CN111252797B - Method for preparing rare earth fluoride particles under acidic conditions and use of carboxylic acids or salts thereof - Google Patents
Method for preparing rare earth fluoride particles under acidic conditions and use of carboxylic acids or salts thereof Download PDFInfo
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Abstract
The invention discloses a method for preparing rare earth fluoride particles under acidic conditions and application of carboxylic acid or salts thereof. The method comprises the following steps: dripping the fluorine-containing acidic solution A and the soluble rare earth salt solution B into the base solution C in a parallel flow manner to react to obtain a mixed solution; wherein, the fluorine-containing acid solution A is an acid solution containing a fluorinating agent; the soluble rare earth salt solution B is an aqueous solution containing soluble rare earth salt; the base solution C is water or an ammonium salt aqueous solution; the fluorine-containing acidic solution A and/or the base solution C contain an acidity-induced crystallization agent which is a carboxylic acid or a salt thereof capable of releasing a free carboxylate radical in an acidic medium. The product obtained by the method has large particle size and high fluorine conversion rate.
Description
Technical Field
The invention relates to a method for preparing rare earth fluoride particles under acidic conditions and application of carboxylic acid or salt thereof.
Background
The rare earth fluoride can be called as rare earth metal fluoride, can be used as an additive of steel, non-ferrous metal alloy and carbon arc rods, can also be used as a raw material for reduction electrolysis of rare earth metal and an electrolyte for molten salt electrolysis, and can also be used as a milky white agent for ceramic glaze, a glass polishing material, a crystal material additive, an organic synthesis catalyst and the like.
The preparation method of the rare earth fluoride comprises a wet process and a dry process. In the dry process, rare earth oxide (or carbonate) and hydrogen fluoride gas (or ammonium bifluoride solid) are heated together to obtain rare earth fluoride. The process has short flow and high production efficiency, but the operation is relatively complex, and high-temperature fluorine-resistant materials are required, so the equipment selection is difficult, and the production cost is high. The wet process includes a precipitation process and a salt conversion process. In the precipitation process, a soluble rare earth salt solution is directly reacted with a fluorinating agent to form a rare earth fluoride precipitate. The rare earth fluoride synthesized by the method has fine and colloidal particles, poor crystal form, high entrainment of water and impurities and poor working condition environment. In the salt conversion process, rare earth salt precursors (rare earth carbonate, rare earth oxalate and rare earth hydroxide) are reacted with hydrofluoric acid (or ammonium bifluoride) to obtain rare earth fluoride particles. The conversion of the precursor to fluoride of this process is not high.
CN1048531A discloses a method for preparing rare earth metal fluoride, which comprises the steps of taking soluble rare earth salt water solution, rare earth oxide, oxalic acid rare earth salt, ammonium rare earth sulfate double salt or slurry of acid carbonic acid rare earth salt as raw material liquid, firstly adding oxalic acid and then hydrofluoric acid, and carrying out solid-liquid separation to obtain the rare earth metal fluoride. The method firstly generates rare earth oxalate, and then hydrofluoric acid is added for fluorination. Therefore, the amount of oxalic acid is large and an excessive amount of hydrofluoric acid is required.
CN1337357A discloses a method for preparing rare earth fluoride, which comprises mixing hydrofluoric acid and ammonia water to obtain a composite fluorinating agent, mixing rare earth feed liquid with the composite fluorinating agent, and carrying out fluorination and precipitation to obtain the rare earth fluoride. In the method, the dosage of hydrofluoric acid is 105-120% of the theoretical dosage of hydrofluoric acid required for precipitating the rare earth. In addition, the method easily produces wastewater containing fluorine.
CN101607733A discloses a method for preparing rare earth fluoride by taking rare earth oxide as a raw material. Mixing rare earth oxide with water, and adding concentrated hydrochloric acid to react to generate a rare earth chloride solution; heating the rare earth chloride solution to 70-90 ℃, adding malonic acid serving as a precipitator, and then preserving heat for 10-30 minutes; adding hydrofluoric acid into the reaction solution, and carrying out fluorination reaction at 70-90 ℃; and washing, settling, filtering and drying the precipitate generated by the reaction to obtain the rare earth fluoride. The above method uses malonic acid as a precipitant, not as an induced crystallization agent. Therefore, although the method can increase the size of the rare earth fluoride particles to some extent, it cannot perform the function of malonic acid induced crystallization because of the way of precipitation followed by fluorination, and the particle size of the rare earth fluoride particles is still small, which is not favorable for filtration. In addition, in the above method, it is necessary to use a slight excess of hydrofluoric acid (the amount of hydrofluoric acid used is 101% to 105% of the theoretical amount thereof), and therefore, fluorine-containing waste water is generated.
CN106978090A discloses a preparation method of rare earth fluoride polishing powder, which comprises the following steps: s1, adding 100g/L of light rare earth acid solution into a reaction kettle, heating and stirring to 75 ℃, and keeping the temperature constant; s2, preparing oxalic acid accounting for 115% of the total weight of the rare earth in the reaction kettle into a saturated solution with the temperature of 45-55 ℃; s3, dropwise adding the oxalic acid saturated solution into the reaction kettle at a speed of 50 drops/min; s4, when the oxalic acid saturated solution is dripped to 1/5 of the total amount, dripping hydrofluoric acid liquid which accounts for 5-10% of the total weight of the rare earth in the reaction kettle into the reaction kettle at a speed of 15 seconds per drip; s5, after the hydrofluoric acid solution is dripped, dripping an oxalic acid saturated solution into the supernatant solution in the reaction kettle, stopping dripping the oxalic acid saturated solution into the reaction kettle if no precipitate is generated, simultaneously, preserving the temperature of the reaction kettle for 2 hours for aging, and continuously dripping the oxalic acid saturated solution into the reaction kettle if the precipitate is generated until no precipitate is generated after dripping the oxalic acid saturated solution into the supernatant solution taken out of the reaction kettle; s6, taking out the precipitate in the reaction kettle, washing with water until the pH value is 6-8, drying at 120 ℃, calcining at 800-1150 ℃ for 5-8 hours, and finally adding a dispersing agent for grinding to obtain the rare earth fluoride polishing powder with the average particle size of 1.0-2.5 microns. The method needs to frequently judge whether the supernatant solution is dripped with the oxalic acid saturated solution to form a precipitate or not, so that the industrial production is difficult to realize. The oxalic acid saturated solution is dripped into the light rare earth acid solution, and then the oxalic acid saturated solution and the hydrofluoric acid solution are dripped into the light rare earth acid solution, so that the colloidal substance which is difficult to filter is easy to generate. In addition, the above method still uses oxalic acid as a precipitant, not an induced crystallization agent, resulting in a small particle size of the rare earth fluoride particles.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a method for preparing rare earth fluoride particles under acidic conditions, which has a large particle size of the product, is easily filtered, and has a high conversion rate of fluorine. Furthermore, the fluorine content of the waste liquid obtained by the preparation method is low.
Another object of the present invention is to provide a use of a carboxylic acid or a salt thereof for inducing crystallization of a rare earth fluoride under acidic conditions.
The invention achieves the above purpose through the following technical scheme.
The invention provides a method for preparing rare earth fluoride particles under acidic conditions, which comprises the following steps:
dripping the fluorine-containing acidic solution A and the soluble rare earth salt solution B into the base solution C in a parallel flow manner to react to obtain a mixed solution;
wherein, the fluorine-containing acid solution A is an acid solution containing a fluorinating agent; the soluble rare earth salt solution B is an aqueous solution containing soluble rare earth salt; the base solution C is water or an ammonium salt aqueous solution;
wherein, the fluorine-containing acidic solution A and/or the base solution C contain an acidity induced crystallization agent which is carboxylic acid or salt thereof capable of releasing free carboxylate radical in acidic medium.
According to the process of the present invention, preferably, RE is used3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 2.55-2.997.
According to the method of the present invention, it is preferable that the relative dropping speeds of the fluorine-containing acidic solution A and the soluble rare earth salt solution B are controlled so as to be RE during the concurrent dropping3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 1.5-3.5.
According to the method of the invention, preferably, the molar amount of the acid-induced crystallization agent in terms of carboxylate radicals is X, and the soluble rare earth salt in the soluble rare earth salt solution B is RE3+Calculating the molar quantity of the needed carboxylate radical as Y according to the molecular stoichiometric ratio on the basis, and then the dosage of the acid induced crystallization agent accords with the following formula:
X/Y＝0.1～20％。
according to the method, the parallel-flow dropping process is preferably carried out at 55-90 ℃.
According to the method of the present invention, preferably, the base solution C is an aqueous solution of an ammonium salt selected from one of ammonium chloride, ammonium sulfate and ammonium nitrate.
According to the method of the present invention, preferably, the soluble rare earth salt is selected from one of rare earth chloride, rare earth sulfate, rare earth nitrate and rare earth acetate;
the fluorinating agent is selected from one or more of hydrofluoric acid, fluosilicic acid and ammonium bifluoride;
the acidity-inducing crystallization agent is selected from one or more of oxalic acid, ammonium oxalate, sodium oxalate, rare earth oxalate, malonic acid, ammonium malonate, sodium malonate, propionic acid, ammonium propionate and sodium propionate.
According to the method of the present invention, preferably, the method further comprises the steps of:
and adjusting the pH value of the mixed solution to 5-7 by adopting ammonia water, filtering to obtain a filter cake, and drying and firing the filter cake to obtain the rare earth fluoride particles.
The invention also provides the application of the carboxylic acid or the salt thereof in inducing the rare earth fluoride to crystallize under the acidic condition.
According to the use of the present invention, preferably, a step of dropping a fluorine-containing acidic solution a and a soluble rare earth salt solution B into a base solution C in parallel for reaction to obtain a mixed solution;
wherein, the fluorine-containing acid solution A is an acid solution containing a fluorinating agent; the soluble rare earth salt solution B is an aqueous solution containing soluble rare earth salt; the base solution C is water or an ammonium salt aqueous solution;
wherein the fluorine-containing acidic solution A and/or the base solution C contain the carboxylic acid or a salt thereof as an acidity-inducing crystallization agent.
The method comprises the steps of dropwise adding a soluble rare earth salt aqueous solution and a fluorine-containing acidic solution into a base solution in a parallel-flow manner for reaction, wherein the base solution and/or the fluorine-containing acidic solution contain an acid induced crystallization agent, so that the rare earth fluoride is prepared. The product obtained by the method has large particle size, is easy to filter and has high fluorine conversion rate. Furthermore, the fluorine content in the waste liquid is low. According to the preferred embodiment of the present invention, the conversion of fluorine can be further improved by controlling the relative dropping rate during concurrent dropping.
Drawings
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
The present invention will be further described with reference to the following specific examples, but the scope of the present invention is not limited thereto.
"d" of the invention50"median diameter" or "median diameter" means the diameter corresponding to the percentage of the cumulative particle size distribution of a sample that reaches 50%. Its physical meaning is particle size greater thanIts particles account for 50% and particles smaller than it also account for 50%.
In the present invention, the conversion of fluorine is ═ F (as-Molar number of rare earth fluoride expressed as F-The number of moles of the fluorinating agent in the fluorine-containing acidic solution A) x 100%.
The method of the invention comprises the following steps: (1) a parallel-flow dropwise adding step; (2) and (5) post-processing. The process flow diagram refers to fig. 1. As described in detail below.
< concurrent dropwise addition step >
And (3) dropwise adding the fluorine-containing acidic solution A and the soluble rare earth salt solution B into the base solution C in a parallel flow manner to react to obtain a mixed solution. In the present invention, the order of addition is extremely important. The base solution of the invention does not contain soluble rare earth salt, thus being completely different from the prior art. The fluorine-containing acidic solution A and the soluble rare earth salt solution B need to be dripped in a parallel flow manner, so that the fluorine-containing acidic solution A and the soluble rare earth salt solution B can be ensured to have chemical reaction in time, and the crystallization of the rare earth fluoride is induced. This also makes it difficult to form a gel that is difficult to filter. The method of the invention does not need to frequently judge whether the supernatant forms the precipitate, thereby being beneficial to industrial production.
In the present invention, the fluorine-containing acidic solution a is an acidic solution containing a fluorinating agent; the soluble rare earth salt solution B is an aqueous solution containing soluble rare earth salt; the base solution C is water or an ammonium salt aqueous solution. The fluorine-containing acidic solution A and/or the base solution C contain an acidity-inducing crystallization agent. The base solution C before the start of the reaction contained no soluble rare earth salt. The resulting product has a large particle size, is easily filtered, and can improve the conversion of fluorine.
The present inventors have found that the grain size of rare earth carboxylates formed from carboxylic acids or carboxylates containing large steric bulk, such as oxalate, malonate, propionate, etc., is generally large. According to the theoretical mechanism that the solubility product ratio of the rare earth fluoride to the corresponding rare earth carboxylate is greater than 1, carboxylate radicals can firstly form corresponding rare earth carboxylate with rare earth ions, then the rare earth carboxylate reacts with fluoride ions in situ to be converted into the rare earth fluoride with a similar crystal structure, and simultaneously the carboxylate radicals are released. Thus, carboxylate radicals continue to participate in the next round of reaction to realize the effect of induced crystallization, so that the rare earth fluoride with larger grain diameter is obtained, and the generation of colloidal substances which are difficult to filter is avoided.
The acidity-induced crystallization agent of the present invention is a carboxylic acid or a salt thereof that can release a free carboxylate in an acidic medium. In certain embodiments, the acidity-induced crystallization agent of the present invention is a carboxylic acid that can release free carboxylate radicals in an acidic medium. The carboxylic acid of the present invention may be a monocarboxylic acid, a dicarboxylic acid or a polycarboxylic acid, preferably a monocarboxylic acid or a dicarboxylic acid, more preferably oxalic acid, propionic acid or malonic acid. In other embodiments, the acidity-induced crystallization agent of the present invention is a carboxylate salt that can release a free carboxylate in an acidic medium. The carboxylate of the present invention may be a monocarboxylate, a dicarboxylate or a polycarboxylate, preferably a monocarboxylate or dicarboxylate, more preferably an oxalate, propionate or malonate. Examples of carboxylates include, but are not limited to, oxalates, propionates, malonates, and the like. The carboxylate may be an alkali metal carboxylate, a rare earth metal carboxylate, an ammonium carboxylate, or the like. The alkali metal in the alkali metal carboxylic acid may be sodium or potassium. The rare earth metal in the rare earth metal carboxylate may be selected from one or more of lanthanum, cerium, yttrium, neodymium, dysprosium, samarium and ytterbium. The ammonium carboxylate salt may be ammonium oxalate, ammonium propionate or ammonium malonate. According to one embodiment of the invention, the acidity-inducing crystallization agent is selected from one or more of oxalic acid, ammonium oxalate, sodium oxalate, rare earth oxalates, malonic acid, ammonium malonate, sodium malonate, propionic acid, ammonium propionate and sodium propionate. The rare earth metal in the rare earth oxalate may be selected from one or more of lanthanum, cerium, yttrium, neodymium, dysprosium, samarium and ytterbium. The rare earth oxalate is preferably yttrium oxalate. Thus being beneficial to properly improving the particle size of the rare earth fluoride particles and avoiding the generation of colloidal substances.
The fluorine-containing acidic solution a of the present invention is an acidic solution containing a fluorinating agent. The fluorine-containing acidic solution a may be selected from one or more of hydrofluoric acid, fluorosilicic acid, and ammonium bifluoride solutions. Preferably, the fluorine-containing acidic solution a may be hydrofluoric acid or fluorosilicic acid. More preferably, the fluorine-containing acidic solution a is a mixed acid of hydrofluoric acid and fluorosilicic acid or a mixed solution of hydrofluoric acid and ammonium bifluoride. The fluorine-containing acidic solution A and the acidic induced crystallization agent are used in combination, so that the generation of colloidal substances can be avoided, and the particle size of the rare earth fluoride particles can be properly increased. In addition, the generation of fluorine-containing waste liquid can be avoided or the fluorine content in the waste liquid can be reduced, and the conversion rate of fluorine is improved.
The soluble rare earth salt solution B is an aqueous solution containing soluble rare earth salt. The soluble rare earth salt is selected from one of rare earth chloride, rare earth sulfate, rare earth nitrate and rare earth acetate. The rare earth metal in the soluble rare earth salt may be selected from one or more of lanthanum, cerium, yttrium, neodymium, dysprosium, samarium and ytterbium. Of course, the rare earth metal in the soluble rare earth salt may not be limited to these as long as an aqueous solution can be formed.
The base solution C is water or an ammonium salt aqueous solution. The type of the base solution C is very important to exert the function of the acidity-induced crystallization agent. The concentration of the ammonium salt aqueous solution may be 1 to 20 wt%, preferably 3 to 15 wt%, and more preferably 4 to 10 wt%. In addition, the base solution C may further contain an acid-induced crystallization agent. The ammonium salt in the ammonium salt aqueous solution is selected from one of ammonium chloride, ammonium sulfate and ammonium nitrate. In certain embodiments, the aqueous ammonium salt solution of the present invention is an ammonium sulfate wastewater, which can be used as a waste product.
The anion of the ammonium salt of the present invention is preferably the same as the anion in the soluble rare earth salt. For example, the rare earth salt is a rare earth sulfate, and the ammonium salt is ammonium sulfate. Thus being beneficial to properly improving the particle size of the rare earth fluoride particles and avoiding the generation of colloidal substances. Furthermore, this also reduces the effect of the anion on the acid-induced crystallization agent.
According to one embodiment of the present invention, the base solution C is an aqueous solution of an ammonium salt selected from one of ammonium chloride, ammonium sulfate and ammonium nitrate. According to another embodiment of the present invention, the soluble rare earth salt is selected from one of rare earth chloride, rare earth sulfate, rare earth nitrate and rare earth acetate; the fluorinating agent is selected from one or more of hydrofluoric acid, fluosilicic acid and ammonium bifluoride; the acidity-inducing crystallization agent is selected from one or more of oxalic acid, ammonium oxalate, sodium oxalate, rare earth oxalate, malonic acid, ammonium malonate, sodium malonate, propionic acid, ammonium propionate and sodium propionate.
The ion concentration during the reaction is a key factor affecting the particle size of the rare earth fluoride particles. The rare earth fluoride is synthesized by dripping the fluorine-containing acidic solution A and the soluble rare earth salt solution B into the base solution C in a parallel flow manner, so that RE can be effectively controlled3+Concentration and F-Concentration, lower concentration of RE3+And F-And continuing to grow on the surface of the formed rare earth fluoride particles to obtain larger particles. In the present invention, RE is used3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 2.55-2.997, preferably 1: 2.56-2.995, and more preferably 1: 2.57-2.99. The proportion of the rare earth fluoride and the fluorine-free waste liquid is controlled within the range, so that the rare earth fluoride particles with larger particle size can be obtained, the fluorine content in the waste liquid can be avoided, and even the fluorine-free waste liquid can be obtained.
The invention controls the dropping speed of the fluorine-containing acidic solution A and the soluble rare earth salt solution B, further controls the relative dropping molar ratio of the fluorine-containing acidic solution A and the soluble rare earth salt solution B, forms unbalanced reaction driving force, and fully plays the role of an acid induced crystallization agent, thereby promoting the grain size growth of rare earth fluoride particles and avoiding the generation of colloidal substances. In the invention, the relative dropping speed of the fluorine-containing acid solution A and the soluble rare earth salt solution B is controlled as follows: during the concurrent dropwise addition, RE is added3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 1.5-3.5, preferably 1: 1.55-3.48, and more preferably 1: 1.55-3.4. Thus being beneficial to improving the conversion rate of fluorine and ensuring that the fluorine content in the waste liquid is lower. In addition, the method is favorable for fully playing the role of the acid induced crystallization agent, obtaining the rare earth fluoride particles with larger particle size and avoiding generating colloidal substances.
The parallel-flow dripping process of the fluorine-containing acidic solution A and the soluble rare earth salt solution B can be carried out at 55-90 ℃. Preferably, the parallel-flow dropping process is carried out at 57-90 ℃. More preferably, the parallel-flow dropping process is carried out at 60-88 ℃. This is beneficial to improving the conversion rate of fluorine and avoiding generating colloidal substances. The temperature during the cocurrent dropwise addition can be controlled in various ways, for example, the base liquid C is heated before the cocurrent dropwise addition and then maintained in the above temperature range.
The fluorine-containing acidic solution A and/or the base solution C contain an acidity-inducing crystallization agent. In certain embodiments, the fluorine-containing acidic solution a contains an acidity-inducing crystallization agent and the base solution C does not contain an acidity-inducing crystallization agent. In other embodiments, the base solution C contains an acid-induced crystallization agent and the fluorine-containing acidic solution a does not contain an acid-induced crystallization agent. In still other embodiments, both the fluorine-containing acidic solution a and the base solution C contain an acidity-inducing crystallization agent.
Assuming that the molar weight of the acid induced crystallization agent calculated by carboxylate radical is X, the soluble rare earth salt in the soluble rare earth salt solution B is RE3+Calculating the molar quantity of the needed carboxylate radical as Y according to the molecular stoichiometric ratio on the basis, and then the dosage of the acid induced crystallization agent accords with the following formula: and X/Y is 0.1-20%. Preferably, X/Y is 1.0 to 15%. More preferably, X/Y is 5.0 to 10.0%. Thus being beneficial to promoting the generation of rare earth fluoride particles with large particle size and being easy to filter.
The amount of the base solution C used in the present invention is not particularly limited. Preferably, the volume of the base liquid is equal to F-The ratio of the number of moles of the fluorinating agent in the fluorine-containing acidic solution A is 50 to 550ml:1mol, preferably 55 to 500ml:1mol, and more preferably 60 to 450ml:1 mol.
< post-treatment step >
And (3) dropwise adding the fluorine-containing acidic solution A and the soluble rare earth salt solution B into the base solution C in a parallel flow manner to react to obtain a mixed solution. And adjusting the pH value of the mixed solution to 5-7 by adopting ammonia water to obtain rare earth fluoride slurry, then filtering to obtain a filter cake, and drying and firing the filter cake to obtain rare earth fluoride particles. The invention discovers that the NH is generated by adding ammonia water into the mixed solution after the complete reaction4 +Is adsorbed by the negatively charged rare earth fluoride particles, and a bridging effect is formed among the rare earth fluoride particles with smaller particle size, thereby effectively promoting the further growth of the rare earth fluoride particles and improving the easy filterability and fluidity of the product. This is advantageous in further increasing the particle size of the rare earth fluoride particlesEven clean fluorine-free wastewater is formed.
In the present invention, the concentration of the ammonia water may be 15 to 28 wt%, preferably 18 to 28 wt%, and more preferably 20 to 28 wt%. The invention can directly use strong ammonia water, thus reducing the waste water amount.
In the present invention, since the rare earth fluoride slurry is easily filtered, the manner of filtering is not particularly limited. For example, filtration under reduced pressure is employed to obtain a filter cake and a filtrate. And leaching or washing the filter cake, and then drying and burning. The drying temperature can be 100-180 ℃, and the drying time is 1-5 h. Preferably, the drying temperature is 105-170 ℃, and the drying time is 1.5-4.5 h. More preferably, the drying temperature is 110-160 ℃ and the drying time is 1.5-4 h. The burning temperature can be 550-750 ℃, and the burning time is 1-7 h. Preferably, the burning temperature is 555-745 ℃, and the burning time is 1.5-6.5 h. More preferably, the burning temperature is 560-740 ℃, and the burning time is 1.5-6.0 h. The obtained filtrate (namely the waste liquid) has lower fluorine content, and even the fluorine-free waste liquid is obtained.
According to one embodiment of the invention, a fluorine-containing acid solution A and a soluble rare earth salt solution B are dripped into a base solution C (the base solution C contains an acid induced crystallization agent) in a parallel flow manner at 60-90 ℃, and the relative dripping speed of the fluorine-containing acid solution A and the soluble rare earth salt solution B is controlled during the parallel flow dripping process to obtain a mixed solution; wherein, RE is3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 2.55-2.997; controlling the relative dropping speed of A and B to enable RE3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 1.5-3.5; and adjusting the pH value of the mixed solution by using ammonia water, filtering to obtain a filter cake and filtrate, and drying and firing the filter cake to obtain the rare earth fluoride particles.
< use of carboxylic acid or salt thereof >
The present inventors have found that the grain size of rare earth carboxylates formed from carboxylic acids or carboxylates containing large steric bulk, such as oxalate, malonate, propionate, etc., is generally large. According to the theoretical mechanism that the solubility product ratio of the rare earth fluoride to the corresponding rare earth carboxylate is greater than 1, carboxylate radicals can firstly form corresponding rare earth carboxylate with rare earth ions, then the rare earth carboxylate reacts with fluoride ions in situ to be converted into the rare earth fluoride with a similar crystal structure, and the carboxylate radicals are released at the same time. Thus, carboxylate radicals continue to participate in the next round of reaction to realize the effect of induced crystallization, so that the rare earth fluoride with larger grain diameter is obtained, and the generation of colloidal substances which are difficult to filter is avoided. Thus, the invention also provides the use of a carboxylic acid or a salt thereof to induce crystallization of a rare earth fluoride under acidic conditions.
The carboxylic acid of the present invention may be a monocarboxylic acid, a dicarboxylic acid or a polycarboxylic acid, preferably a monocarboxylic acid or a dicarboxylic acid, more preferably oxalic acid, propionic acid or malonic acid. The carboxylate of the present invention may be a monocarboxylate, a dicarboxylate or a polycarboxylate, preferably a monocarboxylate or dicarboxylate, more preferably an oxalate, propionate or malonate. Examples of carboxylates include, but are not limited to, oxalates, propionates, malonates, and the like. The carboxylate may be an alkali metal carboxylate, a rare earth metal carboxylate, an ammonium carboxylate, or the like. The alkali metal in the alkali metal carboxylic acid may be selected from sodium or potassium. The rare earth metal in the rare earth metal carboxylate may be selected from one or more of lanthanum, cerium, yttrium, neodymium, dysprosium, samarium and ytterbium. The ammonium carboxylate salt may be selected from ammonium oxalate, ammonium propionate or ammonium malonate. According to one embodiment of the invention, the carboxylic acid or salt thereof is selected from one or more of oxalic acid, ammonium oxalate, sodium oxalate, rare earth oxalates, malonic acid, ammonium malonate, sodium malonate, propionic acid, ammonium propionate and sodium propionate. The rare earth metal in the rare earth oxalate may be selected from one or more of lanthanum, cerium, yttrium, neodymium, dysprosium, samarium and ytterbium. The rare earth oxalate is preferably yttrium oxalate. Thus being beneficial to properly improving the particle size of the rare earth fluoride particles and avoiding the generation of colloidal substances.
According to one embodiment of the present invention, the above use includes a step of adding a fluorine-containing acidic solution a and a soluble rare earth salt solution B dropwise into a base solution C in parallel to react to obtain a mixed solution; wherein, the fluorine-containing acid solution A is an acid solution containing a fluorinating agent; the soluble rare earth salt solution B is an aqueous solution containing soluble rare earth salt; the base solution C is water or an ammonium salt aqueous solution; wherein the fluorine-containing acidic solution A and/or the base solution C contain the carboxylic acid or a salt thereof as an acidity-inducing crystallization agent.
According to the use of the present invention, the fluorine-containing acidic solution a may be selected from one or more of hydrofluoric acid, fluorosilicic acid, and ammonium bifluoride solutions. Preferably, the fluorine-containing acidic solution a may be hydrofluoric acid or fluorosilicic acid. More preferably, the fluorine-containing acidic solution a is a mixed acid of hydrofluoric acid and fluorosilicic acid or a mixed solution of hydrofluoric acid and ammonium bifluoride. The fluorine-containing acidic solution A and the acidic induced crystallization agent are used in combination, so that the generation of colloidal substances can be avoided, and the particle size of the rare earth fluoride particles can be properly increased. In addition, the generation of fluorine-containing waste liquid can be avoided or the fluorine content in the waste liquid can be reduced, and the conversion rate of fluorine is improved.
According to the use of the invention, the soluble rare earth salt solution B of the invention is an aqueous solution containing a soluble rare earth salt. The soluble rare earth salt is selected from one of rare earth chloride, rare earth sulfate, rare earth nitrate and rare earth acetate. The rare earth metal in the soluble rare earth salt may be selected from one or more of lanthanum, cerium, yttrium, neodymium, dysprosium, samarium and ytterbium. Of course, the rare earth metal in the soluble rare earth salt may not be limited to these as long as an aqueous solution can be formed.
According to the use of the invention, the base liquid C of the invention is water or an aqueous ammonium salt solution. The type of the base solution C is very important to exert the function of the acidity-induced crystallization agent. The concentration of the ammonium salt aqueous solution may be 1 to 20 wt%, preferably 3 to 15 wt%, more preferably 4 to 10 wt%. Further, the base solution C may further contain the carboxylic acid or a salt thereof as an acidity-inducing crystallization agent. The ammonium salt in the ammonium salt aqueous solution is selected from one of ammonium chloride, ammonium sulfate and ammonium nitrate. In certain embodiments, the aqueous ammonium salt solution of the present invention is ammonium sulfate wastewater, which can be waste-utilized.
The anion of the ammonium salt of the present invention is preferably the same as the anion in the soluble rare earth salt. For example, the rare earth salt is a rare earth sulfate, and the ammonium salt is ammonium sulfate. Thus being beneficial to properly improving the particle size of the rare earth fluoride particles and avoiding the generation of colloidal substances. Furthermore, this also reduces the effect of the anion on the acid-induced crystallization agent.
According to one embodiment of the present invention, the base solution C is an aqueous solution of an ammonium salt selected from one of ammonium chloride, ammonium sulfate and ammonium nitrate. According to another embodiment of the present invention, the soluble rare earth salt is selected from one of rare earth chloride, rare earth sulfate, rare earth nitrate and rare earth acetate; the fluorinating agent is selected from one or more of hydrofluoric acid, fluosilicic acid and ammonium bifluoride; the acidity-inducing crystallizing agent is one or more selected from oxalic acid, ammonium oxalate, sodium oxalate, rare earth oxalate, malonic acid, ammonium malonate, sodium malonate, propionic acid, ammonium propionate and sodium propionate.
The ion concentration during the reaction is a key factor affecting the particle size of the rare earth fluoride particles. The rare earth fluoride is synthesized by dripping the fluorine-containing acidic solution A and the soluble rare earth salt solution B into the base solution C in a parallel flow manner, so that RE can be effectively controlled3+Concentration and F-Concentration, lower concentration of RE3+And F-And continuing to grow on the surface of the formed rare earth fluoride particles to obtain larger particles. In the present invention, RE is used3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 2.55-2.997, preferably 1: 2.56-2.995, and more preferably 1: 2.57-2.99. The proportion of the rare earth fluoride and the fluorine-free waste liquid is controlled within the range, so that the rare earth fluoride particles with larger particle size can be obtained, the fluorine content in the waste liquid can be avoided, and even the fluorine-free waste liquid can be obtained.
The invention controls the dropping speed of the fluorine-containing acidic solution A and the soluble rare earth salt solution B, further controls the relative dropping molar ratio of the fluorine-containing acidic solution A and the soluble rare earth salt solution B, forms unbalanced reaction driving force, and fully plays the role of an acid induced crystallization agent, thereby promoting the grain size growth of rare earth fluoride particles and avoiding the generation of colloidal substances. In the present invention, the relative dropping speeds of the fluorine-containing acidic solution A and the soluble rare earth salt solution B are controlled as follows: during the concurrent dropwise addition, as RE3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 1.5-3.5, preferably 1: 1.55-3.48, and more preferably 1: 1.55-3.4. Thus being beneficial to improving the conversion rate of fluorine and ensuring that the fluorine content in the waste liquid is lower. In addition, the method is favorable for fully playing the role of the acid induced crystallization agent, obtaining the rare earth fluoride particles with larger particle size and avoiding generating colloidal substances.
The parallel-flow dripping process of the fluorine-containing acidic solution A and the soluble rare earth salt solution B can be carried out at 55-90 ℃. Preferably, the parallel-flow dropping process is carried out at 57-90 ℃. More preferably, the parallel-flow dropping process is carried out at 60-88 ℃. This is beneficial to improving the conversion rate of fluorine and avoiding generating colloidal substances. The temperature during the cocurrent dropwise addition can be controlled in various ways, for example, the base liquid C is heated before the cocurrent dropwise addition and then maintained in the above temperature range.
The fluorine-containing acidic solution A and/or the base solution C contain the carboxylic acid or a salt thereof as an acidity-inducing crystallization agent. In certain embodiments, the fluorine-containing acidic solution a contains the carboxylic acid or salt thereof as an acid-induced crystallization agent, and the base solution C does not contain an acid-induced crystallization agent. In other embodiments, the base solution C contains the carboxylic acid or salt thereof as an acid-induced crystallization agent, and the fluorine-containing acidic solution a does not contain an acid-induced crystallization agent. In still other embodiments, the fluorine-containing acidic solution a and the base solution C each contain the carboxylic acid or a salt thereof as an acidity-induced crystallization agent.
Assuming that the molar weight of the acid induced crystallization agent calculated by carboxylate radical is X, the soluble rare earth salt in the soluble rare earth salt solution B is calculated by RE3+Calculating the molar quantity of the needed carboxylate radical as Y according to the molecular stoichiometric ratio on the basis, and then the dosage of the acid induced crystallization agent accords with the following formula: X/Y is 0.1-20%. Preferably, X/Y is 1.0 to 15%. More preferably, X/Y is 5.0 to 10.0%. Thus being beneficial to promoting the generation of rare earth fluoride particles with large particle size and being easy to filter.
The amount of the base solution C used in the present invention is not particularly limited. Preferably, the volume of the base liquid is equal to F-The ratio of the number of moles of the fluorinating agent in the fluorine-containing acidic solution A is 50 to 550ml:1mol, preferably 55 to 500ml:1mol, more preferably 55 to 500ml:1mol1mol of 60-450 ml.
The invention may also include the steps of: and adjusting the pH value of the mixed solution to 5-7 by adopting ammonia water to obtain rare earth fluoride slurry, then filtering to obtain a filter cake, and drying and firing the filter cake to obtain rare earth fluoride particles. The invention discovers that ammonia water is added into the mixed solution after complete reaction to generate NH4 +Is adsorbed by the negatively charged rare earth fluoride particles, and a bridging effect is formed among the rare earth fluoride particles with smaller particle size, thereby effectively promoting the further growth of the rare earth fluoride particles and improving the easy filterability and fluidity of the product. Thus being beneficial to further improving the particle size of the rare earth fluoride particles and even forming clean fluorine-free wastewater.
According to the application of the invention, the concentration of the ammonia water can be 15-28 wt%, preferably 18-28 wt%, and more preferably 20-28 wt%.
Since the rare earth fluoride slurry is easily filtered, the manner of filtering is not particularly limited. For example, filtration under reduced pressure is employed to obtain a filter cake and a filtrate. And leaching or washing the filter cake, and then drying and burning. The drying temperature can be 100-180 ℃, and the drying time is 1-5 h. Preferably, the drying temperature is 105-170 ℃, and the drying time is 1.5-4.5 h. More preferably, the drying temperature is 110-160 ℃ and the drying time is 1.5-4 h. The burning temperature can be 550-750 ℃, and the burning time is 1-7 h. Preferably, the burning temperature is 555-745 ℃, and the burning time is 1.5-6.5 h. More preferably, the burning temperature is 560-740 ℃, and the burning time is 1.5-6.0 h. The obtained filtrate (namely the waste liquid) has lower fluorine content, and even the fluorine-free waste liquid is obtained.
According to one embodiment of the invention, a fluorine-containing acid solution A and a soluble rare earth salt solution B are dripped into a base solution C (the base solution C contains an acid induced crystallization agent) in a parallel flow manner at 60-90 ℃, and the relative dripping speed of the fluorine-containing acid solution A and the soluble rare earth salt solution B is controlled during the parallel flow dripping process to obtain a mixed solution; wherein, RE is3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 2.55-2.997; controlThe relative dropping speed of the preparation of A and B is enabled to be RE3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 1.5-3.5; and adjusting the pH value of the mixed solution by using ammonia water, filtering to obtain a filter cake and filtrate, and drying and firing the filter cake to obtain the rare earth fluoride particles.
In the following examples and comparative examples, the "fluorine concentration" is defined as F-The molar concentration of the fluorinating agent in the fluorine-containing acidic solution A is measured.
Example 1
163ml of lanthanum chloride aqueous solution (REO, 297g/L) and 223ml of hydrofluoric acid solution with fluorine concentration of 4.0mol/L were added dropwise to 100ml of deionized water (base solution) containing 0.02g of oxalic acid under concurrent flow at 60 ℃, and a mixed solution was obtained after the reaction was completed. The dropping speed of the lanthanum chloride aqueous solution and the hydrofluoric acid solution is 1ml/min and 1.6ml/min respectively.
The mixture was adjusted to pH 6 with 60ml of aqueous ammonia (25% by weight), and then filtered to obtain a cake and a filtrate. Drying and burning the filter cake to obtain the lanthanum fluoride-containing particles.
Example 2
At 70 ℃, 152ml of lanthanum cerium chloride aqueous solution (REO, 283g/L) and 216ml of fluosilicic acid solution (fluorine concentration is 3.5mol/L) containing 0.21g of ammonium oxalate are dripped into 50ml of deionized water (base solution) in a concurrent flow manner, and mixed solution is obtained after complete reaction. The dropping speed of the lanthanum cerium chloride aqueous solution and the fluosilicic acid solution is 1.2ml/min and 1.8ml/min respectively.
The mixture was adjusted to pH 7 with 83ml of aqueous ammonia (25% by weight), and then filtered to obtain a cake and a filtrate. Drying and burning the filter cake to obtain the lanthanum fluoride cerium particles.
Example 3
1149ml of a cerium sulfate aqueous solution (REO, 38g/L) and 135ml of a fluorine-containing acidic solution (fluorine concentration is 5.5mol/L, molar ratio of hydrofluoric acid to fluorosilicic acid is 1:1) formed by hydrofluoric acid and fluorosilicic acid were added dropwise concurrently to 300ml of ammonium sulfate wastewater (bottom solution, ammonium sulfate concentration is 3 wt%) containing 0.37g of oxalic acid and 0.5g of ammonium oxalate at 75 ℃, and a mixed solution was obtained after completion of the reaction. The dropping speed of the cerium sulfate aqueous solution and the fluorine-containing acid solution is 7.2ml/min and 0.8ml/min respectively.
The mixture was adjusted to pH 5 with 60ml of aqueous ammonia (25% by weight), and then filtered to obtain a cake and a filtrate. Drying and burning the filter cake to obtain cerium fluoride particles.
Example 4
143ml of an aqueous yttrium nitrate solution (REO, 269g/L) and 97ml of a fluorine-containing acidic solution of hydrofluoric acid and ammonium bifluoride (fluorine concentration 10.0mol/L, F) were added at 80 ℃-And NH4 +At a molar ratio of 1:0.20) and added dropwise to 50ml of deionized water (base solution) containing 13.3g of yttrium oxalate, and a mixed solution is obtained after the reaction is completed. The dropping rates of the yttrium nitrate aqueous solution and the fluorine-containing acid solution are respectively 0.9ml/min and 0.5 ml/min.
The mixture was adjusted to pH 6 with 72ml of aqueous ammonia (25% by weight) and filtered to obtain a cake and a filtrate. Drying and burning the filter cake to obtain the yttrium fluoride particles.
Example 5
169ml of an aqueous samarium chloride solution (REO, 257g/L) and 75ml of a hydrofluoric acid solution (fluorine concentration: 9.5mol/L) were added dropwise concurrently to 100ml of an aqueous ammonium chloride solution (ammonium chloride concentration: 6 wt%) containing 1.22g of propionic acid at 90 ℃ to complete the reaction to obtain a mixed solution. The dropping speed of the samarium chloride water solution and the hydrofluoric acid solution is 2.1ml/min and 0.6ml/min respectively.
The mixture was adjusted to pH 6 with 55ml of ammonia (25 wt% strength), filtered and rinsed with a small amount of water to give a filter cake and a filtrate. Drying and burning the filter cake to obtain samarium fluoride particles.
Example 6
172ml of ytterbium nitrate aqueous solution (REO, 293g/L) and 93ml of a fluorine-containing acidic solution of hydrofluoric acid and ammonium bifluoride (fluorine concentration 8.0mol/L, F) were added at 90 ℃-And NH4 +At a molar ratio of 1:0.45) and added dropwise to 50ml of deionized water (base solution) containing 0.98g of ammonium propionate, and a mixed solution is obtained after the reaction is completed. Ytterbium nitrate aqueous solutionThe dropping rate of the fluorine-containing acidic solution was 3.2ml/min and 0.9ml/min, respectively.
The mixture was adjusted to pH 7 with 55ml of aqueous ammonia (25% by weight) and filtered to obtain a cake and a filtrate. Drying and burning the filter cake to obtain ytterbium fluoride particles.
Example 7
147ml of an aqueous neodymium nitrate solution (REO, 263g/L) and 80ml of an ammonium bifluoride solution (fluorine concentration of 8.0mol/L) were added dropwise and concurrently to 100ml of an ammonium nitrate solution (base solution, ammonium nitrate concentration of 5 wt%) containing 2.39g of malonic acid at 85 ℃ to obtain a mixed solution after completion of the reaction. The dropping rates of the neodymium nitrate aqueous solution and the ammonium bifluoride solution are respectively 1.2ml/min and 0.5 ml/min.
The mixture was adjusted to pH 6 with 50ml of ammonia (25% by weight) and filtered to obtain a cake and a filtrate. Drying and burning the filter cake to obtain neodymium fluoride particles.
Example 8
191ml of dysprosium acetate aqueous solution (REO, 223g/L) and 62ml of a fluorine-containing acidic solution of hydrofluoric acid and ammonium bifluoride (fluorine concentration 10.5mol/L, F) were added at 90 ℃-And NH4 +Molar ratio of 1:0.35) and dropwise added into 50ml of deionized water (base solution) containing 2.50g of ammonium malonate, and mixed solution is obtained after complete reaction. The dropping rates of the neodymium nitrate aqueous solution and the fluorine-containing acidic solution are respectively 1.3ml/min and 0.3 ml/min.
The mixture was adjusted to pH 7 with 75ml of ammonia (25% by weight) and filtered to obtain a cake and a filtrate. Drying and burning the filter cake to obtain dysprosium fluoride particles.
Comparative example 1
This comparative example differs from example 1 mainly in that the cocurrent dropwise addition mode is not employed. The rare earth salt solution is added into the base solution, and then the fluorine-containing acidic solution is added. The details are as follows:
163ml of lanthanum chloride aqueous solution (REO, 297g/L) was added dropwise to 100ml of deionized water (base solution) containing 0.02g of oxalic acid at 60 ℃, then 223ml of hydrofluoric acid solution having a fluorine concentration of 4.0mol/L was added dropwise, and a mixed solution was obtained after the reaction was completed. The dropping rates of the lanthanum chloride aqueous solution and the hydrofluoric acid solution are respectively 1ml/min and 1.6 ml/min.
The mixture was adjusted to pH 6 with 60ml of aqueous ammonia (25% by weight), and then filtered to obtain a cake and a filtrate. Drying and burning the filter cake to obtain the lanthanum fluoride-containing particles.
Comparative example 2
Lanthanum fluoride particles were prepared using example 3 of CN 101607733A.
TABLE 1
Note: m represents by RE3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The calculated molar ratio of the fluorinating agent in the fluorine-containing acidic solution A; n represents RE in the course of cocurrent dropwise addition3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is calculated.
The present invention is not limited to the above-described embodiments, and any variations, modifications, and substitutions which may occur to those skilled in the art may be made without departing from the spirit of the invention.
Claims (5)
1. A method for preparing rare earth fluoride particles under acidic conditions, comprising the steps of:
at the temperature of 55-90 ℃, dropwise adding the fluorine-containing acidic solution A and the soluble rare earth salt solution B into the base solution C in a parallel flow manner to react to obtain a mixed solution;
adjusting the pH value of the mixed solution to 5-7 by adopting ammonia water, then filtering to obtain a filter cake, and drying and firing the filter cake to obtain rare earth fluoride particles;
wherein, the fluorine-containing acid solution A is an acid solution containing a fluorinating agent; the soluble rare earth salt solution B is an aqueous solution containing soluble rare earth salt; the base solution C is water or an ammonium salt aqueous solution;
wherein, the fluorine-containing acidic solution A and/or the base solution C contain an acidity-induced crystallization agent which is carboxylic acid or salt thereof capable of releasing free carboxylate radicals in an acidic medium; the acidity induced crystallization agent is selected from one or more of oxalic acid, ammonium oxalate, sodium oxalate, rare earth oxalate, malonic acid, ammonium malonate, sodium malonate, propionic acid, ammonium propionate and sodium propionate;
wherein the molar weight of the acid induced crystallization agent in terms of carboxylate radical is X, and the soluble rare earth salt in the soluble rare earth salt solution B is RE3+Calculating the molar quantity of the needed carboxylate radical as Y according to the molecular stoichiometric ratio on the basis, and then the dosage of the acid induced crystallization agent accords with the following formula:
X/Y＝0.1～15％；
wherein, RE is3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 2.55-2.997.
2. The method of claim 1, wherein the relative dropping rates of the fluorine-containing acidic solution A and the soluble rare earth salt solution B are controlled such that RE is present during the concurrent dropping3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 1.5-3.5.
3. The method according to any one of claims 1 to 2, wherein the base solution C is an aqueous solution of an ammonium salt selected from one of ammonium chloride, ammonium sulfate and ammonium nitrate.
4. The method according to any one of claims 1 to 2, wherein:
the soluble rare earth salt is selected from one of rare earth chloride, rare earth sulfate, rare earth nitrate and rare earth acetate;
the fluorinating agent is selected from one or more of hydrofluoric acid, fluosilicic acid and ammonium bifluoride.
5. Use of a carboxylic acid or salt thereof to induce crystallization of a rare earth fluoride under acidic conditions, comprising: at the temperature of 55-90 ℃, dropwise adding the fluorine-containing acidic solution A and the soluble rare earth salt solution B into the base solution C in a parallel flow manner to react to obtain a mixed solution;
adjusting the pH value of the mixed solution to 5-7 by adopting ammonia water, then filtering to obtain a filter cake, and drying and firing the filter cake to obtain rare earth fluoride particles;
wherein, the fluorine-containing acid solution A is an acid solution containing a fluorinating agent; the soluble rare earth salt solution B is an aqueous solution containing soluble rare earth salt; the base solution C is water or an ammonium salt aqueous solution;
wherein the fluorine-containing acidic solution A and/or the base solution C contain the carboxylic acid or a salt thereof as an acidity-induced crystallization agent; the acidity induced crystallization agent is selected from one or more of oxalic acid, ammonium oxalate, sodium oxalate, rare earth oxalate, malonic acid, ammonium malonate, sodium malonate, propionic acid, ammonium propionate and sodium propionate;
wherein the molar weight of the acid induced crystallization agent in terms of carboxylate radical is X, and the soluble rare earth salt in the soluble rare earth salt solution B is RE3+Calculating the molar weight of the needed carboxylate radical as Y according to the molecular stoichiometric ratio by taking the reference as a reference, wherein the dosage of the acidic induced crystallization agent accords with the following formula:
X/Y＝0.1～15％；
wherein, RE is3+The soluble rare earth salt in the soluble rare earth salt solution B is counted as F-The molar ratio of the fluorinating agent in the fluorine-containing acidic solution A is 1: 2.55-2.997.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3667921A (en) * | 1969-08-07 | 1972-06-06 | Bell Telephone Labor Inc | Flux growth of rare earth fluorides |
| US5013534A (en) * | 1988-07-01 | 1991-05-07 | Rhone-Poulenc Chimie | Morphologically improved rare earth trifluorides |
| CN101284983A (en) * | 2007-04-12 | 2008-10-15 | 北京有色金属研究总院 | Superfine and spheroidizing rare-earth polish and preparing process thereof |
| CN101306828A (en) * | 2007-05-17 | 2008-11-19 | 北京有色金属研究总院 | Device and process for preparing rare-earth compound uniform micro powder |
| CN101607733A (en) * | 2008-06-19 | 2009-12-23 | 天津市化学试剂研究所 | With the rare earth oxide is the method for feedstock production rare earth fluorine |
| CN108752190A (en) * | 2018-06-27 | 2018-11-06 | 湖南稀土金属材料研究院 | The preparation method of double oxalate of rare earth ammonium and the preparation method of rare earth oxide |
| CN110372026A (en) * | 2019-07-18 | 2019-10-25 | 赣州湛海新材料科技有限公司 | A kind of rare earth fluoride preparation method applied to crystalline material |
| CN110494393A (en) * | 2017-02-03 | 2019-11-22 | 南非核能源国营有限公司 | The preparation method of rare earth metal fluoride |
-
2020
- 2020-01-21 CN CN202010068893.9A patent/CN111252797B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3667921A (en) * | 1969-08-07 | 1972-06-06 | Bell Telephone Labor Inc | Flux growth of rare earth fluorides |
| US5013534A (en) * | 1988-07-01 | 1991-05-07 | Rhone-Poulenc Chimie | Morphologically improved rare earth trifluorides |
| CN101284983A (en) * | 2007-04-12 | 2008-10-15 | 北京有色金属研究总院 | Superfine and spheroidizing rare-earth polish and preparing process thereof |
| CN101306828A (en) * | 2007-05-17 | 2008-11-19 | 北京有色金属研究总院 | Device and process for preparing rare-earth compound uniform micro powder |
| CN101607733A (en) * | 2008-06-19 | 2009-12-23 | 天津市化学试剂研究所 | With the rare earth oxide is the method for feedstock production rare earth fluorine |
| CN110494393A (en) * | 2017-02-03 | 2019-11-22 | 南非核能源国营有限公司 | The preparation method of rare earth metal fluoride |
| CN108752190A (en) * | 2018-06-27 | 2018-11-06 | 湖南稀土金属材料研究院 | The preparation method of double oxalate of rare earth ammonium and the preparation method of rare earth oxide |
| CN110372026A (en) * | 2019-07-18 | 2019-10-25 | 赣州湛海新材料科技有限公司 | A kind of rare earth fluoride preparation method applied to crystalline material |
Non-Patent Citations (2)
| Title |
|---|
| "氟化稀土的制备及组成研究";王亚军等;《内蒙古大学学报(自然科学版)》;19980930;第29卷(第5期);667-671 * |
| 稀土草酸盐直接制备氟化物的试验研究;董素霞;《江西有色金属》;20001230(第04期);全文 * |
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