CN115198311B - Gallium extract, preparation method and preparation system of gallium extract, and gallium purification method and purification system - Google Patents

Abstract

The invention provides a gallium extract, a preparation method and a preparation system of the gallium extract, a gallium purification method and a gallium purification system, and relates to the technical field of crystal growth. In the preparation method of the gallium extract, the gallium extract is from furnace dust of a single crystal furnace. The gallium extract is from the furnace ash of the single crystal furnace, rather than extracting gallium from gallium-containing ores, so that gallium resources are prevented from being reduced, the secondary utilization of the furnace ash of the single crystal furnace is realized, and resource waste is reduced.

Description

Gallium extract, gallium extract preparation method and preparation system, gallium purification method and purification system

Technical Field

The invention relates to the technical field of crystal growth, and in particular to a gallium extract, a preparation method and a preparation system of the gallium extract, and a gallium purification method and a purification system.

Background Art

In the industrial production process, there is a high demand for gallium. Therefore, the preparation of gallium extract is of great significance.

The existing preparation of gallium extracts usually extracts gallium from gallium-containing ores, which leads to a continuous reduction in gallium resources.

Summary of the invention

The present invention provides a gallium extract, a preparation method and a preparation system of the gallium extract, a gallium purification method and a purification system, aiming to solve the problem that gallium is only extracted from gallium-containing ores in the prior art, resulting in a continuous reduction in gallium resources.

A first aspect of the present invention provides a method for preparing a gallium extract, wherein the gallium extract is derived from furnace ash of a single crystal furnace.

In the present invention, gallium is extracted from the ash of the single crystal furnace instead of extracting gallium from gallium-containing ore, thereby avoiding the reduction of gallium resources, realizing the secondary utilization of the ash of the single crystal furnace, and reducing resource waste.

Optionally, the method comprises:

Removing silicon dioxide from the ash of the single crystal furnace to obtain a preliminary product;

mixing the preliminary product with a base, removing other impurities, and obtaining a gallate solution;

The gallate solution is electrolyzed to obtain a gallium extract.

Optionally, the preliminary product includes: a gallium compound and a compound of other metals except gallium; and the preliminary product is mixed with a base, and other impurities are removed to obtain a gallate solution, comprising:

The preliminary product is mixed with a base to generate a precipitate insoluble in a solution of the base and a gallate soluble in a solution of the base, thereby obtaining a first liquid having a precipitate;

filtering the first liquid to remove compounds of metals other than gallium in the preliminary product to obtain a gallate filtrate;

The step of electrolyzing the gallate solution to obtain a gallium extract comprises:

The gallate filtrate is electrolyzed to obtain a gallium extract.

In the present invention, the silicon dioxide in the ash is first removed, and the content of silicon dioxide in the ash is 75%-90% of the total mass of the ash. Then, the subsequent treatment is only for the substance with a content of 10%-25% in the ash, the mass of the required alkali is small, the cost of treating the waste liquid is also small, and thus, the cost of the recovery method is low. The preliminary product is mixed with alkali, other impurities are removed, and the gallate solution is electrolyzed to obtain a gallium extract. The mass content of gallium in the gallium extract obtained by the method reaches more than 99%.

Optionally, the preliminary product includes: a gallium compound and a compound of other metals except gallium; and the preliminary product is mixed with a base, and other impurities are removed to obtain a gallate solution, comprising:

The preliminary product is mixed with a base to generate a precipitate insoluble in a solution of the base and a gallate soluble in a solution of the base, thereby obtaining a first liquid having a precipitate;

filtering the first liquid to remove compounds of metals other than gallium in the preliminary product to obtain a gallate filtrate;

The step of electrolyzing the gallate solution to obtain a gallium extract comprises:

The gallate filtrate is electrolyzed to obtain a gallium extract.

The preliminary product includes: gallium compounds and compounds of other metals except gallium. The preliminary product is mixed with an alkali, and the compounds of other metals in the preliminary product react with an alkali solution to generate a precipitate insoluble in the alkali solution. The gallium compounds in the preliminary product react with the alkali solution to generate gallate soluble in the alkali solution to obtain a first liquid with a precipitate. The first liquid is filtered to remove the compounds of metals except gallium in the preliminary product to obtain a gallate filtrate. The gallate filtrate is electrolyzed to obtain a gallium extract. The mass content of gallium in the gallium extract obtained by this method reaches more than 99.99%.

Optionally, during the electrolysis process: the pH value of the gallate solution is 8-10; and/or the electrolysis temperature is 25° C.-50° C.; and/or the electrolysis current is 5-20A.

Optionally, removing silicon dioxide from the ash of the single crystal furnace to obtain a preliminary product comprises:

The furnace ash is separated and screened by air flow to remove silicon dioxide in the furnace ash to obtain the preliminary product.

Optionally, the mixing of the preliminary product with a base comprises:

The preliminary product is mixed with an inorganic base; wherein the mass ratio of the preliminary product to the solid inorganic base is: (1:2)-(1:10).

Optionally, removing silicon dioxide from the ash of the single crystal furnace to obtain a preliminary product comprises:

The furnace ash is first heated, and then a halogen gas is introduced into the heated furnace ash to react and generate metal halide gas, which is then collected.

Optionally, the mixing of the preliminary product with a base comprises:

The preliminary product is mixed with an inorganic base; wherein the mass ratio of the preliminary product to the solid inorganic base is: (1:2)-(1:10).

Optionally, removing silicon dioxide from the ash of the single crystal furnace to obtain a preliminary product comprises:

Adding an acid that does not react with silica to the ash to obtain a second liquid with a precipitate;

The second liquid is filtered to remove silicon dioxide in the ash, and the filtrate is collected to obtain the preliminary product.

Optionally, the step of adding an acid that does not react with silicon dioxide to the ash comprises: adding an acid that does not react with silicon dioxide to the ash in an inert gas environment;

and/or, the acid comprises: an inorganic acid;

And/or, the mass ratio of the ash to the acid is: (1:2)-(1:10);

and/or, the acid is added at a rate less than or equal to 5 L/min;

and/or, during the dissolution of the gallium compound and the other metal compound in the acid, the gas pressure is 0.1Mpa-10Mpa;

And/or, filtering the second liquid comprises: using a filter cloth having a pore size greater than 1 um and less than 20 um to filter the second liquid;

and/or, after the acid is added, the ash and the acid are stirred; and the mixing of the preliminary product with the alkali comprises:

The preliminary product is mixed with an inorganic base; wherein the mass ratio of the preliminary product to the solid inorganic base is: (2:1)-(10:1).

Optionally, before using the airflow to separate and screen the ash, the method further comprises:

Using sieves with different mesh sizes to classify the furnace ash according to particle diameters to obtain furnace ash with different particle diameters;

The method of using airflow to separate and screen the ash comprises:

The airflows with different flow rates are used to separate and screen the ash with corresponding particle diameters.

Optionally, the mass content of gallium in the furnace ash is 0.01-5%.

The second aspect of the present invention provides a gallium extract prepared by any of the aforementioned methods for preparing the gallium extract.

A third aspect of the present invention provides a system for preparing a gallium extract using any of the aforementioned methods for preparing a gallium extract, wherein the gallium extract comes from furnace ash of a single crystal furnace.

Optionally, the preparation system comprises: a silicon dioxide removal device, an alkali neutralization device, and an electrolysis device which are sequentially distributed;

The silicon dioxide removal device is used to remove silicon dioxide from the ash of the single crystal furnace to obtain a preliminary product;

The alkali neutralization device is used to mix the preliminary product with alkali to remove other impurities to obtain a gallate solution;

The electrolysis device is used to electrolyze the gallate solution to obtain a gallium extract.

Optionally, the preliminary product includes: a gallium compound and a compound of other metals except gallium;

The alkali neutralization device comprises: an alkali neutralization module and a filtering module;

The alkali neutralization module is used to mix the preliminary product with an alkali to generate a precipitate insoluble in the alkali solution and a gallate soluble in the alkali solution, thereby obtaining a first liquid with a precipitate;

The filtration module is used to filter the first liquid to remove compounds of metals other than gallium in the preliminary product to obtain a gallate filtrate;

The electrolysis device is specifically used to electrolyze the gallate filtrate to obtain a gallium extract. Optionally, the silicon dioxide removal device includes: a separation cylinder; the separation cylinder is used to: use airflow to separate and screen the furnace ash, remove silicon dioxide in the furnace ash, and obtain the preliminary product.

Optionally, the silicon dioxide removal device comprises: a first ash containing container, a halogen gas storage container, and a filter tank, wherein the first ash containing container has an ash feed port, an air inlet, and an air outlet;

The ash enters the first ash containing container from the feed port, the first ash containing container first heats the ash, and then the halogen gas storage container passes halogen gas into the first ash containing container from the air inlet to react and generate metal halide gas, and the metal halide gas enters the filter tank through the air outlet.

Optionally, the silicon dioxide removal device comprises: a second ash accommodating container, a filter element, and an acid liquid storage container, wherein the second ash accommodating container has an acid liquid feed port;

The second ash containing container contains ash, and an acid that does not react with silicon dioxide is added to the ash through the acid liquid feeding port to obtain a second liquid with a precipitate;

The second liquid is filtered through the filter element to remove silicon dioxide in the ash, and the filtered filtrate is collected to obtain the preliminary product.

Optionally, the silicon dioxide removal device further comprises: an inert gas storage container, the second ash containing container further comprising an inert gas inlet, the inert gas storage container being used to introduce inert gas into the second ash containing container through the inert gas inlet to form an inert gas environment; in the inert gas environment, adding an acid that does not react with silicon dioxide into the ash through the acid liquid feed port;

And/or, the second ash containing container further comprises: a spraying structure located at the acid liquid feed port; the spraying structure uniformly sprays the acid into the ash at a speed less than or equal to 5 L/min;

And/or, the silicon dioxide removal device further comprises: a pressure gauge, the pressure gauge being used to measure the air pressure in the second ash containing container;

And/or, the silicon dioxide removal device further comprises: an exhaust gas recovery structure communicated with the second ash containing container;

And/or, the filter element comprises a filter cloth, and the pore size of the filter cloth is greater than 1 um and less than 20 um;

And/or, the second ash containing container further comprises: a stirring structure at the bottom, wherein the stirring structure is used to stir the ash in the second ash containing container and the acid after the acid is added.

A fourth aspect of the present invention provides a method for purifying gallium, comprising: crystallizing the aforementioned gallium extract.

A fifth aspect of the present invention provides a gallium purification system for crystallizing the aforementioned gallium extract.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

FIG1 shows a schematic structural diagram of a single crystal furnace in an embodiment of the present invention;

FIG2 is a flow chart showing the steps of a method for preparing a gallium extract according to an embodiment of the present invention;

FIG3 shows a schematic structural diagram of another single crystal furnace in an embodiment of the present invention;

FIG4 is a schematic diagram showing a partial structure of a silicon dioxide removal device according to an embodiment of the present invention;

FIG5 is a schematic diagram showing a partial structure of another silicon dioxide removal device in an embodiment of the present invention;

FIG. 6 is a schematic diagram showing a partial structure of another silicon dioxide removal device in an embodiment of the present invention.

Description of reference numerals:

1-single crystal furnace, 2-ash deposition container, 3-power cabinet, 4-one-way control valve, 5-silicon dioxide removal device, 51-separation cylinder, 52-screen, 53-first ash containing container, 531-ash feed port, 532-discharge port, 533-heater, 54-halogen gas storage container, 55-filter tank, 56-vacuum component, 57-waste gas treatment component, 58-second ash containing container, 59-filter element, 510-acid storage container, 511-inert gas storage container, 512-pressure gauge, 513-waste gas recovery structure, 514-regulating valve, 515-hydrogen recovery structure, 581-spraying structure, 582-stirring structure.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

The inventors found that gallium-doped single-crystal silicon solar cells have been widely used due to their lower composite defects and photo-induced attenuation. The gallium in existing gallium-doped single-crystal silicon solar cells usually enters the crystalline silicon in the form of doping during the crystal growth process. However, since the segregation coefficient of gallium in silicon is only 0.008, the content of gallium entering the crystalline silicon is relatively small. During the single crystal pulling process, gallium is easily volatilized and eventually taken out in the form of furnace ash. However, in the field of crystal growth technology, the furnace ash of the single crystal furnace is usually treated as solid waste, so that gallium is also treated along with the furnace ash of the single crystal furnace, resulting in great waste.

Therefore, the inventors of the present invention creatively proposed a method for preparing a gallium extract, which is derived from the ash of a single crystal furnace. In the present invention, the gallium extract is derived from the ash of a single crystal furnace, rather than extracting gallium from gallium-containing ores, thereby avoiding the reduction of gallium resources, realizing the secondary utilization of the ash of a single crystal furnace, and reducing resource waste.

The ash of the single crystal furnace here is the volatiles produced during the process of pulling single crystals in the single crystal furnace, and the ash is in the form of powder. Figure 1 shows a schematic diagram of the structure of a single crystal furnace in an embodiment of the present invention. As shown in Figure 1, during the crystal pulling process, the volatiles in the single crystal furnace 1 will enter the ash deposition container 2 along with the exhaust system. After the furnace is shut down, the attachments to the exhaust pipe of the single crystal furnace and the volatiles in the ash deposition container 2 are cleaned to obtain the ash of the single crystal furnace in this application. 3 in Figure 1 is a power cabinet, and the power cabinet 3 provides power for the components in the single crystal furnace 1. The main components of the ash are: silicon dioxide, silicon monoxide, gallium trioxide, and oxides of other metals except gallium. The particle size of the ash is between 5-50um (micrometer).

The method can specifically consider the different physical and/or chemical properties of silicon dioxide, gallium compounds, and compounds of other metals except gallium, and then remove impurities other than gallium in the ash of the single crystal furnace, and extract gallium from the ash of the single crystal furnace, and the specific method is not limited. For example, the ash of the single crystal furnace can be mixed with alkali, silicon dioxide forms silicate colloid in the alkali solution, and the compounds of other metals except gallium will generate precipitates insoluble in the alkali solution in the alkali solution, and the gallium compound will generate gallate that dissolves in the alkali solution in the alkali solution, and the silicate colloid and the above-mentioned precipitates are not dissolved in the gallate, and then the silicate colloid and the above-mentioned precipitate are filtered out to obtain a gallate solution, and the gallate solution is electrolyzed to obtain a gallium extract, and the purity of the gallium extract extracted by this method reaches more than 99%.

FIG2 is a flow chart showing the steps of a method for preparing a gallium extract according to an embodiment of the present invention. Referring to FIG2 , the method comprises the following steps:

Step 101, removing silicon dioxide from the ash of the single crystal furnace to obtain a preliminary product.

Specifically, the inventors found that the mass content of silicon dioxide in the ash of the single crystal furnace is 75%-90%. If the silicon dioxide in the ash is not removed first, but alkali is directly added to the ash, silicon dioxide and silicon dioxide will form silicate colloid in the alkali solution. The silicate colloid will wrap the gallium compound, so that the gallium compound cannot be fully dissolved. At the same time, during the filtration process, the gallate will also be wrapped by the sodium silicate colloid, resulting in part of the gallate cannot be filtered out, so that the gallate filtrate is reduced. Multiple reasons lead to the relatively low quality of the gallium extract obtained in the end. In addition, the alkali needs to react with the silicon dioxide, silicon dioxide, and gallium compounds in the ash, and the compounds of other metals except gallium, so more alkali is needed. The added alkali usually brings in impurities. The more alkali is added, the more impurities are brought in, so that the purity of the gallium extract obtained in the end is relatively low. In addition, more alkali is required, more waste liquid is also more, and the cost of waste liquid treatment is also high.

Therefore, the inventors of the present application creatively removed the silicon dioxide in the ash first to overcome the above problems. The gallium extract obtained by this method has a higher quality, a higher purity, uses less alkali, has a lower cost, and has less waste liquid, and the cost of treating the waste liquid is also lower.

Specifically, the density of the ash of the single crystal furnace is 0.03g/ ^cm3-0.1g / ^cm3 . Optionally, the mass content of gallium in the ash of the single crystal furnace is 0.01%-5%. The method of removing silicon dioxide from the ash of the single crystal furnace is not specifically limited. Specifically, the physical and/or chemical properties of silicon dioxide, gallium compounds and compounds of other metals other than gallium can be considered. In the ash of the single crystal furnace, other metals other than gallium can be: aluminum, iron, zinc, etc. For example, an acid that does not react with silicon dioxide can be used to dissolve the ash, while gallium compounds and compounds of other metals other than gallium are usually dissolved in acid, thereby separating silicon dioxide from other components in the ash.

Since the mass content of silicon dioxide in the ash of the single crystal furnace is 75%-90%, the subsequent treatment is only for 10%-25% of the ash mass, fewer reactants are required, and the cost of treating the waste liquid is also low. Therefore, the recovery method has a low cost.

Step 102, mixing the preliminary product with a base, removing other impurities, and obtaining a gallate solution.

In this step, the gallium compound can generate gallate soluble in the alkali solution in the excess alkali solution, and other impurities other than gallium in the ash of the single crystal furnace without silicon dioxide react with the alkali solution to generate a precipitate insoluble in the alkali solution, thereby removing other impurities. The excess here refers to the fact that almost all gallium compounds in the ash can generate gallate. The embodiments of the present invention do not make specific limitations on this.

Optionally, the preliminary product includes: a gallium compound and a compound of other metals except gallium. Step 102 may include: mixing the preliminary product with an alkali, reacting the compound of other metals in the preliminary product with the alkali solution to generate a precipitate insoluble in the alkali solution, reacting the gallium compound in the preliminary product with the alkali solution to generate a gallate soluble in the alkali solution, and obtaining a first liquid with a precipitate. Filtering the first liquid to remove the compound of metals except gallium in the preliminary product, and obtaining a gallate filtrate.

In this step, the gallium compound can generate gallate soluble in the alkali solution in the excess alkali solution, and the compounds of other metals except gallium in the ash of the single crystal furnace react with the alkali solution to generate a precipitate insoluble in the alkali solution, thereby obtaining a first liquid with a precipitate, and separating the gallium compound and the compounds of other metals except gallium in the ash. The excess here refers to the fact that almost all gallium compounds in the ash can generate gallate. The embodiment of the present invention does not make specific restrictions on this. The main component of the precipitate in the first liquid is the compound of other metals, which reacts with the alkali solution to generate a precipitate insoluble in the alkali solution.

Specifically, the reaction process of gallium compounds in an excess alkali solution is as follows: first, Ga ³⁺ +OH ^- →Ga(OH) ₃ , then, Ga(OH) ₃ +OH ^- →GaO ₂ ^- +2H ₂ O. For example, if the alkali is sodium hydroxide, then Ga(OH) ₃ +NaOH →NaGaO ₂ +2H ₂ O. Gallate ions are usually dissolved in the alkali solution in the form of gallates. Compounds of other metals in the ash except gallium, such as aluminum compounds, iron compounds, zinc compounds, etc., will generate precipitates that are insoluble in the alkali solution, such as iron hydroxide, etc., in the alkali solution, and the reaction is roughly as follows: M ⁿ⁺ +OH ^- →M(OH) _n . Here, M can refer to the element symbol of other metals in the ash except gallium, and n can be the number of positive charges carried by ions of other metals in the ash except gallium, and n is a natural number.

Optionally, an inorganic base may be selected in the above step. The inorganic base will not react with the metal compound to form a complex, will not introduce impurities into the gallate filtrate, and will not affect the purity of the gallium extract obtained subsequently. The purity of the gallium extract obtained thereby is relatively high.

It should be noted that if the preliminary product also contains a small amount of silicon dioxide, the silicon dioxide will form silicate colloid in this step, and the silicate colloid is usually insoluble in an alkaline solution. The silicon dioxide here can be the original silicon dioxide in the furnace ash of the single crystal furnace, or it can be the silicon dioxide formed by converting the silicon dioxide in the furnace ash of the single crystal furnace in step 101. In the embodiments of the invention, there is no specific limitation on this.

The first liquid mainly includes: gallate dissolved in the alkali solution, and precipitate insoluble in the alkali solution generated by reaction with the alkali solution, etc. The precipitate insoluble in the alkali solution is filtered out to separate the gallium in the ash of the single crystal furnace from compounds of other metals except gallium.

If silicate colloid is formed in the above step 102, and silicate colloid is usually insoluble in alkaline solution, it can also be removed by filtering in this step.

Step 103, electrolyzing the gallate solution to obtain a gallium extract.

The gallate solution is electrolyzed under electrolysis conditions corresponding to gallate to obtain a gallium extract, wherein the mass content of gallium in the obtained gallium extract reaches more than 99.99%.

Optionally, in the aforementioned step 102, if a gallate filtrate is obtained after filtering the first liquid, the step 103 may include: electrolyzing the gallate filtrate to obtain a gallium extract. The electrolysis conditions are also the electrolysis conditions corresponding to gallate.

In the present invention, silicon dioxide in the ash is first removed, and the content of silicon dioxide in the ash is 75%-90% of the total mass of the ash. Then, the subsequent treatment is only for the material with a content of 10%-25% in the ash, the mass of the required alkali is small, the cost of treating the waste liquid is also small, and thus, the recovery method has a low cost. The preliminary product is mixed with alkali, and the compounds of other metals in the preliminary product react with the alkali solution to form a precipitate insoluble in the alkali solution, and the gallium compound in the preliminary product reacts with the alkali solution to form a gallate soluble in the alkali solution to obtain a first liquid with a precipitate, and the first liquid is filtered to remove the compounds of metals other than gallium in the preliminary product to obtain a gallate filtrate, and the gallate filtrate is electrolyzed to obtain a gallium extract. The mass content of gallium in the gallium extract obtained by the method reaches more than 99.99%, realizing the secondary utilization of the ash of the single crystal furnace and reducing resource waste.

Optionally, in the above steps, the pH value of the alkaline solution may be 10-14. Within this range, the gallium compound in the ash can be fully dissolved, and the remaining alkali in the waste liquid is relatively small, which is conducive to reducing costs and facilitating the treatment of the waste liquid. For example, the pH value of the alkaline solution may be 10, 11, 12, 12.6, 13, or 14.

Optionally, in the above steps, the alkali may include: sodium hydroxide and/or potassium hydroxide, which are relatively common and easy to obtain.

Optionally, during the electrolysis process: the pH value of the gallate solution or gallate filtrate may be 8-10; and/or the electrolysis temperature may be 25°C-50°C; and/or the electrolysis current may be 5-20A. The above electrolysis conditions are conducive to the rapid extraction of a gallium extract with a higher purity from the gallate solution or gallate filtrate. For example, the pH value of the gallate solution or gallate filtrate may be 8, 8.3, 8.9, 9, 9.5, 9.8, 10. The electrolysis temperature may be 25°C, 26°C, 29°C, 30°C, 32°C, 40°C, 43°C, 45°C, 50°C. The electrolysis current may be 5A, 8A, 10A, 12A, 13A, 15A, 16A, 17A, 18A, 19A, 20A.

Optionally, the aforementioned step 101 may include: using airflow to separate and screen the ash, during which the wind force on the silica particles and silicon dioxide particles in the ash is greater than or equal to their own gravity, while the wind force on other particles in the ash is less than their own gravity, so as to remove the silica and silicon dioxide in the ash and obtain a preliminary product. In the process of removing silica and silicon dioxide from the ash, only wind force is required, no reaction liquid is required, no waste liquid is generated, no waste liquid recovery cost is required, and the gallium recovery cost is low.

Specifically, by utilizing the density difference between gallium trioxide, metal oxides, silicon dioxide, and silicon monoxide, gallium trioxide and other metal oxide particles, silicon dioxide particles, and silicon monoxide particles are obtained to remove silicon dioxide and silicon monoxide from the ash. Wind force opposite to the gravity direction can be given to the ash. The gallium compound in the ash is usually gallium trioxide, and other metals are also usually present in the form of metal oxides. The density of gallium trioxide is 5.9g/ ^cm3 , the density of silicon dioxide is 2.2g/ ^cm3 , and the density of silicon oxide is 2.1g/ ^cm3 . The gravity of silicon dioxide particles and silicon oxide particles are calculated according to the particle range of the furnace ash. Usually, the gravity of metal oxide particles is greater than that of silicon dioxide particles and silicon oxide particles. The wind force is set to be greater than or equal to the gravity of silicon dioxide particles and silicon oxide particles, and less than the gravity of metal oxide particles. Then, the wind force can blow the silicon dioxide particles into a suspended state, or blow the silicon oxide particles into a suspended state, while the metal oxide particles will fall downward under the influence of gravity due to their own greater gravity, thereby removing silicon dioxide and silicon oxide from the furnace ash.

It should be noted that the airflow here may be air flow and/or inert gas flow, which is not specifically limited in the embodiments of the present invention.

Fig. 3 shows a schematic diagram of the structure of another single crystal furnace in an embodiment of the present invention. Referring to Fig. 3, during the crystal pulling process, volatiles in the single crystal furnace 1 are discharged through the exhaust pipe, and a gas one-way control valve 4 is installed in the main exhaust pipe. After the volatiles pass through the gas one-way control valve 4, they flow into the silicon dioxide removal device 5.

Optionally, before using airflow to separate and screen the ash, the method may further include: using screens with different mesh sizes to classify the ash according to particle diameters to obtain ash with different particle diameters. The above-mentioned use of airflow to separate and screen the ash includes: using airflows with different flow rates to separate and screen the ash with corresponding particle diameters. This method can achieve more accurate separation, and the mass proportion of gallium in the obtained preliminary product may be higher, which is conducive to purifying more gallium from the ash.

Specifically, the furnace ash can be passed through sieves of different mesh sizes in turn, and the furnace ash can be classified according to the particle diameter to obtain furnace ash with different particle diameters. According to the different particle diameters, the gravity of silica particles with different particle diameters and the gravity of silicon monoxide particles with different particle diameters are calculated respectively. Generally, the gravity of metal oxide particles with the same particle diameter is greater than the gravity of silica particles with the particle diameter and the gravity of silicon monoxide particles with the particle diameter. If the wind force is set to be greater than or equal to the gravity of silica particles with the particle diameter, the wind force is also greater than the gravity of silicon monoxide particles with the particle diameter. Therefore, the wind force can blow silica particles with the same particle diameter into a suspended state, and can also blow silicon monoxide particles with the particle diameter into a suspended state. Metal oxide particles with the same particle diameter will fall downward under the influence of gravity due to their own gravity being greater than the wind force, and thus the silica and silicon monoxide with the particle diameter in the furnace ash can be removed. By analogy, for the classified ash of each particle diameter, the operation of removing the silicon dioxide and silicon oxide of the particle diameter is performed respectively, so that the silicon dioxide and silicon oxide in the ash are removed.

In the process of determining the wind force corresponding to a certain particle diameter, the Stokes resistance formula can be used: F = 6πμ ₀ Vd. In the formula, F: wind force, μ ₀ : air viscosity coefficient at normal pressure, V: air flow velocity, d: particle diameter. The separation here is usually carried out at room temperature, and the value of μ ₀ can be 1.79×10 ^-5 Pa.s (Pascal seconds). The wind force F here can be set to the gravity of the silica particles greater than or equal to the particle diameter. The gravity of the silica particles of the particle diameter = the mass of the silica particles of the particle diameter × the acceleration of gravity (the value is 9.8N/Kg), the mass of the silica particles of the particle diameter = (3πr ³ /4) × 2.2g/cm ³ , where r = d/2, the d in the calculation of gravity and the d in the Stokes resistance formula are both the particle diameter, then, the air flow velocity V can be calculated by this formula. When the wind force F is greater than or equal to the gravity of the silicon dioxide particles of the particle diameter, the wind force can blow the silicon dioxide particles of the particle diameter to at least a suspended state, and can also blow the silicon monoxide particles of the particle diameter to at least a suspended state, and the gravity of the metal oxide of the particle diameter is often greater than the gravity of the silicon dioxide particles of the particle diameter, and the gravity of the metal oxide of the particle diameter is greater than the wind force F, and then, the metal oxide of the particle diameter still falls in the direction of gravity under the action of the wind force, and then the silicon dioxide and silicon monoxide in the ash of the particle diameter can be removed. By analogy, all silicon dioxide and silicon monoxide in the ash of the particle diameter can be removed.

Optionally, using airflows with different flow rates to separate and screen furnace ash of corresponding particle diameters includes: using an air flow with a flow rate greater than or equal to 1.34 cm/s to separate and screen furnace ash with a particle diameter of 20 um. Specifically, the density of silicon dioxide is 2.2 g/cm ³ , the density of silicon dioxide is 2.1 g/cm ³ , and the mass of silicon dioxide particles with a particle diameter of 20 um is 9.22×10 ^-9 g. The F in the formula F＝6πμ ₀ Vd is determined as the gravity corresponding to the mass greater than or equal to 9.22×10 ^-9 g, and μ ₀ can be taken as: 1.79×10 ^-5 Pa.s, where d＝20 um. It is calculated that the air flow rate V is greater than or equal to 1.34 cm/s, and gallium trioxide particles can be collected below the separation cylinder 51.

Optionally, if airflow is used to separate and screen the ash to remove silicon dioxide in the ash. Then, in the above step 102, if an inorganic base is selected, the mass ratio of the preliminary product to the solid inorganic base can be: (1:2)-(1:10). The mass ratio of the preliminary product to the solid inorganic base within this range can fully dissolve the gallium compounds in the ash, and the remaining inorganic base in the waste liquid is relatively small, which is conducive to reducing costs and facilitating the treatment of the waste liquid. For example, the mass ratio of the preliminary product to the solid inorganic base can be: 1:2, 1:3, 1:4, 1:4.2, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10.

Optionally, the above step 101 may include: first heating the ash, and then introducing a halogen gas into the heated ash, wherein the gallium compound and other metal compounds in the heated ash react with the halogen gas in the halogen gas environment to generate metal halide gas, and the silicon dioxide in the heated ash exists as a solid, the metal halide gas is collected, and the silicon dioxide in the ash of the single crystal furnace is removed to obtain a preliminary product. The specific type of the halogen gas is not limited here, for example, the halogen gas may be a halogen gas and/or a Freon gas, etc.

Specifically, the boiling points of metal oxides and silicon dioxide in the ash are very high. For example, the boiling point of gallium trioxide is usually greater than 2000°C. The metal oxides with high boiling points in the ash heated to 700°C-1100°C are converted into metal halides with lower boiling points through halogen gases. The metal halides are already gases in the range of 700°C-1100°C. At the same time, silicon dioxide does not react with halogen gases and still maintains a very high boiling point, being solid in the range of 700°C-1100°C. The difference in boiling points between silicon dioxide and metal halides is used to separate silicon dioxide from the ash. The method of removing silicon dioxide from the ash has few process steps and high efficiency.

Optionally, if the ash is heated first, and then a halogen gas is introduced into the heated ash, the silicon dioxide in the ash of the single crystal furnace is removed in a halogen environment to obtain a preliminary product. Then, in the above step 102, if an inorganic base is selected, the mass ratio of the preliminary product to the solid inorganic base can be: (1:2)-(1:10). The mass ratio of the preliminary product to the solid inorganic base within this range can fully dissolve the gallium compounds in the ash, and the remaining inorganic base in the waste liquid is relatively small, which is conducive to reducing costs and facilitating the treatment of waste liquid. For example, the mass ratio of the preliminary product to the solid inorganic base can be: 1:2, 1:3, 1:4, 1:4.2, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10.

Optionally, the above step 101 may include: adding an acid that does not react with silica, gallium compounds and other metal compounds to the ash, dissolving them in the acid, while the silica in the ash does not dissolve in the acid, to obtain a second liquid with a precipitate; filtering the second liquid to remove the silica in the ash, collecting the filtered filtrate, and obtaining a preliminary product. By taking advantage of the fact that silica is insoluble in the acid, while gallium compounds and other metal compounds can dissolve in the acid that does not react with silica, the silica in the ash can be removed by acid leaching in one step, the process steps are simple, and the acid used to remove the silica in the ash only needs to dissolve the part except for the silica, that is, the acid used here is only for the part with a mass content of 25%-10% of the ash, and the amount of acid used is small, which can reduce costs, and the waste liquid is relatively small, which can also reduce the cost of waste liquid treatment. For example, the acid here can be sulfuric acid, hydrochloric acid, nitric acid, etc. There is no limitation on the specific type of acid that does not react with silica.

Gallium trioxide in the ash reacts with the acid that does not react with silicon dioxide as follows: Ga ₂ O ₃ +6H ⁺ →2Ga ³⁺ +3H ₂ O. Other metal oxides in the ash except gallium react with the acid as follows: M _x O+aH ⁺ →M _x ^a+ +H ₂ O, where M can refer to the element symbol of other metals in the ash except gallium, and x is the number of atoms of metal M in the chemical formula of the oxide of other metals in the ash except gallium, and x is a natural number. a is the number of positive charges carried by the M _x ^a+ ion, and a is a natural number. Silicon dioxide in the ash reacts with the acid as follows: SiO+4H ⁺ →Si ⁴⁺ +H ₂ O+H ₂ . The acid here converts silicon dioxide into tetravalent silicon ions, which form silicate colloids in the alkali in step 102, and silicate colloids are usually insoluble in the alkali solution. Therefore, silicon dioxide in the ash can also be removed in the above step 102. The main component of the precipitate in the second liquid having the precipitate is silicon dioxide.

Due to the presence of silicon oxide, the ash reacts with the acid to continuously generate hydrogen. If the above reaction is carried out in a closed container, the pressure of the closed container will continue to rise. Optionally, the optimal dissolution pressure of gallium trioxide is 0.1Mpa-10Mpa. Therefore, during the process of dissolving gallium compounds and other metal compounds in the acid, the gas pressure is 0.1Mpa-10Mpa, which is conducive to the dissolution of gallium trioxide in the acid.

Optionally, adding an acid that does not react with silica to the ash includes: adding an acid that does not react with silica to the ash in an inert gas environment, thereby exhausting the air in the reaction environment, etc., to reduce the oxygen in the reaction environment and prevent oxygen from participating in the reaction. The inert gas may be nitrogen, argon, etc.

And/or, optionally, the concentration of the acid can be: 0.1mol/L-3mol/L. The acid concentration within this range is not only conducive to the more thorough dissolution of gallium trioxide and other metal oxides in the ash, but also the acid liquid is basically used up, which is not only conducive to reducing costs, but also can reduce the pressure of waste liquid treatment. For example, the acid concentration can be: 0.1mol/L, 0.4mol/L, 0.5mol/L, 0.8mol/L, 1mol/L, 1.2mol/L, 2mol/L, 2.4mol/L, 3mol/L.

And/or, optionally, the mass ratio of ash to acid can be: (1:2)-(1:10). The mass ratio of ash to acid within this range is not only conducive to the more thorough dissolution of gallium trioxide and other metal oxides in the ash, but also the acid is basically used up, which is not only conducive to reducing costs, but also can reduce the pressure of waste liquid treatment. For example, the mass ratio of ash to acid can be: 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10.

And/or, optionally, the speed of adding the acid is less than or equal to 5 L/min, so that the reaction of generating hydrogen is not violent, the safety performance is good, and the acid liquid and the ash are in full contact, and the amount of acid used can be appropriately reduced. The uniformity of adding the acid can also be regulated so that the acid is evenly added to the ash, which can also make the reaction of generating hydrogen not violent, the safety performance is good, and the acid liquid and the ash are in full contact, and the amount of acid used can be appropriately reduced.

And/or, optionally, filtering the second liquid includes: using a filter cloth with a pore size greater than 1 um and less than 20 um to filter the second liquid, wherein gallium and other metal compounds in the ash are dissolved in acid, wherein the pore size of the filter cloth is greater than 1 um and less than 20 um, and most of the silicon dioxide particles can be filtered out, so that the gallium content in the obtained preliminary product is higher.

Optionally, the acid may be an inorganic acid. The inorganic acid may be hydrochloric acid, sulfuric acid, nitric acid, etc., and the type of the inorganic acid is not specifically limited. The inorganic acid will not introduce impurities into the preliminary product, and will not affect the purity of the gallium extract obtained subsequently, so that the purity of the gallium extract obtained subsequently is higher.

Optionally, after the acid is added, the ash and the acid may be stirred so that the ash and the acid are in more complete contact, thereby increasing the reaction rate.

The present invention also provides a gallium extract, which is prepared by any of the aforementioned methods for preparing gallium extracts. The gallium extract has the same or similar beneficial effects as any of the aforementioned methods for preparing gallium extracts, and will not be described in detail herein to avoid repetition.

The present invention also provides a preparation system for preparing gallium extract by using any of the above-mentioned preparation methods for gallium extract, wherein the gallium extract comes from the ash of a single crystal furnace. The preparation system has the same or similar beneficial effects as the above-mentioned preparation method for gallium extract.

Optionally, the preparation system includes: a silicon dioxide removal device, an alkali neutralization device, and an electrolysis device, which are sequentially arranged. The silicon dioxide removal device is used to remove silicon dioxide from the furnace ash of the single crystal furnace to obtain a preliminary product. The alkali neutralization device is used to mix the preliminary product with an alkali to remove other impurities to obtain a gallate solution. The electrolysis device is used to electrolyze the gallate solution to obtain a gallium extract.

Optionally, the preliminary product includes: gallium compounds and compounds of other metals except gallium; the aforementioned alkali neutralization device includes: an alkali neutralization module and a filtration module. The alkali neutralization module is used to mix the preliminary product with an alkali, and the compounds of other metals in the preliminary product react with the alkali solution to generate a precipitate insoluble in the alkali solution, and the gallium compounds in the preliminary product react with the alkali solution to generate gallate soluble in the alkali solution, thereby obtaining a first liquid with a precipitate. The filtration module is used to filter the first liquid to remove the compounds of metals except gallium in the preliminary product to obtain a gallate filtrate; the electrolysis device is specifically used to electrolyze the gallate filtrate to obtain a gallium extract.

Optionally, FIG4 shows a schematic diagram of the partial structure of a silicon dioxide removal device in an embodiment of the present invention. Referring to FIG3 and FIG4, the silicon dioxide removal device 5 has a separation cylinder 51, and the separation cylinder 51 is used to: use airflow to separate and screen the ash. During the separation and screening process, the wind force received by the silicon dioxide particles and silicon monoxide particles in the ash is greater than or equal to their own gravity, while the wind force received by other particles in the ash is less than their own gravity, so as to remove the silicon dioxide and silicon monoxide in the ash and obtain a preliminary product. The silicon dioxide removal device shown in FIG4 relies only on wind power, does not require reaction liquid, etc., does not generate waste liquid, has no waste liquid recovery cost, and has low recovery cost.

As shown in FIG4 , the silicon dioxide removal device 5 may also include: a screen 52, which passes the furnace ash through the screens 52 of different mesh sizes in sequence, and classifies the furnace ash according to the particle diameter to obtain furnace ash with different particle diameters. According to the different particle diameters, the gravity of the silicon dioxide particles with different particle diameters and the gravity of the silicon monoxide particles with different particle diameters are calculated respectively. The wind force is set to be greater than or equal to the gravity of the silicon dioxide particles with a certain particle diameter, and the gravity of the metal oxide particles in the furnace ash with a particle diameter smaller than the particle diameter, then the wind force is also greater than the gravity of the silicon monoxide particles with the particle diameter, and then, the wind force can blow the silicon dioxide particles with the same particle diameter into a suspended state, and can also blow the silicon monoxide particles into a suspended state, while the metal oxide particles with the same particle diameter will fall downward under the influence of gravity due to their own greater gravity, and then the silicon dioxide and silicon monoxide with the particle diameter in the furnace ash can be removed. By analogy, for the classified ash of each particle diameter, the operation of removing the silicon dioxide and silicon oxide of the particle diameter is performed respectively, so that the silicon dioxide and silicon oxide in the ash are removed.

FIG5 shows a schematic diagram of the partial structure of another silicon dioxide removal device in an embodiment of the present invention. Referring to FIG5 , the silicon dioxide removal device 5 includes: a first ash accommodating container 53, a halogen gas storage container 54, and a filter tank 55. The first ash accommodating container 53 has an ash feed port 531, an air inlet, and an air outlet. The ash enters the first ash accommodating container 53 from the feed port 531. A heater 531 is provided on the outside of the first ash accommodating container 53. The ash is heated by the heater 533. The heating temperature is not specifically limited. For example, the ash can be heated to 700°C-1100°C. After the ash is heated, the halogen gas storage container 54 introduces halogen gas into the first ash accommodating container 53 from the air inlet. The gallium compounds and other metal compounds in the heated ash react with the halogen gas to generate metal halide gas. The silicon dioxide in the heated ash exists as a solid. The metal halide gas generated by the reaction enters the filter tank 55 through the air outlet. The substance in the filter tank 55 is the above-mentioned preliminary product, and its main component is metal halide. Solid substances such as silicon dioxide in the ash that do not react with halogen gas are discharged from the first ash container 53 from the discharge port 532 of the first ash container 53. The method of removing silicon dioxide from the ash by the silicon dioxide removal device has few process steps and high efficiency. The first ash container 53 here is not specifically limited. For example, the first ash container 53 here can be a rotary furnace.

The silicon dioxide removal device 5 may further include an exhaust component 56 and an exhaust gas treatment component 57 located after the filter tank 55 to reduce the exhaust gas from polluting the environment, etc. The exhaust component 56 provides power for the exhaust gas to move toward the exhaust gas treatment component 57, where the exhaust gas is mainly halogen gas.

Optionally, during the process of heating the ash to 700°C-1100°C, the total heating time is 20 minutes-60 minutes. Within this range, the thermal stress on the first ash containing container 53 is relatively small, the life of the first ash containing container 53 can be improved, and the heating time will not be too long.

FIG6 shows a partial structural schematic diagram of another silicon dioxide removal device in an embodiment of the present invention. Referring to FIG6 , the silicon dioxide removal device 5 may include: a second ash accommodating container 58, a filter element 59, and an acid liquid storage container 510, wherein the second ash accommodating container 58 has an acid liquid feed port. The second ash accommodating container 58 contains ash, and an acid that does not react with silicon dioxide, gallium compounds and other metal compounds are added to the ash from the acid liquid storage container 510 through the acid liquid feed port, and dissolved in the acid, while the silicon dioxide in the ash does not dissolve in the acid, thereby obtaining a second liquid with precipitation. The second liquid is filtered through the filter element 59 to remove the silicon dioxide in the ash, and the filtered filtrate is collected to obtain a preliminary product. The silicon dioxide removal device utilizes the fact that silicon dioxide is insoluble in acids that do not react with silicon dioxide, while gallium compounds and other metal compounds can be dissolved in acids that do not react with silicon dioxide. The silicon dioxide in the ash can be removed by acid leaching in one step. The process steps are simple, and the acid used to remove the silicon dioxide in the ash only needs to dissolve the part except the silicon dioxide. That is to say, the acid used here is only for the part with a mass content of 25%-10% of the ash. The amount of acid used is small, which can reduce costs. At the same time, the waste liquid is relatively small, which can also reduce the cost of waste liquid treatment.

There is no specific limitation on the second ash containing container 58. For example, the second ash containing container 58 may be a reactor.

Optionally, as shown in Figure 6, the second ash holding container 58 may also include a spray structure 581 located at the acid liquid feed port, through which the acid is evenly and slowly sprayed into the ash at a speed less than or equal to 5L/min, so that the reaction to generate hydrogen is not violent, the safety performance is good, and the acid liquid and the ash can be fully contacted, and the amount of acid used can be appropriately reduced.

Optionally, as shown in FIG. 6 , the silicon dioxide removal device may further include: an inert gas storage container 511, the second ash container 58 also has an inert gas inlet, the inert gas storage container 511 is used to pass inert gas into the second ash container 58 through the inert gas inlet to form an inert gas environment, in which an acid that does not react with silicon dioxide is added to the ash from the acid storage container 510 through the acid liquid feed port, and then the air in the second ash container 58 is discharged, thereby reducing the oxygen in the second ash container 58 and preventing oxygen from participating in the reaction. The inert gas may be: nitrogen, argon, etc.

And/or, optionally, as shown in Fig. 6, the silicon dioxide removal device may further include: a pressure gauge 512, which is used to measure the air pressure in the second ash containing container 58. The optimal dissolution pressure of gallium trioxide is 0.1Mpa-10Mpa, so when gallium compounds and other metal compounds are dissolved in acid, the air pressure of the second ash containing container 58 is 0.1Mpa-10Mpa.

And/or, optionally, as shown in FIG. 6 , the silicon dioxide removal device may further include: a waste gas recovery structure 513, which can collect inert gas, etc. At the same time, the silicon dioxide in the ash reacts with the acid in the following manner: SiO+4H ⁺ →Si ⁴⁺ +H ₂ O+H ₂ . The acid here converts silicon dioxide into tetravalent silicon ions, which form silicate colloids in the alkali in step 102, and the silicate colloids are generally insoluble in the alkali solution, so silicon dioxide in the ash can also be removed. With the generation of hydrogen, etc., the gas pressure in the second ash container 58 may be greater than 10Mpa, and the gas in the second ash container 58 can be collected into the waste gas recovery structure 513 through a pipeline, so that the gas pressure in the second ash container 58 is always maintained at 0.1Mpa-10Mpa, so as to facilitate the dissolution of gallium trioxide in the acid. The rate of hydrogen generation can be controlled by slowly adding the acid to prevent the pressure in the second ash container 58 from increasing too fast. For example, if the rate of acid addition is less than or equal to 5 L/min, the reaction of generating hydrogen can be less intense, the safety performance is good, and the acid solution and ash can be fully contacted, so the amount of acid can be appropriately reduced.

Optionally, as shown in FIG. 6 , the silicon dioxide removal device may further include: a hydrogen recovery structure 515 located at the top of the second ash containing container 58 for recovering hydrogen generated by the reaction of silicon dioxide and acid; the recovered hydrogen may be used as fuel, etc., thereby reducing waste of resources.

Optionally, the filter element 59 may include a filter cloth having a pore size greater than 1 um and less than 20 um. Gallium and other metal compounds in the ash are dissolved in the acid. Here, the pore size of the filter cloth is greater than 1 um and less than 20 um, and most of the silica particles can be filtered out, so that the gallium content in the obtained preliminary product is higher.

Optionally, as shown in Figure 6, the second ash containing container 58 also includes a stirring structure 582 located at the bottom. The stirring structure 582 is used to stir the ash and acid in the second ash containing container 58 after the acid is added, so that the ash and the acid are in more sufficient contact, which can increase the reaction rate.

Optionally, as shown in FIG. 6 , the silicon dioxide removal device 5 may further include: a regulating valve 514 located between the second ash containing container 58 and the filter element 59 , which controls the second liquid in the second ash containing container 58 to enter the filter element 59 after the reaction is completed.

The present invention also provides a method for purifying gallium, which may include: crystallizing the gallium extract prepared by the aforementioned method for preparing the gallium extract to obtain gallium with higher purity. The number of crystallizations is not specifically limited. For example, crystallization may be performed once or multiple times.

The present invention also provides a gallium purification system for crystallizing the gallium extract prepared by the above-mentioned gallium extract preparation method to obtain gallium with higher purity. The number of crystallizations is not specifically limited. For example, crystallization can be performed once or multiple times.

It should be noted that the relevant parts of the aforementioned method for preparing gallium extract, gallium extract, system for preparing gallium extract, gallium purification method and gallium purification system can be referenced to each other and can achieve the same or similar effects.

The present invention is further explained below in conjunction with specific embodiments.

Example 1

20kg of furnace ash was separated and screened by air flow to remove silicon dioxide and silicon dioxide, and 5.1kg of preliminary product was obtained. 10.67kg of solid sodium hydroxide was dissolved in 25kg of water to obtain a sodium hydroxide solution with a concentration of 10.6mol/L. 5.1kg of preliminary product was mixed with the above sodium hydroxide solution, and the gallium compound in the preliminary product reacted with the sodium hydroxide solution to form sodium gallate soluble in the sodium hydroxide solution. The compounds of other metals in the preliminary product, except gallium, reacted with the sodium hydroxide solution to form a precipitate insoluble in the sodium hydroxide solution, and a first liquid with a precipitate was obtained. The first liquid was filtered to obtain a sodium gallate solution. Then, the sodium gallate solution was electrolyzed. During the electrolysis process, the pH value of the sodium gallate solution was 9.3, the electrolysis temperature was 35°C, and the electrolysis current was 11A. 0.15kg of gallium extract with a purity of 99.99% was obtained by electrolysis.

Example 2

In a chlorine environment, 20 kg of furnace ash is heated to 1000 ° C, and the total heating time is 40 minutes. The gallium compounds and other metal compounds in the heated furnace ash react with chlorine to generate metal chloride gas, while the silicon dioxide in the heated furnace ash exists as a solid. The metal chloride gas is collected, and the silicon dioxide in the furnace ash of the single crystal furnace is removed, and the initial product obtained is 10.34 kg. 12.2 kg of sodium hydroxide is dissolved in 40 kg of water to obtain a sodium hydroxide solution with a concentration of 7.62 mol/L. 10.34 kg of the initial product is mixed with the above sodium hydroxide solution, and the gallium compounds in the initial product react with the sodium hydroxide solution to generate sodium gallate soluble in the sodium hydroxide solution. The compounds of other metals in the initial product except gallium react with the sodium hydroxide solution to generate a precipitate insoluble in the sodium hydroxide solution, and the first liquid with precipitate is obtained. The first liquid is filtered to obtain a sodium gallate solution. Then, the sodium gallate solution was electrolyzed, during which the pH value of the sodium gallate solution was 9.3, the electrolysis temperature was 35° C., and the electrolysis current was 11 A. 0.146 kg of gallium extract with a purity of 99.99% was obtained by electrolysis.

Example 3

Dissolve 16.28L of 18.4mol/L concentrated sulfuric acid in 87kg of water to obtain a sulfuric acid solution with a concentration of 3mol/L. In an inert gas environment, add the above sulfuric acid solution to 20kg of furnace ash at a rate of 3L/min. Gallium compounds and other metal compounds in the furnace ash are dissolved in sulfuric acid, while silicon dioxide in the furnace ash is insoluble in sulfuric acid, and a second liquid with a precipitate is obtained. The second liquid is filtered using a filter cloth with a pore size of 10um to remove silicon dioxide in the furnace ash of the single crystal furnace. The volume of the obtained preliminary product is about 104L. 12.7kg of sodium hydroxide is slowly added to the above preliminary product. The gallium compounds in the preliminary product react with sodium hydroxide to form sodium gallate soluble in sodium hydroxide solution, and the compounds of other metals in the preliminary product except gallium react with sodium hydroxide solution to form a precipitate insoluble in sodium hydroxide solution, and a first liquid with a precipitate is obtained. Filter the first liquid to obtain a sodium gallate solution. Then, the sodium gallate solution was electrolyzed, during which the pH value of the sodium gallate solution was 9, the electrolysis temperature was 35° C., and the electrolysis current was 11 A. 0.24 kg of gallium extract with a purity of 99.99% was obtained by electrolysis.

Example 4

Dissolve 30 kg of sodium hydroxide in 110 kg of water to obtain a sodium hydroxide solution. Add 20 kg of furnace ash to the above sodium hydroxide solution, and the silicon dioxide and silicon oxide in the furnace ash react with the sodium hydroxide to form sodium silicate colloid. The compounds of other metals in the furnace ash, except gallium, react with the sodium hydroxide solution to form a precipitate insoluble in the sodium hydroxide solution, and obtain a third liquid with a precipitate. The precipitate in the third liquid mainly includes: sodium silicate colloid, and the compounds of other metals in the furnace ash, except gallium, react with the alkaline solution to form a precipitate insoluble in the alkaline solution. Filter the third liquid to obtain a sodium gallate solution. Then, the sodium gallate solution is electrolyzed. During the electrolysis process, the pH value of the sodium gallate solution is 9, the electrolysis temperature is 35°C, and the electrolysis current is 11A. Electrolysis obtains 0.08 kg of gallium extract with a purity of 99.91%.

The ash used in the above-mentioned Example 1, Example 2, Example 3 and Example 4 is the ash from the same batch in the same ash deposition container 2. The following table is a parameter comparison table of Example 1, Example 2, Example 3 and Example 4.

Parameter comparison table of embodiment 1, embodiment 2, embodiment 3 and embodiment 4

Through the above embodiments and the above table, it can be concluded that the gallium extract obtained by the method of the embodiment of the present invention is of higher quality and higher purity, which realizes the recycling of gallium, realizes the secondary utilization of the furnace ash of the single crystal furnace, and reduces the waste of resources. At the same time, for the same quality of furnace ash, the gallium extract obtained by purification in Example 1, Example 2, and Example 3 is of higher quality and higher purity than that in Example 4. The specific reason is that, first, there is less sodium silicate in the first liquid, so the sodium silicate wraps less gallium compounds, so that the gallium compounds can be fully dissolved. At the same time, during the filtration process, the sodium silicate colloid wraps less sodium gallate, so that the obtained sodium gallate filtrate is more. At the same time, in the embodiment of the present invention, the alkali that needs to be added is only for substances other than silicon dioxide, the mass of the added alkali is less, the impurities introduced by the alkali are less, and the purity of the gallium extract obtained is also higher. Moreover, for the same quality of furnace ash, the alkali that needs to be added in Example 1, Example 2, and Example 3 is only for substances other than silicon dioxide, the mass of the added alkali is less, and therefore the waste liquid is less.

It should be noted that, for the method embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the embodiments of the present application are not limited by the described order of actions, because according to the embodiments of the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present application.

It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM/RAM, a magnetic disk, or an optical disk), and includes a number of instructions for enabling a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims (19)

1. A method for preparing a gallium extract, characterized in that the gallium extract comes from the ash of a single crystal furnace; the ash comprises silicon dioxide, silicon monoxide, gallium trioxide, and oxides of other metals except gallium; The method comprises: Removing silicon dioxide from the ash of the single crystal furnace to obtain a preliminary product; A gallium extract is obtained from the preliminary product. 2. The method for preparing the gallium extract according to claim 1, characterized in that the gallium extract is obtained from the preliminary product, comprising: mixing the preliminary product with a base, removing other impurities, and obtaining a gallate solution; The gallate solution is electrolyzed to obtain a gallium extract. 3. The method for preparing a gallium extract according to claim 2, characterized in that the preliminary product comprises: a gallium compound and a compound of other metals except gallium; the preliminary product is mixed with an alkali to remove other impurities to obtain a gallate solution, comprising: The preliminary product is mixed with a base to generate a precipitate insoluble in a solution of the base and a gallate soluble in a solution of the base, thereby obtaining a first liquid having a precipitate; filtering the first liquid to remove compounds of metals other than gallium in the preliminary product to obtain a gallate filtrate; The step of electrolyzing the gallate solution to obtain a gallium extract comprises: The gallate filtrate is electrolyzed to obtain a gallium extract. 4. The method for preparing a gallium extract according to claim 2 or 3, characterized in that during the electrolysis process: the pH value of the gallate solution is 8-10; and/or the electrolysis temperature is 25°C-50°C; and/or the electrolysis current is 5-20A. 5. The method for preparing gallium extract according to claim 2, characterized in that the removing of silicon dioxide from the ash of the single crystal furnace to obtain the preliminary product comprises: The furnace ash is separated and screened by air flow to remove silicon dioxide in the furnace ash to obtain the preliminary product. 6. The method for preparing the gallium extract according to claim 5, characterized in that the mixing of the preliminary product with a base comprises: The preliminary product is mixed with an inorganic base; wherein the mass ratio of the preliminary product to the solid inorganic base is: (1:2)-(1:10). 7. The method for preparing gallium extract according to claim 2, characterized in that the removing of silicon dioxide from the ash of the single crystal furnace to obtain the preliminary product comprises: The furnace ash is first heated, and then a halogen gas is introduced into the heated furnace ash to react and generate metal halide gas, which is then collected. 8. The method for preparing a gallium extract according to claim 7, characterized in that the mixing of the preliminary product with a base comprises: The preliminary product is mixed with an inorganic base; wherein the mass ratio of the preliminary product to the solid inorganic base is: (1:2)-(1:10). 9. The method for preparing gallium extract according to claim 2, characterized in that the removing of silicon dioxide from the ash of the single crystal furnace to obtain the preliminary product comprises: Adding an acid that does not react with silica to the ash to obtain a second liquid with a precipitate; The second liquid is filtered to remove silicon dioxide in the ash, and the filtrate is collected to obtain the preliminary product. 10. The method for preparing gallium extract according to claim 9, characterized in that the step of adding an acid that does not react with silicon dioxide to the furnace ash comprises: adding an acid that does not react with silicon dioxide to the furnace ash in an inert gas environment; and/or, the acid comprises: an inorganic acid; And/or, the mass ratio of the ash to the acid is: (1:2)-(1:10); and/or, the acid is added at a rate less than or equal to 5 L/min; and/or, during the dissolution of the gallium compound and the other metal compound in the acid, the gas pressure is 0.1Mpa-10Mpa; And/or, filtering the second liquid comprises: using a filter cloth having a pore size greater than 1 um and less than 20 um to filter the second liquid; and/or, after the acid is added, stirring the furnace ash and the acid; The step of mixing the preliminary product with a base comprises: The preliminary product is mixed with an inorganic base; wherein the mass ratio of the preliminary product to the solid inorganic base is: (2:1)-(10:1). 11. The method for preparing gallium extract according to claim 5, characterized in that before separating and screening the ash by airflow, the method further comprises: Using sieves with different mesh sizes to classify the furnace ash according to particle diameters to obtain furnace ash with different particle diameters; The method of using airflow to separate and screen the ash comprises: The airflows with different flow rates are used to separate and screen the ash with corresponding particle diameters. 12. The method for preparing a gallium extract according to any one of claims 1 to 3, characterized in that the mass content of gallium in the ash is 0.01-5%. 13. A system for preparing gallium extract using the method for preparing gallium extract according to any one of claims 1 to 12, characterized in that the gallium extract comes from furnace ash of a single crystal furnace. 14. The preparation system according to claim 13, characterized in that it comprises: a silicon dioxide removal device, an alkali neutralization device, and an electrolysis device which are sequentially distributed; The silicon dioxide removal device is used to remove silicon dioxide from the ash of the single crystal furnace to obtain a preliminary product; The alkali neutralization device is used to mix the preliminary product with alkali to remove other impurities to obtain a gallate solution; The electrolysis device is used to electrolyze the gallate solution to obtain a gallium extract. 15. The preparation system according to claim 14, characterized in that the preliminary product comprises: a gallium compound and a compound of other metals except gallium; The alkali neutralization device comprises: an alkali neutralization module and a filtering module; The alkali neutralization module is used to mix the preliminary product with an alkali to generate a precipitate insoluble in the alkali solution and a gallate soluble in the alkali solution, thereby obtaining a first liquid with a precipitate; The filtration module is used to filter the first liquid to remove compounds of metals other than gallium in the preliminary product to obtain a gallate filtrate; The electrolysis device is specifically used to electrolyze the gallate filtrate to obtain a gallium extract. 16. The preparation system according to claim 14 or 15, characterized in that the silicon dioxide removal device comprises: a separation cylinder; the separation cylinder is used to: use airflow to separate and screen the ash, remove the silicon dioxide in the ash, and obtain the preliminary product. 17. The preparation system according to claim 14 or 15, characterized in that the silicon dioxide removal device comprises: a first ash containing container, a halogen gas storage container, and a filter tank, wherein the first ash containing container has an ash feed port, an air inlet, and an air outlet; The ash enters the first ash containing container from the feed port, the first ash containing container first heats the ash, and then the halogen gas storage container passes halogen gas into the first ash containing container from the air inlet to react and generate metal halide gas, and the metal halide gas enters the filter tank through the air outlet. 18. The preparation system according to claim 14 or 15, characterized in that the silicon dioxide removal device comprises: a second ash accommodating container, a filter element, and an acid liquid storage container, wherein the second ash accommodating container has an acid liquid feed port; The second ash containing container contains ash, and an acid that does not react with silicon dioxide is added to the ash through the acid liquid feeding port to obtain a second liquid with a precipitate; The second liquid is filtered through the filter element to remove silicon dioxide in the ash, and the filtered filtrate is collected to obtain the preliminary product. 19. The preparation system according to claim 18, characterized in that the silicon dioxide removal device further comprises: an inert gas storage container, the second ash containing container further comprising an inert gas inlet, the inert gas storage container is used to pass inert gas into the second ash containing container through the inert gas inlet to form an inert gas environment; in the inert gas environment, an acid that does not react with silicon dioxide is added to the ash through the acid liquid feed port; And/or, the second ash containing container further comprises: a spraying structure located at the acid liquid feed port; the spraying structure uniformly sprays the acid into the ash at a speed less than or equal to 5 L/min; And/or, the silicon dioxide removal device further comprises: a pressure gauge, the pressure gauge being used to measure the air pressure in the second ash containing container; And/or, the silicon dioxide removal device further comprises: an exhaust gas recovery structure communicated with the second ash containing container; And/or, the filter element comprises a filter cloth, and the pore size of the filter cloth is greater than 1 um and less than 20 um; And/or, the second ash containing container further comprises: a stirring structure at the bottom, wherein the stirring structure is used to stir the ash in the second ash containing container and the acid after the acid is added.