JPH0325490B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Technical field The present invention relates to a method for separately recovering molybdenum, uranium, and vanadium, which are rare metals, from their coexisting substances (for example, ores or chemical precipitates). (b) Background Art Naturally occurring molybdenum and uranium ores often contain molybdenum, uranium, and vanadium, although the amounts vary. However, the molybdenum, uranium, and
Currently, there are no reports on industrial separate recovery methods for vanadium. Generally, coexisting molybdenum, uranium, and vanadium are leached out, and molybdenum, uranium, and vanadium are extracted from the leachate.
Co-precipitation, foaming separation, adsorption, and solvent extraction methods are known for the separate recovery of vanadium.These methods are very often used to separate rare metals, but molybdenum, uranium, vanadium The forms of are M ₀ (~valence), U (~valence), V (
~ V valence) and have similar properties,
Precipitation separation by direct neutralization is difficult. When a coexistence of molybdenum, uranium, and vanadium is leached with sulfuric acid and neutralized by adding an alkaline agent to the leachate, uranium precipitates almost completely at pH 6, but vanadium also begins to precipitate slightly at pH 4. Molybdenum hardly precipitates, but when molybdenum concentrations are high, there is considerable contamination. Furthermore, in a reduced state, molybdenum, uranium, and vanadium all precipitate, making separation difficult. Chemicals added for uranium co-precipitation include ferric salts such as ferric chloride or ferric ammonium sulfate, and aluminum salts such as aluminum sulfate or aluminum phosphate. However, in both cases, molybdenum and vanadium may precipitate due to pH adjustment, which is not appropriate. Furthermore, as a foaming separation method, foaming separation of uranium in seawater was attempted using surfactants such as soda soap, sodium lauryl sulfate, and laurylamine acetic acid.
Uranium adsorption with iron, ferric oxide, iron sulfide, titanium compounds, or various metal soaps as organic absorbents has also been reported, but none of them can be applied to solutions containing molybdenum, uranium, or vanadium acidic with sulfuric acid. difficult. Therefore, it is difficult to separate and recover the above-mentioned three-component mixture, and there is currently no effective method, so it is necessary to find another separation method. (C) Disclosure of the Invention As a result of various studies, the present inventor discovered a method for separately recovering molybdenum, uranium, and vanadium dissolved in mineral acid leachate such as sulfuric acid. , which makes it possible to recover vanadium as a single raw material or product. That is, the present invention performs mineral acid leaching of coexisting molybdenum, uranium, and vanadium such as ores or chemical precipitates, and removes molybdenum, uranium, and vanadium dissolved in the leachate.
Among vanadium, molybdenum is first adsorbed and removed by chelate resin, then uranium is separated from vanadium using resin, and molybdenum, uranium,
The purpose of the present invention is to provide a method for separately recovering vanadium. (b) A second step in which the obtained leachate is brought into contact with a chelating ion exchange resin. (c) An alkaline agent is added to the liquid obtained by passing the liquid in the second step, and the pH is adjusted to 0. 5-3 preferably PH1-2,
If solid content is generated, the third step is to separate solid and liquid; (d) the fourth step is to contact the liquid obtained in the third step with an ion exchange resin; (e) the liquid obtained by passing the liquid in the fourth step. A fifth step of adding an alkaline agent to the liquid to adjust the pH to 6 to 9, preferably 6 to 7, and recovering vanadium by solid-liquid separation of the generated precipitate. 6th step of elution using an acid or alkaline solution, (g) Add alkali or acid to the solution eluted in the 6th step, adjust the pH to 8-10, separate the formed precipitate into solid and liquid, and recover molybdenum. (h) an eighth step in which the adsorbates on the resin in the fourth step are eluted with an alkaline salt solution; (i) in the solution eluted in the eighth step (if carbonate ions are present, mineral acid The ninth step consists of adjusting the pH to 6 or higher with an alkaline agent (after making it acidic by adding alkali), and separating the resulting precipitate into solid-liquid to recover uranium. The details of the present invention will be explained below. [About the first step] In this step of leaching crushed ore or chemical precipitates that coexist with molybdenum, uranium, and vanadium, sulfuric acid, which is common and inexpensive, is used as the mineral acid, and the free sulfuric acid in the solution after leaching is used. The concentration
Perform one-stage leaching at room temperature and pressure to reduce the amount from 50g/ to 100g/. Furthermore, precipitation of gypsum due to calcium contained in the coexisting materials and undissolved residues are removed, and if necessary, gypsum can be recovered by flotation. Furthermore, if trivalent iron ions are present in the leachate, it is preferable to perform a treatment to reduce them to divalent iron ions using a reducing agent such as sulfur dioxide gas or sodium bisulfite. [Regarding the second step] The leachate obtained in the first step is brought into contact with a chelating ion exchange resin to adsorb molybdenum. In this case, it is desirable to appropriately adjust the acid concentration of the liquid. The relationship between free sulfuric acid concentration and molybdenum adsorption curve is shown in FIG. When the leachate is an acidic sulfuric acid solution, it is preferable that the free sulfuric acid concentration is 50 to 100 g/l.
It is advantageous in actual operation that a leachate having such a free sulfuric acid concentration is obtained in the previous leaching treatment of the smelting intermediate. Examples of chelating ion exchange resins that can be used in the present invention include the following commercially available resins. For example, a chelating ion exchange resin having an aminocarboxylic acid group as a functional group has the general formula (In the formula, M represents an alkali metal atom or a hydrogen atom, and R ₁ and R ₂ each represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.) The compound, phenol, and aldehyde are crosslinked into three dimensions. can get. This resin is known to be able to reduce the iron ion concentration in an acidic electrogalvanizing bath, according to Japanese Patent Application Laid-Open No. 121241/1983. Commercially available chelating ion exchange resins having aminocarboxylic acid groups that can be used in the present invention include the trade name Yuselek UR-10 and the same.
UR-20, UR-30, UR-40 and UR-50,
Examples include Sumikilate Q-18HR and MC-30, Amberlite IRC-718, and Diaion CR-10. In addition, as a chelating ion exchange resin having an aminoalkyl phosphate group as a functional group, for example, commercially available Sumikylate KA-850 and Diaion CR-20
Furthermore, as a chelating ion exchange resin having a pyridine group as a functional group, for example, Sumikylate CK
-2 and the like can also be used in the practice of the present invention. A convenient method for bringing the chelating ion exchange resin into contact with the leachate is to pass the leachate through a column filled with resin. At that time, it is preferable to pass the liquid so that the liquid passing rate (space velocity SV) is 5.0 or less. In addition, the contact temperature of the leachate to the resin is as follows:
A temperature of 10 to 30°C is appropriate. Thereby, only molybdenum in the leachate can be selectively adsorbed onto the resin while substantially all of the elements other than molybdenum remain in the leachate. Figure 2 shows an acidic sulfuric acid solution containing molybdenum, uranium, and vanadium (free sulfuric acid concentration approximately 50g/)
After reducing trivalent iron ions to divalent ones by blowing in sulfur dioxide gas, the amount of liquid passed through a column packed with the chelating ion exchange resin of Uniselect UR-50 at a space velocity of SV = 1. This figure shows the relationship between the flow-through point and the flow-through point, and it can be seen that only molybdenum is selectively adsorbed to the resin from this solution under predetermined conditions. [About the third step] Add alkali agents such as calcium carbonate and slaked lime to the tail liquid obtained by passing the liquid in the second step, and adjust the pH to 0.5 to 3.
Preferably, it is neutralized to pH 1 to 2, and if gypsum precipitates, solid-liquid separation is performed. [Regarding the fourth step] Uranium and vanadium are present in the liquid obtained in the third step, and if vanadium is pentavalent, it is necessary to reduce vanadium in order to adsorb uranium to the resin. In the second step, when reducing with SO ₂ , there is no particular need to reduce again, but if necessary, a reducing agent is added. As the ion exchange resin, an anion exchange resin, preferably a strongly basic anion exchange resin, is used. Since an anion exchange resin is used, most divalent cations such as calcium and sodium are not adsorbed, which is very advantageous in increasing the purity of recovered uranium. The adsorption reaction of uranium by a strongly basic anion exchange resin is as follows. UO ₂ (SO ₄ ) ₃ ^4- +4R ⁺ X ^- R ₄ ⁺ UO ₂ (SO ₄ ) ₃ ^4- + ^4X -Also, a small portion reacts as follows. UO ₂ (SO ₄ ) ₂ ^4- +2R ⁺ X ^- R ₂ ⁺ UO ₂ (SO ₄ ) ₂ ^4- +2X ^- (R ⁺ is quaternary amine resin, X is NO ₃ ^- ,
Cl ^- , HSO ₄ ^- , 1/2SO ₄ ^2- ) Uranium is adsorbed onto anion exchange resin regardless of its valence. In addition, uranium adsorption is 100% better at a pH of 0.5 to 3, preferably at a pH of 1 to 2, than in a strongly acidic environment. If the pH is 3 or higher, vanadium and uranium will precipitate, so this step is operated at a pH of 0.5 to 3. The resin is an anion exchange resin, preferably a strongly basic anion exchange resin as SO ₄ type, and
Use for cleaning with H ₂ SO ₄ 5g/. [About the 5th step] The liquid that passed through the resin in the 4th step contains vanadium containing sky blue vanadium ions (VO ²⁺ or
Vanadium is present as VO(OH) ₂ and V(OH) ₃ by adding an alkali agent at ^a pH of 6 to 9, preferably 6 to 7, and is separated and recovered. Since this precipitate contains divalent cations that are not adsorbed to the resin, further purification is required, but the recovered vanadium hydroxide can be calcined to produce a product as vanadium pentoxide. [Regarding the 6th step] The molybdenum adsorbed on the resin in the above-mentioned 2nd step can be eluted with acid or alkali. Hydrochloric acid or sulfuric acid can be used as the acid, and molybdenum can be effectively eluted if the acid concentration is 2N or higher, and a caustic soda solution or aqueous ammonia can be used as the alkali, and if the concentration is 1N or higher, molybdenum can be effectively eluted. During elution, the higher the concentration of acid or alkali, the smaller the amount of eluent is required, and the molybdenum solution with higher concentration can be recovered. [Regarding the 7th step] The molybdenum eluted with acid or alkali in the 6th step can be recovered as a precipitate by neutralizing with an alkali or acid in a conventional manner. Furthermore, when the eluent is an acid, it is also possible to blow in hydrogen sulfide or the like and recover it as a sulfide. [About the 8th step] Elution of uranium adsorbed to the ion exchange resin is normal.
A 1M alkali sulfate solution or a 1M alkali chloride solution is used. The reaction is as follows. R ₄ UO ₂ (SO ₄ ) ₃ +4X ^- 4RX+UO ₂ ^2- +3SO ₄ (where X=NO ₃ ^- or Cl ^- ) The adsorbed uranium is eluted as shown in the above reaction formula. Therefore, in the fourth step, uranium adsorbed on the resin is eluted using, for example, a 1M sodium chloride solution. At this time, if sodium carbonate is used, uranium can be eluted in a short time and is effective for concentrating and separating uranium. [Regarding the 9th step] If the uranium solution eluted in the 8th step has carbonate groups, it will form a uranyl carbonate complex by adding an alkali agent and will not completely precipitate. Therefore, the uranium solution eluted in the 8th step will have a pH of 3 or lower using hydrochloric acid as a mineral acid. Remove carbonate roots as Next, an alkaline agent is added to raise the pH to 6 or higher, and the uranate is recovered as a uranate. At this time, in addition to sodium hydroxide, aqueous ammonia and calcium hydroxide can be used as the alkaline agent. The precipitation form of uranium is U ₃ O ₈ at pH 6 to 7.
(OH) ₂ , Na ₂ U ₂ O ₂₂ at PH9.6, Na ₅ U ₇ O ₂₄ at PH10
Therefore, it can be collected separately at pH 6 or higher. Uranate precipitation can occur at a pH of 6 or above, but as seen in the above-mentioned different forms of PH, in order to obtain U ₃ O ₈ (OH) ₂ , which is the desired precipitation form, a pH of 7 to 7 is required.
It is preferred to precipitate at 8. As described above, the present invention is an extremely useful method that allows Mo, U, and V to be separately recovered and manufactured into products more efficiently than the coexisting materials of Mo, U, and V. (d) Example A chemical precipitate containing molybdenum, uranium, vanadium, etc. having the composition shown in Table 1 was treated.

[Table] First, 500 g of the above chemical precipitate was added to Solution 5 with a sulfuric acid concentration of 105 g/ml, and leaching was performed at room temperature for 1 hour. The composition of the leachate is shown in Table 2, and the composition of the leach residue is shown in Table 3.

【table】

[Table] Next, the obtained leachate was reduced by blowing sulfur dioxide gas as shown in Table 2, and then passed through the chelate resin. The composition of the tail liquid that has passed through the chelate resin is
Shown in the table.

[Table] Adsorbed molybdenum is eluted with a weak acid and can be completely separated and recovered from other elements. Calcium carbonate was added as an alkaline agent to the extracted tail liquid shown in Table 4, the pH was set to 1.5, gypsum was separated, and the liquid was passed through a strongly basic anion exchange resin to adsorb uranium. The composition is shown in Table 5.

[Table] Next, add an alkaline agent to the liquid that has passed through the resin and adjust the pH.
Table 6 shows the composition of the solution obtained by making a precipitate as Nos. 6 to 7, and Table 7 shows the composition of the precipitate.

【table】

[Table] U adsorbed on the resin was eluted with sodium carbonate, and hydrochloric acid was added to the eluent to adjust the pH to 2.5 to remove carbonate radicals, and then the pH was adjusted to 7 using sodium hydroxide to form uranate precipitates. Ta. The composition of the precipitate is shown in Table 8.

[Table] (E) Effects of the Invention As described above, according to the present invention, molybdenum, uranium, and vanadium can be efficiently recovered and concentrated as precipitates from coexisting materials of molybdenum, uranium, and vanadium. Each metal can be recovered from the precipitate at low cost.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between free sulfuric acid concentration and molybdenum adsorption curve, Figure 2 is a graph showing the relationship between the flow rate and flow point when leachate is passed through a chelating ion exchange resin, and Figure 3 The figure is a flow sheet showing an example of the method of the present invention.

Claims (1)

[Claims] 1. A first step of leaching a substance containing molybdenum, uranium, and vanadium using a mineral acid and then separating it into solid and liquid; and a liquid and ions obtained by solid-liquid separation in the first step. a second step of bringing it into contact with the exchange resin;
A third step in which the liquid after contacting with the ion exchange resin in the second step is adjusted to pH 0.5 to 3 with an alkaline agent, and a fourth step in which the liquid obtained in the third step is brought into contact with the ion exchange resin. A fifth step of adjusting the pH of the liquid after contact with the ion exchange resin in the fourth step to 6 to 9 with an alkaline agent and recovering vanadium through solid-liquid separation;
The sixth step is to elute the adsorbed matter of the ion exchange resin after contact with the liquid in the second step using an acid or alkaline solution.
step, a seventh step in which the liquid eluted in the sixth step is adjusted to pH 8 to 10 with an acid or alkaline agent, and solid-liquid separation is performed to recover molybdenum, and the ion exchange resin after contact with the liquid in the fourth step is The 8th step consists of eluting the adsorbate using an alkaline salt solution, and the 9th step consists of adjusting the eluted solution in the 8th step to pH 6 or higher using an alkaline agent and performing solid-liquid separation to recover uranium. A method for separating and collecting rare metals. 2. The method for separate recovery of rare metals according to claim 1, wherein the mineral acid used in the first step is sulfuric acid, and the sulfuric acid concentration is 50 to 100 g/l in the leached solution. 3. The method for fractional recovery of rare metals according to claim 1 or 2, wherein the ion exchange resin in the second step is a chelating ion exchange resin. 4. The method for separating and recovering rare metals according to claim 1, 2, or 3, wherein the alkaline agent in the third step is calcium carbonate. 5. The method for separating and recovering rare metals according to claim 1, 2, 3, or 4, wherein the ion exchange resin in the fourth step is an anion exchange resin. 6. Claims 1 and 2, wherein the alkaline agent in the fifth step is at least one of sodium hydroxide, calcium carbonate, and calcium hydroxide.
A method for separating and collecting rare metals as described in Section 3, Section 3, Section 4, or Section 5. 7. Claims 1, 2, 3, 4, 5, or 6, wherein the acid used in the six steps is hydrochloric acid or sulfuric acid, and the alkali agent is caustic soda or aqueous ammonia. Separate collection method for rare metals as described in section. 8. Claims 1, 2, 3, 4, and 5, wherein the acid used in the seventh step is hydrochloric acid or sulfuric acid, and the alkali agent is caustic soda.
A method for separating and collecting rare metals as described in paragraph 6 or 7. 9 Claims 1, 2, 3, 4, 5, 6, 7 or 9, wherein the alkali salt used in the eighth step is sodium chloride or sodium carbonate. Separate collection method for rare metals as described in Section 8. 10 Claims 1, 2, and 3, wherein the alkaline agent used in the ninth step is sodium hydroxide, aqueous ammonia, or calcium hydroxide.
A method for separating and recovering rare metals as described in paragraph 1, paragraph 4, paragraph 5, paragraph 6, paragraph 7, paragraph 8, or paragraph 9.