JP2019528371A - Extraction method of rare metal element from coal ash and extraction device of rare metal element - Google Patents

Abstract

One embodiment of the present invention includes a first step of producing an extraction filtrate by reacting an extraction solvent containing a halogen acid with coal ash; adding a non-halogen acid extraction solvent to the extraction filtrate, and ultrasonic vibration. A second stage of reacting by adding a heat source; and a method for extracting a rare metal element. Thereby, this invention can extract yttrium (Y), neodymium (Nd), and gallium (Ga) with high efficiency from the coal ash which is electric power waste.

Description

  The present invention relates to a method for extracting a rare metal element from coal ash and an apparatus for extracting a rare metal element, and more particularly to a method for extracting a rare metal element containing rare earth elements from coal ash with high efficiency and an apparatus therefor. .

  Among chemical elements, metals can be classified into basic metals, noble metals, and rare metals according to normal standards. Among these, rare metals mean an element whose production volume is small compared to demand and where the production area is limited. Generally, gallium (Ga), lithium (Li), cobalt (Co) Various types of minerals including vanadium (V), nickel (Ni), zirconium (Zr), barium (Ba), neobium (Nb) and 17 rare earth metals are classified as rare metals.

  Among rare metals, elements belonging to rare earths are chemically stable and have a common feature of transferring heat well. Therefore, it is used mainly in advanced technology products such as ceramic functional materials, superconductors, heat-resistant alloys, solar materials, phosphors, magnetic materials, wind turbines, nuclear reactor structural materials and control agents, and electric vehicle materials. . In particular, the importance of such products is further emphasized because they are highly relevant to new growth power industries such as new renewable energy, LED application technology, and green aqueous systems.

  These rare metals, particularly rare earth metals, are characterized by their difficulty in smooth supply because their reserves and production are concentrated in some overseas countries. Along with this, in order to secure rare metals worldwide, efforts to develop sea deposits, river deposits, etc. into new deposits (or deposits) continue. Since the content is very low, it does not exert a great effect.

  In addition, conventional rare earth metals and rare metals containing them are generally used after quarrying raw ore at an overseas mine containing the resources, and then selectively extracting rare metals from them. In order to improve the quality of the quarried raw ore, it goes through processing processes such as crushing, heavy liquid, and sorting. However, the extraction efficiency is about 50% in the process of processing such raw material ore, and the remaining unrecovered elements are discarded in the form of by-products. In addition, the spatial difference between the mountain ore mine where raw material ore is mined and the central area where rare metals are treated is one of the causes of increased transportation, transportation and storage costs.

  On the other hand, coal ash belonging to electric power waste is known to contain various types of rare metals because of the characteristics of the substance, and has a characteristic of concentrating components present in coal.

  The amount of such coal ash is increasing every year due to an increase in power demand, etc., but there are not enough measures to treat it, and most of it is treated by landfill. Environmental problems such as land shortage are caused.

  Therefore, by developing a method to extract high-value-added rare metal elements from coal ash, the city mining business (a business that recycles and uses industrial waste in the city instead of mines in the mountainous area) is greatly developed. At the same time, there is an increasing demand for measures that create value that reduces the import dependency of rare metal elements and encourages the development of advanced industries.

  As a prior art related to the present invention, there is Korean Patent Publication No. 2017-0042661 (published on April 19, 2017, title of invention: method for extracting and separating rare earth elements).

  One object of the present invention is to provide a method and an apparatus for extracting a rare metal element including rare earth elements from coal ash with high efficiency.

  The above and other objects of the present invention can all be achieved by the present invention described below.

  One embodiment of the present invention includes a first step of producing an extraction filtrate by reacting an extraction solvent containing a halogen acid with coal ash; adding a non-halogen acid extraction solvent to the extraction filtrate, and ultrasonic vibration. A second stage of reacting by adding a heat source; and a method for extracting a rare metal element.

  In another embodiment of the present invention, an extraction solvent input port into which an extraction solvent containing a halogen acid is input and a coal ash input port into which coal ash is input are respectively formed at the upper portion, and includes the input halogen acid. A reactor for reacting the extraction solvent and coal ash; an ultrasonic generator that abuts on the outer wall of the reactor and provides ultrasonic vibration to the reactor; and formed at a lower portion of the outer wall of the reactor, The present invention relates to a rare metal element extraction apparatus comprising: a heating mantle for supplying heat; and an extract outlet formed at a lower portion of the reactor for discharging an extraction mixture from which the rare metal element is extracted.

  The present invention relates to a method for extracting a rare metal element capable of highly efficiently extracting rare metal elements including rare earth elements, particularly yttrium (Y), neodymium (Nd) and gallium (Ga) from coal ash which is power waste, and for the same Providing equipment.

FIG. 1 is a diagram showing a cross-sectional structure of an exemplary coal ash particle.
FIG. 2 is a view exemplarily illustrating the rare metal element extraction apparatus of the present invention.
FIG. 3 is a diagram exemplarily showing the structure of a reactor in the rare metal element extraction apparatus of the present invention.

Extraction Method of Rare Metal Element One embodiment of the present invention includes a first step of producing an extract filtrate by reacting an extraction solvent containing a halogen acid with coal ash; and adding a non-halogen acid extraction solvent to the extract filtrate. A second step of adding and reacting by adding an ultrasonic vibration heat source, and a method for extracting a rare metal element.

  Accordingly, the present invention can realize the effect of extracting rare metal elements including rare earth elements, particularly yttrium (Y), neodymium (Nd), and gallium (Ga) with high efficiency from coal ash that is power waste. it can.

  Specifically, the method for extracting a rare metal element of the present invention can embody the effect of significantly improving the extraction efficiency as compared with the conventional extraction method using raw material ore, which is about 1,000 ° C. or more. An effect of energy saving that can omit the raw material ore firing process can be realized, and there is an effect that the process of processing the toxic sulfide generated in the raw material ore processing process can be omitted.

  In addition, the method for extracting rare metal elements of the present invention has the effect of reducing the import dependency of raw ore that has been imported in its entirety by recycling coal ash that is power waste, reducing the amount of landfill. It contributes to solving the landfill shortage phenomenon, contributes to the development of urban mining business, and can reduce incidental costs such as transportation, transportation, storage, etc. ing.

  In the present specification, the rare metal element is not limited as long as it can be classified as a rare metal according to a general standard. However, the rare metal element is rare earth metal, gallium (Ga), lithium (Li), cobalt (Co), vanadium (V), nickel (Ni), zirconium (Zr), barium (Ba), or neobium (Nb). When 1 or more types are included, the improvement of the extraction efficiency by the extraction method of the rare metal element of this invention can further increase.

  In this specification, the rare earth elements are scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium. (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and ruthenium (Lu) .

  The rare metal element extraction method of the present invention includes, among the rare earth elements exemplified above, yttrium (Y) belonging to a heavy critical material that is expected to have a very low supply amount for medium to long-term demand. The extraction efficiency of neodymium (Nd) and the rare metal element gallium (Ga) can be extracted with high efficiency of about 98% or more of yttrium (Y), about 98% or more of neodymium (Nd) and about 90% or more of gallium (Ga). It can be implemented.

  The coal ash used as an extraction raw material in the present invention is not particularly limited. Specifically, the coal ash is fine particles generated when coal is burned at a high temperature in a furnace, and power waste generated by coal power generation or the like can be used. In this case, since the content of the rare metal element in the coal ash is high, the extraction efficiency by the extraction method of the rare metal element of the present invention can be further improved, and the economic effect by recycling the electric power waste is further improved. Yes.

  In addition, when using coal ash, which is a power waste, it can be immediately applied to the extraction method in the form of fine powder, so it can be used directly as a raw material for extraction by omitting mining, grinding, fine powder and sorting steps. The real advantage can be realized.

Illustratively, the coal ash may be crystallized after melting at a high temperature of about 1,200 ° C. to about 1,400 ° C. in a coal-fired power plant. Such coal ash generally contains a rare metal element in the form of Y ₂ O ₃ , Nd ₂ O _3, Ga ₂ O _3, etc., so among the rare metal elements, particularly yttrium (Y), The extraction efficiency of neodymium (Nd) and gallium (Ga) can be improved.

  The coal ash may be a sphere having an average particle size of about 15 μm to about 25 μm, for example. In this case, although the specific surface area of coal ash is large, the volumetric area is small, so that the extraction efficiency can be further improved.

  FIG. 1 schematically illustrates a cross-sectional structure of an exemplary coal ash particle. Referring to FIG. 1, the coal ash particles may include a surface layer A, a glassy structural layer B, and a crystalline structural layer C. The surface layer A, the vitreous structure layer B, and the crystalline structure layer C can be classified as follows, for example.

  The surface layer A means a layer in which rare metal elements are mixed on the surface of the vitreous structure without any particular structural limitation. The glassy structure layer B means a layer mainly containing a glassy structure in coal ash. The crystalline structure layer C means a layer mainly containing a crystalline structure in coal ash. In the description of the structure, the meaning of “mainly included layer” means that a specific structure is included with a numerical value of about 60% or more. The surface layer A, the vitreous structure layer B, and the crystalline structure layer C can be classified by, for example, a concentration gradient without a clear layer boundary.

Since various kinds of rare metal elements are mixed in the surface layer A without structural limitation, the aqueous solubility is high. In the vitreous structure layer B, the rare metal element is inserted into the vitreous structure formed of a substance other than the rare metal element contained in the coal ash, so that it has excellent aqueous and acidic dissolution characteristics. . In the crystalline structure layer C, a crystal structure formed of a substance other than the rare metal element in which the rare metal element is contained in coal ash (for example, malite (3Al ₂ O ₃ .2SiO ₂ ), quartz (SiO ₂ ) is formed. In general, the coal ash particles have a glassy state of about 20% by weight to about 40% by weight and a crystalline state of about 60% by weight. It may be contained at about 80% by weight.

  Such a structural difference of coal ash particles may be a factor that reduces the utility in the conventional coal ash recycling method. However, the rare element extraction method of the present invention uses the surface layer A and the surface layer A in the first stage described above. The rare metal element contained in the glassy structural layer B was effectively extracted, and the insoluble rare metal element present in the crystalline structural layer C was converted to water-soluble, and converted to water-soluble in the second stage. Extraction efficiency can be further improved by efficiently separating and extracting rare metal elements.

In the first step, an extraction filtrate containing a halogen acid is reacted with coal ash to produce an extraction filtrate. This makes it possible to extract a rare metal element from coal ash with high efficiency and to dissolve an insoluble structure in which rare metal elements such as Y ₂ O ₃ , Nd ₂ O ₃ and Ga ₂ O ₃ are combined with mullite and quartz. Can be converted into a structure.

  Specifically, the halogen acid may include a compound represented by the following chemical formula 1 or chemical formula 2.

[Chemical Formula 1]
HXOn

[Chemical formula 2]
HX

  In Formulas 1 and 2, X is a halogen atom, and n is an integer of 1 to 5.

  The halogen acid is a strong acid composed of a complex ion of a halogen element (for example, F, Cl, Br, I, etc.) and a hydrogen ion, and is excellent in the degree of stabilization of the produced halogen complex ion, and has a wide range of anions. Distributed (unevenly distributed). Thereby, the crystal lattice structure in coal ash, which has been difficult to dissolve by conventional strong acids such as sulfuric acid and nitric acid, can be changed, and the insoluble structure combined with mullite and quartz can be converted into a water-soluble structure.

  The halogen acid can react with coal ash to convert an insoluble structure combined with mullite, quartz, etc. into a water-soluble structure, for example, according to the principle of the following reaction formula 1.

[Reaction Formula 1]
(1a) (Y ₂ O ₃ .3Al ₂ O ₃ .2SiO ₂ ) (22SiO ₂ ) + [HX or HXOn] + H ₂ O (aq) → (Y ₂ O ₃ .3Al ₂ O ₃ .12SiO ₂ ) + 12SiO ₂ + H ₂ O (g) ↑
(1b) (Nd ₂ O ₃ .3Al ₂ O ₃ .2SiO ₂ ) (22SiO ₂ ) + [HX or HXOn] + H ₂ O (aq) → (Nd ₂ O ₃ .3Al ₂ O ₃ .12SiO ₂ ) + 12SiO ₂ + H ₂ O (g) ↑
(1c) (Ga ₂ O ₃ .3Al ₂ O ₃ .2SiO ₂ ) (22SiO ₂ ) + [HX or HXOn] + H ₂ O (aq) → (Ga ₂ O ₃ .3Al ₂ O ₃ .12SiO ₂ ) + 12SiO ₂ + H ₂ O (g) ↑

As shown in Reaction Scheme 1, halogen acids are insoluble structures (Y ₂ O ₃ .3Al ₂ O ₃ .2SiO ₂ ) (22SiO ₂ ), (Nd ₂ O ₃ .3Al ₂ O) bonded to mullite and quartz. _{3 · 2SiO 2) (22SiO 2} ), (Ga 2 O 3 · 3Al 2 O 3 · 2SiO 2) (22SiO 2) a water-soluble structural _{(Y 2 O 3 · 3Al 2} O 3 · 12SiO 2), (Nd ₂ O ₃ .3Al ₂ O ₃ .12SiO ₂ ), (Ga ₂ O ₃ .3Al ₂ O ₃ .12SiO ₂ ) and free quartz (Free quartz, 12SiO ₂ ). Thereby, the extraction efficiency of yttrium (Y), neodymium (Nd), and gallium (Ga) can be further increased.

  Although the reaction formula 1 is described only for yttrium (Y), neodymium (Nd), and gallium (Ga), it can be applied without being limited to the kind of rare metal element.

  More specifically, the extraction solvent containing the halogen acid may be a mixed solution of hydrofluoric acid (HF), hydrofluoric acid (HF), and the halogen acid of formula 1 (HXOn). In this case, the degree of stabilization of the halogen acid complex ion is further excellent, and the effect of widely dispersing (undistributed) anions is further excellent.

Specifically, the extraction solvent containing the halogen acid may further include one or more of nitric acid (HNO ₃ ) and hydrochloric acid (HCl). In this case, the extraction efficiency of various kinds of rare metal elements can be further improved.

More specifically, the extraction solvent containing the halogen acid may be a mixed solution of hydrofluoric acid (HF), perchloric acid (HClO ₄ ), nitric acid (HNO ₃ ), and hydrochloric acid (HCl). In this case, the effect of converting the insoluble structure combined with mullite and quartz to a water-soluble structure is improved by changing the crystal lattice structure of the crystalline structure, which was difficult to dissolve with strong acids such as sulfuric acid and nitric acid. can do.

More specifically, the extraction solvent containing the halogen acid is about 1M to about 28M hydrofluoric acid (HF), about 1.5M to about 8M perchloric acid (HClO ₄ ), and about 0 nitric acid (HNO ₃ ). 0.5M to about 15M and hydrochloric acid (HCl) can be included at about 1M to about 16M. In this case, it is possible to further improve the effect of changing the crystal lattice structure of the crystalline structure to convert the insoluble structure combined with mullite and quartz into a water-soluble structure, particularly yttrium (Y) and neodymium (Nd). In addition, the extraction efficiency of gallium (Ga) can be significantly improved.

More specifically, the extraction solvent containing the halogen acid includes about 3.4 to 14.0: about 1 hydrofluoric acid (HF), perchloric acid (HClO ₄ ), nitric acid (HNO ₃ ), and hydrochloric acid (HCl). 4 to 6.0: about 1.9 to 8.0: about 1.5 to 6.1. In this case, it is possible to further improve the effect of changing the crystal lattice structure of the crystalline structure to convert the insoluble structure combined with mullite and quartz into a water-soluble structure, particularly yttrium (Y) and neodymium (Nd). In addition, the extraction efficiency of gallium (Ga) can be significantly improved.

In one specific example, the halogenated acid-containing extraction solvent includes hydrofluoric acid (HF) of about 3.45M to about 13.79M, perchloric acid (HClO ₄ ) of about 1.45M to about 5.8M, nitric acid (HNO ₃ ) About 1.96M to about 7.85M and hydrochloric acid (HCl) about 1.52M to about 6.09M. In this case, the extraction efficiency of yttrium (Y), neodymium (Nd), and gallium (Ga) can be further improved.

In another embodiment, the extraction solvent containing the halogen acid is aqua regia mixed with HCl: HNO ₃ = about 3: 1 and halogen acid based on a volume ratio, and aqua regia: HF: HClO ₄ = about 4: 1. : 1 may be used. In this case, the extraction efficiency of yttrium (Y), neodymium (Nd), and gallium (Ga) can be further improved.

  Specifically, the solid-liquid ratio of the extraction solvent containing halogen acid and the coal ash in the first step may be about 10 g / L to about 50 g / L. The gram (g) unit means the weight of coal ash, and the liter (L) unit means the volume of halogen acid. The effect of converting the insoluble structure into the water-soluble structure within the above range can be further improved, and the extraction efficiency of the rare metal element can be further improved.

Specifically, the reaction temperature may be about 150 ° C. to about 300 ° C. in the first step. Within the above range, the effect of converting the insoluble structure into the water-soluble structure can be further improved, the extraction efficiency of the rare metal element can be further improved, and the H ₂ O (g ) Can also be evaporated.

  Further, the method for extracting a rare metal element of the present invention within the above temperature range omits the high-temperature extraction step of about 1,000 ° C. or more required in the step of extracting the conventional raw material ore, but about 150 ° C. to about 150 ° C. Excellent extraction efficiency can be realized in a relatively low temperature range of 300 ° C.

  Specifically, the reaction time in the first stage may be about 0.5 hours (h) to about 1.5 hours (h). Within the above range, the extraction efficiency of the rare metal element can be further improved, and the economic efficiency can be further improved by improving the process efficiency.

  In one specific example, the first stage is carried out under the conditions that the solid-liquid ratio is about 16.7 g (coal ash) / 1 L (halogen acid), the reaction temperature is about 250 ° C., and the reaction time is about 1 h. After the water is evaporated and discharged, the remaining extract filtrate can be used as a raw material in the second stage described later. In this case, the effect of converting the insoluble structure into the water-soluble structure can be further improved, and the extraction efficiency of the rare metal element can be further improved.

In the second stage, a non-halogen acid extraction solvent is added to the extraction filtrate, and the reaction is performed by heating with a heat source. Thus, (Y ₂ O ₃ .3Al ₂ O ₃ .12SiO ₂ ), (Nd ₂ O ₃ .3Al ₂ O ₃ .12SiO ₂ ), (Ga ₂ O _3. Rare metal element ions can be leached with high efficiency of about 60% or more from the rare metal element converted to 3Al ₂ O ₃ · 12SiO ₂ ) or the like.

The extracted filtrate reacts with a non-halogen acid extraction solvent in the presence of a heat source to leach trivalent rare metal element ions (Y ³⁺ , Nd ³⁺ , Ga ³⁺ ) on the principle of the following reaction formula 2, for example. To do.

[Reaction Formula 2]
(2a) (Y ₂ O ₃ .3Al ₂ O ₃ .12SiO ₂ ) (NO ₃ ) ₂ + HNO ₃ + 6H ₂ O → H ⁺ + Y ³⁺ + NO ₃ ² + + 6H ₂ O
(2b) (Nd ₂ O ₃ .3Al ₂ O ₃ .12SiO ₂ ) (NO ₃ ) ₂ + HNO ₃ + 6H ₂ O → H ⁺ + Nd ³⁺ + NO ₃ ² + + 6H ₂ O
(2c) (Ga ₂ O ₃ .3Al ₂ O ₃ .12SiO ₂ ) (NO ₃ ) ₂ + HNO ₃ + 6H ₂ O → H ⁺ + Ga ³⁺ + NO ₃ ² + + 6H ₂ O

As shown in Reaction Scheme 2, the extracted filtrate reacts with a non-halogen acid extraction solvent in the presence of a heat source to form (Y ₂ O ₃ .3Al ₂ O ₃ .12SiO ₂ ), (Nd ₂ O) having a water-soluble structure. It is possible to leach rare metal element ions (Y ³⁺ , Nd ³⁺ , Ga ³⁺ ) with high efficiency from ( ₃ · 3Al ₂ O ₃ · 12SiO ₂ ) and (Ga ₂ O ₃ · 3Al ₂ O ₃ · 12SiO ₂ ). Thereby, the extraction efficiency of yttrium (Y), neodymium (Nd), and gallium (Ga) can be further increased.

  Although the reaction formula 2 is described only for yttrium (Y), neodymium (Nd), and gallium (Ga), it can be applied without being limited to the kind of rare metal element.

The non-halogen acid extraction solvent means an acidic solvent containing no halogen acid. Specifically, the non-halogen acid extraction solvent may include nitric acid (HNO ₃ ). In this case, the extraction efficiency of various kinds of rare metal elements can be further improved.

In one embodiment, the non-halogen acid extraction solvent may include nitric acid (HNO ₃ ) at about 1.12M to about 2.24M.

In another embodiment, the non-halogen acid extraction solvent may include nitric acid (HNO ₃ ) at a concentration of about 1.12M to about 2.24M, and the input amount in the second stage is used in the first stage. The volume ratio of the extraction solvent containing the halogen acid may be about 1: 1. In this case, in particular, the extraction efficiency of yttrium (Y), neodymium (Nd), and gallium (Ga) can be further improved.

Specifically, the heat source may include one or more of a heating mantle and an ultrasonic generator. Thus, the water-soluble structures _{(Y 2 O 3 · 3Al 2} O 3 · 12SiO 2), (Nd 2 O 3 · 3Al 2 O 3 · 12SiO 2), (Ga 2 O 3 · 3Al 2 O 3 · 12SiO 2 ) Can be further leached with rare metal element ions (Y ³⁺ , Nd ³⁺ , Ga ³⁺ ).

  In one specific example, when a heating mantle is used as a heat source, the extraction efficiency of various kinds of rare metal elements can be further improved. In this case, the extraction efficiency of various kinds of rare metal elements can be improved, and in particular, the extraction efficiency of yttrium (Y), neodymium (Nd), and gallium (Ga) can be improved.

  In another embodiment, when an ultrasonic generator is used as a heat source, the extraction efficiency of various kinds of rare metal elements can be further improved, particularly yttrium (Y), neodymium (Nd), and gallium (Ga). Can be significantly improved to about 99% or more. In this case, the ultrasonic wave applied via the ultrasonic generator is in the form of a longitudinal wave on the gas, but can be a transverse wave or a shear wave in the liquid and solid. The ultrasonic generator can further improve the leaching rate by converting a high-frequency alternating magnetic field or current into mechanical vibration via a magnetic deformation conversion method or a piezoelectric conversion method, for example. In the above example, the applied ultrasound may be high power or low power ultrasound.

  At this time, when an ultrasonic wave having a large amplitude is added to the extraction filtrate in the second stage, the liquid generates bubbles, which can generate shock wave energy that induces rapid flow and shear pressure. By applying shear wave impact energy to the compound having a water-soluble structure contained in the extraction filtrate, the ionization rate and extraction efficiency of the rare metal element can be further increased. The frequency of the ultrasonic wave may be, for example, about 20 kHz to about 100 kHz. Within the above range, the ionization degree and extraction efficiency of the rare metal element can be further increased.

  Specifically, the liquid-liquid ratio of the extraction filtrate and the non-halogen acid extraction solvent in the second step may be about 0.8 ml / ml to about 1.2 ml / ml. The milliliter (ml) unit at the molecular position means the volume of the extracted filtrate, and the milliliter (ml) unit at the denominator position means the volume of the non-halogen acid extraction solvent. Within the above range, the extraction efficiency of the rare metal element can be further improved.

  The reaction temperature in the second step may be about 50 ° C. to about 200 ° C., specifically about 60 ° C. to about 90 ° C. Within the above range, the extraction efficiency of the rare metal element can be further improved.

  Specifically, the reaction time in the second stage may be about 1.5 hours (h) to about 2.5 hours (h). Within the above range, the extraction efficiency of the rare metal element can be further improved, and the economic efficiency can be further improved by improving the process efficiency.

  The method for extracting a rare metal element of the present invention may further include a third step of separating the rare metal element from the product of the second step.

  The method for separating the rare metal element is not particularly limited, but may be performed by the following process as an example.

  Specifically, ionized rare metal element ions contained in the rare metal element leaching solution, which is the product of the second stage, can be adsorbed and separated by an organic adsorbent using the organic selectivity of each ion. .

  More specifically, the rare metal element ion may be converted into an organic adsorbed floating substance by contacting with kerosene, which is an organic adsorbing material. The organic adsorbed suspension can selectively desorb or precipitate the target ions in the form of a compound by contacting with a specific solvent depending on the selectivity and solubility of each metal element ion.

In one specific example, the organic adsorbed suspended matter is reacted with sulfuric acid to desorb Y ³⁺ ions having high selectivity with sulfuric acid according to the principle of the following chemical formula 3, and the desorbed Y ³⁺ ion solution is converted to oxalic acid. After reacting and converting to a yttrium oxalic acid precipitate, it can be filtered and dried, and then heated at about 950 ° C. to about 1,000 ° C. in an air atmosphere to crystallize into Y ₂ O ₃ .

[Reaction Formula 3]
(3a) Kerosene− (Y ³⁺ , Nd ³⁺ , Ga ³⁺ ) (s) + H ₂ SO ₄ → Kerosene− (Nd ³⁺ , Ga ³⁺ ) (s) + Y ³⁺ + SO ₄ ²⁻
(3b) 4Y ³⁺ +6 (C ₂ O ₄ ) ^{2 −} → 2Y ₂ (C ₂ O ₄ ) ₃
(3c) Y ₂ (C ₂ O ₄ ) ₃ + O ₂ → Y ₂ O ₃ ↓ + H ₂ O + CO ₂

In another specific example, the organic adsorbed suspended matter is reacted with hydrochloric acid to desorb Nd ³⁺ ions having high selectivity with hydrochloric acid according to the principle of the following chemical formula 4, and the desorbed Nd ³⁺ ion solution is washed. It can be crystallized into Y ₂ O ₃ by reacting with an acid to convert it into a yttrium oxalic acid precipitate, followed by filtration and drying, followed by heating at about 950 ° C. to about 1,000 ° C. in an air atmosphere. .

[Reaction Formula 4]
(4a) Kerosene− (Y ³⁺ , Nd ³⁺ , Ga ³⁺ ) (s) + HCl → Kerosene− (Y ³⁺ , Ga ³⁺ ) (s) + Nd ³⁺ + SO ₄ ²⁻
(4b) 4Nd ³⁺ +6 (C ₂ O ₄ ) ^{2 −} → 2Nd ₂ (C ₂ O ₄ ) ₃
(4c) Nd ₂ (C ₂ O ₄ ) ₃ + O ₂ → Nd ₂ O ₃ ↓ + H ₂ O + CO ₂

In still another specific example, the organic adsorbed suspension is reacted with nitric acid to desorb Ga ³⁺ ions having high selectivity with nitric acid according to the principle of the following chemical formula 5, and the desorbed Ga ³⁺ ion solution is It can be converted to yttrium oxalic acid precipitate by reacting with oxalic acid, filtered and dried, and then heated at about 950 ° C. to about 1,000 ° C. in an air atmosphere to crystallize into Ga ₂ O _3. it can.

[Reaction Formula 5]
(5a) Kerosene− (Y ³⁺ , Nd ³⁺ , Ga ³⁺ ) (s) + HNO ₃ → Kerosene− (Y ³⁺ , Nd ³⁺ ) (s) + Ga ³⁺ + SO ₄ ²⁻
(5b) 4Ga ³⁺ +6 (C ₂ O ₄ ) ^{2 −} → 2Ga ₂ (C ₂ O ₄ ) ₃
(5c) Ga ₂ (C ₂ O ₄ ) ₃ + O ₂ → Ga ₂ O ₃ ↓ + H ₂ O + CO ₂

  Although the reaction formulas 3 to 5 are described only for yttrium (Y), neodymium (Nd), and gallium (Ga) by way of example, they can be applied without being limited to the kind of rare metal element.

  In addition, before the third stage of separating the rare metal element from the product of the second stage, the rare metal element leachate as the second stage product is separated into a solid coal ash residue and a liquid rare metal element ionic liquid. Can be further performed.

  The separation method is not particularly limited. For example, the rare metal element leachate as the second stage product is passed through a solid-liquid separator to be separated into a solid coal ash residue and a liquid rare metal element ionic liquid. It may be a thing.

Rare metal element extraction device Another embodiment of the present invention is formed with an extraction solvent inlet into which an extraction solvent containing a halogen acid is introduced and a coal ash inlet into which coal ash is introduced, respectively. A reactor for reacting the extracted halogen-containing extraction solvent with coal ash; an ultrasonic generator that abuts the outer wall of the reactor and provides ultrasonic vibration to the reactor; and a lower portion of the outer wall of the reactor; A heating mantle formed and supplying heat to the reactor; and an extraction outlet formed at a lower portion of the reactor for discharging an extraction mixture from which the rare metal element is extracted. .

  Each component included in the rare metal element extraction apparatus is not particularly limited as long as it performs the same function without hindering the execution of the rare metal element extraction method described above.

  FIG. 2 is an exemplary diagram of the rare metal element extraction apparatus of the present invention. Referring to FIG. 2, the rare metal element extraction apparatus includes a hydrochloric acid tank 1, a nitric acid tank 2, a hydrofluoric acid tank 3, and a perchloric acid tank 4 as reservoirs, and hydrochloric acid 1 and nitric acid 2 as mixers. Aqua regia production tank 5 for producing aqua regia by mixing together, aqua regia production tank 5, hydrofluoric acid tank 3, and perchloric acid tank 4, and halogen acid extraction transferred from the respective reservoirs or mixers An extraction solvent supply unit including a mixing tank 6 for mixing the solvent and the non-halogen acid extraction solvent; a reaction unit including a reactor 8 including a heating mantle and an ultrasonic generator as a heat source device; and rare from the reactor 8 A rare metal element including a primary solid-liquid separator 12 which is supplied with a metal element leachate and separates into a solid and a liquid and obtains a rare metal ionic liquid from which the solid has been removed through the solid-liquid separator 12 And a release portion; may further include a.

  More specifically, the rare metal element extraction apparatus includes a hydrochloric acid tank 1, a nitric acid tank 2, an aqua regia production tank 5 that mixes aqua regia through a chemical reaction of hydrochloric acid 1 and nitric acid 2, aqua regia 5 and halogen. It comprises a hydrofluoric acid tank 3 for making an acid mixture, a perchloric acid tank 4, and a mixing tank 6 for producing a complex halogen acid by mixing aqua regia 5, hydrofluoric acid 3 and perchloric acid 4. The acid is transferred from the tank containing each acid to the mixer via the extraction solvent supply unit, mixed according to the target concentration, and supplied to the reaction unit. At this time, the mixing of the acids is performed as described in the method for extracting a rare metal element. The reaction section includes a coal ash raw material tank 7; a steam condenser 9 that captures and condenses vapor vaporized during the reaction in the reactor 8, and a water tank that dilutes the concentration of nitric acid 2 further supplied to the reactor. 10 and a nitric acid dilution tank 11 that mixes and dilutes the water 10 and nitric acid 2 to further dilute the water, the water captured by the steam condenser 9 and the water stored in the water tank 10. Is adjusted to the concentration of the non-halogen acid extraction solvent that is transferred to the nitric acid dilution tank 11 and charged into the second stage reaction.

  The rare metal element separation unit transfers the produced rare metal element leaching solution from the reactor 8 after the first stage and second stage reactions of the metal element extraction method described above are completed, and the coal ash is solid. A primary solid-liquid separator 12 that separates the residue by filtration, a coal ash extraction residue tank 13 that stores solids separated by the primary solid-liquid separator 12, and an extraction residue that cleans the extraction solvent remaining in the coal ash extraction residue 13 Washer 14, water tank 10 for supplying water to extraction residue cleaner 14, secondary solid-liquid separator 15 that separates the water remaining in the washed extraction residue from the washed extraction residue, and secondary solid-liquid An extraction residue water dehydrator 16 for dehydrating a small amount of water remaining in the separator 15 and a weakly acidic aqueous solution generated in the secondary solid-liquid separator 15 and the washing extraction residue dewaterer 16 are connected to the subsequent stage of the mixing tank 6. And then recycled to reactor 8 A circulation device for the washing extraction residue dewatered in the washing extraction residue 渣脱 condenser 16 may further include a coal Haizann 渣貯 built 18 for storing the residue moisture has been removed by the drier 17.

The rare metal element separation unit can selectively adsorb only ions from the rare metal element ionic liquid storage tank 20 separated by the primary solid-liquid separator 12; and the ionic liquid supplied from the ionic liquid storage tank 20. An ion adsorbent reservoir 19 for supplying kerosene as an organic adsorption solvent, an aggregate storage tank 22 for storing aggregates 22 adsorbed by kerosene in an ionic liquid storage tank 20, and yttrium ions in the aggregates 22. A sulfuric acid storage tank 21 for supplying sulfuric acid excellent in selective desorption performance with respect to yttrium in order to desorb only (Y ³⁺ ) with ions, and a precipitation liquid for separating the aggregate and desorbed yttrium ionic liquid (Y ³⁺ ). Yttrium ionic liquid storage, storing yttrium ionic liquid separated by solid-liquid separator A tank 25, an oxalic acid storage tank 24 for supplying oxidized precipitation acid to precipitate yttrium in the yttrium ionic liquid storage tank 25, an yttrium oxalic acid precipitate storage tank 26 precipitated in the yttrium ionic liquid storage tank 25, and yttrium. A calciner 27 for producing yttrium oxide powder (Y ₂ O ₃ ) through thermal oxidation of the yttrium oxalic acid precipitate transported in the oxalic acid precipitate storage tank 26 and a yttrium oxide product powder produced in the calciner 27 are stored. Yttrium oxide product storage tank 28, hydrochloric acid storage tank 1 for supplying dilute hydrochloric acid with high neodymium desorption selectivity to desorb neodymium out of the precipitated organic rare earth separated by solid-liquid separator 23, and water for dilution Desorbed in the water storage tank 10 and the organic rare earth storage tank 29 Organic substances separating neodymium ion (Nd ³⁺ ) and organic kerosene, neodymium ion separator 30, washing machine 31 washing organic kerosene separated by neodymium ion separator 30, and kerosene washed by washing machine 31 are kerosene storage tanks. A neodymium ionic liquid storage tank 32 for storing neodymium ions (Nd ³⁺ ) separated by the neodymium ion solid-liquid separator 30, and a neodymium ionic liquid storage tank. An oxalic acid storage tank 24 that supplies oxalic acid to synthesize neodymium oxalic acid precipitate in the tank 32, and a neodymium precipitate storage tank 33 that performs a precipitation reaction between oxalic acid and neodymium supplied in the oxalic acid storage tank 24. And neodymium oxalate precipitates precipitated in the neodymium precipitate storage tank 33 are converted to neodymium oxide (Nd ₂ O ₃ ) A calciner 34 for heating and oxidizing the product and a neodymium oxide storage tank 35 for storing the neodymium oxide product powder heated and oxidized by the calciner 34 may be further included. The separation order of each rare metal element in the rare metal element separation unit may be changed according to the characteristics of each element.

  FIG. 3 is a diagram exemplarily showing the structure of a reactor in the rare metal element extraction apparatus of the present invention. Referring to FIG. 3, the reactor 8 has an outer wall 8-1, an upper plate 8-2 that covers the upper portion of the outer wall 8-1, and high acid resistance and heat resistance fixed inside the reactor 8. A Teflon (Registered Trademark) material reactor 8-3, a Teflon (Registered Trademark) reactor upper plate 8-4 for preventing leakage of reactants inside the Teflon (Registered Trademark) reactor, and Teflon An ultrasonic generator 8-5 for supplying ultrasonic waves to the (registered trademark) reactor 8-3, a heating mantle 8-6 for supplying heat to the Teflon (registered trademark) reactor 8-3, and an ultrasonic reaction A heat insulating material 8-7 for maintaining heat insulation between the vessel 8-5 and the heating mantle 8-6, a coal ash inlet 8-8 for supplying coal ash to the Teflon (registered trademark) reactor 8-3, a reaction 8-9 for introducing the extraction solvent necessary for the test, and a Teflon (registered trademark) reactor 8 When a high pressure is formed in 3, the safety valve 8-10 that adjusts the pressure to prevent explosion, and the temperature of the reaction water mixed with coal ash and extraction solvent in the Teflon (registered trademark) reactor 8-3 are measured. An infrared thermometer 8-11 for controlling the power supply, a connecting bolt 8-12 for connecting the outer wall 8-1 and the upper plate 8-2, a Teflon (registered trademark) reactor 8-3 and a Teflon (registered trademark). ) A Teflon (registered trademark) reactor leakage prevention ring 8-14 for connecting the reactor upper plate 8-13, a discharge port 8-15 for discharging a rare metal element leachate in the Teflon (registered trademark) reactor 8-3, , Passing through a steam discharge port 8-16 for discharging steam generated in the reactor, a steam discharge control valve 8-17 for controlling the amount of steam generated at the steam discharge port 8-16, and a steam discharge control valve 8-17 A condenser 9-1 for condensing steam to be condensed with water; The cooling water needed for the condenser may include a cooling water inlet 9-2 supplies.

  In one embodiment, the reactor material may be Teflon (registered trademark) having a thickness of about 5 mm or more excellent in acid resistance and heat resistance, and an infrared thermometer is used instead of a metal thermometer. When used, corrosion due to contact with acid can be prevented.

  Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and should not be construed as limiting the present invention in any way.

Examples Preparation Example 1: Preparation of coal ash Coal ash, which is a power waste, is fly ash powder and has a content of rare metal elements described in Table 1 below and has an average particle size of 25 μm or less in the form of fine powder. Coal ash was prepared.

Examples 1-3
First stage: After charging coal ash into the reactor, the reaction was advanced after adding an extraction solvent having the composition according to Table 2 below. The reaction was carried out under the conditions that the solid-liquid ratio of coal ash and the extraction solvent was 16.7 g ash / 1 L extraction solvent, the reaction temperature was 250 ° C., and the reaction time was 1 h.
Second stage: A non-halogen acid extraction solvent having the composition shown in Table 3 below was added to the extracted filtrate, and the reaction was advanced by heating with an electric heater. The liquid / liquid ratio of the extracted filtrate to the non-halogen acid extraction solvent was 1 ml of the extract filtrate / 1 ml of the non-halogen acid extraction solvent, the reaction temperature was 80 ° C., and the reaction time was 2 hours.

Comparative Examples 1-5
First stage: After charging coal ash into the reactor, the reaction was allowed to proceed after adding an extraction solvent having the composition according to Table 2 below. The reaction was carried out under the conditions that the solid-liquid ratio of coal ash and the extraction solvent was 16.7 g ash / 1 L extraction solvent, the reaction temperature was 80 ° C. to 95 ° C., and the reaction time was 6 h.
Second stage: not done

Comparative Examples 6-25
First stage: After charging coal ash into the reactor, the reaction was allowed to proceed after adding an extraction solvent having the composition according to Table 2 below. The reaction was carried out under the conditions that the solid-liquid ratio of coal ash and the extraction solvent was 16.7 g ash / 1 L extraction solvent, the reaction temperature was 250 ° C., and the reaction time was 1 h.
Second stage: The extraction solvent having the composition shown in Table 3 below was added to the extracted filtrate, and the reaction was advanced by heating with an electric heater. The reaction was carried out under the conditions described in Table 3 below for the liquid-liquid ratio of the extraction filtrate to the non-halogen acid extraction solvent, the reaction temperature, and the reaction time.

  Extracting the content of rare metal elements leached from the extracts of Examples and Comparative Examples, and measuring the extraction efficiency based on the content contained in coal ash before the reaction was carried out, the following Table 4 It was shown to.

  As can be seen from Table 4, the first step of producing an extract filtrate by reacting an extraction solvent containing a halogen acid and coal ash; adding a non-halogen acid extraction solvent to the extract filtrate, and ultrasonic vibration Examples 1 to 3 in which a rare metal element was extracted by a method including a second stage of reacting by adding a heat source, were all gallium (Ga), lithium (Li), cobalt (Co), vanadium (V), Excellent extraction efficiency was demonstrated for nickel (Ni), zirconium (Zr), barium (Ba) and neobium (Nb).

  In Examples 1 to 3 of the present invention, in particular, the extraction efficiency of yttrium (Y) and neodymium (Nd) and the rare metal element gallium (Ga) is 98% or more of yttrium (Y), 98% or more of neodymium (Nd), and gallium. (Ga) The effect of extracting with high efficiency of 90% or more was realized.

  Simple variations or modifications of the present invention can be easily implemented by those having ordinary knowledge in this field, and any such modifications or changes can be considered as being included in the scope of the present invention.

1 hydrochloric acid tank 2 nitric acid tank 3 hydrofluoric acid tank 4 perchloric acid tank 5 aqua regia production tank 6 mixing tank 7 coal ash raw material tank 8 reactor 8-1 outer wall 8-2 upper plate 8-3 Teflon (registered trademark) Reactor 8-4 Reactor upper plate made of Teflon (registered trademark) 8-5 Ultrasonic generator 8-6 Heating mantle 8-7 Heat insulating material 8-8 Coal ash inlet 8-9 Extraction solvent inlet 8- 10 Safety valve 8-11 Infrared thermometer 8-12 Connection bolt 8-13 Reactor upper plate 8-14 Teflon (registered trademark) reactor leakage prevention ring 8-15 Leachate discharge port 8-16 Steam discharge port 8-17 Steam discharge Control valve 9 Steam condenser 9-1 Condenser 9-2 Cooling water inlet 9-3 Cooling water outlet 9-4 Condensate outlet 10 Water tank 11 Nitric acid dilution tank 12 Primary solid-liquid separator 13 Coal ash extraction residue Residual tank 14 Extraction residue cleaner 15 Secondary solid-liquid separator 16 Residue dewatering device 17 Residue cleaning coal ash dryer 18 Residue reservoir 19 Ion adsorbate reservoir 20 Ionic liquid storage tank 21 Sulfuric acid storage tank 24 Oxalic acid storage tank 25 Yttrium ionic liquid storage tank 26 Yttrium oxalic acid precipitate storage tank 27 Baking device 28 Yttrium oxide product storage tank 29 Neodymium adsorption organic rare earth storage tank 30 Organic matter separator 31 Organic matter cleaning device 32 Neodymium ion liquid storage tank 33 Neodymium precipitate storage tank 34 Firing machine 35 Neodymium oxide powder

Claims (11)

A first stage in which an extraction solvent containing a halogen acid is reacted with coal ash to produce an extract filtrate;
A second step of adding a non-halogen acid extraction solvent to the extraction filtrate and reacting by adding an ultrasonic vibration heat source, and extracting the rare metal element. 2. The extraction of a rare metal element according to claim 1, wherein the extraction solvent containing a halogen acid is a mixed solution of hydrofluoric acid (HF), perchloric acid (HClO ₄ ), nitric acid (HNO ₃ ), and hydrochloric acid (HCl). Method. As the extraction solvent containing the halogen acid, hydrofluoric acid (HF), perchloric acid (HClO ₄ ), nitric acid (HNO ₃ ) and hydrochloric acid (HCl) are about 3.4 to 14.0: about 1.4 to 6. The method for extracting a rare metal element according to claim 2, wherein the extraction is performed at a molar ratio of 0: about 1.9 to 8.0: about 1.5 to 6.1.   The method for extracting a rare metal element according to claim 1, wherein coal ash is blended at about 10 g to about 50 g per liter of extraction solvent containing halogen acid in the first stage.   The method for extracting a rare metal element according to claim 1, wherein the reaction temperature in the first stage is about 150C to about 300C. The method for extracting a rare metal element according to claim 1, wherein the non-halogen acid extraction solvent is nitric acid (HNO ₃ ).   2. The method for extracting a rare metal element according to claim 1, wherein in the second stage, the ultrasonic frequency is about 20 kHz to about 100 kHz and the reaction temperature is about 60 ° C. to about 90 ° C. 3.   The rare metal element according to claim 1, wherein the extraction efficiency of the rare metal element extraction method is about 98% or more of yttrium (Y), about 98% or more of neodymium (Nd) and about 90% or more of gallium (Ga). Extraction method.   The method for extracting a rare metal element according to claim 1, wherein the volume ratio of the extraction filtrate to the non-halogen acid extraction solvent in the second stage is about 0.8: 1 to about 1.2: 1.   The rare metal elements are scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu). , Gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and ruthenium (Lu), gallium (Ga), lithium (Li) Extraction of a rare metal element according to claim 1, comprising at least one of cobalt, cobalt (Co), vanadium (V), nickel (Ni), zirconium (Zr), barium (Ba) and neobium (Nb) Method. An extraction solvent input port into which an extraction solvent containing halogen acid is added and a coal ash input port into which coal ash is supplied are formed at the top, respectively, and a reaction in which the extracted solvent containing halogen acid is reacted with coal ash With a vessel;
An ultrasonic generator that abuts the outer wall of the reactor and provides ultrasonic vibrations to the reactor;
A heating mantle formed at a lower portion of the outer wall of the reactor and supplying heat to the reactor;
An extractor for a rare metal element, which is formed in the lower part of the reactor and includes an extract outlet for discharging an extraction mixture from which the rare metal element is extracted.

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