Classifications

• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
  • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
  • G21F9/001—Decontamination of contaminated objects, apparatus, clothes, food; Preventing contamination thereof
  • G21F9/002—Decontamination of the surface of objects with chemical or electrochemical processes
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D1/00—Detergent compositions based essentially on surface-active compounds; Use of these compounds as a detergent
  • C11D1/66—Non-ionic compounds
  • C11D1/72—Ethers of polyoxyalkylene glycols
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D17/00—Detergent materials or soaps characterised by their shape or physical properties
  • C11D17/0008—Detergent materials or soaps characterised by their shape or physical properties aqueous liquid non soap compositions
  • C11D17/003—Colloidal solutions, e.g. gels; Thixotropic solutions or pastes
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
  • C23G1/14—Cleaning or pickling metallic material with solutions or molten salts with alkaline solutions
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
  • C11D2111/10—Objects to be cleaned
  • C11D2111/14—Hard surfaces
  • C11D2111/16—Metals
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
  • C11D2111/10—Objects to be cleaned
  • C11D2111/14—Hard surfaces
  • C11D2111/20—Industrial or commercial equipment, e.g. reactors, tubes or engines

Definitions

• the invention relates to a degreasing composition, as well as to a degreasing gel and foam which comprise said composition.
• the invention also relates to a method for degreasing and / or decontaminating a surface using said composition, said gel and / or said degreasing foam.
• the present invention finds for example, but is not limited to, an application in the degreasing of surfaces, in particular of metallic surfaces such as apparatuses, components, grounds, etc. of a factory for reprocessing of irradiated nuclear fuels.
• These surfaces are, or may be, in contact with one or more fatty substances which may be contaminated. It is therefore necessary to regularly clean these surfaces for the purpose of sanitation and / or radioactive decontamination.
• one of these substances is a solvent called tributylphosphate (TBP) which is used in cycles of extraction of radioactive metals such as for example uranium and plutonium.
• TBP tributylphosphate
• this solvent acquires a particularly significant radiochemical activity, since it can contain up to a few tens of grams of uranium and / or plutonium per liter.
• This solvent can then become a high activity solvent (HA solvent) or a very high activity solvent (THA solvent).
• HA solvent high activity solvent
• THA solvent very high activity solvent
• the presence of these HA and THA solvents on some of the components of factories, for reprocessing irradiated fuels such as decanter mixers, extraction columns, etc. often leads to the formation of particularly organophilic metal surfaces which promote fatty deposits. later. These fatty deposits are almost insensitive to rinsing with conventional aqueous solutions used in reprocessing and therefore require specific treatment.
• degradation products of TBP obtained by radiolysis of the solvent for example hydrogenodibutylphosphate (HDBP) form precipitates with most of the metal cations such as iron III, thorium IV, uranium IV, plutonium IV, 1 europium III, neodymium III, zirconium IV, etc ... which may be present during the reprocessing of nuclear waste, and in particular of irradiated fuels.
• metals are often deposited on the surfaces of the components of reprocessing plants in contact with them, in the form of colloids. Decontamination of these surfaces requires their erosion to a thickness of 2 to 10 ⁇ m to be able to eliminate all traces of radiochemical activity. This erosion can only be effective after removal of the fatty solvent covering these surfaces. It is therefore necessary to decontaminate these surfaces to have recourse beforehand to suitable degreasing products and processes.
• composition, the gel and the foam as well as the degreasing and / or decontamination process which are the subject of the present invention constitute means effective degreasing and / or decontamination of these surfaces.
• the invention is logically not limited to the aforementioned applications, and it finds an application in all fields where rapid and effective degreasing of an installation is necessary. Examples of these applications will be given below in the description of the invention.
• nitric acid does not make it possible to completely dissolve the precipitates formed on surfaces which are still greasy, in particular the precipitates composed of metallic dibutyl phosphate.
• results of radioactivity analysis of the rinsing solutions show that there is no significant radioactivity peak reflecting an efficient and rapid rinsing, but a slightly higher radioactivity after two to three sequences of rinsing and then tending towards a limit, with a higher activity when the rinsing solutions are renewed.
• the rinsing solutions are used in large quantities, up to five to ten times the volume of an apparatus to be degreased, and at a very high concentration, of the order of 3 to 10 mol. .l -1 .
• This technique although commonly used, therefore leads to a significant increase in waste from reprocessing of spent nuclear fuel.
• the object of the present invention is precisely to provide a composition, a liquid, a gel and a degreasing foam which allow an efficient and rapid degreasing of a surface, and a reduction in the volume of effluents formed by compared to the techniques of the prior art.
• the surfaces concerned can be any type of surface resistant to the degreasing composition according to the invention, for example a metallic surface, a glass surface, a plastic surface, a concrete surface, etc.
• the metal surface can for example be a steel surface, an austenitic steel surface, a uranus, aluminum, zirconium surface, etc. ..
• a fatty substance which can be a fatty solvent such as TBP, HDBP, H 2 MBP, TPH, or a mixture of these solvents, various oils such as edible oils, oils lubrication, etc ...
• the degreasing composition according to the invention is characterized in that it comprises a base, a fatty alcohol, saturated or unsaturated, polyethoxylated, a copoly era of ethylene oxide and propylene oxide and water.
• the base can be for example sodium hydroxide, or an equivalent base such as alcoholic potash, sodium or potassium carbonate, etc.
• the base can for example have a concentration of OH " ions chosen from a range from 0.1 to 1.5 mol.l -1 in said composition.
• the polyethoxylated fatty alcohol can be a compound of general formula:
• R is a long-saturated or unsaturated carbon-containing alkyl comprising from 10 to 24 carbon atoms, and in which n represents the number of monomeric ethylene oxide units, n being able to vary from 10 to 30.
• the fatty alcohol can be for example lauric alcohol, myristic alcohol, ketic alcohol, stearic alcohol, peanut alcohol, palmitic alcohol, oleic alcohol, and linoleic alcohol, or a mixture thereof.
• n can for example be equal to 10 or 20.
• the polyethoxylated fatty alcohol can be, for example, an oleic alcohol ether and a polyethylene oxide containing 20 monomeric units of ethylene oxide.
• the fatty alcohol, saturated or unsaturated, polyethoxylated may be at a concentration chosen from a range ranging from about 0.01 to 1.5% by weight, or alternatively at a concentration chosen from a range from approximately 0.05 to 0.8% by weight in said composition, or alternatively at a concentration chosen from a range ranging from approximately 0.05 to 0.4% by weight in the composition depending on the use of the composition according to the invention for making a liquid, a foam or a degreasing gel.
• the copolymer of ethylene oxide and propylene oxide can for example be a block copolymer. It can comprise monomeric units of the ethylene oxide type and monomeric units of the propylene oxide type, respectively denoted below by OE and OP. This copolymer will then have the following formula (I):
• the copolymer of ethylene oxide and propylene oxide can be at a concentration chosen from a range ranging from approximately 0.025 to approximately 1.5% by weight, or alternatively at a concentration chosen from a range from about 0.025 to about 0.6% by weight, or in a range from about 0.025 to 0.4% by weight, or even in a range from about 0.4 to 1.5% by weight according to the use of the composition according to the invention for making a liquid, a foam or a degreasing gel.
• the base may be sodium hydroxide
• the fatty alcohol, saturated or unsaturated, polyethoxylated may be a polyethoxylated oleic alcohol comprising 10 or 20 units of ethylene oxide, for example 20 units
• the oxide copolymer ethylene and propylene oxide can be a block copolymer with 45 monomeric units of ethylene oxide and 9 monomeric units of propylene oxide.
• the composition according to the invention may also comprise a foam-inhibiting agent when it is used in liquid form, hereinafter also called degreasing liquid, or in the form of a gel.
• This inhibiting agent has the role of preventing the formation of foam when the composition according to the invention is used in liquid form or in gel form.
• This inhibiting agent can be, for example, a branched or unbranched alkyl phosphate.
• the alkyl phosphate in the liquid or the degreasing gel according to the invention also makes it possible to increase the capacity to micellize, by for example TBP, by the two other surfactants.
• the alkyl phosphate can be branched, it can contain.
• the foam inhibiting agent chosen is an alkyl phosphate containing from 6 to 10 carbon atoms
• it may for example be at a concentration chosen from a range going from approximately 0.1 to approximately 0 , 4% by weight in the composition. This concentration is for example favorable for a concentration of OH- ions ranging for example from about 0.5 to about 1 mol.l -1 .
• the composition described above can be in concentrated form, for example for storage.
• this concentrated composition when this concentrated composition is to be used, it can be used as it is or be diluted with water to form a composition having concentrations of each of the constituents of this composition required for effective degreasing of a surface.
• the present invention relates in particular to a degreasing liquid comprising a composition according to the invention, which can comprise approximately 0.05 to approximately 0.4% by weight of polyethoxylated fatty alcohol, approximately 0.025 to approximately 0.6% by weight of copolymer of ethylene oxide and propylene oxide, and may also comprise a foam-inhibiting agent such as that described above.
• This foam-inhibiting agent for example in the case of a branched alkyl phosphate containing from 6 to 12 carbon atoms, can be at a concentration of approximately 0.1 to approximately 0.4% by weight. in the degreasing liquid according to the invention.
• the present invention also relates to a degreasing foam comprising a gas phase and a degreasing composition according to the invention, and which can also comprise a foam destabilizing agent.
• the gas phase may for example be air, for example a neutral gas such as argon, or any gas making it possible to form a foam with the composition according to the invention.
• the foam can be formed by various means such as mechanical agitation, generation through a porous lining, etc.
• a degreasing composition favorable for forming a foam can comprise a fatty, saturated or unsaturated, polyethoxylated alcohol which can be a concentration chosen from a range going from approximately 0.4 to approximately 1.5% by weight, a copolymer of etylene oxide and propylene oxide which may be at a concentration selected from a range from about 0.4 to about 1.5% by weight, and may further comprise a foam destabilizing agent .
• the foam destabilizing agent can be any of the foam destabilizing agents known to a person skilled in the art, for example a compound chosen from those described above as being foam inhibitors.
• the foam destabilizing agent can be an alkyl phosphate, branched or not, comprising from 4 to 12 carbon atoms, or also from 6 to 10 carbon atoms and which can be mono- or polydispersed.
• the foam destabilizing agent chosen is a branched alkyl phosphate containing from 6 to 10 carbon atoms, it can be at a concentration of 0.2 to 1.1% by weight in the composition according to the invention, for a weight ratio, in the composition, of the concentration of saturated fatty alcohol . or unsaturated, polyethoxylated on the concentration of the copolymer of ethylene oxide and propylene oxide equal to approximately 1.5.
• the invention also relates to a degreasing gel comprising a degreasing composition according to the invention, and further comprising a viscosity agent.
• the degreasing gel can comprise the degreasing composition according to the invention in which the fatty alcohol, saturated or unsaturated, polyethoxylated can be at a concentration chosen in a range going from approximately 0.05 to approximately 1 % by weight or in a range from about 0.05 to about 0.4% by weight, and in which the ethylene oxide copolymer can be at a concentration chosen from a range from about 0.025 to about 0.4% by weight, and further comprising a viscosifier.
• This viscosifying agent may for example be a compound chosen from a group comprising xanthan gum, an alumina oxide or a silica gel.
• the viscosifying agent chosen is xanthan gum
• it can be at a concentration chosen from a range going from 0.5 to around 5% by weight in said composition, for example at a concentration of around 1.2% by weight.
• the invention therefore relates in particular to a composition, a liquid, a foam, and a gel comprising said composition.
• These different formulations that is to say liquid, foam and gel, allow rapid and effective degreasing of a surface such as those mentioned above. It has been found that the present invention allows in particular a reduction in the quantity of effluents from degreasing and a reduction in the Na + concentration of these effluents compared to the prior art, and consequently, a reduction in waste. from this degreasing, for better degreasing efficiency.
• the degreasing efficiency of the present invention is due in particular to the nature of the various constituents of this composition and to their concentration.
• the composition according to the invention comprises a base.
• This base makes it possible to form a basic aqueous solution which facilitates the degreasing of a surface as well as a transfer of the fatty substance coming from these surfaces in the aqueous solution in the form of an emulsion.
• the degreasing efficiency of the composition is in particular a function of the alkalinity of this aqueous solution.
• the base used can be at an OH- concentration chosen from a range from 0.1 to 1.5 mol.l -1 .
• the composition of the invention therefore makes it possible to save a factor of up to 10 Na + ions for the same number of rinsing sequences applied to a surface to be degreased and for better efficiency.
• the base can also be a base equivalent to sodium hydroxide, for example sodium carbonate.
• the composition according to the invention also comprises a fatty alcohol, saturated or unsaturated, polyethoxylated.
• This polyethoxylated fatty alcohol is a nonionic surfactant comprising a lipophilic chain formed by fatty alcohol and a polar head formed by polyethoxylated.
• the lipophilic chain allows the composition of the invention to ensure optimal detergency and a dispersion of fatty substances, or lipophilic organic constituents, in the basic aqueous solution.
• the polar head ensures solubility in the alkaline aqueous phase.
• the polyethoxylated fatty alcohol of the composition according to the invention may consist of an oleic alcohol and of a polyethylene oxide composed of a chain of twenty monomeric units of ethylene oxide as represented by the following formula (II): (II)
• This polyethoxylated fatty alcohol can be for example SIMULSOL 98 or SIMULSOL 96 (trademarks) manufactured by the company SEPPIC.
• This polyethoxylated fatty alcohol forms micelles which are spherical particles with a diameter of 50 to 150 nm comprising a polar external face in contact with the basic aqueous solution and an apolar internal face in contact with the fatty substances. .
• the fatty substances are retained inside these micelles and dispersed with them in the basic aqueous solution. The result of this retention and this dispersion is a dissolution of the fats in the basic aqueous solution.
• the composition according to the invention also comprises an alkylene oxide polymer. This polymer is a nonionic surfactant.
• an alkylene oxide polymer suitable for the composition according to the invention may be a block copolymer with 45 ethylene oxides and 9 propylene oxides as represented by the following formula (III):
• This copolymer has a molar mass of
• HLB hydrophilic lipophilic balance
• the alkylene oxide polymer may for example be SYNTHIONIC P8020 (trademark) manufactured by the company ITCO, or PLURONIC PE
• the composition according to the invention may also comprise a foam-inhibiting agent.
• the composition according to the invention comprises a surfactant which can under certain conditions cause foaming. This foam can be troublesome, for example in a degreasing process using an aero-ejector or air lift.
• This inhibiting agent can for example be an alkyl phosphate comprising from 4 to 12 carbon atoms as represented by the following formula (III):
• This inhibiting agent makes it possible to increase the drainage speed of the interstitial liquid contained in a foam in formation, and therefore to limit or prevent this formation. It also makes it possible to improve the wetting power of the composition and can play an important role in the retention of the fatty substance (s) in the micelles. It therefore also makes it possible, as previously emphasized, to increase the ability to micellize, for example TBP, with the two surfactants of the composition according to the invention.
• alkyl phosphate are MONTALINE ANP and SEPPIC 619NP (trademarks) manufactured by the company SEPPIC. It acts as a dispersant and allows, for example, to keep in suspension precipitates of dibutylphosphates of Pu, Am, U and Zr which are produced by the extraction of the solvent in an alkaline medium.
• the composition according to the invention may also comprise a foam destabilizing agent.
• This agent destabilizer may be the same as the above-mentioned foam-inhibiting agent, but in this case it will make it possible to control the stability of the foam formed, that is to say the time necessary for a total transformation of a given volume of this foam in liquid and gas. This time, or lifetime, can be modified by modifying the concentration of this destabilizing agent in the composition according to the invention.
• This destabilizing agent facilitates the drainage of the interstitial liquid in the foam.
• the concentration of destabilizing agent is chosen to obtain a life of the foam of 10 to 30 minutes.
• a lifetime can be adapted for example to fill a container with a given volume in an acceptable time and to have a foam having a sufficient drainage rate so that the composition according to the invention can degrease the surface of this container.
• the foam when the foam has filled the container, it produces, if its lifespan is suitably chosen, a drainage liquid which, by running down the walls of the container, dissolves the fatty substance, for example TBP and its derivatives, and l results in the form of micelles.
• the drainage liquid, loaded with these micelles can then be recovered in a lower part of the container, and can be recycled.
• the composition according to the invention can also comprise a viscosifying agent.
• This viscosifying agent allows, for example, a controlled local application of the gel formed comprising the composition according to the invention for degreasing a surface accessible to an operator.
• An example of a viscosity agent that can be added to the composition according to the invention is xanthan gum. It is a polysaccharide comprising a chain of 16 molecules, 13 of which are linear and three branched and its molecular weight is several millions. It allows the formation of non-Newtonian gels which resist heat and pH variations well.
• degreasing a surface consists in particular in dissolving in the aqueous solution the substance (s) present on the surface to be degreased in the form of micelles.
• micelles are formed in particular with fatty alcohol, saturated or unsaturated, polyethoxylated and contain the
• the micelles are dynamic particles that constantly form and disintegrate in the solution.
• the concentration of one of the constituents of the composition according to the invention is too low, in particular relative to the quantity of fatty substance (s) to be dissolved, the micelles can dissociate and release the substance (s) ( s) oily (s) which then redeposit (s) on degreased surfaces.
• the dissociation of the micelles is visible and results in the formation of a cloud in the solution. This dissociation can occur when the composition according to the invention is saturated with fatty substance (s), and / or from a certain temperature.
• the saturation of the composition according to the invention with a fatty substance can be measured by measuring the "cloud point" of this composition.
• the cloud point is expressed in degrees Celsius (° C).
• the nonionic surfactant cloud point polyoxyethylenic corresponds to a partial dehydration of the hydrophilic chain, and which results, if the temperature of the cloud point is reached, in the phase separation, that is to say the demixing of the surfactant.
• the cloud point of the composition it is preferable for the cloud point of the composition to be higher than room temperature, that is to say about 20 ° C., when the degreasing is carried out at room temperature or at a temperature higher than this.
• a high cloud point also indicates a high capacity for dissolving a fatty substance. The measurement of the cloud point therefore makes it possible in particular to measure the degreasing efficiency of the composition according to the invention. This degreasing efficiency can also be measured by measuring the wettability of this surface.
• the degreasing efficiency of a surface by the composition according to the invention is therefore due in particular to the nature of the constituents of this composition. This efficiency is also due to the concentrations of its various constituents.
• the concentration of each of the constituents of the composition according to the invention can be adjusted, from the concentration ranges described above, in particular depending on the nature and the amount of fatty substance (s) present on the surface to be degreased, the surface to be degreased, the liquid, foam or gel formulation used, and the temperature at which the degreasing is carried out.
• the composition according to the invention comprises sodium hydroxide or an equivalent base, an ether of oleic alcohol and of a polyethylene oxide comprising twenty units of ethylene oxide, and a block copolymer containing 45 units of ethylene oxides and 9 units of propylene oxides hereinafter called block copolymer.
• the above composition is used to form a degreasing liquid. It may be desirable to adjust the concentrations of each of the above components so that this liquid has low foaming.
• a degreasing liquid comprising from about 0.5 to about 1 mol.l -1 of NaOH, from about 0.05 to about 0.4% by weight of polyethoxylated oleic alcohol, preferably d '' from about 0.05 to about 0.2% of this alcohol, and from about 0.025 to about 0.4% by weight of the block copolymer, or from about 0.1 to about 0.4% by weight, or still from about 0.2 to about 0.4% by weight of this copolymer is a low foaming composition.
• the liquid may further comprise a foam inhibiting agent.
• the composition according to the invention has a cloud point greater than room temperature, approximately equal to 38 ° C, and even greater than 40 ° C.
• a decrease in the concentration of polyethoxylated fatty alcohol or block copolymer can make it possible to increase this cloud point.
• Such a composition allows, for example, an effective degreasing of a metal blade covered with approximately 1 mg / cm 2 of a mixture comprising TBP and its derivatives HDBP and H 2 MBP, or of a mixture comprising TPH, TBP and its derivatives HDBP and H 2 MBP in a period ranging from approximately 15 to approximately 200 min, without stirring, and at a temperature of 20 ° C.
• the degreased blade may indeed have a surface tension cos ⁇ tends towards 0, which translates an almost total or total degreasing of the surface.
• this formulation may become foaming when the NaOH concentration is less than or equal to about 0.5 mol.l -1 .
• the composition can then be adjusted and may further comprise a foam inhibiting agent. This is the case, for example, for use in a degreasing process using agitation or transport of this liquid composition by means of an air lift or air lift ("airlift"). Indeed, the pressure and the agitation undergone by the liquid in such a process requires a composition having low foamability.
• the foam-inhibiting agent can for example be an alkyl phosphate such as that mentioned above, at a concentration which can range from approximately 0.1 to approximately 0.4% by weight, or alternatively from approximately 0.3 to about 0.4% by weight in the composition.
• this inhibiting agent is added to the composition, in order to conserve and possibly improve the degreasing power of the composition, it may be necessary to increase the ether concentration of oleic alcohol and of polyoxyethylene glycol to approximately 0.3% in weight. Too much of the latter, and of the alkyl phosphate in the composition can however decrease the amount of fatty substance (s) which can be retained in the micelles. The concentration of block polymer can then be adjusted to one.
• a composition comprising approximately 0.2% by weight of 1 ether of oleic alcohol and of polyoxyethylene glycol, approximately 0.35% of block copolymer, approximately 0.5 to 1 mol.l -1 of NaOH, preferably about 0.5 mol.l -1 of NaOH, and about 0.4% by weight of alkyl phosphate has a cloud point of 68 ° C.
• This composition is a weakly foaming composition which allows, for example, a dissolution of approximately 3 g / l of TBP and its derivatives, and a degreasing of a surface comprising 1 mg / cm 2 of TBP and its derivatives in approximately 20 min.
• This weakly foaming composition is compatible for transport by means of an air lift.
• the inventors have noticed that the cloud point of the composition varies linearly from approximately 71 to approximately 20 ° C. with the sodium hydroxide concentration in a range ranging respectively from approximately 0.1 to approximately 1, 45 mol.l -1 of NaOH in particular in a natural convective regime, that is to say without agitation of the solution of the composition during the degreasing.
• composition of this embodiment is used in the form of foam.
• the preparation of a foaming solution from the composition according to the invention can be carried out for example with an ether concentration of oleic alcohol and of polyoxyethylene glycol from approximately 0.4% to approximately 1.5% by weight. , for example about 0.4 to about 1% by weight, for example with a sodium hydroxide concentration ranging from 0.5 to 1.5 mol.l -1 .
• the ether concentration of oleic alcohol and polyoxyethylene glycol can be from about 0.35 to about 0.60% by weight.
• This composition is suitable for example for generating a foam from a foam generator comprising a porous lining.
• This foam generator can for example be composed of a cylinder 120 mm long and 8 mm in diameter filled with 3.24 g of a packing of FORAFLON type (trademark).
• the foam can be generated for example with a flow rate of a solution of this composition ranging from approximately 23 to approximately 28 l / h, and a gas flow rate, for example air, of approximately 88 l / h in normal temperature and pressure conditions.
• the foam can be easily generated in this example at a flow rate ranging from approximately 120 to approximately 130 l / h.
• This foam may have an abundance, that is to say a ratio of the volume of foam generated on the volume of interstitial liquid ranging from approximately 6 to approximately 7.
• This foam is suitable for example for easily dissolving 1.2 g / 1 of TBP and its derivatives.
• the ratio of the gas flow rate to the liquid flow rate can be approximately 6 to 7 for generating a foam from a composition according to the invention and from a gas.
• a foam destabilizer can for example be an alkyl phosphate such as that described above, at a concentration ranging from approximately 0.2 to approximately 1.1% by weight in the composition, for example, when the composition comprises a ratio weight of fatty alcohol, saturated or unsaturated, polyethoxylated on the concentration of the copolymer of ethylene and propylene oxides equal to approximately 1.5 (that is to say a molar ratio approximately equal to 3.3).
• the alkyl phosphate can be approximately equal to 0.3% by weight.
• the alkyl phosphate can be at a concentration of about 0.3 to about 0.5% by weight, and when the soda has a concentration of less than 0.5 mol.l -1 , the alkyl phosphate can be at a concentration of approximately 1% by weight.
• This composition is particularly effective for degreasing, for example, a metal surface on which there is TBP and its derivatives.
• This latter composition makes it possible, for example, to form a foam at a flow rate of approximately 1.6 m 3 / h for a flow rate of an aqueous solution of this composition of approximately 200 l / h and a flow rate of gas, for example d 'air, about 1200 1 / h in a foam generator with a volume of 77 cm 3 and a diameter of 2.4 cm comprising 29 g of porous lining type FLORAFLON (trademark).
• the foam formed can have a lifetime, with the abovementioned concentrations, ranging from approximately 10 to approximately 30 minutes. Following these concentrations, the composition according to the invention can make it possible to dissolve up to 4 g / 1 of TBP and its derivatives.
• the flow rate of foam and its expansion can be increased when the concentration of alkyl phosphate increases from 0.3 to 0.4% by weight in this composition.
• the composition is used in the form of a gel.
• the composition according to the invention can comprise, for example, from approximately 0.05 to approximately 1% by weight or alternatively from approximately 0.05 to approximately 0.4% by weight of oleic alcohol ether. and polyethylene oxide, from about 0.025 to about 0.4% by weight of block copolymer, a foam inhibitor and a viscosity agent.
• the viscosity agent can be xanthan gum. This viscosifying agent can be added in an amount making it possible to obtain a gel having for example a viscosity of approximately 0.8 Pa.s (800 cps).
• the viscosifier is xanthan gum
• it can for example be added at a concentration of approximately 1.2% by weight.
• a low-foaming or weakly foaming composition such as those described in the first variant of this embodiment of the present invention, that is to say comprising a foam inhibitor.
• the degreasing of a surface comprising TBP and its derivatives is not altered, but it can lead to a three-phase solution which can cause a redeposition of the TBP.
• An augmentation of the concentration of oleic alcohol ether and polyoxyethylene glycol and in block copolymer, for example from 5 to 10 times the concentrations mentioned above, can make it possible under these conditions to obtain a monophasic system, that is to say having a optimal degreasing efficiency.
• the concentrations of each of the constituents in each of the variants of the aforementioned embodiment can be modified depending on the nature and the amount of fatty substance (s) to be dissolved for degreasing. of a surface, and so as to minimize the volume of degreasing effluents.
• the above concentrations are suitable, for example, for degreasing surfaces containing TBP, TPH, HDBP and H 2 MBP.
• composition, gel and foam which are the subject of the present invention make it possible to degrease a surface covered with a fatty substance with which they are brought into contact.
• This contacting can be carried out by any contacting means making it possible to apply a liquid, a foam or a gel to a surface to be degreased or cleaned.
• the contacting means is preferably chosen as a function of the surface to be degreased, and so as to minimize the effluents from degreasing.
• the contacting of the liquid with the surface to be degreased can be carried out for example by soaking, with or without stirring, by spraying, with or without pressure, or by release.
• Soaking can be used by example for degreasing surfaces of small objects or sealed containers
• sprinkling can be used to degrease, for example, larger areas, and circulation for example for pipes.
• the liquid formulation of the composition according to the invention can make it possible, for example, to use transport by an air lift (“airlift”) for degreasing the pipes by putting this formulation into circulation in these pipes.
• the contacting can be done for example by soaking or by circulation.
• the soaking can be used for example to degrease containers and more generally large structures, and the circulation can be used for example for large volume pipe networks of an installation having for example a complex internal geometry.
• the foam formulation makes it possible to considerably reduce the volume of effluents formed in a degreasing process.
• the contacting can be carried out by applying the gel to the surface to be degreased, for example by means of a roller, a cloth, a spatula. , or a sponge.
• This application can be used for example to degrease a surface accessible to an operator such as an external surface of an installation, a floor, a retention tank or a cell floor in a facility for reprocessing irradiated fuels.
• the composition used in the form of a gel can allow more localized contact on a surface to be degreased than the liquid or foam.
• the contacting can be carried out at any temperature suitable for degreasing a surface with the composition according to the invention.
• This temperature can be chosen according to the liquid, foam or gel formulation used, and according to the surface to be degreased. The choice of this temperature naturally depends on the cloud point of the composition used. In fact, a temperature above the cloud point of the composition causes the micelles to separate from the aqueous solution by entraining a portion of the surfactants and of the TBP associated with them. The solution becomes two-phase.
• this temperature can for example be room temperature, or a temperature above room temperature and below the cloud point of the composition.
• the composition is brought into contact with the surface to be degreased can be carried out for a period which can in particular be a function of the nature and the amount of fatty substance (s) present on the surface. surface to be degreased, the concentration of each of the constituents of the composition according to the invention, the liquid, foam or gel formulation used, the contacting means used, and the contacting temperature. This duration can be very short and reach 15 to 20 minutes for soaking the surface to be degreased, without stirring and at room temperature.
• the present invention therefore also relates to a method for degreasing a surface, said method comprising bringing the surface to be degreased into contact with a composition, a liquid, a foam, or a gel according to the invention.
• This method is applicable for degreasing surfaces such as those described above, and makes it possible to eliminate one (or more) fatty substance (s) such as that (s) described above.
• the contacting can be carried out under the conditions described above and with concentrations of each of the constituents of the composition, of the foam or of the gel as described above.
• This contacting can be repeated one or more times, renewing or not with each contacting the composition, the foam or the gel used.
• This contacting can be preceded and / or followed by a treatment, for example in a highly concentrated acid medium, for example HN0 3 in the case of a surface comprising TPH, TBP or its derivatives, in particular in a reprocessing plant. of spent fuel.
• a treatment for example in a highly concentrated acid medium, for example HN0 3 in the case of a surface comprising TPH, TBP or its derivatives, in particular in a reprocessing plant. of spent fuel.
• the surface can then be rinsed, for example with water and then dried.
• This process makes it possible, for example, to degrease workshop surfaces of nuclear fuel reprocessing plants using in particular solvents such as TBP and its derivatives as solvent for extracting fuels.
• the method of the invention is an effective means of degreasing these surfaces and has many advantages over the prior art.
• composition and the method of the invention make it possible to significantly reduce the volume of degreasing effluents, and in the example of a composition according to the invention comprising soda, their sodium concentration, and therefore to reduce the number of bitumen drums compared to the prior art.
• the composition according to the invention makes possible the concentration of TBP and of its derivatives dissolved and retained in the micelles, by evaporation of the water from these effluents.
• concentrations of the various constituents of the composition according to the invention can be chosen to have a cloud point below the boiling point of TBP and its derivatives.
• the invention also provides an effective means of preparing a surface for radioactive decontamination.
• certain derivatives of TBP such as HDBP
• TBP irradiated nuclear fuel reprocessing installations
• certain derivatives of TBP form precipitates with most of the metallic radioactive cations present inside these installations.
• These precipitates are deposited on the surfaces of these installations in the form of colloids, and radioactive decontamination of these surfaces requires their erosion over a thickness of 2 to 10 ⁇ m. This erosion can only be effective after removal of the fatty solvents from these surfaces, in particular colloids, TBP and derivatives thereof, that is to say only after effective degreasing of these surfaces.
• the present invention also relates to a radiochemical decontamination process of a surface comprising in this order: degreasing of said surface by the process of the invention, and radioactive decontamination of the degreased surface.
• This radiochemical decontamination process makes it possible to treat surfaces contaminated by numerous radionuclides such as actinides and fission products.
• the surfaces, fatty substance (s), compositions, liquid, foam and gel may be those described above.
• the radioactive decontamination can be a decontamination by chemical erosion, for example a chemical erosion chosen from a cerium erosive treatment, an HF erosive treatment and a specific ruthenium treatment.
• Cerium erosive treatment consists in treating a surface by bringing this surface into contact with a treatment solution comprising a mixture of concentrated nitric acid and IV cerium, for a duration and at a temperature such that the erosion of this surface takes place over a thickness of 2 to 10 ⁇ m.
• concentration of nitric acid may for example be 2 mol.l -1 and that of cerium 0.05 mol.l -1 .
• the treatment can for example be carried out for a period of 2 hours, for example at 50 ° C., and can comprise agitation of the treatment solution. This treatment is intended to displace the fixed contamination in addition to the labile contamination linked to the solvent.
• HF erosive treatment consists in treating a surface by bringing this surface into contact with a treatment solution comprising a mixture of concentrated nitric acid and HF, for a duration and at a temperature such that the erosion of this surface occurs. made on a thickness of 2 to 10 ⁇ m.
• concentration of nitric acid may for example be 2 mol.l -1 and that of HF 0.1 mol.l -1 .
• the treatment can for example be carried out for a period of 5.5 hours, for example at 50 ° C., and can comprise agitation of the treatment solution.
• This treatment is intended to complex certain radionuclides such as Pu, Zr, U, Am and to displace the fixed contamination on the surface.
• the specific ruthenium treatment consists in treating a surface by bringing this surface into contact with a treatment solution comprising a mixture of KMn0 4 and sodium hydroxide.
• concentration of K n0 4 may for example be 0.05 mol.l -1 , and the sodium hydroxide concentration of 0.5 mol.l -1 .
• the treatment can for example be carried out for a period of 2 hours, for example at 50 ° C., and can comprise agitation of the treatment solution.
• This treatment is intended to eliminate contamination due to ruthenium 106 ( 106 Ru). It can be followed by soaking the surface in nitric acid.
• This radiochemical decontamination process is more effective than that of the prior art which included degreasing by the process of the prior art and an oxidation treatment which makes it possible to solubilize the ruthenium oxides.
• the process of the invention makes it possible to improve the radiochemical decontamination of a surface considerably, since measurements of residual radioactivity of the surfaces decontaminated by this process have shown a residual activity up to 20 times lower than that obtained. by the method of the prior art, and a measurement of the decontamination factor FD of these surfaces has shown a gain of the order of 10 compared to the prior art.
• a compatibility study of the composition according to the invention with the various treatments of degreasing effluents and possibly of decontamination of plant surfaces for reprocessing of irradiated fuels was carried out. This study has shown that a concentration by evaporation of the effluent, in a neutral or acidic medium, with a view to a reduction in volume of approximately 10 times, results in the obtaining of a biphasic concentrate which can be emulsified. by pumping for transfer to chemical treatment.
• Chemical precipitation in a non-concentrated effluent of various mineral absorbents of radioelements such as hydroxides, sulfates and insoluble ferrocyanides, and associated absorption of inactive tracers of Cs, Sr, Ce, Ru, on these compounds are not modified by the presence of a composition according to the invention.
• a comparison of decontamination factors in the absence or in the presence of a composition according to the invention shows that there is no change in the performance of a chemical insolubilization process due to this composition.
• the quantity of mud formed remains identical with or without composition according to the invention.
• Sedimentation of the suspensions, used as a means of solid / liquid separation in a second stage of chemical treatment of the effluents is little disturbed by the presence of surfactant compounds.
• a solid / liquid separation on a rotary filter with a diatom pre-layer, carried out under partial vacuum does not pose a problem with a composition according to the invention, for example when it has a concentration of approximately 1.38 g / 1 in aqueous solution: no foaming is observed and the presence of the composition according to the invention does not disturb the filtration.
• This example is a comparative example of the degreasing efficiency of a composition and of a process in accordance with the invention compared with solutions and a process of the prior art.
• the surface to be degreased is an austenitic steel blade covered with approximately 1 g / cm 2 one of the following mixtures A and B which represent the fatty substance to be dissolved.
• Mixture A 0.9% by weight of TBP + 0.1% by weight of a mixture comprising 60% HDBP and 40% H 2 MBP.
• the process of the prior art comprises the following sequences, in this order, and with stirring of the solutions used, by means of a magnetic bar, at 500 rpm:
• the method of the invention comprises soaking each blade in a composition according to the invention, without stirring, at a temperature of 20 ° C.
• two different compositions according to the invention are used. These two compositions each comprise 0.12% by weight of oleic alcohol ether and of polyoxyethylene glycol containing 20 units of ethylene oxide, from the trade name SIMULSOL 98 manufactured by the company SEPPIC (formula (I) above ) and 0.57% by weight of block copolymer containing 45 ethylene oxides and 9 propylene oxides from the trade name SYNTHIONIC P8020 manufactured by the company ITCO (formula (II) above).
• composition 1 A first of these two compositions, hereinafter called composition 1, comprises 0.5 mol.l -1 of NaOH, and the second of these compositions, hereinafter called composition 2, comprises 1 mol.l -1 of NaOH.
• the cloud point of these two compositions is 38 ° C.
• the degreasing efficiency of these two methods was compared by measuring the contact angle between an aqueous solution and each degreased metal strip, by the SCHULTZ method, and by measuring the minimum contact time for total degreasing of these strips.
• a wetting angle equal to 0 indicates total degreasing of the surface, that is to say a recovery of the grease from the metal surface.
• the aqueous solution must allow its micellization.
• Table 1 comparative example of degreasing a metal blade
• Example 2 Degreasing kinetics of a surface with a composition according to the invention
• a metal blade covered with 0.75 g / cm 2 of a mixture C of TPH solvent + TBP + HDBP + H 2 MBP comprising 70 respectively; 27; 1.8 and 1.2% by weight of these solvents and a metal strip covered with 1.2 mg / cm 2 of a mixture D of solvent TBP + HDBP + H 2 MBP comprising 90 respectively; 6 and 4% by weight of these solvents are degreased by soaking without stirring in an aqueous solution of the composition according to the invention comprising 0.5 mol.l -1 of sodium hydroxide, 0.12% by weight of SIMULSOL 98 (brand and 0.57% by weight of SYNTHIONIC P8020 (trademark). Degreasing is carried out at room temperature.
• the degreasing kinetics is followed by measuring over time, and at regular intervals, the surface tension ⁇ cos ⁇ of each blade by the submerged blade method of WILHELMY and by determining the corresponding cos ⁇ .
• Table 2 below collates the results of this example.
• Table 2 Degreasing kinetics of a surface with a composition in accordance with the invention
• Example 3 degreasing efficiency of a surface with a weak foaming composition according to the invention
• This example illustrates the effectiveness of degreasing a surface with solutions of weakly foaming compositions according to the invention.
• compositions used comprise a constant concentration of sodium hydroxide equal to 0.5 mol.l -1 , and a constant concentration of ether oleic alcohol and polyoxyethylene glycol equal to 0.2% by weight.
• the fatty alcohol used is SIMULSOL 98 (trademark). manufactured by the company SEPPIC.
• These compositions comprise a variable concentration of block copolymer of the trademark SYNTHIONIC P8020 manufactured by the company WITCO, and also comprise a foam-inhibiting agent in an equally variable concentration.
• This foam-inhibiting agent is an alkyl phosphate of the trademark MONTALINE ANP manufactured by the company SEPPIC.
• the surface to be degreased is a steel blade coated with 1 mg / cm 2 of TBP.
• Degreasing is carried out at room temperature and without stirring the degreasing solutions.
• the degreasing efficiency of these solutions is evaluated by measuring the cloud point (in ° C) of each of these solutions, by measuring the time, in minutes, necessary for each of these solutions to completely degrease the metal blade of so as to obtain a surface tension such as cos ⁇ l, and by a measurement of the quantity (in g / 1) of TBP that each solution can dissolve.
• Table 3 below collates the results of this example.
• Example Example of a foam comprising the composition according to the invention
• the solutions used to form the foam of this example comprise a concentration of SIMULSOL 98 (trademark) greater than or equal to 0.4% by weight, a concentration of SYNTHIONIC (trademark) greater than 0.26% by weight, and further include a foam destabilizing agent.
• This destabilizing agent is MONTALINE ANP (brand of previously described as a foam inhibitor.
• all the compositions comprise a constant sodium hydroxide concentration equal to 0.75 mol.l -1 .
• Foams were made from these compositions from a static generator composed of a cylinder 120 mm long and 8 mm in diameter filled with 3.24 g of a porous packing of FORAFLON type (trade mark ).
• the generator was supplied with each foaming solution using a gear pump with a flow rate of liquid from 23 to 28 l / h and air at 88 1 / h under normal conditions of temperature and pressure.
• the foams are obtained at a rate of 120 to 130 l / h, with an expansion ranging from 6 to 7 and a shelf life of 15 + 2 minutes.
• TBP and its HDBP and H 2 MBP derivatives was measured (in g / kg) which can be dissolved in different compositions according to the invention.
• the tests were carried out at room temperature.
• composition comprising 0.75 mol.l "1 NaOH, 0.8% by weight of SIMULSOL 98 (trademark), 0.6% by weight of SYNTHIONIC P8020 (trademark) and 0.4 % of MONTALINE ANP
• Example 4 Example of a gel comprising the composition according to the invention
• the gel produced in this example comprises 1 mol.l "1
• This viscosifier is xanthan gum from trademark KELZAN 140X and it is added to the composition according to the invention in an amount of 1.2% by weight.
• the gel obtained has a viscosity of 0.8 Pa.s (800 cps) which varies little with temperature. This gel makes it possible to degrease a metal blade covered with TBP and its derivatives with the same efficiency as the compositions of Examples 1 to 3 above.
• Example 5 Comparative Example of Radiochemical Decontamination of a Surface Between a Process According to the Invention and a Process of the Prior Art
• This example is a comparative example of the effectiveness of radiochemical decontamination of a surface by a method of the present invention compared to radiochemical decontamination according to the prior art.
• the surfaces to be degreased and radioactively decontaminated are substantially cylindrical sections of stainless steel coming from organic phase probes from a nuclear fuel extraction plant. They were numbered from 1 to 9. These surfaces were in contact with TBP, TPH, HDBP and H 2 DBP, and their radioactivity is due to more than 98% to ruthenium 106 ( 106 Ru). Before sampling, they were rinsed with concentrated nitric acid and then a measurement of their radioactivity at 106 Ru. This activity will be called A 0 below and corresponds to the activity of each surface before radiochemical decontamination.
• the radiochemical decontamination processes in this example include degreasing of each surface, either according to a process of the prior art described in Example 1, either according to the method of the invention, and radioactive decontamination by an erosive treatment.
• the method of the invention used in this example comprises the following three steps, in this order:
• SIMULSOL 98 (trade mark) and 0.57% by weight of SYNTHIONIC P8020 (trade mark) at 21 ° C without stirring, and - soaking in a 0.5 mol solution 1-1 for one hour at 50 ° C with stirring.
• radioactive decontamination FD1 —— is calculated for
• AR1 each degreased surface.
• Table 5 below groups together the results of these measurements and calculations and makes it possible to compare the effect of degreasing according to the invention on the radioactive decontamination of a surface, compared with the prior art.
• AR1 residual activity 106 Ru of the surface after degreasing
• Erosive is either a cerium IV erosive treatment (TE Ce IV) for 2.5 hours, or an HF erosive treatment (TE HF) for .5.5 hours, or a ruthenium erosive treatment (TE Ru) for 2 hours, the latter treatment being followed by soaking in HN0 3 for 1 hour.
• TE Ce IV cerium IV erosive treatment
• TE HF HF erosive treatment
• TE Ru ruthenium erosive treatment
• the FDT decontamination factor is that obtained for the degreasing and decontamination of each surface.
• Example 6 Decontamination of an active cell with a gel according to the invention
• the decontaminated cell had for function the U / Pu partition (2nd extraction cycle).
• the contamination of the floor of this cell was caused by leaks of solvent loaded with U and Pu which were more or less spread by the workers. Part of this solvent was more or less radiolysed, which produced tarry black deposits.
• the average level of alpha surface contamination has been estimated at a little less than 2 Mbq / cm 2 , ie, taking into account a floor area of approximately 30 m 2 , a total activity in alpha emitters of 0.57 Tbq.
• the average isotopic composition (% by mass) determined on the recovered waste is as follows:
• the dose rates measured in the cell fluctuated before any decontamination operation, between 0.3 and 10 mGy / h depending on the zone.
• the gel was applied to the floor (30 m 2 ) using a roller per 5 to 6 m 2 portion, with particular emphasis on the areas identified as being the most irradiating.
• the contaminated gel was collected using a squeegee and then subjected to natural drying in its original pot.
• the most contaminated part of the cell (process side) was sanitized in 4 sequences with approximately 2 kg of gel / m 2 .
• the cell floor is perfectly wettable by nitric acid after degreasing.
• the nitric acid used was recovered using polypropylene wipes.
• the relative error of this type of measurement determined following a test campaign involving more than a hundred different measurements is 25%.

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