CN102978399B - Method for producing low chloride fine particle high purity rare earth compound through ultrasonic-assisted oxalate deposition - Google Patents
Method for producing low chloride fine particle high purity rare earth compound through ultrasonic-assisted oxalate deposition Download PDFInfo
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- CN102978399B CN102978399B CN201210532240.7A CN201210532240A CN102978399B CN 102978399 B CN102978399 B CN 102978399B CN 201210532240 A CN201210532240 A CN 201210532240A CN 102978399 B CN102978399 B CN 102978399B
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Abstract
The invention relates to a new method for producing low chloride fine particle rare earth compound through directly depositing rare earth with oxalate and salt thereof taken from hydrochloric acid medium, which is mainly characterized by comprising the following steps of carrying out the process of depositing the rare earth through charging reaction under ultrasonic assistance, obtaining relevant low chloride oxalate rare earth through steps of ageing crystallization and filtration and washing, and obtaining relevant rare earth oxide products through calcination. The method is simple and easy to apply, and has wide application; according to the method, the consumption of washing water is reduced, high purity rare earth product with chloride below 50ppm can be obtained, therefore, the method can be used for producing single rare earth and rare earth co-precipitate.
Description
Technical field
The present invention relates to the preparation method of the low chlorine root of class fine granularity rare earth compound, its principal feature is in rare-earth oxalate precipitation process, to have taked ultrasonic wave ancillary technique, realized directly from hydrochloric acid medium precipitating rare earth and obtain the dual purpose of low chloride content and subparticle rare earth compound material.Belong to rare-earth wet method metallurgy and rare earth material field.
Technical background
The production technology of high purity rare earth compound is the gordian technique that meets Rare Earth Functional Materials application requiring.Since the nineties in last century, University Of Nanchang has solved the technical barrier of directly producing low chlorine root carbonated rare earth and rare earth oxide from hydrochloric acid medium by carbonate and oxalate precipitation method in rare-earth precipitation and crystallization technique research, and be widely used, for production and the application of China's low chlorine root high purity rare-earth products provide modern technique.In recent years, the application to rare earth that rises rapidly of rare-earth products price brought very large pressure, and many rare earths are applied enterprise rare-earth products has been proposed to new requirement.Wherein a main requirement is further reducing of product particle.For example: in fluorescent material field, in order to reduce fluorescent material consumption, fluorescent powder grain further need to be reduced to reduce the coating thickness of phosphor powder layer, wish that the particle of the material presomas such as yttrium oxide is reduced to 2 microns from 5 microns of left and right; In opticglass production process, require the granularity of lanthanum trioxide to be reduced to several micron from tens microns, to increase the dispersing property of lanthanum trioxide in melten glass material.But the existing precipitator method are difficult to meet these requirements.For this reason, need to develop the new technology that can simultaneously meet high purity rare earth compound material chloride content and granularity requirement.The present invention proposes for addressing this problem just.
Summary of the invention
The present invention is directed to the deficiencies in the prior art, provide a kind of ultrasonic wave auxiliary rare-earth oxalate precipitated crystal method, that is: under ultrasonic wave is auxiliary, carry out the precipitation operation of rare earth oxalate, utilize hyperacoustic cavitation effect to reduce the secondary crystal behavior of precipitation process, increase by one time nucleation rate, reduce particle surface electrical simultaneously, thereby reach reduction granular size, reduce the dual purpose that chlorion is carried secretly.
Processing step of the present invention is as follows:
[1] in precipitin reaction still pot, tank or groove, inject in advance oxalic acid solution, or the suspension that contains rare earth oxalate and dilute hydrochloric acid water, its volume can stir solution or suspension to be as the criterion with stirring arm, and the precipitation temperature control that makes solution temperature reach setting requires 1-100 ℃;
[2] under the precipitation temperature of setting, dissolve oxalic acid to saturated or approach saturation concentration, reinforced volume ratio according to rare earth with the ratio 1:1.5-1:1.8 of the amount of substance of oxalic acid and the densitometer equation in calculation acid solution of oxalic acid solution and rare earth feed liquid and rare earth feed liquid, calculate feed rate according to feed way and reaction times requirement, under hyperacoustic effect, complete charging reaction precipitation process; The temperature of rare earth feed liquid is the precipitation temperature scope that normal temperature arrives setting;
[3] after reinforced, can stop ultrasonic, ageing 1-6h after continuing to stir, or ultrasound precipitation slurry is proceeded to another reactor pot or groove carries out ageing 0.5-10h;
[4] after ageing, supernatant liquor is separated, precipitation continues to add water washing until can't detect the existence of chlorion in wash filtrate with silver nitrate solution;
[5] enter calcination process through the rare earth oxalate of washing and filtering dehydration, between 800-1400 ℃, calcine 1-6h, can obtain required low chlorine root fine granularity rare earth oxide.
Described rare earth feed liquid can be the one in Yttrium trichloride+europium, Lanthanum trichloride, Yttrium trichloride feed liquid.
In precipitation and ageing process, ultrasonic wave all has contribution for refinement particle and reduction chlorine root, but with the effect maximum in charging reaction process.Therefore, ultrasonic time should than the charging reaction time quite or slightly long.Extend ultrasonic time for the chloride content reducing in product, reduce not significantly impact of grain graininess.Therefore, consider from energy-conservation angle, ageing and washing process can be cancelled ultrasonic.
The invention has the beneficial effects as follows:
The present invention is simple, only need in existing precipitation and crystallization reaction equipment, increase ultrasonic generator and transmission part thereof.Under ul-trasonic irradiation, complete charging reaction precipitation process, the precipitation of formation is followed aging crystallization at a certain temperature, washs subsequently, filters and obtains rare-earth oxalate, after calcining, can obtain corresponding oxide product.Be suitable for precipitation and the Crystallization Procedure of various rare-earth oxalates, obtain the high purity rare-earth products that particle is little, chloride content is low.Its chloride content can be controlled at below 50ppm.Grain graininess is relevant with rare earth element kind, and for yttrium oxide series product, its granularity can be controlled between 2-3 micron, and for lanthanum trioxide series product, its granularity is between 4-6 micron.
Accompanying drawing explanation
Under Fig. 1 ultrasonication, the electromicroscopic photograph of oxalic acid inverted sequence precipitation yttrium europium gained oxide compound, shows that granular size is 2 microns of left and right;
Under Fig. 2 ultrasonication, the XRD diffractogram of oxalic acid inverted sequence precipitation yttrium europium gained yttrium oxalate europium, shows its well-crystallized, is typical yttrium oxalate crystallization;
Under Fig. 3 ultrasonication, the electromicroscopic photograph of oxalic acid positive sequence precipitation lanthanum gained oxide compound, shows the not aggregate of strip crystallization of particle, and particle is 5 microns of left and right;
Under Fig. 4 ultrasonication, the XRD diffractogram of oxalic acid synchronous precipitation lanthanum gained lanthanum oxalate is shown in, shows that precipitated product is lanthanum oxalate crystallization.
Under Fig. 5 ultrasonication, the electromicroscopic photograph of oxalic acid inverted sequence precipitation yttrium gained oxide compound, shows that granular size is between 2-3 micron;
Under Fig. 6 ultrasonication, the XRD diffractogram of oxalic acid inverted sequence precipitation yttrium gained yttrium oxalate, shows its well-crystallized, is typical yttrium oxalate crystallization.
embodiment
embodiment 1 Yttrium Precipitated By Oxallc Acid+europium, inverted sequence, precipitation is than 1/1.6
(europium is 0.6%, (Y to get 50ml0.7324mol/L Yttrium trichloride+europium
2o
3+ Eu
2o
3)/REO>=99.999%) mixed liquor, feed liquid is contained in constant temperature to 80 ℃ in a small beaker, takes 7.38g H
2c
2o
42H
2o adds in the 500ml beaker that 200ml water is housed, and be placed in ultrasonic cleaning machine, regulating its temperature is 80 ℃, be heated to 80 ℃ of constant temperature, oxalic acid is dissolved completely, ultrasonic frequency is adjusted to 28KHz, with glass stick stirring and ultrasonication in the situation that, slowly in batches in oxalic acid solution, add Y+Eu feed liquid, control feed time about 5 minutes, adding mixed liquor stops ultrasonic afterwards immediately, gained is precipitated to mixed solution impouring to be equipped with in the 1000ml beaker of 400ml hot water, and be placed in 80 ℃ of still aging 1h of water, ageing 5h at normal temperatures subsequently, filtering and washing is to filtrate and AgNO
3till solution contact does not produce muddiness.Gained solid is dried yttrium oxalate europium at 40 ℃, with clean ceramic crucible at 900 ℃ in retort furnace calcination 1.5h obtain yttrium europium oxide.The burning mistake rate of calcination process is 63.51%, and in oxide compound, contained chlorine root is 46 ppm.As shown in Figure 1, granular size is 2 microns of left and right for the electromicroscopic photograph of yttrium europium oxide.The XRD diffractogram of yttrium oxalate europium is shown in Fig. 2, is the structure of typical yttrium oxalate.
Getting 50ml concentration is the 5N Lanthanum trichloride (La of 0.9975mol/L
2o
3/ REO>=99.999%) feed liquid, added in the 500ml beaker that 200ml water is housed for subsequent usely, take 12.1g oxalic acid H
2c
2o
42H
2o, adds in the 500ml beaker that 200ml water is housed.Above-mentioned two beakers are placed in to ultrasonic cleaning machine, and regulating its temperature is 80 ℃, is heated to 80 ℃ of constant temperature, and oxalic acid is dissolved completely.Ultrasonic frequency is adjusted to 28KHz, under glass stick stirring and ultrasonication, slowly in batches add oxalic acid solution toward being equipped with in the beaker of La feed liquid, control feed time about 5 minutes, add and stop immediately after oxalic acid ultrasonicly, the impouring of gained precipitated solid mixed solution is equipped with in the 1000ml beaker of 400ml hot water, afterwards this beaker is placed in to 80 ℃ of still aging 1h of water constant temperature, ageing 5h at normal temperatures afterwards, filtering and washing is to filtrate and AgNO
3till solution contact does not produce muddiness, gained solid is dried at 40 ℃, with clean ceramic crucible calcination 1.5h in retort furnace at 900 ℃.The burning mistake rate of calcination process is 54.82%, and in oxide compound, contained chlorine root is 20 ppm, 5.55 microns of the granularities of oxide compound, and its electromicroscopic photograph is shown in Fig. 3.Result shows that the chloride content in product is very low, and meta particle diameter is between 5-6 micron.Than the granularity of general precipitator method products therefrom (12-14 micron) almost little half, increase ultrasonic time, granularity can also further reduce.
embodiment 3 oxalic acid precipitation 5N lanthanums, synchronous, precipitation is than 1/1.6
Getting 50ml concentration is the 5N Lanthanum trichloride (La of 0.9975mol/L
2o
3/ REO>=99.999%) feed liquid, feed liquid is contained in a small beaker and is heated to 80 ℃.Take 12.1g oxalic acid H
2c
2o
42H
2o is for subsequent use.The 500ml beaker that 200ml water is housed is placed in to ultrasonic cleaning machine, and regulating its temperature is 80 ℃, is heated to 80 ℃ of constant temperature.Ultrasonic frequency is adjusted to 28KHz, under glass stick stirring and ultrasonication, slowly oxalic acid solid and the Lanthanum trichloride feed liquid that heated are joined in batches time and constant temperature 80 is housed spends in the 500ml beaker of 200ml water, control feed time about 5 minutes, adding oxalic acid stops ultrasonic afterwards immediately, the impouring of gained precipitated solid mixed solution is equipped with in the 1000ml beaker of 400ml hot water, afterwards this beaker is placed in to 80 ℃ of still aging 1h of water constant temperature, ageing 5h at normal temperatures afterwards, filtering and washing is to filtrate and AgNO
3till solution contact does not produce muddiness, gained solid is dried at 40 ℃, with clean ceramic crucible calcination 1.5h in retort furnace at 900 ℃.The burning mistake rate of calcination process is 52.62%, and in oxide compound, contained chlorine root is 16 ppm, and the granularity of oxide compound is 5.93 microns of D50=.Result shows that the chloride content in product is very low, and meta particle diameter is between 5-6 micron.Than the granularity of general precipitator method products therefrom (12-14 micron) almost little half, increase ultrasonic time, granularity can also further reduce.The XRD diffractogram of gained lanthanum oxalate is shown in Fig. 4, shows that precipitated product is lanthanum oxalate crystallization.
embodiment 4 oxalic acid precipitation 5N yttriums, inverted sequence, precipitation is than 1/1.6
Getting 50ml concentration is the 5N Yttrium trichloride (Y of 1.7822mol/L
2o
3/ REO>=99.999%) feed liquid, feed liquid is contained in a small beaker and is heated to 80 ℃.Take 17.96g H
2c
2o
42H
2o adds in the 500ml beaker that 200ml water is housed, and be placed in ultrasonic cleaning machine, regulating its temperature is 80 ℃, be heated to 80 ℃ of constant temperature, oxalic acid is dissolved completely, ultrasonic frequency is adjusted to 28KHz, with glass stick stirring and ultrasonication in the situation that, slowly in batches in oxalic acid solution, add Yttrium trichloride feed liquid, control feed time about 5 minutes, adding mixed liquor stops ultrasonic afterwards immediately, gained is precipitated to mixed solution impouring to be equipped with in the 1000ml beaker of 400ml hot water, and be placed in 80 ℃ of still aging 1h of water, ageing 5h at normal temperatures subsequently, filtering and washing is to filtrate and AgNO
3till solution contact does not produce muddiness.Gained solid is dried to obtain yttrium oxalate at 40 ℃, with clean ceramic crucible at 900 ℃ in retort furnace calcination 1.5h obtain yttrium oxide.The burning mistake rate of calcination process is 60.96%, and in oxide compound, contained chlorine root is 35 ppm, the granularity D50=1.86 micron of oxide compound, and its Electronic Speculum figure is shown in Fig. 5.The chloride content that shows products therefrom is very low, and granularity is also little, and 2 microns of left and right of meso-position radius are less many than the 4-6 micron of general precipitator method products therefrom.The XRD diffractogram of yttrium oxalate is shown in Fig. 6, shows its well-crystallized, is typical yttrium oxalate crystallization.
embodiment 5 oxalic acid precipitation 5N yttriums, synchronous, precipitation is than 1/1.6
Getting 50ml concentration is the 5N Yttrium trichloride (Y of 1.7822mol/L
2o
3/ REO>=99.999%) feed liquid, feed liquid is contained in a small beaker and is heated to 80 ℃.Take 17.96g H
2c
2o
42H
2o is for subsequent use, and the 500ml beaker that 200ml water is housed is placed in to ultrasonic cleaning machine, and regulating its temperature is 80 ℃, is heated to 80 ℃ of constant temperature.Ultrasonic frequency is adjusted to 28KHz, with glass stick stirring and ultrasonication in the situation that, slowly oxalic acid solid and the Yttrium trichloride feed liquid that heated are joined in batches time and constant temperature 80 is housed spends in the 500ml beaker of 200ml water, control feed time about 5 minutes, adding mixed liquor stops ultrasonic afterwards immediately, gained is precipitated to mixed solution impouring to be equipped with in the 1000ml beaker of 400ml hot water, and be placed in 80 ℃ of still aging 1h of water, ageing 5h at normal temperatures subsequently, filtering and washing is to filtrate and AgNO
3till solution contact does not produce muddiness.Gained solid is dried at 40 ℃, with clean ceramic crucible calcination 1.5h in retort furnace at 900 ℃.The burning mistake rate that records calcination process is 63.73%, contained chlorine root 150 ppm in oxide compound, the granularity D50=2.81um of oxide compound.The calcination process of the product of ultrasound precipitation burning mistake rate is not 60.11% under the same conditions, contained chlorine root 236 ppm in oxide compound, the granularity D50=6.80 micron result of oxide compound shows: the chloride content of ultrasonic lower precipitation products therefrom is lower, granularity is also less, between meso-position radius 2-3 micron, than the little 3-4 micron of the particle diameter of general precipitator method products therefrom.
embodiment 6 supersound washing rare earth oxalates (workshop precipitation 5N lanthanum, 5N yttrium, 4N cerium, neodymium and dysprosium gained)
Sample is precipitated as from certain company workshop and fetches, and in 500ml beaker, gets the various precipitations of 50ml volume, add 200ml water, put into afterwards ultrasonic device, under the frequency of 28KHz, the ultrasonic 15min of normal-temperature continuous, control experiment is not ultrasonic, afterwards respectively by its filtering and washing to filtrate and AgNO
3till solution contact does not produce muddiness.Gained solid is dried at 40 ℃, with clean ceramic crucible calcination 1.5h in retort furnace at 900 ℃, surveys it and burns mistake rate, contained chlorine root and the granularity of oxide compound in oxide compound.Result is as table 1.
The whether ultrasonic comparison to workshop deposit sample washing effect of table 1
| Product | Whether ultrasonic | Burn mistake rate/% | Oxide compound cl content/ppm | Oxide compound D50/ micron |
| 5N lanthanum trioxide | No | 54.81 | 12 | 13.36 |
| 5N lanthanum trioxide | Be | 55.13 | 14 | 14.04 |
| 5N yttrium oxide | No | 62.33 | 52 | 4.94 |
| 5N yttrium oxide | Be | 60.84 | 65 | 4.67 |
| 4N cerium oxide | No | 53.54 | 119 | 7.35 |
| 4N cerium oxide | Be | 52.51 | 75 | 8.17 |
| 2N5 Neodymium trioxide | No | 53.39 | 41 | 6.93 |
| 2N5 Neodymium trioxide | Be | 54.62 | 57 | 6.67 |
| 4N dysprosium oxide | No | 48.72 | 72 | 2.36 |
| 4N dysprosium oxide | Be | 49.88 | 44 | 4.1 |
Whether table 1 result shows: for ultrasonic for the chloride content in product and the not obvious effect that reduces of grain graininess in rare earth oxalate washing process.And, all many greatly than above-mentioned corresponding ultrasonic lower precipitation products obtained therefrom of the granularity of existing intermediate processing products therefrom.Prove only ultrasonicly in precipitation process, can play the chloride content that reduces in product and the effect of grain graininess.
Claims (2)
1. the auxiliary oxalate precipitation of ultrasonic wave is produced a low chlorine root fine granularity high purity rare earth compound, it is characterized in that:
[1] in precipitin reaction still pot, tank or groove, inject in advance oxalic acid solution, or the suspension that contains rare earth oxalate and dilute hydrochloric acid water, its volume can stir solution or suspension to be as the criterion with stirring arm, and the precipitation temperature control that makes solution temperature reach setting requires 1-100 ℃;
[2] under the precipitation temperature of setting, dissolve oxalic acid to saturated or approach saturation concentration, reinforced volume ratio according to rare earth with the ratio 1:1.5～1:1.8 of the amount of substance of oxalic acid and the densitometer equation in calculation acid solution of oxalic acid solution and rare earth feed liquid and rare earth feed liquid, calculate feed rate according to feed way and reaction times requirement, under hyperacoustic effect, complete charging reaction precipitation process; The temperature of rare earth feed liquid is the precipitation temperature scope that normal temperature arrives setting;
[3] after reinforced, can stop ultrasonic, ageing 1-6h after continuing to stir, or ultrasound precipitation slurry is proceeded to another reactor pot or groove carries out ageing 0.5-10h;
[4] after ageing, supernatant liquor is separated, precipitation continues to add water washing until can't detect the existence of chlorion in wash filtrate with silver nitrate solution;
[5] enter calcination process through the rare earth oxalate of washing and filtering dehydration, between 800-1400 ℃, calcine 1-6h, can obtain required low chlorine root fine granularity rare earth oxide.
2. the auxiliary oxalate precipitation of a kind of ultrasonic wave according to claim 1 is produced low chlorine root fine granularity high purity rare earth compound, it is characterized in that: described rare earth feed liquid is the one in Lanthanum trichloride feed liquid, Yttrium trichloride feed liquid, Yttrium trichloride+Europium trichloride mixed liquor.
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