CN111039674B

CN111039674B - Gadolinium zirconate ceramic for solidifying TRPO simulation waste and preparation method thereof

Info

Publication number: CN111039674B
Application number: CN201911340676.4A
Authority: CN
Inventors: 卢铁城; 张宇彤; 黄章益; 李秋瑶; 齐建起
Original assignee: Sichuan University
Current assignee: Sichuan University
Priority date: 2019-11-29
Filing date: 2019-12-23
Publication date: 2021-11-16
Anticipated expiration: 2039-12-23
Also published as: CN111039674A

Abstract

The invention discloses gadolinium zirconate ceramic for solidifying TRPO simulation waste and a preparation method thereof, wherein the preparation method comprises the following steps: (1) preparing precursor powder by solid dissolving radioactive elements in a liquid mode; (2) preparing the precursor powder obtained in the step (1) into a biscuit by adopting dry pressing; (3) the gadolinium zirconate ceramics for solidifying TRPO simulation waste is prepared by adopting a microwave sintering method, has the advantages of no cracking in block shape, high compactness and high hardness, and still keeps a single fluorite structure when the solid solution amount reaches 60 percent. The preparation method provides a basic reference scheme for realizing the treatment of high-level radioactive waste liquid, in particular the solidification of long-life actinides.

Description

Gadolinium zirconate ceramic for solidifying TRPO simulation waste and preparation method thereof

Technical Field

The invention belongs to the technical field of nuclear energy, relates to nuclear waste solidification, and particularly relates to gadolinium zirconate ceramic for solidifying TRPO simulation waste, and a preparation method and application thereof.

Background

Nuclear power is used as a green energy source, the development of the nuclear power is started in new spring, but the safe disposal of radioactive wastes in spent fuel generated by the nuclear power is a key problem for restricting the sustainable development of the nuclear power. As for spent fuels generated by nuclear power, it is common to process the spent fuels by a purex (plutonium uranium recovery by extraction) process, so that uranium and plutonium are extracted and then changed into High-level radioactive waste liquid (HLLW), which contains more than 95% of radioactive substances of spent fuels, including residual uranium and plutonium (0.25% -0.5%), Minor Actinides (MA), such as Np, Am, Cm, and long-life fissile elements. The other source of the high-level radioactive waste liquid is a production process of nuclear weapon material plutonium, wherein the natural uranium generates 239Pu after being irradiated in a reactor, part of fissile nuclide also generates radioactive fission products, and the high-level radioactive waste liquid is generated after waste is finally treated and uranium and plutonium are recycled. A considerable amount of the high-level discharge waste liquid of the production pile is accumulated in China. The high-level radioactive waste liquid has high radioactivity, strong corrosiveness and long-term harmfulness, and can bring fatal harm to human once being diffused to the biosphere.

Aiming at the problem of high level radioactive waste liquid, a mature method is internationally that a vitreous body is directly solidified and then is placed in a disposal warehouse of a geological layer and is isolated from a biosphere for 10 ten thousand years. However, the method of directly curing without volume reduction has a drawback in that the amount of curing is large, the space occupied in a disposal warehouse is large, and the economical efficiency is poor. At present, a more researched alternative method is to separate long-life actinides (Actinides, ans) and high heat release fission products (Fissionproducts, FPs) in high-level radioactive waste liquid, so that the large-proportion volume reduction of HLLW can be realized. In contrast, different separation methods are adopted in various countries, China mainly adopts a TRPO method with independent property rights invented by Qinghua university (30% of TRPO (trialkyl oxyphosphate)/kerosene is adopted as an extractant to extract high-level waste liquid HHLW), most of the separated waste liquid can be directly solidified by glass according to the medium-low level waste liquid, and in addition, a small part of the volume of the high-level waste liquid needs transmutation or solidification treatment. Separating small volume part of high level radioactive waste liquid by TRPO flow, and adopting the waste liquid containing back extraction agent (such as H)₂C₂O₄、Na₂CO₃Etc.) of HNO₃Back extracting the rare earth and the like from the solution; the high-level waste liquid after the back extraction separation comprises two parts, namely alpha waste containing An (wherein a small amount of nuclide with commercial value, such as Np, can be further extracted), and non-alpha waste containing FP (which can be further separated into a Cs waste stream and a Sr waste stream), and the compositions of various high-level waste liquids after the separation are shown in the following table 1.

TABLE 1 composition of various high level radioactive waste liquids after TRPO flow separation Table (g/L)

Note: REE is rare earth element, TRU is transuranic element; values in Cs waste stream as mass percent

Because the concentration of An or FP in a small part of high-level radioactive waste liquid separated by the TRPO process is very high, compared with HLLW treated by the PUREX process, the high-level radioactive waste liquid has higher radioactivity, greater biological toxicity and high heat release rate. If glass is used for curing, although the technology is mature and the cost is low, the long-time storage still has great safety hazards.

Researches show that the ceramic curing substrate can solve the potential safety hazard problem of a glass curing body due to the advantages of excellent radiation resistance, good chemical stability, large nuclide package capacity and the like. Different mineral phases may be used to solidify different high-level nuclides using ceramic solidification. A. the₂B₂O₇Ternary oxide of the system Gd₂Zr₂O₇Ceramics are known as an ideal ceramic curing substrate due to: (1) gd (Gd)₂Zr₂O₇The formation of cation inversion defects is low, the radiation resistance is excellent, and a crystalline structure can still be kept under 100 dpa; (2) two cations (Gd)³⁺And Zr⁴⁺) The position can be used for solid solution of actinide high-level nuclide, and the solid solution amount is large; (3) gd element can be used as neutron poison and absorbs decayThe neutrons in the process avoid critical reaction and have high safety. However, there is no current disclosure of using Gd₂Zr₂O₇Reports of ceramics achieving solidification treatment of TRPO waste are due to the fact that Gd is allowed to react with the addition of TRPO waste₂Zr₂O₇The crystal structure of the ceramic itself is changed, which not only generates a hetero phase but also causes Gd₂Zr₂O₇The radiation resistance of the ceramic is seriously affected, and the aim of solidifying TRPO waste cannot be achieved.

Disclosure of Invention

Aiming at the technical difficulty of the solidification treatment of the TRPO waste, the invention aims to provide gadolinium zirconate ceramic for solidifying TRPO simulated waste and a preparation method thereof so as to realize large-capacity solidification of the TRPO simulated waste at a lower temperature.

Another object of the present invention is to propose the use of the above method in solidifying TRPO waste.

The invention provides a preparation method of gadolinium zirconate ceramics for solidifying TRPO simulation waste, which comprises the following process steps:

(1) preparation of precursor powder

According to the mass percentage of 10-60% of TRPO simulation waste in the precursor powder and Gd₂Zr₂O₇Metering raw materials accounting for 40-90% by mass, and mixing metal oxide or nitrate soluble in nitric acid and Gd in TRPO simulated waste raw materials₂Zr₂O₇Mixing raw materials of zirconium nitrate and gadolinium nitrate (the molar ratio of zirconium ions in the zirconium nitrate to gadolinium ions in the gadolinium nitrate is 1: 1) in nitric acid to form a mixed solution, then preparing primary powder by adopting a citric acid combustion method, primarily grinding the primary powder, then carrying out primary heat treatment at 800-1000 ℃ to fully combust impurities, uniformly mixing powder obtained by the primary heat treatment with nitric acid-insoluble metal oxide in TRPO simulation waste raw materials, subsequently calcining the obtained mixture at 800-1000 ℃ for 4-6 h for secondary heat treatment, and grinding and sieving the product obtained by the secondary heat treatment to obtain precursor powder;

(2) preparation of a biscuit

Dry-pressing the precursor powder obtained in the step (1) to prepare a biscuit;

(3) preparation of cured body ceramics

And (3) heating the biscuit prepared in the step (2) to 1100-1400 ℃ by adopting a microwave sintering method, preserving the temperature for 20-40 minutes, and then cooling to room temperature to obtain the gadolinium zirconate ceramic for solidifying TRPO simulation waste.

In the preparation method of the gadolinium zirconate ceramic for solidifying TRPO simulation waste, in the step (1), carbon element and nitrogen element in the mixed solution are decomposed in a gas form by a citric acid combustion method to obtain fluffy and dry primary powder (xerogel); grinding the primary powder, and then fully burning chlorine and nitrogen in the powder through primary heat treatment to remove impurity particles in the powder; and then the crystal phase is more uniform through the second heat treatment. The purpose of grinding is to fully mix the powder sample to obtain powder with better dispersibility and smaller particles. Thus, in order to achieve the above-mentioned objects, the skilled person can reasonably select the citric acid combustion process parameters step, the milling parameters and the heat treatment parameters according to common knowledge. The preferred citric acid combustion method comprises the following specific steps: adding citric acid into the mixed solution, stirring to completely dissolve metal oxides or nitrates which are soluble in nitric acid in the TRPO simulated waste raw materials, and heating the mixed solution to 250-300 ℃ for presintering for 4-6 hours to obtain primary powder; the citric acid is metered according to one citrate ion complexed with three univalent cations, and the invention is characterized in that Gd is contained in the precursor powder₂Zr₂O₇The citric acid is taken as 100wt percent to measure the citric acid, and the citric acid and Gd₂Zr₂O₇In a molar ratio of 14: 3, to ensure that the citrate ions complex all the cations in the mixed solution. The time for carrying out the first heat treatment at 800-1000 ℃ after the primary powder is primarily ground is 3-4 h. The mixing of the powder obtained by the first heat treatment and the metal oxide insoluble in nitric acid in the TRPO simulated waste raw material is preferably performed by a ball milling mixing method, and the ball milling mixing method comprises the following specific steps: placing the primary powder and the metal oxide insoluble in nitric acid into a ball milling tank, performing ball milling for 20-24 hours by taking absolute ethyl alcohol as a medium,and (3) carrying out drying treatment after ball milling and mixing, wherein the preferable drying mode is that the mixture is placed in an electric heating constant-temperature air blast drying oven with the temperature of about 70 ℃ and is kept for 8-12 hours.

According to the preparation method of the gadolinium zirconate ceramic for solidifying TRPO simulation waste, the purpose of the step (2) is to obtain a biscuit sintered by ceramic, the biscuit is prepared by adopting a dry pressing forming process, specific process parameters of the dry pressing forming are not specially limited, and a person skilled in the art can reasonably select the parameters according to the conventional dry pressing forming process. The preferable dry pressing forming method comprises the following specific process steps: weighing the precursor powder prepared in the step (1) according to the amount, loading the precursor powder into a powder tablet press, applying axial pressure to the powder, maintaining the pressure for 3-5 min under the condition of 6-8 MPa, and pressing into a wafer; and then carrying out vacuum packaging by using a plastic packaging bag, finally putting the plastic packaging bag into hydraulic oil of a cold isostatic press, slowly applying pressure until the pressure reaches 250MPa, maintaining the pressure for 15-20 min, and reducing the pressure to obtain a biscuit.

The preparation method of the gadolinium zirconate ceramic for solidifying the TRPO simulation waste comprises the step (3) for preparing the gadolinium zirconate ceramic for solidifying the TRPO simulation waste, wherein the preferable sintering temperature range is 1300-1400 ℃. The microwave sintering utilizes electromagnetic waves with the frequency of 2.45GHz, so that the ceramic material generates current in an electromagnetic field due to the fact that the change of medium polarization lags behind the change of the electromagnetic field, internal dissipation occurs, the energy of the electromagnetic waves is converted into the kinetic energy and potential energy of particles in the material, the material is uniformly heated, and the blocky gadolinium zirconate ceramic for solidifying TRPO simulated waste with high density and high hardness and no cracking is prepared. The prepared gadolinium zirconate ceramic has the crystal grain size reaching the nanometer level and the density of about 4.0-7.0 g/cm³The maximum hardness can be up to about 1200 Hv. In the step (3), the temperature rising rate is 5-8 ℃/min, and the temperature reduction rate is 5-10 ℃/min. Further preferably, the temperature increase rate is maintained at 6 ℃/min (at 500 ℃ C.) or less and at 5 ℃/min (at 500 ℃ C.) or less, and the temperature decrease rate is maintained at 5 ℃/min.

The preparation method of the gadolinium zirconate ceramic for solidifying TRPO simulation waste is characterized in that the TRPO simulation waste is alpha simulation waste containing An. The alpha simulation waste containing An comprises the following element components, by weight, 3.80 parts of Y, 9.37 parts of Pr, 11.64 parts of Mo, 32.49 parts of Nd, 2.27 parts of Ru, 5.90 parts of Sm, 2.97 parts of Pd, 1.20 parts of Eu, 9.90 parts of La, 1.49 parts of Gd and 19.08 parts of Ce; the raw material of the alpha simulation waste containing An is oxide or nitrate of the elements.

As the radioactive elements are dissolved in a liquid manner at the early stage of the preparation method of the gadolinium zirconate ceramic for solidifying TRPO simulation waste, and the dissolved radioactive elements are the same as the radioactive elements of TRPO waste (such as alpha waste containing An) in high-level waste liquid, the solidification system of the TRPO simulation waste related to the method is similar to the high-level waste liquid actually containing the TRPO waste, and the method for solidifying the TRPO simulation waste can be directly applied to solidifying high-capacity TRPO waste. According to the method of the present invention, the process of solidifying TRPO waste comprises the steps of:

(1) preparation of precursor powder

According to the mass percentage of 10-60% of TRPO waste in the precursor powder and Gd₂Zr₂O₇Metering raw materials accounting for 40-90% by mass, uniformly mixing high-level radioactive waste liquid containing TRPO waste with a nitric acid solution of zirconium nitrate and gadolinium nitrate to obtain a mixed solution, then preparing primary powder by adopting a citric acid combustion method, primarily grinding the primary powder, then performing primary heat treatment at 800-1000 ℃ until impurities are fully combusted, then grinding the obtained mixture, continuously calcining at 800-1000 ℃ for 4-6 hours for secondary heat treatment, and grinding and sieving the product obtained by the secondary heat treatment to obtain precursor powder;

(2) preparation of a biscuit

(3) preparation of cured body ceramics

And (3) preserving the heat of the biscuit prepared in the step (2) for 20-40 minutes at 1100-1400 ℃ by adopting a microwave sintering method, and then cooling to room temperature to obtain the gadolinium zirconate ceramic for solidifying TRPO waste.

The detailed explanation of the above steps (1) to (3) is substantially the same as that of the previous method for preparing gadolinium zirconate ceramic solidifying TRPO mimetic waste, and will not be explained here.

Innovations in the inventionThe method is characterized in that radioactive elements are dissolved in a liquid manner in the early stage (the dissolved radioactive elements are the same as those of TRPO waste in the high-level radioactive liquid waste), so that the radioactive elements in the high-level radioactive liquid waste are conveniently and directly treated, and the nano precursor powder is formed. Furthermore, the invention adopts a microwave sintering method to carry out ceramic sintering so as to obtain Gd₂Zr₂O₇The solidified ceramic is beneficial to industrial mass production, the sintering temperature of the invention is 1100-1400 ℃, and the low-temperature sintering can prevent radioactive elements from overflowing. The ceramic solidified body is a polycrystalline material, wherein grain boundaries are areas for connecting grains and crystal grains, and are sources for influencing the radiation resistance of the solidified body. The size of the grain boundary area is mainly determined by the grain size of the material, and the smaller the grain size, the higher the grain boundary area, especially the smaller the grain boundary area is to the nanometer scale, and vice versa. The boundary of grain boundary and phase boundary can be used as a trap of irradiation induced point defect to effectively capture the absorption point defect, and the grain reduces the distance that the point defect can be diffused to the grain boundary, so that under the double action of high grain boundary area and short diffusion distance after the grain is nanocrystallized, the composite effect of gap atoms around the grain boundary and vacant sites is effectively promoted, thereby inhibiting the accumulation of the point defect and greatly improving the capability of the material for resisting irradiation damage. Gd prepared by adopting the preparation method of the invention₂Zr₂O₇The radiation resistance of the cured body ceramic is not affected because the crystal structure of the ceramic is not changed. In addition, the size of the obtained solidified ceramic grains reaches the nanometer level, so that the irradiation resistance of the ceramic material is improved.

Compared with the prior art, the gadolinium zirconate ceramic for solidifying TRPO simulation waste and the preparation method thereof provided by the invention have the following beneficial effects:

1. according to the invention, radioactive elements are solid-dissolved in a liquid mode at the early stage (the solid-dissolved radioactive elements are the same as those of TRPO waste in high-level radioactive waste liquid), and precursor powder for solidifying TRPO simulated waste is prepared by using a citric acid combustion method, the solid-dissolving mode of the radioactive elements can be used for conveniently and directly treating the high-level radioactive waste liquid with the radioactive elements, the prepared precursor powder has good dispersibility and small particles, the solid-dissolving amount can be effectively increased, the solid-dissolving amount of the prepared gadolinium zirconate ceramics TRPO simulated waste can reach 60%, and the gadolinium zirconate ceramics still keeps a single fluorite structure when the solid-dissolving amount reaches 60%;

2. the invention adopts dry pressing to prepare the biscuit, has the advantages of high production efficiency, less labor, low rejection rate and short production period, and is suitable for large-scale industrial production;

3. the microwave sintering method used in the invention utilizes the electromagnetic wave with the frequency of 2.45GHz, so that the ceramic material generates current due to the fact that the change of the medium polarization lags behind the change of the electromagnetic field in the electromagnetic field, internal dissipation occurs, the energy of the electromagnetic wave is converted into the kinetic energy and the potential energy of particles in the material, the material is uniformly heated, the prepared gadolinium zirconate ceramic for solidifying the large-capacity TRPO waste has the advantages of blocky non-cracking, high compactness and high hardness, and the process of the microwave sintering method is mature, thereby being beneficial to industrial batch production;

4. the gadolinium zirconate ceramic for solidifying TRPO simulation waste, which is prepared by the invention, has the advantages that the radiation resistance is not influenced because the ceramic crystal structure is not changed, and the grain size of the obtained solidified ceramic reaches the nanometer level, so that the radiation resistance of the ceramic material is promoted, and the gadolinium zirconate ceramic has good radiation resistance;

5. the preparation method of the gadolinium zirconate ceramic for solidifying TRPO simulation waste provides a basic reference scheme for realizing the solidification of high-level waste liquid, particularly long-life actinide nuclide.

Drawings

FIG. 1 is SEM pictures of the primary powder and the precursor obtained in example 5, wherein (a) is the SEM picture of the primary powder, (b) is the SEM picture of the precursor, and (c) is the SEM picture of the partial enlargement of the precursor₂、RuO₂·nH₂O, PdO ball milling and mixing to obtain product;

FIG. 2 is an XRD pattern of precursor powders prepared in comparative example and examples 1-6, wherein x is the mass percentage of TRPO simulated waste;

FIG. 3 is an SEM image of cross sections of samples of gadolinium zirconate ceramics prepared in comparative example and gadolinium zirconate ceramics prepared in examples 1-6 for solidifying TRPO simulation waste, wherein x is the mass percent of TRPO simulation waste and 1100 ℃, 1200 ℃, 1300 ℃ and 1400 ℃ are four microwave sintering temperatures;

FIG. 4 is a plot of the relative density of gadolinium zirconate ceramics made by comparative example and gadolinium zirconate ceramics made by examples 1-6 curing TRPO simulated waste at different sintering temperatures, where x is the mass percent of TRPO simulated waste;

FIG. 5 is a graph of hardness test results of gadolinium zirconate ceramics made by comparative example and gadolinium zirconate ceramics made by examples 1-6 solidifying TRPO simulation waste, wherein (a) is a graph of hardness versus temperature of gadolinium zirconate ceramics and gadolinium zirconate ceramics solidifying TRPO simulation waste, and (b) is a graph of hardness versus solid solution amount of gadolinium zirconate ceramics and gadolinium zirconate ceramics solidifying TRPO simulation waste, wherein x is mass percent of TRPO simulation waste.

Detailed Description

The technical solutions of the present invention will be described in detail and fully with reference to the accompanying drawings, which are used for describing the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The simulation of TRPO mimic waste in the following examples is An-containing alpha waste after TRPO separation in table 1, the elements and parts by weight of the An-containing alpha mimic waste obtained are shown in table 2:

table 2 elements and parts by weight in An-containing alpha-model waste

The raw materials of the alpha simulation waste containing An are metal nitrate and molybdenum oxide (MoO) corresponding to elements except Mo, Ru and Pd in Table 2₃) Ruthenium oxide (RuO)₂) Oxygen, oxygenPalladium oxide (PdO), the oxide of which is not soluble in nitric acid, is used as it is as a raw material.

The raw materials used in the invention are as follows: the solid raw material used in the experiment is gadolinium nitrate hexahydrate (molecular formula Gd (NO)₃)₃·6H₂O), provided by Rake rare earth chemical reagent liability company Limited, with a purity of 99.99%; zirconium nitrate pentahydrate (Zr (NO)₃)₄·5H₂O) is provided by an avastin reagent, and the purity is 99.99 percent; yttrium nitrate hexahydrate (Y (NO)₃)₃·6H₂O), praseodymium nitrate hexahydrate (Pr (NO)₃)₃·6H₂O), neodymium nitrate hexahydrate (Nd (NO)₃)₃·6H₂O), samarium nitrate hexahydrate (Sm (NO)₃)₃·6H₂O), europium nitrate hexahydrate (Eu (NO)₃)₃·6H₂O), lanthanum nitrate hexahydrate (La (NO)₃)₃·6H₂O), cerium nitrate hexahydrate (Ce (NO)₃)₃·6H₂O), molybdenum oxide (MoO)₃) Purity of 99.99%, ruthenium oxide (RuO)₂·nH₂O, content: ru is more than or equal to 59.5%), palladium oxide (PdO, content: pb is more than or equal to 86.0 percent) and is provided by the Yutai Qixin chemical company Limited; absolute ethyl alcohol (CH)₃CH₂OH) was supplied by Chengdu chemical reagent Co., Ltd, and the purity was 99.7%.

The above nitrates were prepared into solutions with the concentrations respectively: y is 42.38g/L, La is 52.4g/L, Ce is 67.95g/L, Pr is 50.45g/L, Nd is 62.88g/L, Eu is 66.1g/L, Gd is 93.8g/L, Sm is 63.22g/L, and Zr is 43.1 g/L.

The equipment used in the invention: precision electronic balances are available from Shenyang Longteng electronics, Inc.; the electric heating constant temperature blast drying oven is manufactured by Shanghai Jing Macro experimental facilities, Inc.; mortar and screens were supplied by metropolis Chang certified glass ltd; the hydrothermal reaction kettle is provided by the laboratory equipment Limited company of the Sean apparatus; muffle furnaces are available from Bessel Equipment technology, Inc., Anhui; graphite molds are provided by meilson advanced graphite (kunshan) ltd; the bench powder dry press is provided by Tianjin Corp Gaoxin Co., Ltd; the microwave sintering furnace is provided by sanden thermal technology limited in Hunan province.

Comparative example

This comparative example is a gadolinium zirconate ceramic for the preparation of solidified 0 wt% TRPO simulated waste comprising the steps of:

(1) preparation of precursor powder

Preparation of 25g of precursor powder containing Gd₂Zr₂O₇100 wt% of the TRPO simulation waste, and 0 wt% of the TRPO simulation waste, Gd₂Zr₂O₇Has a mass of 25 g. Gd is obtained by calculation₂Zr₂O₇Gd12.91g and Zr 7.49g are needed; gd is calculated according to the concentration of the corresponding element in the prepared nitrate solution₂Zr₂O₇Taking Gd (NO) as a medium demand₃)₃·6H₂O solution 137.64mL, Zr (NO)₃)₄·5H₂The O solution was 173.775 mL.

Measured amount of Gd (NO)₃)₃·6H₂O solution and Zr (NO)₃)₄·5H₂The O solution was placed in a beaker having a capacity of 3L, and 36.76g of citric acid was weighed and added to 500mL of deionized water. Heating the mixed solution to 250 ℃ for presintering for 5 hours, and decomposing carbon elements and nitrogen elements in the mixed solution in a gas form to obtain fluffy and dry primary powder (xerogel); grinding the primary powder in an agate mortar, then placing the powder at 900 ℃ for heat treatment for 4 hours to fully burn chlorine and nitrogen in the powder, removing impurity particles in the powder, then placing the powder in a ball milling pot to perform ball milling for 20 hours by taking absolute ethyl alcohol as a medium, and fully mixing the sample to obtain a precursor with good dispersibility and small particles; and (3) drying the precursor in an electrothermal constant-temperature blast drying oven at 70 ℃, after full drying, continuously calcining at 900 ℃ for 4 hours, grinding the precursor, and sieving by a 200-mesh sieve to obtain precursor powder.

(2) Preparation of a biscuit

And (2) adopting common dry pressing for forming, weighing 0.85g of precursor powder prepared in the step (1) by using an analytical balance, loading the precursor powder into a powder tablet press, applying axial pressure to the powder, maintaining the pressure for 3min under the condition of 6MPa, pressing into a wafer with the diameter of 12mm, then carrying out vacuum packaging by using a plastic packaging bag, putting into hydraulic oil of a cold isostatic press, slowly applying pressure until the pressure reaches 250MPa, maintaining the pressure for 15min, and reducing the pressure to obtain a biscuit.

(3) Preparation of cured body ceramics

Dividing the biscuit prepared in the step (2) into four groups, respectively heating the biscuit groups to 1100 ℃, 1200 ℃, 1300 ℃ and 1400 ℃ by adopting a microwave sintering method according to a temperature control program given in a table 3, sintering, preserving heat for 30 minutes at the temperature, and then cooling to room temperature to obtain the gadolinium zirconate ceramic sintered at the four temperatures.

TABLE 3 microwave sintering temperature control procedure

Note: 1. the temperature control program starts the temperature rise timing from 250 ℃.

2. The temperature control flow is described with the sintering temperature of 1100 ℃, the temperature rise time from 250 ℃→ 500 → 700 → 900 → 1100 ℃ is 35min, 25min, and 25min in this order, then the temperature is maintained at 1100 ℃ for 30min, then the temperature decrease time from 1100 ℃→ 900 → 700 → 500 ℃ is 40min, 20min, and 40min in this order, and finally the temperature is naturally cooled to room temperature below 500 ℃.

Example 1

This example is a gadolinium zirconate ceramic for the preparation of solidified 10 wt% TRPO simulated waste comprising the steps of:

(1) preparation of precursor powder

Preparation of 25g of precursor powder containing Gd₂Zr₂O₇90 wt% of the TRPO simulation waste and 10 wt% of the TRPO simulation waste, Gd₂Zr₂O₇Has a mass of 22.5g and a mass of TRPO mimic waste of 2.5 g. Gd is obtained by calculation₂Zr₂O₇The amount of Gd required in the reaction solution is 11.475g, and the amount of Zr required in the reaction solution is 6.658 g; the TRPO simulated waste calculated according to Table 2 required Y of 0.095g, La of 0.248g, Ce of 0.477g, Pr of 0.2343g, Nd of 0.8123g, and Eu of 0.03gGd was 0.0373g, Sm was 0.1475g, Mo was 0.291g, Ru was 0.0567g, and Pd was 0.0743 g. Among them, molybdenum, ruthenium and palladium are used as corresponding oxides because they have no nitrate. Calculating Gd according to the concentration of the corresponding elements in the prepared nitrate solution and the weight of Mo, Ru and Pd₂Zr₂O₇Taking Gd (NO) as a medium demand₃)₃·6H₂O solution 123.85mL, Zr (NO)₃)₄·5H₂The O solution is 156.38 mL; respectively measuring Y (NO) from TRPO simulation waste₃)₃·6H₂O solution 2.24mL, La (NO)₃)₃·6H₂O solution 4.73mL, Ce (NO)₃)₃·6H₂O solution 7.02mL, Pr (NO)₃)₃·6H₂O solution 4.65mL, Nd (NO)₃)₃·6H₂O solution 12.92mL, Eu (NO)₃)₃·6H₂O solution 0.45mL, Gd (NO)₃)₃·6H₂0.4mL of Sm (NO) in O solution₃)₃·6H₂2.34mL of O solution, MoO₃0.388g, RuO₂·nH₂O is 0.100g, PdO is 0.126 g.

Measured amount of Gd (NO)₃)₃·6H₂O solution, Zr (NO)₃)₄·5H₂O solution, Y (NO)₃)₃·6H₂O solution, La (NO)₃)₃·6H₂O solution, Ce (NO)₃)₃·6H₂O solution, Pr (NO)₃)₃·6H₂O solution, Nd (NO)₃)₃·6H₂O、Eu(NO₃)₃·6H₂O solution, Sm (NO)₃)₃·6H₂O solution and the like are put into a beaker with the capacity of 3L, 36.76g of citric acid is weighed, and deionized water is added to 500 mL. Heating the mixed solution to 250 ℃ for presintering for 5 hours to obtain fluffy and dry primary powder (xerogel) by decomposing carbon elements and nitrogen elements in the mixed solution in a gas form; grinding the primary powder in an agate mortar tank, and then placing the powder at 900 ℃ for heat treatment for 4 hours to fully burn chlorine elements and nitrogen elements in the powder and remove impurity particles in the powder; then weighing the MoO₃、RuO₂·nH₂O, PdO, adding the powder into the primary powder, putting the powder into a ball milling tank, and ball milling the powder for 20 hours by taking absolute ethyl alcohol as a medium, and fully mixing the sample to obtain a precursor with good dispersibility and small particles; and (3) drying the precursor in an electrothermal constant-temperature blast drying oven at 70 ℃, after full drying, continuously calcining at 900 ℃ for 4 hours, grinding the precursor, and sieving by a 200-mesh sieve to obtain precursor powder.

(2) Preparation of a biscuit

(3) Preparation of cured body ceramics

Dividing the biscuit prepared in the step (2) into four groups, respectively heating the biscuit groups to 1100 ℃, 1200 ℃, 1300 ℃ and 1400 ℃ by adopting a microwave sintering method according to a temperature control program given in a table 3, sintering, preserving heat for 30 minutes at the temperature, and then cooling to room temperature to obtain the gadolinium zirconate ceramics for solidifying TRPO simulation waste sintered at the four temperatures.

Example 2

This example is a gadolinium zirconate ceramic for making solidified 20 wt% TRPO simulated waste comprising the steps of:

(1) preparation of precursor powder

Preparation of 25g of precursor powder containing Gd₂Zr₂O₇80 wt% of the TRPO simulation waste and 20 wt% of the TRPO simulation waste, Gd₂Zr₂O₇Has a mass of 20g and a mass of 5g of TRPO simulated waste. Gd is obtained by calculation₂Zr₂O₇The Gd is required to be 10.328g, and the Zr is required to be 5.992 g; the TRPO simulated waste calculated according to Table 2 required Y of 0.19g, La of 0.495g, Ce of 0.954g, Pr of 0.4685g, Nd of 1.6245g, Eu of 0.06g0.0745g of Gd, 0.295g of Sm, 0.582g of Mo, 0.1135g of Ru and 0.1485g of Pd. Among them, molybdenum, ruthenium and palladium are used as corresponding oxides because they have no nitrate. Calculating Gd according to the concentration of the corresponding elements in the prepared nitrate solution and the weight of Mo, Ru and Pd₂Zr₂O₇Taking Gd (NO) as a medium demand₃)₃·6H₂O solution 110.11mL, Zr (NO)₃)₄·5H₂The O solution is 139.02 mL; respectively measuring Y (NO) from TRPO simulation waste₃)₃·6H₂O solution 4.48mL, La (NO)₃)₃·6H₂O solution 9.45mL, Ce (NO)₃)₃·6H₂O solution 14.04mL, Pr (NO)₃)₃·6H₂O solution 9.29mL, Nd (NO)₃)₃·6H₂O solution 25.83mL, Eu (NO)₃)₃·6H₂O solution 0.9mL, Gd (NO)₃)₃·6H₂0.8mL of Sm (NO) in O solution₃)₃·6H₂4.67mL of O solution, MoO₂0.776g, RuO₂·nH₂O was 0.199g, PdO was 0.251 g.

Measured amount of Gd (NO)₃)₃·6H₂O solution, Zr (NO)₃)₄·5H₂O solution, Y (NO)₃)₃·6H₂O solution, La (NO)₃)₃·6H₂O solution, Ce (NO)₃)₃·6H₂O solution, Pr (NO)₃)₃·6H₂O solution, Nd (NO)₃)₃·6H₂O solution, Eu (NO)₃)₃·6H₂O solution, Sm (NO)₃)₃·6H₂O solution and the like are put into a beaker with the capacity of 3L, 36.76g of citric acid is weighed, and deionized water is added to 500 mL. Heating the mixed solution to 250 ℃ for presintering for 5 hours to obtain fluffy and dry primary powder (xerogel) by decomposing carbon elements and nitrogen elements in the mixed solution in a gas form; grinding the primary powder in an agate mortar tank, and then placing the powder at 900 ℃ for heat treatment for 4 hours to fully burn chlorine elements and nitrogen elements in the powder and remove impurity particles in the powder; then weighing the MoO₃、RuO₂·nH₂O, PdO, adding the powder into the primary powder, putting the powder into a ball milling tank, and ball milling the powder for 20 hours by taking absolute ethyl alcohol as a medium, and fully mixing the sample to obtain a precursor with good dispersibility and small particles; and (3) drying the precursor in an electrothermal constant-temperature blast drying oven at 70 ℃, after full drying, continuously calcining at 900 ℃ for 4 hours, grinding the precursor, and sieving by a 200-mesh sieve to obtain precursor powder.

(2) Preparation of a biscuit

(3) Preparation of cured body ceramics

Example 3

This example is a gadolinium zirconate ceramic for making solidified 30 wt% TRPO simulated waste comprising the steps of:

(1) preparation of precursor powder

Preparation of 25g of precursor powder containing Gd₂Zr₂O₇70 wt% of the TRPO simulated waste and 30 wt% of the TRPO simulated waste, Gd₂Zr₂O₇Has a mass of 17.5g and a mass of TRPO mimic waste of 7.5 g. Gd is obtained by calculation₂Zr₂O₇The Gd is required to be 9.037g, and the Zr is required to be 5.243 g; the TRPO simulated waste calculated according to Table 2 required Y of 0.285g, La of 0.745g, Ce of 1.431g, Pr of 0.7028g, Nd of 2.4368g, Eu of0.09g, 0.1118g of Gd, 0.4425g of Sm, 0.783g of Mo, 0.1703g of Ru and 0.2228g of Pd. Among them, molybdenum, ruthenium and palladium are used as corresponding oxides because they have no nitrate. Calculating Gd according to the concentration of the corresponding elements in the prepared nitrate solution and the weight of Mo, Ru and Pd₂Zr₂O₇Taking Gd (NO) as a medium demand₃)₃·6H₂O solution 96.35mL, Zr (NO)₃)₄·5H₂The O solution is 121.64 mL; respectively measuring Y (NO) from TRPO simulation waste₃)₃·6H₂O solution 6.72mL, La (NO)₃)₃·6H₂O solution 14.18mL, Ce (NO)₃)₃·6H₂O solution 21.06mL, Pr (NO)₃)₃·6H₂O solution 13.94mL, Nd (NO)₃)₃·6H₂O solution 38.75mL, Eu (NO)₃)₃·6H₂O solution 1.35mL, Gd (NO)₃)₃·6H₂1.2mL of Sm (NO) in O solution₃)₃·6H₂The O solution is 7.01mL, MoO₃1.164g, RuO₂·nH₂O is 0.288g, PdO is 0.377 g.

Measured amount of Gd (NO)₃)₃·6H₂O solution, Zr (NO)₃)₄·5H₂O solution, Y (NO)₃)₃·6H₂O solution, La (NO)₃)₃·6H₂O solution, Ce (NO)₃)₃·6H₂O solution, Pr (NO)₃)₃·6H₂O solution, Nd (NO)₃)₃·6H₂O solution, Eu (NO)₃)₃·6H₂O solution, Sm (NO)₃)₃·6H₂O solution and the like are put into a beaker with the capacity of 3L, 36.76g of citric acid is weighed, and deionized water is added to 500 mL. Heating the mixed solution to 250 ℃ for presintering for 5 hours to obtain fluffy and dry primary powder (xerogel) by decomposing carbon elements and nitrogen elements in the mixed solution in a gas form; grinding the primary powder in an agate mortar tank, and then placing the powder at 900 ℃ for heat treatment for 4 hours to fully burn chlorine elements and nitrogen elements in the powder and remove impurity particles in the powder; then weighingMoO₂、RuO₂·nH₂O, PdO, adding the powder into the primary powder, putting the powder into a ball milling tank, and ball milling the powder for 20 hours by taking absolute ethyl alcohol as a medium, and fully mixing the sample to obtain a precursor with good dispersibility and small particles; and (3) drying the precursor in an electrothermal constant-temperature blast drying oven at 70 ℃, after full drying, continuously calcining at 900 ℃ for 4 hours, grinding the precursor, and sieving by a 200-mesh sieve to obtain precursor powder.

(2) Preparation of a biscuit

(3) Preparation of cured body ceramics

Example 4

This example is a gadolinium zirconate ceramic for making solidified 40 wt% TRPO simulated waste comprising the steps of:

(1) preparation of precursor powder

Preparation of 25g of precursor powder containing Gd₂Zr₂O₇60 wt% of the TRPO simulated waste and 40 wt% of the TRPO simulated waste, Gd₂Zr₂O₇Has a mass of 15g and a mass of 10g of TRPO simulated waste. Gd is obtained by calculation₂Zr₂O₇The Gd is required to be 7.746g, and the Zr is required to be 4.494 g; the TRPO simulated waste calculated according to Table 2 required Y of 0.38g, La of 0.99g, Ce of 1.908g, Pr of 0.937g, Nd of 3.249g, Eu0.12g of Gd, 0.149g of Sm, 0.59g of Sm, 1.164g of Mo, 0.227g of Ru and 0.297g of Pd. Among them, molybdenum, ruthenium and palladium are used as corresponding oxides because they have no nitrate. Calculating Gd according to the concentration of the corresponding elements in the prepared nitrate solution and the weight of Mo, Ru and Pd₂Zr₂O₇Taking Gd (NO) as a medium demand₃)₃·6H₂O solution 82.5825mL, Zr (NO)₃)₄·5H₂The O solution is 104.265 mL; respectively measuring Y (NO) from TRPO simulation waste₃)₃·6H₂O solution 8.96mL, La (NO)₃)₃·6H₂O solution 18.90mL, Ce (NO)₃)₃·6H₂O solution 28.08mL, Pr (NO)₃)₃·6H₂O solution 18.58mL, Nd (NO)₃)₃·6H₂O solution 51.66mL, Eu (NO)₃)₃·6H₂O solution 1.8mL, Gd (NO)₃)₃·6H₂1.6mL of Sm (NO) in O solution₃)₃·6H₂The O solution was 9.34mL, MoO₂1.552g, RuO₂·nH₂O is 0.398g, PdO is 0.502 g.

Measured amount of Gd (NO)₃)₃·6H₂O solution, Zr (NO)₃)₄·5H₂O solution, Y (NO)₃)₃·6H₂O solution, La (NO)₃)₃·6H₂O solution, Ce (NO)₃)₃·6H₂O solution, Pr (NO)₃)₃·6H₂O solution, Nd (NO)₃)₃·6H₂O solution, Eu (NO)₃)₃·6H₂O solution, Sm (NO)₃)₃·6H₂O solution and the like are put into a beaker with the capacity of 3L, 36.76g of citric acid is weighed, and deionized water is added to 500 mL. Heating the mixed solution to 250 ℃ for presintering for 5 hours to obtain fluffy and dry primary powder (xerogel) by decomposing carbon elements and nitrogen elements in the mixed solution in a gas form; grinding the primary powder in an agate mortar tank, and then placing the powder at 900 ℃ for heat treatment for 4 hours to fully burn chlorine elements and nitrogen elements in the powder and remove impurity particles in the powder; then weighingMoO₃、RuO₂·nH₂O, PdO, adding the powder into the primary powder, putting the powder into a ball milling tank, and ball milling the powder for 20 hours by taking absolute ethyl alcohol as a medium, and fully mixing the sample to obtain a precursor with good dispersibility and small particles; and (3) drying the precursor in an electrothermal constant-temperature blast drying oven at 70 ℃, after full drying, continuously calcining at 900 ℃ for 4 hours, grinding the precursor, and sieving by a 200-mesh sieve to obtain precursor powder.

(2) Preparation of a biscuit

(3) Preparation of cured body ceramics

Example 5

This example is a gadolinium zirconate ceramic for the preparation of 50 wt% TRPO simulated waste cured comprising the steps of:

(1) preparation of precursor powder

Preparation of 25g of precursor powder containing Gd₂Zr₂O₇50 wt% of the TRPO simulation waste, and 50 wt% of the Gd₂Zr₂O₇Has a mass of 12.5g and a mass of TRPO mimic waste of 12.5 g. Gd is obtained by calculation₂Zr₂O₇The Gd is required to be 6.4566g, and the Zr is required to be 3.7457 g; the TRPO simulated waste calculated according to Table 2 required Y of 0.475g, La of 1.2375g, Ce of 2.475g, Pr of 1.1713g, and Nd of 40613g, Eu 0.15g, Gd 0.1863g, Sm 0.7375g, Mo 1.455g, Ru 0.2838g, Pd 0.3715 g. Among them, molybdenum, ruthenium and palladium are used as corresponding oxides because they have no nitrate. Calculating Gd according to the concentration of the corresponding elements in the prepared nitrate solution and the weight of Mo, Ru and Pd₂Zr₂O₇Taking Gd (NO) as a medium demand₃)₃·6H₂O solution 68.84mL, Zr (NO)₃)₄·5H₂The O solution is 86.90 mL; respectively measuring Y (NO) from TRPO simulation waste₃)₃·6H₂O solution 11.2mL, La (NO)₃)₃·6H₂O solution 23.61mL, Ce (NO)₃)₃·6H₂O solution 36.42mL, Pr (NO)₃)₃·6H₂23.22mL of O solution in Nd (NO)₃)₃·6H₂O solution 64.59mL, Eu (NO)₃)₃·6H₂O solution 2.27mL, Gd (NO)₃)₃·6H₂1.99mL of Sm (NO) in O solution₃)₃·6H₂The O solution was 11.66mL, MoO₃1.940g, RuO₂·nH₂O is 0.497g, PdO is 0.628 g.

Measured amount of Gd (NO)₃)₃·6H₂O solution, Zr (NO)₃)₄·5H₂O solution, Y (NO)₃)₃·6H₂O solution, La (NO)₃)₃·6H₂O solution, Ce (NO)₃)₃·6H₂O solution, Pr (NO)₃)₃·6H₂O solution, Nd (NO)₃)₃·6H₂O solution, Eu (NO)₃)₃·6H₂O solution, Sm (NO)₃)₃·6H₂O solution and the like are put into a beaker with the capacity of 3L, 36.76g of citric acid is weighed, and deionized water is added to 500 mL. Heating the mixed solution to 250 ℃ for presintering for 5 hours to obtain fluffy and dry primary powder (xerogel) by decomposing carbon elements and nitrogen elements in the mixed solution in a gas form; grinding the primary powder in an agate mortar tank, and then placing the powder at 900 ℃ for heat treatment for 4 hours to fully burn chlorine elements and nitrogen elements in the powder and remove impurity particles in the powder;then weighing the MoO₂、RuO₂·nH₂O, PdO, adding the powder into the primary powder, putting the powder into a ball milling tank, and ball milling the powder for 20 hours by taking absolute ethyl alcohol as a medium, and fully mixing the sample to obtain a precursor with good dispersibility and small particles; and (3) drying the precursor in an electrothermal constant-temperature blast drying oven at 70 ℃, after full drying, continuously calcining at 900 ℃ for 4 hours, grinding the precursor, and sieving by a 200-mesh sieve to obtain precursor powder.

(2) Preparation of a biscuit

(3) Preparation of cured body ceramics

Example 6

This example is a gadolinium zirconate ceramic for making 60 wt% TRPO waste cured comprising the steps of:

(1) preparation of precursor powder

Preparation of 25g of precursor powder containing Gd₂Zr₂O₇40 wt% of the TRPO simulation waste and 60 wt% of the TRPO simulation waste, Gd₂Zr₂O₇Has a mass of 10g and a mass of 15g of TRPO simulated waste. Gd is obtained by calculation₂Zr₂O₇The Gd is required to be 5.164g, and the Zr is required to be 2.996 g; the TRPO simulated waste calculated according to Table 2 required Y of 0.57g, La of 1.485g, Ce of 2.862g, Pr of 1.4055g, and Nd of4.8735g, Eu 0.18g, Gd 0.2235g, Sm 0.885g, Mo 1.746g, Ru 0.341g, Pd 0.446 g. Among them, molybdenum, ruthenium and palladium are used as corresponding oxides because they have no nitrate. Calculating Gd according to the concentration of the corresponding elements in the prepared nitrate solution and the weight of Mo, Ru and Pd₂Zr₂O₇Taking Gd (NO) as a medium demand₃)₃·6H₂O solution 55.05mL, Zr (NO)₃)₄·5H₂The O solution is 69.51 mL; respectively measuring Y (NO) from TRPO simulation waste₃)₃·6H₂O solution 13.44mL, La (NO)₃)₃·6H₂O solution 28.34mL, Ce (NO)₃)₃·6H₂O solution 42.12mL, Pr (NO)₃)₃·6H₂O solution 27.85mL, Nd (NO)₃)₃·6H₂O solution 77.50mL, Eu (NO)₃)₃·6H₂O solution 2.72mL, Gd (NO)₃)₃·6H₂2.38mL of Sm (NO) in O solution₃)₃·6H₂The O solution is 14.00mL, MoO₃2.328g, RuO₂·nH₂O is 0.596g, PdO is 0.754 g.

Measured amount of Gd (NO)₃)₃·6H₂O solution, Zr (NO)₃)₄·5H₂O solution, Y (NO)₃)₃·6H₂O solution, La (NO)₃)₃·6H₂O solution, Ce (NO)₃)₃·6H₂O solution, Pr (NO)₃)₃·6H₂O solution, Nd (NO)₃)₃·6H₂O solution, Eu (NO)₃)₃·6H₂O solution, Sm (NO)₃)₃·6H₂O solution and the like are put into a beaker with the capacity of 3L, 36.76g of citric acid is weighed, and deionized water is added to 500 mL. Heating the mixed solution to 250 ℃ for presintering for 5 hours to obtain fluffy and dry primary powder (xerogel) by decomposing carbon elements and nitrogen elements in the mixed solution in a gas form; grinding the primary powder in an agate mortar tank, and then placing the powder at 900 ℃ for heat treatment for 4 hours to fully burn chlorine elements and nitrogen elements in the powder and remove impurity particles in the powder; then, the product is processedWeighing MoO₂、RuO₂·nH₂O, PdO, adding the powder into the primary powder, putting the powder into a ball milling tank, and ball milling the powder for 20 hours by taking absolute ethyl alcohol as a medium, and fully mixing the sample to obtain a precursor with good dispersibility and small particles; and (3) drying the precursor in an electrothermal constant-temperature blast drying oven at 70 ℃, after full drying, continuously calcining at 900 ℃ for 4 hours, grinding the precursor, and sieving by a 200-mesh sieve to obtain precursor powder.

(2) Preparation of a biscuit

(3) Preparation of cured body ceramics

Example 7

(1) preparation of precursor powder

Preparation of 25g of precursor powder containing Gd₂Zr₂O₇50 wt% of the TRPO simulation waste, and 50 wt% of the Gd₂Zr₂O₇Has a mass of 12.5g and a mass of TRPO mimic waste of 12.5 g. Gd is obtained by calculation₂Zr₂O₇The Gd is required to be 6.4566g, and the Zr is required to be 3.7457 g; the TRPO simulated waste calculated according to Table 2 required Y of 0.475g, La of 1.2375g, Ce of 2.475g and Pr of 1.17 g13g, 4.0613g for Nd, 0.15g for Eu, 0.1863g for Gd, 0.7375g for Sm, 1.455g for Mo, 0.2838g for Ru and 0.3715g for Pd. Among them, molybdenum, ruthenium and palladium are used as corresponding oxides because they have no nitrate. Calculating Gd according to the concentration of the corresponding elements in the prepared nitrate solution and the weight of Mo, Ru and Pd₂Zr₂O₇Taking Gd (NO) as a medium demand₃)₃·6H₂O solution 68.84mL, Zr (NO)₃)₄·5H₂The O solution is 86.90 mL; respectively measuring Y (NO) from TRPO simulation waste₃)₃·6H₂O solution 11.2mL, La (NO)₃)₃·6H₂O solution 23.61mL, Ce (NO)₃)₃·6H₂O solution 36.42mL, Pr (NO)₃)₃·6H₂23.22mL of O solution in Nd (NO)₃)₃·6H₂O solution 64.59mL, Eu (NO)₃)₃·6H₂O solution 2.27mL, Gd (NO)₃)₃·6H₂1.99mL of Sm (NO) in O solution₃)₃·6H₂The O solution was 11.66mL, MoO₃1.940g, RuO₂·nH₂O is 0.497g, PdO is 0.628 g.

Measured amount of Gd (NO)₃)₃·6H₂O solution, Zr (NO)₃)₄·5H₂O solution, Y (NO)₃)₃·6H₂O solution, La (NO)₃)₃·6H₂O solution, Ce (NO)₃)₃·6H₂O solution, Pr (NO)₃)₃·6H₂O solution, Nd (NO)₃)₃·6H₂O solution, Eu (NO)₃)₃·6H₂O solution, Sm (NO)₃)₃·6H₂O solution and the like are put into a beaker with the capacity of 3L, 36.76g of citric acid is weighed, and deionized water is added to 500 mL. Heating the mixed solution to 300 ℃ for presintering for 4 hours to obtain fluffy and dry primary powder (xerogel) by decomposing carbon elements and nitrogen elements in the mixed solution in a gas form; grinding the primary powder in an agate mortar, and heat-treating at 800 deg.C for 3 hr to fully burn chlorine and nitrogen and remove impuritiesA proton particle; then weighing the MoO₃、RuO₂·nH₂O, PdO, adding the powder into the primary powder, putting the powder into a ball milling tank, and ball milling the powder for 24 hours by taking absolute ethyl alcohol as a medium, and fully mixing the sample to obtain a precursor with good dispersibility and small particles; and (3) drying the precursor in an electrothermal constant-temperature blast drying oven at 70 ℃, after full drying, continuously calcining at 800 ℃ for 5 hours, grinding the precursor, and sieving by a 200-mesh sieve to obtain precursor powder.

(2) Preparation of a biscuit

And (2) adopting common dry pressing for forming, weighing 0.85g of precursor powder prepared in the step (1) by using an analytical balance, loading the precursor powder into a powder tablet press, applying axial pressure to the powder, maintaining the pressure for 3min under the condition of 8MPa, pressing into a wafer with the diameter of 12mm, then carrying out vacuum packaging by using a plastic packaging bag, putting into hydraulic oil of a cold isostatic press, slowly applying pressure until the pressure reaches 250MPa, maintaining the pressure for 20min, and reducing the pressure to obtain a biscuit.

(3) Preparation of cured body ceramics

Dividing the biscuit prepared in the step (2) into four groups, respectively heating the biscuit groups to 1100 ℃, 1200 ℃, 1300 ℃ and 1400 ℃ by adopting a microwave sintering method according to a temperature control program given in a table 3, sintering, preserving heat for 40 minutes at the temperature, and then cooling to room temperature to obtain the gadolinium zirconate ceramics for solidifying TRPO simulation waste sintered at the four temperatures.

Example 8

(1) preparation of precursor powder

Preparation of 25g of precursor powder containing Gd₂Zr₂O₇40 wt% of the TRPO simulation waste and 60 wt% of the TRPO simulation waste, Gd₂Zr₂O₇Has a mass of 10g and a mass of 15g of TRPO simulated waste. Gd is obtained by calculation₂Zr₂O₇The Gd is required to be 5.164g, and the Zr is required to be 2.996 g; the TRPO simulated waste is calculated according to the table 2 to obtain the required Y of 0.57g, La of 1.485g, Ce of 2.862g and Pr of 1.4055g, Nd 4.8735g, Eu 0.18g, Gd 0.2235g, Sm 0.885g, Mo 1.746g, Ru 0.341g, Pd 0.446 g. Among them, molybdenum, ruthenium and palladium are used as corresponding oxides because they have no nitrate. Calculating Gd according to the concentration of the corresponding elements in the prepared nitrate solution and the weight of Mo, Ru and Pd₂Zr₂O₇Taking Gd (NO) as a medium demand₃)₃·6H₂O solution 55.05mL, Zr (NO)₃)₄·5H₂The O solution is 69.51 mL; respectively measuring Y (NO) from TRPO simulation waste₃)₃·6H₂O solution 13.44mL, La (NO)₃)₃·6H₂O solution 28.34mL, Ce (NO)₃)₃·6H₂O solution 42.12mL, Pr (NO)₃)₃·6H₂O solution 27.85mL, Nd (NO)₃)₃·6H₂O solution 77.50mL, Eu (NO)₃)₃·6H₂O solution 2.72mL, Gd (NO)₃)₃·6H₂2.38mL of Sm (NO) in O solution₃)₃·6H₂The O solution is 14.00mL, MoO₃2.328g, RuO₂·nH₂O is 0.596g, PdO is 0.754 g.

Measured amount of Gd (NO)₃)₃·6H₂O solution, Zr (NO)₃)₄·5H₂O solution, Y (NO)₃)₃·6H₂O solution, La (NO)₃)₃·6H₂O solution, Ce (NO)₃)₃·6H₂O solution, Pr (NO)₃)₃·6H₂O solution, Nd (NO)₃)₃·6H₂O solution, Eu (NO)₃)₃·6H₂O solution, Sm (NO)₃)₃·6H₂O solution and the like are put into a beaker with the capacity of 3L, 36.76g of citric acid is weighed, and deionized water is added to 500 mL. Heating the mixed solution to 250 ℃ for presintering for 6 hours to obtain fluffy and dry primary powder (xerogel) by decomposing carbon elements and nitrogen elements in the mixed solution in a gas form; grinding the primary powder in an agate mortar, and heat-treating at 1000 deg.C for 4 hr to fully burn chlorine and nitrogen and remove impuritiesA proton particle; then weighing the MoO₂、RuO₂·nH₂O, PdO, adding the powder into the primary powder, putting the powder into a ball milling tank, and ball milling the powder for 24 hours by taking absolute ethyl alcohol as a medium, and fully mixing the sample to obtain a precursor with good dispersibility and small particles; and (3) drying the precursor in an electrothermal constant-temperature blast drying oven at 70 ℃, after full drying, continuously calcining at 1000 ℃ for 6 hours, grinding the precursor, and sieving by a 200-mesh sieve to obtain precursor powder.

(2) Preparation of a biscuit

And (2) adopting common dry pressing for forming, weighing 0.85g of precursor powder prepared in the step (1) by using an analytical balance, loading the precursor powder into a powder tablet press, applying axial pressure to the powder, maintaining the pressure for 5min under the condition of 7MPa, pressing into a wafer with the diameter of 12mm, then carrying out vacuum packaging by using a plastic packaging bag, putting into hydraulic oil of a cold isostatic press, slowly applying pressure until the pressure reaches 250MPa, maintaining the pressure for 20min, and reducing the pressure to obtain a biscuit.

(3) Preparation of cured body ceramics

Dividing the biscuit prepared in the step (2) into four groups, respectively heating the biscuit groups to 1100 ℃, 1200 ℃, 1300 ℃ and 1400 ℃ by adopting a microwave sintering method according to a temperature control program given in a table 3, sintering, preserving heat for 20 minutes at the temperature, and then cooling to room temperature to obtain the gadolinium zirconate ceramics for solidifying TRPO simulation waste sintered at the four temperatures.

The morphology and properties of gadolinium zirconate ceramics prepared in comparative examples and precursor powders prepared in examples 1-6, solidified TRPO simulation waste, were analyzed as follows.

1. Precursor powder

The primary powder (before ball milling) and the precursor (after ball milling) obtained in the step (1) of example 5 are subjected to morphology analysis by a scanning electron microscope, and SEM images of the primary powder and the precursor are shown in fig. 1, and it can be seen from fig. 1 that the precursor powder has a uniform structure and good dispersibility, and no large aggregates exist.

XRD tests were performed on the precursor powders prepared in the comparative example and examples 1 to 6, and the test results are shown in FIG. 2, and it can be seen from FIG. 2 that the precursor powder maintained the same single fluorite structure as the comparative example when TRPO simulation waste was 10 to 60 wt%.

2. Gadolinium zirconate ceramic for solidifying large-capacity TRPO simulation waste

(1) Morphology of

The sections of four kinds of gadolinium zirconate ceramics with different sintering temperatures prepared in a comparative example and four kinds of gadolinium zirconate ceramics with different sintering temperatures for solidifying TRPO simulation waste prepared in examples 1 to 6 respectively are analyzed by a scanning electron microscope, the SEM images of the sections are shown in figure 3, and as can be seen from figure 3, the gadolinium zirconate ceramics with a fine structure for solidifying TRPO simulation waste with uniform particle size distribution can be prepared by a microwave sintering method, and the crystal grains are gradually increased along with the increase of the solid solution amount of the TRPO simulation waste at the same sintering temperature; when the solid solution amount of TRPO simulation waste is the same, along with the increase of sintering temperature, crystal grains grow gradually and gaps in the ceramic are reduced gradually, so that the densification of the solidified ceramic is facilitated, and actinides are not easy to leach out of a solidified body. In addition, when the sintering temperature is lower than 1400 ℃, the grain size of the gadolinium zirconate solid solution ceramic is about 40-100 nanometers, and when the sintering temperature is 1400 ℃, the gadolinium zirconate solid solution ceramic is obviously densified, grain boundaries are connected, and the grain size is about submicron.

(2) Density of

The gadolinium zirconate ceramics of four different sintering temperatures prepared in the comparative example and the gadolinium zirconate ceramics of solidified TRPO simulation waste of four different sintering temperatures respectively prepared in examples 1 to 6 were subjected to density detection (using a density balance based on archimedes' principle), and the detected densities were compared with the theoretical densities corresponding thereto to obtain the relative densities of the gadolinium zirconate ceramics of different sintering temperatures, as shown in fig. 4. Fig. 4 shows that the density gradually increases with the increase of sintering temperature under the same solid solution amount of TRPO-mimetic waste.

From the analysis, the Gd of the high-density fine-grain solidified TRPO simulated waste can be prepared while realizing large-capacity solidification of the TRPO simulated waste by the method provided by the invention₂Zr₂O₇A ceramic solidified body.

(3) Hardness of

The gadolinium zirconate ceramics prepared in the comparative example and cured TRPO simulation waste in the three different sintering temperatures, gadolinium zirconate ceramics prepared in examples 1 to 6, respectively, were subjected to hardness test (using vickers hardness indentation method test) as shown in fig. 5. Wherein, fig. 5(a) is a curve of variation of vickers hardness of gadolinium zirconate ceramic for solidifying TRPO simulation waste along with temperature, and fig. 5(a) shows that when the solid solution amount of TRPO simulation waste is 10-30 wt%, the temperature is gradually increased to 1300 ℃, the vickers hardness is not greatly changed, when the temperature reaches 1400 ℃, the hardness is obviously increased, and for gadolinium zirconate ceramic with 40-60 wt% of TRPO simulation waste solid solution amount, the hardness is in a trend of obviously increasing along with the increase of sintering temperature; FIG. 5(b) is a curve of Vickers hardness of gadolinium zirconate ceramics for solidifying TRPO simulation waste along with the change of solidification amount, and FIG. 5(b) shows that when the sintering temperature is 1200 ℃, the hardness of gadolinium zirconate ceramics is reduced along with the increase of solid solution amount of TRPO simulation waste when the solid solution amount of TRPO simulation waste is 0-50 wt%, and the hardness of gadolinium zirconate ceramics is increased along with the increase of solid solution amount of TRPO simulation waste when 50 wt% < TRPO simulation waste solid solution amount less than or equal to 60 wt%; when the sintering temperature is 1300 ℃ and 1400 ℃, the hardness of the gadolinium zirconate ceramics is firstly reduced and then increased along with the increase of the solid solution amount of TRPO simulation waste, and the gadolinium zirconate ceramics with the solid solution amount of the TRPO simulation waste of 20 wt% has the lowest hardness.

From the analysis, the method provided by the invention can be used for preparing gadolinium zirconate ceramics for solidifying the TRPO simulation waste with high density and high hardness while realizing solidification of the TRPO simulation waste with high capacity.

It will be appreciated by those of ordinary skill in the art that the embodiments described herein are intended to assist the reader in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited embodiments and examples. Those skilled in the art can make various other specific changes and combinations based on the teachings of the present invention without departing from the spirit of the invention, and these changes and combinations are within the scope of the invention.

Claims

1. A preparation method of gadolinium zirconate ceramic for solidifying TRPO simulation waste is characterized by comprising the following process steps:

(1) preparation of precursor powder

According to the mass percentage of 10-60% of TRPO simulation waste in the precursor powder and Gd₂Zr₂O₇Metering raw materials accounting for 40-90% by mass, and mixing metal oxide or nitrate soluble in nitric acid and Gd in TRPO simulated waste raw materials₂Zr₂O₇Mixing zirconium nitrate and gadolinium nitrate serving as raw materials in nitric acid to form a mixed solution, then preparing primary powder by adopting a citric acid combustion method, grinding the primary powder for the first time, then carrying out primary heat treatment at 800-1000 ℃ to fully combust impurities, then uniformly mixing the powder subjected to the primary heat treatment with nitric acid-insoluble metal oxides in TRPO simulated waste raw materials, then calcining the obtained mixture at 800-1000 ℃ for 4-6 hours to carry out secondary heat treatment, and grinding and sieving the product obtained by the secondary heat treatment to obtain precursor powder;

the TRPO simulation waste is alpha simulation waste containing An, and the element components in the alpha simulation waste containing An comprise, by weight, 3.80 parts of Y, 9.37 parts of Pr, 11.64 parts of Mo, 32.49 parts of Nd, 2.27 parts of Ru, 5.90 parts of Sm, 2.97 parts of Pd, 1.20 parts of Eu, 9.90 parts of La, 1.49 parts of Gd and 19.08 parts of Ce;

(2) preparation of a biscuit

(3) preparation of cured body ceramics

2. The method for preparing gadolinium zirconate ceramic for solidifying TRPO mimic wastes according to claim 1, characterized in that in the step (1), the specific step of the citric acid combustion process is: adding citric acid into the mixed solution, stirring to completely dissolve metal oxides soluble in nitric acid in the TRPO simulated waste or nitrates corresponding to the metal oxides in the TRPO simulated waste, and heating the mixed solution to 250-300 ℃ for presintering for 4-6 hours to obtain primary powder; the citric acid is metered in such a way that one citrate ion complexes three monovalent cations.

3. The method for preparing gadolinium zirconate ceramic for solidifying TRPO simulation waste as claimed in claim 1, wherein in the step (1), the time for the first heat treatment at 800-1000 ℃ after the primary powder is primarily ground is 3-4 h.

4. The method for preparing gadolinium zirconate ceramic for solidifying TRPO simulation waste as claimed in any one of claims 1 to 3, wherein in the step (3), the temperature rising rate is 5-8 ℃/min, and the temperature lowering rate is 5-10 ℃/min.

5. Gadolinium zirconate ceramics solidifying TRPO mimic waste, prepared by the process according to any one of claims 1 to 4.