Method for recovering rare earth elements in lutetium yttrium silicate
阅读说明：本技术 一种回收硅酸钇镥中稀土元素的方法 (Method for recovering rare earth elements in lutetium yttrium silicate ) 是由 潘务霞 张亮玖 周慧荣 雷利利 庄辉 蓝灵江 马宗云 欧小萍 覃世富 俞志春 李 于 2020-12-31 设计创作，主要内容包括：本发明公开了一种回收硅酸钇镥中稀土元素的方法,其取硅酸钇镥置于反应容器中,加入硝酸和氟化氢,所述硅酸钇镥的质量与硝酸的体积比为1g:10ml,所述硝酸与氟化氢的体积比为2:3,然后在温度为100～300℃的条件下加热溶解至近干,接着加入高氯酸继续加热冒烟至溶液体积减少至原体积的1/10,再自然冷却降温至无白烟冒出后得到溶液A,所述高氯酸的加入体积与硝酸加入体积的比为2:1；向溶液A中加入盐酸,并且小火加热溶解至清亮,然后自然冷却降温至60～80℃后进行过过滤,分离除去滤渣得到含有钇镥的氯化钇镥料液。本发明有效解决了现有回收中存在的回收效率低、能耗高的问题。(The invention discloses a method for recovering rare earth elements in lutetium yttrium silicate, which comprises the steps of putting lutetium yttrium silicate into a reaction container, adding nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of lutetium yttrium silicate to nitric acid is 1g to 10ml, the volume ratio of nitric acid to hydrogen fluoride is 2 to 3, heating and dissolving at the temperature of 100-300 ℃ until the lutetium yttrium silicate is nearly dry, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling until no white smoke is emitted to obtain a solution A, and the ratio of the volume of perchloric acid to the volume of nitric acid is 2 to 1; and adding hydrochloric acid into the solution A, heating with soft fire to dissolve the hydrochloric acid until the solution A is clear, naturally cooling to 60-80 ℃, filtering, and separating to remove filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium. The invention effectively solves the problems of low recovery efficiency and high energy consumption in the existing recovery.)
1. A method for recovering rare earth elements in lutetium yttrium silicate is characterized by comprising the following steps: the method comprises the following steps:
(1) placing yttrium lutetium silicate in a reaction container, adding nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of the yttrium lutetium silicate to the nitric acid is 1g:10ml, the volume ratio of the nitric acid to the hydrogen fluoride is 2:3, heating and dissolving the yttrium lutetium silicate to be nearly dry at the temperature of 100-300 ℃, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling to obtain a solution A after no white smoke is emitted, and the ratio of the volume of the added perchloric acid to the volume of the added nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid into the solution A obtained in the step (1), heating and dissolving the solution A by small fire until the solution A is clear, naturally cooling the solution A to 60-80 ℃, filtering the solution A, and separating and removing filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
2. The method of claim 1 for recovering rare earth elements from lutetium yttrium silicate, wherein: the mass fraction of the nitric acid is 50%.
3. The method of claim 1 for recovering rare earth elements from lutetium yttrium silicate, wherein: the molar concentration of the hydrochloric acid is 6 mol/L.
4. The method of claim 1 for recovering rare earth elements from lutetium yttrium silicate, wherein: the heating and dissolving to be nearly dry in the step (1) is to evaporate the volume of the solution to 1/10-1/20 of the original volume.
5. The method of claim 1 for recovering rare earth elements from lutetium yttrium silicate, wherein: in the step (2), the solution A is heated to 100-400 ℃ with small fire for dissolution.
Technical Field
The invention belongs to the technical field of rare earth element resource recycling, and particularly relates to a method for recycling rare earth elements in lutetium yttrium silicate.
Background
The yttrium lutetium silicate is a high-performance scintillation crystal of large nuclear medical equipment and other high-end equipment which are the highest end and the most advanced in the world and have a large application range at present, and is an important raw material in the fields of various radioactive detections, medical equipment, aviation equipment and the like. For example, yttrium lutetium silicate scintillation crystal (LYSO) attracts great attention in the international scintillation crystal world due to the characteristics of high light output, fast luminescence attenuation, high effective atomic number, high density and the like, has stable physicochemical properties, is not deliquescent, has high detection efficiency on gamma rays, is considered as an inorganic scintillation crystal material with the best comprehensive performance, and is an ideal scintillation crystal for SPECT and PET for replacing NaI (Tl) and BGO in the future. In addition, LYSO crystals have wide applications in the fields of high-energy physics, nuclear physics, oil well drilling, safety inspection, environmental inspection, and the like. But at least 20 percent of cutting scraps are generated in the production or application process of the lutetium yttrium silicate crystal, and in order to realize the purposes of efficient comprehensive utilization of rare earth resources and environment coordinated development, valuable rare earth elements are extracted and separated from lutetium yttrium silicate waste, so that the lutetium yttrium silicate crystal has economic and environmental benefits.
At present, researches on comprehensive recovery of rare earth elements from yttrium lutetium silicate waste are few, and the researches mainly collect the recovery of valuable rare earth elements in the yttrium lutetium silicate by roasting flaky alkali and the yttrium lutetium silicate at high temperature and leaching in cold water.
Disclosure of Invention
Aiming at the defects, the invention discloses a method for recovering rare earth elements in lutetium yttrium silicate, which solves the problems of low recovery efficiency and high energy consumption in the existing recovery.
The invention is realized by adopting the following technical scheme:
a method for recovering rare earth elements in lutetium yttrium silicate comprises the following steps:
(1) placing yttrium lutetium silicate in a reaction container, adding nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of the yttrium lutetium silicate to the nitric acid is 1g:10ml, the volume ratio of the nitric acid to the hydrogen fluoride is 2:3, heating and dissolving the yttrium lutetium silicate to be nearly dry at the temperature of 100-300 ℃, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling to obtain a solution A after no white smoke is emitted, and the ratio of the volume of the added perchloric acid to the volume of the added nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid into the solution A obtained in the step (1), heating and dissolving the solution A by small fire until the solution A is clear, naturally cooling the solution A to 60-80 ℃, filtering the solution A, and separating and removing filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
Under the condition of low-temperature heating, yttrium lutetium silicate reacts with nitric acid and hydrofluoric acid to generate yttrium lutetium fluoride, and the dosage ratio of nitric acid, hydrogen fluoride and yttrium lutetium silicate is controlled to ensure that yttrium lutetium rare earth in the yttrium lutetium silicate can be fully converted into rare earth fluoride; and then quantitatively adding perchloric acid for smoking to remove silicon impurities, adding hydrochloric acid into the yttrium lutetium after impurity removal, slowly heating for dissolving, converting into lutetium yttrium chloride feed liquid, cooling to 60-80 ℃, filtering for removing residues, easily precipitating rare earth chloride at a low temperature to cause loss, and filtering to obtain the qualified raw material for the next process. The main equation is as follows:
LuY（SiO3）1.5+3HF=LuYF3+1.5H2SiO3；
LuYF3+3HCl=LuYCl3+3HF。
further, the mass fraction of the nitric acid is 50%.
Further, the molar concentration of the hydrochloric acid is 6 mol/L.
Further, the heating and dissolving to be nearly dry is to evaporate the volume of the solution to 1/10-1/20 of the original volume. Thus, the lutetium yttrium silicate can be fully converted into rare earth fluoride.
Further, in the step (2), the solution A is heated to 100-400 ℃ with small fire for dissolution. The method of slowly heating and raising the temperature controls the dissolving temperature to be 100-400 ℃, promotes the dissolution of the rare earth chloride, is beneficial to the subsequent separation and deslagging, and reduces the loss of yttrium lutetium element.
Compared with the prior art, the technical scheme has the following beneficial effects:
1. the method of the invention adopts the reaction of nitric acid, hydrofluoric acid and lutetium yttrium silicate under the condition of low-temperature slow heating, uses perchloric acid to smoke and remove silicon, and adopts the conversion mode of hydrochloric acid to recover valuable rare earth elements in lutetium yttrium silicate.
2. The recovery rate of the yttrium lutetium rare earth obtained by the method can reach more than 95 percent, and the method has the advantages of simple process, strong controllability, short process time, no need of high-temperature operation, reduced energy consumption and suitability for large-scale and industrial production of the recovery of the yttrium lutetium rare earth.
Detailed Description
The invention is further illustrated by the following examples, which are not to be construed as limiting the invention thereto. The specific experimental conditions and methods not indicated in the following examples are generally conventional means well known to those skilled in the art.
Example 1:
a method for recovering rare earth elements in lutetium yttrium silicate comprises the following steps:
(1) placing lutetium yttrium silicate in a reaction container, adding 50% by mass of nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of lutetium yttrium silicate to nitric acid is 1g:10ml, the volume ratio of nitric acid to hydrogen fluoride is 2:3, heating and dissolving at 200 ℃ until the lutetium yttrium silicate is nearly dry, evaporating the volume of the solution to 1/20 of the original volume, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling until no white smoke is emitted to obtain a solution A, and the ratio of the volume of perchloric acid to the volume of nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid with the molar concentration of 6mol/L into the solution A obtained in the step (1), heating the solution A with soft fire to 200 ℃ for dissolving until the solution is clear, naturally cooling the solution to 70 ℃, filtering the solution, and separating and removing filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
Example 2:
a method for recovering rare earth elements in lutetium yttrium silicate comprises the following steps:
(1) placing lutetium yttrium silicate in a reaction container, adding 50% by mass of nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of lutetium yttrium silicate to nitric acid is 1g:10ml, the volume ratio of nitric acid to hydrogen fluoride is 2:3, heating and dissolving at the temperature of 150 ℃ until the lutetium yttrium silicate is nearly dry, evaporating the volume of the solution to 1/10 of the original volume, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling until no white smoke is emitted to obtain a solution A, and the ratio of the volume of perchloric acid to the volume of nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid with the molar concentration of 6mol/L into the solution A obtained in the step (1), heating to 100 ℃ with soft fire, dissolving to be clear, naturally cooling to 80 ℃, filtering, and separating to remove filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
Example 3:
a method for recovering rare earth elements in lutetium yttrium silicate comprises the following steps:
(1) placing lutetium yttrium silicate in a reaction container, adding 50% by mass of nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of lutetium yttrium silicate to nitric acid is 1g:10ml, the volume ratio of nitric acid to hydrogen fluoride is 2:3, heating and dissolving at 100 ℃ until the lutetium yttrium silicate is nearly dry, evaporating the volume of the solution to 1/15 of the original volume, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling until no white smoke is emitted to obtain a solution A, and the ratio of the volume of perchloric acid to the volume of nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid with the molar concentration of 6mol/L into the solution A obtained in the step (1), heating to 150 ℃ with soft fire, dissolving until the solution is clear, naturally cooling to 60 ℃, filtering, and separating and removing filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
Example 4:
a method for recovering rare earth elements in lutetium yttrium silicate comprises the following steps:
(1) placing lutetium yttrium silicate in a reaction container, adding 50% by mass of nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of lutetium yttrium silicate to nitric acid is 1g:10ml, the volume ratio of nitric acid to hydrogen fluoride is 2:3, heating and dissolving at 220 ℃ until the lutetium yttrium silicate is nearly dry, evaporating the volume of the solution to 1/20 of the original volume, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling until no white smoke is emitted to obtain a solution A, and the ratio of the volume of perchloric acid to the volume of nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid with the molar concentration of 6mol/L into the solution A obtained in the step (1), heating to 250 ℃ with soft fire, dissolving to be clear, naturally cooling to 70 ℃, filtering, and separating to remove filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
Example 5:
a method for recovering rare earth elements in lutetium yttrium silicate comprises the following steps:
(1) placing lutetium yttrium silicate in a reaction container, adding 50% by mass of nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of lutetium yttrium silicate to nitric acid is 1g:10ml, the volume ratio of nitric acid to hydrogen fluoride is 2:3, heating and dissolving at 300 ℃ until the lutetium yttrium silicate is nearly dry, evaporating the volume of the solution to 1/10 of the original volume, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling until no white smoke is emitted to obtain a solution A, and the ratio of the volume of perchloric acid to the volume of nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid with the molar concentration of 6mol/L into the solution A obtained in the step (1), heating to 400 ℃ with soft fire, dissolving to be clear, naturally cooling to 65 ℃, filtering, and separating to remove filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
Example 6:
a method for recovering rare earth elements in lutetium yttrium silicate comprises the following steps:
(1) placing lutetium yttrium silicate in a reaction container, adding 50% by mass of nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of lutetium yttrium silicate to nitric acid is 1g:10ml, the volume ratio of nitric acid to hydrogen fluoride is 2:3, heating and dissolving at 250 ℃ until the lutetium yttrium silicate is nearly dry, evaporating the volume of the solution to 1/18 of the original volume, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling until no white smoke is emitted to obtain a solution A, and the ratio of the volume of perchloric acid to the volume of nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid with the molar concentration of 6mol/L into the solution A obtained in the step (1), heating to 300 ℃ with soft fire, dissolving until the solution is clear, naturally cooling to 75 ℃, filtering, and separating and removing filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
Comparative example 1:
reacting caustic soda flakes with 100-mesh yttrium lutetium silicate at a constant temperature of 600 ℃ for 6 hours, soaking in cold water for several days, filtering, washing with water until the pH of a leaching solution is 7, and dissolving with 6mol/L of filter residue hydrochloric acid to obtain a yttrium lutetium chloride solution.
Comparative example 2:
a method for recovering rare earth elements in lutetium yttrium silicate comprises the following steps:
(1) placing lutetium yttrium silicate in a reaction container, adding 50% by mass of nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of lutetium yttrium silicate to nitric acid is 1g:10ml, the volume ratio of nitric acid to hydrogen fluoride is 2:3, heating and dissolving at 200 ℃ until the lutetium yttrium silicate is nearly dry, evaporating the volume of the solution to 1/5 of the original volume, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling until no white smoke is emitted to obtain a solution A, and the ratio of the volume of perchloric acid to the volume of nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid with the molar concentration of 6mol/L into the solution A obtained in the step (1), heating the solution A with soft fire to 200 ℃ for dissolving until the solution is clear, naturally cooling the solution to 70 ℃, filtering the solution, and separating and removing filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
Comparative example 3:
a method for recovering rare earth elements in lutetium yttrium silicate comprises the following steps:
(1) placing lutetium yttrium silicate in a reaction container, adding 50% by mass of nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of lutetium yttrium silicate to nitric acid is 1g:10ml, the volume ratio of nitric acid to hydrogen fluoride is 2:3, heating and dissolving at 200 ℃ until the lutetium yttrium silicate is nearly dry, evaporating the volume of the solution to 1/2 of the original volume, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling until no white smoke is emitted to obtain a solution A, and the ratio of the volume of perchloric acid to the volume of nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid with the molar concentration of 6mol/L into the solution A obtained in the step (1), heating the solution A with soft fire to 200 ℃ for dissolving until the solution is clear, naturally cooling the solution to 70 ℃, filtering the solution, and separating and removing filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
Comparative example 4:
a method for recovering rare earth elements in lutetium yttrium silicate comprises the following steps:
(1) placing lutetium yttrium silicate in a reaction container, adding 50% by mass of nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of lutetium yttrium silicate to nitric acid is 1g:10ml, the volume ratio of nitric acid to hydrogen fluoride is 2:3, heating and dissolving at 200 ℃ until the lutetium yttrium silicate is nearly dry, evaporating the volume of the solution to 1/30 of the original volume, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling until no white smoke is emitted to obtain a solution A, and the ratio of the volume of perchloric acid to the volume of nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid with the molar concentration of 6mol/L into the solution A obtained in the step (1), heating the solution A with soft fire to 200 ℃ for dissolving until the solution is clear, naturally cooling the solution to 25 ℃, filtering the solution, and separating and removing filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
Comparative example 5:
a method for recovering rare earth elements in lutetium yttrium silicate comprises the following steps:
(1) placing lutetium yttrium silicate in a reaction container, adding 50% by mass of nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of lutetium yttrium silicate to nitric acid is 1g:10ml, the volume ratio of nitric acid to hydrogen fluoride is 2:3, heating and dissolving at 200 ℃ until the lutetium yttrium silicate is nearly dry, evaporating the volume of the solution to 1/20 of the original volume, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling until no white smoke is emitted to obtain a solution A, and the ratio of the volume of perchloric acid to the volume of nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid with the molar concentration of 6mol/L into the solution A obtained in the step (1), heating the solution A with soft fire to 200 ℃ for dissolving until the solution is clear, naturally cooling the solution to 50 ℃, filtering the solution, and separating and removing filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
Comparative example 6:
a method for recovering rare earth elements in lutetium yttrium silicate comprises the following steps:
(1) placing lutetium yttrium silicate in a reaction container, adding 50% by mass of nitric acid and hydrogen fluoride, wherein the volume ratio of the mass of lutetium yttrium silicate to nitric acid is 1g:10ml, the volume ratio of nitric acid to hydrogen fluoride is 2:3, heating and dissolving at 200 ℃ until the lutetium yttrium silicate is nearly dry, evaporating the volume of the solution to 1/20 of the original volume, adding perchloric acid, continuously heating and smoking until the volume of the solution is reduced to 1/10 of the original volume, naturally cooling until no white smoke is emitted to obtain a solution A, and the ratio of the volume of perchloric acid to the volume of nitric acid is 2: 1;
(2) and (2) adding hydrochloric acid with the molar concentration of 6mol/L into the solution A obtained in the step (1), heating the solution A with soft fire to 200 ℃ for dissolving until the solution is clear, naturally cooling the solution to 40 ℃, filtering the solution, and separating and removing filter residues to obtain yttrium lutetium chloride feed liquid containing yttrium lutetium.
Experimental example:
the rare earth elements are recovered from the yttrium lutetium silicate crystals by the methods described in examples 1-6 and comparative examples 1-6, and the recovery rate of yttrium lutetium rare earth is shown in table 1.
TABLE 1 recovery of yttrium lutetium rare earth
Recovery rate of yttrium lutetium rare earth (%)
Example 1
96.45
Example 2
96.02
Example 3
96.11
Example 4
96.33
Example 5
95.23
Example 6
95.76
Comparative example 1
88.70
Comparative example 2
91.24
Comparative example 3
90.89
Comparative example 4
89.77
Comparative example 5
90.25
Comparative example 6
90.63
From the data, the recovery rate of yttrium lutetium rare earth is more than 95% when the method is used for recovering yttrium lutetium rare earth, but the recovery rate of yttrium lutetium rare earth obtained by the method of reacting the caustic soda flake with the yttrium lutetium silicate in the comparative example 1 is only 88.70%, and the method is not soaked in cold water, so that the operation time is obviously shortened compared with that in the comparative example 1, compared with the prior art, the method has obvious progress, and meanwhile, compared with comparative examples 2-4, according to the method in the invention, when the yttrium lutetium silicate solution added with nitric acid and hydrogen fluoride is heated and dissolved to 1/5, 1/2 or 1/30 of the original volume, the yttrium lutetium rare earth cannot be completely converted into the rare earth fluoride, so that the recovery rate of the yttrium lutetium rare earth is about 91%, and compared with the prior art, the method is not large, and only the process operation time is saved; comparative examples 4-6 according to the method of the present invention, the difference is that the solution dissolved by adding hydrochloric acid is cooled to below 50 ℃ and filtered, so that rare earth chloride is partially precipitated at a too low temperature to cause loss, and the recovery rate of the obtained yttrium lutetium rare earth is about 90%, which is not much different from the prior art and only saves the process operation time.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.