Method for recovering iodide waste

Abstract

The invention relates to a method for recovering iodide waste, which comprises the following steps: carrying out activated carbon adsorption treatment on dissolved iodide waste, and carrying out solid-liquid separation to obtain an iodide solution; concentrating and crystallizing the iodide solution to obtain iodide crystal particles; the iodide crystal particles are sequentially subjected to vacuum heating and vacuum distillation, and the iodide with the purity being 4N or above is obtained. According to the method, other materials do not need to be added during recycling, the iodide with the purity of 4N or above can be obtained, waste recycling is achieved, the cost is reduced, pollution of the waste to the environment can be reduced, and green circulation is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of waste treatment and relates to a waste recovery method, in particular to an iodide waste recovery method. Background Art

[0002] Cesium iodide crystal is a halide crystal with excellent performance. It has the advantages of low melting point (only 621℃), mature growth technology, easy growth of large-sized crystals and low price, making it widely used in high-energy physics, safety inspection, industrial non-destructive testing, and nuclear medical imaging. Sodium iodide crystal has high density, high photon yield and relatively low cost. It is widely used in nuclear medicine, environmental monitoring, oil well exploration and other fields. Due to its excellent energy resolution and high light output, it can also be used in gamma cameras and positron emission tomography (PET).

[0003] If iodide crystals such as cesium iodide and sodium iodide leak during the growth process, the leaked materials cannot be used directly. Iodide crystals also produce some scraps and waste materials during the processing process, which also cannot be used directly. Therefore, it is necessary to recycle the leaked and waste materials so that they can be reused.

[0004] Therefore, it is necessary to provide a method for recycling iodide waste and make the purity of the recycled iodide above 4N. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for recycling iodide waste, which does not require the addition of other materials during recycling and can obtain iodide with a purity of more than 4N (≥99.99wt%), thereby achieving the recycling of waste materials, reducing costs, and reducing the pollution of the waste to the environment, thereby achieving a green cycle.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for recovering iodide waste, the method comprising the following steps:

[0008] The dissolved iodide waste is treated with activated carbon adsorption and solid-liquid separation to obtain an iodide solution; the iodide solution is concentrated and crystallized to obtain iodide crystal particles; the iodide crystal particles are successively subjected to vacuum heating and vacuum distillation to obtain iodide with a purity of more than 4N. The iodide waste is waste generated during the growth of iodide crystals.

[0009] The method provided by the present invention does not need to add other materials during recycling, and can obtain iodide with a purity of more than 4N, thereby realizing the recycling of waste materials, reducing costs, and reducing the pollution of waste materials to the environment, thereby realizing green circulation.

[0010] Preferably, the iodide waste includes cesium iodide waste or sodium iodide waste.

[0011] Preferably, the vacuum heating temperature is 300°C-320°C.

[0012] Preferably, the vacuum heating time is more than 10 hours.

[0013] Preferably, the absolute pressure of the vacuum heating is ≤3×10 3 Pa, preferably ≤1×10 3 Pa.

[0014] Preferably, the absolute pressure of the vacuum distillation is ≤3×10 -3 Pa, preferably ≤1×10 -3 Pa.

[0015] Preferably, when the iodide waste is cesium iodide waste, the temperature of the vacuum distillation is 650°C-680°C.

[0016] Preferably, when the iodide waste is sodium iodide waste, the temperature of the vacuum distillation is 700°C-720°C.

[0017] Preferably, the iodide waste also includes thallium iodide waste.

[0018] Preferably, when the iodide waste also includes thallium iodide waste, the vacuum heating temperature is 300°C-320°C; the vacuum heating time is more than 10 hours; the absolute pressure of the vacuum heating is ≤3×10 3 Pa, preferably ≤1×10 3 Pa.

[0019] Preferably, when the iodide waste also includes thallium iodide waste, the absolute pressure of the vacuum distillation is ≤3×10 -3 Pa, preferably ≤1×10 -3 Pa.

[0020] Preferably, the vacuum distillation comprises a first distillation and a second distillation performed sequentially; the first distillation recovers thallium iodide; and the second distillation recovers cesium iodide or sodium iodide.

[0021] Preferably, the temperature of the first distillation to recover thallium iodide is 450°C-470°C.

[0022] Preferably, the temperature of the second distillation to recover cesium iodide is 650°C-680°C.

[0023] Preferably, the temperature of the second distillation to recover sodium iodide is 700°C-720°C.

[0024] Preferably, the solution obtained after dissolving the iodide waste material is a saturated aqueous solution.

[0025] 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.

[0026] Preferably, the solid-liquid separation method comprises suction filtration.

[0027] As one of the preferred technical solutions of the method provided by the present invention, the method comprises the following steps:

[0028] (1) dissolving cesium iodide waste in water to obtain saturated cesium iodide waste liquid;

[0029] (2) adding activated carbon to the cesium iodide waste liquid, stirring and adsorbing, and then filtering to obtain a cesium iodide solution;

[0030] (3) The cesium iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0031] (4) The iodide crystal particles are at an absolute pressure of ≤3×10 3 Pa, and the temperature is 300℃-320℃, and the vacuum heating is carried out for more than 10h to remove the crystal water; then the absolute pressure is ≤3×10 -3 Pa, vacuum distillation at a temperature of 650°C-680°C to obtain cesium iodide with a purity of more than 4N.

[0032] As the second preferred technical solution of the method provided by the present invention, the method comprises the following steps:

[0033] (1) sodium iodide waste material is dissolved in water to obtain saturated sodium iodide waste liquid;

[0034] (2) adding activated carbon to the sodium iodide waste liquid, stirring and adsorbing, and then filtering to obtain a sodium iodide solution;

[0035] (3) The sodium iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0036] (4) The iodide crystal particles are at an absolute pressure of ≤3×10 3 Pa, and the temperature is 300℃-320℃, and the vacuum heating is carried out for more than 10h to remove the crystal water; then the absolute pressure is ≤3×10 -3Pa, vacuum distillation at a temperature of 700°C-720°C to obtain sodium iodide with a purity of more than 4N.

[0037] As the third preferred technical solution of the method provided by the present invention, the method comprises the following steps:

[0038] (I) dissolving a combined waste material consisting of sodium iodide waste material and thallium iodide waste material in water to obtain a saturated waste liquid;

[0039] (II) adding activated carbon to the saturated waste liquid, stirring and adsorbing, and then filtering to obtain an iodide solution;

[0040] (III) the iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0041] (IV) The iodide crystal particles are at an absolute pressure of ≤1×10 3 Pa, and the temperature is 300℃-320℃, and the vacuum heating is carried out for 10h-12h to remove the crystal water; then the absolute pressure is ≤3×10 -3 Pa, the temperature is 450℃-470℃, and the first distillation is carried out to obtain thallium iodide with a purity of more than 4N; and the absolute pressure is ≤3×10 -3 Pa, and a second distillation at a temperature of 700°C-720°C to obtain sodium iodide with a purity of more than 4N.

[0042] As a fourth preferred technical solution of the method provided by the present invention, the method comprises the following steps:

[0043] (I) dissolving a combined waste material consisting of cesium iodide waste material and thallium iodide waste material in water to obtain a saturated waste liquid;

[0044] (II) adding activated carbon to the saturated waste liquid, stirring and adsorbing, and then filtering to obtain an iodide solution;

[0045] (III) the iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0046] (IV) The iodide crystal particles are at an absolute pressure of ≤1×10 3 Pa, and the temperature is 300℃-320℃, and the vacuum heating is carried out for 10h-12h to remove the crystal water; then the absolute pressure is ≤3×10 -3 Pa, the temperature is 450℃-470℃, and the first distillation is carried out to obtain thallium iodide with a purity of more than 4N; and the absolute pressure is ≤3×10 -3 The second distillation is carried out under the conditions of 650°C-680°C at 400°C to obtain cesium iodide with a purity of more than 4N.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The method provided by the present invention does not need to add other materials during recycling, and can obtain iodide with a purity of more than 4N, thereby realizing the recycling of waste materials, reducing costs, and reducing the pollution of waste materials to the environment, thereby realizing green circulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A flow chart of a method for recovering iodide waste is provided for the present invention. DETAILED DESCRIPTION

[0050] 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.

[0051] The present invention provides a method for recycling iodide waste, the flow chart of the method is as follows: Figure 1 As shown, the following steps are included:

[0052] S101: The dissolved iodide waste is treated with activated carbon adsorption, and the solid and liquid are separated to obtain an iodide solution.

[0053] S102: The iodide solution is concentrated and crystallized to obtain iodide crystal particles.

[0054] S103: The iodide crystal particles are subjected to vacuum heating and vacuum distillation in sequence to obtain iodide with a purity of 4N or above.

[0055] The method provided by the present invention does not need to add other materials during recycling, and can obtain iodide with a purity of 4N or above (≥99.99wt%), thereby realizing the recycling of waste materials, reducing costs, and reducing the pollution of waste materials to the environment, thereby realizing green circulation.

[0056] In certain embodiments, the iodide waste includes cesium iodide waste or sodium iodide waste.

[0057] In certain embodiments, when the iodide waste includes cesium iodide waste or sodium iodide waste, the temperature of the vacuum heating is 300°C-320°C, for example, it can be 300°C, 305°C, 310°C, 315°C or 320°C, but is not limited to the listed values, and the remaining unlisted values ​​within the numerical range are also applicable.

[0058] In certain embodiments, when the iodide waste includes cesium iodide waste or sodium iodide waste, the vacuum heating time is more than 10 hours, for example, it can be 10 hours, 11 hours, 12 hours, 13 hours, 14 hours or 15 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] In certain embodiments, when the iodide waste includes cesium iodide waste or sodium iodide waste, the absolute pressure of the vacuum heating 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.

[0060] In certain embodiments, when the iodide waste includes cesium iodide waste or sodium iodide waste, the absolute pressure of the vacuum distillation 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.

[0061] In certain embodiments, when the iodide waste is cesium iodide waste, the temperature of the vacuum distillation is 650°C-680°C, for example, 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, when the iodide waste is sodium iodide waste, the temperature of the vacuum distillation 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 other unlisted values ​​within the numerical range are also applicable.

[0063] In certain embodiments, the iodide waste further comprises thallium iodide waste.

[0064] In certain embodiments, when the iodide waste also includes thallium iodide waste, the vacuum heating temperature is 300°C-320°C, for example, it can be 300°C, 305°C, 310°C, 315°C or 320°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0065] In certain embodiments, when the iodide waste also includes thallium iodide waste, the vacuum heating time is more than 10 hours, for example, it can be 10 hours, 10.5 hours, 11 hours, 11.5 hours or 12 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0066] In certain embodiments, when the iodide waste further comprises thallium iodide waste, the absolute pressure of the vacuum heating 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.

[0067] In certain embodiments, when the iodide waste further comprises thallium iodide waste, the absolute pressure of the vacuum distillation 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 certain embodiments, when the iodide waste further comprises thallium iodide waste, the vacuum distillation comprises a first distillation and a second distillation performed sequentially.

[0069] In certain embodiments, the temperature of the first distillation to recover thallium iodide 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 unlisted values ​​within the numerical range are also applicable.

[0070] In certain embodiments, the temperature of the second distillation to recover cesium iodide is 650°C-680°C, for example, 650°C, 655°C, 660°C, 665°C, 670°C, 675°C or 680°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0071] In certain embodiments, the temperature of the second distillation to recover sodium iodide is 700°C-720°C, for example, 700°C, 705°C, 710°C, 715°C or 720°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0072] In certain embodiments, the solution after dissolving the iodide waste material is a saturated aqueous solution.

[0073] 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.

[0074] In certain embodiments, the solid-liquid separation method comprises suction filtration.

[0075] As one of the preferred technical solutions of the method provided by the present invention, the method comprises the following steps:

[0076] (1) dissolving cesium iodide waste in water to obtain saturated cesium iodide waste liquid;

[0077] (2) adding activated carbon to the cesium iodide waste liquid, stirring and adsorbing, and then filtering to obtain a cesium iodide solution;

[0078] (3) The cesium iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0079] (4) The iodide crystal particles are at an absolute pressure of ≤3×10 3 Pa, and the temperature is 300℃-320℃, and the vacuum heating is carried out for more than 10h to remove the crystal water; then the absolute pressure is ≤3×10 -3 Pa, vacuum distillation at a temperature of 650°C-680°C to obtain cesium iodide with a purity of more than 4N.

[0080] As the second preferred technical solution of the method provided by the present invention, the method comprises the following steps:

[0081] (1) sodium iodide waste material is dissolved in water to obtain saturated sodium iodide waste liquid;

[0082] (2) adding activated carbon to the sodium iodide waste liquid, stirring and adsorbing, and then filtering to obtain a sodium iodide solution;

[0083] (3) The sodium iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0084] (4) The iodide crystal particles are at an absolute pressure of ≤3×10 3 Pa, and the temperature is 300℃-320℃, and the vacuum heating is carried out for more than 10h to remove the crystal water; then the absolute pressure is ≤3×10 -3Pa, vacuum distillation at a temperature of 700°C-720°C to obtain sodium iodide with a purity of more than 4N.

[0085] As the third preferred technical solution of the method provided by the present invention, the method comprises the following steps:

[0086] (I) dissolving a combined waste material consisting of sodium iodide waste material and thallium iodide waste material in water to obtain a saturated waste liquid;

[0087] (II) adding activated carbon to the saturated waste liquid, stirring and adsorbing, and then filtering to obtain an iodide solution;

[0088] (III) the iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0089] (IV) The iodide crystal particles are at an absolute pressure of ≤1×10 3 Pa, and the temperature is 300℃-320℃, and the vacuum heating is carried out for 10h-12h to remove the crystal water; then the absolute pressure is ≤3×10 -3 Pa, the temperature is 450℃-470℃, and the first distillation is carried out to obtain thallium iodide with a purity of more than 4N; and the absolute pressure is ≤3×10 -3 Pa, and a second distillation at a temperature of 700°C-720°C to obtain sodium iodide with a purity of more than 4N.

[0090] As a fourth preferred technical solution of the method provided by the present invention, the method comprises the following steps:

[0091] (I) dissolving a combined waste material consisting of cesium iodide waste material and thallium iodide waste material in water to obtain a saturated waste liquid;

[0092] (II) adding activated carbon to the saturated waste liquid, stirring and adsorbing, and then filtering to obtain an iodide solution;

[0093] (III) the iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0094] (IV) The iodide crystal particles are at an absolute pressure of ≤1×10 3 Pa, and the temperature is 300℃-320℃, and the vacuum heating is carried out for 10h-12h to remove the crystal water; then the absolute pressure is ≤3×10 -3 Pa, the temperature is 450℃-470℃, and the first distillation is carried out to obtain thallium iodide with a purity of more than 4N; and the absolute pressure is ≤3×10 -3 The second distillation is carried out under the conditions of 650°C-680°C at 400°C to obtain cesium iodide with a purity of more than 4N.

[0095] 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.

[0096] Test Example 1

[0097] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0098] (1) dissolving cesium iodide waste (cesium iodide purity is 95 wt%) in water to obtain saturated cesium iodide waste liquid;

[0099] (2) adding activated carbon to the cesium iodide waste liquid, stirring and adsorbing, and then filtering with a Buchner funnel to obtain a cesium iodide solution;

[0100] (3) The cesium iodide solution is concentrated and crystallized to obtain iodide crystal particles containing crystal water;

[0101] (4) The iodide crystal particles are at an absolute pressure of 1×10 3 Pa and 310 °C under vacuum heating for 10 h to remove the crystal water; then at an absolute pressure of 3 × 10 -3 Cesium iodide was obtained by vacuum distillation at 370°C and 660°C.

[0102] Test Example 2

[0103] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0104] (1) The same cesium iodide waste material as in Experimental Example 1 was dissolved in water to obtain a saturated cesium iodide waste liquid;

[0105] (2) adding activated carbon to the cesium iodide waste liquid, stirring and adsorbing, and then filtering with a Buchner funnel to obtain a cesium iodide solution;

[0106] (3) The cesium iodide solution is concentrated and crystallized to obtain iodide crystal particles containing crystal water;

[0107] (4) The iodide crystal particles are at an absolute pressure of 1×10 3 Pa and 300 °C under vacuum heating for 10 h to remove the crystal water; then at an absolute pressure of 3 × 10 -3 Cesium iodide was obtained by vacuum distillation at 650°C and 1.5°C.

[0108] Test Example 3

[0109] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0110] (1) The same cesium iodide waste material as in Experimental Example 1 was dissolved in water to obtain a saturated cesium iodide waste liquid;

[0111] (2) adding activated carbon to the cesium iodide waste liquid, stirring and adsorbing, and then filtering with a Buchner funnel to obtain a cesium iodide solution;

[0112] (3) The cesium iodide solution is concentrated and crystallized to obtain iodide crystal particles containing crystal water;

[0113] (4) The iodide crystal particles are at an absolute pressure of 1×10 3 Pa and 320 °C under vacuum heating for 10 h to remove the crystal water; then at an absolute pressure of 3 × 10 -3 Cesium iodide was obtained by vacuum distillation at 680°C and 1.5°C.

[0114] Test Example 4

[0115] This test example provides a method for recovering iodide waste, which is the same as Example 1 except that the vacuum distillation temperature is 640°C.

[0116] Test Example 5

[0117] This test example provides a method for recovering iodide waste, which is the same as Example 1 except that the vacuum distillation temperature is 690°C.

[0118] Test Example 6

[0119] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0120] (1) The same cesium iodide waste material as in Experimental Example 1 was dissolved in water to obtain a saturated cesium iodide waste liquid;

[0121] (2) adding activated carbon to the cesium iodide waste liquid, stirring and adsorbing, and then filtering with a Buchner funnel to obtain a cesium iodide solution;

[0122] (3) The cesium iodide solution is concentrated and crystallized to obtain iodide crystal particles containing crystal water;

[0123] (4) The iodide crystal particles are at an absolute pressure of 3×10 -3 Cesium iodide was obtained by vacuum distillation at 370°C and 660°C.

[0124] Test Example 7

[0125] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0126] (1) The same cesium iodide waste material as in Experimental Example 1 was dissolved in water to obtain a saturated cesium iodide waste liquid;

[0127] (2) adding activated carbon to the cesium iodide waste liquid, stirring and adsorbing, and then filtering with a Buchner funnel to obtain a cesium iodide solution;

[0128] (3) The cesium iodide solution is concentrated and crystallized to obtain iodide crystal particles containing crystal water;

[0129] (4) The iodide crystal particles are at an absolute pressure of 3×10 3 Pa and heated in vacuum at 310 °C for 10 h to remove crystal water and obtain cesium iodide.

[0130] The purity of the cesium iodide obtained in Experimental Examples 1 to 7, and the recovery rate of cesium iodide are shown in Table 1.

[0131] Table 1

[0132] Purity of cesium iodide (wt%) Cesium iodide recovery rate (%) Test Example 1 99.99 95 Test Example 2 99.99 94 Test Example 3 99.99 96 Test Example 4 99.99 85 Test Example 5 99.99 96 Test Example 6 99.99 65 Test Example 7 99 96

[0133] Test Example 8

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

[0135] (1) dissolving sodium iodide waste (sodium iodide purity is 94wt%) in water to obtain saturated sodium iodide waste liquid;

[0136] (2) adding activated carbon to the sodium iodide waste liquid, stirring and adsorbing, and then filtering with a Buchner funnel to obtain a sodium iodide solution;

[0137] (3) The sodium iodide solution is concentrated and crystallized to obtain iodide crystal particles containing crystal water;

[0138] (4) The iodide crystal particles are at an absolute pressure of 1×10 3 Pa and 310 °C under vacuum heating for 10 h to remove the crystal water; then at an absolute pressure of 3 × 10 -3 Pa and vacuum distillation at 710°C to obtain sodium iodide.

[0139] Test Example 9

[0140] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0141] (1) The same sodium iodide waste material as in Experimental Example 8 was dissolved in water to obtain a saturated sodium iodide waste liquid;

[0142] (2) adding activated carbon to the sodium iodide waste liquid, stirring and adsorbing, and then filtering with a Buchner funnel to obtain a sodium iodide solution;

[0143] (3) The sodium iodide solution is concentrated and crystallized to obtain iodide crystal particles containing crystal water;

[0144] (4) The iodide crystal particles are at an absolute pressure of 1×10 3 Pa and 300 °C under vacuum heating for 10 h to remove the crystal water; then at an absolute pressure of 3 × 10 -3 Pa, vacuum distillation at 700 ° C to obtain sodium iodide.

[0145] Test Example 10

[0146] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0147] (1) The same sodium iodide waste material as in Test Example 8 was dissolved in water to obtain a saturated sodium iodide waste liquid;

[0148] (2) adding activated carbon to the sodium iodide waste liquid, stirring and adsorbing, and then filtering with a Buchner funnel to obtain a sodium iodide solution;

[0149] (3) The sodium iodide solution is concentrated and crystallized to obtain iodide crystal particles containing crystal water;

[0150] (4) The iodide crystal particles are at an absolute pressure of 1×10 3 Pa and 320 °C under vacuum heating for 10 h to remove the crystal water; then at an absolute pressure of 3 × 10 -3 Pa and vacuum distillation at 720°C to obtain sodium iodide.

[0151] Test Example 11

[0152] This test example provides a method for recovering iodide waste, which is the same as Example 1 except that the vacuum distillation temperature is 690°C.

[0153] Test Example 12

[0154] This test example provides a method for recovering iodide waste, which is the same as Example 1 except that the vacuum distillation temperature is 730°C.

[0155] Test Example 13

[0156] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0157] (1) The same sodium iodide waste material as in Test Example 8 was dissolved in water to obtain a saturated sodium iodide waste liquid;

[0158] (2) adding activated carbon to the sodium iodide waste liquid, stirring and adsorbing, and then filtering with a Buchner funnel to obtain a sodium iodide solution;

[0159] (3) The sodium iodide solution is concentrated and crystallized to obtain iodide crystal particles containing crystal water;

[0160] (4) The iodide crystal particles are at an absolute pressure of 3×10 -3 Pa and vacuum distillation at 710°C to obtain sodium iodide.

[0161] Test Example 14

[0162] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0163] (1) The same sodium iodide waste material as in Test Example 8 was dissolved in water to obtain a saturated sodium iodide waste liquid;

[0164] (2) adding activated carbon to the sodium iodide waste liquid, stirring and adsorbing, and then filtering with a Buchner funnel to obtain a sodium iodide solution;

[0165] (3) The sodium iodide solution is concentrated and crystallized to obtain iodide crystal particles containing crystal water;

[0166] (4) The iodide crystal particles are at an absolute pressure of 3×10 3 Pa, and vacuum heating at 310 ° C for 10 h to remove crystal water and obtain sodium iodide.

[0167] The purity of the sodium iodide obtained in Experimental Examples 8 to 14, and the recovery rate of sodium iodide are shown in Table 2.

[0168] Table 2

[0169] Sodium iodide purity (wt%) Sodium iodide recovery rate (%) Test Example 8 99.99 95 Test Example 9 99.99 94 Test Example 10 99.99 96 Test Example 11 99.99 84 Test Example 12 99.99 96 Test Example 13 99.99 65 Test Example 14 99 96

[0170] Test Example 15

[0171] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0172] (I) dissolving iodide waste composed of sodium iodide waste and thallium iodide waste (sodium iodide content is 82.9wt%, thallium iodide content is 0.42wt%) in water to obtain saturated waste liquid;

[0173] (II) adding activated carbon to the saturated waste liquid, stirring and adsorbing, and then filtering to obtain an iodide solution;

[0174] (III) the iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0175] (IV) The iodide crystal particles are at an absolute pressure of 3×10 3 Pa and 310 °C for 11 h in vacuum to remove the crystal water; then -3 Pa and a temperature of 460°C to obtain thallium iodide; then the absolute pressure was 3×10 -3 Pa, and a second distillation at a temperature of 710°C to obtain sodium iodide.

[0176] Test Example 16

[0177] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0178] (I) The same iodide waste as in Test Example 15 was dissolved in water to obtain a saturated waste liquid;

[0179] (II) adding activated carbon to the saturated waste liquid, stirring and adsorbing, and then filtering to obtain an iodide solution;

[0180] (III) the iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0181] (IV) The iodide crystal particles are at an absolute pressure of 3×10 3 Pa and 300 °C under vacuum heating for 12 h to remove the crystal water; then at an absolute pressure of 3 × 10 -3 Pa and a temperature of 450 ° C to obtain thallium iodide; then the absolute pressure was 3 × 10 -3 Pa, and a second distillation at a temperature of 700°C to obtain sodium iodide.

[0182] Test Example 17

[0183] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0184] (I) The same iodide waste as in Test Example 15 was dissolved in water to obtain a saturated waste liquid;

[0185] (II) adding activated carbon to the saturated waste liquid, stirring and adsorbing, and then filtering to obtain an iodide solution;

[0186] (III) the iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0187] (IV) The iodide crystal particles are at an absolute pressure of 3×10 3 Pa and 320 °C under vacuum heating for 10 h to remove the crystal water; then at an absolute pressure of 3 × 10 -3 Pa and a temperature of 470 ° C to obtain thallium iodide; then the absolute pressure was 3 × 10 -3 Pa, and a second distillation at a temperature of 720°C to obtain sodium iodide.

[0188] Test Example 18

[0189] This test example provides a method for recovering iodide waste, which is the same as Test Example 15 except that the temperature of the first distillation is 440°C.

[0190] Test Example 19

[0191] This test example provides a method for recovering iodide waste, which is the same as Test Example 15 except that the temperature of the first distillation is 480°C.

[0192] Test Example 20

[0193] This test example provides a method for recovering iodide waste, which is the same as Test Example 15 except that the temperature of the second distillation is 690°C.

[0194] Test Example 21

[0195] This test example provides a method for recovering iodide waste, which is the same as Test Example 15 except that the temperature of the second distillation is 730°C.

[0196] Test Example 22

[0197] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0198] (I) The same iodide waste as in Test Example 15 was dissolved in water to obtain a saturated waste liquid;

[0199] (II) adding activated carbon to the saturated waste liquid, stirring and adsorbing, and then filtering to obtain an iodide solution;

[0200] (III) the iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0201] (IV) The iodide crystal particles are at an absolute pressure of 3×10 -3 Pa and a temperature of 460°C to obtain thallium iodide; then the absolute pressure was 3×10-3 Pa, and a second distillation at a temperature of 710°C to obtain sodium iodide.

[0202] The purity of sodium iodide and thallium iodide obtained in Experimental Examples 15 to 22, as well as the recovery rates of sodium iodide and thallium iodide are shown in Table 3.

[0203] Table 3

[0204]

[0205] Test Example 23

[0206] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0207] (I) dissolving iodide waste composed of cesium iodide waste and thallium iodide waste (cesium iodide content is 82.9wt% and thallium iodide content is 0.42wt%) in water to obtain saturated waste liquid;

[0208] (II) adding activated carbon to the saturated waste liquid, stirring and adsorbing, and then filtering to obtain an iodide solution;

[0209] (III) the iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0210] (IV) The iodide crystal particles are at an absolute pressure of 3×10 3 Pa and 310 °C for 11 h in vacuum to remove the crystal water; then -3 Pa and a temperature of 460°C to obtain thallium iodide; then the absolute pressure was 3×10 -3 The second distillation was carried out under the conditions of 1.5 ℃ and 4.5 ℃ and 660 ℃ to obtain cesium iodide.

[0211] Test Example 24

[0212] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0213] (I) The same iodide waste as in Test Example 23 was dissolved in water to obtain a saturated waste liquid;

[0214] (II) adding activated carbon to the saturated waste liquid, stirring and adsorbing, and then filtering to obtain an iodide solution;

[0215] (III) the iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0216] (IV) The iodide crystal particles are at an absolute pressure of 3×10 3Pa and 300 °C under vacuum heating for 12 h to remove the crystal water; then at an absolute pressure of 3 × 10 -3 Pa and a temperature of 450 ° C to obtain thallium iodide; then the absolute pressure was 3 × 10 -3 The second distillation was carried out under the conditions of 1.5 ℃ and 4.5 ℃ and 650 ℃ to obtain cesium iodide.

[0217] Test Example 25

[0218] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0219] (I) The same iodide waste as in Test Example 23 was dissolved in water to obtain a saturated waste liquid;

[0220] (II) adding activated carbon to the saturated waste liquid, stirring and adsorbing, and then filtering to obtain an iodide solution;

[0221] (III) the iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0222] (IV) The iodide crystal particles are at an absolute pressure of 3×10 3 Pa and 320 °C under vacuum heating for 10 h to remove the crystal water; then at an absolute pressure of 3 × 10 -3 Pa and a temperature of 470 ° C to obtain thallium iodide; then the absolute pressure was 3 × 10 -3 The second distillation was carried out under the conditions of 1.5 ℃ and 4.5 ℃ and 680 ℃ to obtain cesium iodide.

[0223] Test Example 26

[0224] This test example provides a method for recovering iodide waste, which is the same as Test Example 23 except that the temperature of the second distillation is 640°C.

[0225] Test Example 27

[0226] This test example provides a method for recovering iodide waste, which is the same as Test Example 23 except that the temperature of the second distillation is 690°C.

[0227] Test Example 28

[0228] This test example provides a method for recovering iodide waste, the method comprising the following steps:

[0229] (I) The same iodide waste as in Test Example 23 was dissolved in water to obtain a saturated waste liquid;

[0230] (II) adding activated carbon to the saturated waste liquid, stirring and adsorbing, and then filtering to obtain an iodide solution;

[0231] (III) the iodide solution is concentrated and crystallized to obtain iodide crystal particles;

[0232] (IV) The iodide crystal particles are at an absolute pressure of 3×10 -3 Pa and a temperature of 460°C to obtain thallium iodide; then the absolute pressure was 3×10 -3 The second distillation was carried out under the conditions of 1.5 ℃ and 4.5 ℃ and 660 ℃ to obtain cesium iodide.

[0233] The purity of the cesium iodide and thallium iodide obtained in Experimental Examples 23 to 28, as well as the recovery rates of the cesium iodide and thallium iodide are shown in Table 4.

[0234] Table 4

[0235]

[0236]

[0237] In summary, the method provided by the present invention does not require the addition of other materials during recycling, and can obtain iodide with a purity of more than 4N, thereby realizing the recycling of waste materials, reducing costs, and reducing the pollution of waste materials to the environment, thereby realizing a green cycle.

[0238] 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 recycling iodide waste, characterized in that: The method comprises the following steps: The dissolved iodide waste is subjected to activated carbon adsorption treatment, solid-liquid separation, and an iodide solution is obtained; the iodide solution is concentrated and crystallized to obtain iodide crystal particles; The iodide crystal particles are sequentially subjected to vacuum heating and vacuum distillation to obtain iodide with a purity of more than 4N.

2. The method according to claim 1, characterized in that The iodide waste includes cesium iodide waste or sodium iodide waste.

3. The method according to claim 2, characterized in that The temperature of the vacuum heating is 300°C-320°C; And / or, the vacuum heating time is more than 10 hours; And / or, the absolute pressure of the vacuum heating is ≤3×10 3 Pa.

4. The method according to claim 2, characterized in that: The absolute pressure of the vacuum distillation is ≤3×10 -3 Pa; And / or, when the iodide waste is cesium iodide waste, the temperature of the vacuum distillation is 650° C.-680° C.; And / or, when the iodide waste material is sodium iodide waste material, the temperature of the vacuum distillation is 700°C-720°C.

5. The method according to claim 2, characterized in that: The iodide waste also includes thallium iodide waste.

6. The method according to claim 5, characterized in that The temperature of the vacuum heating is 300°C-320°C; And / or, the vacuum heating time is more than 10 hours; And / or, the absolute pressure of the vacuum heating is ≤3×10 3 Pa.

7. The method according to claim 5, characterized in that The absolute pressure of the vacuum distillation is ≤3×10 -3 Pa; And / or, the vacuum distillation includes a first distillation and a second distillation performed sequentially; The first distillation recovers thallium iodide; the second distillation recovers cesium iodide or sodium iodide; And / or, the temperature of the first distillation to recover thallium iodide is 450° C.-470° C.; And / or, the temperature of the second distillation to recover cesium iodide is 650° C.-680° C.; And / or, the temperature of the second distillation to recover sodium iodide is 700°C-720°C.

8. The method according to claim 1, characterized in that The solution after the iodide waste material is dissolved is a saturated aqueous solution.

9. 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.

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

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