CN110697775A - Preparation method of low-nitrogen niobium hydroxide - Google Patents
Preparation method of low-nitrogen niobium hydroxide Download PDFInfo
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Abstract
The invention provides a preparation method of low-nitrogen niobium hydroxide, which comprises the following steps of (1) neutralizing a niobium solution and ammonia water to obtain a niobium hydroxide solution, pumping the niobium hydroxide solution into a filter press for solid-liquid separation to obtain a niobium hydroxide precipitate, washing the niobium hydroxide precipitate with dilute ammonia water and pure water in sequence to obtain niobium hydroxide with the F content less than or equal to 5000ppm, (2) blow-drying the niobium hydroxide obtained in the step (1) with air to obtain a niobium hydroxide filter cake with the niobium pentoxide content of 45 ~ 55%, diluting concentrated hydrochloric acid into a dilute hydrochloric acid solution, and (3) adding the niobium hydroxide filter cake into the dilute hydrochloric acid solution, stirring for 20 ~ 40 minutes to obtain a mixed solution, putting the mixed solution into a filtration tank for filtration, adding the pure water into the filtration tank for stirring and pumping, drying, stirring and pumping for 3 times to obtain a precipitate, and drying the precipitate in a drying oven for 10 ~ 12 hours to obtain the low-nitrogen niobium hydroxide product, wherein the nitrogen content in the niobium hydroxide product can reach below 0.2%.
Description
Technical Field
The invention relates to a preparation method of low-nitrogen niobium hydroxide.
Background
The niobium hydroxide is generally prepared by neutralizing the niobium solution with aqueous ammonia in a precipitation tank to obtain Nb (OH)5Precipitating, pumping into a filter press for solid-liquid separation, washing with dilute ammonia water, filtering to remove Nb (OH)5Washing with pure water, and air-drying at 0.6 ~ 0.7MPa to obtain wet Nb (OH)5And putting the niobium hydroxide into a hot air circulation drying box to be dried to obtain the niobium hydroxide. Drying niobium hydroxide without hydrochloric acid treatment to obtain niobium hydroxide2O5The content is 72 ~When the content is 78%, the nitrogen content is not less than 3.5%, and the low nitrogen requirement cannot be met.
Chinese patent CN102465204A provides a method for preparing niobium pentoxide with high bulk density by soaking niobium hydroxide in concentrated hydrochloric acid, which mainly utilizes concentrated hydrochloric acid to change the niobium hydroxide system from alkaline to acidic, and increases the adsorption force between molecules, so niobium hydroxide molecules are more easily agglomerated at high temperature, and the density of niobium hydroxide per unit volume is increased, but concentrated hydrochloric acid has poor effect of reducing nitrogen content, and the content of residual chloride ions in the product is higher due to its higher concentration.
Disclosure of Invention
The invention aims to provide a preparation method of low-nitrogen niobium hydroxide, which can enable the nitrogen content in a niobium hydroxide product to reach below 0.2%.
In order to solve the technical problems, the technical scheme of the invention is as follows:
a preparation method of low-nitrogen niobium hydroxide comprises the following steps:
(1) neutralizing the niobium solution and ammonia water to obtain a niobium hydroxide solution, pumping the niobium hydroxide solution into a filter press to perform solid-liquid separation to obtain a niobium hydroxide precipitate, and washing the niobium hydroxide precipitate with dilute ammonia water and pure water in sequence to obtain niobium hydroxide with the F content less than or equal to 5000 ppm;
(2) blowing the niobium hydroxide obtained in the step (1) by air to obtain a niobium hydroxide filter cake with the niobium pentoxide content of 45 ~ 55%, and diluting concentrated hydrochloric acid into a dilute hydrochloric acid solution;
(3) adding the niobium hydroxide filter cake into a dilute hydrochloric acid solution, stirring for 20 ~ 40 minutes to obtain a mixed solution, putting the mixed solution into a filtering tank for filtering, adding pure water into the filtering tank for stirring, then pumping to dryness, repeating the stirring, pumping and drying for 3 times to obtain a precipitate, and drying the precipitate in a drying oven for 10 ~ 12 hours to obtain the low-nitrogen niobium hydroxide.
Further, in step (1) of the present invention, the niobium solution comprises the following components: nb2O5111.36g/L，Ta2O50.01g/L，W 0.005g/L，Si 0.006g/L，Fe 0.0015 g/L，H+5.34mol/L。
In step (1) of the present invention, the concentration of aqueous ammonia at the time of neutralization of the niobium solution and aqueous ammonia is 13.8mol/L, and the volume ratio of the niobium solution to aqueous ammonia is 1 (0.7 ~ 0.9).
Furthermore, in the step (1) of the invention, the concentration of dilute ammonia water when the niobium hydroxide is washed to remove fluorine by ammonia water is 3mol/L, and the proportion of the niobium hydroxide precipitate, the dilute ammonia water and the pure water is 1kg (65 ~ 75) L (8 ~ 12) L, wherein the mass of the niobium hydroxide precipitate is the mass of niobium pentoxide.
Further, in the step (2) of the present invention, the pressure of the air used for drying is 0.6 ~ 0.7.7 MPa.
Further, in the step (2) of the present invention, the mass fraction of the concentrated hydrochloric acid is 36%, and the volume concentration of the dilute hydrochloric acid solution is 1 ~ 2%.
Further, in the step (3) of the present invention, the ratio of the niobium hydroxide filter cake, the dilute hydrochloric acid solution and the pure water used for draining each time of the agitation washing is (145 ~ 155) kg:1000L: 100L.
Further, in the step (3) of the present invention, the drying temperature is 140 ~ 150 ℃.
Compared with the prior art, the invention has the following beneficial effects:
1. the method comprises the steps of soaking the niobium hydroxide in dilute hydrochloric acid, reacting hydrogen ions of the dilute hydrochloric acid with hydroxide ions ionized by the ammonia water to generate water, reacting the ammonia ions ionized by the ammonia water with chloride ions of the dilute hydrochloric acid to generate ammonium chloride, removing most of ammonium chloride through suction filtration, removing the residual chloride ions through pure water agitation washing, and simultaneously not bringing the ammonia ions into the product, so that the chloride ion content in the final niobium hydroxide product is below 3000ppm, and the nitrogen content is below 0.2%.
2. The niobium hydroxide is soaked by the hydrochloric acid, the hydrochloric acid concentration of the soaking solution is very low, redundant chloride ions are easy to wash away in the stirring and washing stage, and the process is easy to realize and popularize.
Detailed Description
The present invention will be described in detail with reference to specific embodiments, which are illustrative of the invention and are not to be construed as limiting the invention.
Example 1
The preparation method of the low-nitrogen niobium hydroxide comprises the following steps:
(1) the niobium hydroxide solution is obtained by neutralizing a niobium solution with a volume ratio of 1:0.8 and ammonia water with a concentration of 13.8mol/L, pumping the niobium hydroxide solution into a filter press for solid-liquid separation to obtain a niobium hydroxide precipitate, and washing the niobium hydroxide precipitate with dilute ammonia water with a concentration of 3mol/L and pure water in sequence to obtain niobium hydroxide with the F content less than or equal to 5000ppm, wherein the niobium solution comprises the following components: nb2O5111.36g/L，Ta2O50.01g/L，W 0.005g/L，Si 0.006g/L，Fe 0.0015 g/L，H+5.34mol/L, the concentration of the dilute ammonia water is 3mol/L, and the proportion of the niobium hydroxide precipitate (converted into niobium pentoxide), the dilute ammonia water and the pure water is 1kg:70L: 10L;
(2) blowing the niobium hydroxide obtained in the step (1) by using air with the pressure of 0.6MPa to obtain a niobium hydroxide filter cake with the niobium pentoxide content of 45 ~ 55%, and diluting concentrated hydrochloric acid with the mass fraction of 36% into a dilute hydrochloric acid solution with the volume concentration of 1.5%;
(3) adding the niobium hydroxide filter cake into a dilute hydrochloric acid solution, stirring for 30 minutes to obtain a mixed solution, putting the mixed solution into a suction filtration tank for suction filtration, adding pure water into the suction filtration tank, stirring, and then pumping to dry, repeating the stirring, the pumping and the drying for 3 times to obtain a precipitate, and drying the precipitate in a drying box at 150 ℃ for 10 hours to obtain the low-nitrogen niobium hydroxide, wherein the ratio of the niobium hydroxide filter cake to the dilute hydrochloric acid solution to the pure water used for the pumping and the drying by stirring each time is 150kg:1000L: 100L.
Example 2
The preparation method of the low-nitrogen niobium hydroxide comprises the following steps:
(1) neutralizing niobium solution with the volume ratio of 1:0.8 and ammonia water with the concentration of 13.8mol/L to obtain niobium hydroxide solution, pumping the niobium hydroxide solution into a filter press for solid-liquid separation to obtain niobium hydroxide precipitate, and washing the niobium hydroxide precipitate with dilute ammonia water with the concentration of 3mol/L and pure water in sequence to obtain the niobium hydroxide with the F content less than or equal to5000ppm of niobium hydroxide, wherein the niobium solution comprises the following components: nb2O5111.36g/L，Ta2O50.01g/L，W 0.005g/L，Si 0.006g/L，Fe 0.0015 g/L，H+5.34mol/L, the concentration of the dilute ammonia water is 3mol/L, and the proportion of the niobium hydroxide precipitate (converted into niobium pentoxide), the dilute ammonia water and the pure water is 1kg:70L: 10L;
(2) blowing the niobium hydroxide obtained in the step (1) by using air with the pressure of 0.6MPa to obtain a niobium hydroxide filter cake with the niobium pentoxide content of 45 ~ 55%, and diluting concentrated hydrochloric acid with the mass fraction of 36% into a dilute hydrochloric acid solution with the volume concentration of 1.5%;
(3) adding the niobium hydroxide filter cake into a dilute hydrochloric acid solution, stirring for 30 minutes to obtain a mixed solution, putting the mixed solution into a suction filtration tank for suction filtration, adding pure water into the suction filtration tank, stirring, and then pumping to dry, repeating the stirring, the pumping and the drying for 3 times to obtain a precipitate, and drying the precipitate in a drying box at 150 ℃ for 12 hours to obtain the low-nitrogen niobium hydroxide, wherein the ratio of the niobium hydroxide filter cake to the dilute hydrochloric acid solution to the pure water used for the pumping and the drying by stirring each time is 150kg:1000L: 100L.
Example 3
The preparation method of the low-nitrogen niobium hydroxide comprises the following steps:
(1) the niobium hydroxide solution is obtained by neutralizing a niobium solution with a volume ratio of 1:0.7 and ammonia water with a concentration of 13.8mol/L, pumping the niobium hydroxide solution into a filter press for solid-liquid separation to obtain a niobium hydroxide precipitate, and washing the niobium hydroxide precipitate with dilute ammonia water with a concentration of 3mol/L and pure water in sequence to obtain niobium hydroxide with the F content less than or equal to 5000ppm, wherein the niobium solution comprises the following components: nb2O5111.36g/L，Ta2O50.01g/L，W 0.005g/L，Si 0.006g/L，Fe 0.0015 g/L，H+5.34mol/L, the concentration of the dilute ammonia water is 3mol/L, and the proportion of the niobium hydroxide precipitate (converted into niobium pentoxide), the dilute ammonia water and the pure water is 1kg:65L: 8L;
(2) blowing the niobium hydroxide obtained in the step (1) by using air with the pressure of 0.7MPa to obtain a niobium hydroxide filter cake with the niobium pentoxide content of 45 ~ 55%, and diluting concentrated hydrochloric acid with the mass fraction of 36% into a dilute hydrochloric acid solution with the volume concentration of 1%;
(3) adding the niobium hydroxide filter cake into a dilute hydrochloric acid solution, stirring for 20 minutes to obtain a mixed solution, putting the mixed solution into a suction filtration tank for suction filtration, adding pure water into the suction filtration tank, stirring, and then pumping to dry, repeating the stirring, pumping and drying for 3 times to obtain a precipitate, and drying the precipitate in a drying box at 140 ℃ for 11 hours to obtain the low-nitrogen niobium hydroxide, wherein the ratio of the niobium hydroxide filter cake to the dilute hydrochloric acid solution to the pure water used for pumping and drying each stirring is 145kg:1000L: 100L.
Example 4
The preparation method of the low-nitrogen niobium hydroxide comprises the following steps:
(1) the niobium hydroxide solution is obtained by neutralizing a niobium solution with a volume ratio of 1:0.9 and ammonia water with a concentration of 13.8mol/L, pumping the niobium hydroxide solution into a filter press for solid-liquid separation to obtain a niobium hydroxide precipitate, and washing the niobium hydroxide precipitate with dilute ammonia water with a concentration of 3mol/L and pure water in sequence to obtain niobium hydroxide with the F content less than or equal to 5000ppm, wherein the niobium solution comprises the following components: nb2O5111.36g/L，Ta2O50.01g/L，W 0.005g/L，Si 0.006g/L，Fe 0.0015 g/L，H+5.34mol/L, the concentration of the dilute ammonia water is 3mol/L, and the proportion of the niobium hydroxide precipitate (converted into niobium pentoxide), the dilute ammonia water and the pure water is 1kg:75L: 12L;
(2) blowing the niobium hydroxide obtained in the step (1) by using air with the pressure of 0.7MPa to obtain a niobium hydroxide filter cake with the niobium pentoxide content of 45 ~ 55%, and diluting concentrated hydrochloric acid with the mass fraction of 36% into dilute hydrochloric acid solution with the volume concentration of 2%;
(3) adding the niobium hydroxide filter cake into a dilute hydrochloric acid solution, stirring for 40 minutes to obtain a mixed solution, putting the mixed solution into a suction filtration tank, carrying out suction filtration, adding pure water into the suction filtration tank, stirring, carrying out suction drying, repeating the stirring, the suction drying for 3 times to obtain a precipitate, and drying the precipitate in a drying box at 145 ℃ for 10 hours to obtain the low-nitrogen niobium hydroxide, wherein the ratio of the niobium hydroxide filter cake to the dilute hydrochloric acid solution to the pure water used for the suction drying by stirring each time is 155kg:1000L: 100L.
Comparative example: unlike example 1, step (2) did not include the step of diluting concentrated hydrochloric acid into a dilute hydrochloric acid solution, and the niobium hydroxide cake was stirred in concentrated hydrochloric acid in step (3).
Measurement of impurity content
The impurity contents of example 1 ~ 4 and comparative example were measured, and the results are shown in the following table, in which Nb is added2O5LOI content in ppm, the remaining impurity content in ppm:
| impurities | Example 1 | Example 2 | Example 3 | Example 4 | Comparative example 1 |
| Nb2O5 | 72.67 | 74.03 | 73.25 | 72.94 | 72.88 |
| N | 1800 | 1850 | 1870 | 1880 | 12690 |
| LOI | 26.77 | 25.41 | 26.22 | 26.45 | 24.93 |
| Ta | 56 | 60 | 58 | 59 | 61 |
| Fe | 36 | 39 | 38 | 40 | 37 |
| W | ＜10 | ＜10 | ＜10 | ＜10 | ＜10 |
| Si | ＜40 | ＜40 | ＜40 | ＜40 | ＜40 |
| Sb | 68 | 54 | 60 | 65 | 61 |
| Cl | 2700 | 2800 | 2840 | 2760 | 3650 |
As can be seen from the table, the chloride ion content of inventive example 1 ~ 4 is below 3000ppm, and the nitrogen content is below 0.2%, the chloride ion content of comparative example is as high as 3650ppm, and the nitrogen content is higher than 0.2%, which shows that the nitrogen content of niobium hydroxide product is not reduced as much as that of dilute hydrochloric acid, and more chloride ions are also brought in.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (8)
1. A preparation method of low-nitrogen niobium hydroxide is characterized by comprising the following steps: the method comprises the following steps:
(1) neutralizing the niobium solution and ammonia water to obtain a niobium hydroxide solution, pumping the niobium hydroxide solution into a filter press to perform solid-liquid separation to obtain a niobium hydroxide precipitate, and washing the niobium hydroxide precipitate with dilute ammonia water and pure water in sequence to obtain niobium hydroxide with the F content less than or equal to 5000 ppm;
(2) blowing the niobium hydroxide obtained in the step (1) by air to obtain a niobium hydroxide filter cake with the niobium pentoxide content of 45 ~ 55%, and diluting concentrated hydrochloric acid into a dilute hydrochloric acid solution;
(3) adding the niobium hydroxide filter cake into a dilute hydrochloric acid solution, stirring for 20 ~ 40 minutes to obtain a mixed solution, putting the mixed solution into a filtering tank for filtering, adding pure water into the filtering tank for stirring, then pumping to dryness, repeating the stirring, pumping and drying for 3 times to obtain a precipitate, and drying the precipitate in a drying oven for 10 ~ 12 hours to obtain the low-nitrogen niobium hydroxide.
2. The method for preparing niobium subhydroxide as claimed in claim 1, wherein: in the step (1), the niobium solution comprises the following components: nb2O5111.36g/L，Ta2O50.01g/L，W 0.005g/L，Si 0.006g/L，Fe0.0015 g/L，H+5.34mol/L。
3. The method for preparing a niobium hydroxide with low nitrogen content as claimed in claim 1, wherein in the step (1), the concentration of ammonia water is 13.8mol/L, and the volume ratio of the niobium solution to the ammonia water is 1 (0.7 ~ 0.9.9).
4. The method for preparing niobium subhydroxide as claimed in claim 1, wherein in step (1), the concentration of dilute ammonia water is 3mol/L, and the ratio of niobium hydroxide precipitate, dilute ammonia water and pure water is 1kg (65 ~ 75) L (8 ~ 12) L.
5. The method for preparing niobium subhydroxide as claimed in claim 1, wherein in the step (2), the pressure of air used for drying is 0.6 ~ 0.7.7 MPa.
6. The method for preparing niobium subhydroxide according to claim 1, wherein in the step (2), the mass fraction of the concentrated hydrochloric acid is 36%, and the volume concentration of the diluted hydrochloric acid solution is 1 ~ 2%.
7. The method for preparing niobium subhydroxide according to claim 1, wherein in the step (3), the ratio of the niobium hydroxide filter cake, the dilute hydrochloric acid solution and the pure water used for pumping out each time of stirring and washing is (145 ~ 155) kg:1000L: 100L.
8. The method for preparing niobium subhydroxide as claimed in claim 1, wherein the drying temperature in step (3) is 140 ~ 150 ℃.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113526553A (en) * | 2021-08-30 | 2021-10-22 | 南京弘顺和生物科技有限公司 | Preparation method and production equipment of superfine niobium hydroxide |
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