System for reducing carbon and alkali accumulation in process of producing aluminum oxide by Bayer process

Abstract

The utility model discloses a system for reducing carbon and alkali accumulation in a process of producing aluminum oxide by a Bayer process, which comprises a salt discharging machine, a salt settling tank and a salt settling tank, a filtrate outlet of the salt discharging machine is connected with a strong alkali tank through a first pipeline component, and an overflow port of the salt settling tank is connected with the strong alkali tank through a second pipeline component. The middle of the strong alkali tank in the depth direction is connected with the circulating mother liquor blending tank through a strong alkali liquor conveying pipeline assembly, the bottom of the strong alkali tank is connected with the salt settling tank through an underflow conveying pipeline assembly, and the bottom of the salt settling tank is connected with the salt discharging machine through a salt discharging pipeline assembly; strong alkali liquor in the middle of the depth direction of the strong alkali tank in the system is clear, and is conveyed to the circulating mother liquor blending tank through the strong alkali liquor conveying pipeline assembly to adjust the circulating mother liquor, so that sodium carbonate returned to the process of producing aluminum oxide through the Bayer process is obviously reduced, and the problems of high solid content and unsmooth alkali supplement caused by sodium carbonate are avoided; the concentration of circulating mother liquor meets the requirement.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of bayer process production of alumina, especially relate to a system for reducing carbon alkali accumulation in bayer process production of alumina. BACKGROUND

[0002] In the bayer process production of alumina, the strong lye is a high concentration alkali for adjusting qualified circulating mother liquor, which is mainly obtained by chemical alkali and forced evaporation concentration, and then filtered by a salt discharging machine to precipitate sodium carbonate solid, and part of it is obtained by overflow of a salt settling tank 2, as shown in the figure. Figure 2 The strong lye enters a strong lye tank 1 for adjusting circulating mother liquor.

[0003] In the strong lye tank 1, sodium carbonate will be precipitated again due to the cooling of the strong lye, and sodium carbonate will also be brought in by the turbid overflow of the salt settling tank 2, which will cause a large amount of sodium carbonate solid to accumulate at the bottom of the strong lye tank 1 after a period of operation, and during the adjustment of the circulating mother liquor, the strong lye is supplemented from the low position of the strong lye tank 1, and part of the sodium carbonate will enter the process again, which will cause the carbon alkali ratio of the circulating mother liquor to rise, affecting the normal operation of the production, and greatly reducing the salt discharging efficiency; in addition, with the continuous accumulation of sodium carbonate at the bottom of the strong lye tank 1, the alkali supplement will be difficult, the concentration of the circulating mother liquor will not meet the production requirements, and the strong lye tank 1 has to be cleaned. CONTENT OF THE UTILITY MODEL

[0004] Therefore, the utility model aims to provide a system for reducing carbon alkali accumulation in the bayer process production of alumina to at least solve the technical problems mentioned in the background.

[0005] The utility model aims to realize the following technical scheme:

[0006] A system for reducing carbon alkali accumulation in the bayer process production of alumina, which comprises a salt discharging machine, a filtrate outlet of the salt discharging machine is connected to a strong lye tank through a first pipe line assembly, it further comprises a salt settling tank, an overflow port of the salt settling tank is connected to the strong lye tank through a second pipe line assembly, a middle part of the strong lye tank in the depth direction is connected to a circulating mother liquor adjusting tank through a strong lye conveying pipe line assembly, the bottom of the strong lye tank is connected to the salt settling tank through a bottom flow conveying pipe line assembly, and the bottom of the salt settling tank is connected to the salt discharging machine through a salt discharging pipe line assembly.

[0007] Further, the strong lye conveying pipe line assembly comprises a strong lye conveying pipe and a pump and a valve arranged on the strong lye conveying pipe.

[0008] Still further, the bottom flow conveying pipe line assembly comprises a bottom flow conveying pipe and a pump and a valve arranged on the bottom flow conveying pipe.

[0009] Still further, the salt discharging pipe line assembly comprises a salt discharging pipe and a pump and a valve arranged on the salt discharging pipe. Still further, the salt discharging pipe line assembly comprises a salt discharging pipe and a pump and a valve arranged on the salt discharging pipe.

[0010] The utility model discloses the beneficial effect is:

[0011] The utility model discloses a system of reducing carbon alkali accumulation in bayer method production alumina process, the strong lye in the depth direction middle part of strong alkali tank is relatively clear, contains very little sodium carbonate, is transported to the circulation mother liquor deployment tank for adjusting circulation mother liquor through strong lye delivery pipeline subassembly, makes the sodium carbonate that returns to bayer method production alumina process significantly reduce, and the problem that the solid content is high because of sodium carbonate, and alkali is not smooth, and the circulation mother liquor concentration reaches the requirement. Sodium carbonate precipitates in the tank bottom in the strong alkali tank, is transported to the salt settlement tank and carries out the salt discharge through the underflow delivery pipeline subassembly, and the sodium carbonate of less alkali turns back, improves the salt discharge efficiency, improves the operation cycle of strong alkali tank.

[0012] The other advantages, objects and features of the utility model will be described in the subsequent specification to some extent, and to some extent, it will be obvious to those skilled in the art based on the study of the following text or can be taught from the practice of the utility model. The objects and other advantages of the utility model can be realized and obtained by the following specification. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to make the purpose, technical scheme and advantages of the utility model more clear, the utility model will be further described in detail below combined with the drawings, wherein:

[0014] Figure 1 The schematic diagram of the present application.

[0015] Figure 2 The schematic diagram of prior art.

[0016] In the drawing: 1. strong alkali tank, 2. salt settlement tank, 3. pump. DETAILED DESCRIPTION

[0017] The preferred embodiments of the utility model will be described in detail below with reference to the drawings. It should be understood that the preferred embodiments are only for illustrating the utility model, and not for limiting the protection scope of the utility model.

[0018] Example one

[0019] As Figure 1As shown, a system for reducing carbon alkali accumulation in a Bayer process for producing alumina, which comprises a salt discharging machine, a filtrate outlet of the salt discharging machine is connected to a strong alkali tank through a first pipeline assembly, the first pipeline assembly comprises a first pipeline and a valve arranged on the first pipeline, and the system further comprises a salt settling tank, an overflow port of the salt settling tank is connected to the strong alkali tank through a second pipeline assembly, the second pipeline assembly comprises a second pipeline and a valve arranged on the second pipeline, a middle part in a depth direction of the strong alkali tank is connected to a circulating mother liquor adjusting tank through a strong alkali liquor conveying pipeline assembly, the strong alkali liquor conveying pipeline assembly comprises a strong alkali liquor conveying pipe and a pump and a valve arranged on the strong alkali liquor conveying pipe, a bottom of the strong alkali tank is connected to the salt settling tank through a underflow conveying pipeline assembly, the underflow conveying pipeline assembly comprises an underflow conveying pipe and a pump and a valve arranged on the underflow conveying pipe, and a bottom of the salt settling tank is connected to the salt discharging machine through a salt discharging pipeline assembly, the salt discharging pipeline assembly comprises a salt discharging pipe and a pump and a valve arranged on the salt discharging pipe.

[0020] In the above embodiment, the strong alkali liquor in the middle part in the depth direction of the strong alkali tank is relatively clear, and contains very little sodium carbonate, which is conveyed to the circulating mother liquor adjusting tank through the strong alkali liquor conveying pipeline assembly to adjust the circulating mother liquor, so that the sodium carbonate returned to the Bayer process for producing alumina is significantly reduced, and the problems of high solid content and poor alkali supplement caused by sodium carbonate do not occur, and the concentration of the circulating mother liquor reaches the requirement. The sodium carbonate in the strong alkali tank is precipitated at the bottom of the tank, the pump and the valve on the underflow conveying pipe are opened to send the sodium carbonate at the bottom of the tank to the salt settling tank for settling, and then the pump and the valve on the salt discharging pipe are opened to send the slurry at the bottom of the settling tank to the salt discharging machine for filtration to remove the sodium carbonate solid. The use of the above embodiment significantly prolongs the operation cycle of the strong alkali tank, the sodium carbonate in the alkali is reduced, and the salt discharging efficiency is improved.

[0021] After the above embodiment is implemented, the operation cycle of the strong alkali tank 1 is prolonged from original cleaning twice a year to cleaning once a year (two existing strong alkali tanks 2, and cleaning cost of 85,000 yuan per year can be saved).

[0022] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the purpose and scope of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A system for reducing carbon and alkali accumulation in the Bayer process for alumina production, characterized in that: It includes a salt discharge machine, the filtrate outlet of which is connected to a strong alkali tank via a first pipeline assembly. It also includes a salt settling tank, the overflow port of which is connected to the strong alkali tank via a second pipeline assembly. The middle of the strong alkali tank in the depth direction is connected to a circulating mother liquor mixing tank via a strong alkali liquid conveying pipeline assembly. The bottom of the strong alkali tank is connected to the salt settling tank via an underflow conveying pipeline assembly. The bottom of the salt settling tank is connected to the salt discharge machine via a salt discharge pipeline assembly.

2. The system for reducing carbon and alkali accumulation in the Bayer process for alumina production according to claim 1, characterized in that: The strong alkali solution delivery pipeline assembly includes a strong alkali solution delivery pipe and a pump and valve installed on the strong alkali solution delivery pipe.

3. The system for reducing carbon and alkali accumulation in the Bayer process for alumina production according to claim 1 or 2, characterized in that: The underflow delivery pipeline assembly includes an underflow delivery pipe and a pump and valve installed on the underflow delivery pipe.

4. The system for reducing carbon and alkali accumulation in the Bayer process for alumina production according to claim 1, characterized in that: The salt discharge pipeline assembly includes a salt discharge pipe and a pump and valve installed on the salt discharge pipe.

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