Dissolution system for mixed bauxite

Abstract

The utility model provides a dissolving-out system for mixed bauxite, and relates to the field of aluminum oxide production. Comprising a dissolution wet grinding machine, the dissolution wet grinding machine is communicated with a mixed bauxite storage bin, a carbide slag storage bin and a channelized heater, the channelized heater is communicated with a stepped buffer heat preservation pipe, the stepped buffer heat preservation pipe is communicated with a flash evaporator, the flash evaporator is communicated with a dilution settling tank, and the dilution settling tank is communicated with a solid-liquid separation unit. And the flash evaporator is also communicated with the channelized heater. According to the utility model, the dissolution rate of aluminum oxide can be improved, the alkali consumption is reduced, and the loss of aluminum oxide and sodium oxide in the dissolution process is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of alumina production, especially a mixed bauxite dissolution system. BACKGROUND

[0002] Alumina production depends on bauxite, among which the demand for complex mixed bauxite is the largest. However, due to the complex mineral phase of such mixed bauxite, the research on the dissolution mechanism and behavior of each mineral is lacking. For a long time, the dissolution process of mixed bauxite has the problems of low alumina recovery rate, high production consumption, high alkali consumption, and high energy consumption, resulting in the current situation of difficult utilization and low utilization rate of mixed bauxite resources.

[0003] Currently, high-temperature Bayer method is mainly used to dissolve mixed bauxite. Due to the large difference in dissolution performance of various aluminum-containing mineral phases in mixed bauxite, the reaction behavior of silicon-containing minerals in the high-temperature dissolution process is different, and there is mutual inlaying and coating. Therefore, the reaction behavior under different dissolution reaction conditions is extremely complex, and problems such as low alumina dissolution rate, high alkali and energy consumption, and loss of alumina and sodium oxide are prone to occur. Moreover, the existing dissolution process requires long-time high-temperature reaction, which wastes energy. SUMMARY

[0004] In order to solve the technical problems existing in the prior art, the embodiments of the utility model provide a dissolution system for mixed bauxite. The technical solution is as follows:

[0005] A dissolution system for mixed bauxite, comprising a dissolution wet mill, the dissolution wet mill is respectively connected with a mixed bauxite storage bin, a calcium carbide slag storage bin and a pipe heater, the pipe heater is connected with a stepped buffer heat preservation pipe, the stepped buffer heat preservation pipe is connected with a flash evaporator, the flash evaporator is connected with a dilution settling tank, the dilution settling tank is connected with a solid-liquid separation unit, and the flash evaporator is also connected with a pipe heater.

[0006] Optionally, the mixed bauxite storage bin delivers bauxite to the dissolution wet mill, the calcium carbide slag storage bin delivers calcium carbide slag to the dissolution wet mill, and the ratio of bauxite entering the dissolution wet mill to calcium carbide slag entering the dissolution wet mill ranges from 1:0.01 to 1:0.1.

[0007] Optionally, the mixture of calcium carbide slag and bauxite is wet ground by the dissolution wet mill and then enters the pipe heater, the pipe heater heats the mixture, and the heating temperature is greater than 230℃.

[0008] Optionally, the mixture after heating enters the stepped buffer heat preservation tank for heat preservation, the mixture after heat preservation enters the flash evaporator for cooling, the steam generated by cooling is transported to the pipeline heater, and the ore pulp obtained after cooling enters the dilution settling tank for dilution.

[0009] Optionally, the ore pulp after dilution enters the solid-liquid separation unit for solid-liquid separation to obtain a sodium aluminate solution and a residue.

[0010] Optionally, the bottom of the dilution settling tank is inverted conical.

[0011] The technical scheme provided by the embodiment of the utility model has at least the following beneficial effects:

[0012] The utility model technical scheme breaks through the traditional technology high temperature long time (250-260 DEG C, 60min above) dissolution process condition and production mode, the scheme can realize the efficient dissolution of alumina in the complex mixed bauxite at 230-245 DEG C and less than 60min of dissolution time.

[0013] Compared with the alumina-silicon ratio of more than 1.3 of the red mud obtained by the low-temperature dissolution process in the prior art, the alumina dissolution rate is increased by more than 5%, and compared with the alumina-silicon ratio of more than 1.1 of the red mud obtained by the high-temperature dissolution process in the prior art, the alumina dissolution rate is increased by more than 2%; the sodium-silicon ratio of the red mud obtained by the dissolution technology of the scheme is 0.4-0.56, compared with the sodium-silicon ratio of more than 0.65 of the red mud obtained by the high-temperature dissolution process in the prior art, about 50kg / t-AO caustic alkali consumption can be saved under the same ore grade, the alkali content in the red mud is reduced, that is, the alkali consumption is reduced, the loss of alumina and sodium oxide is reduced, and the efficient dissolution of alumina at medium temperature in the scheme reduces the energy consumption and saves resources compared with the high-temperature long-time dissolution in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical scheme in the embodiments of the utility model, the drawings needed in the embodiment description will be briefly introduced, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained by those skilled in the art without creative labor.

[0015] Figure 1 A schematic diagram of a dissolution system of a mixed bauxite provided by the utility model.

[0016] Reference signs:

[0017] ①, mixed bauxite storage; ②, carbide slag storage; ③, leaching wet grinder; ④, pipeline heater; ⑤, stepped buffer insulation tank; ⑥, flash evaporator; ⑦, dilution settling tank; ⑧, solid-liquid separation unit. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the scope of protection of the present application.

[0019] Unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the usual meaning understood by those skilled in the art to which the present application belongs. The "first", "second" and similar words used in the present application do not represent any order, quantity or importance, but are only used to distinguish different components. Similarly, "one", "a" or "the" and similar words do not represent a quantity limit, but represent the existence of at least one. "Including" or "containing" and similar words mean that the elements or objects before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connected" or "connected" and similar words are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect.

[0020] It should be noted that "up", "down", "left", "right", "front", "back" and the like used in the present application are only used to represent the relative positional relationship, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0021] As Figure 1As shown, the embodiment provides a leaching system for mixed bauxite; the leaching system comprises a leaching wet grinder ③, the leaching wet grinder ③ is respectively connected with a mixed bauxite storage ①, a carbide slag storage ② and a pipeline heater ④, the pipeline heater ④ is connected with a stepped buffer insulation pipe ⑤, the stepped buffer insulation pipe ⑤ is connected with a flash evaporator ⑥, the flash evaporator ⑥ is connected with a dilution settling tank ⑦, the dilution settling tank ⑦ is connected with a solid-liquid separation unit ⑧, and the flash evaporator is also connected with the pipeline heater ④. Among them, the leaching wet grinder ③, the pipeline heater ④ and the flash evaporator ⑥ are prior art, the stepped buffer insulation pipe ⑤ is a stepped arrangement of insulation pipes, which is prior art. The solid-liquid separation unit ⑧ is any device with solid-liquid separation function, which is prior art and will not be described here.

[0022] The mixed bauxite storage ① delivers bauxite to the leaching wet grinder ③, and the carbide slag storage ② delivers carbide slag to the leaching wet grinder ③. The ratio of bauxite to carbide slag entering the leaching wet grinder ③ ranges from 1:0.01 to 1:0.1. The mixture of carbide slag and bauxite is wet ground by the leaching wet grinder ③ and then enters the pipeline heater ④. The pipeline heater ④ heats the mixture, and the heating temperature is greater than 230°C. The mixture is heated to above 230°C. The heated mixture enters the stepped buffer insulation tank ⑤ for insulation. The mixture slurry effectively blocks the leaching reaction of silicon minerals in the mixed bauxite in the stepped buffer insulation tank ⑤, avoiding further heating of the mixture slurry and reducing the pressure of subsequent flashing.

[0023] The mixture after insulation enters the flash evaporator ⑥ for self-evaporation cooling. The steam generated during the cooling process is transported to the pipeline heater ④ for continued preheating of the mixture slurry. The slurry obtained after pressure reduction and temperature reduction in the flash evaporator ⑥ enters the dilution settling tank ⑦ for dilution and settling. The slurry obtained after dilution and settling enters the solid-liquid separation unit ⑧ for solid-liquid separation to obtain sodium aluminate solution and residue, realizing efficient separation of aluminum-containing components in mixed bauxite. The bottom of the dilution settling tank ⑦ is inverted conical. The mixed bauxite in the mixed bauxite storage ① and the carbide slag in the carbide slag storage ② are accurately proportioned according to the content of titanium oxide minerals in the bauxite.

[0024] This scheme breaks through the traditional technology of high-temperature and long-time (250-260°C, more than 60 minutes) leaching process conditions and production methods. This scheme can realize efficient leaching of aluminum oxide in complex mixed bauxite at 230-245°C and leaching time less than 60 minutes. Through additive technology, solid waste carbide slag generated in the chemical industry is used as an additive to further improve the leaching rate of diaspore and modify the red mud, and reduce the production of alkali consumption.

[0025] The scheme adopts the middle-temperature rapid-additive Bayer process technology to produce digestion on mixed bauxite, and the obtained red mud has an aluminum-silicon ratio in the range of 0.92-1, compared with the aluminum-silicon ratio of more than 1.3 of the red mud obtained by the low-temperature digestion process in the prior art, the alumina digestion rate is increased by more than 5%, compared with the aluminum-silicon ratio of more than 1.1 of the red mud obtained by the high-temperature digestion process in the prior art, the alumina digestion rate is increased by more than 2%; the sodium-silicon ratio of the red mud obtained by the digestion technology of the scheme is 0.4-0.56, compared with the sodium-silicon ratio of more than 0.65 of the red mud obtained by the high-temperature digestion process in the prior art, about 50 kg / t-AO caustic alkali consumption can be saved under the condition of the same ore grade, the alkali content in the red mud is reduced, that is, the alkali consumption is reduced, the loss of alumina and sodium oxide is reduced, and the efficient digestion of alumina can be realized at the middle temperature in the scheme, compared with the high-temperature long-time digestion in the prior art, the energy consumption is reduced, and resources are saved.

[0026] The following points need to be explained:

[0027] (1) The drawings of the embodiments of the utility model only involve the structures involved in the embodiments of the utility model, and other structures can refer to the usual design.

[0028] (2) In order to be clear, the thickness of the layer or area is enlarged or reduced in the drawings for describing the embodiments of the utility model, that is, these drawings are not drawn according to the actual proportion. It can be understood that when an element such as a layer, a film, an area or a substrate is referred to as being located "on" or "under" another element, the element can be "directly" located "on" or "under" another element or there can be an intermediate element.

[0029] (3) In the case of no conflict, the embodiments of the utility model and the features in the embodiments can be combined with each other to obtain new embodiments.

[0030] The above is only a specific embodiment of the utility model, but the protection scope of the utility model is not limited thereto, and the protection scope of the utility model should be subject to the protection scope of the claims.

Claims

1. A hybrid bauxite digestion system characterized by, The device comprises a leaching wet grinder, which is connected with a mixed bauxite storage, a carbide slag storage and a pipeline heater respectively, the pipeline heater is connected with a stepped buffer insulation pipe, the stepped buffer insulation pipe is connected with a flash evaporator, the flash evaporator is connected with a dilution settling tank, the dilution settling tank is connected with a solid-liquid separation unit, and the flash evaporator is also connected with a pipeline heater.

2. The hybrid bauxite digestion system of claim 1, wherein, The mixed bauxite storage delivers bauxite to the leaching wet grinder, the carbide slag storage delivers carbide slag to the leaching wet grinder, and the ratio of bauxite to carbide slag entering the leaching wet grinder ranges from 1:0.01 to 1:0.

1.

3. The hybrid bauxite digestion system of claim 2, wherein, The mixture of carbide slag and bauxite enters the pipeline heater after wet grinding by the leaching wet grinder, the pipeline heater heats the mixture, and the heating temperature is greater than 230 DEG C.

4. The hybrid bauxite digestion system of claim 3, wherein, The heated mixture enters the stepped buffer insulation pipe for insulation, the insulated mixture enters the flash evaporator for cooling, the generated steam is transported to the pipeline heater, and the obtained slurry after cooling enters the dilution settling tank for dilution.

5. The hybrid bauxite digestion system of claim 4, wherein, The diluted slurry enters the solid-liquid separation unit for solid-liquid separation to obtain sodium aluminate solution and residue.

6. The hybrid bauxite digestion system of claim 4, wherein, The bottom of the dilution settling tank is inverted conical.

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