JP4322057B2 - Recovery of ammonium complex of metal fluoride and method of reuse - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a method for recovering an inorganic complex of metal fluoride and an ammonium salt from an ammonium complex of metal fluoride, and further effectively reusing them if necessary. A method of converting an ammonium complex of metal fluoride, which has been discarded as waste, into an inorganic complex of metal fluoride and recovering it as a reusable form, and simultaneously reusing these by-product ammonium salts About.
[0002]
[Prior art]
Ammonium complexes of metal fluoride are mainly generated during the surface treatment of aluminum or its alloys, and these complexes can hardly be reused as they are and are usually treated as industrial waste as they are. It had been.
[0003]
An example of the treatment of aluminum or its alloy by-produced by the metal fluoride ammonium complex is as follows.
[0004]
(A) A treatment method in which an aluminum material is immersed in an aqueous solution of ammonium hydrogen fluoride (acidic ammonium fluoride) containing a Cu compound and / or an Ag compound. At this time, the Cu compound is preferably basic copper carbonate and the Ag compound is preferably silver nitrate.
[0005]
(B) Various surface treatments have been developed as a method for adding a function to the surface of aluminum. For example, there is a chemical conversion treatment described in JP-A-2001-11648. This heats a treatment liquid containing magnesium silicofluoride (MgSiF ₆ .6H ₂ O) and ammonium silicofluoride ((NH ₄ ) ₂ SiF ₆ ). By immersing aluminum parts in a heated aqueous solution, a mixture of NH ₄ MgAlF ₆ and MgAlF ₅ .1.5H ₂ O or a mixture of NH ₄ MgAlF ₆ and MgAl ₂ F ₈ .2H ₂ O is applied to the aluminum surface. The specific compound film is formed. When a treatment liquid containing magnesium silicofluoride and ammonium silicofluoride is heated to 70 ° C. or higher, both components are hydrolyzed and magnesium ions, ammonium ions, fluorine ions, hydrofluoric acid, silicic acid, etc. coexist. .
[0006]
In any case, in the surface treatment of each aluminum or its alloy shown above, an ammonium complex of metal fluoride is formed.
[0007]
[Problems to be solved by the present invention]
The problem to be solved by the present invention is to recover the above-mentioned metal fluoride ammonium complex, which has not been developed yet, by converting it into a reusable compound, and if necessary, recovering it. It is to provide a means for reusing etc.
[0008]
[Means for Solving the Problems]
This means, the ammonium complex of the resulting metal fluoride as industrial waste and inorganic salts (R-X) by reaction, forms an inorganic complexes and ammonium salts of the metal fluoride, is recovered in this form Further, it can be solved by reusing them as necessary.
R is a cation of the upper-inorganic salt (R-X), and X represents an anion.
However, the ammonium complex of the metal fluoride is at least one of ammonium fluoride (NH ₄ ) _y MF _z containing at least one metal M of Al, Fe and Si (provided that y = 1, 2 or 3) Any one and z = 4, 5, 6 or 7).
The cation (R) of the inorganic salt is at least one of Na and K.
[0009]
[Effects of the Invention]
Regarding the reaction of the metal fluoride ammonium complex of the present invention with an inorganic salt, (NH ₄ ) ₃ AlF ₆ is used as an example of the former metal fluoride ammonium complex, and Na ₂ SO ₄ is used as a representative example of the latter inorganic salt. The chemical formula is as follows.
[0010]
2 (NH ₄ ) ₃ AlF ₆ + 3Na ₂ SO ₄ → 2Na ₃ AlF ₆ +3 (NH ₄ ) ₂ SO ₄
[0011]
As the ammonium complex of metal fluoride used in the present invention, those produced as a by-product in the surface treatment process of aluminum or its alloy are widely used.
[0013]
As the inorganic salt used in the present invention, various salts represented by R—X can be widely used. Here, R represents a cation, X is denotes an anion, specifically as R, is N a, K.
[0014]
X represents an anion. Specifically, Cl, SO ₄ , F, CO ₃ , HCO ₃ , NO ₃ , PO _{4 and the} like can be exemplified, and particularly preferable examples include Cl and SO ₄ .
[0015]
The conditions for the above reaction of the present invention will be described in detail below.
(A) The amount of water during the reaction The amount necessary for dissolving the inorganic salt (RX) or the amount necessary for ionizing the inorganic salt (RX) is preferred. In this respect, the amount of water is preferably large, but 100 to 100,000 parts by weight, particularly preferably 100 to 10,000 parts by weight of water is used with respect to 100 parts by weight of the inorganic salt (RX). However, if the amount of water becomes too large, the amount of water produced by the separation step of the recovered metal fluoride with the inorganic complex increases, so the yield of recovered ammonium salt decreases.
[0016]
The amount of water used for washing is not particularly limited, but for the same reason, it is 100 to 100,000 parts by weight, particularly preferably 100 to 10,000 parts by weight based on 100 parts by weight of the recovered metal fluoride inorganic complex. It is good to use the water of the part.
[0017]
(B) pH during reaction
The pH during the reaction is usually 5-9. Under strong acidity or strong alkalinity, the ammonium complex of metal fluoride tends to decompose and generate ammonia gas. Therefore, the reaction is particularly preferably near neutral (pH 6-8).
[0018]
(C) Mixing order After the inorganic salt (RX) is completely dissolved, it may be reacted with an ammonium complex of a metal fluoride. Moreover, you may mix in the state which does not melt | dissolve completely.
[0019]
(D) Addition method Since the metal fluoride ammonium complex is hardly soluble in water, the metal fluoride ammonium complex may be added as a solid, or an aqueous dispersion of the metal fluoride ammonium complex is prepared in advance. This may be added. The ammonium complex of metal fluoride may be added to the inorganic salt (RX) solution at the same time, or one of them may be added first, and the other may be added after a while.
[0020]
(E) Amount of inorganic salt (RX) The amount of inorganic salt (RX) required to make the ammonium in the ammonium complex of the metal fluoride inorganic, and efficiently used as an insoluble residue The inorganic complex is recovered. In this case, the inorganic salt (R-X) is preferably 10 to 1000 parts by weight with respect to 100 parts by weight of the metal fluoride ammonium complex, but in order to recover the high-purity metal fluoride inorganic complex, -200 parts by weight are particularly preferred.
[0021]
(F) Particle size The particle size of the inorganic complex of metal fluoride is not particularly limited. However, those having a large particle size are preferred from the viewpoint of filtration and dehydration. Furthermore, there is no problem in preparing the particle size with the polymer flocculant. As the polymer flocculant in this case, any conventionally known polymer flocculants can be used, and representative examples thereof include polyacrylamide flocculants, polymethacrylate ester flocculants, polyacrylic acid soda flocculants, polyamine flocculants. It is possible to use a flocculant, an amino condensation flocculant, and the like. The amount of use may be 5 to 20 ppm with respect to the amount of water.
[0022]
(G) The water temperature at the time of temperature dissolution, reaction, and washing is preferably 15 ° C. or higher that can be handled at room temperature. Even if it is dissolved at a very low temperature, the effect is poor and the recovery rate of the metal fluoride inorganic complex is lowered. Accordingly, the temperature during dissolution, reaction, and washing is 15 to 100 ° C, preferably 25 to 90 ° C.
[0023]
(H) The reaction time of the metal fluoride ammonium complex and the inorganic salt (RX) is not particularly limited, but is preferably about 0.01 to 48 hours. However, 0.01 to 12 hours are particularly preferable industrially. The reaction between the metal fluoride ammonium complex and the inorganic salt (R-X) may be performed under normal pressure or under vacuum.
[0024]
The inorganic complex of metal fluoride thus obtained (recovered) is dispersed again in water and washed. In order to increase the purity, the washing operation may be repeated.
[0025]
The recovered inorganic complex of metal fluoride can be reused as a flux for electrolytic refining, a flux for plating, an emulsion, and the like. Ammonium salts can be reused as fertilizers and industrial products. Further, when F is used as the anion of the inorganic salt (R—X), ammonium fluoride (NH ₄ F) is regenerated, so that it can be used again for the surface treatment process. In this case, hydrofluoric acid may be added and used.
[0026]
【Example】
The present invention will be described more specifically with reference to typical examples of the present invention. These are merely examples for explanation, and the present invention is not limited to these.
Evaluation in the examples was performed by the following methods (1) to (4).
(1) Metal impurity amount: evaluated by inductively coupled plasma atomic emission spectrometry.
(2) Particle size: Evaluated by a particle size distribution meter (laser diffraction / scattering method).
(3) Ammonia content: evaluated by titration.
(4) Crystal structure analysis: evaluated by X-ray diffractometer (XRD).
[0027]
[Example 1]
The amount of impurities in (NH ₄ ) ₃ AlF ₆ produced as industrial waste was Ca: 20 ppm, Cu: 50 ppm, Fe: 150 ppm, Mg: 850 ppm, Mn: 20 ppm, Na: 100 ppm, Si <500 ppm.
[0028]
243 g of (NH ₄ ) ₃ AlF ₆ produced as the industrial waste was measured and dispersed in 2.5 kg of water. Thereafter, 230 g of NaCl was added, followed by stirring at 90 ° C. for 6 hours. The pH of the solution was 7.2. Thereafter, the solution was cooled to 40 ° C. and then separated into a precipitate and a reaction filtrate by suction filtration.
[0029]
The collected precipitate was dispersed in 1 kg of water at 40 ° C., washed with the precipitate, then separated into a precipitate and a washing filtrate by filtration, and the precipitate was dried at 105 ° C. for 6 hours.
[0030]
Furthermore, the reaction filtrate was concentrated at 130 ° C. for 4 hours. The concentrate was cooled to 25 ° C. to precipitate crystals. The crystals and the filtrate were separated by filtration, and the crystals were dried at 105 ° C. for 6 hours.
The weight of the obtained precipitate was 261 g. Moreover, the crystal weight obtained from the liquid which concentrated the filtrate was 203g.
The average particle size of the obtained precipitate was 1.8 μm.
[0031]
Further, as a result of XRD analysis of the precipitate and the crystal, the precipitate was assigned to Na ₃ AlF ₆ and the crystal was assigned to NH ₄ Cl. The ammonia content in Na ₃ AlF ₆ was 0.02%, and other impurities were Ca <5 ppm, Cu <5 ppm, Fe <5 ppm, Mg <5 ppm, Mn <1 ppm, Si <10 ppm. Furthermore, Na in NH ₄ Cl; 0.05%, and it was confirmed that the reaction had progressed quantitatively (99.7%). Impurities were Ca <5 ppm, Cu <5 ppm, Fe <5 ppm, Mg <5 ppm, Mn <1 ppm, Si <10 ppm.
[0032]
[Example 2]
The amount of impurities in (NH ₄ ) ₂ SiF ₆ produced as industrial waste was Ca: 30 ppm, Cu: 20 ppm, Fe: 100 ppm, Mg: 500 ppm, Mn: 100 ppm, Na: 50 ppm.
[0033]
831 g of (NH ₄ ) ₂ SiF ₆ produced as the industrial waste was measured, and 730 g of KCl was added. Thereafter, 8 kg of water was added and the mixture was stirred at 30 ° C. for 12 hours. The pH of the solution was 7.1. The precipitate and the reaction filtrate were separated by suction filtration.
[0034]
The collected precipitate was dispersed in 5 kg of water at 30 ° C., and the precipitate was washed, and then separated into a precipitate and a washing filtrate by filtration, and the precipitate was dried at 105 ° C. for 8 hours.
[0035]
Furthermore, the reaction filtrate was concentrated at 130 ° C. for 13 hours. The concentrate was cooled to 25 ° C. to precipitate crystals. The crystals and the filtrate were separated by filtration, and the crystals were dried at 105 ° C. for 5 hours.
[0036]
The weight of the obtained precipitate was 1.03 kg. Moreover, the crystal weight obtained from the liquid which concentrated the filtrate was 505g.
The average particle size of the obtained precipitate was 2.5 μm.
[0037]
As a result of XRD analysis of the precipitate and the crystal, the precipitate was assigned to K ₂ SiF ₆ and the crystal was assigned to NH ₄ Cl. The ammonia content of K ₂ SiF ₆ was 0.05%, and other impurities were Ca <5 ppm, Cu <5 ppm, Fe <5 ppm, Mg <5 ppm, Mn <1 ppm, Na <5 ppm. Furthermore, K in NH ₄ Cl; 0.1%, and it was confirmed that the reaction proceeded almost quantitatively (98.9%). As impurities, Ca <5 ppm, Cu <5 ppm, Fe <5 ppm, Mg <5 ppm, Mn <1 ppm, Si <10 ppm, Na <5 ppm.
[0038]
[Example 3]
The amount of impurities in (NH ₄ ) FeF ₆ produced as industrial waste was Ca: 100 ppm, Cu: 40 ppm, Mg: 900 ppm, Mn: 20 ppm, Na: 200 ppm, Si: 400 ppm.
[0039]
Na ₂ SO ₄ 500 g was measured and dissolved in 10 kg of water. To this, 500 g of (NH ₄ ) FeF ₆ produced as industrial waste was added. Thereafter, 500 g of Na ₂ SO ₄ was added, followed by stirring at 70 ° C. for 12 hours. The pH of the solution was 7.1. Thereafter, the solution was cooled to 40 ° C. and then separated into a precipitate and a reaction filtrate by suction filtration.
[0040]
The collected precipitate was dispersed in 2 kg of water at 50 ° C., washed the precipitate, then separated by filtration into a precipitate and a washing filtrate, and the precipitate was dried at 105 ° C. for 6 hours.
Furthermore, the reaction filtrate was concentrated at 130 ° C. for 18 hours. The concentrate was cooled to 25 ° C. to precipitate crystals. The crystals and the filtrate were separated by filtration, and the crystals were dried at 105 ° C. for 8 hours.
[0041]
The weight of the obtained precipitate was 350 g. Moreover, the crystal weight obtained from the liquid which concentrated the filtrate was 440g.
The average particle size of the obtained precipitate was 2.5 μm.
[0042]
As a result of further XRD analysis of the precipitate and the crystal, the precipitate was assigned to Na ₃ FeF ₆ and the crystal was assigned to (NH ₄ ) ₂ SO ₄ . The ammonia content of Na ₃ FeF ₆ was 0.03%, and other impurities were Ca <5 ppm, Cu <5 ppm, Mg <5 ppm, Mn <1 ppm, and Si <10 ppm. Further, Na in (NH ₄ ) ₂ SO ₄ ; 0.03%, and it was confirmed that the reaction proceeded almost quantitatively (99.3%). Impurities were Ca <5 ppm, Cu <5 ppm, Fe <5 ppm, Mg <5 ppm, Mn <1 ppm, Si <10 ppm.
[0043]
[Example 4]
176 g of (NH ₄ ) ₃ AlF ₆ produced as the same industrial waste as used in Example 1 was measured and dispersed in 5.0 kg of water. Then, after adding 119g of NaF, it stirred at 90 degreeC for 6 hours. The pH of the solution was 7.5. Thereafter, the solution was cooled to 40 ° C. and then separated into a precipitate and a reaction filtrate by suction filtration.
[0044]
The collected precipitate was dispersed in 1 kg of water at 40 ° C., washed with the precipitate, then separated into a precipitate and a washing filtrate by filtration, and the precipitate was dried at 105 ° C. for 6 hours.
[0045]
Furthermore, the reaction filtrate was concentrated at 130 ° C. for 3 hours. The concentrate was cooled to 25 ° C. to precipitate crystals. The crystals and the filtrate were separated by filtration, and the crystals were dried at 105 ° C. for 6 hours.
The weight of the obtained precipitate was 186 g. Moreover, the crystal weight obtained from the liquid which concentrated the filtrate was 98g.
The average particle size of the obtained precipitate was 1.6 μm.
[0046]
As a result of further XRD analysis of the precipitate and the crystal, the precipitate was assigned to Na ₃ AlF ₆ and the crystal was assigned to NH ₄ F. The ammonia content in Na ₃ AlF ₆ was 0.02%, and other impurities were Ca <5 ppm, Cu <5 ppm, Fe <5 ppm, Mg <5 ppm, Mn <1 ppm, Si <10 ppm. Furthermore, Na in NH ₄ F; 0.06%, and it was confirmed that the reaction had progressed quantitatively (98.4%). Impurities were Ca <5 ppm, Cu <5 ppm, Fe <5 ppm, Mg <5 ppm, Mn <1 ppm, Si <10 ppm.
[0047]
[Example 5]
135 g of (NH ₄ ) ₃ AlF ₆ produced as the same industrial waste as that used in Example 1 was measured and dispersed in 3.5 kg of water. Thereafter, 116 g of Na ₂ CO ₃ was added, followed by stirring at 40 ° C. for 6 hours. The pH of the solution was 7.3. Thereafter, the precipitate and the reaction filtrate were separated by suction filtration.
[0048]
The collected precipitate was dispersed in 1 kg of water at 40 ° C., washed with the precipitate, then separated into a precipitate and a washing filtrate by filtration, and the precipitate was dried at 105 ° C. for 6 hours.
[0049]
Furthermore, the reaction filtrate was concentrated at 130 ° C. for 4 hours. The concentrate was cooled to 25 ° C. to precipitate crystals. The crystals and the filtrate were separated by filtration, and the crystals were dried at 105 ° C. for 6 hours.
The weight of the obtained precipitate was 145 g. Moreover, the crystal weight obtained from the liquid which concentrated the filtrate was 97g.
The average particle size of the obtained precipitate was 1.8 μm.
[0050]
As a result of XRD analysis of the precipitate and the crystal, the precipitate was assigned to Na ₃ AlF ₆ and the crystal was assigned to (NH ₄ ) ₂ CO ₃ . Moreover, the ammonia content in Na ₃ AlF ₆ was 0.04%, and other impurities were Ca <5 ppm, Cu <5 ppm, Fe <5 ppm, Mg <5 ppm, Mn <1 ppm, Si <10 ppm. Furthermore, Na in (NH ₄ ) ₂ CO ₃ ; 0.05%, and it was confirmed that the reaction had progressed quantitatively (99.3%). Impurities were Ca <5 ppm, Cu <5 ppm, Fe <5 ppm, Mg <5 ppm, Mn <1 ppm, Si <10 ppm.
[0051]
[Example 6]
81 g of (NH ₄ ) ₃ AlF ₆ produced as the same industrial waste as that used in Example 1 was measured and dispersed in 3.5 kg of water. Thereafter, 112 g of NaNO ₃ was added, followed by stirring at 90 ° C. for 6 hours. The pH of the solution was 7.3. Thereafter, the solution was cooled to 40 ° C. and then separated into a precipitate and a reaction filtrate by suction filtration.
[0052]
The collected precipitate was dispersed in 1 kg of water at 40 ° C., washed with the precipitate, then separated into a precipitate and a washing filtrate by filtration, and the precipitate was dried at 105 ° C. for 6 hours.
[0053]
Furthermore, the reaction filtrate was concentrated at 130 ° C. for 4 hours. The concentrate was cooled to 25 ° C. to precipitate crystals. The crystals and the filtrate were separated by filtration, and the crystals were dried at 105 ° C. for 6 hours.
The weight of the obtained precipitate was 87 g. Moreover, the crystal weight obtained from the liquid which concentrated the filtrate was 98g.
The average particle size of the obtained precipitate was 1.8 μm.
[0054]
As a result of further XRD analysis of the precipitate and the crystal, the precipitate was assigned to Na ₃ AlF ₆ and the crystal was assigned to NH ₄ NO ₃ . The ammonia content in Na ₃ AlF ₆ was 0.05%, and other impurities were Ca <5 ppm, Cu <5 ppm, Fe <5 ppm, Mg <5 ppm, Mn <1 ppm, Si <10 ppm. Furthermore, Na in NH ₄ F; 0.05%, and it was confirmed that the reaction had progressed quantitatively (98.9%). Impurities were Ca <5 ppm, Cu <5 ppm, Fe <5 ppm, Mg <5 ppm, Mn <1 ppm, Si <10 ppm.
[0055]
【The invention's effect】
The present invention can convert an ammonium complex of metal fluoride, which has been treated as industrial waste with little reuse in the past, to a reusable metal fluoride inorganic complex by simple means, The industrial effect is extremely large.

Claims (6)

Metal fluoride ammonium complex generated as industrial waste and inorganic salt (RX : R represents a cation, X represents an anion ) are reacted in solution to recover the metal fluoride inorganic complex and ammonium salt. A method for recovering a metal fluoride characterized by the above.
However, the ammonium complex of the metal fluoride is at least one of ammonium fluoride (NH ₄ ) _y MF _z containing at least one metal M of Al, Fe and Si (provided that y = 1, 2 or 3) Any one and z = 4, 5, 6 or 7).
The cation (R) of the inorganic salt is at least one of Na and K. 2. The method according to claim 1, wherein the anion (X) of the inorganic salt is at least one of Cl, SO ₄ , F, CO ₃ , HCO ₃ , NO ₃ , and PO ₄ . The method according to claim 1 or 2, wherein the metal fluoride ammonium complex is formed during the surface treatment of aluminum or an alloy thereof. The method according to any one of claims 1 to 3, wherein the ammonium complex of metal fluoride contains Mg as an impurity. The method according to any one of claims 1 to 4, wherein the pH during the reaction is 5 to 9. A method for reusing a metal fluoride ammonium complex, wherein the metal fluoride inorganic complex and / or ammonium salt obtained by the method according to any one of claims 1 to 5 is reused.