JP2002346596A - Method for treating oil-containing sludge containing tantalum/niobium, and tantalum/niobium recovering method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tantalum and/or niobium-containing raw material suitable for the efficient production of various products by removing an oil component from oil-containing sludge containing tantalum and/or niobium, which is low in the content of tantalum and/or niobium and contains a large amount of the oil component and is said to be difficult in the recovery of tantalum and/or niobium heretofore, by drying evaporation, the suspension or dissolution into water or an organic solvent, or saponification of the oil component. SOLUTION: The method for treating the oil-containing sludge containing tantalum and/or niobium includes a process for taking out an oil-containing solid from the oil-containing sludge containing tantalum and/or niobium, a process for drying the taken-out oil-containing solid to obtain the dried solid, a process for slurrying the dried solid with water or the organic solvent to heat and stirr the formed slurry and a process for obtaining the tantalum and/or niobium-containing raw material from which the oil component is removed by subjecting the slurry after heating and stirring to solid-liquid separation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for treating oil-containing sludge containing tantalum / niobium and a method for recovering tantalum / niobium.

[0002]

2. Description of the Related Art Tantalum is widely used for its corrosion resistance,
Because of its excellent heat resistance, it is used in various chemical devices such as distillation towers, autoclaves, heat exchangers, and spinning nozzles for chemical fibers for the chemical industry. In general, a tantalum oxide film has a characteristic called a valve action (a characteristic in which the electrode operates as a dielectric when the electrode is a positive electrode, but does not operate as a dielectric when the electrode is a negative electrode, that is, a rectifying characteristic). Therefore, it is used as an electrode material for electrolytic capacitors, and is used in transport equipment, electronic equipment, electronic control equipment, and the like. In addition, surface acoustic waves (SA
W) A single crystal lithium tantalate wafer is used as a filter, and the demand for the filter has been greatly increased with the expansion of the mobile communication market. Further, tantalum carbide is used as a material for a carbide cutting tool, and tantalum oxide is used as an additive for an optical lens. Tantalum is very important and its demand is increasing.

On the other hand, niobium stabilizes carbon in steel,
Since it has the effect of preventing intergranular corrosion, it is used as a steel additive, and this is its largest use. In addition, as a conductive tube attached to the lamp light emitting part of the high-pressure sodium lamp,
Niobium alloys have been put into practical use, and are further used as superconducting materials and additive elements for superalloys.Niobium oxide is also used as optical glass or electronic ceramics, as a raw material for lithium niobate, and as a raw material for carbides. ing.

[0004] There are several methods for producing tantalum oxide and / or niobium oxide, and the hydrofluoric acid dissolution-solvent extraction method described below is common. FIG. 2 shows a general manufacturing process of tantalum oxide and niobium oxide. As shown in FIG. 2, first, ore such as tantalite and raw materials such as scrap of a tantalum capacitor are crushed and dissolved with hydrofluoric acid, and then the concentration of the solution is adjusted by adding sulfuric acid. Next, this adjusted liquid is filtered with a filter press, made into a clean solution, and subjected to solvent extraction with MIBK (methyl isobutyl ketone), whereby tantalum and niobium are extracted into MIBK. At this time, the impurities iron, manganese, silicon, etc. contained in the raw material remain in the raffinate,
The impurities are removed.

[0005] When the MIBK containing tantalum and niobium thus obtained is back-extracted with dilute sulfuric acid, niobium is transferred to an aqueous solution, and pure tantalum remains in MIBK. The tantalum in MIBK is purified, back-extracted with water, and transferred to an aqueous solution.
Collect and reuse BK. On the other hand, niobium in the aqueous solution is M
Extract again with IBK, extract a small amount of tantalum, and purify niobium in the aqueous solution to a pure one. MIBK at the time of this niobium purification is combined with the solvent before separation of tantalum and niobium. When aqueous ammonia is added to each of the tantalum and niobium solutions thus purified, tantalum hydroxide and niobium hydroxide precipitate. Further, the precipitate of the hydroxide is filtered, dried, and finally calcined to obtain tantalum oxide and niobium oxide.

[0006] In spite of the fact that such tantalum / niobium is a rare product, the demand has been increasing significantly in recent years, and the supply of tantalum / niobium raw materials cannot keep up with demand. This situation is particularly pronounced in tantalum. For this reason, it has been attempted to reuse waste materials and unnecessary products generated in the production process of tantalum and niobium as raw materials.

[0007] As tantalum or niobium-containing waste,
There are oily sludges generated during the processing of lithium tantalate or lithium niobate. The oil-containing sludge is composed of cutting particles of SiC, lithium tantalate or lithium niobate and cutting oil, which are abrasive grains, and about 70 to 95% of the components excluding the cutting oil is SiC.

[0008]

However, when this oil-containing sludge is directly dissolved in HF, the oil dissolved or mixed in the solution is dissolved in the solvent (such as MIBK) at the time of extracting the solvent, which adversely affects the separation and purification. The simplest method of removing oil from oil-containing sludge is to remove oil by roasting, but there is a problem in that roasting costs are high because the tantalum / niobium pure content is low. Also, a method of recovering tantalum / niobium by slurping oil-containing sludge directly with water and dispersing lithium tantalate / lithium niobate having a low specific gravity in water is conceivable, but the recovery efficiency is poor and not practical. Is also difficult to handle due to poor dispersion.

The present invention has been made in view of the above circumstances, and has a low content of tantalum and / or niobium and contains a large amount of oil, and it has been conventionally difficult to recover tantalum and / or niobium. And / or niobium-containing oil-containing sludge, by removing the oil content by dry evaporation and suspension or dissolution in water or an organic solvent, or saponification, to obtain tantalum and / or niobium suitable for efficient production of various products. The purpose is to obtain the contained raw materials.

[0010]

In order to achieve the above object, a method for treating an oil-containing sludge containing tantalum / niobium according to claim 1 is a method for treating oil-containing solids from tantalum and / or niobium-containing oil-containing sludge. Taking out, drying the taken out oil-containing solid to obtain a dry solid, slurrying the dried solid with water or an organic solvent, heating and stirring, and heating and stirring the slurry after heating. Obtaining a tantalum and / or niobium-containing raw material from which oil has been removed by solid-liquid separation.

According to a second aspect of the present invention, in the method for treating an oil-containing sludge containing tantalum / niobium, a sodium compound or a potassium compound is used in the drying step or the step of slurrying and heating and stirring. It is characterized by doing.

According to a third aspect of the present invention, there is provided the method for treating an oil-containing sludge containing tantalum / niobium according to the second aspect of the present invention, wherein the extracted oil-containing solid is mixed with a sodium compound or a potassium compound and then dried. It is characterized by making it.

According to a fourth aspect of the present invention, there is provided the method for treating an oil-containing sludge containing tantalum / niobium, wherein the sodium compound or the potassium compound is a carbonate or a bicarbonate in the invention of the third aspect. Features.

[0014] The method for treating an oil-containing sludge containing tantalum / niobium according to claim 5 is described in claims 1 to 4.
In the invention according to any one of the above, the drying is 150 to
It is performed at 300 ° C.

[0015] The method for treating an oil-containing sludge containing tantalum / niobium according to claim 6 is described in claims 1 to 5.
In the invention described in any one of the above, the heating and stirring may be performed for 35 hours.
It is characterized in that it is performed at ~ 95 ° C.

The method for treating an oil-containing sludge containing tantalum / niobium according to claim 7 is described in claims 1 to 6.
The invention according to any one of the above, wherein a surfactant is used during the slurrying or the heating and stirring.

[0018] According to an eighth aspect of the present invention, there is provided a method for recovering tantalum / niobium according to any one of the first to seventh aspects of the present invention, further comprising the tantalum and / or niobium from which the oil has been removed. The method is characterized by comprising a step of dissolving the raw material with hydrofluoric acid or a mixed acid of hydrofluoric acid and another mineral acid to recover tantalum and / or niobium in the hydrofluoric acid solution or the mixed acid solution.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. [Method of Treating Tantalum and / or Niobium-Containing Sludge] First, the method of treating oil-containing sludge containing tantalum and / or niobium of the present invention will be described with reference to FIG. The oil-impregnated sludge containing tantalum and / or niobium used in the present invention is an oil-impregnated sludge generated during the processing of lithium tantalate or lithium niobate, and the oil-impregnated sludge is composed of SiC, which is an abrasive grain.
And cutting oil and cutting oil of lithium tantalate or lithium niobate, and 70-
About 95% is SiC. The oil-containing sludge is in a state of a solid (oil-containing solid) containing oil on the upper side and oil on the lower side.

First, an oil-containing solid is taken out from an oil-containing sludge containing tantalum and / or niobium. The method for removing the oil-containing solid matter is not particularly limited, but it is common to extract the upper oil by tilting the container or using a pump, and then remove the oil-containing solid matter remaining in the container. is there. The removed oil-containing solid matter may be used as it is in the next drying step (or mixing step). For example, the oil-containing solid matter is taken out on a table having a strong net-like upper surface and an oil tray. It is preferable that the oil-containing solid is left to stand and the oil is sufficiently cut off before being used in the next drying step (or mixing step).
Since the grinding waste is fine particles, about 5 to 10% of the oil content still remains in the extracted oil-containing solid matter.

Next, in order to remove the oil contained in the taken-out oil-containing solid, the taken-out oil-containing solid is dried at 150 to 300 ° C. to obtain a dry solid. The reason for setting this temperature range is that when dried at a temperature lower than 150 ° C., the evaporation of the oil is small and the oil in the obtained tantalum and / or niobium-containing raw material is large,
This is because drying at a temperature exceeding 00 ° C. may cause ignition of oil and increase the drying cost.
The gaseous oil generated at this time is treated separately.

Next, after the dried solid is crushed, it is slurried with water or an organic solvent. The use of water for slurrying the dried solid is advantageous in terms of cost, but it is preferable to use an organic solvent having a high oil-solubility in terms of oil removal. As the organic solvent, acetone or alcohols are preferable because they have a high dissolving power for oil components, are low in cost, and are easily removed by evaporation or washing with water. Here, the alcohols are defined as alcohols in the Class 4 dangerous goods of the Fire Services Act, and include methanol, ethanol (including denatured alcohols), 1-propanol, and 2-propanol (isopropyl alcohol). . Chlorine-based organic solvents such as trichloroethylene and tetrachloroethylene are excellent in terms of dissolving power of oil, but are not preferable because they have a bad influence on the environment. When an organic solvent is used, it is desirable to remove the organic solvent by heating the obtained raw material, or in the case of a water-soluble organic solvent, by washing with water. In addition, both water and an organic solvent may be used simultaneously.

Next, the slurry is heated at 35-95 ° C. for 0.5-0.5.
Heat and stir for 20 hours. Since this slurry contains lithium, it exhibits strong alkalinity, and even when water is used for slurrying, part of the oil in the solid is saponified by heating and stirring to become water-soluble, and part of the oil is Suspend in Furthermore, when an organic solvent is used for slurrying, a part of the oil component is directly dissolved in the organic solvent. The oil component is separated from the solid by the above-described mechanism. The reason why the temperature is set within the above range is that if the temperature is lower than 35 ° C., the saponification reaction tends to be insufficient, and the oil content is not sufficiently reduced.
If the temperature exceeds ℃, the heating cost increases. In addition,
It is more preferable that the slurry is heated and stirred at 50 to 80 ° C. because the balance between removal of oil and heating cost can be achieved. Also,
If the heating worship time is less than 0.5 hours, saponification and suspension do not proceed sufficiently, and oil removal becomes insufficient. Even if heating and stirring for more than 20 hours, saponification and suspension no longer proceed. It is a waste of time and money.

Next, the slurry after heating and stirring is subjected to solid-liquid separation. As this solid-liquid separation method, for example, the slurry after heating and stirring is filtered as it is. Alternatively, as another solid-liquid separation method, after heating and stirring, the slurry is allowed to stand to settle solids, and then the liquid phase is extracted. However,
When the solid is settled by allowing the slurry to stand, SiC easily settles, but tantalum and / or niobium-containing substances take a long time to settle. It should be noted that insufficient settling time results in loss of tantalum and / or niobium. The pH may be adjusted to about 2 with an acid such as sulfuric acid to improve the sedimentation. However, the oil dissolved in the liquid phase may precipitate on the surface of the liquid phase in some cases, but the precipitated oil must be extracted together with the liquid phase.

Solid-liquid separation can be carried out by these two methods. However, when a sodium compound or a potassium compound described later is not mixed, oil removal may be insufficient. It is preferable that the oil content is sufficiently reduced by the above method. That is, after performing heating and stirring, the slurry is allowed to stand to precipitate solids, then the liquid phase is extracted, and then water is added and stirred,
After reslurrying, the solid content is collected again. Alternatively, after the slurry is filtered, the filtered solid is reslurried and solid-liquid separation is performed again. Alternatively, not only reslurrying but also heating and stirring are performed. Alternatively, after filtration,
Wash with water.

In such a method for treating an oil-containing sludge containing tantalum and / or niobium, as shown in FIG. 1, a sodium compound or a potassium compound can be used to accelerate the saponification reaction. It may be used in any of a drying step, a slurrying step, and a heating and stirring step.However, a sodium compound or a potassium compound is mixed with a solid substance taken out from an oil-containing sludge, and then dried. It is most preferable because saponification sometimes progresses. As the sodium compound or the potassium compound, for example, chloride, sulfate, hydroxide, carbonate, bicarbonate and the like can be used.
In the case of mixing before drying, if a carbonate or bicarbonate is used, the properties of the powder after the mixing become a smooth mixed powder and the viscosity is small, which is suitable for handling. Although there is no significant difference in the oil removing effect between the sodium compound and the potassium compound, the sodium salt is usually advantageous from the viewpoint of cost. The amount of the sodium compound or potassium compound to be used is 1 to 100% by weight based on the weight of the solids taken out.
Is preferred. The amount used is 1 wt% of the weight of the solids taken out
%, There is almost no saponification promoting effect, and 100%
When used in excess of this, the effect of promoting saponification hardly increases. From the balance between saponification promoting effect and cost, 5-50
wt% is more preferred, and 10-30 wt% is even more preferred. When a sodium compound or a potassium compound is used, the oil component is sufficiently removed, but after dissolution of hydrofluoric acid, a compound containing tantalum and / or niobium may be precipitated by sodium or potassium as described later (particularly, This is remarkable when a potassium compound is used. Therefore, it is desirable that sodium or potassium is sufficiently reduced by washing with water or an aqueous solution of a mineral acid other than hydrofluoric acid before dissolving with hydrofluoric acid.

Further, a surfactant may be used during the slurrying or the heating and stirring. By using a surfactant, the oil component is easily dissolved in water or an organic solvent. As surfactants, anionic,
Any of cationic, amphoteric and nonionic can be used. Further, a detergent containing a surfactant such as a kitchen detergent may be used. The surfactant may be pre-mixed with water or an organic solvent used for slurrying and then slurried, or added at the time of slurrying, at the time of heating and stirring or at the end of heating and stirring. Is also good. The amount of the surfactant used depends on the amount of water or organic solvent used for slurrying.
0.1 to 50 g per 1 is preferable. If the amount is less than 0.1 g, the effect of easily dissolving the oil component in water or an organic solvent cannot be obtained, and even if the amount exceeds 50 g, the effect does not increase.

The solid thus obtained is the tantalum and / or niobium-containing raw material from which the oil component has been removed, which is the object of the present invention. The oil content in the raw material from which the oil content has been removed is calculated as a hexane extractable substance per 1 kg of the total amount of the raw material in terms of tantalum oxide and niobium oxide as 1000.
mg or less, preferably 300 m
g or less, more preferably 100 mg or less, and even more preferably 20 mg or less, substantially not containing any oil. If the hexane extractables exceeds 1000 ppm of the total amount of the tantalum oxide equivalent and the niobium oxide equivalent in the raw material from which the oil has been removed, after dissolving with hydrofluoric acid or the like, use an organic solvent such as MIBK. When separation and purification are performed by solvent extraction, the oil component dissolves in the organic solvent, resulting in adverse effects such as a reduction in the separation / purification ability or a deterioration in the phase separation between the organic phase and the aqueous phase. When the organic solvent is circulated in the separation / purification by solvent extraction, the oil content in the raw material from which the oil content has been removed is 300 pp with respect to the total amount of the tantalum oxide equivalent and the niobium oxide equivalent.
m or less, there is no adverse effect of oil for a long time,
Even if it occurs, it is slight, and if it is 100 ppm or less, no adverse effect due to oil will occur for a longer period of time. If it occurs, it will be very slight. If it is 20 ppm or less, the adverse effect due to oil will not occur semipermanently. .

[Method of recovering tantalum and / or niobium] The tantalum and / or niobium-containing raw material from which the oil has been gradually removed is dissolved in hydrofluoric acid or a mixed acid of hydrofluoric acid and another mineral acid to obtain tantalum and / or niobium. And / or niobium can be recovered in a hydrofluoric acid solution or a mixed acid solution at a high recovery rate. Examples of other mineral acids include sulfuric acid, hydrochloric acid, nitric acid, and perchloric acid, and sulfuric acid is most preferable because it is inexpensive and does not adversely affect the subsequent solvent extraction step. For example, the use of hydrochloric acid may have adverse effects such as difficulty in separating niobium and iron.

For dissolution, the tantalum and / or niobium-containing raw material from which the oil has been removed may be slurried with water and then hydrofluoric acid or hydrofluoric acid and other mineral acids may be added, or hydrofluoric acid or hydrofluoric acid may be added. A mixed acid of an acid and another mineral acid may be placed in a dissolving tank and then a raw material from which oil has been removed may be added. Hydrofluoric acid can be used as long as it has a concentration of 10 wt% or more from the viewpoint of dissolving power. However, it is usually sold for industrial use or for electronic industry.
It is preferable to use hydrofluoric acid such as wt% as it is. From the viewpoint that it is preferable to increase the concentrations of tantalum and niobium in the solution and reduce the amount of drainage, from the viewpoint that hydrofluoric acid of about 50 wt% or more, or a mixed acid of hydrofluoric acid of about 50 wt% or more and other acids is placed in the dissolution tank. After that, it is preferable to add the raw material from which the oil has been removed.

The amount of hydrofluoric acid used is preferably such that the amount of hydrofluoric acid present in the liquid after dissolution is 0.1 to 10 mol / L. If the concentration of free hydrofluoric acid in the solution is less than 0.1 mol / L, the recovery of tantalum / niobium is insufficient due to insufficient dissolution, and if it exceeds 10 mol / L, tantalum and niobium are used in the subsequent solvent extraction. The difference in the extraction behavior is small, adversely affecting separation and purification. When deciding the amount of hydrofluoric acid to be used, Ta,
Calculate for impurities contained in non-negligible amounts such as Nb, Li and Fe, calculate the amount theoretically necessary for dissolution,
The required amount of free hydrofluoric acid after dissolution may be added to the theoretical amount.
Since SiC is hardly dissolved by hydrofluoric acid, it can be ignored. The amount of hydrofluoric acid used does not change even when other mineral acids are used in combination. When using other mineral acids in addition to hydrofluoric acid for dissolution, the amount of other mineral acids used is the total amount of hydrofluoric acid and other mineral acids that are free in the liquid after dissolution, and It is preferable that the amount is 25 mol / L or less. If it exceeds 25 mol / L in the dissolution solution, even if the amount of free hydrofluoric acid is 10 mol / L or less, it will adversely affect the separation and purification in the subsequent solvent extraction as described above.

The dissolution is controlled by controlling the dissolution
It is preferably carried out at a temperature of 100 ° C. If the temperature is lower than 30 ° C., the dissolution tends to be insufficient. If the temperature is higher than 100 ° C., the reaction is so intense that there is a risk of overflowing from the melting tank. The dissolution ripening can be controlled by changing the rate of addition of the acid or the raw material according to the temperature. Further, a cooling / heating device may be used. At the end of the addition to the dissolution tank, the dissolution of tantalum and / or niobium is often still insufficient, so stirring is further continued for 3 to 72 hours.
It is preferable to increase the recovery of tantalum and / or niobium. After the dissolution or, if necessary, addition of hydrofluoric acid, mineral acid, water or the like to adjust the solution, the solid-liquid separation is usually carried out by filtration or the like. Liquid adjustment may be performed after solid-liquid separation.

In the case where a sodium compound or a potassium compound is used for treating an oil-containing sludge containing tantalum and / or niobium, for example, a tantalum and / or niobium-containing hydrofluoric acid solution or a hydrofluoric acid and another mineral acid after solid-liquid separation are used. When the mixed acid solution is cooled, a tantalum / niobium compound is often precipitated. As described above, it is desirable to reduce sodium or potassium by washing with water or acid before dissolving hydrofluoric acid to prevent the tantalum / niobium compound from being precipitated.
Collected by filtration, etc., alkali dissolution, water washing, and acid washing are performed to reduce sodium or potassium sufficiently, and then treated again by dissolving with hydrofluoric acid or a mixed acid of hydrofluoric acid and other mineral acids. It is possible.

The tantalum thus obtained and / or
Or niobium-containing hydrofluoric acid solution or mixed acid solution (raw material solution)
The concentration of tantalum and / or niobium therein is not particularly limited. The higher the concentration is, the more advantageous it is because the amount of wastewater is reduced, but in general, the total amount of tantalum and niobium is 30 to
It is 300 g / L. Usually, tantalum and niobium in the raw material liquid are H ₂ Ta (Nb) F ₇ or H ₂ NbOF ₅
It is said to exist in a form like Other than this, the surplus hydrofluoric acid that exists free is 0.1 to 10 m
ol / L exists. In addition, the total amount of surplus hydrofluoric acid and other mineral acids that exist free is converted to monobasic acid,
There is 1 to 25 mol / L. When the acid concentration is within this range, the above-mentioned adverse effects do not occur in the solvent extraction. In addition, it often contains impurities such as iron derived from oil-containing sludge as a raw material or used chemicals. The necessary range and preferred range of the oil content in the tantalum / niobium-containing hydrofluoric acid solution or the mixed acid solution (raw material solution) and the reason therefor are the same as those in the raw material from which the oil content before dissolution was removed.

Using a hydrofluoric acid solution or a mixed acid solution in which tantalum and / or niobium obtained by such a recovery method are recovered in high yield, tantalum oxide, niobium oxide, tantalum carbide, niobium carbide, fluorine, etc. Various tantalum / niobium products can be manufactured, including potassium tantalate fluoride, potassium fluoroniobate, tantalum, niobium, tantalum nitride and niobium nitride.

The tantalum oxide and / or niobium oxide, the tantalum carbide and / or the carbon dioxide are prepared using a hydrofluoric acid solution or a mixed acid solution from which tantalum and / or niobium obtained by the above-mentioned recovery method are recovered in high yield. Methods for producing niobium, potassium fluorotantalate and / or potassium fluoroniobate, tantalum and / or niobium and tantalum nitride and / or niobium nitride are described, but methods for producing these tantalum / niobium products are known. And the method is not particularly limited.

[Production method of tantalum oxide / niobium oxide]
In order to produce tantalum oxide and / or niobium oxide, first, tantalum and / or niobium in a hydrofluoric acid solution or a mixed acid solution obtained by the above-mentioned recovery method are extracted with a solvent. The method of extracting with a solvent can be performed by a known method, and is not particularly limited. For example, it can be preferably performed using a solvent such as MIBK, diluted sulfuric acid, or water according to the procedure shown in FIG. Thereby, further removal of impurities and separation and purification of Ta / Nb can be performed.

Next, ammonia is added to the obtained extraction solvent to precipitate tantalum hydroxide and / or niobium hydroxide. This ammonia can be added in gaseous form, but is preferably added in the form of an aqueous ammonia solution (NH ₄ OH). Further, ammonium bicarbonate or ammonium carbonate can be added in an aqueous solution. The concentration of the aqueous ammonia solution and the amount thereof may be appropriately determined according to the amounts of tantalum and / or niobium in the extraction solvent, and are not particularly limited. Further, the precipitate-containing solution thus obtained is filtered to separate a precipitate composed of tantalum hydroxide and / or niobium hydroxide. After the obtained precipitate is dried and calcined, tantalum oxide and / or niobium oxide are obtained.

[Method for producing tantalum carbide / niobium carbide]
Tantalum carbide and / or niobium carbide can be obtained by obtaining tantalum oxide and / or niobium oxide by the above-described method, and then reducing and roasting the obtained oxide with carbon. For example, it can be manufactured by mixing tantalum oxide and carbon black with a ball mill or the like, shaping this into a small briquette, and heating it at 1600 to 1800 ° C.

[Method for Producing Potassium Fluorotantalate / Potassium Niobate] In order to produce potassium fluoride tantalate and / or potassium fluoroniobate, first, the hydrofluoric acid obtained by the above-mentioned recovery method is used. Extract tantalum and / or niobium in solution or mixed acid solution with solvent. The method of extracting with a solvent can be performed by a known method, and is not particularly limited. For example, it can be preferably performed using a solvent such as MIBK, diluted sulfuric acid, or water according to the procedure shown in FIG. Thereby, further removal of impurities and separation and purification of Ta / Nb can be performed.

Next, a potassium salt is added to the obtained extraction solvent to precipitate potassium fluoride tantalate and / or potassium fluoride niobate crystals, and this precipitate is separated by filtration and dried. The potassium fluoride tantalate and / or potassium fluoride niobate crystals obtained by filtration may be recrystallized to increase the purity. Preferred potassium salts include potassium fluoride, potassium chloride, potassium hydroxide and the like.

[Method of producing tantalum / niobium] Tantalum and / or niobium are obtained by reducing potassium fluoride tantalate and / or potassium niobate obtained by the above-described method to obtain tantalum and / or niobium. . The reduction at this time is generally performed by sodium reduction. The sodium reduction is performed, for example, as follows. First, the reaction vessel is heated while being filled with an inert gas (for example, Ar gas),
At the time when the temperature is raised to about ° C, a predetermined amount of metallic Na is introduced. Then, the temperature is further increased by heating to evaporate the metal Na to reach the surface of the potassium fluorotantalate, and the reduction reaction proceeds from the surface.

[Production method of tantalum nitride / niobium nitride]
Tantalum nitride and / or niobium nitride are obtained by nitriding the tantalum and / or niobium obtained by the above-described method to obtain tantalum nitride and / or niobium nitride. The nitriding treatment is performed, for example, by powdering or pelleting tantalum and / or niobium under a nitrogen atmosphere under a nitrogen atmosphere.
It can be performed by heating at 0 to 1100 ° C, but is not limited to this.

[0043]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. (Example 1) Oil-containing sludge generated during the processing of lithium tantalate was prepared as a raw material. Open the lid of the can containing the oil-impregnated sludge, extract most of the oil with a pump, take out the oil-impregnated solid using an iron bar, and remove the oil pan with the top formed into a strong mesh. On a table with
Leave it for one day to remove oil. A part of the oil-containing solid matter which was taken out and sufficiently cut off oil was collected, and after dissolving hydrofluoric acid, the hexane extract specified in "JIS K 0102-1998 Factory drainage test method" was measured as an oil content. The oil content in the oil-containing solid matter that had been sufficiently cut off was 7%.

20.0 kg of the oil-containing solid material that had been taken out and sufficiently oiled was placed in a dryer and dried at 200 ° C. for 8 hours. The weight of the resulting dried solid was 18.8 kg. Next, the dried solid was crushed by a sample mill to obtain a dried and crushed solid. A component analysis was performed on the dried and crushed solid. Oil (hexane extract)
0.95% (6.25% based on the total amount of Ta ₂ O ₅ + Nb ₂ O ₅ ). The components other than the oil component are T
a, Nb, Li, and Fe were measured by hydrofluoric acid dissolution-ICP emission spectroscopy and converted to oxides. Regarding SiC, Si was measured by a fluorescent X-ray method and converted into SiC.
Table 1 shows the results of the component analysis of the dried and crushed solids.

[0045]

[Table 1]

6.0 kg of the dried and crushed solids is
After slurrying with L and raising the temperature to 80 ° C., the mixture was heated and stirred at 80 ° C. for 5 hours. After the slurry after heating and stirring was filtered by vacuum filtration, the filtered solid was reslurried with 12 L of water, and stirred for 1 hour without heating.
Vacuum filtration was performed to recover 6.6 kg of a solid from which the oil was removed. For dissolution, 600 mL of 55% hydrofluoric acid was put into a beaker made of PTFE (polytetrafluoroethylene), and 3.0 kg of a tantalum and / or niobium-containing raw material from which oil was removed was added over 3 hours while stirring with a stirrer. Then, the mixture was stirred for 6 hours after completion of the addition.
After the dissolution was completed, the solution was filtered, and the filtrate was added with 18 mol /
150 mL of L (36 mol / L in terms of monobasic acid) sulfuric acid was added, and water was further added to adjust the total liquid volume to 1500 mL. The oil content of this dissolved / liquid preparation was measured to be 72 mg
/ L, and the oil content in the tantalum and / or niobium-containing raw material from which the oil content has been removed is 260 ppm with respect to Ta ₂ O ₅ + Nb ₂ O ₅ . Further, Ta and Nb were hardly contained in the filtration residue of the solution.

(Example 2) 40 kg of an oil-containing solid (oil content: 7 wt%) taken out in Example 1 and sufficiently cut off oil and 10 kg of sodium carbonate were mixed using a mixer. What had been a mass became a powdery solid after mixing, and 50 kg was obtained. 20 kg of the powdery solid material mixed with the sodium carbonate was put into a drier and dried at 200 ° C. for 8 hours. The weight of the obtained dry solid was 18.1 kg. Subsequent operations were performed under the same conditions as in Example 1. However, the used amount of the tantalum and / or niobium-containing raw material from which the dry solid used for slurrying and the oil used for dissolving were removed was determined by the amount of tantalum and / or niobium contained in the solid in Example 1. Adjusted to be the same as in the case (7.2 kg of dry solid used for slurrying, yield of oil-removed solid 6.
6 kg, dissolving oil removal solid content 3.0 kg).

Comparative Example 1 The procedure of Example 1 was repeated except that the heating and stirring were carried out at room temperature (about 18 ° C.) without heating using 6.0 kg of the dried and crushed solid of Example 1. Did the same thing. The amount of the solid used for slurrying and dissolving was adjusted so that the amount of tantalum and / or niobium contained in the solid was the same as in Example 1.

(Comparative Example 2) Dry solid substance of Example 2 7.2
kg at room temperature without heating and stirring.
° C), except that the treatment was the same as in Example 2. The amount of the solid used for slurrying and dissolving was adjusted so that the amount of tantalum and / or niobium contained in the solid was the same as in Example 2.

Comparative Example 3 8.0 kg of the solid obtained by mixing sodium carbonate of Example 2 was treated in the same manner as in Example 2 except that it was not dried. The amount of the solid used for slurrying and dissolving was adjusted so that the amount of tantalum and / or niobium contained in the solid was the same as in Example 2.

(Comparative Example 4) 20 kg of a solid (oil content: 7 wt%) taken out in Example 1 and sufficiently oiled was added to 40 L of water.
After slurrying in, although most of SiC had settled, tantalum and / or niobium were settled for a short time until dispersed in water, and the dispersed phase was shaken out.
To the remaining solid mainly composed of SiC, 40 L of water was again added to form a slurry, and the slurry was settled for a short time, then the dispersed phase was extracted, and combined with the previously extracted dispersed phase. Thus, SiC
And separation. PH of the combined dispersed phase with sulfuric acid
Was adjusted to about 2 and tantalum and / or
Alternatively, the niobium-containing substance was allowed to settle, and the supernatant was extracted. After extracting the supernatant, 60 L of water was added to form a slurry, and the pH was adjusted to about 2 with sulfuric acid to precipitate the tantalum and / or niobium-containing substance, and the supernatant was extracted. This process is performed up to 4 times of supernatant extraction,
A tantalum and / or niobium containing material was obtained. Thus, the oil content was reduced. The tantalum and / or niobium-containing substance thus obtained was dissolved, prepared, and filtered in the same manner as in Examples and Comparative Examples. In Table 2,
The results of oil measurement of each of the above Examples and Comparative Examples are shown.

[0052]

[Table 2]

The tantalum and / or niobium-containing raw materials from each of the Examples and Comparative Examples from which the oil was removed were dissolved in hydrofluoric acid to recover tantalum and / or niobium in the hydrofluoric acid solution. However, Comparative Example 4
The recovery rate of tantalum was about 70% and the recovery rate of niobium was about 80%. In the other Examples and Comparative Examples, the recovery rates of both tantalum and niobium were 98% or more.

(Repeated extraction test by MIBK)
Under the same conditions as in Comparative Example 1 and Comparative Example 1, the scale was increased to prepare dissolution / liquid preparation solutions. As shown in Table 3, the oil content in these two kinds of dissolving / liquid adjusting liquids was almost the same as in Example 1 and Comparative Example 1, respectively.

[0055]

[Table 3]

The following tests were carried out using these two kinds of dissolving / liquid adjusting liquids. 600 mL of MIBK and 200 mL of the dissolution / liquid adjustment liquid were placed in a separating funnel made of polymethylpentene, shaken with a shaker for 5 minutes, and allowed to stand for 10 minutes to extract an aqueous phase (extraction). 600 mL of water was put into the separating funnel where MIBK remained, shaken for 5 minutes, and allowed to stand for 10 minutes to extract the aqueous phase (back extraction). The same operation (extraction / back-extraction) was repeated using MIBK remaining in the separating funnel. If the amount of MIBK decreases on the way,
New MIBK was replenished. The number of repetitions was set to 100 times. However, the number of repetitions was set to one by performing extraction and back extraction as a set. Even if left for 10 minutes on the way, M
When the phase separation between the IBK phase and the aqueous phase became insufficient, the standing time was lengthened. When the same dissolving / liquid adjusting liquid as in Example 1 was used, there was no change in the phase separation state even after repeating 100 times, and the phase separation was sufficiently performed in about 3 minutes. When the same dissolving / liquid adjusting liquid as in Comparative Example 1 was used, the phase separation time was prolonged after about 50 times, and no phase separation was performed after 10 minutes after 92 times.

[0057]

As described above, according to the treatment method of the present invention, oil is dried from oil-containing sludge containing tantalum and / or niobium having a low content of tantalum and / or niobium and containing a large amount of oil. Removal by evaporation and suspension or dissolution in water or an organic solvent, or saponification can provide tantalum and / or niobium-containing raw materials suitable for efficient production of various products.

[Brief description of the drawings]

FIG. 1 is a process chart showing a method for treating tantalum and / or niobium-containing sludge of the present invention.

FIG. 2 is a process chart showing a method for producing tantalum oxide and niobium oxide by a hydrofluoric acid dissolution-solvent extraction method.

Continuation of the front page F term (reference) 4D059 AA10 BD00 BE01 BE31 BK12 CC07 DA01 DA35 DA38 DB01 DB02 4G048 AA02 AB08 AE02

Claims (8)

[Claims] 1. A step of extracting an oil-containing solid from an oil-containing sludge containing tantalum and / or niobium; a step of drying the extracted oil-containing solid to obtain a dry solid; A step of slurrying with a solvent and heating and stirring, and a step of solid-liquid separating the slurry after heating and stirring to obtain a tantalum and / or niobium-containing raw material from which oil has been removed. A method for treating an oil-containing sludge containing tantalum / niobium. 2. The method for treating an oil-containing sludge containing tantalum / niobium according to claim 1, wherein a sodium compound or a potassium compound is used in the drying step or the step of slurrying and heating and stirring. 3. The tantalum and / or the tantalum according to claim 2, wherein a sodium compound or a potassium compound is mixed with the oil-containing solid taken out and then dried.
Alternatively, a method for treating an oil-containing sludge containing niobium. 4. The method for treating tantalum / niobium-containing oil-containing sludge according to claim 3, wherein the sodium compound or the potassium compound is a carbonate or a bicarbonate. 5. The method for treating an oil-containing sludge containing tantalum / niobium according to claim 1, wherein the drying is performed at 150 to 300 ° C. 6. The method for treating an oil-containing sludge containing tantalum / niobium according to claim 1, wherein the heating and stirring are performed at 35 to 95 ° C. 7. The method for treating an oil-containing sludge containing tantalum / niobium according to claim 1, wherein a surfactant is used during the slurrying or the heating and stirring. . 8. In addition to the steps of the processing method according to claim 1, the tantalum and / or niobium-containing raw material from which the oil has been removed is treated with hydrofluoric acid or hydrofluoric acid and other minerals. A method for recovering tantalum / niobium, comprising a step of recovering tantalum and / or niobium in a hydrofluoric acid solution or a mixed acid solution by dissolving with a mixed acid with an acid.