une installation permettant la fabrication d'anhydrite à partir de gypses résiduels de synthèse.Since rehydration can only take place once, it is essential to avoid the vapor flow produced by the dehydration of one molecule coming into contact with another already dehydrated. Another object of the present invention is to provide an installation allowing the manufacture of anhydrite from residual synthetic gypsum.

Un autre but de la présente invention consiste à fournir une installation de traitement des déchets industriels à base de gypse de synthèse.Another object of the present invention is to provide an industrial waste treatment installation based on synthetic gypsum.

Un autre but de la présente invention consiste à fournir des unités mobiles pour ce traitement.Another object of the present invention is to provide mobile units for this treatment.

L'invention porte sur un procédé de traitement des gypses industriels de synthèse permettant d'éviter que le flux de vapeur produit par la déshydratation d'une molécule donnée arrive au contact d'une autre molécule déjà d shydratée.The invention relates to a process for treating industrial synthetic gypsum which makes it possible to prevent the vapor flow produced by the dehydration of a given molecule from coming into contact with another already dehydrated molecule.

Ce procédé permet d'obtenir un produit dépollué s'analysant en une variété d'anhydrite proche du plâtre. Ces résidus industriels présentent, dans leur entreposage, des nuisances essentiellement dues aux sulfates qui, sous forme colloïdale, suivent les mouvements des eaux souterraines, mais dues aussi aux "impuretés" contenues dans ces gypses et principalement composées par les fractions non récupérées du produit élaboré de l'usine productrice, et enfin dues à l'acidité des lixiviats susceptibles de remobiliser les métaux, notamment les métaux lourds. Il convient donc de concentrer une partie des impuretés et de 1'acidité dans une vapeur que l'on récupérera, puis de transformer, par traitement thermique, les sulfates en un produit quasi insoluble dont la prise en masse assure la séquestration des impuretés industrielles. Les déchets gypseux sont toujours rejetés sous forme de boue. Après ressuyage, on dispose d'un produit compact, aggloméré en blocs cohérents dont la taille peut être ramenée aux alentours du centimètre par simple secouement. La dessication se fait par chauffage des déchets au moyen de micro-ondes qui ont la caractéristique de ne chauffer efficacement que l'eau d'imbibition, d'imprégnation, (non liée chimiquement) et ont également la propriété de sécher des matériaux en partant de leur centre. Ainsi le flux de vapeur ne traverse que des molécules encore hydratées et la consommation d'énergie est minimale puisque c'est l'eau elle-même (donc le gypse) qui chauffe et non pas la structure du four, et permet notamment une alimentation en continu, la température à l'intérieur de la zone de cuisson doit pouvoir aller jusqu'à 120°C. Pour atteindre une telle température, les fréquences des ondes électromagnétiques peuvent être comprises entre 0,01 MHz et 108 MHz. Les vapeurs sont récupérées par condensation et remises à disposition des industriels qui pourront en neutraliser les acides et extraire les impuretés.This process makes it possible to obtain a depolluted product which analyzes into a variety of anhydrite close to plaster. These industrial residues present, in their storage, nuisances essentially due to sulphates which, in colloidal form, follow the movements of groundwater, but also due to the "impurities" contained in these gypsum and mainly composed by the fractions not recovered from the produced product of the producing plant, and finally due to the acidity of the leachate likely to remobilize metals, especially heavy metals. It is therefore advisable to concentrate a part of the impurities and of the acidity in a vapor which will be recovered, then to transform, by heat treatment, the sulphates into an almost insoluble product whose solidification ensures the sequestration of industrial impurities. Gypsum waste is always rejected in the form of mud. After drying, we have a compact product, agglomerated into coherent blocks whose size can be reduced to around one centimeter by simple shaking. The desiccation is done by heating the waste by means of microwaves which have the characteristic of effectively heating only the water of imbibition, impregnation, (not chemically bound) and also have the property of drying materials while leaving from their center. Thus the vapor flow only crosses molecules which are still hydrated and the energy consumption is minimal since it is the water itself (therefore the gypsum) which heats and not the structure of the oven, and allows in particular a supply the temperature inside the cooking zone must be able to go up to 120 ° C. To reach such a temperature, the frequencies of the electromagnetic waves can be between 0.01 MHz and 10 8 MHz. The vapors are recovered by condensation and made available to manufacturers who can neutralize acids and extract impurities.

Le produit obtenu après cette première phase est sec et très friable.The product obtained after this first phase is dry and very brittle.

La dessication complète s'obtient par chauffage de la poudre précédemment obtenue. Il est nécessaire que le produit à traiter présente la plus grande surface d'échange thermique possible. Le procédé relatif à cette seconde phase consiste à traiter la poudre dans un courant d'air chauffé avantageusement entre 180°C et 200°C et à une vitesse suffisante pour maintenir la poudre en suspension pendant le temps nécessaire pour que l'équilibre thermique soit atteint, sachant que la première molécule d'eau s'échappe aux alentours de 128°C et la seconde molécule aux alentours de 163°C. Le produit se divise facilement en poudre friable mais 1'insertion en tête de circuit d•un broyeur en continu à barres permet d'affiner les blocs résiduels de matière à traiter. Au terme de cette seconde phase, le produit est débarrassé de son eau de constitution de telle sorte qu'on peut parler d'une "anhydrisation".Complete drying is obtained by heating the powder previously obtained. The product to be treated must have the largest possible heat exchange surface. The process relating to this second phase consists in treating the powder in a stream of air advantageously heated between 180 ° C and 200 ° C and at a speed sufficient to keep the powder in suspension for the time necessary for the thermal equilibrium to be reached, knowing that the first molecule of water escapes around 128 ° C and the second molecule around 163 ° C. The product is easily divided into friable powder but the insertion at the head of the circuit of a continuous bar mill makes it possible to refine the residual blocks of material to be treated. At the end of this second phase, the product is freed from its water of constitution so that one can speak of an "anhydrization".

Le produit obtenu par ce procédé présente les caractéristiques d'un liant hydraulique particulièrement performant proche d'une variété de plâtre à haute résistance, par exemple de type hémihydrate de gypse ou bassanite.The product obtained by this process has the characteristics of a particularly efficient hydraulic binder close to a variety of high strength plaster, for example of the gypsum hemihydrate or bassanite type.

Ce procédé présente l'avantage de n'avoir besoin d'aucun apport chimique.This process has the advantage of not needing any chemical contribution.

Ce procédé présente aussi l'avantage de permettre le traitement des boues présentant moins de 70 % d'hygrométrie sans préparation préalable.This process also has the advantage of allowing the treatment of sludges having less than 70% relative humidity without prior preparation.

Ce procédé présente encore l'avantage de permettre une dépollution quasi intégrale des résidus industriels sans générer aucune pollution dans le fonctionnement de son installation de traitement. Ce procédé présente la caractéristique d'êtr faiblement consommateur d'énergie électrique.This process also has the advantage of allowing almost complete depollution of industrial residues without generating any pollution in the operation of its treatment installation. This process has the characteristic of being a low consumer of electrical energy.

Ce procédé présente l'avantage d'occasionner u effort mécanique quasi-nul, donc de préserver l'usure e la déformation des pièces de l'installation.This process has the advantage of causing almost zero mechanical stress, therefore of preserving wear and deformation of the parts of the installation.

Le procédé conforme à 1'invention est mis en oeuvre dans une installation combinant les moyens suivants :The process according to the invention is implemented in an installation combining the following means:

- les résidus à traiter sont chargés automatiquement dans une trémie. Celle-ci déverse une quantité de résidus déterminée par un système de pesage dans un four de cuisson (1) ;- the residues to be treated are loaded automatically into a hopper. The latter pours a quantity of residue determined by a weighing system into a baking oven (1);

- le four de cuisson (1) relève du principe du four tunnel, c'est à dire que les produits à cuire sont introduits par intermittences dans la zone-de cuisson qui sera fermée hermétiquement à ses deux extrémités. Ce four se compose d'une zone de cuisson qui utilisera l'énergie fournie par des générateurs d'ondes électromagnétiques. Cette zone sera fermée de manière étanche par deux portes situées l'une (2) en zone haute, l'autre (3) en zone basse. Cette zone de cuisson est utilement équipée d'un condenseur des vapeurs (4) acides aux fins de recyclage. Un thermo-couple et un testeur d'humidité équipent utilement cette zone de cuisson. L'ouverture et la fermeture de ces deux portes sont commandées par des vérins synchrones.- The cooking oven (1) is based on the principle of the tunnel oven, that is to say that the products to be cooked are introduced intermittently into the cooking zone which will be hermetically sealed at its two ends. This oven consists of a cooking zone which will use the energy supplied by electromagnetic wave generators. This area will be sealed by two doors, one (2) in the upper area, the other (3) in the lower area. This cooking zone is usefully equipped with an acid vapor condenser (4) for recycling purposes. A thermocouple and a humidity tester usefully equip this cooking zone. The opening and closing of these two doors are controlled by synchronous cylinders.

Au sortir de la zone de cuisson le produit séché est convoyé par un système en continu (5) qui alimente par gravité un silo de régulation de débit (6) .Leaving the cooking zone, the dried product is conveyed by a continuous system (5) which feeds by gravity a flow control silo (6).

Ce silo est fabriqué en acier inoxydable. Sa forme est conique. Il est vertical avec une grande ouverture en haut et une ouverture plus petite en bas. Ce silo est doté, à l'intérieur, d'une vis hélicoïdale (7) sans fin qui permet de réguler le flux d'écoulement du produit séché vers la zone basse d'évacuation. La bouche basse de sortie est dotée d'une trémie réglable (8) permettant de modifier à volonté le débit du produit séché. Ce silo n'a pas besoin d'être chauffé directement : il travaille simplement en zone de température dirigée. Le produit séché est éjecté du silo de régulation selon le flux maîtrisé et, par simple gravitation, passe au travers d'un désagrégeur-tamiseur situé immédiatement au dessous de la trémie réglable (9) .This silo is made of stainless steel. Its shape is conical. It is vertical with a large opening at the top and a smaller opening at the bottom. This silo is equipped, inside, with a helical screw (7) without end which makes it possible to regulate the flow of flow of the dried product towards the low evacuation zone. Mouth low outlet is fitted with an adjustable hopper (8) allowing the flow rate of the dried product to be changed as desired. This silo does not need to be heated directly: it simply works in a controlled temperature zone. The dried product is ejected from the control silo according to the controlled flow and, by simple gravitation, passes through a sieve cutter located immediately below the adjustable hopper (9).

Le produit séché et tamisé est soumis au courant d'air chaud d'un ventilateur à pales (10) qui crée un flux pneumatique permettant le transport du produit séché en ambiance chauffée à 200°C. En arrière de ce ventilateur, à l'entrée d'air frais, se trouve une résistance électrique (11) destinée à réchauffer l'air appelé. Ce flux d'air propulse le produit séché en poudre au travers d'un broyeur-chauffant.The dried and sieved product is subjected to the current of hot air from a paddle fan (10) which creates a pneumatic flow allowing the transport of the dried product in a heated environment at 200 ° C. Behind this fan, at the fresh air inlet, is an electrical resistance (11) intended to heat the air called. This air flow propels the dried powdered product through a grinder-heater.

Le flux d'air crée par le ventilateur permet le transport du produit séché en poudre au travers d'un broyeur en continu (12) . Ce broyeur de forme cylindrique a une longueur proportionnelle à la vitesse de transport de la poudre pour que l'équilibre thermique soit atteint. Le cylindre est entraîné dans un mouvement de rotation par deux engrenages (13) à chacune de ses extrémités. A l'intérieur du cylindre se trouvent des rouleaux d'acier inoxydable reposant sans contrainte au fond du cylindre et libres de tout mouvement.The air flow created by the fan allows the dried powder product to be transported through a continuous mill (12). This cylindrical grinder has a length proportional to the speed of transport of the powder so that the thermal equilibrium is reached. The cylinder is driven in a rotational movement by two gears (13) at each of its ends. Inside the cylinder are rollers of stainless steel resting without constraint at the bottom of the cylinder and free of any movement.

L'intérieur du cylindre est porté à la température requise par un ensemble de résistances électriques (14) disposées sur la surface externe du cylindre avec lequel elles font corps.The interior of the cylinder is brought to the required temperature by a set of electrical resistors (14) arranged on the external surface of the cylinder with which they are integral.

Sous une autre forme le chauffage de ce cylindre broyeur peut être effectué en remplaçant les résistances électriques par un liquide polaire à l'intérieur d'un cylindre à double parois isolées, ne bouillant qu'au dessus de 250°C, cette installation présentant l'avantage d'un rendement énergétique supérieur à l'installation précédemment décrite.In another form, the heating of this grinding cylinder can be carried out by replacing the electrical resistances with a polar liquid inside a cylinder with double insulated walls, boiling only at above 250 ° C, this installation having the advantage of an energy efficiency higher than the installation previously described.

Selon une autre forme d'exécution le système de chauffage constitué alors par un brûleur peut se situer en arrière du ventilateur à pales, le cylindre étant alors seulement doté d'aspérités sur toute la longueur de sa surface intérieure.According to another embodiment, the heating system then constituted by a burner can be located behind the paddle fan, the cylinder then being only provided with roughness over the entire length of its interior surface.

Pour assurer, quelque soit le cas de figure, une plus grande fluidité du transport du produit en poudre, ce cylindre-broyeur est monté sur un châssis orientable (15) . Pour éviter que les rouleaux de broyage tombent du cylindre incliné, par l'effet de la rotation, l'extrémité basse du cylindre est partiellement fermée par un disque percé d'évacuations (16) permettant à la poudre de s'en extraire. Ce disque est utilement doté d'une ceinture intérieure sur son diamètre le plus faible évitant ainsi aux rouleaux broyeurs de sauter hors du cylindre en mouvement. Sur une longueur de 10cm précédant cette même extrémité basse, le cylindre est percé sur ses parois de trous d'évacuations identiques.To ensure, whatever the scenario, greater fluidity in the transport of the powdered product, this grinding cylinder is mounted on an orientable frame (15). To prevent the grinding rollers from falling from the inclined cylinder, by the effect of the rotation, the lower end of the cylinder is partially closed by a disc pierced with outlets (16) allowing the powder to be extracted therefrom. This disc is usefully provided with an inner belt on its smallest diameter thus preventing the crushing rollers from jumping out of the moving cylinder. Over a length of 10 cm preceding this same lower end, the cylinder is pierced on its walls with identical drainage holes.

Un système de récupération (17) des vapeurs résiduelles se trouve au point le plus bas du cylindre dès après la sortie du produit. Un avantage important de l'utilisation d'un flux d'air est, aussi, qu'il assure la vidange complète de l'installation sans aucun problème technique.A recovery system (17) for residual vapors is located at the lowest point of the cylinder immediately after the product has left the product. An important advantage of using an air flow is also that it ensures complete emptying of the installation without any technical problem.

Le produit séché est récupéré au sortir du cylindre broyeur-chauffant par une canalisation en acier inoxydable qui rabat le flux pneumatique vers le bas en direction d'un bac de stabulation ou d'un tapis de convoyage.The dried product is collected at the outlet of the grinder-heating cylinder by a stainless steel pipe which folds the pneumatic flow down towards a stall or a conveyor belt.

Selon une première forme d'exécution, 1'installation conforme à 1'invention comporte un seul four à micro-ondes et un seul cylindre broyeur-chauffant. Elle peut toutefois aussi en comporter encore plus selon les exigences de production. Ainsi conformément à une autre forme d'exécution, l'installation comporte alors plusieurs fours à micro-ondes disposés en "étoile" autour d'un silo qui distribue le produit séché à autant de cylindres broyeur-chauffants également disposés en "étoile".According to a first embodiment, the installation according to the invention comprises a single microwave oven and a single grinder-heater cylinder. However, it can also include even more depending on production requirements. Thus, in accordance with another embodiment, the installation then comprises several microwave ovens arranged in a "star" around a silo which distributes the dried product to as many grinder-heating cylinders also arranged in a "star".

Le réglage de cette installation, quelle qu'en soit sa forme, présente une grande simplicité puisque la seule variable est le taux d'hygrométrie du produit à traiter. A titre indicatif un cylindre broyeur chauffant de 1,20 m de diamètre présentant une longueur utile de 4 m, demande un ventilateur générant 55 m3 par heure de débit pour générer 10 tonnes/heure de produit fini à partir du traitement d'environ 30 tonnes de déchets contenant 70 % d'humidité. The adjustment of this installation, whatever its form, is very simple since the only variable is the humidity level of the product to be treated. As an indication, a 1.20 m diameter heated grinding cylinder with a useful length of 4 m requires a fan generating 55 m 3 per hour of flow to generate 10 tonnes / hour of finished product from the treatment of approximately 30 tonnes of waste containing 70% humidity.

Claims

REVENDICATIONS 1 - Procédé de traitement de résidus gypseux de synthèse sous forme de boues en vue de les transformer en un matériau solide, insoluble dans l'eau et chimiquement inerte, caractérisé en ce que les boues, de teneur en humidité supérieure à 70 %, sont soumises à une dessication à température pouvant atteindre 120 °C au moyen d'ondes électro-magnétiques, avec récupération des vapeurs condensées, puis en ce que la matière sèche et friable obtenue est traitée, par gravitation, dans un courant d'air chauffé à température de 180 à 200°C à une vitesse suffisante pour maintenir la matière pulvérulente en suspension jusqu'à ce que l'équilibre thermique soit atteint.1 - Process for treating synthetic gypsum residues in the form of sludge with a view to transforming them into a solid material, insoluble in water and chemically inert, characterized in that the sludge, with a moisture content greater than 70%, is subjected to drying at a temperature of up to 120 ° C. by means of electromagnetic waves, with recovery of the condensed vapors, then in that the dry and friable material obtained is treated, by gravitation, in a stream of air heated to temperature from 180 to 200 ° C at a speed sufficient to maintain the pulverulent material in suspension until thermal equilibrium is reached. 2 - Procédé selon la revendication 1, caractérisé en ce que les ondes électromagnétiques ont des fréquences comprises entre 0,01 MHz et 108 MHz.2 - Method according to claim 1, characterized in that the electromagnetic waves have frequencies between 0.01 MHz and 10 8 MHz. 3 - Procédé selon la revendication 1, caractérisé en ce que le produit sec obtenu est ensuite soumis à un broyage chauffant, avec récupération des vapeurs résiduelles.3 - Method according to claim 1, characterized in that the dry product obtained is then subjected to a heating grinding, with recovery of residual vapors. 4 - Installation pour le traitement de résidus gypseux selon le procédé des revendications 1,2 ou 3, caractérisée en ce qu'elle comporte : a/un four-tunnel de cuisson (1) à ondes électro-magnétiques, muni de portes à fermeture étanche (2, 3) et d'un condenseur de vapeurs acides (4) aux fins de recyclage ; b/ un moyen de convoyage en continu (5) du produit séché ; c/ un silo de régulation de débit (6) alimenté par gravité en ledit produit et muni d'une vis hélicoïdale sans fin (7) ; d/ un désagrégateur-ta iseur (9) soumis par le bas à un courant d'air chaud à 180°C-200°C par des moyens de flux pneumatique ; e/ un broyeur chauffant (12) muni d'un système de récupération des vapeurs résiduelles (17) et à l'issu duquel on récupère le produit séché inerte.4 - Installation for the treatment of gypsum residues according to the method of claims 1,2 or 3, characterized in that it comprises: a / a baking tunnel oven (1) with electromagnetic waves, provided with closing doors sealed (2, 3) and an acid vapor condenser (4) for recycling; b / a means for continuously conveying (5) the dried product; c / a flow control silo (6) fed by gravity with said product and provided with an endless helical screw (7); d / a disaggregator-ta isor (9) subjected from below to a current of hot air at 180 ° C-200 ° C by pneumatic flow means; e / a heating mill (12) provided with a system for recovering residual vapors (17) and at the end of which the inert dried product is recovered. 5 - Installation selon la revendication 4, caractérisé en ce que les moyens générateurs de flux chaud pneumatique sont constitués par une ensemble de ventilateur à pâles (10) et une résistance électrique (11) , le flux d'air obtenu servant en outre à propulser le produit pulvérulent dans ledit broyeur chauffant (12).5 - Installation according to claim 4, characterized in that the pneumatic hot flow generating means consist of a fan assembly with blades (10) and an electrical resistance (11), the air flow obtained also serving to propel the pulverulent product in said heating mill (12). 6 - Installation selon l'une quelconque des revendications 4 et 5, caractérisée en ce que le broyeur (12) est constitué par un cylindre entraîné en rotation par des engrenages (13) et à l'intérieur duquel se meuvent librement des rouleaux d'acier inoxydable.6 - Installation according to any one of claims 4 and 5, characterized in that the crusher (12) consists of a cylinder driven in rotation by gears (13) and inside which freely move rollers stainless steel. 7 - Installation selon la revendication 6, caractérisée en ce que le broyeur (12) est muni, pour le chauffage, de résistances électriques (14) disposées sur la surface externe de celui-ci.7 - Installation according to claim 6, characterized in that the crusher (12) is provided, for heating, electrical resistors (14) disposed on the outer surface thereof. 8 - Installation selon la revendication 6, caractérisée en ce que le cylindre du broyeur est constitué par une double enveloppe dans laquelle circule un fluide calorifique.8 - Installation according to claim 6, characterized in that the mill cylinder is constituted by a double envelope in which circulates a heat fluid. 9 - Installation selon la revendication 6, caractérisée en ce que le broyeur (12) est chauffé par un brûleur externe.9 - Installation according to claim 6, characterized in that the crusher (12) is heated by an external burner. 10 - Installation selon l'une quelconque de revendications 6 à 9, caractérisée en ce que le broyeur est monté sur un châssis orientable (15) et en ce que l'extrémité basse de ce broyeur est fermée par un disque percé de trous d'évacuation (16) pour le produit pulvérulent final. 11 - Installation selon l'une quelconque des revendications 4 à 10, caractérisée en ce qu'elle comprend plusieurs fours (1) disposés en étoile autour d'un silo (6) qui distribue le produit séché à plusieurs cylindres-broyeurs chauffants (12) disposés également en étoile. 10 - Installation according to any one of claims 6 to 9, characterized in that the crusher is mounted on an orientable frame (15) and in that the lower end of this crusher is closed by a disc pierced with holes discharge (16) for the final pulverulent product. 11 - Installation according to any one of claims 4 to 10, characterized in that it comprises several ovens (1) arranged in a star around a silo (6) which distributes the dried product to several heating grinding rolls (12 ) also arranged in a star.
PCT/FR1993/000019 1992-01-10 1993-01-08 Process and plant for the treatment of industrial synthesized gypsum residues Ceased WO1993013830A1 (en)

Applications Claiming Priority (2)

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CH0051/92-5 1992-01-10
CH51/92A CH684191A5 (en) 1992-01-10 1992-01-10 Process and installation for the treatment of industrial residues of synthetic gypsum.

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FR2736419A1 (en) * 1995-07-03 1997-01-10 Aubert Bruno Incineration or processing of waste by RF or microwave heating - has material to be processed in reactor vessel containing two electrodes coupled to source of radio-frequency or microwave energy
ITUD20100166A1 (en) * 2010-09-16 2012-03-17 Thermopress Srl CDR-Q PRODUCTION SYSTEM
CN105417976A (en) * 2016-01-01 2016-03-23 澧县方石坪镇杨朴矿山机械厂 Continuous dehydrator for gypsum particles and technology control method thereof

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DE29505419U1 (en) * 1995-03-30 1995-07-13 Kollmer, Hansjakob, 77933 Lahr Device for drying and hardening orthopedic molded parts made of plaster
DE102006041656A1 (en) * 2006-08-24 2008-02-28 Paul Hartmann Ag Apparatus for the production of plaster bandages and method therefor

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EP0266437A1 (en) * 1986-10-31 1988-05-11 Wolfgang Dr. Pose Process and apparatus for neutralizing toxins and pollutants, especially products and objects which cause allergies when contacted by humans
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EP0145822A1 (en) * 1983-12-19 1985-06-26 COMPAGNIE FRANCAISE DES MICRO-RAYONNEMENTS, Société Anonyme française: Process and apparatus for drying moist products, in particular mixtures containing clay
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2736419A1 (en) * 1995-07-03 1997-01-10 Aubert Bruno Incineration or processing of waste by RF or microwave heating - has material to be processed in reactor vessel containing two electrodes coupled to source of radio-frequency or microwave energy
ITUD20100166A1 (en) * 2010-09-16 2012-03-17 Thermopress Srl CDR-Q PRODUCTION SYSTEM
CN105417976A (en) * 2016-01-01 2016-03-23 澧县方石坪镇杨朴矿山机械厂 Continuous dehydrator for gypsum particles and technology control method thereof

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ZA93138B (en) 1993-08-16
CH684191A5 (en) 1994-07-29
AU3455893A (en) 1993-08-03

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