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EP0687483A1 - Process for the treatment and conditioning of solid or liquid effluents charged with heavy metals - Google Patents

Process for the treatment and conditioning of solid or liquid effluents charged with heavy metals Download PDF

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Publication number
EP0687483A1
EP0687483A1 EP95401367A EP95401367A EP0687483A1 EP 0687483 A1 EP0687483 A1 EP 0687483A1 EP 95401367 A EP95401367 A EP 95401367A EP 95401367 A EP95401367 A EP 95401367A EP 0687483 A1 EP0687483 A1 EP 0687483A1
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EP
European Patent Office
Prior art keywords
treatment
solid
heavy metals
extraction
conditioning method
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EP95401367A
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German (de)
French (fr)
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EP0687483B1 (en
Inventor
Jean Leybros
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Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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Commissariat a lEnergie Atomique CEA
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    • 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
    • A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
    • A62D3/37—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by reduction, e.g. hydrogenation
    • 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
    • A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
    • A62D3/33—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by chemical fixing the harmful substance, e.g. by chelation or complexation
    • 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
    • A62D2101/20—Organic substances
    • A62D2101/24—Organic substances containing heavy metals
    • 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
    • A62D2101/43—Inorganic substances containing heavy metals, in the bonded or free state
    • 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

Definitions

  • the present invention relates to a process for the treatment and conditioning of solid or liquid effluents loaded with heavy metals. It aims to treat effluents from, for example, chemical processes for surface treatment, waste incineration processes or any other process leading to the formation of effluents heavily loaded with heavy metals and therefore extremely toxic. This process allows, more particularly, the selective recovery of these heavy metals with respect to chlorine or to alkali or alkaline earth metals.
  • the solid waste produced by these different chemical processes is particularly toxic for the environment because it has a fairly large soluble fraction which prevents its storage in landfills.
  • the volumes of liquid effluents formed are generally very large.
  • a medium-sized company working in this type of industry can generate up to a tonne per year of sludge concentrated in metals. This represents extremely significant pollution throughout the national territory.
  • the purification technique for this type of effluent generally consists of carrying out a conventional neutralization and precipitation treatment, so as to form sludges liable to be stored in landfills of class "I" (that is to say an impermeable site intended to receive special industrial waste).
  • This waste or this residue comprises approximately 30% by weight of the initial bottom ash product, 3% by weight of the initial fly ash product and of the dechlorination products of the fumes (hereinafter referred to as REFIOM, i.e. REsidues Household Waste Incineration Smoke), the rest being non-condensable products.
  • REFIOM i.e. REsidues Household Waste Incineration Smoke
  • the bottom clinkers are relatively chemically inert and can be used after conditioning in road construction or be stored in landfills of class "II" (that is to say a semi-permeable site intended to receive ordinary industrial waste), or even in class III landfills (that is to say a permeable site receiving only inert waste).
  • fly ash formed by fine particles entrained by combustion gases and by gas neutralization products, have highly polluting characteristics, due to the high rate of the soluble fraction
  • the polluting fraction consists essentially of heavy metals, the most common of which are zinc, lead, cadmium and chromium.
  • composition of these "REFIOM” is very variable and depends on the techniques used for the purification of the fumes from the incineration processes (techniques by dry, semi-wet or wet routes).
  • REFIOMs can be washed with water, which allows the soluble fraction containing the majority of heavy metals to be entrained.
  • the leachate is treated with sodium hydroxide which allows on the one hand the precipitation of these metals in the form of hydroxide and their recycling with the insoluble part resulting from the preliminary washing operation, the whole being able to be vitrified, and on the other hand the production of a sodium effluent containing the non-toxic anions and cations to be treated later.
  • the wet processes can operate in a similar fashion, except washing, since the recovered effluent is already in the form of a suspension which undergoes the same precipitation treatment as previously described.
  • the solid residue obtained can also be vitrified.
  • vitrification requires compliance with a number of criteria.
  • the vitrified elements must be digestible in the glass, so as to avoid the formation of heterogeneous phases or precipitates in large quantities.
  • the anions (Cl, F, PO4, SO4) are the most troublesome elements due to their low solubility in glass which causes phase separations.
  • the glasses then obtained are non-homogeneous and of poor quality, because the molten salt phase which is not vitrified contains a non-negligible proportion of toxic cations.
  • the molten salt phases being lighter than the glass itself, the fairly high volatility of these salts is further increased by their contact with the gaseous atmosphere.
  • waste and glass must be compatible.
  • the treated effluents may contain a high proportion (that is to say more than 50% by weight) of alkali metal salts (sodium and potassium) or alkaline earth metal salts (magnesium and calcium ). These salts do not present any particular nuisance for the environment and it is not necessary to make them inert in a specific matrix.
  • the object of the invention is to carry out a process for the treatment and conditioning of solid or liquid effluents loaded with heavy metals which make it possible to selectively separate from the effluent, chlorine and alkali or alkaline-earth metals in order to make the toxic residual fraction of the effluent containing heavy metals vitrifiable.
  • This process applies to the treatment of various effluents and in particular solid or liquid effluents from chemical surface treatment processes or waste incineration processes.
  • the process according to the invention allows selective recovery of heavy metals with respect to chlorine and to alkali or alkaline-earth metals and this in a solid form which is perfectly suitable for vitrification.
  • the solvent containing an extractant and a hydrocarbon must be chosen appropriately.
  • the hydrocarbon used is generally hydrogenated tetrapropylene (TPH).
  • TPH tetrapropylene
  • an agent preventing the separation of the extractant and the diluent for example a heavy alcohol C10 to C14, may be necessary.
  • the dilution factor should not be too large in order to be able to strongly concentrate the metals and not to have to increase the size of the extraction apparatus.
  • the solvent is preferably diluted until it titers 0.2 to 1.0 mole of organophosphorus extractant per liter of hydrocarbon or better 0.6 mole per liter. This reduces the density of the viscosity of the organic solvent while increasing its interfacial tension with the aqueous contact solutions. Therefore, the first extraction step can take place at room temperature (20 to 25 ° C), which reduces its cost.
  • the quality of the extraction is highly dependent on the pH of the aqueous phase.
  • the acidity of the aqueous phase increases. Care should therefore be taken to maintain the pH value as constant as possible by injections of a neutralizing agent at predetermined positions in the extraction apparatus.
  • the pH of the aqueous phase is preferably maintained at a value between 4.5 and 6.5, or better still between 5.0 and 6.0 depending on the extractant used.
  • the neutralizing agent used to adjust the pH is a concentrated sodium hydroxide solution.
  • the second extraction step can be carried out at room temperature (approximately 20 to 25 ° C), it is preferable to carry it out hot, that is to say between approximately 40 and 60 ° C, preferably 50 ° C, if you wish to purify the solvent from all of the metals before recycling it in the first extraction device.
  • This hot treatment also has the advantage of avoiding the precipitation of lead chloride, the solubility of which is more limited in the second extraction apparatus.
  • the precipitation step transforms the metals into insoluble carbonates, that is to say a chemical form suitable for vitrification.
  • insoluble carbonates that is to say a chemical form suitable for vitrification.
  • powdered sodium carbonate or in solution at 200 g / l or powdered calcium carbonate which quantitatively precipitate the most troublesome heavy metals, such as cadmium, nickel, lead and zinc.
  • the precipitation pH is chosen at a value between 8 and 10, or better still 9, to limit the redissolution of aluminum and chromium hydroxides in particular.
  • This precipitation step is generally carried out between 40 and 60 ° C or better about 50 ° C, which increases the speed of formation and maturation of the precipitates and makes it possible to avoid the untimely precipitation of lead chloride.
  • the installation necessary for the implementation of the method according to the invention comprises six chemical engineering equipments, namely two extraction apparatuses, referenced 2 and 4 respectively, of the pulsed column type, an apparatus precipitation device 6, of the ripener-thickener type, a filtration device 8, of the continuous vacuum filter type with drum or strips or of the discontinuous filter type with press and vitrification equipment 10.
  • this device can also include concentration equipment 12.
  • a leaching device 14 advantageously consisting of an apparatus of the stirred tank type, mounted in cascade and the volume and number of which is adapted to the flow rate of the waste to be treated and by a filtration device 16, of the continuous vacuum type drum or band filter, or of the discontinuous press filter type.
  • the operation of this device will now be described in more detail, in the case of effluents to be treated which are in solid form.
  • the solid effluent 18 is introduced with concentrated hydrochloric acid 20 into the leaching device 14 where the reaction takes place between 40 and 80 ° C.
  • a control of the pH of the solid-liquid suspension 22 leaving the leaching device makes it possible to adjust the flow rate of hydrochloric acid 20.
  • the pH is maintained between 0.5 and 3.0.
  • the solid-liquid suspension 22 is introduced into the filtration device 16.
  • the solid cake is washed with water 24 and the liquid filtrate 26 is recovered.
  • the mother liquors from washing 28 are recycled to the leaching device 14 where they constitute the leaching solution.
  • the flow rate of washing water 24 is adapted to the flow rate of solid waste, so as to obtain a filtrate 26 containing between 5 and 20% by weight of solids and a washed residual solid 30 containing less than 1% of chlorides.
  • a reducing agent 32 and a filtrate 34 from the filtration device 8 are added to the filtrate 26 (or liquid effluent) as will be described later so as to form a mother solution 36.
  • This is introduced at one end of the extraction apparatus 2, in which the non-alkaline and non-alkaline earth cations are selectively extracted from the anions, against the flow of an organic extraction solvent 38 introduced at the other end of the apparatus .
  • the reducing agent 32 is, for example, sodium bisulfite, sodium metabisulfite, ferrous sulfate or sulfur dioxide.
  • the pH of the aqueous phase is adjusted by injections of a neutralizing agent at different points, referenced respectively 40, 42 and 44.
  • the relative flow rate of the two solutions is adjusted so that the raffinate 46 leaving the first device contain less than 15.0 mg / l of heavy metals.
  • the solvent 38 comes from the second extraction device 4.
  • the organic solution loaded with heavy metals 48 leaving the first extraction device 2 enters the second extraction device 4 where it is treated counter-current and hot with an aqueous solution of hydrochloric acid 50.
  • the acid titer of this aqueous solution of hydrochloric acid is such that the solvent 38 leaving the second extraction device 4 is sufficiently discharged not to generate leaks of heavy metals and in particular cadmium greater than 0.2 mg / l in the raffinate 46.
  • the aqueous extraction solution 52 loaded with heavy metals, originating from the extraction apparatus 4, is introduced hot into the precipitation apparatus 6 where it is treated using a precipitation agent 54 which can advantageously be sodium or calcium carbonate.
  • a precipitation agent 54 which can advantageously be sodium or calcium carbonate. This carbonate maintains a sufficiently alkaline pH for which the heavy metals are thus precipitated in the form of carbonates, the chloride anions remaining in solution.
  • the solid-liquid suspension 56 from the precipitation apparatus 6 is introduced into the filtration apparatus 8 and the filtrate obtained is recycled at 34.
  • the solid precipitate 64 is washed by introduction of water at 58, while the waters outgoing washing mothers 60 are recycled to the extraction apparatus 4.
  • the flow rate of washing water used is at least equal to the flow rate necessary for diluting the hydrochloric acid 62 introduced.
  • the mother liquors from washing 60 and hydrochloric acid form the aqueous solution 50 introduced into the second extraction device 4.
  • the aqueous solution 50 contains between 0.1 and 6.0 mol / l hydrochloric acid.
  • the relative flow rates of the washing water 58 and the hydrochloric acid are further adjusted so that the solvent 38 contains less than 50 mg / l of heavy metals.
  • the washed precipitate containing less than 1% of chlorides 64 is treated with the residual solid 30 in the vitrification device 10 to produce an inert glass 66.
  • the raffinate 46 can be treated in the concentration device 8 in order to recover, on the one hand, recyclable water 68, salts 70 crystallized or in the form of brine.
  • Sodium metabisulfite is added at a rate of 50 mg / l.
  • the mother solution 36 and the organic solvent 38 are introduced into the first extraction device 2 with a solvent flow rate equal to 0.2 times the flow rate of the aqueous phase.
  • the pH is checked at 5.5 by adding 1.0 N NaOH.
  • the organic solvent 38 titers 0.6 M / l of bis- (2,4,4-trimethylpentyl) -monothiophosphinic acid in TPH.
  • the organic solution loaded with heavy metals 48 is treated in the second extraction device 4, against the flow of a 3N hydrochloric acid solution whose volume flow is five times lower than the flow of organic phase.
  • the first extraction operation 2 is carried out at an average temperature of the order of 22 ° C, while the second extraction operation 4 is carried out at the average temperature of the order of 50 ° C.
  • the de-extracted solvent 38 recovered contains less than 15 mg / l of residual heavy metals.
  • the pH is equal to 1.8.
  • Sodium metabisulfite is added at a rate of 20 mg / l.
  • the mother solution 36 and the organic solvent 38 are introduced into the first extraction device 2 with a flow rate of solvent equal to 0.2 times the flow rate of aqueous phase.
  • the pH is checked at 5.5 by adding 1.0 N NaOH.
  • the organic solvent 38 titers 0.6 M / l of di- (2-ethylhexyl) -manothiophosphoric acid in TPH.
  • the organic solution loaded with heavy metals 48 is treated in the second extraction device 4, against the flow of a 3N hydrochloric acid solution whose volume flow is 5 times lower than the flow of organic phase.
  • the first extraction operation 2 is carried out at an average temperature of the order of 22 ° C, while the second extraction operation 4 is carried out at an average temperature of 50 ° C.
  • the de-extracted solvent 38 recovered contains less than 15 mg / l of residual heavy metals.

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Extraction Or Liquid Replacement (AREA)
  • Removal Of Specific Substances (AREA)
  • Processing Of Solid Wastes (AREA)

Abstract

Processing of solid or liq. effluents contg. heavy metals comprises: (a) treating a liq. effluent or liq. extract of a solid effluent with a reducing agent to obtain a process soln.; (b) contacting the process soln. with a solvent in a first extraction vessel, where the solvent is capable of selectively extracting heavy metals, anions and alkali(ne earth)metals and comprises an organophosphorus extractant and a hydrocarbon; (c) passing the organic phase from (b) to a second extraction vessel and contacting it with an aq. soln. capable of extracting heavy metals from the organic phase; (d) contacting the aq. phase from (c) with a pptn. capable of precipitating. all the heavy metals in the form of insoluble and vitrifiable chemical species; (e) filtering off the ppte. and washing it with water; (f) recycling the filtrate from (e) for addn. to the process soln. from (a); and (g) vitrifying the ppte. from (e).

Description

La présente invention concerne un procédé de traitement et de conditionnement d'effluents solides ou liquides chargés en métaux lourds. Il a pour but de traiter des effluents issus, par exemple, des procédés chimiques de traitement de surfaces, des procédés d'incinération des déchets ou de tout autre procédé conduisant à la formation d'effluents fortement chargés en métaux lourds et donc extrêmement toxiques. Ce procédé permet, plus particulièrement, la récupération sélective de ces métaux lourds par rapport au chlore ou aux métaux alcalins ou alcalino-terreux.The present invention relates to a process for the treatment and conditioning of solid or liquid effluents loaded with heavy metals. It aims to treat effluents from, for example, chemical processes for surface treatment, waste incineration processes or any other process leading to the formation of effluents heavily loaded with heavy metals and therefore extremely toxic. This process allows, more particularly, the selective recovery of these heavy metals with respect to chlorine or to alkali or alkaline earth metals.

Les déchets solides produits par ces différents procédés chimiques sont particulièrement toxiques pour l'environnement car ils présentent une fraction soluble assez importante qui interdit leur entreposage en décharge.The solid waste produced by these different chemical processes is particularly toxic for the environment because it has a fairly large soluble fraction which prevents its storage in landfills.

Par ailleurs, dans l'industrie du traitement de surfaces par voie chimique par exemple, les volumes d'effluents liquides formés sont généralement très importants. A titre d'exemple, une entreprise de taille moyenne travaillant dans ce type d'industrie peut générer jusqu'à une tonne par an de boues concentrées en métaux. Ceci représente une pollution extrêmement importante sur l'ensemble du territoire national.Furthermore, in the chemical surface treatment industry for example, the volumes of liquid effluents formed are generally very large. For example, a medium-sized company working in this type of industry can generate up to a tonne per year of sludge concentrated in metals. This represents extremely significant pollution throughout the national territory.

La technique d'épuration de ce type d'effluents consiste généralement à effectuer un traitement classique de neutralisation et de précipitation, de façon à former des boues susceptibles d'être entreposées dans les décharges de classe "I" (c'est-à-dire un site imperméable destiné à recevoir des déchets industriels spéciaux).The purification technique for this type of effluent generally consists of carrying out a conventional neutralization and precipitation treatment, so as to form sludges liable to be stored in landfills of class "I" (that is to say an impermeable site intended to receive special industrial waste).

On peut citer également, à titre d'exemple, les résidus formés par les procédés d'incinération de déchets ménagers. Ces déchets ou ces résidus comprennent environ 30 % en poids du produit initial de mâchefers, 3 % en poids du produit initial de cendres volantes et des produits de déchloruration des fumées (dénommés ci-après REFIOM, c'est-à-dire des REsidus de Fumée d'Incinération d'Ordures Ménagères), le reste étant constitué par des produits incondensables. Les mâchefers sont relativement inertes chimiquement et peuvent être utilisés après conditionnement dans la construction de route ou être entreposés dans des décharges de classe "II" (c'est-à-dire un site semi-perméable destiné à recevoir des déchets industriels banaux), voire même dans des décharges de classe III, (c'est-à-dire un site perméable recevant uniquement des déchets inertes) . En revanche, les cendres volantes, constituées par de fines particules entraînées par les gaz de combustion et par les produits de neutralisation des gaz, présentent des caractéristiques fortement polluantes, dues au taux élevé de la fraction soluble à forte teneur en composés métalliques lourds lixiviables.Mention may also be made, by way of example, of residues formed by household waste incineration processes. This waste or this residue comprises approximately 30% by weight of the initial bottom ash product, 3% by weight of the initial fly ash product and of the dechlorination products of the fumes (hereinafter referred to as REFIOM, i.e. REsidues Household Waste Incineration Smoke), the rest being non-condensable products. The bottom clinkers are relatively chemically inert and can be used after conditioning in road construction or be stored in landfills of class "II" (that is to say a semi-permeable site intended to receive ordinary industrial waste), or even in class III landfills (that is to say a permeable site receiving only inert waste). On the other hand, fly ash, formed by fine particles entrained by combustion gases and by gas neutralization products, have highly polluting characteristics, due to the high rate of the soluble fraction with a high content of leachable heavy metal compounds.

Enfin, à titre d'exemple, les installations d'incinération françaises ont ainsi produit en 1991 environ 240 000 tonnes de REFIOM. En général, les constituants de ces REFIOM sont les suivants :

  • calcium 10 à 30 % ;
  • chlore 10 à 25 % ;
  • sulfate 15 à 25 % ;
  • silicium 3 à 15 % ;
  • aluminium 2 à 6 % ;
  • potassium 1 à 7 % ;
  • sodium 1 à 4 % ; et
  • métaux lourds 3 à 4%.
Finally, by way of example, French incineration plants thus produced in 1991 around 240,000 tonnes of REFIOM. In general, the constituents of these REFIOMs are as follows:
  • calcium 10 to 30%;
  • chlorine 10 to 25%;
  • sulfate 15-25%;
  • silicon 3 to 15%;
  • aluminum 2 to 6%;
  • potassium 1 to 7%;
  • sodium 1 to 4%; and
  • heavy metals 3 to 4%.

La fraction polluante est essentiellement constituée par les métaux lourds dont les plus courants sont le zinc, le plomb, le cadmiun et le chrome.The polluting fraction consists essentially of heavy metals, the most common of which are zinc, lead, cadmium and chromium.

Toutefois, la composition de ces "REFIOM" est très variable et dépend des techniques mises en oeuvre pour l'épuration des fumées issues des procédés d'incinération (techniques par voies sèche, semi-humide ou humide).However, the composition of these "REFIOM" is very variable and depends on the techniques used for the purification of the fumes from the incineration processes (techniques by dry, semi-wet or wet routes).

A titre d'exemple, dans les procédés d'incinération en voie sèche ou semi-humide les REFIOM pourront être lavés à l'eau ce qui permet d'entraîner la fraction soluble contenant la majorité des métaux lourds. Les lixiviats sont traités par de la soude qui permet d'une part la précipitation de ces métaux sous forme d'hydroxyde et leur recyclage avec la partie insoluble issue de l'opération préliminaire de lavage, l'ensemble pouvant être vitrifié, et d'autre part la production d'un effluent sodique contenant les anions et les cations non toxiques à traiter ultérieurement. Les procédés par voie humide peuvent fonctionner de façon similaire, excepté le lavage, puisque l'effluent récupéré est déjà sous la forme d'une suspension qui subit les mêmes traitement de précipitation que précédemment décrit. Le résidu solide obtenu pourra aussi être vitrifié.For example, in dry or semi-wet incineration processes, REFIOMs can be washed with water, which allows the soluble fraction containing the majority of heavy metals to be entrained. The leachate is treated with sodium hydroxide which allows on the one hand the precipitation of these metals in the form of hydroxide and their recycling with the insoluble part resulting from the preliminary washing operation, the whole being able to be vitrified, and on the other hand the production of a sodium effluent containing the non-toxic anions and cations to be treated later. The wet processes can operate in a similar fashion, except washing, since the recovered effluent is already in the form of a suspension which undergoes the same precipitation treatment as previously described. The solid residue obtained can also be vitrified.

On connaît déjà d'après l'art antérieur de nombreux procédés de traitement de ces "REFIOM", associés ou non à un traitement ultérieur de vitrification. De tels procédés consistent généralement à précipiter ou à fixer les métaux lourds en traitant l'effluant liquide lui-même ou une solution de lavage des "REFIOM" dans une colonne échangeuse d'ions, (voir par exemple US4873065 ou US5041398).Numerous methods for treating these "REFIOMs" are already known from the prior art, associated or not with a subsequent vitrification treatment. Such methods generally consist in precipitating or fixing the heavy metals by treating the liquid effluent itself or a washing solution. "REFIOM" in an ion exchange column, (see for example US4873065 or US5041398).

Les procédés connus présentent de nombreux inconvénients, tels que l'extraction incomplète des métaux lourds, la formation d'un résidu final insuffisamment stabilisé se présentant sous forme de boues uniquement susceptibles d'être stockées dans des décharges contrôlées (classe I) ou encore la quantité importante d'additifs à mettre en oeuvre qui entraîne des coûts d'exploitation élevés.The known methods have many drawbacks, such as the incomplete extraction of heavy metals, the formation of an insufficiently stabilized final residue in the form of sludge only capable of being stored in controlled landfills (class I) or the large quantity of additives to be used which results in high operating costs.

De plus, la mise en oeuvre de la vitrification impose le respect d'un certain nombre de critères. Ainsi, les éléments vitrifiés doivent être digestibles dans le verre, de façon à éviter la formation de phases hétérogènes ou de précipités en grande quantité. Les anions (Cl, F, PO₄, SO₄) sont les éléments les plus gênants du fait de leur faible solubilité dans le verre qui provoque des séparations de phases. Les verres alors obtenus sont non homogènes et de mauvaise qualité, car la phase de sels fondus qui n'est pas vitrifiée contient une proportion non négligeable de cations toxiques. De plus, les phases de sel fondu étant plus légères que le verre lui-même, la volatilité assez grande de ces sels est encore accrue par leur contact avec l'atmosphère gazeuse. En outre, les déchets et le verre doivent être compatibles.In addition, the implementation of vitrification requires compliance with a number of criteria. Thus, the vitrified elements must be digestible in the glass, so as to avoid the formation of heterogeneous phases or precipitates in large quantities. The anions (Cl, F, PO₄, SO₄) are the most troublesome elements due to their low solubility in glass which causes phase separations. The glasses then obtained are non-homogeneous and of poor quality, because the molten salt phase which is not vitrified contains a non-negligible proportion of toxic cations. In addition, the molten salt phases being lighter than the glass itself, the fairly high volatility of these salts is further increased by their contact with the gaseous atmosphere. In addition, waste and glass must be compatible.

Par ailleurs, quelques soient les effluents traités, c'est-à-dire des effluents liquides ou des cendres volantes, un traitement de déchloruration sera nécessaire. Dans le cas des "REFIOM", le traitement en vue du confinement par vitrification nécessite toujours une opération préliminaire de lixiviation chimique destinée à extraire le chlorure. La fraction insoluble est constituée essentiellement de silice et d'alumine, ainsi que de quelques oxydes métalliques aisément vitrifiables.Furthermore, whatever the effluents treated, that is to say liquid effluents or fly ash, a dechlorination treatment will be necessary. In the case of "REFIOM", treatment for confinement by vitrification always requires a preliminary chemical leaching operation intended to extract the chloride. The insoluble fraction consists essentially of silica and alumina, as well as some easily vitrifiable metal oxides.

Enfin, les effluents traités peuvent contenir une forte proportion, (c'est-à-dire plus de 50 % en poids), de sels de métaux alcalins, (sodium et potassium) ou des sels de métaux alcalino-terreux (magnésium et calcium). Ces sels ne présentent pas de nuisances particulières pour l'environnement et il n'est pas nécessaire de les rendre inertes dans une matrice spécifique.Finally, the treated effluents may contain a high proportion (that is to say more than 50% by weight) of alkali metal salts (sodium and potassium) or alkaline earth metal salts (magnesium and calcium ). These salts do not present any particular nuisance for the environment and it is not necessary to make them inert in a specific matrix.

Malgré tous les inconvénients et exigences précités, la technique de vitrification reste extrêmement intéressante.Despite all the above drawbacks and requirements, the vitrification technique remains extremely interesting.

En conséquence, l'invention a pour but de réaliser un procédé de traitement et de conditionnement d'effluents solides ou liquides chargés en métaux lourds qui permettent de séparer sélectivement de l'effluent, le chlore et les métaux alcalins ou alcalino-terreux afin de rendre vitrifiable la fraction résiduelle toxique de l'effluent contenant les métaux lourds.Consequently, the object of the invention is to carry out a process for the treatment and conditioning of solid or liquid effluents loaded with heavy metals which make it possible to selectively separate from the effluent, chlorine and alkali or alkaline-earth metals in order to make the toxic residual fraction of the effluent containing heavy metals vitrifiable.

Selon une caractéristique de l'invention, ce procédé comprend les étapes consistant à :

  • a) réduire chimiquement à l'aide d'un agent réducteur l'effluent liquide ou l'effluent solide traité de façon à se présenter sous forme liquide, l'ajuster en pH pour obtenir.une solution réduite ;
  • b) mettre, dans un premier appareil d'extraction, cette solution mère en contact avec un solvant organique contenant essentiellement un extractant organophosphoré et un hydrocarbure capable d'extraire sélectivement les métaux lourds, des anions et des métaux alcalins et alcalino-terreux ;
  • c) mettre, dans un deuxième appareil d'extraction, la solution organique chargée en métaux lourds et issue du premier appareil d'extraction, en contact avec une solution aqueuse capable d'extraire les métaux lourds de la phase organique ;
  • d) mettre en contact la solution aqueuse issue de l'appareil d'extraction avec un agent de précipitation capable de précipiter la totalité des métaux lourds contenus dans la solution aqueuse sous la forme d'espèces chimiques insolubles et vitrifiables ;
  • e) filtrer la suspension obtenue, puis laver le précipité solide à l'eau afin de le séparer des eaux mères de lavage ; et
  • f) vitrifier le précipité lavé filtré.
According to a characteristic of the invention, this method comprises the steps consisting in:
  • a) chemically reduce using a reducing agent the liquid effluent or the solid effluent treated so as to be in liquid form, adjust it to pH to obtain a reduced solution;
  • b) putting, in a first extraction device, this mother solution in contact with an organic solvent essentially containing an organophosphorus extractant and a hydrocarbon capable of selectively extracting heavy metals, anions and alkali and alkaline earth metals;
  • c) put, in a second extraction device, the organic solution loaded with metals heavy and from the first extraction device, in contact with an aqueous solution capable of extracting heavy metals from the organic phase;
  • d) bringing the aqueous solution from the extraction apparatus into contact with a precipitation agent capable of precipitating all of the heavy metals contained in the aqueous solution in the form of insoluble and vitrifiable chemical species;
  • e) filter the suspension obtained, then wash the solid precipitate with water in order to separate it from the washing mother liquors; and
  • f) vitrify the filtered washed precipitate.

Ce procédé s'applique au traitement de divers effluents et notamment des effluents solides ou liquides issus des procédés chimiques de traitement de surface ou des procédés d'incinération de déchets. Le procédé selon l'invention permet une récupération sélective des métaux lourds par rapport au chlore et aux métaux alcalins ou alcalino-terreux et ce sous une forme solide convenant parfaitement à la vitrification. On récupère également des sels inertes vis-à-vis de l'environnement et qui peuvent être utilisés en technique routière par exemple.This process applies to the treatment of various effluents and in particular solid or liquid effluents from chemical surface treatment processes or waste incineration processes. The process according to the invention allows selective recovery of heavy metals with respect to chlorine and to alkali or alkaline-earth metals and this in a solid form which is perfectly suitable for vitrification. We also recover inert salts vis-à-vis the environment and which can be used in road engineering for example.

Pour extraire les métaux de façon sélective, le solvant contenant un extractant et un hydrocarbure doit être choisi de façon appropriée.To selectively extract metals, the solvent containing an extractant and a hydrocarbon must be chosen appropriately.

Le choix de l'extractant est lié à la présence ou non de calcium dans l'effluent à traiter. Ainsi, en présence de calcium, on utilisera avantageusement l'acide bis-(2,4,4-trimethylpentyl)-monothiophosphinique du fait de son bon pouvoir d'extraction et de sa bonne sélectivité vis-à-vis des métaux alcalins et alcalino-terreux ou encore l'acide di-(2-éthylhexyl)-monothiophosphorique malgré une sélectivité légèrement moins bonne. Au contraire, en l'absence de calcium, on utilisera avantageusement l'acide di-(2-éthylhexyl)-phosphorique, l'acide di-(2,4,4-trimethylpentyl)-phosphinique, le mono(2-ethylhexyl) ester de l'acide (2-éthylhexyl)-phosphonique.The choice of extractant is linked to the presence or not of calcium in the effluent to be treated. Thus, in the presence of calcium, bis- (2,4,4-trimethylpentyl) -monothiophosphinic acid will advantageously be used because of its good extraction power and its good selectivity with respect to alkali and alkali metals. -terreous or di- (2-ethylhexyl) -monothiophosphoric acid despite a slightly selective less good. On the contrary, in the absence of calcium, di- (2-ethylhexyl) -phosphoric acid, di- (2,4,4-trimethylpentyl) -phosphinic acid, mono (2-ethylhexyl) will be used. ester of (2-ethylhexyl) -phosphonic acid.

L'hydrocarbure utilisé est en général le tétrapropylène hydrogéné (TPH). Dans certains cas, l'ajout d'un agent empêchant la séparation de l'extractant et du diluant, par exemple un alcool lourd en C10 à C14, peut s'avérer nécessaire.The hydrocarbon used is generally hydrogenated tetrapropylene (TPH). In some cases, the addition of an agent preventing the separation of the extractant and the diluent, for example a heavy alcohol C10 to C14, may be necessary.

Au cours des diverses étapes d'extraction du procédé, il est souhaitable d'une part de concentrer fortement les métaux extraits et d'autre part d'éviter la formation d'émulsions difficiles à décanter et qui nuiraient au bon fonctionnement hydrodynamique des appareils d'extraction. Il convient donc de veiller d'une part à utiliser un solvant très concentré et d'autre part à ce que la phase organique soit plus légère que la phase aqueuse. C'est la raison pour laquelle on doit diluer l'extractant organophosphoré pur, (par exemple l'acide bis-(2,4,4-triméthylpentyl)-monothiophosphinique ; densité 0,93 et viscosité 195 centipoises, par un hydrocarbure liquide moins dense par exemple le TPH ; densité 0,76).During the various stages of extraction of the process, it is desirable on the one hand to strongly concentrate the metals extracted and on the other hand to avoid the formation of emulsions difficult to decant and which would harm the good hydrodynamic functioning of the apparatuses 'extraction. Care should therefore be taken on the one hand to use a highly concentrated solvent and on the other hand to ensure that the organic phase is lighter than the aqueous phase. This is the reason why the pure organophosphorus extractant (for example bis- (2,4,4-trimethylpentyl) -monothiophosphinic acid; density 0.93 and viscosity 195 centipoise) must be diluted with a liquid hydrocarbon less dense for example TPH; density 0.76).

Toutefois, le facteur de dilution ne doit pas être trop important afin de pouvoir concentrer fortement les métaux et de ne pas avoir à augmenter la taille de l'appareil d'extraction. En pratique, on dilue de préférence le solvant jusqu'à ce qu'il titre 0,2 à 1,0 mole d'extractant organophosphoré par litre d'hydrocarbure ou mieux 0,6 mole par litre. On diminue ainsi la densité de la viscosité du solvant organique tout en augmentant sa tension interfaciale avec les solutions aqueuses de contact. De ce fait, la première étape d'extraction peut avoir lieu à température ambiante (20 à 25°C), ce qui réduit son coût.However, the dilution factor should not be too large in order to be able to strongly concentrate the metals and not to have to increase the size of the extraction apparatus. In practice, the solvent is preferably diluted until it titers 0.2 to 1.0 mole of organophosphorus extractant per liter of hydrocarbon or better 0.6 mole per liter. This reduces the density of the viscosity of the organic solvent while increasing its interfacial tension with the aqueous contact solutions. Therefore, the first extraction step can take place at room temperature (20 to 25 ° C), which reduces its cost.

Au cours des deux étapes d'extraction du procédé, des précipitations de sels métalliques, suivies de leur redissolution sont possibles. Dans un mélangeur décanteur, ces précipités se rassemblent au fond des bacs de décantation et deviennent inaccessibles au solvant. Aussi, de façon avantageuse, les deux étapes d'extractions sont effectuées dans une colonne pulsée car ces appareils sont peu sensibles à la présence de matières solides. Ceci permet d'éviter le problème précité.During the two stages of extraction of the process, precipitation of metal salts, followed by their redissolution is possible. In a settling mixer, these precipitates collect at the bottom of the settling tanks and become inaccessible to the solvent. Also, advantageously, the two extraction steps are carried out in a pulsed column because these devices are not very sensitive to the presence of solid matter. This avoids the above problem.

La qualité de l'extraction est fortement dépendante du pH de la phase aqueuse. Or, au cours de l'extraction des métaux qui s'effectue par échange de cations, l'acidité de la phase aqueuse augmente. On veillera donc à maintenir la valeur du pH la plus constante possible par des injections d'un agent neutralisant à des positions prédéterminées dans l'appareil d'extraction. Le pH de la phase aqueuse est de préférence maintenu à une valeur comprise entre 4,5 et 6,5, ou mieux entre 5,0 et 6,0 en fonction de l'extractant utilisé. De façon avantageuse, l'agent neutralisant mis en oeuvre pour ajuster le pH est une solution d'hydroxyde de sodium concentré.The quality of the extraction is highly dependent on the pH of the aqueous phase. However, during the extraction of metals which is carried out by cation exchange, the acidity of the aqueous phase increases. Care should therefore be taken to maintain the pH value as constant as possible by injections of a neutralizing agent at predetermined positions in the extraction apparatus. The pH of the aqueous phase is preferably maintained at a value between 4.5 and 6.5, or better still between 5.0 and 6.0 depending on the extractant used. Advantageously, the neutralizing agent used to adjust the pH is a concentrated sodium hydroxide solution.

Bien que la deuxième étape d'extraction puisse être réalisée à température ambiante (20 à 25°C environ), il est préférable de l'effectuer à chaud, c'est-à-dire entre 40 et 60°C environ, de préférence 50°C, si l'on souhaite épurer le solvant de la totalité des métaux avant son recyclage dans le premier appareil d'extraction. Ce traitement à chaud présente aussi l'avantage d'éviter la précipitation du chlorure de plomb dont la solubilité est plus limitée dans le deuxième appareil d'extraction.Although the second extraction step can be carried out at room temperature (approximately 20 to 25 ° C), it is preferable to carry it out hot, that is to say between approximately 40 and 60 ° C, preferably 50 ° C, if you wish to purify the solvent from all of the metals before recycling it in the first extraction device. This hot treatment also has the advantage of avoiding the precipitation of lead chloride, the solubility of which is more limited in the second extraction apparatus.

L'étape de précipitation permet de transformer les métaux en carbonates insolubles, c'est-à-dire une forme chimique convenant à la vitrification. On utilise avantageusement le carbonate de sodium pulvérulant ou en solution à 200 g/l ou encore du carbonate de calcium pulvérulant qui précipitent de façon quantitative les métaux lourds les plus gênants, tels que le cadmium, le nickel, le plomb et le zinc. De préférence, le pH de précipitation est choisi à une valeur comprise entre 8 et 10, ou mieux 9, pour limiter la redissolution des hydroxydes d'aluminium et de chrome notamment. Cette étape de précipitation est généralement effectuée entre 40 et 60°C ou mieux environ 50°C, ce qui accroît la vitesse de formation et de mûrissement des précipités et permet d'éviter la précipitation intempestive de chlorure de plomb.The precipitation step transforms the metals into insoluble carbonates, that is to say a chemical form suitable for vitrification. Advantageously using powdered sodium carbonate or in solution at 200 g / l or powdered calcium carbonate which quantitatively precipitate the most troublesome heavy metals, such as cadmium, nickel, lead and zinc. Preferably, the precipitation pH is chosen at a value between 8 and 10, or better still 9, to limit the redissolution of aluminum and chromium hydroxides in particular. This precipitation step is generally carried out between 40 and 60 ° C or better about 50 ° C, which increases the speed of formation and maturation of the precipitates and makes it possible to avoid the untimely precipitation of lead chloride.

Enfin, lorsque l'effluent à traiter est sous forme solide, le procédé selon l'invention comprend une première série d'étapes ayant pour but de rendre cet effluent liquide. Ceci est réalisé :

  • en mettant dans un dispositif de lixiviation l'effluent solide à traiter en contact avec une solution de lixiviation et un acide minéral dilué avec une solution aqueuse et capable de solubiliser la fraction soluble de l'effluent solide pour former une suspension ;
  • en introduisant cette suspension dans un dispositif de filtration, afin de la séparer en un solide résiduel insoluble et en un effluent liquide à introduire dans le premier appareil d'extraction ; et
  • en lavant le solide résiduel insoluble par de l'eau.
Finally, when the effluent to be treated is in solid form, the method according to the invention comprises a first series of steps intended to make this effluent liquid. This is achieved:
  • by putting in a leaching device the solid effluent to be treated in contact with a leaching solution and a mineral acid diluted with an aqueous solution and capable of dissolving the soluble fraction of the solid effluent to form a suspension;
  • by introducing this suspension into a filtration device, in order to separate it into an insoluble residual solid and into a liquid effluent to be introduced into the first extraction apparatus; and
  • by washing the residual insoluble solid with water.

D'autres caractéristiques et avantages de l'invention ressortiront mieux à la lecture de la description suivante, donnée à titre d'exemple illustratif et non limitatif et faite en faisant référence à la figure unique jointe, représentant de façon schématique l'installation nécessaire à la mise en oeuvre du procédé selon l'invention.Other characteristics and advantages of the invention will emerge more clearly on reading the following description, given by way of illustrative and nonlimiting example and made with reference to the attached single figure, schematically representing the installation necessary for the implementation of the method according to the invention.

Comme illustré sur la figure jointe, l'installation nécessaire à la mise en oeuvre du procédé selon l'invention comprend six équipements de génie chimique, à savoir deux appareils d'extraction, référencés respectivement 2 et 4, du type colonne pulsée, un appareil de précipitation 6, du type murisseur-épaississeur, un appareil de filtration 8, du type filtre continu sous vide à tambour ou à bandes ou du type filtre discontinu à presse et un équipement de vitrification 10. De façon facultative, ce dispositif peut également comprendre un équipement de concentration 12.As illustrated in the attached figure, the installation necessary for the implementation of the method according to the invention comprises six chemical engineering equipments, namely two extraction apparatuses, referenced 2 and 4 respectively, of the pulsed column type, an apparatus precipitation device 6, of the ripener-thickener type, a filtration device 8, of the continuous vacuum filter type with drum or strips or of the discontinuous filter type with press and vitrification equipment 10. Optionally, this device can also include concentration equipment 12.

Lorsque l'effluent à traiter est sous forme liquide, cette installation est suffisante. Toutefois, lorsque l'effluent à traiter se présente sous forme solide, l'installation précitée est complétée par un dispositif de lixiviation 14, constitué avantageusement d'un appareil du type à cuves agitées, montées en cascade et dont le volume et le nombre est adapté au débit des déchets à traiter et par un dispositif de filtration 16, du type filtre continu sous vide à tambour ou à bandes, ou du type filtre discontinu à presse.When the effluent to be treated is in liquid form, this installation is sufficient. However, when the effluent to be treated is in solid form, the aforementioned installation is completed by a leaching device 14, advantageously consisting of an apparatus of the stirred tank type, mounted in cascade and the volume and number of which is adapted to the flow rate of the waste to be treated and by a filtration device 16, of the continuous vacuum type drum or band filter, or of the discontinuous press filter type.

Le fonctionnement de ce dispositif va maintenant être décrit plus en détail, dans le cas d'effluents à traiter se présentant sous forme solide. L'effluent solide 18 est introduit avec de l'acide chlorhydrique concentré 20 dans le dispositif de lixiviation 14 où la réaction a lieu entre 40 et 80°C. Un contrôle du pH de la suspension solide-liquide 22 sortant du dispositif de lixiviation permet d'ajuster le débit d'acide chlorhydrique 20. Le pH est maintenu entre 0,5 et 3,0. La suspension solide-liquide 22 est introduite dans le dispositif de filtration 16. Le gâteau solide est lavé par de l'eau 24 et le filtrat 26 liquide est récupéré. Les eaux mères de lavage 28 sont recyclées dans le dispositif de lixiviation 14 où elles constituent la solution de lixiviation. De façon avantageuse, le débit de l'eau de lavage 24 est adapté au débit des déchets solides, de façon à obtenir un filtrat 26 contenant entre 5 et 20 % en poids de solides et un solide résiduel lavé 30 contenant moins de 1 % de chlorures.The operation of this device will now be described in more detail, in the case of effluents to be treated which are in solid form. The solid effluent 18 is introduced with concentrated hydrochloric acid 20 into the leaching device 14 where the reaction takes place between 40 and 80 ° C. A control of the pH of the solid-liquid suspension 22 leaving the leaching device makes it possible to adjust the flow rate of hydrochloric acid 20. The pH is maintained between 0.5 and 3.0. The solid-liquid suspension 22 is introduced into the filtration device 16. The solid cake is washed with water 24 and the liquid filtrate 26 is recovered. The mother liquors from washing 28 are recycled to the leaching device 14 where they constitute the leaching solution. Advantageously, the flow rate of washing water 24 is adapted to the flow rate of solid waste, so as to obtain a filtrate 26 containing between 5 and 20% by weight of solids and a washed residual solid 30 containing less than 1% of chlorides.

La description qui va suivre est commune au traitement du filtrat 26 issu du dispositif de filtration 16 ou à un effluent à traiter se présentant directement sous forme liquide.The description which follows is common to the treatment of the filtrate 26 from the filtration device 16 or to an effluent to be treated which is presented directly in liquid form.

On ajoute au filtrat 26 (ou effluent liquide) un agent réducteur 32 et un filtrat 34 issu du dispositif de filtration 8 comme cela sera décrit ultérieurement de façon à former une solution mère 36. Celle-ci est introduite à l'une des extrémités de l'appareil d'extraction 2, dans lequel les cations non alcalins et non alcalino-terreux sont extraits de façon sélective des anions, à contre-courant d'un solvant organique d'extraction 38 introduit à l'autre extrémité de l'appareil. L'agent réducteur 32 est par exemple le bisulfite de sodium, le métabisulfite de sodium, le sulfate ferreux ou le dioxyde de soufre.A reducing agent 32 and a filtrate 34 from the filtration device 8 are added to the filtrate 26 (or liquid effluent) as will be described later so as to form a mother solution 36. This is introduced at one end of the extraction apparatus 2, in which the non-alkaline and non-alkaline earth cations are selectively extracted from the anions, against the flow of an organic extraction solvent 38 introduced at the other end of the apparatus . The reducing agent 32 is, for example, sodium bisulfite, sodium metabisulfite, ferrous sulfate or sulfur dioxide.

Le pH de la phase aqueuse est ajusté par des injections d'un agent neutralisant en différents points, référencés respectivement 40, 42 et 44. Le débit relatif des deux solutions est ajusté de telle façon que le raffinat 46 sortant du premier appareil d'extraction contiennent moins de 15,0 mg/l de métaux lourds.The pH of the aqueous phase is adjusted by injections of a neutralizing agent at different points, referenced respectively 40, 42 and 44. The relative flow rate of the two solutions is adjusted so that the raffinate 46 leaving the first device contain less than 15.0 mg / l of heavy metals.

De façon avantageuse, mais non obligatoire, le solvant 38 provient du deuxième appareil d'extraction 4. La solution organique chargée en métaux lourds 48 sortant du premier appareil d'extraction 2 pénètre dans le deuxième appareil d'extraction 4 où elle est traitée à contre-courant et à chaud par une solution aqueuse d'acide chlorhydrique 50. Le titre en acide de cette solution aqueuse d'acide chlorhydrique est tel que le solvant 38 sortant du deuxième appareil d'extraction 4 est suffisamment déchargé pour ne pas générer de fuites en métaux lourds et en particulier en cadmium supérieures à 0,2 mg/l dans le raffinat 46.Advantageously, but not compulsory, the solvent 38 comes from the second extraction device 4. The organic solution loaded with heavy metals 48 leaving the first extraction device 2 enters the second extraction device 4 where it is treated counter-current and hot with an aqueous solution of hydrochloric acid 50. The acid titer of this aqueous solution of hydrochloric acid is such that the solvent 38 leaving the second extraction device 4 is sufficiently discharged not to generate leaks of heavy metals and in particular cadmium greater than 0.2 mg / l in the raffinate 46.

La solution aqueuse d'extraction 52 chargée en métaux lourds, issus de l'appareil d'extraction 4, est introduite à chaud dans l'appareil de précipitation 6 où elle est traitée à l'aide d'un agent de précipitation 54 qui peut être avantageusement du carbonate de sodium ou de calcium. Ce carbonate maintient un pH suffisamment alcalin pour lequel les métaux lourds sont ainsi précipités sous forme de carbonates, les anions chlorures restant en solution.The aqueous extraction solution 52 loaded with heavy metals, originating from the extraction apparatus 4, is introduced hot into the precipitation apparatus 6 where it is treated using a precipitation agent 54 which can advantageously be sodium or calcium carbonate. This carbonate maintains a sufficiently alkaline pH for which the heavy metals are thus precipitated in the form of carbonates, the chloride anions remaining in solution.

La suspension solide-liquide 56 issue de l'appareil de précipitation 6 est introduite dans l'appareil de filtration 8 et le filtrat obtenu est recyclé en 34. Le précipité solide 64 est lavé par introduction d'eau en 58, tandis que les eaux mères de lavage sortant 60 sont recyclées dans l'appareil d'extraction 4. Le débit d'eau de lavage mis en oeuvre est au moins égal au débit nécessaire à la dilution de l'acide chlorhydrique 62 introduit. Les eaux mères de lavage 60 et l'acide chlorhydrique forment la solution aqueuse 50 introduite dans le deuxième appareil d'extraction 4. De préférence, la solution aqueuse 50 contient entre 0,1 et 6,0 mol/l d'acide chlorhydrique. Les débits relatifs de l'eau de lavage 58 et de l'acide chlorhydrique sont en outre ajustés pour que le solvant 38 contienne moins de 50 mg/l de métaux lourds.The solid-liquid suspension 56 from the precipitation apparatus 6 is introduced into the filtration apparatus 8 and the filtrate obtained is recycled at 34. The solid precipitate 64 is washed by introduction of water at 58, while the waters outgoing washing mothers 60 are recycled to the extraction apparatus 4. The flow rate of washing water used is at least equal to the flow rate necessary for diluting the hydrochloric acid 62 introduced. The mother liquors from washing 60 and hydrochloric acid form the aqueous solution 50 introduced into the second extraction device 4. Preferably, the aqueous solution 50 contains between 0.1 and 6.0 mol / l hydrochloric acid. The relative flow rates of the washing water 58 and the hydrochloric acid are further adjusted so that the solvent 38 contains less than 50 mg / l of heavy metals.

Ensuite, le précipité lavé contenant moins de 1 % de chlorures 64 est traité avec le solide résiduel 30 dans le dispositif de vitrification 10 pour produire un verre inerte 66.Then, the washed precipitate containing less than 1% of chlorides 64 is treated with the residual solid 30 in the vitrification device 10 to produce an inert glass 66.

De façon facultative, le raffinat 46 peut être traité dans le dispositif de concentration 8 afin de récupérer, d'une part, de l'eau recyclable 68, des sels 70 cristallisés ou sous forme de saumûre.Optionally, the raffinate 46 can be treated in the concentration device 8 in order to recover, on the one hand, recyclable water 68, salts 70 crystallized or in the form of brine.

On donne ci-après, des exemples de mise en oeuvre du procédé conforme à l'invention.Examples of implementation of the process according to the invention are given below.

Exemple 1Example 1

Dans une installation analogue à celle qui vient d'être décrite, on traite un "REFIOM" par une solution d'acide chlorhydrique 1,5 N, le filtrat 26 obtenu présente la composition suivante :
[C1⁻] = 41,5 g/l   [Ca²⁺] = 28 g/l
[Na⁺] = 1,66 g/l   [K⁺] = 3,25 g/l
[Cd²] = 21 mg/l   [Zn²⁺] = 1 060 mg/l
[Pb²] = 380 mg/l   [CrVI] = 4,3 mg/l
[Fe³] = 100 mg/l   [Mn²⁺] = 22,0 mg/l
[Mg²] = 600 mg/l   [Ba²⁺] = 8,0 mg/l
et divers autres éléments à moindre concentration, tels que Ni, Co et V. Le pH est égal à 1,7.In an installation similar to that which has just been described, a "REFIOM" is treated with a 1.5N hydrochloric acid solution, the filtrate 26 obtained has the following composition:
[C1⁻] = 41.5 g / l [Ca²⁺] = 28 g / l
[Na⁺] = 1.66 g / l [K⁺] = 3.25 g / l
[Cd²] = 21 mg / l [Zn²⁺] = 1060 mg / l
[Pb²] = 380 mg / l [Cr VI ] = 4.3 mg / l
[Fe³] = 100 mg / l [Mn²⁺] = 22.0 mg / l
[Mg²] = 600 mg / l [Ba²⁺] = 8.0 mg / l
and various other elements at lower concentrations, such as Ni, Co and V. The pH is equal to 1.7.

On ajoute du métabisulfite de sodium à raison de 50 mg/l. La solution mère 36 et le solvant organique 38 sont introduits dans le premier appareil d'extraction 2 avec un débit de solvant égal à 0,2 fois le débit de phase aqueuse. On contrôle le pH à 5,5 par ajout de NaOH 1,0 N.Sodium metabisulfite is added at a rate of 50 mg / l. The mother solution 36 and the organic solvent 38 are introduced into the first extraction device 2 with a solvent flow rate equal to 0.2 times the flow rate of the aqueous phase. The pH is checked at 5.5 by adding 1.0 N NaOH.

Le solvant organique 38 titre 0,6 M/l d'acide bis-(2,4,4-triméthylpentyl)-monothiophosphinique dans le TPH.The organic solvent 38 titers 0.6 M / l of bis- (2,4,4-trimethylpentyl) -monothiophosphinic acid in TPH.

Le raffinat 46 obtenu présente la composition suivante :
[C1⁻] = 39,5 g/l   [Ca²⁺] = 26,3 g/l
[Na⁺] = 1,64 g/l   [K⁺] = 3,22 g/l
[Cd²⁺] ≦ 1 mg/l   [Zn²⁺] ≦ 1 mg/l
[Pb²⁺] ≦ 1 mg/l   [Cr³⁺] = 1,4 mg/l
[Fe²⁺] = 95 mg/l   [Mn²⁺] ≦ 1 mg/l
[Mg²⁺] = 590 mg/l   [Ba²⁺] = 6,5 mg/lThe raffinate 46 obtained has the following composition:
[C1⁻] = 39.5 g / l [Ca²⁺] = 26.3 g / l
[Na⁺] = 1.64 g / l [K⁺] = 3.22 g / l
[Cd²⁺] ≦ 1 mg / l [Zn²⁺] ≦ 1 mg / l
[Pb²⁺] ≦ 1 mg / l [Cr³⁺] = 1.4 mg / l
[Fe²⁺] = 95 mg / l [Mn²⁺] ≦ 1 mg / l
[Mg²⁺] = 590 mg / l [Ba²⁺] = 6.5 mg / l

La solution organique chargée en métaux lourds 48 est traitée dans le deuxième appareil d'extraction 4, à contre-courant d'une solution d'acide chlorhydrique 3 N dont le débit volume est cinq fois plus faible que le débit de phase organique.The organic solution loaded with heavy metals 48 is treated in the second extraction device 4, against the flow of a 3N hydrochloric acid solution whose volume flow is five times lower than the flow of organic phase.

La première opération d'extraction 2 est réalisée à une tempérture moyenne de l'ordre de 22°C, tandis que la deuxième opération d'extraction 4 est réalisée à la température moyenne de l'ordre de 50°C.The first extraction operation 2 is carried out at an average temperature of the order of 22 ° C, while the second extraction operation 4 is carried out at the average temperature of the order of 50 ° C.

Le solvant désextrait 38 récupéré contient moins de 15 mg/l de métaux lourds résiduels.The de-extracted solvent 38 recovered contains less than 15 mg / l of residual heavy metals.

La solution aqueuse d'extraction 52 présente la composition suivante :
[C1⁻] = 107 g/l   [Ca²⁺] = 38,1 g/l
[Na⁺] ≦ 1 g/l   [K⁺] ≦ 1 g/l
[Cd²⁺] = 530 mg/l   [Zn²⁺] = 26,3 g/l
[Pb²⁺] = 9,2 g/l   [Cr³⁺] = 71 mg/l
[Fe³⁺] ≦ 105 mg/l   [Mn²⁺] = 540 mg/l
[Mg²⁺] ≦ 1 g/l   [Ba²⁺] = 31 mg/lThe aqueous extraction solution 52 has the following composition:
[C1⁻] = 107 g / l [Ca²⁺] = 38.1 g / l
[Na⁺] ≦ 1 g / l [K⁺] ≦ 1 g / l
[Cd²⁺] = 530 mg / l [Zn²⁺] = 26.3 g / l
[Pb²⁺] = 9.2 g / l [Cr³⁺] = 71 mg / l
[Fe³⁺] ≦ 105 mg / l [Mn²⁺] = 540 mg / l
[Mg²⁺] ≦ 1 g / l [Ba²⁺] = 31 mg / l

Elle est précipitée par du carbonate de sodium et les eaux mères de lavage 60 récupérées après filtration contiennent moins de 15 mg/l de métaux lourds.It is precipitated by sodium carbonate and the mother liquors from washing 60 recovered after filtration contain less than 15 mg / l of heavy metals.

Exemple 2Example 2

Dans une installation analogue à celle qui vient d'être décrite, on traite un effluent d'une usine de traitement de surface qui présente la composition suivante :
[C1⁻] = 410 mg/l   [NH₄⁺] = 15 mg/l
[Na⁺] = 105 mg/l   [K⁺] = 30 mg/l
[CrVI] = 45 mg/l   [Zn²⁺] = 125 mg/l
[Fe³⁺] = 45 mg/l   [Cu²⁺] = 10 mg/l
[Co²⁺] = 5 mg/l   [Ni²⁺] = 10 mg/l
et divers autres éléments en moindre concentration, tels que Al et F. Le pH est égal à 1,8.In an installation similar to that which has just been described, an effluent from a surface treatment plant is treated which has the following composition:
[C1⁻] = 410 mg / l [NH₄⁺] = 15 mg / l
[Na⁺] = 105 mg / l [K⁺] = 30 mg / l
[Cr VI ] = 45 mg / l [Zn²⁺] = 125 mg / l
[Fe³⁺] = 45 mg / l [Cu²⁺] = 10 mg / l
[Co²⁺] = 5 mg / l [Ni²⁺] = 10 mg / l
and various other elements in lower concentration, such as Al and F. The pH is equal to 1.8.

On ajoute du métabisulfite de sodium à raison de 20 mg/l. La solution mère 36 et le solvant organique 38 sont introduits dans le premier appareil d'extraction 2 avec un débit de solvant égal à 0,2 fois le débit de phase aqueuse. On contrôle le pH à 5,5 par ajout de NaOH 1,0 N.Sodium metabisulfite is added at a rate of 20 mg / l. The mother solution 36 and the organic solvent 38 are introduced into the first extraction device 2 with a flow rate of solvent equal to 0.2 times the flow rate of aqueous phase. The pH is checked at 5.5 by adding 1.0 N NaOH.

Le solvant organique 38 titre 0,6 M/l d'acide di-(2-éthylhexyl)-manothiophosphorique dans le TPH.The organic solvent 38 titers 0.6 M / l of di- (2-ethylhexyl) -manothiophosphoric acid in TPH.

Le raffinat 46 présente la composition suivante :
[C1⁻] = 410 mg/l   [NH₄⁺] = 15 mg/l
[Na⁺] = 105 mg/l   [K⁺] = 30 mg/l
[Cr³⁺] ≦ 1 mg/l   [Zn²⁺] ≦ 1 mg/l
[Fe²⁺] ≦ 1 mg/l   [Cu²⁺] ≦ 1 mg/l
[Co²⁺] ≦ 1 mg/l   [Ni²⁺] ≦ 1 mg/lRaffinate 46 has the following composition:
[C1⁻] = 410 mg / l [NH₄⁺] = 15 mg / l
[Na⁺] = 105 mg / l [K⁺] = 30 mg / l
[Cr³⁺] ≦ 1 mg / l [Zn²⁺] ≦ 1 mg / l
[Fe²⁺] ≦ 1 mg / l [Cu²⁺] ≦ 1 mg / l
[Co²⁺] ≦ 1 mg / l [Ni²⁺] ≦ 1 mg / l

La solution organique chargée en métaux lourds 48 est traitée dans le deuxième appareil d'extraction 4, à contre-courant d'une solution d'acide chlorhydrique 3 N dont le débit volume est 5 fois plus faible que le débit de phase organique.The organic solution loaded with heavy metals 48 is treated in the second extraction device 4, against the flow of a 3N hydrochloric acid solution whose volume flow is 5 times lower than the flow of organic phase.

La première opération de d'extraction 2 est réalisée à une température moyenne de l'ordre de 22°C, tandis que la deuxième opération d'extraction 4 est réalisée à une température moyenne de 50°C.The first extraction operation 2 is carried out at an average temperature of the order of 22 ° C, while the second extraction operation 4 is carried out at an average temperature of 50 ° C.

Le solvant désextrait 38 récupéré contient moins de 15 mg/l de métaux lourds résiduels.The de-extracted solvent 38 recovered contains less than 15 mg / l of residual heavy metals.

La solution aqueuse d'extraction 52 présente la composition suivante :
[C1⁻] = 100 g/l   [NH⁴⁺] ≦ 1 mg/l
[Na⁺] ≦ 1 mg/l   [K⁺] ≦1 mg/l
[Cr³⁺] = 1,10 g/l   [Zn²⁺] = 3,15 g/l
[Fe²⁺] = 1,16 g/l   [Cu²⁺] = 243 mg/l
[Co²⁺] = 103 mg/l   [Ni²⁺] = 238 mg/lThe aqueous extraction solution 52 has the following composition:
[C1⁻] = 100 g / l [NH⁴⁺] ≦ 1 mg / l
[Na⁺] ≦ 1 mg / l [K⁺] ≦ 1 mg / l
[Cr³⁺] = 1.10 g / l [Zn²⁺] = 3.15 g / l
[Fe²⁺] = 1.16 g / l [Cu²⁺] = 243 mg / l
[Co²⁺] = 103 mg / l [Ni²⁺] = 238 mg / l

Elle est précipitée par du carbonate de sodium et les eaux mères de lavage 60 récupérées après filtration contiennent moins de 15 mg/l de métaux lourds.It is precipitated by sodium carbonate and the mother liquors from washing 60 recovered after filtration contain less than 15 mg / l of heavy metals.

Claims (18)

Procédé de traitement et de conditionnement d'effluents solides ou liquides chargés en métaux lourds, caractérisé en ce qu'il comprend les étapes consistant à : a) réduire chimiquement à l'aide d'un agent réducteur (32), l'effluent liquide (26) ou l'effluent solide (18) traité de façon à se présenter sous forme liquide, pour obtenir une solution mère (36) ; b) mettre, dans un premier appareil d'extraction (2), cette solution mère (36) en contact avec un solvant organique (38) contenant essentiellement un extractant organophosphoré et un hydrocarbure capable d'extraire sélectivement les métaux lourds, des anions et des métaux alcalins et alcalino-terreux ; c) mettre, dans un deuxième appareil d'extraction (4), la solution organique chargée en métaux lourds et issue du premier appareil d'extraction (2), en contact avec une solution aqueuse (50) capable d'extraire les métaux lourds de la phase organique ; d) mettre en contact, la solution aqueuse (52) issue du deuxième appareil d'extraction (4), avec un agent de précipitation (54) capable de précipiter la totalité des métaux lourds contenus dans la solution aqueuse (52) sous forme d'espèces chimiques insolubles et vitrifiables ; e) filtrer la suspension (56) obtenue et récupérer le filtrat (34) afin de le recycler avec la solution mère (36), puis laver le précipité solide (64) à l'eau afin de le séparer des eaux mères de lavage (60) ; et f) vitrifier le précipité lavé filtré (64). Process for treating and conditioning solid or liquid effluents loaded with heavy metals, characterized in that it comprises the steps consisting in: a) chemically reduce using a reducing agent (32), the liquid effluent (26) or the solid effluent (18) treated so as to be in liquid form, to obtain a mother solution (36) ; b) putting, in a first extraction device (2), this mother solution (36) in contact with an organic solvent (38) essentially containing an organophosphorus extractant and a hydrocarbon capable of selectively extracting heavy metals, anions and alkali and alkaline earth metals; c) putting, in a second extraction device (4), the organic solution loaded with heavy metals and coming from the first extraction device (2), in contact with an aqueous solution (50) capable of extracting the heavy metals organic phase; d) bringing the aqueous solution (52) from the second extraction device (4) into contact with a precipitation agent (54) capable of precipitating all of the heavy metals contained in the aqueous solution (52) in the form of 'insoluble and vitrifiable chemical species; e) filter the suspension (56) obtained and recover the filtrate (34) in order to recycle it with the mother solution (36), then wash the solid precipitate (64) with water in order to separate it from the mother liquors for washing ( 60); and f) vitrifying the filtered washed precipitate (64). Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que l'agent réducteur (32) est choisi parmi le bisulfite de sodium, le métabisulfite de sodium et le sulfate ferreux ou le dioxyde de soufre.Treatment and conditioning method according to claim 1, characterized in that the reducing agent (32) is chosen from sodium bisulfite, sodium metabisulfite and ferrous sulfate or sulfur dioxide. Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que l'extractant organophosphoré peut être choisi parmi l'acide bis-(2,4,4-trimethylpentyl)-monothiophosphinique ou l'acide di-(2-éthylhexyl)-monothiophosphorique, en présence de calcium dans la solution mère, ou parmi l'acide di-(2-éthylhexyl)-phosphorique, l'acide di-(2,4,4-trimethylpentyl)-phosphinique ou le mono(2-éthylhexyl) ester de l'acide (2-éthylhexyl)-phosphonique, en l'absence de calcium dans la solution mère (36).Treatment and conditioning process according to claim 1, characterized in that the organophosphorus extractant can be chosen from bis- (2,4,4-trimethylpentyl) -monothiophosphinic acid or di- (2-ethylhexyl) acid -monothiophosphoric, in the presence of calcium in the mother solution, or among di- (2-ethylhexyl) -phosphoric acid, di- (2,4,4-trimethylpentyl) -phosphinic acid or mono (2-ethylhexyl ) ester of (2-ethylhexyl) -phosphonic acid, in the absence of calcium in the mother solution (36). Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que l'hydrocarbure est le tétrapropylène hydrogéné (TPH).Treatment and conditioning process according to claim 1, characterized in that the hydrocarbon is hydrogenated tetrapropylene (TPH). Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que le solvant organique (38) est constitué par un mélange contenant 0,2 à 1,0 mole par litre d'extractant organophosphoré dilué dans l'hydrocarbure.Treatment and conditioning process according to claim 1, characterized in that the organic solvent (38) consists of a mixture containing 0.2 to 1.0 mole per liter of organophosphorus extractant diluted in the hydrocarbon. Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que le solvant organique (38) introduit dans le premier appareil d'extraction (2) est issu du deuxième appareil d'extraction (4).Treatment and conditioning method according to claim 1, characterized in that the organic solvent (38) introduced into the first extraction device (2) comes from the second extraction device (4). Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce qu'au moins l'un des appareils d'extraction (2, 4) est une colonne pulsée.Processing and conditioning method according to claim 1, characterized in that at least one of the extraction devices (2, 4) is a pulsed column. Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que le traitement réalisé dans le premier appareil d'extraction (2) est effectué à un pH compris entre 4,5 et 6,5 environ.Treatment and conditioning method according to claim 1, characterized in that the treatment carried out in the first extraction apparatus (2) is carried out at a pH between approximately 4.5 and 6.5. Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que le traitement réalisé dans le premier appareil d'extraction (2) est effectué à une température comprise entre 20 à 25°C environ.Treatment and conditioning method according to claim 1, characterized in that the treatment carried out in the first extraction apparatus (2) is carried out at a temperature between 20 to 25 ° C approximately. Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que le traitement réalisé dans le deuxième appareil d'extraction (4) est effectué à une température comprise entre 40 et 60°C environ.Treatment and conditioning method according to claim 1, characterized in that the treatment carried out in the second extraction device (4) is carried out at a temperature between 40 and 60 ° C approximately. Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que le traitement de précipitation est effectué à une température comprise entre 40 et 60°C environ.Treatment and conditioning method according to claim 1, characterized in that the precipitation treatment is carried out at a temperature of between 40 and 60 ° C approximately. Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que l'agent de précipitation (54) est du carbonate de sodium ou du carbonate de calcium.Treatment and conditioning method according to claim 1, characterized in that the precipitation agent (54) is sodium carbonate or calcium carbonate. Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que la solution aqueuse (50) introduite dans le deuxième appareil d'extraction (4) est obtenue à partir des eaux mères de lavage (60) issues de la filtration (8) et ajustée en continu par une solution d'acide chlorhydrique (62) de façon à contenir entre 0,1 et 6,0 mol/l d'acide chlorhydrique.Treatment and conditioning method according to claim 1, characterized in that the aqueous solution (50) introduced into the second extraction device (4) is obtained from the mother liquors of washing (60) from the filtration (8 ) and continuously adjusted with a hydrochloric acid solution (62) so as to contain between 0.1 and 6.0 mol / l of hydrochloric acid. Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que le raffinat (46) issu du premier appareil d'extraction (2) est concentré de façon à former des sels (70) et une phase aqueuse (68).Treatment and conditioning method according to claim 1, characterized in that the raffinate (46) from the first device extraction (2) is concentrated so as to form salts (70) and an aqueous phase (68). Procédé de traitement et de conditionnement selon la revendication 1, caractérisé en ce que le traitement de l'effluent solide (18) de façon à le rendre liquide est effectué : - en mettant dans un dispositif de lixiviation (14) l'effluent solide à traiter (18) en contact avec une solution de lixiviation (28) et un acide minéral (20) dilué avec une solution aqueuse et capable de solubiliser la fraction soluble de l'effluent solide (18), pour former une suspension (22) ; - en introduisant cette suspension (22) dans un dispositif de filtration (16), afin de la séparer en un solide résiduel insoluble (30) et en un effluent liquide (26) à introduire dans le premier appareil d'extraction (2) ; et - en lavant le solide résiduel insoluble obtenu par de l'eau (24). Treatment and conditioning method according to claim 1, characterized in that the treatment of the solid effluent (18) so as to make it liquid is carried out: - by putting in a leaching device (14) the solid effluent to be treated (18) in contact with a leaching solution (28) and a mineral acid (20) diluted with an aqueous solution and capable of dissolving the soluble fraction of the solid effluent (18), to form a suspension (22); - by introducing this suspension (22) into a filtration device (16), in order to separate it into an insoluble residual solid (30) and into a liquid effluent (26) to be introduced into the first extraction device (2); and - washing the insoluble residual solid obtained with water (24). Procédé de traitement et de conditionnement selon la revendication 15, caractérisé en ce que le traitement de lixiviation est effectué à une température comprise entre 40 et 80°C environ.Treatment and conditioning method according to claim 15, characterized in that the leaching treatment is carried out at a temperature of between 40 and 80 ° C approximately. Procédé de traitement et de conditionnement selon la revendication 15, caractérisé en ce que la solution de lixiviation (28) est constituée par l'eau mère de lavage issue du dispositif de filtration (16), additionnée d'acide chlorhydrique de façon à ajuster le pH de la suspension à une valeur comprise 0,5 et 3,0 environ.Treatment and conditioning method according to claim 15, characterized in that the leaching solution (28) consists of the mother liquor from the filtration device (16), added with hydrochloric acid so as to adjust the pH of the suspension at a value of approximately 0.5 and 3.0. Procédé de traitement et de conditionnement selon la revendication 15, caractérisé en ce que la quantité d'eau de lavage (24) mise en oeuvre dans le dispositif de filtration (16) est telle qu'après recyclage dans le dispositif de lixiviation (14), la suspension (22) obtenue contienne entre 5 et 20 % en poids de matière solide.Treatment and conditioning method according to claim 15, characterized in that the quantity of washing water (24) used in the filtration device (16) is such that after recycling in the leaching device (14), the suspension (22) obtained contains between 5 and 20% by weight of solid material.
EP19950401367 1994-06-15 1995-06-13 Process for the treatment and conditioning of solid or liquid effluents charged with heavy metals Expired - Lifetime EP0687483B1 (en)

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Publication number Priority date Publication date Assignee Title
FR2760662A1 (en) * 1997-03-11 1998-09-18 Recupyl Sa PROCESS FOR THE TREATMENT OF ASBESTOS BY THERMOCHEMICAL CONVERSION
FR2760663A1 (en) * 1997-03-11 1998-09-18 Recupyl Sa Treating incinerated domestic and industrial waste
WO1999021619A1 (en) * 1997-10-24 1999-05-06 Recupyl S.A. Method for treating household refuse incinerator ash

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FR2801521B1 (en) * 1999-11-29 2002-04-26 Commissariat Energie Atomique PROCESS AND DEVICE FOR TREATING AND CONDITIONING AN EFFLUENT FOR VITRIFICATION

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US4873065A (en) 1986-05-02 1989-10-10 Kernforschungszentrum Karlsruhe Gmbh Flue gas purification process
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2760662A1 (en) * 1997-03-11 1998-09-18 Recupyl Sa PROCESS FOR THE TREATMENT OF ASBESTOS BY THERMOCHEMICAL CONVERSION
FR2760663A1 (en) * 1997-03-11 1998-09-18 Recupyl Sa Treating incinerated domestic and industrial waste
WO1999021619A1 (en) * 1997-10-24 1999-05-06 Recupyl S.A. Method for treating household refuse incinerator ash

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FR2721237A1 (en) 1995-12-22
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EP0687483B1 (en) 1998-08-26
FR2721237B1 (en) 1996-08-02

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