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Method for extraction of gallium from fly ash. RU patent 2507282.

IPC classes for russian patent Method for extraction of gallium from fly ash. RU patent 2507282. (RU 2507282):

C22B7/02 - Working-up flue dust

C22B58/00 - Obtaining gallium or indium

C22B3/24 - by adsorption on solid substances, e.g. by extraction with solid resins

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Method for extraction of gallium from fly ash / 2506332
Invention refers to a method for extraction of gallium from fly ash. The method involves crushing of fly ash and extraction of Fe by magnetic separation. Then, it is diluted with hydrochloric acid so that hydrochloric-acid leaching product is obtained, gallium is adsorbed by means of macroporous cationic resin, and further elution is performed so that a gallium-containing eluent is obtained. Then, a masking agent is added for masking of a trivalent iron ion so that a gallium-containing eluent is obtained. After masking is completed, gallium is adsorbed in the eluent by means of macroporous cationic resin with further elution and production of the secondary eluent, solution of sodium hydroxide is added to the secondary eluent for carrying out the reaction, and a deposit is filtered and removed after the reaction is completed. Then, the filtrate is concentrated and an electrolysis is performed so that metallic gallium is obtained.

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FIELD: metallurgy.

SUBSTANCE: method involves fly ash crushing, removal of Fe by magnetic separation; then, its dilution in a hydrochloric acid so that a hydrochloric leaching product is obtained. Then, adsorption of gallium contained in the hydrochloric leaching product is performed by means of macroporous cationic resin with further production of eluent containing gallium; addition of sodium hydroxide solution to the eluent for carrying out the reaction and obtaining a sodium metaaluminate solution containing gallium. Then, CO₂ is added to the sodium metaaluminate solution containing gallium for carbonisation with further separation of gallium from aluminium and production of double aluminium-gallium salt at the gallium to alumina weight ratio comprising more than 1:340. Then, double aluminium-gallium salt is added to sodium hydroxide so that an alkali solution containing gallium and aluminium is obtained, and an electrolysis of the alkali solution containing gallium and aluminium is performed so that metallic gallium is obtained.

EFFECT: simplifying process and increasing gallium extraction degree.

20 cl, 3 dwg, 1 tbl, 10 ex

The technical field

The present invention relates to a method of extraction of metal gallium of fly ash and, in particular, relates to a method of extraction of metal gallium of fly ash generated in circulating fluidized bed.

The level of technology

Gallium is an important and widely used semiconductor material. The cost of gallium on the international market is very high and, respectively, gallium has a brilliant future. But stocks of gallium limited, its content in the earth's crust is only approximately 0.015 percent. Gallium almost no forms minerals, but there are other minerals in the form of isomorphism. Therefore, gallium much more difficult. In nature gallium often found in minerals together with aluminium and zinc. Essentially, sulfide deposits of zinc and ores are the main source for the extraction of gallium. Currently, more than 90% of gallium in the world derive from a by-product in the production of alumina in which the bauxite is used as the primary raw material. As a stock solution used for the enrichment and separation of gallium, use the mother solution, resulting in the deposition of carbon (or deposition using seed) during the production of alumina. The main component of this stock solution, resulting in the deposition of carbon (or deposition using seed), is the main solution sodium, containing gallium. The main methods of extraction of gallium from the specified main solution include a method for removal of aluminium using the limy test and carbonization method dealumination by way of two-stage decomposition lime milk, method of deposition and the method of adsorption resin growing in recent years.

Recent studies have shown that fly ash obtained from some places, contains a large number of gallium, which even exceeds the level of gallium in mineral deposition. During the research it was confirmed that the contents of gallium in fly ash is usually 12-230 mcg/g compared with the contents of gallium in other sources of fly ash quite deserve to be used as raw material for the extraction of metallic gallium. Taking into account the different conditions of calcination, fly ash classified as ash produced in coal-fired boilers, and ash produced in the circulating fluidized bed. Fly ash produced in coal-fired boilers, obtained by burning coal at very high temperatures (1400-1600°C), in which the clay is in the glassy state or is present in the form of mineral forms of mullite crystals or corundum crystals in hot metal mineral that makes such alumina very stable. The temperature of the combustion fly ash formed in circulating fluidized bed, much lower than the temperature of the traditional fly ash generated in coal-fired boilers, and is only about 850 OC C. Different temperature, cause significant difference of the phase composition of fly ash generated in coal-fired boilers, and fly ash formed in the circulating fluidized layer, that is, amorphous kaolinite is in the primary phase composition of fly ash generated in circulating fluidized bed in which silica, alumina and iron oxides possess a distinct activity.

In CN 200810051209.5 describes how to extract, as of alumina and gallium from fly ash. In the specified method, the solution sodium, containing gallium, receive ways acid leaching and alkaline leaching, and then enrich and separate gallium in the multistage process of carbon deposition and dissolution of sodium hydroxide.

In CN 200710065366.7 describes how to retrieve silica, alumina and gallium oxide of fly ash with a high content of alumina. The method involves the processing stage of the residue obtained after extraction of silicon dioxide from fly ash, to obtain a solution sodium, containing gallium, apply such solution as a stock solution for the enrichment of gallium in the multistage process of carbon deposition and dissolution of sodium hydroxide and in the process of adsorption on the pitch.

In CN 200710145132.3 describes a method for gallium and alumina. The method includes the stage of processing of fly ash to obtain a solution sodium, containing gallium, enrichment of gallium in the system of dissolution Bayer and then the separation of enriched gallium using the adsorption process using resin.

In CN 200710141488. describes a method for gallium. The intermediate product, i.e. the mother solution, resulting in the deposition of carbon in the process of production of alumina from fly ash is used as a raw material and subjected interaction with sodium bicarbonate, and then complete carbonation to obtain the concentrate gallium.

In the above documents, the mother solution, resulting in the deposition of carbon (or deposition using seed) during the production of alumina from the fly ash used as a feed material for enrichment and separation of gallium, that is, the mother solution, used for the extraction of gallium, is the main solution sodium, containing gallium.

In CN 200810017872.3 describes how to extract gallium of fly ash and coal gangue. In the process, used adsorption method with the use of absorption columns for the extraction of gallium aluminum chloride solution containing gallium, obtained by mixing of fly ash and sodium carbonate, calcination of this mixture with the subsequent water leaching and precipitation of carbon, and then interact with hydrochloric acid. The process of fly ash and sodium carbonate are mixed and ignited before the acid leaching at a very high temperature, suitable for extraction of gallium generated in coal-fired boilers ash with low activity.

Jiazhen Not al. reported on a study of the method of re-use of gallium from fly ash" (Scientific Research, 2002, No.5, P23-26), in which the fly ash reacts directly with the hydrochloric acid of obtaining aluminum chloride solution containing gallium, without annealing at a very high temperature and with the subsequent extraction of gallium by adsorption on the pitch. The reaction temperature of fly ash and low hydrochloric acid (60 C), which leads to low efficiency of leaching of gallium (35,2%). In addition, the resin used in the specified way to extract, is a (levextred) resin (CL-TBP). The mechanism of adsorption of this resin is similar to the mechanism of extracting solvent. Specified resin produced by polymerization and curing active group of extraction agent with the main resin. As a result, the effectiveness of adsorption resin is very low, and the cost is very high.

Short description of the invention

The objective of this invention is to provide an improved way of extraction of metal gallium of fly ash generated in circulating fluidized bed.

Method of extraction of metal gallium of fly ash generated in the circulating boiling layer according to the present invention, includes the following stages:

a) grinding of fly ash up to 100 mesh size or less, removal of iron by wet magnetic separation, so that the content of iron oxides in fly ash is reduced to 1.0 wt% or less, then adding hydrochloric acid in fly ash for the reaction of acid leaching, and exposure of the reaction product separation of the solid and liquid phase with the product receipt of leaching, which has a pH of 1 to 3;

b) gallium contained in the product leaching, by passing it through a column filled macroporous cation resin; and when you reach the saturation of adsorption, elution water column or hydrochloric acid as agent with obtaining eluent;

c) adding sodium hydroxide solution in eluent, Department of rainfall after the reaction by filtering for removal of iron in the solution sodium;

d) exposure solution sodium carbonization by introducing carbon dioxide followed by separation of gallium from the most part of aluminium and the receipt of a double salt gallium and aluminum with the ratio of the mass of gallium to alumina, constituting more than 1:340; and

e) add a received a double salt gallium and aluminum in sodium hydroxide solution, with the subsequent evaporation and concentration of the reagent with the receipt of the main a solution containing gallium and aluminum, with contents of gallium and alumina, amounting to 1 mol/l, respectively, and then carrying out the electrolysis of the stock solution with production of metal gallium.

Method according to the present invention will be described in detail below, but the present invention is not limited to the specified description.

Magnetic separator is used for fly ash, preferably represents a vertical circular magnetic separator. Even more preferably, vertical ring magnetic separator contains a rotating ring, inductive funds, top yoke of iron, lower yoke of iron, magnetic field coil, inlet, tail pallet and flushing device for washing the water inlet is used for the supply of coal ash to be , tail pallet is used to unload it nonmagnetic particles after deironing, upper yoke of iron and lower yoke of iron are, respectively, on the inner and outer sides of the bottom of the rotating ring, flushing device for washing water is located above the rotating ring, inductive tools are located in the rotating ring magnetic field coil is located on the periphery of the top of the iron yoke and lower the iron yoke so that the upper yoke and the lower yoke form a couple of magnetic poles for the generation of magnetic fields in the vertical direction, and inductive means represents layers of grids made of sheet steel, with each net of sheet steel interwoven with the help of wire, the edge of which have prismatic sharp corners.

Upper yoke of iron and lower yoke of iron preferably implemented as a whole and is located in a plane perpendicular to the rotating ring, so that encircle the inside and outside of the bottom of the rotating ring.

Vertical ring magnetic separator preferably additionally contains a water jacket with cameras for pressure compensation located near to the magnetic excitation coil.

Net of sheet steel preferably made of 1Cr17.

Magnetic field coil preferably represents the solenoid of the flat aluminum wire with double glass shell.

The average distance between the layers of mesh, sheet steel preferably from 2 to 5 mm is preferable to the average distance between the layers of mesh, sheet steel is 3 mm

Height of a grid of steel sheet preferably from 0,8 to 1,5 mm, the size of the holes of the grid is from 3 mm x 8 mm to 8 mm x 15 mm, and the thickness of the wire is from 1 to 2 mm Preferably, if the thickness of the grid sheet steel is 1 mm, the size of the holes of the grid is 5 mm x 10 mm, and the thickness of the wire is 1.6 mm

Vertical ring magnetic separator preferably additionally contains a pulsating mechanism associated with the tail pallet by means of a rubber.

Inductive means preferably placed around the entire circumference of the rotating ring.

When applying the above vertical circular magnetic separator for magnetic separation to deironing, it is necessary to determine the content of iron in the suspension subjected to magnetic separation. When the content of iron in the suspension equal to or lower than the given value, the uploading suspension; if the content of iron in the suspension above the setpoint, the suspension return to the loading hole for an additional magnetic separation. Such magnetic separation can be repeated 2 to 4 times, preferably, from 2 to 3 times.

Preferably, if the separation of suspensions in a magnetic field in a vertical circular magnetic separator specified separator provides magnetic field strength 15000 GS or more, even more preferably from 15,000 to 20,000 Gauss, more preferably to 17500 15000 TOS.

At the stage of (a) according to one of the embodiments of the present invention, filtration sludge ash formed in circulating fluidized bed, subjected to magnetic separation, placed in acid-resistant reactor and then add in it hydrochloric acid with the preferred concentration of 20 to 37% of mass for the reaction of acid dissolution. According to their preferred option for the implementation of the present invention, the molar ratio of HCl contained in hydrochloric acid, alumina, contained in fly ash, ranges from 4:1 to 9:1; fly ash and hydrochloric acid react with a temperature range of from 100 up to 200 C and at a pressure in the range from 0.1 to 2.5 MPa and reaction time is from 0.5 to 4.0 hours; then the reaction product is subjected to the separation of the solid and liquid phase and washed with obtaining product leaching, which has a pH of 1 to 3. The process of separation of the solid and liquid phase can be any of the conventional methods, such as separation by sedimentation, vacuum filtration, filtration under pressure or centrifugation or similar

At the stage of (b) according to one of the embodiments of the present invention, the said macroporous cationic resin preferably represents any resin, selected from the D001, 732, 742, 7020, 7120, JK008 and SPC-1.

At the stage of (b) according to one of the embodiments of the present invention, the said macroporous cationic resin may be a cation resin, such as styrene resins and acrylic resin. Substantial important technical characteristics of the resin include moisture from 50.5 to 70,0%, exchange capacity 3,60 mmol/g or more, volumetric exchange capacity of 1.2 mmol/g or more, bulk density wet from 0.6 to 0.80 g/ml, particle size range 0.315 up to 1,250 mm, the actual size of the particles from 0.400 to 0,700 mm and maximum operating temperature of 95 degrees C.

Gallium contained in the product leaching received at the stage of (a), is adsorbed by passing it through a column filled macroporous cation resin. The process of adsorption can be any of the conventional ways. However, it is preferable to conduct the adsorption in such a way that the product through the column with the resin from the bottom up at temperatures from 20 up to 90 degrees C, so sour filtrate moves up the emptiness in the resin like a piston with a volumetric flow 1-4 times the volume flow of resin per hour. Column with the resin can be a single column or two columns, arranged in tandem. At this stage, while the enrichment of gallium in the product account of its absorption of macroporous cation resin, simultaneously flows effective adsorption of iron in the product leaching, so get purified solution of aluminum chloride with low iron content, which can then be used to obtain crystalline aluminum chloride and metallurgical alumina with low iron content.

cation resin can be eluted using agent with obtaining eluent when reaching saturation adsorption. agent preferably represents water or 2-10 mass.% hydrochloric acid. Conditions elution may include the following: temperature elution is from 20 to 60 C, the number of agent in 1-3 times the amount of resin volumetric flow agent in 1-3 times exceeds the volume flow of resin per hour, and agent elution under gradient conditions passes through the column with the resin from the top down.

Restore the adsorption capacity of macroporous cation resin by regeneration. Resin can be regenerated using 2-10 mass.% hydrochloric acid. The regeneration temperature ranges from 20 to 60 C, the amount of hydrochloric acid in 1-2 times the amount of resin, the volume flow of hydrochloric acid in 1-3 times exceeds the volume flow of resin per hour, hydrochloric acid passes through the specified column with the resin from the top down.

On the stage) according to one of the embodiments of the present invention, sodium hydroxide solution is added in the eluent with stirring, the ratio of the weight of alumina in to sodium is from 1:1 to 2:1, eluent reacts with sodium hydroxide solution at a temperature from 20 to 100 C, so chloride, aluminium and gallium chloride contained in , react with sodium hydrochloride with education sodium/ sodium chloride iron is deposited in the form of iron hydroxide. The reaction product is subjected to the separation of the solid and liquid phase and washed with obtaining solution sodium. Concentration of a solution of sodium hydroxide, used on stage), preferably from 180 to 240 g/HP

At the stage d) according to one of the embodiments of the present invention, the right amount of carbon dioxide can be downloaded in solution sodium for holding carbonization one or more times until the ratio of the mass of gallium and alumina received a double salt gallium and aluminum did not exceed 1:340. In particular, carbonization (carbonization) may include the following stages.

Primary carbonization: carbon dioxide is injected at a flow rate of 80-160 ml/min in mother liquor sodium for a smooth carbonization, in which the temperature of the reaction regulate in the range from 40 up to 90 degrees C and carbonization is from 4 to 10 hours, the pH in the end of the reaction is 10.6-9,7. After the reaction, most of the aluminum is deposited in the form of aluminum hydroxide, while gallium held in solution. The precipitate is removed from the solution for the separation of gallium and most of aluminum for the first time;

If the ratio of the mass of gallium and alumina in a double salt gallium and aluminum, obtained in primary and secondary , equal to, or less than 1:340, such a double salt can be dissolved in a solution of sodium hydroxide or uterine solution sodium for re-evaluation of the initial carbonization and secondary carbonization until the ratio of the mass of gallium and alumina in a double salt gallium and aluminum did not exceed 1:340. The contents of gallium is measured values according to the method described in the Standard of people's Republic of China GB/T 20127.5-2006 "Steel and Alloy - Determination of Trace Elements Contents Part V: Determination of Gallium Content by Extraction Separation-Rhodamine In Photometric Method". The content of aluminum hydroxide is calculated as 100% minus the measured content of gallium, which is then recalculated on the content of alumina. In the present invention, aluminum hydroxide and sodium carbonate, received at the stages of enrichment and separation of gallium can be reused as a by-product.

At the stage of (e) as one of the embodiments of the present invention, a double salt gallium and aluminum, obtained at secondary carbonization, add in a solution of sodium hydroxide with obtaining basic solution containing gallium and aluminum. The concentration of sodium hydroxide solution preferably from 180 to 245 g/HP As the contents of gallium and content of sodium mainly solution set equal to 1 mol/l or more by way of regulation of alkalinity and/or concentration. Then, the main solution is electrolyzed using platinum electrodes used as the negative and positive electrodes at a current electrolysis of 180-200 mA/l, voltage electrolysis of 4, and the temperature of the electrolytic bath, component 35-45°C, to produce metallic gallium product.

The reaction temperature sludge double salt gallium and aluminum hydroxide solution sodium preferably from 20 to 100 degrees C.

In the present invention, sodium salts contained in solution at high concentrations can be recycled by evaporation, with the evaporated water can be reused.

Compared with the processes in the prior art, the method according to the present invention is simple, the degree of extraction of gallium high, the cost of production is low and stable quality of products. Produced in the circulating fluidized layer of fly ashes with high activity used in the present invention as a raw material and gallium extracted from fly ash using the direct acid leaching process to get rid of the stage of the annealing and activation in the presence of sodium carbonate at high temperature and, thus, facilitates technological processes and reduces costs. Acid leaching of fly ash occurs in reactor at moderate temperature (in the range from 100 up to 200 C), and consequently, the efficiency of leaching gallium high and amounts to 80% or more. Effective efficiency adsorption of gallium in the product 96% or more when using adsorption gallium cheaper macroporous cation resin. The enrichment of gallium in the product application of macroporous cation resin is effective removal of iron contained in the product leaching, with the processed aluminum chloride solution with low iron content, which can be used to obtain crystalline aluminum chloride and metallurgical alumina with low iron content.

In addition, experimental study showed that because they use the device for separation in a magnetic field according to the present invention, the efficiency of removal of iron is improved by 20% or more, and the rate of removal of iron increases from 60% to 80%), that considerably reduces expenses in the course of deferrization solution in subsequent processes, and thus reduces cost and increases production efficiency.

Brief description of drawings

Figure 1 shows a block diagram of the method according to the present invention;

Figure 2 shows a block diagram of multistage process of carbonization according to the present invention;

Figure 3 shows a schematic image of a vertical circular magnetic separator used according to one of the preferred options for the implementation of the present invention.

A detailed description of the present invention

Next method according to the present invention will be described in detail with reference to the drawings, but one must understand that the present invention is not limited to them in any way.

The structure of the vertical circular magnetic separator used in the following examples, shown in figure 3. Vertical ring magnetic separator contains a rotating ring 101, inductive means 102, upper yoke of iron 103, lower yoke of iron 104, magnetic field coil 105, filling opening 106 and tail pallet 107, and also includes the pulsating mechanism 108 and sedimentation device for flushing water 109.

Electric motor or other drive unit can supply the rotating ring 101 energy so that the ring 101 can rotate with the set speed.

If the settings such as iron content or amount of material being processed, are below the set value, you can use a relatively low speed, such as 3.min, thanks to which the ferromagnetic impurities have enough time for on the grid inductive funds under the action of magnetic field and separation.

Inductive funds 102 located in the rotating ring. The magnetic field generated magnetic excitation coil 105, turns the upper yoke of iron

103 and lower yoke of iron 104 in a couple of magnetic poles, generating a magnetic field in a vertical direction. Upper yoke of iron 103 and lower yoke of iron

104 are located on the inner and outer sides of the bottom of the rotating ring 101, so that the rotating ring 101 rotates vertically between magnetic poles. During the rotation of a rotating ring 101, inductive means 102 in the ring 101 will pass through a couple of magnetic poles, educated upper iron yoke 103 and lower the iron yoke 104 and be magnetization for removal of iron.

Inductive means 102 may constitute layers of grids made of sheet steel. The grid made of sheet steel made of 1Cr17. Each grid layer of sheet steel gossip using wire, and knitted mesh has a diamond shape. The edges of the wire have prismatic sharp corners. Upper yoke of iron 103 reported with the charging hole 106, and the lower yoke of iron 104 reported with a tail pallet 107, which is used for unloading materials. The average distance between the layers grids of steel plates is 3 mm Magnetic field coil 105 is a solenoid of flat aluminum wire with double glass-coated, and represents a solid wire. The current passing through the magnetic field coil 105, smoothly regulate, and consequently, to smoothly regulate the strength of the magnetic field generated by the magnetic coil 105.

Vertical ring magnetic separator additionally contains a pulsating mechanism 108 associated with a tail pallet 107 through the rubber 111. The pulsating mechanism may operate due to the eccentric lever mechanism, so that the alternating power generated by the pulsating mechanism 108, the pressure on the rubber plate 111, forcing it to move forward and back, the mineral suspension in the tail pallet 107 can create a ripple.

Control unit for water flushing 109 located over the rotating ring 101, and is designed for rinsing of magnetic particles in the hopper for concentration under action of a stream of water. Flushing flushing device water-109 may be suitable wash or spray device, such as a spray nozzle, water pipe, etc.

Filling opening 106 reported with the lateral surface of the top of the iron yoke 103, so that the fly ash can pass through the rotating ring. Filling opening 106 can be a hopper or boot pipe. Filling opening 106 done with the possibility of submitting mineral suspensions, so that the mineral suspension comes into the upper yoke of iron 103 from relatively small height for prevention of penetration of the magnetic particles in inductive means 102 due to gravity, which improves so the result of magnetic separation and removal of impurities.

Vertical ring magnetic separator additionally contains a cooling unit 112, which is set near the magnetic excitation coils to reduce its operating temperature. The cooling unit is a water jacket with cameras for pressure compensation. Water jacket with cameras for pressure compensation is made of stainless steel, and thus not showing a tendency to form scale. Since the camera for pressure set, respectively, at the inlet and outlet of the water jacket, they provide the uniform passage of water through each layer of the water jacket and filling up of all its inner space, thus preventing leakage of local water along the shortest path, otherwise, would affect the heat dissipation. Each layer of the water jacket has a water pipeline with a large cross-sectional area, thus, allows to avoid clogging due to the formation of scale. Even if somewhere there is a blockage, it will not affect the normal course of circulating water in the water jacket. In addition, the water jacket is in close contact with the coil due to the large contact area, respectively, most of the heat generated by the coil can be prevented with a stream of water.

Compared with conventional hollow copper tube for heat dissipation, water jacket with cameras for pressure compensation is characterized by high efficiency of heat dissipation, small temperature rise of the winding and low power excitation. In the case of nominal excitation current, equal 40A, the power of the magnetic separator is equipped with a water jacket with cameras for pressure compensation for heat dissipation can be reduced from 35 to 21 kW kW.

When working magnetic separator supplied mineral suspension runs along the top slots of the iron yoke of 103, and then through the rotating ring 101. Since inductive means 102 in the rotating ring 101 magnetized in a background magnetic field on the surface of the inductive funds 102 formed the magnetic field of high-power magnetic induction (such as 22000 HS). Under the influence of very strong magnetic field magnetic particle suspension in mineral stick to the surface of inductive funds 102 and rotate with a rotating ring 101, moving on the site without the magnetic field at the top of the rotating ring 101. Then, magnetic particles are washed down the bunker for concentration with washing device for flushing water 109 above the top of the rotating ring. Nonmagnetic particles pass along the slot bottom of the iron yoke of 104 in the tail pallet 107 and further are discharged through the tail output the tail pallet 107.

Next method according to the present invention will be described in detail with reference to examples, however, it should be understood that the present invention is not limited to them in any way.

In the following examples, fly ash produced in the circulating fluidized bed and throwing away the heat and power plant, used as a raw material, chemical ingredients such ash are shown in table 1. The contents of gallium in fly ash is 0,0042 wt.%

Table 1.

The chemical components of fly ash generated (circulating fluidized bed wt.%)

SiO 2 Al 2 O 3 TiO 2 CaO MgO

TFe 2 O 3

FeO K 2 O Na 2 O LOS SO 3 Just 34,70 46,28 1,48 3,61 0,21 1,54 0,22 0,39 0,17 7,17 1,32 95,77

Example 1

In the example following the procedure of the experiment.

(1) Fly ash produced in the circulating fluidized bed, crushed to the size of the 200 mesh, iron removed by wet magnetic separation, using vertical magnetic separator, depicted in figure 3, so that the content of iron oxide in fly ash decreased to 0.8%of mass; placed filtration sludge ash obtained after magnetic separation, acid-resistant the reactor and add technical hydrochloric acid with a concentration of 37% of mass for the reaction of acid dissolution, the molar ratio of HCl contained in hydrochloric acid, alumina, contained in the fly ash was of 4.5:1, the reaction temperature was 200 degrees C, the reaction pressure was 2.1 MPa and reaction time was 1 hour; and then filtered off under pressure paged reaction product with the use of frame filter press and washed with obtaining product leaching the pH of 1.7, and the efficiency of leaching of gallium from fly ash was measured and amounted to 84.2%.

(2) the Product at the expense of heat transfer to a temperature of 65 C and then with the use of corrosion-resistant pump have downloaded a product leaching in the column with the resin (one column, filled with resin D001 (Anhui Wandong Chemical Plant) for the enrichment of gallium, and the consumption of the product leaching in 2 times exceeded the volume flow of resin per hour; and when reaching saturation adsorption column was eluted with a resin, using 4 wt.% hydrochloric acid as agent, at 25 C with obtaining enriched gallium eluent, the consumption of hydrochloric acid in 2 times exceeded the volume flow of resin per hour, and the total number of agent, used for the elution, in 2 times exceeded the amount of resin; and were regenerating resin, using 4 wt.% hydrochloric acid, and the efficiency of the adsorption of gallium in an acidic solution was measured and accounted for 96.4 per cent.

(3) was Added to the eluent-180 g/l sodium hydroxide solution, so that the mass ratio of alumina to sodium in solution was to 1.0, and in support of a chemical reaction at 20 C, were the product of the reaction filtering for sludge removal iron hydroxide with obtaining solution sodium.

(5) Added a double salt aluminium and gallium obtained at the stage of (4), in sodium hydroxide solution with a concentration of 180 g/l and supported reaction at 25 C with obtaining basic solution enriched gallium, then regulate the contents of gallium up to 1.5 mol/l and subjected to electrolysis using platinum electrodes as the negative and positive electrodes current electrolysis was 200 mA/l, voltage electrolysis amounted to 4 and the temperature of the electrolytic bath was 40 C, with the receipt of the product in the form of a metallic gallium. The contents of gallium in the product has been measured according to the method described in "YS/T520-2007 Methods for Chemical Analysis of Gallium", and amounted to 99.9%.

Example 2

Working conditions were the same as described in example 1, except for stage (1). Stage (1) has been amended as follows:

Fly ash produced in the circulating fluidized bed, crushed to the size of 150 mesh, iron removed by wet magnetic separation, using vertical magnetic separator, depicted in figure 3, so that the content of iron oxide in fly ash decreased to 0.8%of mass; placed filtration sludge ash obtained after magnetic separation, acid-resistant reactor and add technical hydrochloric acid with a concentration of 28% of mass for the reaction of acid dissolution, the molar ratio of HCl contained in hydrochloric acid, alumina, contained in fly ash, was 5:1, the reaction temperature was 150 C, the reaction pressure was 1,0 MPa and reaction time was 2 hours and then filtered off under pressure paged reaction product with the use of frame filter press and washed with obtaining product leaching the pH 1.5, and the efficiency of leaching of gallium from fly ash was measured and accounted for 82.8%.