A system for deep salt removal of sodium aluminate solution

Abstract

The utility model discloses a system for deep salt removal of sodium aluminate solution, wherein the feed ends of the sedimentation tank and the salt mixing tank are respectively connected with a forced effect salt removal device and an alkali salt removal device of the mixed salt removal, the forced effect salt removal device comprises a separation chamber, an exhaust steam discharge pipe, a heating chamber which circulates with the separation chamber, a forced effect feed pipe and a forced effect discharge pipe are arranged on the separation chamber, the forced effect discharge pipe is connected with a heat exchange device, a coil connected with the forced effect feed pipe is arranged in the heat exchange device, the coil is connected with the forced effect feed pipe, a forced effect discharge pipe is arranged on the heat exchange device, and the forced effect discharge pipe is connected with the sedimentation tank; the utility model can carry out deep salt removal, and solve the problem that carbon accumulation in the system causes carbon alkali increase and affects the normal operation of the system.

Description

Technical Field

[0001] The utility model relates to a system for deep salt discharge of sodium aluminate solution, belonging to the technical field of alumina production. Background Art

[0002] In the Bayer process of producing alumina, the carbon content of the system increases due to the increase in carbon brought into the ore, which has a great impact on the production system. In order to reduce the carbon content of the system, the current production adopts the method of forced salt removal and alkali removal. However, as the ore grade gradually declines and the impurity carbon continues to increase, the existing forced salt removal and alkali removal cannot meet the high maintenance and reduce the carbon content of the system.

[0003] That is, there is a need for a method and system for removing salt from a sodium aluminate solution, which can perform deep salt removal and solve the problem of carbon accumulation in the system leading to increased carbon alkali and affecting the normal operation of the system. Utility Model Content

[0004] In view of this, the purpose of the utility model is to provide a system for deep salt removal of sodium aluminate solution, which can perform deep salt removal and solve the problem of carbon accumulation in the system, resulting in increased carbon alkali and affecting the normal operation of the system; it can overcome the shortcomings of the existing technology.

[0005] The purpose of this utility model is achieved through the following technical solutions:

[0006] The utility model discloses a system for deep salt discharge of sodium aluminate solution, which comprises a sedimentation tank, a salt mixing tank, a salt discharge filter device and a causticizing system which are connected in sequence. The overflow pipe of the sedimentation tank and the filtrate discharge pipe of the salt discharge filter device are both connected to a strong alkali liquid tank. The feed ends of the sedimentation tank and the salt mixing tank are respectively connected to a forced effect salt discharge device and an alkali salt discharge device for mixed salt discharge. The forced effect salt discharge device comprises a separation chamber, on which an exhaust steam discharge pipe, a heating chamber which circulates with the separation chamber, a forced effect feed pipe and a forced effect discharge pipe are arranged. The forced effect discharge pipe is connected to a heat exchange device, in which a coil connected to the forced effect feed pipe is arranged, the coil is connected to a forced effect feed pipe, a forced effect discharge pipe is arranged on the heat exchange device, and the forced effect discharge pipe is connected to the sedimentation tank.

[0007] As mentioned above, thermometers are provided on both the forced curing feed pipe and the forced curing discharge pipe.

[0008] As mentioned above, a circulation pump is provided in the pipeline between the heating chamber and the separation chamber, and a feed pump is provided on the forced-effect discharge pipe.

[0009] As mentioned above, flow meters are provided on the forced efflux feed pipe, the forced efflux discharge pipe, the pipe between the sedimentation tank and the salt mixing tank, the pipe between the salt mixing tank and the salt discharge filter device, and the pipe between the salt discharge filter device and the causticizing system.

[0010] Compared with the prior art, the beneficial effects of the utility model are:

[0011] 1. The utility model uses a high-temperature forced-effect discharge material with a temperature of about 115°C and a forced-effect feed material with a temperature of 80°C for heat exchange. On the one hand, the forced-effect feed material is heated after heat exchange, and the heated forced-effect feed material reduces steam consumption after entering the forced-effect, which is beneficial to reducing production costs and improving economic benefits. On the other hand, after the forced-effect discharge material is heat exchanged, the temperature drops, and the carbon alkali in the sodium aluminate solution will precipitate in the form of sodium carbonate, and then go to the salt removal filter device. The larger particle crystals are beneficial to reducing the blockage of the filter cloth of the salt removal filter device, which is more conducive to salt removal filtration, and can achieve a deep salt removal effect, thereby realizing the utilization of high-carbon bauxite.

[0012] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and will be apparent to those skilled in the art based on the following examination and research, or can be taught from the practice of the present invention to some extent. The objectives and other advantages of the present invention can be achieved and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below with reference to the accompanying drawings, in which:

[0014] Figure 1 It is a schematic diagram of the connection structure of the utility model.

[0015] Figure 2 It is the corresponding curve diagram of the forced effective discharge temperature and the corresponding carbon alkali.

[0016] Among them, the sedimentation tank 1; the salt mixing tank 2; the salt removal and filtering device 3; the causticizing system 4; the overflow pipe 5; the filtrate discharge pipe 6; the strong alkali liquid tank 7; the forced alkali removal device 8; the separation chamber 8-1; the exhaust steam discharge pipe 8-3; the heating chamber 8-4; the forced alkali feed pipe 8-5; the forced alkali discharge pipe 8-6; the heat exchange device 9; the coil 9-1; the forced alkali feed pipe 9-2; the forced alkali discharge pipe 9-3; the alkali removal device 10. DETAILED DESCRIPTION

[0017] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the preferred embodiments are only for illustrating the present invention, rather than for limiting the protection scope of the present invention.

[0018] like Figure 1As shown, the utility model discloses a method for deep salt removal of sodium aluminate solution. The method reduces the temperature of the forced effect discharge to precipitate more sodium carbonate crystals through heat exchange between the forced effect discharge and the forced effect feed, and at the same time increases the temperature of the forced effect feed to reduce the steam consumption of the forced effect system; increasing the precipitation amount of sodium carbonate crystals is beneficial to deep salt removal, so that the forced effect discharge with a high temperature of about 115°C and the forced effect feed with a temperature of 80°C are used for heat exchange. On the one hand, after the forced effect discharge is heat exchanged, the temperature drops, and the carbon alkali in the sodium aluminate solution will be precipitated in the form of sodium carbonate, thereby achieving a deep salt removal effect. On the other hand, the forced effect feed is heated after heat exchange, and the heated forced effect feed reduces the steam consumption after entering the forced effect; at the same time, the precipitation amount of sodium carbonate crystals is increased by cooling, and more sodium carbonate in the solution can be removed, thereby realizing the utilization of high-carbon bauxite. Moreover, the process is combined with passing the sodium carbonate slurry for strong effective salt removal into the sedimentation tank 1 for sedimentation separation, and the overflow clear liquid after sedimentation is directly transported to the strong alkali liquid tank 7, and the highly concentrated sodium carbonate slurry after sedimentation is passed into the salt mixing tank 2 together with the sodium carbonate slurry of the alkali salt removal device 10 through the underflow, and the sodium carbonate slurry mixed in the salt mixing tank 2 enters the salt removal filter device 3 for filtration and separation, the sodium carbonate solid matter filtered by the salt removal filter device 3 is dissolved in water and then enters the causticizing system 4, and the filtrate filtered by the salt removal filter device 3 is merged into the strong alkali liquid tank by gravity.

[0019] After the forced effect discharge and forced effect feed are heat exchanged, the forced effect discharge temperature increases from 115°C to 95°C; and the forced effect feed temperature is greater than 80°C after heat exchange. The forced effect discharge and forced effect feed temperature must be higher than 95°C after heat exchange, which is conducive to ensuring the sedimentation effect of the subsequent sedimentation tank 1.

[0020] The sodium aluminate solution deep salt removal system comprises a sedimentation tank 1, a salt mixing tank 2, a salt removal filter device 3 and a causticizing system 4 which are connected in sequence, an overflow pipe 5 of the sedimentation tank 1 and a filtrate discharge pipe 6 of the salt removal filter device 3 are both connected to a strong alkali liquid tank 7, and is characterized in that: the feed ends of the sedimentation tank 1 and the salt mixing tank 2 are respectively connected to a forced effective salt removal device 8 for mixed salt removal and a causticizing salt removal device 10, the forced effective salt removal device 8 comprises a separation chamber 8-1, in which a separation chamber 8- 1 is provided with an exhaust steam discharge pipe 8-3, a heating chamber 8-4 which circulates with the separation chamber 8-1, a forced efficiency feed pipe 8-5 and a forced efficiency discharge pipe 8-6, the forced efficiency discharge pipe 8-6 is connected to a heat exchange device 9, a coil 9-1 connected to the forced efficiency feed pipe 8-5 is provided in the heat exchange device 9, the coil 9-1 is connected to a forced efficiency feed pipe 9-2, a forced efficiency discharge pipe 9-3 is provided on the heat exchange device 9, and the forced efficiency discharge pipe 9-3 is connected to the sedimentation tank 1.

[0021] Furthermore, thermometers are provided on the forced thermal effect feed pipe 8-5 and the forced thermal effect discharge pipe 9-3, so that the temperature of the forced thermal effect discharge can be controlled by the thermometers to ensure that the temperature is higher than 95°C after heat exchange.

[0022] Furthermore, a circulation pump is provided on the pipeline between the heating chamber 8-4 and the separation chamber 8-1, and a material transfer pump is provided on the forced efficiencies discharge pipe 8-6, so that the material conveying effect can be ensured by the circulation pump. Furthermore, flow meters are provided on the forced efficiencies feed pipe 9-2, the forced efficiencies discharge pipe 9-3, the pipeline between the sedimentation tank 1 and the salt mixing tank 2, the pipeline between the salt mixing tank 2 and the salt discharge filter 3, and the pipeline between the salt discharge filter 3 and the causticizing system 4.

[0023] The relevant data of carbon alkali discharged at different temperatures under the same caustic soda are as follows.

[0024] Table 1: Strong effect discharge temperature and corresponding carbon alkali data

[0025] Experimental sequence Temperature ℃ Caustic soda (g / L) Carbon alkali (g / L) 1 115 305 25.4 2 110 305 23.8 3 105 305 22.4 4 100 305 21.8 5 95 305 21.2 6 90 305 21.0

[0026] The data show that lowering the forced-effect discharge temperature can reduce the carbon alkali in the solution and achieve a deep salt removal effect.

[0027] At the same time, the corresponding curve of the forced effect discharge temperature and the corresponding carbon alkali is as follows Figure 2 shown.

[0028] Economic Benefit Accounting

[0029] Enhanced salt removal: Feed 150m3 of material per group with strong efficiency operation 3 / h calculation, currently two groups of forced effects are in operation. By reducing the temperature from 115℃ to 95℃, 41.36t more sodium carbonate can be discharged every day.

[0030] By increasing the temperature and reducing the steam, the feed material exchanges heat with the discharge material, and the temperature rises by an average of 12°C, which can save 7 tons of new steam per hour and create an annual benefit of more than 6 million yuan.

[0031] The above is only a preferred embodiment of the utility model, and does not limit the confidentiality of the utility model in any form. Any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the utility model without departing from the technical solution of the utility model still falls within the scope of the technical solution of the utility model.

Claims

1. A system for deep salt removal of sodium aluminate solution, comprising a sedimentation tank (1), a salt mixing tank (2), a salt removal filter device (3) and a causticizing system (4) connected in sequence, wherein the overflow pipe (5) of the sedimentation tank (1) and the filtrate discharge pipe (6) of the salt removal filter device (3) are both connected to a strong alkali solution tank (7), characterized in that: The feed ends of the sedimentation tank (1) and the salt mixing tank (2) are respectively connected to a forced effect salt removal device (8) and an alkali salt removal device (10) for mixed salt removal. The forced effect salt removal device (8) comprises a separation chamber (8-1). The separation chamber (8-1) is provided with an exhaust steam discharge pipe (8-3), a heating chamber (8-4) that circulates with the separation chamber (8-1), a forced effect feed pipe (8-5) and a forced effect discharge pipe (8-6). The forced effect discharge pipe (8-6) is connected to a heat exchange device (9). A coil (9-1) connected to the forced effect feed pipe (8-5) is provided in the heat exchange device (9). The coil (9-1) is connected to a forced effect feed pipe (9-2). A forced effect discharge pipe (9-3) is provided on the heat exchange device (9). The forced effect discharge pipe (9-3) is connected to the sedimentation tank (1).

2. The system for deep salt removal of sodium aluminate solution according to claim 1, characterized in that: The forced curing feed pipe (8-5) and the forced curing discharge pipe (9-3) are both provided with thermometers.

3. The system for deep salt removal of sodium aluminate solution according to claim 1, characterized in that: A circulation pump is provided on the pipeline between the heating chamber (8-4) and the separation chamber (8-1), and a feed pump is provided on the forced-effect discharge pipe (8-6).

4. The system for deep salt removal of sodium aluminate solution according to claim 1, characterized in that: Flow meters are provided on the forced causticization feed pipe (9-2), the forced causticization discharge pipe (9-3), the pipe between the sedimentation tank (1) and the salt mixing tank (2), the pipe between the salt mixing tank (2) and the salt discharge filter device (3), and the pipe between the salt discharge filter device (3) and the causticization system (4).

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