Device and method for strengthening dissolution of aluminum oxide in bauxite

Abstract

The invention belongs to the field of hydrometallurgy, and particularly relates to a device and method for strengthening dissolution of aluminum oxide in bauxite. The invention provides a device for intensifying dissolution of aluminum oxide in bauxite. The device comprises a reaction tank, a first spiral pipe, an ultrasonic intensifying pipeline, a pump, a second spiral pipe, a filtering device, a first ultrasonic system and a second ultrasonic system, the reaction tank is divided into a first dissolution chamber and a second dissolution chamber; the first ultrasonic system is arranged between the first dissolution chamber and the second dissolution chamber, and the second ultrasonic system is arranged at the bottom of the ultrasonic strengthening pipeline; a first discharge hole formed in the first dissolution chamber is communicated with a first spiral pipe, an ultrasonic strengthening pipeline, a second spiral pipe and a second feed hole formed in the second dissolution chamber in sequence; a filtering device is arranged in the second dissolution chamber and is connected with the second feeding hole; the pump is arranged at the joint of the ultrasonic strengthening pipeline and the second spiral pipe. The device for strengthening dissolution of aluminum oxide in bauxite provided by the invention can improve the relative dissolution rate of aluminum oxide.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a device and a method for strengthening the dissolution of aluminum oxide in bauxite. Background Art

[0002] Alumina is an important raw material for the aluminum industry, and its demand is closely related to the production and application of aluminum. Bauxite is the only ore source for the production of alumina. The world's bauxite resources include gibbsite, diaspore-type bauxite and refractory diaspore-type bauxite. Diaspore-type bauxite has perfect crystallization, dense structure, harsh dissolution conditions and high production cost. Therefore, the art urgently needs a method for strengthening the dissolution of diaspore-type bauxite to improve the dissolution effect of alumina and reduce production costs.

[0003] High-titanium bauxite is a diaspore-type bauxite with a titanium content of more than 3-7%. The traditional technology generally adds 8-15% lime to the raw slurry of high-titanium bauxite to generate perovskite precipitation, thereby eliminating the blocking effect of titanium minerals on dissolution and preventing titanium minerals from wrapping the diaspore-type bauxite, resulting in almost no dissolution of alumina; and the higher the titanium mineral content of the bauxite, the more lime is added. However, adding a large amount of lime will lead to a series of hazards, mainly: (1) the generation of a large amount of hydrated garnet (3CaO·Al 2 O 3 ·xSiO 2 (6-2x)H 2 (0) leads to a large loss of alumina; (2) calcium carbonate impurities in lime are brought into the system, increasing the impurities in the system; (3) the amount of red mud is increased; (4) a large amount of calcium-containing phases wrap the hematite in the red mud, significantly reducing the iron recovery rate in the red mud, reducing the quality of iron concentrate, and is not conducive to the comprehensive utilization of red mud. Therefore, there is an urgent need in the art for a method to enhance the dissolution of high-titanium bauxite, solve the dissolution retardation effect of titanium minerals, and reduce the amount of lime added.

[0004] At present, many scholars have carried out a lot of research work to find ways to strengthen the effective dissolution of high-titanium bauxite, including roasting activation or introducing activator additives, which can improve the dissolution performance of high-titanium bauxite, reduce the dissolution temperature, and shorten the dissolution time. However, the dissolution rate is generally between 60% and 90%. Generally speaking, the dissolution rate of high-titanium bauxite is still relatively low. Summary of the invention

[0005] The object of the present invention is to provide a device and method for strengthening the dissolution of aluminum oxide in bauxite. The device provided by the present invention can increase the relative dissolution rate of aluminum oxide in bauxite.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A device for strengthening the dissolution of aluminum oxide in bauxite, comprising at least one reaction unit, each of which independently comprises a reaction tank, a first spiral tube 4, an ultrasonic strengthening pipeline 5, a pump 22, a second spiral tube 6, a filtering device 8, a first ultrasonic system 10 and a second ultrasonic system 11;

[0008] The reaction tank is divided into a first dissolution chamber 2 and a second dissolution chamber 9; the first dissolution chamber 2 and the second dissolution chamber 9 are connected at the top; the first ultrasonic system 10 is arranged between the first dissolution chamber 2 and the second dissolution chamber 9, and the second ultrasonic system 11 is arranged at the bottom of the ultrasonic enhancement pipeline 5;

[0009] The first dissolution chamber 2 is provided with a first discharge port 3, and the second dissolution chamber 9 is provided with a second feed port 7. The first discharge port 3, the No. 1 spiral tube 4, the ultrasonic enhanced pipeline 5, the No. 2 spiral tube 6 are connected with the second feed port 7 in sequence, and the second dissolution chamber 9 is provided with the filtering device 8; the filtering device 8 is connected to the second feed port 7; the pump 22 is arranged at the connection between the ultrasonic enhanced pipeline 5 and the No. 2 spiral tube 6.

[0010] Preferably, the first ultrasonic system 10 and the second ultrasonic system 11 independently include a shell 16, a plurality of piezoelectric ceramic vibrators 14, a plurality of amplitude transformers 13 and a plurality of ultrasonic probes 15; the shell 16 is a double-layer sleeve structure, including an outer cylinder and an inner cylinder sleeved inside the outer cylinder, the central axes of the inner cylinder and the outer cylinder coincide, and an ultrasonic cavity 17 is formed between the inner cylinder and the outer cylinder; the plurality of piezoelectric ceramic vibrators 14, the plurality of amplitude transformers 13 and the plurality of ultrasonic probes 15 are arranged in the ultrasonic cavity 17.

[0011] Preferably, the amplitude transformer 13 is arranged on the outer surface of the inner cylinder of the shell 16, the piezoelectric ceramic vibrator 14 is arranged on the amplitude transformer 13, the ultrasonic probe 15 is arranged on the piezoelectric ceramic vibrator 14, and the ultrasonic probe 15 is connected to the inner surface of the outer cylinder of the shell 16.

[0012] Preferably, the filtering device 8 includes a filter plate 20 and a filter cloth 21 which are stacked, the material of the filter plate 20 includes a high-strength and wear-resistant composite material, and the high-strength and wear-resistant composite material includes polypropylene, a diaphragm or rubber; the material of the filter cloth 21 includes synthetic fibers, and the synthetic fibers include polyester, polypropylene, nylon or vinylon, and the pore size of the filter cloth 21 is <100 μm.

[0013] Preferably, the No. 1 spiral tube 4 and the No. 2 spiral tube 6 independently include a solid cylinder, a spiral blade channel 19 arranged around the solid cylinder and an outer wall of the spiral tube; the outer side of the spiral blade channel 19 is connected to the inner surface of the outer wall of the spiral tube, and the inner side of the spiral blade channel 19 is connected to the outer surface of the solid cylinder; the space formed between the solid cylinder, the spiral blade channel 19 and the outer wall of the spiral tube is the slurry flow space 18, and the pitch is 5 dm to 1 m.

[0014] Preferably, when there are multiple reaction units, the multiple reaction units are arranged in series; the first dissolution chamber 2 is provided with a first feed port 1, and the second dissolution chamber 9 is provided with a second feed port 12; the series connection of the multiple reaction units is that the second feed port 12 of the first reaction unit is connected to the first feed port 1 of the next reaction unit.

[0015] The present invention provides a method for dissolving alumina in fortified bauxite using the above device, comprising the following steps:

[0016] Mixing bauxite, lime and alkaline solution to obtain raw ore slurry, placing the raw ore slurry in the first dissolution chamber 2 for first ultrasonic enhanced dissolution to obtain first ultrasonic enhanced slurry;

[0017] The first ultrasonic enhanced slurry enters the ultrasonic enhanced pipeline 5 through the first discharge port 3 and the first spiral tube 4, and performs a second ultrasonic enhanced dissolution in the ultrasonic enhanced pipeline 5 to obtain a second ultrasonic enhanced slurry;

[0018] The second ultrasonic strengthening slurry enters the filtering device 8 through the second spiral tube 6 and the second feed port 7 for filtration to obtain a filter cake and a filtrate respectively;

[0019] The filtrate enters the second dissolution chamber 9 for the third ultrasonic enhanced dissolution; the filter cake enters the first dissolution chamber 2 for the first ultrasonic enhanced dissolution.

[0020] Preferably, the ultrasonic power density of the first, second and third ultrasonic enhanced dissolution is independently 0.1 to 1500 KW / m 3 , the ultrasonic frequency is 20~2000KHz.

[0021] Preferably, the temperature of the slurry in the reaction tank is 50-500° C., the pH value of the slurry is 8-14, and the working pressure of the pump 22 is 1000-10000 psi.

[0022] Preferably, the bauxite includes high-titanium bauxite, the mass of titanium dioxide in the high-titanium bauxite is 3-7%; the amount of lime added is 6-12wt% of the bauxite; the mass ratio of the alkaline solution to the bauxite is 2.4-4.8:1, and the solid content of the original ore slurry is 250-350g / L.

[0023] The present invention provides a device for strengthening the dissolution of alumina in bauxite, comprising at least one reaction unit, each of which independently comprises a reaction tank, a No. 1 spiral tube 4, an ultrasonic strengthening pipeline 5, a pump 22, a No. 2 spiral tube 6, a filtering device 8, a first ultrasonic system 10 and a second ultrasonic system 11; the reaction tank is divided into a first dissolution chamber 2 and a second dissolution chamber 9; the first dissolution chamber 2 and the second dissolution chamber 9 are connected at the top; the first ultrasonic system 10 is arranged between the first dissolution chamber 2 and the second dissolution chamber 9, and the second ultrasonic system 11 is arranged at the bottom of the ultrasonic strengthening pipeline 5; the first dissolution chamber 2 is provided with a first discharge port 3, and the second dissolution chamber 9 is provided with a second feed port 7, the first discharge port 3, the No. 1 spiral tube 4, the ultrasonic strengthening pipeline 5, the No. 2 spiral tube 6 and the second feed port 7 are connected in sequence, and the filtering device 8 is arranged in the second dissolution chamber 9; the filtering device 8 is connected to the second feed port 7; the pump 22 is arranged at the connection between the ultrasonic strengthening pipeline 5 and the No. 2 spiral tube 6. The present invention couples ultrasound with filtering technology, and applies ultrasound technology as an auxiliary removal device to bauxite dissolution. Ultrasonic waves can effectively improve the solid surface structure to form a new reaction interface, accelerate the cross-phase diffusion transfer between the solid and liquid phases, and then obtain more effective alumina solute transfer, which is beneficial to reduce the solute diffusion resistance, make the reaction solution more uniform, and improve the diffusion control and reaction rate control of the solid-liquid leaching process; ultrasound can also increase the specific surface area of ​​particles, strengthen the chemical reaction between the solid and liquid phases, accelerate the reaction rate, and optimize the reaction process; the spiral tube effectively forms turbulence based on the internal spiral blade channel, prolongs the reaction path, and simultaneously realizes the deep dissolution process, saving production space while shortening the reaction time; filtering technology can realize the diversion and recovery of reactants and dissolution solutions, and improve the comprehensive utilization efficiency of alumina. The device of the present invention uses unconventional metallurgical strengthening means (ultrasonic metallurgy) to strengthen the dissolution process, which can quickly and efficiently extract aluminum resources and improve the dissolution rate of alumina.

[0024] The present invention provides a method for strengthening the dissolution of aluminum oxide in bauxite, wherein bauxite, lime and alkaline circulating mother liquor are mixed to obtain raw ore pulp, and the raw ore pulp is placed in the first dissolution chamber for the first ultrasonic enhanced dissolution, and the raw ore pulp forms turbulence under the action of ultrasonic waves, reduces diffusion resistance, destroys the boundary layer, accelerates mass transfer, and breaks the wrapping of the sodium titanate film, refines the mineral particle size, and makes the alkali solution and aluminum oxide fully react; the first ultrasonic enhanced slurry enters the ultrasonic enhanced pipeline through the first discharge port and the No. 1 spiral tube, and under the action of the spiral and ultrasonic waves, a stronger turbulence is formed to achieve the second ultrasonic enhanced dissolution reaction; the second ultrasonic enhanced slurry enters the filtering device through the No. 2 spiral tube for filtration, and the filtrate enters the second dissolution chamber, and the third ultrasonic enhanced dissolution is carried out under the action of ultrasonic waves. The slurry after three ultrasonic enhanced reactions enters the next-level device or the next production process from the outlet of the second dissolution chamber. The dissolution method provided by the present invention has the characteristics of simple process flow, reliable operation, low energy consumption, and the final product is environmentally friendly and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a front view of the structure of the device for strengthening the dissolution of aluminum oxide in bauxite according to the present invention;

[0026] Figure 2 A three-dimensional schematic diagram of the structure of the device for strengthening the dissolution of aluminum oxide in bauxite according to the present invention;

[0027] Figure 3 A top view of the structure of the device for strengthening the dissolution of aluminum oxide in bauxite according to the present invention;

[0028] In the figure: 1-first feed inlet, 2-first dissolution chamber, 3-first discharge port, 4-No. 1 spiral tube, 5-ultrasonic strengthening pipeline, 6-No. 2 spiral tube, 7-second feed inlet, 8-filter device, 9-second dissolution chamber, 10-first ultrasonic system, 11-second ultrasonic system, 12-second discharge port, 13-amplifier, 14-piezoelectric ceramic vibrator, 15-ultrasonic probe, 16-housing, 17-ultrasonic cavity, 18-slurry flow space, 19-spiral blade channel, 20-filter plate, 21-filter cloth, 22-pump. DETAILED DESCRIPTION

[0029] The present invention provides a device for strengthening the dissolution of aluminum oxide in bauxite, comprising at least one reaction unit, each of which independently comprises a reaction tank, a No. 1 spiral tube 4, an ultrasonic strengthening pipeline 5, a pump 22, a No. 2 spiral tube 6, a filtering device 8, a first ultrasonic system 10 and a second ultrasonic system 11;

[0030] The reaction tank is divided into a first dissolution chamber 2 and a second dissolution chamber 9; the first dissolution chamber 2 and the second dissolution chamber 9 are connected at the top; the first ultrasonic system 10 is arranged between the first dissolution chamber 2 and the second dissolution chamber 9, and the second ultrasonic system 11 is arranged at the bottom of the ultrasonic enhancement pipeline 5;

[0031] The first dissolution chamber 2 is provided with a first discharge port 3, and the second dissolution chamber 9 is provided with a second feed port 7. The first discharge port 3, the No. 1 spiral tube 4, the ultrasonic enhanced pipeline 5, the No. 2 spiral tube 6 are connected with the second feed port 7 in sequence, and the second dissolution chamber 9 is provided with the filtering device 8; the filtering device 8 is connected to the second feed port 7; the pump 22 is arranged at the connection between the ultrasonic enhanced pipeline 5 and the No. 2 spiral tube 6.

[0032] The front view of the device structure for strengthening the dissolution of aluminum oxide in bauxite provided by the present invention is as follows Figure 1 The three-dimensional schematic diagram of the device structure is shown in Figure 2 The top view of the device structure is shown in Figure 3 As shown below; combined Figure 1 , Figure 2 and Figure 3 Provide detailed explanation.

[0033] As an embodiment of the present invention, a partition is provided in the reaction tank, and the reaction tank is divided into a first dissolution chamber 2 and a second dissolution chamber 9 by the partition; the bottom and side of the partition are respectively connected to the bottom and side of the reaction tank, and a gap is left between the top of the partition and the top of the reaction tank; the first ultrasonic system 10 is arranged on the wall surfaces on both sides of the partition; the filtering device 8 is connected to the second feed port 7 and the top of the partition, and the second feed port 7 is higher than the top of the partition.

[0034] As an embodiment of the present invention, the first ultrasonic system 10 and the second ultrasonic system 11 independently include a shell 16, a plurality of piezoelectric ceramic vibrators 14, a plurality of amplitude transformers 13 and a plurality of ultrasonic probes 15; the shell 16 is a double-layer sleeve structure, including an outer cylinder and an inner cylinder sleeved inside the outer cylinder, the central axes of the inner cylinder and the outer cylinder coincide, and an ultrasonic cavity 17 is formed between the inner cylinder and the outer cylinder; the plurality of piezoelectric ceramic vibrators 14, the plurality of amplitude transformers 13 and the plurality of ultrasonic probes 15 are arranged in the ultrasonic cavity 17.

[0035] As an embodiment of the present invention, the amplitude transformer 13 is arranged on the outer surface of the inner cylinder of the shell 16, the piezoelectric ceramic vibrator 14 is arranged on the amplitude transformer 13, the ultrasonic probe 15 is arranged on the piezoelectric ceramic vibrator 14, and the ultrasonic probe 15 is connected to the inner surface of the outer cylinder of the shell 16.

[0036] The present invention adopts ultrasonic coupling technology. Ultrasonic waves can effectively improve the solid surface structure to form a new reaction interface, accelerate the cross-phase diffusion transfer between the solid and liquid phases, and then obtain more effective alumina solute transfer, which is beneficial to reduce the solute diffusion resistance, make the reaction solution more uniform, and improve the diffusion control and reaction rate control of the solid-liquid leaching process; ultrasonic waves can also increase the specific surface area of ​​the particles, strengthen the chemical reaction between the solid and liquid phases, accelerate the reaction rate, and optimize the reaction process.

[0037] As an embodiment of the present invention, the filter device 8 includes a filter plate 20 and a filter cloth 21 which are stacked; the material of the filter plate 20 includes a high-strength wear-resistant composite material, specifically polypropylene, a diaphragm or rubber; the material of the filter cloth 21 includes a synthetic fiber, specifically polyester, polypropylene, nylon or vinylon, and the pore size of the filter cloth 21 can be less than 100 μm, specifically 1 to 80 μm. The filter device of the present invention can realize the diversion and recovery of reactants and dissolution liquid, and improve the comprehensive utilization efficiency of aluminum oxide.

[0038] As an embodiment of the present invention, the No. 1 spiral tube 4 and the No. 2 spiral tube 6 independently include a solid cylinder, a spiral blade channel 19 arranged around the solid cylinder, and an outer wall of the spiral tube; the outer side of the spiral blade channel 19 is connected to the inner surface of the outer wall of the spiral tube, and the inner side of the spiral blade channel 19 is connected to the outer surface of the solid cylinder; the space formed between the solid cylinder, the spiral blade channel 19 and the outer wall of the spiral tube is a slurry flow space 18, and the pitch is 5dm to 1m. The present invention is provided with a spiral blade pipeline, which can extend the reaction path, and can make the slurry effectively form turbulence in the slurry flow space along the spiral blade channel, and simultaneously realize the deep dissolution process, saving production space and shortening the reaction time.

[0039] As an embodiment of the present invention, a pump 22 is provided at the connection between the ultrasonic enhanced pipeline 5 and the No. 2 spiral tube 6; the two ports of the pump 22 are respectively connected to the pipe openings of the ultrasonic enhanced pipeline 5 and the No. 2 spiral tube 6. The pump provided in the present invention can provide a suitable pressure for the reaction tank, ensure that the slurry in the ultrasonic enhanced pipeline flows into the No. 2 spiral tube, and make the reaction proceed smoothly.

[0040] The device for strengthening the dissolution of alumina in bauxite provided by the present invention comprises at least one reaction unit. As an embodiment of the present invention, when there are multiple reaction units, the multiple reaction units are arranged in series; the first dissolution chamber 2 is provided with a first feed inlet 1, and the second dissolution chamber 9 is provided with a second discharge port 12; the series connection of the multiple reaction units can be that the second discharge port 12 of the first reaction unit is connected to the first feed inlet 1 of the next reaction unit.

[0041] The present invention provides a method for dissolving alumina in fortified bauxite using the above device, comprising the following steps:

[0042] Mixing bauxite, lime and alkaline solution to obtain raw ore slurry, placing the raw ore slurry in the first dissolution chamber 2 for first ultrasonic enhanced dissolution to obtain first ultrasonic enhanced slurry;

[0043] The first ultrasonic enhanced slurry enters the ultrasonic enhanced pipeline 5 through the first discharge port 3 and the first spiral tube 4, and performs a second ultrasonic enhanced dissolution in the ultrasonic enhanced pipeline 5 to obtain a second ultrasonic enhanced slurry;

[0044] The second ultrasonic strengthening slurry enters the filtering device 8 through the second spiral tube 6 and the second feed port 7 for filtration to obtain a filter cake and a filtrate respectively;

[0045] The filtrate enters the second dissolution chamber 9 for the third ultrasonic enhanced dissolution; the filter cake enters the first dissolution chamber 2 for the first ultrasonic enhanced dissolution.

[0046] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0047] In the present invention, bauxite, lime and alkaline solution are mixed to obtain raw ore slurry, and the raw ore slurry is placed in the first dissolution chamber 2 for first ultrasonic enhanced dissolution to obtain first ultrasonic enhanced slurry.

[0048] As an embodiment of the present invention, the bauxite can be a diaspore-type bauxite, specifically a high-titanium bauxite; the mass of titanium dioxide in the high-titanium bauxite is 3-7%; the particle size of the bauxite can be <150μm, and more than 75% of the bauxite has a particle size of <63μm.

[0049] As an embodiment of the present invention, the amount of lime added is 6-12wt% of the bauxite. As an embodiment of the present invention, the lime composition includes: 85%-95% CaO, 80%-92% CaO f ; Among them, CaO f Effective calcium refers to active calcium oxide excluding calcium carbonate, calcium silicate and other calcium salts in lime; CaO is total calcium, which refers to the total calcium oxide in lime, including both calcium oxide contained in raw lime burning and calcium oxide in overburned lime; the ratio of the lime component is that the mass ratio of calcium oxide to silicon dioxide in the original ore slurry after mixing is 0.8 to 1.2:1.

[0050] As an embodiment of the present invention, the particle size of the lime may be less than 150 μm, and more than 75% of the particle size of the lime may be less than 63 μm.

[0051] The addition of lime in the present invention can make the calcium in the lime react with the titanium in the bauxite to generate perovskite, avoid the titanium mineral wrapping the diaspore-type bauxite so that the alumina can hardly be dissolved, reduce the blocking effect of titanium on the dissolution of alumina, increase the contact between the mineral particles in the slurry and the alkaline solution, and thus enhance the dissolution effect of alumina.

[0052] As an embodiment of the present invention, the mass ratio of the alkaline solution to the bauxite is 2.4-4.8:1, and the solid content of the raw ore slurry is 250-350 g / L.

[0053] As an embodiment of the present invention, after multiple cycles, the alkaline solution added is an alkaline circulating mother liquor; the alkaline circulating mother liquor includes the newly added alkaline solution and the slurry intercepted by the filtering device and flowing back; the alkaline circulating mother liquor components may include caustic soda and alumina.

[0054] As an embodiment of the present invention, the composition of the alkaline circulating mother solution includes: 150-260 g / L of Na 2 O k and 80~160g / L Al 2 O 3 ; Among them, Na 2 O k It refers to caustic soda, i.e. sodium hydroxide; the ratio of the alkaline circulating mother liquor component is such that the molar ratio of sodium oxide to aluminum oxide in the sodium aluminate solution after dissolution is 1.38-1.45:1.

[0055] As an embodiment of the present invention, the temperature of the slurry in the reaction tank may be 50-500°C, further may be 200-300°C, specifically may be 265°C.

[0056] As an embodiment of the present invention, the pH value of the slurry may be 8 to 14, and the working pressure of the pump 22 may be 1000 to 10000 psi.

[0057] As an embodiment of the present invention, the ultrasonic power density of the first ultrasonic enhanced dissolution can be 0.1 to 1500 KW / m 3 The ultrasonic frequency is 20 to 2000 KHz. The present invention has no special limitation on the time of the first ultrasonic treatment.

[0058] In the present invention, the first ultrasonically enhanced slurry enters the ultrasonically enhanced pipeline 5 through the first discharge port 3 and the first spiral tube 4, and performs a second ultrasonically enhanced dissolution in the ultrasonically enhanced pipeline 5 to obtain a second ultrasonically enhanced slurry.

[0059] As an embodiment of the present invention, the ultrasonic power density of the second ultrasonic enhanced dissolution can be 0.1 to 1500 KW / m 3 The ultrasonic frequency is 20 to 2000 KHz. The present invention has no special limitation on the time of the second ultrasonic treatment.

[0060] When ultrasound acts on a solution, under the action of sufficiently strong ultrasound sound intensity, the so-called ultrasonic "cavitation effect" is produced, that is, the bubbles in the solution medium undergo formation, growth, expansion and explosion. Especially when the bubbles explode, a high temperature of more than 5000K and a temperature of about 5×10 7 Pa high pressure, accompanied by a strong shock wave, the slurry forms turbulence under the action of ultrasound, which reduces diffusion resistance, destroys the boundary layer, accelerates mass transfer, and at the same time breaks the wrapping of the sodium titanate film, refines the mineral particle size, and allows the alkali solution and alumina to fully react.

[0061] In the present invention, the second ultrasonic enhanced slurry enters the filtering device 8 through the No. 2 spiral tube 6 and the second feed port 7 for filtration to obtain a filter cake and a filtrate, respectively; the filtrate enters the second dissolution chamber 9 for a third ultrasonic enhanced dissolution; the filter cake enters the first dissolution chamber 2 for the first ultrasonic enhanced dissolution.

[0062] As an embodiment of the present invention, when the second ultrasonic enhanced slurry flows into the filter device 8, the filtrate in the slurry with a particle size smaller than the pore size of the filter cloth 21 passes through the filter device 8 and enters the second dissolution chamber 9; particles with a particle size larger than the pore size of the filter cloth 21 are retained and flow back to the first dissolution chamber 2 with part of the slurry, and continue the first ultrasonic enhanced dissolution as an alkaline circulating mother liquid.

[0063] As an embodiment of the present invention, the ultrasonic power density of the third ultrasonic enhancement can be 0.1 to 1500 KW / m 3 The ultrasonic frequency is 20 to 2000 KHz. The present invention has no special limitation on the time of the third ultrasonic treatment.

[0064] As an embodiment of the present invention, the filtrate after three ultrasonic enhanced dissolutions flows out from the second discharge port 12 to proceed to the next production process or flow into the next-level device.

[0065] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0066] Embodiment 1:

[0067] The bauxite used in the present invention is high-titanium bauxite, which is a diaspore-type bauxite with a high titanium content. The mineral components in the high-titanium ore include: 40.28% Al2 O 3 7.07% SiO 2 、33.68%Fe 2 O 3 5.15%TiO 2 , 0.48% CaO. The mass percentage of each mineral component in the high-titanium ore and the Al content in the dissolved slag 2 O 3 With SiO 2 The results of the mass ratios are shown in Table 1.

[0068] Table 1: Mass percentage of each mineral component in high titanium ore and Al 2 O 3 With SiO 2 The mass ratio (A / S (矿石) )

[0069]

[0070] Example 2

[0071] The lime components used in the present invention include: 92.2% CaO, 88.4% CaO f The components of the alkaline circulating mother liquor include: 220.34 g / L caustic soda and 120.58 g / L Al 2 O 3 .

[0072] 50 g of high titanium ore, 4.3 g of lime and 140 mL of alkaline circulating mother liquor in Example 1 were mixed to prepare raw ore slurry, and the raw ore slurry was added to the alumina dissolution device in the enhanced bauxite provided by the present invention, and ultrasonic enhanced dissolution was performed for 60 min. The temperature of ultrasonic enhanced dissolution was 265 ° C. and the power density of ultrasonic enhanced dissolution was 1260 KW / m 3 , the ultrasonic frequency is 20KHz, and at this time, the pressure in the device is 4.4MPa. The ultrasonically enhanced dissolution slag is tested, and the mass percentage of each mineral component in the dissolution slag after ultrasonically enhanced dissolution in Example 2 is recorded; and the relative dissolution rate of alumina in the high-titanium ore in Example 2 is calculated to be 97.87%.

[0073] Example 3

[0074] The conditions are basically the same as those in Example 2, except that the mass of lime in Example 2 is changed to 3.5 g. The ultrasonically enhanced slag is tested, and the mass percentage of each mineral component in the slag after ultrasonically enhanced slag in Example 3 is recorded; and the relative dissolution rate of alumina in the high titanium ore in Example 3 is calculated to be 95.95%.

[0075] Example 4

[0076] The conditions are basically the same as those in Example 2, except that the mass of lime in Example 2 is changed to 2.8 g. The ultrasonically enhanced slag is tested, and the mass percentage of each mineral component in the slag after ultrasonically enhanced slag in Example 4 is recorded; and the relative dissolution rate of alumina in the high-titanium ore in Example 4 is calculated to be 93.39%.

[0077] Comparative Example 1

[0078] The conditions are basically the same as those in Example 2, except that the original ore pulp is not subjected to ultrasound, and the dissolution is only carried out for 60 minutes in the dissolution device at a temperature of 265°C and a pressure of 4.4 MPa. The mass percentage of each mineral component in the dissolution slag after dissolution of Comparative Example 1 is recorded; and the relative dissolution rate of alumina of the high-titanium ore in Comparative Example 1 is calculated to be 88.91%.

[0079] Comparative Example 2

[0080] The conditions are basically the same as those in Example 3, except that the original ore pulp is not subjected to ultrasound, and the dissolution is only carried out in the dissolution device at a temperature of 265°C and a pressure of 4.4 MPa for 60 minutes. The mass percentage of each mineral component in the dissolution slag after dissolution in Comparative Example 2 is recorded; and the relative dissolution rate of alumina in the high-titanium ore in Comparative Example 2 is calculated to be 85.07%.

[0081] Table 2 shows the mass percentage of each mineral component in the leached slag obtained in Examples 2 to 4 and Comparative Examples 1 to 2, Al 2 O 3 With SiO 2 The relative dissolution rate of aluminum oxide = actual dissolution rate / theoretical dissolution rate, that is, the relative dissolution rate of aluminum oxide = (A / S (矿石) -A / S (溶出渣) )÷(A / S (矿石) -1).

[0082] Table 2: Content of each mineral in the leached slag of Examples 2 to 4 and Comparative Examples 1 to 2, Al 2 O 3 With SiO 2 The mass ratio (A / S (溶出渣) ) and the relative dissolution rate of alumina

[0083]

[0084] By comparing Example 2 and Comparative Example 1 or Example 3 and Comparative Example 2 in Table 2, it can be seen that, under the same other conditions, the relative dissolution rate of alumina using the ultrasonic enhancement method is higher than the relative dissolution rate of alumina not using the ultrasonic enhancement method, indicating that ultrasonic enhancement can effectively increase the relative dissolution rate of alumina in high-titanium ore.

[0085] By comparing the mass ratio and relative dissolution rate of alumina between Example 4 and Comparative Example 1, it can be seen that under ultrasonic conditions, the relative dissolution rate of alumina with the lime content reduced to 2.8 g is still higher than the relative dissolution rate of alumina with a lime content of 4.3 g added without ultrasonic enhancement, further illustrating that ultrasonic enhancement can effectively improve the dissolution effect of alumina in high-titanium ore.

[0086] Test Example 1

[0087] The slag after dissolution of Example 2 and Comparative Example 1 was subjected to diffraction analysis, and the results are shown in Table 3.

[0088] Table 3: Diffraction analysis of dissolved slag

[0089] condition Cancrinite Hydrated garnet Hematite Goethite Perovskite Chlorite Comparative Example 1 15.1 25.3 45.6 0.6 7.4 6.0 Example 2 13.0 21.7 46.1 0.3 12.4 6.5

[0090] From the diffraction analysis data, it can be seen that the cancrinite and hydrated garnet in the ultrasonically enhanced dissolution slag in Example 2 are lower than those in Comparative Example 1, and the perovskite content is significantly increased, indicating that ultrasound can enhance the effect of lime, make titanium and calcium react more completely, generate perovskite, reduce the retardation of titanium on the dissolution of alumina, and play a role in strengthening the dissolution of alumina. The XRD test results are consistent with the ultrasonic effect results analyzed above.

[0091] Test Example 2

[0092] The particle size and surface area of ​​the slag after dissolution in Example 2 and Comparative Example 1 were analyzed. The results were as follows: the D50 of the slag in Comparative Example 1 was 2.25 μm, and the specific surface area was 26.98 m 2 / g; Example 2 leaching slag D50 is 1.82μm, specific surface area is 47.93m 2 / g. The above results show that the slag under ultrasound has finer particle size and larger specific surface area, which means that ultrasound continuously washes the minerals, produces a stripping effect, reduces the size of the minerals, increases the contact between the minerals and the solution, and achieves the effect of strengthening the dissolution of alumina. The physical property test results of the slag are consistent with the results of ultrasonic action analyzed above.

[0093] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, these modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A device for strengthening the dissolution of aluminum oxide in bauxite, comprising at least one reaction unit, each of the reaction units independently comprising a reaction tank, a first spiral tube (4), an ultrasonic strengthening pipeline (5), a pump (22), a second spiral tube (6), a filtering device (8), a first ultrasonic system (10) and a second ultrasonic system (11); The reaction tank is divided into a first dissolution chamber (2) and a second dissolution chamber (9); the first dissolution chamber (2) and the second dissolution chamber (9) are connected at the top; the first ultrasonic system (10) is arranged between the first dissolution chamber (2) and the second dissolution chamber (9), and the second ultrasonic system (11) is arranged at the bottom of the ultrasonic enhancement pipeline (5); The first dissolution chamber (2) is provided with a first discharge port (3), and the second dissolution chamber (9) is provided with a second feed port (7); the first discharge port (3), a No. 1 spiral tube (4), an ultrasonic enhanced pipeline (5), a No. 2 spiral tube (6) and the second feed port (7) are connected in sequence; the second dissolution chamber (9) is provided with the filtering device (8); the filtering device (8) is connected to the second feed port (7); the pump (22) is provided at the connection between the ultrasonic enhanced pipeline (5) and the No. 2 spiral tube (6).

2. The device for strengthening the dissolution of alumina in bauxite according to claim 1, characterized in that: The first ultrasonic system (10) and the second ultrasonic system (11) independently comprise a shell (16), a plurality of piezoelectric ceramic vibrators (14), a plurality of amplitude transformers (13) and a plurality of ultrasonic probes (15); the shell (16) is a double-layer sleeve structure, comprising an outer sleeve and an inner sleeve sleeved inside the outer sleeve, the central axes of the inner sleeve and the outer sleeve coincide, and an ultrasonic cavity (17) is formed between the inner sleeve and the outer sleeve; the plurality of piezoelectric ceramic vibrators (14), the plurality of amplitude transformers (13) and the plurality of ultrasonic probes (15) are arranged in the ultrasonic cavity (17).

3. The device for strengthening the dissolution of alumina in bauxite according to claim 2, characterized in that: The amplitude transformer (13) is arranged on the outer surface of the inner cylinder of the shell (16), the piezoelectric ceramic vibrator (14) is arranged on the amplitude transformer (13), the ultrasonic probe (15) is arranged on the piezoelectric ceramic vibrator (14), and the ultrasonic probe (15) is connected to the inner surface of the outer cylinder of the shell (16).

4. The device for strengthening the dissolution of aluminum oxide in bauxite according to claim 1, characterized in that: The filtering device (8) comprises a filter plate (20) and a filter cloth (21) which are stacked together. The material of the filter plate (20) comprises a high-strength wear-resistant composite material, which comprises polypropylene, a diaphragm or rubber. The material of the filter cloth (21) comprises synthetic fibers, which comprises polyester, polypropylene, nylon or vinylon. The pore size of the filter cloth (21) is less than 100 μm.

5. The device for strengthening the dissolution of alumina in bauxite according to claim 1, characterized in that: The No. 1 spiral tube (4) and the No. 2 spiral tube (6) independently include a solid cylinder, a spiral blade channel (19) arranged around the solid cylinder, and an outer wall of the spiral tube; the outer side of the spiral blade channel (19) is connected to the inner surface of the outer wall of the spiral tube, and the inner side of the spiral blade channel (19) is connected to the outer surface of the solid cylinder; the space formed between the solid cylinder, the spiral blade channel (19) and the outer wall of the spiral tube is a slurry flow space (18), and the pitch is 5 dm to 1 m.

6. The device for strengthening the dissolution of aluminum oxide in bauxite according to claim 1, characterized in that: When there are multiple reaction units, the multiple reaction units are arranged in series; the first dissolution chamber (2) is provided with a first feed inlet (1), and the second dissolution chamber (9) is provided with a second discharge port (12); the multiple reaction units are connected in series in such a way that the second discharge port (12) of the first reaction unit is connected to the first feed inlet (1) of the next reaction unit.

7. A method for dissolving alumina in fortified bauxite using the device according to any one of claims 1 to 6, comprising the following steps: Mixing bauxite, lime and alkaline solution to obtain raw ore slurry, placing the raw ore slurry in the first dissolution chamber (2) for a first ultrasonic enhanced dissolution to obtain a first ultrasonic enhanced slurry; The first ultrasonic enhanced slurry enters the ultrasonic enhanced pipeline (5) through the first discharge port (3) and the first spiral tube (4), and performs a second ultrasonic enhanced dissolution in the ultrasonic enhanced pipeline (5) to obtain a second ultrasonic enhanced slurry; The second ultrasonic strengthening slurry enters the filtering device (8) through the second spiral tube (6) and the second feed inlet (7) for filtration to obtain a filter cake and a filtrate respectively; The filtrate enters the second dissolution chamber (9) to undergo a third ultrasonic enhanced dissolution; and the filter cake enters the first dissolution chamber (2) to undergo the first ultrasonic enhanced dissolution again.

8. The method for strengthening the dissolution of aluminum oxide in bauxite according to claim 7, characterized in that: The ultrasonic power density of the first, second and third ultrasonic enhanced dissolution is independently 0.1-1500 KW / m 3 , the ultrasonic frequency is 20~2000KHz.

9. The method for strengthening the dissolution of aluminum oxide in bauxite according to claim 7, characterized in that: The temperature of the slurry in the reaction tank is 50-500° C., the pH value of the slurry is 8-14, and the working pressure of the pump (22) is 1000-10000 psi.

10. The method for strengthening the dissolution of aluminum oxide in bauxite according to claim 7, characterized in that: The bauxite includes high-titanium bauxite, in which the mass of titanium dioxide is 3-7%; the amount of lime added is 6-12wt% of the bauxite; the mass ratio of the alkaline solution to the bauxite is 2.4-4.8:1, and the solid content of the original ore slurry is 250-350g / L.

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