Method for recovering thallium-doped iodide waste

Abstract

The invention relates to a method for recovering thallium-doped iodide waste, which comprises the following steps: (1) dissolving the thallium-doped iodide waste to obtain a thallium-doped iodide solution; (2) carrying out adsorption treatment on the thallium-doped iodide solution by using activated carbon, and carrying out solid-liquid separation to obtain an iodide solution and iodide residues; (3) concentrating and crystallizing the iodide solution to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to first vacuum heating and first vacuum distillation, and iodide is obtained; and (4) sequentially carrying out second vacuum heating and second vacuum distillation on the iodide slag to obtain thallium iodide. According to the method provided by the invention, thallium in the thallium-doped iodide waste can be separated out, raw material recycling is realized, pollution of the waste to the environment can be reduced, and green circular economy can be realized through resource recycling.

Description

Technical Field

[0001] The invention belongs to the technical field of waste material utilization and relates to a method for recycling waste materials, in particular to a method for recycling thallium-doped iodide waste materials. Background Art

[0002] Thallium-doped cesium iodide (CsI:Tl) scintillation crystal is a colorless and transparent cubic crystal with cesium iodide as the matrix material and doped with appropriate thallium. Thallium-doped cesium iodide scintillation crystal belongs to halide scintillator, which has the characteristics of high density, high average coefficient, low melting point and high luminous efficiency. It can be used to make various detectors and is widely used in nuclear physics, nuclear medical imaging, geological exploration, industrial non-destructive testing or security inspection and other fields.

[0003] Thallium-doped sodium iodide (NaI:Tl) scintillator crystal is a colorless transparent cubic crystal with sodium iodide as the matrix material and appropriately doped with thallium. Thallium-doped sodium iodide scintillator crystal has the characteristics of high density, high atomic number, high luminous efficiency, good Compton effect, good matching degree between luminous wavelength and photodiode, strong absorption capacity for X-ray and gamma ray, and high energy resolution. It is a scintillator with excellent performance. In addition to being used in the medical field, it can also be used in nuclear physics, petroleum exploration, geological exploration, industrial testing, environmental monitoring and safety inspection.

[0004] If thallium-doped iodide crystals such as thallium-doped sodium iodide and thallium-doped cesium iodide leak during the growth process, the leaked material cannot be used directly. Thallium-doped iodide crystals will also produce some scraps and waste materials during the processing process, and these raw materials cannot be used directly either. In addition, thallium iodide is highly toxic and its industrial application is strictly controlled. In order to avoid the threat of thallium iodide to public health, the thallium iodide in the waste needs to be recovered.

[0005] Therefore, it is necessary to provide a method for recycling thallium-doped iodide waste to separate thallium iodide and avoid environmental pollution; at the same time, the iodide can be recycled to obtain iodide with a purity of more than 4N. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for recovering thallium-doped iodide waste, which can separate thallium from thallium-doped iodide waste, not only reducing the pollution of the waste to the environment, but also recovering iodide above 4N, thereby realizing a green circular economy.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for recovering thallium-doped iodide waste, the method comprising the following steps:

[0009] (1) dissolving thallium-doped iodide waste to obtain thallium-doped iodide solution, wherein the thallium-doped iodide waste is waste generated in the iodide crystallization process.

[0010] (2) Activated carbon adsorption treatment step (1) The thallium-doped iodide solution is subjected to solid-liquid separation to obtain an iodide solution and iodide slag.

[0011] (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to a first vacuum heating and a first vacuum distillation to obtain iodide.

[0012] (4) The iodide slag in step (2) is subjected to a second vacuum heating and a second vacuum distillation in sequence to obtain thallium iodide.

[0013] Step (3) and step (4) are performed in no particular order.

[0014] The method provided by the present invention can recover iodide with a purity of 4N or more (≥99.99wt%) by performing concentration crystallization, first vacuum heating and first vacuum distillation on an iodide solution; since thallium iodide is slightly soluble in water, most of the thallium iodide enters the iodide slag during solid-liquid separation, and then second vacuum heating and second vacuum distillation are performed in sequence to obtain thallium iodide with a purity of 4N or more; therefore, the method provided by the present invention can separate thallium from thallium-doped iodide waste, realize the recycling of raw materials, not only can reduce the pollution of waste to the environment, but also can recover iodide with a purity of 4N or more, and realize green circular economy.

[0015] Preferably, the temperature of the first vacuum heating in step (3) is 300°C-320°C.

[0016] Preferably, the first vacuum heating time in step (3) is 10 h to 12 h.

[0017] Preferably, the absolute pressure of the first vacuum heating in step (3) is ≤3×10 3 Pa.

[0018] Preferably, the absolute pressure of the first vacuum distillation in step (3) is ≤3×10 -3 Pa.

[0019] Preferably, the thallium iodide-doped waste material is thallium iodide-doped sodium iodide waste material or thallium iodide-doped cesium iodide waste material.

[0020] Preferably, when the thallium-doped iodide waste is thallium-doped sodium iodide waste, the first vacuum distillation in step (3) comprises first obtaining thallium iodide at a temperature of 450° C. to 470° C., and then obtaining sodium iodide at a temperature of 700° C. to 720° C.

[0021] Preferably, when the thallium-doped iodide waste is thallium-doped cesium iodide waste, the first vacuum distillation in step (3) comprises first obtaining thallium iodide at a temperature of 450°C-470°C, and then obtaining cesium iodide at a temperature of 650°C-680°C.

[0022] Preferably, the temperature of the second vacuum heating in step (4) is 300°C-320°C.

[0023] Preferably, the second vacuum heating time in step (4) is 3h-4h.

[0024] Preferably, the absolute pressure of the second vacuum heating in step (4) is ≤3×10 3 Pa.

[0025] Preferably, the temperature of the second vacuum distillation in step (4) is 450°C-470°C.

[0026] Preferably, the time of the second vacuum distillation in step (4) is 3h-5h.

[0027] Preferably, the absolute pressure of the second vacuum distillation in step (4) is ≤3×10 -3 Pa.

[0028] Preferably, the thallium-doped iodide solution in step (1) is a saturated thallium-doped iodide solution.

[0029] Preferably, the activated carbon used in the activated carbon adsorption treatment has the following requirements: ash content ≤ 5wt%, iodine adsorption value ≥ 600mg / g, and average particle size ≥ 5mm.

[0030] Preferably, the solid-liquid separation method comprises suction filtration.

[0031] As a preferred technical solution of the method provided by the present invention, the method comprises the following steps:

[0032] (1) dissolving thallium-doped iodide waste to obtain a thallium-doped iodide solution;

[0033] The thallium-doped iodide waste material is thallium-doped sodium iodide waste material or thallium-doped cesium iodide waste material.

[0034] (2) Activated carbon adsorption treatment step (1) The thallium-doped iodide solution is filtered to obtain an iodide solution and iodide slag.

[0035] (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to a first vacuum heating and a first vacuum distillation to obtain iodide.

[0036] The absolute pressure of the first vacuum distillation is ≤3×10 -3 Pa.

[0037] When the thallium-doped iodide waste is thallium-doped sodium iodide waste, the first vacuum distillation in step (3) includes first obtaining thallium iodide at a temperature of 450°C-470°C, and then obtaining sodium iodide at a temperature of 700°C-720°C.

[0038] When the thallium-doped iodide waste is thallium-doped cesium iodide waste, the first vacuum distillation in step (3) comprises first obtaining thallium iodide at a temperature of 450°C-470°C, and then obtaining cesium iodide at a temperature of 650°C-680°C.

[0039] (4) The iodide slag of step (2) is subjected to a second vacuum heating and a second vacuum distillation in sequence to obtain thallium iodide; the temperature of the second vacuum heating is 300° C.-320° C., and the absolute pressure is ≤3×10 3 Pa, time is 3h-4h; the temperature of the second vacuum distillation is 450℃-470℃, absolute pressure ≤3×10 -3 Pa, time is 3h-5h.

[0040] Step (3) and step (4) are performed in no particular order.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The method provided by the present invention can recover iodide with a purity of more than 4N by performing concentration crystallization, first vacuum heating and first vacuum distillation on an iodide solution; since thallium iodide is slightly soluble in water, most of the thallium iodide enters the iodide slag during solid-liquid separation, and then second vacuum heating and second vacuum distillation are performed in sequence to separate thallium iodide with a purity of more than 4N; therefore, the method provided by the present invention can separate thallium from thallium-doped iodide waste, not only can the pollution of the waste to the environment be reduced, but also iodide with a purity of more than 4N can be recovered, thereby realizing a green circular economy. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0044] A certain embodiment of the present invention provides a method for recovering thallium-doped iodide waste, the method comprising the following steps:

[0045] (1) Dissolving thallium-doped iodide waste to obtain a thallium-doped iodide solution.

[0046] (2) Activated carbon adsorption treatment step (1) The thallium-doped iodide solution is subjected to solid-liquid separation to obtain an iodide solution and iodide slag.

[0047] (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to a first vacuum heating and a first vacuum distillation to obtain iodide.

[0048] (4) The iodide slag in step (2) is subjected to a second vacuum heating and a second vacuum distillation in sequence to obtain thallium iodide.

[0049] Step (3) and step (4) are performed in no particular order.

[0050] The method provided by the present invention can recover iodide with a purity of more than 4N by performing concentration crystallization, first vacuum heating and first vacuum distillation on an iodide solution; since thallium iodide is slightly soluble in water, most of the thallium iodide enters the iodide slag during solid-liquid separation, and then second vacuum heating and second vacuum distillation are performed in sequence to obtain thallium iodide with a purity of more than 4N; therefore, the method provided by the present invention can separate thallium from thallium-doped iodide waste, realize the recycling of raw materials, reduce the pollution of waste to the environment, and realize a green circular economy.

[0051] In some embodiments, the temperature of the first vacuum heating in step (3) is 300°C-320°C, for example, 300°C, 305°C, 310°C, 315°C or 320°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0052] In certain embodiments, the time of the first vacuum heating in step (3) is 10 h-12 h, for example, 10 h, 10.5 h, 11 h, 11.5 h or 12 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0053] In some embodiments, the absolute pressure of the first vacuum heating in step (3) is ≤3×10 3 Pa, for example, can be 0.1×10 3 Pa, 0.5×10 3 Pa, 1×10 3 Pa, 1.5×10 3 Pa, 2×10 3 Pa, 2.5×10 3 Pa or 3×10 3 Pa, but not limited to the listed values, other values ​​not listed in the numerical range are also applicable, preferably ≤1×10 3 Pa.

[0054] The present invention removes crystal water in iodide crystal particles through the first vacuum heating.

[0055] In certain embodiments, the absolute pressure of the first vacuum distillation in step (3) is ≤3×10 -3 Pa, for example, can be 0.5×10 -3 Pa, 1×10 -3 Pa, 1.5×10 -3 Pa, 2×10 -3 Pa, 2.5×10 -3 Pa or 3×10 -3 Pa, but not limited to the listed values, other values ​​not listed in the numerical range are also applicable, preferably ≤1×10 -3 Pa.

[0056] In some embodiments, the thallium-doped iodide waste is thallium-doped sodium iodide waste or thallium-doped cesium iodide waste.

[0057] In certain embodiments, when the thallium-doped iodide waste is thallium-doped sodium iodide waste, the first vacuum distillation in step (3) comprises first obtaining thallium iodide at a temperature of 450° C. to 470° C., and then obtaining sodium iodide at a temperature of 700° C. to 720° C.;

[0058] In certain embodiments, when the thallium-doped iodide waste is thallium-doped cesium iodide waste, the first vacuum distillation in step (3) includes first obtaining thallium iodide at a temperature of 450°C-470°C, and then obtaining cesium iodide at a temperature of 650°C-680°C.

[0059] The temperature of the first vacuum distillation to obtain thallium iodide is 450°C-470°C, for example, it can be 450°C, 455°C, 460°C, 465°C or 470°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0060] Taking sodium iodide as an example, the temperature of the first vacuum distillation to obtain sodium iodide is 700°C-720°C, for example, it can be 700°C, 705°C, 710°C, 715°C or 720°C, but is not limited to the listed values, and the remaining unlisted values ​​within the numerical range are also applicable.

[0061] Taking cesium iodide as an example, the temperature of the first vacuum distillation to obtain sodium iodide is 650°C-680°C, for example, it can be 650°C, 660°C, 670°C or 680°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0062] In certain embodiments, the temperature of the second vacuum heating in step (4) is 300°C-320°C, for example, 300°C, 305°C, 310°C, 315°C or 320°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0063] In certain embodiments, the time of the second vacuum heating in step (4) is 3h-4h, for example, 3h, 3.2h, 3.5h, 3.8h or 4h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] In certain embodiments, the absolute pressure of the second vacuum heating in step (4) is ≤3×10 -3 Pa, for example, can be 0.5×10 -3 Pa, 1×10 -3 Pa, 1.5×10 -3 Pa, 2×10 -3 Pa, 2.5×10 -3 Pa or 3×10 -3 Pa, but not limited to the listed values, other values ​​not listed in the numerical range are also applicable, preferably ≤1×10 -3 Pa.

[0065] In certain embodiments, the temperature of the second vacuum distillation in step (4) is 450°C-470°C, for example, 450°C, 455°C, 460°C, 465°C or 470°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0066] In certain embodiments, the time of the second vacuum distillation in step (4) is 3h-5h, for example, 3h, 3.5h, 4h, 4.5h or 5h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0067] In certain embodiments, the absolute pressure of the second vacuum distillation in step (4) is ≤3×10 -3 Pa, for example, can be 0.5×10 -3 Pa, 1×10 -3 Pa, 1.5×10 -3 Pa, 2×10 -3 Pa, 2.5×10 -3 Pa or 3×10 -3 Pa, but not limited to the listed values, other values ​​not listed in the numerical range are also applicable, preferably ≤1×10 -3 Pa.

[0068] In some embodiments, the thallium-doped iodide solution in step (1) is a saturated thallium-doped iodide solution.

[0069] In certain embodiments, the activated carbon used in the activated carbon adsorption treatment has the following requirements: ash content ≤ 5wt%, iodine adsorption value ≥ 600mg / g, and average particle size ≥ 5mm.

[0070] In certain embodiments, the solid-liquid separation method comprises suction filtration.

[0071] As a preferred embodiment of the method provided by the present invention, the method comprises the following steps:

[0072] (1) Dissolving thallium-doped iodide waste to obtain a thallium-doped iodide solution.

[0073] The thallium-doped iodide waste material is thallium-doped sodium iodide waste material or thallium-doped cesium iodide waste material.

[0074] (2) Activated carbon adsorption treatment step (1) The thallium-doped iodide solution is filtered to obtain an iodide solution and iodide slag.

[0075] (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to a first vacuum heating and a first vacuum distillation to obtain iodide.

[0076] The temperature of the first vacuum heating is 300°C-320°C, and the absolute pressure is ≤1×10 3 Pa, time is 10h-12h.

[0077] The absolute pressure of the first vacuum distillation is ≤3×10 -3 Pa.

[0078] When the thallium-doped iodide waste is thallium-doped sodium iodide waste, the first vacuum distillation in step (3) includes first obtaining thallium iodide at a temperature of 450°C-470°C, and then obtaining sodium iodide at a temperature of 700°C-720°C.

[0079] When the thallium-doped iodide waste is thallium-doped cesium iodide waste, the first vacuum distillation in step (3) comprises first obtaining thallium iodide at a temperature of 450°C-470°C, and then obtaining cesium iodide at a temperature of 650°C-680°C.

[0080] (4) The iodide slag of step (2) is subjected to a second vacuum heating and a second vacuum distillation in sequence to obtain thallium iodide; the temperature of the second vacuum heating is 300° C.-320° C., and the absolute pressure is ≤3×10 3 Pa, time is 3h-4h; the temperature of the second vacuum distillation is 450℃-470℃, absolute pressure ≤3×10 -3 Pa, time is 3h-5h.

[0081] Step (3) and step (4) are performed in no particular order.

[0082] In order to clearly illustrate the technical solution of the present invention, the purity in the following test example is measured by glow discharge point mass spectrometry (GDMS), and the recovery rate is the mass percentage of the recovered iodide mass to the corresponding iodide mass in the waste; the ash content of the activated carbon used in the following test example is 4wt%, the iodine adsorption value is 620mg / g, and the average particle size is 6mm.

[0083] Test Example 1

[0084] This test example provides a method for recovering thallium-doped iodide waste, the method comprising the following steps:

[0085] (1) dissolving waste material of thallium-doped sodium iodide (the mass percentage of sodium iodide is 82.9wt%, and the mass percentage of thallium iodide is 0.42wt%) to obtain a saturated solution of thallium-doped iodide.

[0086] (2) The saturated thallium-doped iodide solution in step (1) is filtered to obtain an iodide solution and iodide slag.

[0087] (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to a first vacuum heating and a first vacuum distillation to obtain iodide.

[0088] The temperature of the first vacuum heating is 310°C and the absolute pressure is 3×10 3 Pa, the time is 11h.

[0089] The first vacuum distillation consisted of distilling at an absolute pressure of 3 × 10 -3 Pa conditions, first at 460 ° C to obtain thallium iodide, and then at 710 ° C to obtain sodium iodide.

[0090] (4) The iodide slag of step (2) is subjected to a second vacuum heating and a second vacuum distillation in sequence to obtain thallium iodide; the temperature of the second vacuum heating is 310° C., and the absolute pressure is 3×10 3 Pa, time is 3.5h; the temperature of the second vacuum distillation is 460℃, the absolute pressure is 3×10 -3 Pa, time is 4h.

[0091] Test Example 2

[0092] This test example provides a method for recovering thallium-doped iodide waste, the method comprising the following steps:

[0093] (1) Dissolve the same thallium-doped sodium iodide waste as in Test Example 1 to obtain a thallium-doped sodium iodide saturated solution.

[0094] (2) The saturated thallium-doped iodide solution in step (1) is filtered to obtain an iodide solution and iodide slag.

[0095] (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to a first vacuum heating and a first vacuum distillation to obtain iodide.

[0096] The temperature of the first vacuum heating is 300°C and the absolute pressure is 3×10 3 Pa, the time is 12h.

[0097] The first vacuum distillation consisted of distilling at an absolute pressure of 3 × 10 -3 Under the conditions of Pa, thallium iodide is first obtained at a temperature of 450°C, and then sodium iodide is obtained at a temperature of 700°C.

[0098] (4) The iodide slag in step (2) is subjected to a second vacuum heating and a second vacuum distillation in sequence to obtain thallium iodide; the temperature of the second vacuum heating is 300° C. and the absolute pressure is 3×10 3 Pa, time is 4h; the temperature of the second vacuum distillation is 450℃, the absolute pressure is 3×10 -3 Pa, time is 5h.

[0099] Test Example 3

[0100] This test example provides a method for recovering thallium-doped iodide waste, the method comprising the following steps:

[0101] (1) Dissolve the same thallium-doped sodium iodide waste as in Test Example 1 to obtain a thallium-doped sodium iodide saturated solution.

[0102] (2) The saturated thallium-doped iodide solution in step (1) is filtered to obtain an iodide solution and iodide slag.

[0103] (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to a first vacuum heating and a first vacuum distillation to obtain iodide.

[0104] The temperature of the first vacuum heating is 320°C and the absolute pressure is 3×10 3 Pa, the time is 12h.

[0105] The first vacuum distillation consisted of distilling at an absolute pressure of 3 × 10 -3 Pa conditions, first at 470 ° C to obtain thallium iodide, and then at 720 ° C to obtain sodium iodide.

[0106] (4) The iodide slag in step (2) is subjected to a second vacuum heating and a second vacuum distillation in sequence to obtain thallium iodide; the temperature of the second vacuum heating is 320° C., and the absolute pressure is 3×10 3 Pa, time is 3h; the temperature of the second vacuum distillation is 470℃, the absolute pressure is 3×10 -3 Pa, time is 3h.

[0107] Test Example 4

[0108] This test example provides a method for recovering thallium-doped iodide waste, which is the same as that of test example 1 except that the temperature of the first vacuum distillation to obtain thallium iodide and the temperature of the second vacuum distillation are 440°C.

[0109] Test Example 5

[0110] This test example provides a method for recovering thallium-doped iodide waste, which is the same as that of test example 1 except that the temperature of the first vacuum distillation to obtain thallium iodide and the temperature of the second vacuum distillation are 480°C.

[0111] Test Example 6

[0112] This test example provides a method for recovering thallium-doped iodide waste, which is the same as that of test example 1 except that the temperature of obtaining sodium iodide by the first vacuum distillation is 690°C.

[0113] Test Example 7

[0114] This test example provides a method for recovering thallium-doped iodide waste, which is the same as that of test example 1 except that the temperature of obtaining sodium iodide by the first vacuum distillation is 730°C.

[0115] Test Example 8

[0116] This test example provides a method for recovering thallium-doped iodide waste, the method comprising the following steps:

[0117] (1) Dissolve the same thallium-doped sodium iodide waste as in Test Example 1 to obtain a thallium-doped sodium iodide saturated solution.

[0118] (2) The saturated thallium-doped iodide solution in step (1) is filtered to obtain an iodide solution and iodide slag.

[0119] (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are subjected to a first vacuum distillation to obtain iodide.

[0120] The first vacuum distillation consisted of distilling at an absolute pressure of 3 × 10 -3Pa conditions, first at 460 ° C to obtain thallium iodide, and then at 710 ° C to obtain sodium iodide.

[0121] (4) The iodide slag of step (2) is subjected to a second vacuum distillation to obtain thallium iodide; the temperature of the second vacuum distillation is 460°C and the absolute pressure is 3×10 -3 Pa, time is 4h.

[0122] The purity and recovery rate of thallium iodide obtained in the above-mentioned Test Examples 1 to 8 and the purity and recovery rate of sodium iodide were measured, and the results are shown in Table 1, where the purity of thallium iodide is the purity of thallium iodide obtained by mixing the first vacuum distillation and the second vacuum distillation.

[0123] Table 1

[0124]

[0125] Test Example 9

[0126] This test example provides a method for recovering thallium-doped iodide waste, the method comprising the following steps:

[0127] (1) Dissolving waste material doped with thallium iodide (mass percentage of cesium iodide is 83.5 wt % and mass percentage of thallium iodide is 0.56 wt %) to obtain a saturated solution of thallium iodide.

[0128] (2) The saturated thallium-doped iodide solution in step (1) is filtered to obtain an iodide solution and iodide slag.

[0129] (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to a first vacuum heating and a first vacuum distillation to obtain iodide.

[0130] The temperature of the first vacuum heating is 310°C and the absolute pressure is 3×10 3 Pa, the time is 11h.

[0131] The first vacuum distillation consisted of distilling at an absolute pressure of 3 × 10 -3 Under the conditions of Pa, thallium iodide is first obtained at a temperature of 460°C, and then cesium iodide is obtained at a temperature of 660°C.

[0132] (4) The iodide slag of step (2) is subjected to a second vacuum heating and a second vacuum distillation in sequence to obtain thallium iodide; the temperature of the second vacuum heating is 310° C., and the absolute pressure is 3×10 3 Pa, time is 3.5h; the temperature of the second vacuum distillation is 460℃, the absolute pressure is 3×10 -3Pa, time is 4h.

[0133] Test Example 10

[0134] This test example provides a method for recovering thallium-doped iodide waste, the method comprising the following steps:

[0135] (1) Dissolve the same thallium-doped cesium iodide waste as in Test Example 9 to obtain a saturated solution of thallium-doped iodide.

[0136] (2) The saturated thallium-doped iodide solution in step (1) is filtered to obtain an iodide solution and iodide slag.

[0137] (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to a first vacuum heating and a first vacuum distillation to obtain iodide.

[0138] The temperature of the first vacuum heating is 300°C and the absolute pressure is 3×10 3 Pa, the time is 12h.

[0139] The first vacuum distillation consisted of distilling at an absolute pressure of 3 × 10 -3 Under the conditions of Pa, thallium iodide is first obtained at a temperature of 450°C, and then cesium iodide is obtained at a temperature of 650°C.

[0140] (4) The iodide slag in step (2) is subjected to a second vacuum heating and a second vacuum distillation in sequence to obtain thallium iodide; the temperature of the second vacuum heating is 300° C. and the absolute pressure is 3×10 3 Pa, time is 4h; the temperature of the second vacuum distillation is 450℃, the absolute pressure is 3×10 -3 Pa, time is 5h.

[0141] Test Example 11

[0142] This test example provides a method for recovering thallium-doped iodide waste, the method comprising the following steps:

[0143] (1) Dissolve the same thallium-doped cesium iodide waste as in Test Example 9 to obtain a saturated solution of thallium-doped iodide.

[0144] (2) The saturated thallium-doped iodide solution in step (1) is filtered to obtain an iodide solution and iodide slag.

[0145] (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to a first vacuum heating and a first vacuum distillation to obtain iodide.

[0146] The temperature of the first vacuum heating is 320°C and the absolute pressure is 1×10 3 Pa, the time is 12h.

[0147] The first vacuum distillation consisted of distilling at an absolute pressure of 3 × 10 -3 Under the conditions of Pa, thallium iodide is first obtained at a temperature of 470°C, and then cesium iodide is obtained at a temperature of 680°C.

[0148] (4) The iodide slag of step (2) is subjected to a second vacuum heating and a second vacuum distillation in sequence to obtain thallium iodide; the temperature of the second vacuum heating is 320° C., and the absolute pressure is 1×10 3 Pa, time is 3h; the temperature of the second vacuum distillation is 470℃, the absolute pressure is 3×10 -3 Pa, time is 3h.

[0149] Test Example 12

[0150] This test example provides a method for recovering thallium-doped iodide waste, which is the same as that of Test Example 9 except that the temperature of cesium iodide obtained by the first vacuum distillation is 640°C.

[0151] Test Example 13

[0152] This test example provides a method for recovering thallium-doped iodide waste, which is the same as that of Test Example 9 except that the temperature of cesium iodide obtained by the first vacuum distillation is 690°C.

[0153] Test Example 14

[0154] This test example provides a method for recovering thallium-doped iodide waste, the method comprising the following steps:

[0155] (1) Dissolve the same thallium-doped cesium iodide waste as in Test Example 9 to obtain a saturated solution of thallium-doped iodide.

[0156] (2) The saturated thallium-doped iodide solution in step (1) is filtered to obtain an iodide solution and iodide slag.

[0157] (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are subjected to a first vacuum distillation to obtain iodide.

[0158] The first vacuum distillation consisted of distilling at an absolute pressure of 3 × 10 -3 Under the conditions of Pa, thallium iodide is first obtained at a temperature of 460°C, and then cesium iodide is obtained at a temperature of 660°C.

[0159] (4) The iodide slag of step (2) is subjected to a second vacuum distillation to obtain thallium iodide; the temperature of the second vacuum distillation is 460°C and the absolute pressure is 3×10 -3 Pa, time is 4h.

[0160] The purity and recovery rate of thallium iodide obtained in Experimental Examples 9 to 14 and the purity and recovery rate of cesium iodide were measured, and the results are shown in Table 2, where the purity of thallium iodide is the purity of thallium iodide obtained by mixing the first vacuum distillation and the second vacuum distillation.

[0161] Table 2

[0162]

[0163] In summary, the method provided by the present invention can recover iodide with a purity of more than 4N by performing concentration crystallization, first vacuum heating and first vacuum distillation on the iodide solution; since thallium iodide is slightly soluble in water, most of the thallium iodide enters the iodide slag during solid-liquid separation, and then the second vacuum heating and the second vacuum distillation are performed in sequence to obtain thallium iodide with a purity of more than 4N; therefore, the method provided by the present invention can recover thallium in thallium-doped iodide waste, realize the recycling of raw materials, not only can reduce the pollution of waste to the environment, but also can realize a green circular economy through resource recycling and reuse.

[0164] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for recovering thallium-doped iodide waste, characterized in that: The method comprises the following steps: (1) dissolving thallium-doped iodide waste to obtain a thallium-doped iodide solution; (2) treating the thallium-doped iodide solution in step (1) by activated carbon adsorption, separating the solid from the liquid to obtain an iodide solution and iodide slag; (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; The iodide crystal particles are subjected to a first vacuum heating and a first vacuum distillation in sequence to obtain iodide; (4) The iodide slag in step (2) is subjected to a second vacuum heating and a second vacuum distillation in sequence to obtain thallium iodide; Step (3) and step (4) are performed in no particular order.

2. The method according to claim 1, characterized in that: Step (3) The temperature of the first vacuum heating is 300° C.-320° C.; And / or, the first vacuum heating time in step (3) is 10h-12h; And / or, the absolute pressure of the first vacuum heating in step (3) is ≤3×10 3 Pa.

3. The method according to claim 1, characterized in that Step (3) The absolute pressure of the first vacuum distillation is ≤3×10 -3 Pa.

4. The method according to any one of claims 1 to 3, characterized in that: The thallium-doped iodide waste is thallium-doped sodium iodide waste or thallium-doped cesium iodide waste; And / or, when the thallium-doped iodide waste is thallium-doped sodium iodide waste, the first vacuum distillation in step (3) comprises first obtaining thallium iodide at a temperature of 450° C. to 470° C., and then obtaining sodium iodide at a temperature of 700° C. to 720° C.; And / or, when the thallium-doped iodide waste is thallium-doped cesium iodide waste, the first vacuum distillation in step (3) comprises first obtaining thallium iodide at a temperature of 450°C-470°C, and then obtaining cesium iodide at a temperature of 650°C-680°C.

5. The method according to claim 1, characterized in that: Step (4) the temperature of the second vacuum heating is 300° C.-320° C.; And / or, the second vacuum heating time in step (4) is 3h-4h; And / or, the absolute pressure of the second vacuum heating in step (4) is ≤3×10 3 Pa.

6. The method according to claim 1, characterized in that Step (4) the temperature of the second vacuum distillation is 450° C.-470° C.; And / or, the time of the second vacuum distillation in step (4) is 3h-5h; And / or, the absolute pressure of the second vacuum distillation in step (4) is ≤3×10 -3 Pa.

7. The method according to claim 1, characterized in that The thallium-doped iodide solution in step (1) is a saturated thallium-doped iodide solution.

8. The method according to claim 1, characterized in that The activated carbon used in the activated carbon adsorption treatment has the following requirements: ash content ≤ 5wt%, iodine adsorption value ≥ 600mg / g, and average particle size ≥ 5mm.

9. The method according to claim 1, characterized in that: The solid-liquid separation method includes suction filtration.

10. The method according to claim 1, characterized in that The method comprises the following steps: (1) dissolving thallium-doped iodide waste to obtain a thallium-doped iodide solution; The thallium-doped iodide waste is thallium-doped sodium iodide waste or thallium-doped cesium iodide waste; (2) treating the thallium-doped iodide solution in step (1) by activated carbon adsorption, filtering, and obtaining an iodide solution and iodide slag; (3) The iodide solution in step (2) is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to a first vacuum heating and a first vacuum distillation to obtain iodide; The temperature of the first vacuum heating is 300°C-320°C, and the absolute pressure is ≤3×10 3 Pa, time is 10h-12h; The absolute pressure of the first vacuum distillation is ≤3×10 -3 Pa; When the thallium-doped iodide waste is thallium-doped sodium iodide waste, the first vacuum distillation in step (3) comprises first obtaining thallium iodide at a temperature of 450° C. to 470° C., and then obtaining sodium iodide at a temperature of 700° C. to 720° C.; When the thallium-doped iodide waste is thallium-doped cesium iodide waste, the first vacuum distillation in step (3) comprises first obtaining thallium iodide at a temperature of 450° C. to 470° C., and then obtaining cesium iodide at a temperature of 650° C. to 680° C.; (4) The iodide slag of step (2) is subjected to a second vacuum heating and a second vacuum distillation in sequence to obtain thallium iodide; the temperature of the second vacuum heating is 300° C.-320° C., and the absolute pressure is ≤3×10 3 Pa, time is 3h-4h; the temperature of the second vacuum distillation is 450℃-470℃, absolute pressure ≤3×10 -3 Pa, time is 3h-5h; Step (3) and step (4) are performed in no particular order.

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