JPS6120839B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for the environmentally friendly final storable solidification of concentrated liquid wastes or fine solid wastes suspended in water containing high or intermediate levels of radioactivity and/or actinides. The concentrated waste liquid or suspension is subjected to ceramic sintering together with absorbent and/or hydraulically bondable inorganic materials to form a solid sintered body. It has already been proposed for some time to reduce the volume of radioactive liquid waste in order to solidify it. This process involves concentrating the radioactive material and subjecting it to a heat treatment with glass-forming agents to distribute the radioactive material into a glass melt, which is then processed into a solid material by condensation, or a silicate-containing clay or It is mixed with an ion exchanger and fired into a solid ceramic. A disadvantage of producing glass blocks containing radioactive waste is that very complex and expensive equipment is required, which must be operated by skilled personnel. Furthermore, the permanent release of radioactivity and thermal energy by the encapsulated high-level radioactive materials can cause the glass structure to disintegrate during long-term storage processes, which is the case in the case of intact glass block waste. would significantly reduce the quality with respect to relatively good leachability. A disadvantage of the calcination treatment of mixtures of clay and radionuclides according to the known technology is that the quality of the solidified product with a high concentration of radioactive content does not meet the requirements placed on the final storable product. Another disadvantage of the consolidation process to glass and calcined clay is that a significant amount of radioactive material is vaporized from the unconsolidated waste during the high-temperature treatment process, so solid filters, condensation separators and washing columns are not required. This must be recovered using expensive waste gas purification equipment. The mixing of aqueous atomic scraps with refractory cement and the subsequent solidification of the hardened block by ceramic firing into a leaching-resistant solid sintered body has been proposed by R. Alberti (West German Patent No. 1127508). Specification). To increase the mechanical strength of the hardened blocks, it has been recommended to add refractory aggregates to the refractory cement, such as shamots or brick chips. For example, a cylindrical compact is produced from molten alumina cement and a radioactive liquid, which is uniformly heated to a temperature of up to 500°C within 5 hours after hardening to evaporate excess water and then rapidly heated, e.g.
The firing temperature was set to 1100°C and maintained at this temperature for about 2 to 4 hours, after which the compact was gradually cooled. However, Alberti does not mention the radioactivity of the solidified radioactive liquid in the patent specification. Similarly, the specification hardly describes the amount of liquid contained in the three containers or the water-cement value. Furthermore, no leaching experiment results are disclosed. Although the Alberti process can be used to solidify low-level radioactive liquid wastes if desired, this process is extremely expensive and unnecessarily complicated. Also, this method cannot be used to solidify liquid wastes that are highly or moderately radioactive and/or actinide-containing. In addition to cement or concrete, medium-level radioactive waste is also solidified into bitumen at temperatures above 150°C. Cement solidification and bituminous processing lead to end products with low thermal stability and very low long-term radiation stability, the intermediate and final storage of which requires particular safety precautions. For the solidification of actinide concentrates, bitumen, cement or concrete solidification methods are not particularly suitable, since the radiolysis of the actinides results in significant gas evolution and heat is generated within the product as a result of the radioactive decay of the actinides. do not have. Conventionally, suspended combustion or ion exchangers were cemented in containers and the thus coated solidified product was directly stored. However, the properties of this type of block, especially the mechanical stability and leaching stability, are not particularly good, so that this type of consolidation mode can only be used for low-level radioactive wastes. The object of the present invention is to provide high and medium level radioactive and actinide-containing solidified products whose solidified products do not have the disadvantages of hitherto known solidified products and which, due to their special properties, satisfy all the conditions regarding final shelf life. The object is to obtain a method for solidifying liquid waste and/or suspended powder solid waste. This purpose, according to the invention, is achieved by: a. By evaporating the concentrated waste liquid or suspension, its water content is reduced by metal ions and/or
The amount of metal oxide to be formed is 10 to 30 of the concentrate (B)
The solidified content (weight%) is adjusted to 40 to 80% by weight, and the PH value of the concentrate (B) is adjusted to 5 to 10 with a known reagent, and the concentrate obtained from b a) is B) with or without additives to suppress the volatile content of alkali metals or alkaline earth metals and the volatile content of degradable anions selected from the group of sulfuric acid, phosphoric acid, molybdate and uranate ions. a clayey matrix containing cement or an additive to suppress the volatile content of alkali metal or alkaline earth metal volatiles and decomposable anions selected from the group of sulfuric acid, phosphoric acid, molybdate and uranate ions. Mixing the clay matrix and the concentrate (B):clay matrix at a weight ratio of 1:1 to 2:1, c) Producing a molded body from the soft mass obtained from b), and d) Producing the molded body from room temperature. Drying at temperatures between up to 150°C, calcining at temperatures up to 800°C, followed by 800°C
heat treatment, including calcination at temperatures of up to 1400°C to form an actually insoluble mineral phase;
~10 mm) with a dense, continuous ceramic or metallic matrix is achieved by each processing step. In an advantageous embodiment of the process of the invention, the concentrate (processing step b) is mixed with 10 parts by weight of clayey matrix and cement (20-30% by weight of SiO ₂ and 40-70% by weight of CaO).
After producing a molded body from this soft mass (processing step c), but before heat treatment (processing step d), the molded body is hardened and subsequently Superficial decontamination with water is carried out. The clay matrix advantageously contains SiO ₂ in the range 45-70% by weight and Al ₂ O ₃ in the range 15-40% by weight, with an ignition loss of 5-15% by weight. As the clay substrate, one or more substrates selected from the group of china clay, stoneware clay, china clay mixture and kaolin can be used. Additives to suppress alkali metal and alkaline earth metal volatiles are added to 20 parts by weight of clay substrate.
1 to 3 parts by weight of TiO ₂ powder or 1 to 5% by weight of TiO ₂ based on the soft mass obtained from process step b). Additives to suppress sulfate volatile matter are BaO1-5
additives to suppress phosphate volatiles consisting of 2 to 10% by weight of MgO or BeO or crushed natural beryl
% by weight, each of which consists of treatment step b)
These are the values for soft lumps obtained in . The continuous matrix covering the compacts or fragments (processing step e) is a cement made from at least one cement selected from the group of portland cement, slag cement, blast furnace cement, truss cement, oil shale cement and alumina cement. Made of brick, or made of china clay, stoneware clay,
at least one clay matrix selected from the group of china clay mixtures and kaolin, and at least one cement selected from the group of portland cement, slag cement, blast furnace cement, truss cement, oil shale cement, and alumina cement,
It consists of calcined ceramic made with a clayey matrix:cement weight ratio of 10:1 to 4:1. To further improve the thermal conductivity, the continuous matrix may consist of a copper-zinc alloy, a copper-tin alloy, lead or a lead alloy containing more than 50% by weight of lead. If the continuous matrix does not consist of metals or alloys, the setting of the matrix-waste mixture can be dispensed with by ceramic calcination, optionally carried out under pressure. Adjustment of the PH value of the concentrate (B) can be carried out by adding strongly alkaline solutions or by denitration with known reagents, for example formic acid or formaldehyde. Drying and/or advantageously from process step d)
The calcination process is controlled (adjusted) by means of a temperature-time program depending on the water and NO content of the air stream coming from the furnace, i.e. the respective temperature is adjusted according to the non-negligible water and NO content of the waste air stream. maintain until no longer observed, or increase temperature very slowly. For example, during the reprocessing of nuclear fuel, the production and processing of nuclear fuel, as well as from other nuclear processing equipment, the following radioactive wastes arise which can be solidified in particular with the method of the invention: 1. High-level waste liquid: This is a nitric acid solution consisting mainly of heavy metal nitrates, produced during the separation of separation products from spent nuclear fuel. 2. Medium level effluent: This is a predominantly nitric acid solution, generally containing a high degree of sodium nitrate, which is produced during the reprocessing of nuclear fuel and the decontamination of nuclear processing units. 3 Actinide concentrates: These are solutions, powders or combustion residues obtained as waste products, especially during the processing and production of nuclear fuels. 4 Ash and residue resulting from the combustion of organic radioactive waste. The concentration treatment of the concentrate (B) by evaporation treatment, which can be performed before and/or after the pH value adjustment (processing step a), is carried out to the extent that a fluid concentrate can be obtained. The radioactive concentrate thus pretreated is transferred to a mixer or muller and is stirred and homogenized into a thick slurry by adding a dry mixture of aggregates consisting primarily of clay matrix. The aggregate mixture consists of the main components kaolin, clay, china clay and/or quartz powder and advantageously the secondary component cement. The mixing ratio of the substance contained in the radioactive concentrate and the aggregate mixture is such that a shape-stable molded body containing approximately 50% by weight of water can be produced from the slurry material, and the next molded body After drying and calcination, the chemical composition is chosen in such a way that a final product is obtained whose chemical composition corresponds to a natural stable mineral or rock. The aggregate mixture may contain from 7 to 20% by weight of cement based on the sum of clay matrix and cement. The addition of cement results, after complete hardening, in a shape-stable molding upon treatment with water. This advantage is useful when water-washing away water-soluble salts that build up or blow out on the surface of the molded body during the subsequent drying process. Wash water is supplied to the radioactive solution again at the beginning of the process. Another advantage is that the degree of mechanical hardening of the molded body is improved in view of further processing steps. The slurry product is processed into shaped bodies by pressing the product in a mold or directly, for example in an extruder. When manufactured in a mold, the product remains in the mold until its shrinkage allows it to be easily removed. The moldings are preferably dried at room temperature in a stream of air; for cement-containing products, 30 days are required for complete hardening. Next, the molded body is further dried in a drying oven while increasing the temperature. At this time, the nitrates contained are also thermally decomposed. The heating program is highly dependent on the chemical composition of the shaped body and its size. In the temperature range from room temperature to 150°C, several hours are required to remove the chemically unbound water. Chemically bound water is removed over a temperature range of about 150°C to about 800°C, and metal nitrates are thermally decomposed to metal oxides and nitrogen oxide-containing gases in this temperature range. In this case, the thermal decomposition of nitrates, which are present in higher concentrations, should be taken into account. That is, the heating rate is kept correspondingly low at a specific decomposition temperature, or primarily a stop point is set in the heating program. The heating program can be controlled and regulated in a simple manner by means of a continuous quantitative measurement of the concentrate uptake in the concentrate separator for the reactor waste gas and by continuous monitoring of the concentration profile of the nitrogen oxide-containing gases in the reactor waste gas. This is done via quantitative measurements. Furthermore, the reactor waste gas is purified using dilute nitric acid to absorb nitrogen oxide-containing gases in a washing column.
This washing liquid as well as the concentrate from the condenser connected upstream of the washing column are evaporated in an evaporator.
The distillate is reprocessed as low-level waste, which is not the subject of the process of the invention. The concentrate from the evaporator is fed back to the first stage. After reaching a maximum transition temperature of about 800° C. in the drying oven, the shaped body is fired in a sintering oven to the desired final product.
Drying and firing can also be carried out in the same oven.
The firing process is carried out at a temperature of 1100℃ to approximately 1400℃,
In this case, the molded body shrinks considerably. Depending on the size of the compact, care should be taken to carry out the calcination process sufficiently slowly to avoid cracks and voids in the final product. The best calcination temperature and time must be adapted to the composition of the respective product. Place the single sintered body into a metal container. If high levels of radioactive heat of decomposition occur, the space between the sintered body and the metal container can be filled with a better heat conducting material such as cement or a low melting point metal or alloy such as lead, bronze, etc. The metal container is also the final storage container for radioactive waste solidified in ceramic. According to another method of the invention, the concentrate (B) and a small amount of cement or alkali metal or alkaline earth metal volatiles and decomposition selected from the group of sulfuric acid, phosphoric acid, molybdate and uranate ions A molded body is produced by spraying the concentrate (B) onto the clay matrix present on a moving pelletizing plate. Pelletizing can be carried out completely continuously and without any problems. Since in this case the pressing of the mudd compound is omitted, the method is suitable for incorporating further additives into the cement-clay mixture, such as cement fillers (e.g. barium silicate hydrate) or others. It's advantageous. Compared to previously known methods of solidifying high-level waste liquids, such as in glass matrices, the method of the invention has a number of distinct advantages. For example, in the method of the invention, the primary solidification already takes place at room temperature, so that the subsequent drying and calcination only need to remove the radioactivity from the surface of the solidified product. In this case, the product acts as a filter during high-temperature processing. The known method requires expensive processing equipment with remote control equipment in hot cells or alpha-tight cells.
In contrast, in the method of the present invention, processing is performed using extremely simple equipment that has minimal construction costs and is compatible with the working conditions for handling radioactive materials. Furthermore, the method according to the invention has the advantage that the very difficult problems that arise when melting glass can be avoided. The products produced by the process of the invention are stable at temperatures above 1000° C. and, due to their chemical nature, do not generate radiolysis gases.
Therefore, it is also possible to highly concentrate actinides and solidify them in a ceramic matrix. This is because the properties of the final product suitable for final storage are not adversely affected by the generation of alpha radiation or radiolysis gases resulting from high storage temperatures. Another advantage of the process of the invention is that the product is highly adaptable to changes in the chemical and physical properties and composition of radioactive waste. Next, the present invention will be described in detail based on Examples, but the present invention is of course not limited to these. Example 1 The chemical composition of high-level liquid waste generated during the reprocessing of spent fuel from a light water reactor with a burnup of 3300 MWd per ton of fuel was simulated using chemically similar inert isotopes for its main components. . This nitric acid waste solution was denitrated by boiling it with formic acid until the pH value was adjusted to 2.5. The solution was then adjusted to a pH value of 6 by addition of 1M caustic soda and concentrated by distillation. The solution or suspension after this pretreatment had the following chemical composition. a Water content: H ₂ O 700g b Residual nitrate content: NO ₃ 109g c Burning residue: Gd ₂ O ₃ 91.2g ZrO ₂ 35.0g MoO ₃ 36.5g Na ₂ O 23.4g BaO 18.8g Ag 28.5g MnO ₂ 8.0g Te 4.0g Pb ₃ O ₄ 12.8g Fe ₃ O ₄ 20.8g Cr ₂ O ₃ 3.7g NiO 3.2g Total 285.9g The solution or suspension was mixed with Portland cement and Hirschauer kaolin (Hirsc-
The slurry was made into a slurry with a mixture of Kaolin (weight ratio: 1:8). In this case 981 g of the mixture were used. A molded body with a diameter of 25 mm and a height of approximately 20 mm was produced by extruding the slurry soft mass into a tube. Similarly, cylindrical molded bodies with diameters of 80 mm and 80 mm were produced using polyethylene beakers. This was able to be removed after 3 days as a result of the soft lump shrinking. All moldings were dried in air for 20-30 days, subsequently washed with water, dried in an oven at elevated temperature, calcined and fired. The furnace heating program is shown in the table below.

Table: The calcined final product is characterized by high hardness (Mohs hardness 6-7) and low solubility in water. The water solubility at room temperature is less than 1 cm ² of surface area and 10 ⁻⁶ g of product per day. The chemical composition of the product is then indicated.

【table】

[Table] The stoichiometry of the sintered body of this final product almost corresponds to that of anorthite or nepheline, which are known as extremely stable naturally occurring minerals. Example 2 Medium-level effluents produced during nuclear fuel reprocessing contain up to 90% sodium nitrate as salt ballast. Therefore, in order to perform a reproducible simulation of this type of waste, the sodium nitrate solution was mixed with a mixture of cement and kaolin (1:10 by weight).
It turned into mud. Its chemical composition is clear from the deputy chief. Simulated waste liquid: 184 g NaNO ₃ Water 300 g Portland cement: 50 g Geisenheimer Kaolin: 500 g Molding compositions were produced in accordance with Example 1 by extrusion and by molding. Air drying and water washing were performed as described in Example 1. The heating program for drying, calcining and firing the compact is shown in the table below.

Table: The final calcined product has a hardness of 5 to 6 on the Mohs scale. The water solubility at room temperature is 1 cm ² surface area and approximately 10 ^-6 g of product per day. The chemical composition of the final sintered product is then indicated.

[Table] The stoichiometry of this final product sintered body almost matches that of nepheline, which is known as a naturally occurring extremely stable mineral. Example 3 Actinide concentrates produced as radioactive waste during the production of plutonium-containing fuels are concentrates or combustion ash produced during the combustion of organic materials. Actinide concentrate is a relatively short-lived plutonium isotope Pu ²⁴¹ as a radioactive component.
contains relatively large amounts of plutonium and americium, which are produced during the radioactive decay of Packing this actinide concentrate into ceramic matrices presents no problems. This is because the chemical nature of the waste components is similar to the scorching residue of the high level effluent listed in Example 1. A suspension of 2.94 g of americium dioxide powder in 7 g of water was slurried with 10 g of a mixture of Portland cement and Hirschauer kaolin (1:10 weight ratio). Extrude the slurry soft mass through a polyethylene pipe with a diameter of 20 mm.
A cylindrical molded body with a height of 33 mm was manufactured. The molded body was dried at room temperature for 10 days. Moldings were prepared in a similar manner, but without americium dioxide, from 7 g of water and 10 g of a mixture of Portland cement and Hirschauer kaolin (weight ratio 1:10) and likewise dried for 10 days at room temperature. . Both molded bodies had a volume of 28% after drying compared to the initial volume at the time of manufacture.
It showed the same volume reduction of ±2%. This fact indicates that the generation of radiolysis gas and decomposition heat do not affect the manufacturing process. The AmO ₂ -containing moldings were dried and calcined in an oven at elevated room temperature according to the heating program described below.

Table: After calcination, a product was obtained which corresponded in terms of its stoichiometry to anorthite or nepheline. The weight loss of the sintered product when leaching with water at room temperature is 1 cm ² of surface area and 1
Less than 10 ^-7 g per day. The chemical composition of the sintered product is shown in the table below.

[Table] The α-specific radioactivity of the sintered body is 715 mCi/g,
The specific heat of decomposition is approximately 22 mW/g. Example 4 Organic radioactive waste generated during the preparation of plutonium-containing fuels is concentrated not only by dry combustion in atmospheric oxygen but also by wet combustion treatment. One of these treatment methods is to process organic waste in concentrated sulfuric acid at 200°C.
This is carried out by carbonization at a temperature above and subsequent oxidation of the carbon using a chemical oxidizing agent such as nitric acid. In this case, a combustion residue containing a large amount of sulfate is produced. The residue, especially after neutralization with caustic soda, has a high content of sodium sulfate as well as sodium chloride resulting from the combustion of polyvinyl chloride. In Example 2, the sodium nitrate solution was inside the sintered body,
It was shown that it can be solidified through chemical bonds that correspond to the stoichiometric nature of nepheline, a naturally occurring mineral. Additionally, sodium sulfate solutions and sodium nitrate solutions containing sodium chloride can be cured in a similar manner, but in this case the absorption capacity of nepheline is 14% by weight for sodium sulfate and 12% for sodium chloride. % by weight. The crystalline phases produced at this time correspond to the natural stable minerals larvae (containing sodium sulfate) and balataite (containing sodium chloride). Example 5 Using a laboratory pelletizing device (its pelletizing pan is 40 cm in diameter and installed at an angle of inclination of 46°), at a rotational speed of 26 rpm, 1 kg of Portland cement containing approximately 10% bentonite and a MAW of the following composition: - Granules or pellets approximately 1 cm in diameter were produced from 230 g of the simulated solution.
It took about 20 minutes to implement. Composition of MAW-Concentrate-Simulate Solution NaNO ₃ 450.0 g/ NaNO ₂ 5.0 〃 Fe (NO ₃ ) ₃ 0.1 〃 Ni (NO ₃ ) ₂ 0.01 〃 Cr (NO ₃ ) ₃ 0.01 〃 Ca (NO ₃ ) ₂ 0.15 〃 Mn(NO ₃ ) ₂ 0.02 〃 Sr(NO ₃ ) ₂ 0.002 〃 Mg(NO ₃ ) ₂ 0.2 〃 Ce(NO ₃ ) ₄ 0.02 〃 Al(NO ₃ ) ₃ 0.03 〃 Tributyl phosphate 0.2 〃 Dibutyl phosphate 0.1 〃 Kerosene 0.02 Sodium oxalate 10.0 Sodium tartrate 10.0 NaF 2.0 Detergent 2.0 CS 0.004 P (as NaHPO ₄ ) 0.2 HNO ₃ (~1 m) was added to the solution. before solidification
The pH was adjusted to 8.5-9 with NaOH. The desired charge of waste liquid to be solidified can be adjusted by selecting the diameter of the pelletizing dish.

Claims (1)

[Scope of Claims] 1. Metal ions in the form of ceramic firing of concentrated waste liquid or suspension together with absorbent and/or hydraulically bondable inorganic materials to form a solid sintered body. and/or high- and medium-level radioactive concentrated liquid waste containing metal oxides, actinide-containing concentrated liquid waste or suspensions of fine solid waste suspended in water to an environmentally friendly final stage. (a) reducing the water content of the concentrated waste liquid or suspension by evaporating it so that the amount of metal ions and/or metal oxides is 10 to 10% of the concentrate to be formed; 30% by weight
(b) A very small amount of the concentrate obtained from treatment step (a) additives to suppress alkali metal or alkaline earth metal volatiles that may be present in the cement matrix or concentrate and/or selected from the group of sulfuric acid, phosphomolybdic acid and uranate ions. A mixture of a small amount of cement and a clayey matrix containing an additive to suppress degradable anion volatiles is mixed at a weight ratio of concentrate to clayey matrix of 1:1 to 2:1, with the clay (c) producing a shaped body from the soft lump obtained from the treatment step (b); (d) The compact is dried at a concentration from room temperature to 150°C, calcined at a temperature from 150°C to 800°C, and then calcined at a temperature from 800°C to 1400°C to form a naturally occurring stable mineral or rock. (e) forming a practically insoluble mineral phase of approximately corresponding chemical composition; (e) covering the entire body of the calcined mineral phase with a dense and continuous ceramic or metallic matrix; A method for solidifying radioactive waste characterized by: 2. A method according to claim 1, characterized in that the molded bodies of process step (d) are ground to a particle size of 1 mm to 10 mm before being coated with the matrix of process step (e). 3. Mixing in treatment step (b) is carried out with a mixture of 10 parts by weight of clayey matrix and 1 to 2 parts by weight of cement containing 20 to 30% by weight of SiO ₂ and 40 to 70% by weight of CaO. 2. A process as claimed in claim 1, characterized in that the shaped bodies of c) are hardened before the treatment step (d) and are subsequently superficially decontaminated with water. 4. The clay matrix contains SiO ₂ in the range of 45-70% by weight and Al ₂ O ₃ in the range of 15-40% by weight, and 5.
A method according to claim 1, characterized in that it exhibits an ignition loss in the range of -15% by weight. 5.Additives that suppress alkali metal and alkaline earth metal volatile matter are added to 20 parts by weight of clay substrate.
2. A method according to claim 1, characterized in that it comprises 1 to 3 parts by weight of TiO ₂ powder. 6. Claim No. 6, characterized in that the additive for suppressing alkali metal and alkaline earth metal volatiles consists of 1 to 5% by weight of TiO ₂ based on the soft mass obtained from treatment step (b). The method described in Section 1. 7 Additives that suppress sulfate volatile matter are added to the treatment process.
The method according to claim 1, characterized in that it comprises 1 to 5% by weight of BaO based on the soft mass obtained from step (b). 8 Additives that suppress phosphate volatiles are added to the treatment process.
2. A method according to claim 1, characterized in that it comprises from 2 to 10% by weight of MgO based on the soft mass obtained from step (b). 9 Additives that suppress phosphate volatiles are added to the treatment process.
The method according to claim 1, characterized in that it consists of 2 to 10% by weight of BeO or crushed natural beryl based on the soft mass obtained from step (b). 10. Claim 1, characterized in that the continuous matrix consists of at least one cement selected from the group of Portland cement, slag cement, blast furnace cement, truss cement, oil shale cement, alumina cement, or mixtures thereof. The method described in section. 11 The continuous matrix is (1) china clay, stoneware clay,
at least one clay matrix selected from the group of china clay mixtures and kaolin; and (2) at least one cement selected from the group of portland cement, slag cement, blast furnace cement, truss cement, oil shale cement, and alumina cement. From seeds to clay matrix: cement weight ratio 10:1 to 4:
2. A method according to claim 1, characterized in that the ceramic is made of a fired ceramic produced in accordance with claim 1. 12. A method according to claim 1, characterized in that the continuous matrix consists of a copper-zinc alloy. 13. A method according to claim 1, characterized in that the continuous matrix consists of a copper-tin alloy. 14. Process according to claim 1, characterized in that the continuous matrix consists of lead or a lead alloy containing more than 50% by weight of lead. 15 Claim 1 characterized in that the PH value of the concentrate is adjusted by adding a strong alkaline solution.
The method described in section. 16. The method according to claim 1, characterized in that the pH value of the concentrate is adjusted by denitration. 17. The method according to claim 16, characterized in that the denitration is carried out with formaldehyde. 18. The method according to claim 1, characterized in that the pH value of the concentrate is adjusted by denitration with formic acid. 19 Measure the water _{and NO} A method according to claim 1, characterized in that the temperature is adjusted. 20. Claim 1, characterized in that the mixing of the concentrate and the clay matrix and the production of the molded body are carried out by spraying the concentrate onto the clay matrix present on a moving pelletizing pan. the method of. 21 Metal ions and/or metal oxidation in the form of ceramic firing of the concentrated waste liquid or suspension with absorbent and/or hydraulically bondable inorganic materials to form a solid sintered body. Solidification of high- and medium-level radioactive concentrated liquid wastes containing substances, actinide-containing concentrated liquid wastes or suspensions of fine solid wastes suspended in water for environmentally safe final storage. (a) reducing the water content of the concentrated waste solution or suspension solution by evaporation so that the amount of metal ions and/or metal oxides is between 10 and 30% by weight of the concentrate to be formed;
(b) The concentrate obtained from treatment step (a) is adjusted to 40 to 80% by weight with respect to the solids content, and the pH value of the concentrate is adjusted to 5 to 10. additives to suppress alkali metal or alkaline earth metal volatiles that may be present in the mixture and/or additives to suppress decomposable anionic volatiles selected from the group of sulfuric acid, phosphoric acid, molybdate and uranate ions. admixture with a clay matrix containing the agent in a concentrate:clay matrix weight ratio of 1:1 to 2:1, where the clay matrix is selected from the group of china clay, stoneware clay, china clay mixture and kaolin. (c) producing a shaped body from the soft mass obtained from processing step (b); (d) drying the shaped body at a temperature between room temperature and 150°C; calcination at a temperature of up to 800°C and then calcination at a temperature of 800°C to 1400°C to form a virtually insoluble mineral phase having a chemical composition approximately corresponding to a naturally occurring stable mineral or rock; (e) A method for the solidification of radioactive waste, characterized in that it consists of a treatment step in which a compact consisting of a calcined mineral phase is completely coated with a close and continuous ceramic or metallic matrix. 22. Claim 21, characterized in that the mixing of the concentrate and the clay matrix and the production of the molded body are carried out by spraying the concentrate onto the clay matrix present on a moving pelletizing pan. the method of.