EP0126060B1 - Transformation into storable form of ion-exchange resins, in particular those containing noxious substances - Google Patents

Description

The invention relates to a process for converting anion-containing resins containing, in particular, pollutants, preferably containing and / or releasing free reactive amines, and / or mixtures containing these anion-exchange resins under heat treatment in a state suitable for intermediate or final storage.

A large part of all radioactive and / or toxic waste in nuclear power plants, nuclear fuel processing plants, chemical-technical companies, etc. is generated in the form of aqueous solutions. There is therefore always the need to separate the relatively small amounts of pollutants from the large proportions of water so that it can be safely returned to the ecological cycle. The ion exchange process lends itself very well to this. The dissolved pollutants can be largely removed from large volumes of diluted solutions in a simple working step and concentrated in order of magnitude in ion exchange resin. For repeated use of an ion exchange resin, it has to be regenerated after each loading, the bound ions being dissolved again and thus being diluted again. Especially when binding pollutants, multiple use of the ion exchange resin, which counteracts the principle of concentration and thus uneconomically increases the workload, is mostly avoided. So-called single-use ion exchange resins are primarily used here, ie ground ion exchange resins with a grain size of approx. 4 µm. They are washed up in thin layers - a few millimeters to a few centimeters - on suitable filter elements Relatively high flow velocities and removed before del breakthrough of the pollutants through the layers by rewinding from the precoat filter.

The powder resins which are loaded in this way and accumulate in considerable quantities, or else the exhausted spherical resins which are loaded in columns, are usually centrifuged off from the adhering water and transferred in loose containers to storage containers and stored temporarily. Since storage in bulk can cause environmental pollution, e.g. by knocking out the containers and / or leaching the ion exchanger in the event of water ingress in the event of a catastrophe, efforts are being made to convert the ion-exchange resins loaded with pollutants, in particular the anion-exchange resins, into a stable, final storage form.

The various methods that have been proposed in this context always have considerable disadvantages:

Direct combustion of ion exchange resins places a heavy load on the incineration plant and contradicts the principle of concentration of pollutants because considerable amounts of the pollutants are released in the form of fly ash and dust. The service life of the large-volume filters required for the operation of such incinerators is shortened considerably. The used filters must also be disposed of, so that in the end only an insignificant reduction in volume is achieved.

Wet combustion, for example according to GB-A 1 418 330, with liquid oxidizing agents, such as mixtures of Concentrated sulfuric acid with strong oxidizing agents, such as nitric acid or nitrogen dioxide etc., also supplies large quantities of pollutant-containing solutions with a high acid or salt content. The necessary further processing of such solutions is complex.

Directly embedding ion exchange resin, which is still moist after centrifuging, in matrix materials such as cement, bitumen or synthetic resin, as is currently practiced at present, is problematic for several reasons. First because of the swelling pressure on the matrix caused by the exchange resin when the solidified material enters the water, which can lead to the destruction of each matrix and because of the following individually different problems with the stated hardening agents:

Poor incorporation of ion exchange resins in the cemented product leads to loosening of the matrix when the resin dries out and to the release of low molecular weight amines into the atmosphere.
The release of gaseous compounds from the resin structure of the anion exchanger when introduced into a heated bitumen melt leads to inhomogeneous products due to foam formation and to an increased workload and storage space load due to the toxicity of individual gases, eg the amines.
The embedding of large amounts of moist exchange resins in a synthetic resin matrix leads in particular to the release of water vapor by the heat of reaction, with radioactive materials additionally causing an increased radiolytic attack on the residual water, the resin structure of the ion exchanger and the matrix material, and problems of homogeneity. Any particular disadvantage must be the significantly higher proportion of material costs compared to consolidation with cement or bitumen will be charged.

From FR-A 2 361 724 it is known to embed cation exchange resins in a basic environment in a thermosetting resin. However, cation exchange resins do not contain amines, which are difficult to dispose of. Furthermore, the cation exchange resins are not processed to a dry mass, so that the difficulties encountered when embedding moist masses have to be overcome.

Furthermore, e.g. known from DE-A 2 851 231 thin film dryer for the treatment of waste.

The method according to AT-A 338 388 represents a further development compared to the methods mentioned so far, in which ion exchange resins are thermally decomposed in a medium that does not maintain combustion. The thermal decomposition of anion exchange resins begins at a temperature above 280 ° C. Accordingly, according to this AT-A, temperatures of less than 500 ° C., preferably between 280 and 500 ° C., are selected for the decomposition. The resins are thus converted into a form which is sufficiently stable and storable even against radiolytic decomposition. This product can be stored in the received form, or additionally embedded in concrete or bitumen and protected against possible leaching, in appropriate landfills, since the resins have been heated above their decomposition temperature.

Considerations as to how the energy-intensive decomposition temperatures of 280 to 500 ° C and the batch processing of the material used, the pollution of the workplace with toxic exhaust gases, in particular with the amines released during the decomposition of the anion exchange resins, can be avoided led to the development of the process of the invention The type mentioned at the outset, which is characterized in that the anion exchange resins or the mixtures containing them are heated in the presence of or in contact with water and an alkaline substance at least until the anion exchange resins begin to decompose and the amines are released and the amines formed, essentially dry mass is filled into a container intended for intermediate or final storage.

It is particularly preferred if the milieu in which the Anion exchange resins or mixtures containing them are adjusted to a pH of at least 9 or when the anion exchange resins or mixtures containing them are heated in thin layers.

The process is particularly advantageous if the temperature is raised to a temperature of up to 280 ° C., preferably between 110 and 270 ° C., preferably between 140 and 250 ° C., particularly advantageously to approximately 210 ° C., which can advantageously contribute to effectiveness if the mixtures are heated to these temperatures rapidly, preferably in less than 5 min, preferably in less than 2 min, in particular in less than 40 s. With regard to the pollutants, it is advantageous if the heating of the resins or mixtures and, if appropriate, also the subsequent filling and embedding at pressure below the ambient gas pressure, preferably at 50-300 mb, in particular at 120-180 mb, is absolute is made.

Surprisingly, it has been found that when the resins mentioned or mixtures containing them, e.g. at pressures of 50 - 300 mb absolute and temperatures below 280 ° C, e.g. in thin-film dryers, the resins are degraded to such an extent that they largely lose their swellability and the associated disadvantages for safe storage, loose or embedded in a matrix. With the reduction in swelling capacity, the exchangeability of the bound ions, mostly of pollutants, is also minimized.

The process according to the invention thus provides a rapid, energy-efficient disposal or final storage form of anion-exchange resins containing free reactive amines or of those containing them Anion exchange resins or mixtures containing them possible. Mixtures are understood to mean all types of materials, for example sludges, suspensions, etc., which contain such anion exchange resins, which in turn can be loaded with any substances, in particular pollutants, for example toxic and / or radioactive substances and the like.

It is preferred if the mass obtained after heating under alkaline conditions is converted into a liquefied, high molecular weight organic embedding mass with bitumen and / or tall oil pitch and / or paraffins and / or essentially containing at least one amine-curing polymer and / or other amine-binding organic compound introduced non-amine-curing polymer, preferably sunk sedimentatively under the effect of its own weight. Some or all of the bitumen can be substituted by montan wax, earth pitch, ozokerite or the like. In the following, only the expression bitumen is used for this. This creates a solid and dense matrix for the embedded resin degradation products.

It can e.g. To prevent further amine release, it may be advantageous if the mass obtained is introduced into a liquefied embedding compound, preferably a bitumen melt, the temperature of which is lower than that when the anion exchangers or mixtures containing them are heated, in particular to 120 to 210 ° C., preferably to 160 is kept up to 190 ° C.

In order to ensure further residual amine binding, one can proceed in such a way that after the embedding has taken place, the embedding compound is brought to a temperature which is higher than the embedding temperature.

According to a further particularly preferred process variant, it is provided that the amines or the vapors released when the anion exchange resins or the mixtures containing them are heated, preferably at a pressure below the ambient gas pressure, with a, preferably a pH of at most 4, comprising, aqueous solution of at least one acid, which is optionally at least partially an acid, the amine salts of which are biodegradable, preferably brought into contact with, preferably passed through, citric acid and / or tartaric acid and / or acetic acid, as a result of which hazard and environmental pollution are caused the vapors of the heating process can be avoided.

Likewise, in particular in order to reduce the environmental impact, it is advantageous if the gases and / or vapors obtained after contacting the amines or the vapors containing them are subsequently brought into contact with an alkaline solution.

A particularly preferred device for carrying out the method according to the invention has a heating and drying device and a device for the extraction of gases and / or vapors from the heating and drying device when the pressure is below the ambient gas pressure, the heating and drying device having at least one Device for the separation of gases and / or vapors formed there is connected, and is characterized in that between the heating and drying device for the alkaline anion exchange resins and the suction device contains a gas or amines released from the heating of anion exchange resins or mixtures containing them Steam-flowable reactor, with a, preferably aqueous, solution of a, preferably biodegradable, acid, and that the heating and drying device has an outlet lock leading to a container e has.

The reactor can e.g. an absorption vessel, vapor washer, mixing reactor or the like. which contains the solution of the acid into which the amines or vapors are sucked off with the evacuation device, e.g. a suction jet pump. Thin-film dryers have proven to be particularly suitable as heating devices, and are described, like the evacuation devices, for example in AT-PS 336.739 and 336.146.

In the device described, any leakage of toxic substances released from the exchange resins, in particular amines, into the surrounding atmosphere is completely avoided, since they are bound by the acid in the reactor integrated in the system.

It may also be advantageous for environmental reasons if the reactor mentioned is followed by a further reactor which contains an alkaline medium for binding the acid gases and / or vapors coming from the acid reactor, it advantageously being provided that the suction device preferably has one with a Jet ejector is fed from the medium taken from the second reactor. To monitor the process, control and control devices for the pH values in the reactors are advantageously provided, as are the entry device for the anion exchange resins and the heating device.

The exchangers thermally degraded according to the invention in an alkaline medium can, for example continuously, be discharged through a vertical thin-film dryer as a heating device via a lock system under negative pressure into the storage container used in a recipient will. The dried substances accumulated during the change of the filling container are collected in the lock and then discharged into the container adapted to the operating conditions. The storage container advantageously contains a matrix material, in particular for final storage.

The finished liquefied embedding compound with the amine-binding additives can be supplied to the storage container via a supply line. A feed device for the additives opening into the feed line to the storage container or into an embedding material storage container is advantageously provided. The substances embedded in this way no longer release gases, are therefore homogeneously distributed in the matrix without gas bubbles and foam formation and are particularly suitable for safe storage against leaching. The additions, in particular bitumen-soluble epoxy compounds and / or acid anhydrides and / or phenolic resins to the embedding melt, bring about significant consolidation, especially in the case of bitumens, after the amines have been incorporated into the synthetic resins. The penetration and softening point of the solidified matrix are significantly shifted to higher values, which also significantly improves the thermal load capacity of the final mass. As such, it is possible to store the materials temporarily after leaving the heating device. Such intermediate products can, if necessary, be embedded in the matrix material at a later time under conditions as described above, advantageously after reheating.

The embedding compound for the essentially dry compound contains at least 0.5% by weight, preferably at least 2% by weight, reactive amine-binding additives in the basic compound of the embedding compound in the bitumen and / or paraffin and / or tall oil pitch, preferably bitumen , preferably epoxy compounds, in particular glycides and / or epoxy resins, and / or, preferably organic, acid anhydrides, in particular dodecenylsuccinic anhydride, and / or reactive phenolic resins, preferably in solution. The embedding compound therefore contains, in the organic matrix, preferably soluble, reactive compounds which can react with the free amines or amine groups to form stable compounds. As has been found, this composition is also very suitable for anion exchange resins which have not been pretreated thermally or are only dried, or mixtures containing them. In this case, although compounds with smaller molecules are formed and the amount of reactive compounds to be used is greater, the products obtained are more stable than those which are embedded in a matrix without reactive additives.

Mixtures containing anion exchange resins are e.g. Anion-cation exchange resin mixture, sludges containing anion exchange resins, mixtures of anion exchange resins with pollutants and the like. to understand, in particular anion exchange resins present in aqueous, alkaline suspension or mixtures containing them.

If bitumen is chosen as the base material for the embedding material, there is the advantage that the products obtained remain plastic and cracks which heal under mechanical stress heal on their own.

Other advantages of such embedding compounds are high resistance to radiolytic decomposition, the water-repellent properties and high resistance to aging and thermal decomposition. In contrast, only ion exchange resins embedded in synthetic resin have only higher mechanical strength. Petroleum bitumens are particularly suitable as the base material, but also natural bitumens, such as natural asphalt, montan waxes, earth pitch, ozokerite and / or the like. The selection of the proportions of the individual substances contained in the base material also depends, inter alia, on the degree of thermal pretreatment of the anion exchange resins.

It is advantageous if anion exchange resins are used after a pretreatment carried out at a higher temperature than is used for the introduction into the bitumen melt in order to avoid foaming or outgassing of the melt. Analogously should. the amine-reactive compounds are selected so that a reaction takes place to the required extent at the selected temperatures. The addition of bitumen-soluble epoxy compounds and / or acid anhydrides and / or reactive phenolic resins as an amine-binding substance to bitumen has the effect that the embedding compound is significantly solidified after incorporation of the amine into the respective synthetic resin structure. The penetration and softening point of the matrix are shifted to significantly higher values, which significantly improves the thermal load-bearing capacity of the solidified product.

The structure of the matrix can be further strengthened by adding fibrous aggregates. Mineral fibers, such as, for example, asbestos, rock wool, or glass fibers, or organic fibers, such as, for example, fibers with cellulose and their derivatives, or plastic fibers, such as, for example, with polyester, polyamides or Like. Or carbon fibers used. In particular, waste fibers or waste from fiber production can also be used for this purpose.

The amine-reactive additives are advantageously added to the base composition in such amounts that their negative properties, if any, do not impair the properties of the base composition. Their amount is also advantageously chosen to be somewhat larger than is necessary for amine binding.

With regard to their properties for underground storage, embedding compounds are particularly preferred in which the reactive amine-binding additives are present in total amounts of at most 50% by weight, preferably at most 30% by weight, based in each case on the base material.

High strength of the compositions can be achieved particularly favorably if, based in each case on the base composition, 2 to 30% by weight, preferably 5 to 20% by weight of epoxy resins or 0.5 to 30% by weight, preferably 1 to 20 wt .-%, low molecular weight epoxy compounds, preferably glycides, preferably butylene glycol diglycidyl ether, are contained.

Furthermore, it has proven to be economically advantageous if, based in each case on the basic composition, 0.5 to 20% by weight, preferably 1 to 15% by weight, acid anhydride, preferably dodecenylsuccinic acid hydride, or 2 to 50% by weight , preferably 5 to 30 wt .-%, phenolic resin are included.

The base composition particularly preferably contains at least 50% by weight, in particular 75% by weight, of bitumen. Also bitumen base compositions with up to 30% by weight, in particular up to 10% by weight Tall oil pitch, based on bitumen, has proven itself.

It can be advantageous if at least one amine-reactive additive is only formed from the added starting materials in the molten matrix, which may have already been mixed with other reactive additives.

When embedding itself, the preferred procedure is to prior to and / or during and / or in the basic mass formed with higher molecular weight substances or their mixtures, in particular bitumen and / or montan wax and / or ozokerite and / or paraffin and / or tall oil pitch after the addition of the material to be embedded, if appropriate those which have been thermally pretreated in alkaline form and which are reactive, in particular the previously described amine-binding additives and, if appropriate, the additives which reinforce the mechanical structure of the matrix, are added. Advantageous embedding temperatures are below 280 ° C, in particular 120 to 220 ° C, preferably 160 to 220 ° C.

For sedimentation, it is advantageous if the admixture of the additives and / or the introduction of the anion exchange resins or their breakdown products or the breakdown products of the mixtures containing them, which are in solid form, under reduced pressure, preferably at 50-300 mb, in particular 120 - 180 mb, absolute.

A further advantageous embodiment of the method consists in the optionally thermally degraded ion exchange resins or the mixtures containing them the base material and the reactive additives, optionally with the addition of the additives, preferably by means of a screw extruder.

The invention is described below by way of example with reference to the drawing. The system shown there is based on a known system as used for vacuum sedimentation for embedding dried, bio-harmful waste products according to AT-PS 336.739 and 336.146.

A vertical thin-film dryer 2 is fed from a container 1, optionally ground, anion exchange resins or mixtures containing them in basic, aqueous form, for example as a suspension. The exchangers or mixtures are preferably mixed with NaOH, the pH being regulated to 9-11 by means of a monitoring device 12. Furthermore, a feed device 13 for alkaline medium, for example NaOH, opens into the container 1. The exchangers or mixtures are fed to the container 1 by means of a pump 14 or the like. The suspension is introduced into the dryer 2, preferably continuously, via a pump 15. The substances entered form a thin film on the inner wall of the thin-layer dryer 2, which is dried very quickly. Blades 16 driven by a motor 18 via a shaft 17 scrape the dried mass, which contains the solid breakdown products of the exchange resins or the mixtures used, and these fall into a lock 3 with a locking mechanism 19. When the lock 3 is opened, the dried mass enters one Container 6, which is arranged in a recipient 5, so that container 6 is also under the action of a suction device 11 and good sedimentation of the dry matter in the container 6 located melt of the investment material is achieved. It is also possible to stir in the dried substances. The liquefied embedding compound is fed to the container 6 from a storage container 4 via a pump 20 and a quantity measuring device. Furthermore, a container 22 is provided, from which amine-binding additives can be supplied to the base material via a pump or metering device 23.

In the container, the dried and degraded exchanger residue together with the pollutants it contains can also be collected loosely or introduced into a matrix provided according to the invention, in particular based on bitumen with the additives. The thermal degradation or the thermal degradation with subsequent embedding in a corresponding matrix, advantageously a bitumen matrix, can thus be carried out. The amines released from the resins during heating in the dryer 2 are sucked out of them by means of a suction device 11. In the suction path there is a dust separator 7, from which the return of separated dust into the container 1 via a lock 21 is possible. After the dust separator 7, the gases and / or vapors containing the amines enter a reactor 8 which contains an aqueous acid solution for binding the amines, the pH value of which is monitored by monitoring device 28. Reactor 8 is advantageously cooled. The reaction products formed can be discharged via a line 24. The acid medium in the reactor 8 can be kept at a constant level, for example by means of a controlled metering pump. The solution can be charged with mineral acids, for example sulfuric acid, nitric acid, phosphoric acid, etc. and / or biodegradable organic acids, for example acetic acid, citric acid and / or tartaric acid can be adjusted to pH values between 0 and 4 by means of pH meter 28 and metering device 29. A metering device 35, which is controlled by a pH meter 30, is provided in an analogous manner for the reactor 9. Acid vapors and / or gases drawn off from reactor 8 with pump 11 are passed into further reactor 9, which is preferably cooled and contains alkaline medium. The reaction products are discharged from the reactor 9 via a line 25. A branch of a circulation line 33 leading to the pump 11 also emanates from the reactor 9 and is used to convey medium from the reactor 9 as a blasting medium into the pump 11, which works on the ejectro principle. On the output side of pump 11, the reactor medium is intimately mixed with the gases in the second branch of line 33. As in reactor 8, the pH of the medium of reactor 9 is monitored by a control device 30 and subsequently supplied with an alkaline medium. Finally, the cleaned gases can pass from the reactor 9 into the atmosphere via a filter 10. In this way, the amines formed during the heating and sucked off by the suction device 11 formed by the suction jet pump are rendered harmless in gases and / or vapors.

The system shown is essentially a closed system, which is under rough vacuum during operation. Thin-layer dryer 2, lock 3, storage container 4, storage container 6 or recipient 5 and the associated lines 31 for embedding compound and, if appropriate, for the additives can be heated by means of heater 32. The energy can be supplied electrically by superheated steam or a heat transfer medium, which is brought to the required temperature by means of a heater and pumped in the circuit. The other parts of the plant are preferably unheated and thus allow the complete condensation of aqueous components and binding of amine pollutants from the vapors and / or gases. Reactor 8 and / or reactor 9 can be cooled by means of cooling devices 34. The reactors 8 and / or 9 can also be designed in two stages and each have an upstream condenser from which the condensate can be fed into the respective reactor vessel with acid or alkali.

The invention is explained in more detail below with the aid of exemplary embodiments; the% by weight data relating to embedding compound without additives, such as fibers or the like. In the following, “mixture” is also understood to mean anion-cation resin mixtures with or without pollutant loading with adhering sludges etc.

Example 1:

300 kg loaded spherical single-use ion exchange resin with approximately equal proportions, cation exchanger, Lewatit SP 120, and anion exchanger, Lewatit MP 500, are ground in a continuous mill for wet grinding after suspension in 1000 l of water, a suspension with particles of approximately 50 μm being formed will. This suspension is concentrated with 20 - 50 kg. Sodium hydroxide solution added and the strongly alkaline suspension is conveyed from a collection container into a thin-film vertical dryer at a flow rate of 60 l / h.

The dryer heating zone is heated to 210 - 220 ° C, the system vacuum set to 130 - 150 mb. Before the thermal degradation process begins, a 200 l steel sheet drum is placed in the waste container recipient, in which around 100 l of liquefied embedding material are submitted according to the invention at 170 ° C. The melt contains 85 kg of standard bitumen B15, 10 kg of tall oil pitch and 5 kg of epoxy resin with an epoxy equivalent weight of 190 (eg Epotuf 37 - 140 from Reichold Chemie AG).

The thermally degraded exchange resin or mixture heated in the dryer gets into the melt of the embedding compound and sediments under the effect of gravity, the reduced pressure and the surface forces into the melt, which is kept at 170 ° C for 0.5 h to react, whereby every single grain is covered with a thick covering of matrix material. With this embedding, all reactive residual amines are chemically bound by the epoxy resin of the embedding compound and the resulting molecular complexes contribute to the additional solidification of the bitumen matrix.

Depending on the loading of the resin mixture, around 100 kg of degraded resin are obtained under the specified working conditions, which are present in 100 kg of investment material. With the lock on the dryer, a continuous process of the entire process is guaranteed even when changing containers. After the loaded mass has cooled, it can, as it is optimally leach-proof, be sent to long-term storage in a landfill, with neither fear of destruction of the matrix by swelling in the event of water ingress nor impairment of the landfill circulating air by toxic and explosive amine vapors, even during long-term storage.

Example 2:

An aqueous suspension with 20 - 30 wt .-% mixed, used ion exchange resins in powder form, for example: Powdex resin from equal parts of cation exchange resin PCH and anion exchange resin PAO, according to Example 1, is adjusted to a pH value of 9-11 with concentrated sodium or potassium hydroxide solution. The prepared suspension is then fed with the metering pump into a thin-layer rotary evaporator, as already described in Example 1, according to the performance of the evaporator, for example in amounts of 55-60 l / h. The suspension placed in the evaporator is absolutely dried at 190 ° C and 100 mb and the exchangers are thermally degraded. The volatile degradation products are bound by means of gas scrubbing according to Example 1, vapors are condensed in a separate condenser if necessary. The dried, heated resin degradation products together with other solid substances are collected in containers and, if appropriate after interim storage, embedded in an embedding melt with 92% by weight of standard bitumen B40 and 8% by weight of dodecenylsuccinic anhydride at 170 ° C. The reactive residual amines contained in the resin degradation product are bound by the acid anhydride in the matrix.

The reactive additive, in this case dodecenylsuccinic anhydride, can also be formed directly in the bedding from these added starting materials. For example, a corresponding amount of dodecenylsuccinic acid can be added to the base material or also an embedding material and dodecenylsuccinic anhydride can be formed by heating and optionally applying negative pressure by removing water from the melt.

Example 3:

• a) Das abgebaute Ionenaustauscherharz samt weiteren Reaktionsprodukten wird in ein vorgelegtes, aufgeschmolzenes Gemisch mit 91,5 Gew.-% Normbitumen B40, 8 Gew.-% Epoxidharz (Epoxid-Äquivalentgewicht ca. 350, z.B. Shell Epon 864) und 0,5 Gew.-% Dodecenylbernsteinsäureanhydrid bei 190°C und 180 mb absolut einsedimentiert; reaktive Restamine werden von den Zusätzen gebunden.
• b) Wenn keine nennenswerten Anteile Kondensat bei Erhitzung mehr anfallen, läßt man bis unterhalb 190°C abkühlen und überführt anschließend die thermisch abgebaute Masse der Harze, in eine Bitumenschmelze mit 96 Gew.-% Normbitumen B15 und 4 Gew.-% Dodecenylbernsteinsäureanhydrid. Die Einbringung kann mittels langsam laufendem Rührwerk erfolgen. Nach erfolgter Einbringung läßt man bei etwa 190°C das Gemisch bei 180 mb absolut etwa eine Stunde reagieren, wobei die Restamine gebunden werden. Fasern können dem Austauscherharz vor dessen Einsatz in den Drehtrockner und/oder nach dessen Abbau im Trockner und/oder der Bitumengrundmasse und/oder der Einbettmasse vor oder nach der Einbringung der Ionenaustauscherharze zugesetzt werden. Die Menge der zugesetzten Fasern beträgt bis zu etwa 15 Gew.-%.

Used ion exchange resin is backwashed with water from a commercial filter system and transferred together with the backwashing solution with lye into a strongly alkaline mixture. After the majority of the water has been separated off, for example by centrifugation, the wet ion exchange resin with the adhering hydroxide sludge is metered into a rotary kiln, for example with a vacuum conveyor, and is broken down absolutely in accordance with Example 1 at 260 ° C. and 150 mb. The volatile degradation products, especially the amines, are held in acid and alkaline-loaded washing devices.

• a) The degraded ion exchange resin together with other reaction products is placed in a melted mixture with 91.5% by weight of standard bitumen B40, 8% by weight of epoxy resin (epoxy equivalent weight approx. 350, eg Shell Epon 864) and 0.5% by weight .-% dodecenylsuccinic anhydride sedimented at 190 ° C and 180 mb absolutely; reactive residual amines are bound by the additives.
• b) If there are no significant amounts of condensate when heated, the mixture is allowed to cool to below 190 ° C. and then the thermally degraded mass of the resins is transferred to a bitumen melt with 96% by weight of standard bitumen B15 and 4% by weight of dodecenylsuccinic anhydride. It can be introduced using a slow-moving agitator. After the introduction, the mixture is allowed to react at about 190 ° C. at 180 mb absolutely for about an hour, the residual amines being bound. Fibers can the exchange resin before its use in the rotary dryer and / or after its degradation in the dryer and / or the bitumen matrix and / or be added to the investment material before or after the introduction of the ion exchange resins. The amount of fibers added is up to about 15% by weight.

Example 4:

420 l of an evaporator concentrate, similar to that obtained after wastewater distillation in pressurized water nuclear power plants, with 40 kg sodium borate, 6 kg trisodium phosphate, 19 kg sodium sulfate, 3 kg iron III hydroxide, 6 kg diatomaceous earth and 52 kg used ion exchange mixture in a ball - and powder form are adjusted to a basicity of approx. pH = 10 with building material lime. The mixture is then treated in a continuous mill in such a way that, in particular, the ion exchanger particles are comminuted to particle sizes of less than 50 μm. The viscous suspension is metered in with a metering pump according to the evaporating capacity at 60 l / h and a thin-film dryer at 210 ° C at 160 mb absolute. The solids are dried, the ion exchange resin is degraded and the volatile degradation products are retained in the system in accordance with Example 1. The dried product, mixed with the degraded ion exchange resin, is passed directly into a potting melt with 89% by weight of standard bitumen B80, 9% bitumen-soluble epoxy resin (epoxy equivalent weight of about 190, Epon 828, Shell AG) and 2% by weight of butylene glycol diglycidyl ether 120 ° C introduced, while remaining reactive amines are fixed.

Example 5:

According to Examples 1 and 2, a powder resin mixture with cation and anion exchange resin (Powdex PCH and Powdex PAO) is thermally broken down and stored temporarily. 45 kg of this mined resin mixture are continuously fed into one in a metering device 100 l steel barrel of embedding compound with phenolic resin (Viaphen PA 101, Vianova) melted from 45 kg at 70 - 80 ° C and 10 kg of epoxy resin (Epotuf 37 - 140), after which the mass was heated to about 100 for reaction - 110 ° C for 1 h. The reactive residual amines of the exchange resin are fixed in the matrix, which after cooling and curing is extremely dimensionally stable, thermally resilient and leach-resistant.

Example 6:

A mixture of spent spherical ion exchange resins (Lewatit SP 120, Lewatit MP 500), which was broken down in accordance with Example 1 and then stored in accordance with Example 2, is embedded in a bitumen synthetic resin matrix as follows:

50 kg of B 200 standard bitumen (softening point: approx. 40 ° C) are heated to 80 ° C in a 200 l steel drum. 50 kg of bitumen-soluble phenolic resin (Viaphen PA 101, Vianova) are introduced into the melt in portions and melted or dissolved. 78 kg of the thermally degraded ion exchange resin mixture are intimately mixed with 10 kg of epoxy powder (Araldit AT 1, Ciba / Geigy). The mixture is metered into the bitumen-phenolic resin melt with stirring, which is heated at 110 ° C. for 2 hours and thereby reacts, residual reactive amines of the exchange resin being bound by the epoxy resin in the matrix.

After cooling, the product has properties similar to those obtained in Example 5; the resistance to breakage is increased due to the increased toughness of the matrix.

Example 7:

200 kg of consumed ion exchange resin in powder form (Powdex PCH and Powdex PAO) are thermally broken down in accordance with Example 1 or 2 and, without removing the breakdown product from the plant, it becomes absolute at 170-180 ° with a prevailing plant pressure of approximately 160 mb C embedded in a matrix melt placed in a 200 l container with sedimentation, the reactive amines being bound. The matrix melt contains a mixture with 60 kg raw montan wax and 60 kg paraffin (solidification point 54 - 56 ° C), to which 10 kg dodecenylsuccinic anhydride are admixed as an amine-binding substance. After the introduced 70 kg of degradation products have been sedimented in the storage container, the container with the embedding product is removed from the system after flooding the recipient to normal pressure. After solidification, the mass is also homogeneous, leach-resistant and dimensionally stable.

Example 8:

A powder resin mixture of cation exchange resin and anion exchange resin (Powdex PCH and Powdex PAO) is dried in a drying chamber at 120 ° C and stored temporarily. 90 kg of this degraded resin mixture are continuously metered into an embedding compound placed in a 200 l metal drum with 90 kg of standard bitumen B200, 10 kg of phenolic resin (Viaphen PA101 from Vianova) and 5 kg of epoxy resin (Epotuf 37-140 from Reichhold Chemie AG ) and a temperature of 80 to 90 ° C stirred. The mixture is then heated to 100-110 ° C. for 1 hour. The mass contained is also very dimensionally stable, thermally resilient and leach-resistant.

Example 9:

An ion exchange resin mixture of unknown provenance, loaded with partially volatile pollutants such as Hg and Se ions, is treated in a paddle mixer at 80 ° C. Then an embedding compound of 70 ° C. with 57% by weight of standard bitumen B80, 30% by weight of raw montan wax, 11% by weight of epoxy resin (Shell Epon 828) and 2% by weight of butylene glycol diglycidyl ether is added, with a viscous paste paste is formed. Mixing is continued for 1 hour at 70 ° C, binding volatile reactive amines, after which the mixture is filled into barrels. To improve the mechanical properties, additives, as mentioned in Example 3, can be added.

The products produced according to Examples 1 to 4 and 7 to 9 can be removed after the system has been aerated and, just like the products produced by stirring in Examples 5 and 6, represent a stable, largely leach-resistant, non-gassing, homogeneous block after cooling. If such a block is split mechanically, the fracture surface shows a completely homogeneous image and no odor pollution from volatile amines can be detected.

The products or compositions obtained in this way are outstandingly suitable for long-term storage and can also be recycled at a later point in time, if necessary, for the pollutants contained therein.

Claims (17)

1. A process for the transformation of mixtures, in particular those containing toxic substances, containing anion exchange resins containing amines, preferably free reactive amines and/or anion exchange resins emitting such amines, into a state suitable for intermediate storage or final storage by means of thermal treatment, characterized in that the anion exchange resins or the mixtures containing them are heated in the presence or in contact with water and a substance of alkaline reaction at least up to the onset of decomposition of the anion exchange resins and release of the amines and that the substantially dry mass formed in the process is filled into a container for intermediate or final storage.
2. The process according to claim 1, wherein the medium in which the anion exchange resins or the mixtures containing them are present is adjusted to a pH value of at least 9.
3. The process according to claim 1 or 2, wherein the anion exchange resins or the mixtures containing them are heated in thin layers.
4. The process according to any one of the claims 1 to 3, wherein an embedding substance is introduced into the container intended for filling.
5. The process according to any one of the claims 1 to 4, wherein the anion exchange resins or the mixtures containing them are heated quickly, preferably in less than five minutes, preferred in less than two minutes, in particular in less than fourty seconds, to a temperature of less than 280°C, preferably between 110°C and 270°C, preferred between 140°C and 250°C, in particular to about 210°C.
6. The process according to any one of the claims 1 to 5,wherein the heating and optionally the filling into the container and the embedding are effected at a pressure below ambient pressure, preferably at 50 to 300 mb, in particular at 120 to 180 mb, absolute.
7. The process according to any one of the claims 1 to 6, wherein the substantially dry mass formed is introduced into, and allowed to settle sedimentatively, preferably under the action of its own weight, into a liquefied, high-molecular organic embedding mass with at least one bitumen containing an amine-hardening polymer or other amine-binding organic compound and/or tall oil pitch and/or substantially non-amine-hardening polymer.
8. The process according to any one of the claims 1 to 7, wherein the substantially dry mass formed is introduced into a liquefied embedding mass, preferably a bitumen melt, whose temperature is maintained lower than the temperature on heating the anion exchange resins or mixtures containing them, in particular at 120 to 210°C, preferably at 160 to 190°C and that optionally, the temperature of the embedding mass is raised after completion of the embedding operation to a temperature which is higher than the embedding temperature.
9. The process according to any one of the claims 1 to 8, wherein the amines or the vapors containing them released on heating the anion exchange resins or the mixtures containing them are brought into contact with, preferably made to pass through, an aqueous solution of at least one acid which is optionally at least partially an acid whose amine salts are biodegradable, preferably citric acid and/or tartaric acid and/or acetic acid, preferably at a pressure of less than ambient gas pressure and a pH value of at most 4.
10. The process according to any one of the claims 1 to 9, wherein the gases and/or vapors formed by contacting the amines or the vapors containing them with the solution of at least one acid are subsequently brought into contact with an alkaline solution.
11. The process according to any one of the claims 4 to 10, wherein the substantially dry mass formed is introduced into an embedding mass whose basic mass contains bitumen and/or paraffin and/or tall oil pitch, preferably bitumen, at least 0.5 percent by weight, preferably at least 2 percent by weight, of reactive, amine-binding additives, preferably epoxide compounds, in particular glycide and/or epoxide resins, and/or preferably organic acid anhydrides,in particular dodecenyl succinic acid anhydride, and/or reactive phenolic resins, preferably in dissolved form.
12. The process according to claim 11, wherein the reactive amine-binding additives are contained in total amounts of at most 50 percent by weight, preferably at most 30 percent by weight, each in relation to the basic mass.
13. The process according to claim 11 or 12, wherein the embedding mass contains, each in relation to the basic mass, 2 to 30 percent by weight, preferably 5 to 20 percent by weight, of epoxide resins or 0.5 to 30 percent by weight, preferably 1 to 20 percent by weight, of low-molecular epoxide compounds, preferably glycides, preferred butyleneglycol diglycide ether.
14. The process according to any one of the claims 11 to 13, wherein the embedding mass contains, each in relation to the basic mass, 0.5 to 20 percent by weight, preferably 1 to 15 percent by weight, of acid anhydride, preferably dodecenyl succinic acid anhydride.
15. The process according to any one of the claims 11 to 14, wherein the embedding mass contains, each in relation to the basic mass, 2 to 50 percent by weight, preferably 5 to 30 percent by weight, of phenolic resin.
16. An apparatus for carrying out the process according to any one of the claims 1 to 15, having a heating and drying means and a means for aspiring of gases and/or vapors from the heating and drying means at a pressure below ambient gas pressure, the heating and drying means being connected to at least one means for evacuating gases and/or vapors formed therein, characterized in that a reactor (8) with a preferably aqueous solution of a preferably biodegradable acid and accessible for flow of the gases and vapors containing amines released on heating anion exchange resins or mixtures containing them is arranged between the heating and drying means (2) for the anion exchange resins of alkaline adjustment and the aspiration means (11) and that the heating and drying means (2) is provided with an outlet lock (3) leading to a container (6).
17. The apparatus according to claim 16, wherein a further reactor (9) with a liquid medium of alkaline reaction is arranged upstream or downstream of the aspiration means (11), the aspiration means (11) preferably being an ejector pump charged with a jet of medium taken from the reactor (9).

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