Rapid red mud separating and washing unit device

Abstract

The utility model discloses a rapid red mud separating and washing unit device, belongs to the technical field of aluminum oxide production, and particularly relates to a rapid red mud separating and washing process and device in Bayer process red mud comprehensive utilization. Specifically, a tilting-pan vacuum filter is adopted as a main machine to realize rapid separation and washing of dissolved slurry during comprehensive utilization of Bayer process red mud, filter partitions and corollary equipment are optimized according to process steps to form a unit device, rapid separation and secondary washing are completed, secondary reaction loss is avoided, and the production efficiency is improved. Compared with a traditional settling tank device, the dissolution rate of aluminum oxide and sodium oxide is increased by 2-3%, the washing water amount per ton of dry red mud is reduced to be smaller than or equal to 2 t from 4-5 t, unit operation is simplified, and economic benefits are improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of alumina production, in particular to a red mud rapid separation and washing process and device in the comprehensive utilization of red mud by the Bayer process. Background Art

[0002] At present, domestic alumina production basically adopts the Bayer process. The industrial solid waste discharged during the production process is red mud with strong alkalinity. Every ton of alumina produced will produce 1.2 to 1.4 tons of red mud. With the increase in the demand for alumina and the decrease in the grade of bauxite, the discharge of red mud is getting larger and larger. The stacking of red mud not only occupies a large amount of land, soil alkalization, and groundwater pollution, but also causes secondary waste of resources such as aluminum oxide and sodium oxide in the red mud. With the improvement of environmental protection requirements, the comprehensive utilization of red mud recycling resources is imminent. At present, the most basic, recyclable, easy to implement and economically valuable components in red mud are caustic soda and aluminum oxide. After recovering caustic soda and aluminum oxide, the components of red mud discharged are basically close to water. The components of red mud can be directly used as raw materials in the cement industry; a relatively mature recovery process is to use sintering to extract alumina and recover caustic soda, but the traditional sintering method uses a group of sedimentation tanks for separation and washing after the clinker is dissolved, which results in secondary reaction losses of caustic soda and alumina, a large amount of water for washing per ton of red mud, and an increase in silica content; during operation, the sedimentation tank is easily clogged, the start-up rate is reduced, and production capacity is seriously affected. The same problem will be encountered when using the sintering process for the comprehensive utilization of Bayer red mud. The washed red mud usually needs further dehydration treatment. How to achieve the comprehensive utilization of Bayer red mud in the separation and washing sections to reduce losses, improve recovery rates, ensure continuous and stable production, and improve economic benefits is a problem that needs to be solved. Summary of the Invention

[0003] In order to solve the problems existing in the prior art, the utility model provides a red mud rapid separation and washing unit device, which adopts a tilting vacuum filter as the main machine to realize the rapid separation and washing of the dissolved slurry during the comprehensive utilization of Bayer red mud. The filter partitioning and supporting equipment are optimized according to the process steps to form a unit device, complete rapid separation and secondary washing, and avoid secondary reaction losses. Compared with the traditional group sedimentation tank device, the dissolution rate of aluminum oxide and sodium oxide is increased by 2-3%, and the washing water volume per ton of dry red mud is reduced from 4-5t to ≤2t, which simplifies the unit operation and improves the economic benefits.

[0004] The technical solution adopted by the utility model to solve its technical problems is: a red mud rapid separation and washing unit device, which consists of a tilting disc vacuum filter, an integrated gas-liquid separator, a suction gas-liquid separator, a gas collecting hood, a slag bucket, a slurry pump, a return liquid pump, a washing liquid pump, a slurry tank, a return liquid tank, a washing liquid tank and an agitator; the main unit of the unit device is a tilting disc vacuum filter (hereinafter referred to as the filter), an integrated gas-liquid separator is installed on the distribution valve of the filter, and the vacuum power reaches the filtering surface directly. The unit device adopts a vacuum pipe inserted into the liquid water seal and adopts an atmospheric leg drainage method in which the liquid column height is balanced with the vacuum, without vacuum drainage equipment. Compared with the original configuration of multiple gas-liquid separator groups or ring pipe gas-liquid separators with different concentrations under the filter, the integrated gas-liquid separator reduces vacuum power loss and also reduces the installation height of the filter (that is, reduces the height of the plant); the plant layout of the unit device is as follows: :An air collecting hood is installed above the filter, the filter is installed on the third floor, the slag hopper is installed under the third floor, the suction gas-liquid separator is installed on the second floor, and the remaining pumps and tanks are installed on the first floor. The slurry tank is equipped with a stirrer, and the outlet of each tank is connected to the pump; the filter process is divided into: a 360° filtration area → a washing area → a second washing + suction area → a backwashing unloading area → a filter cloth washing area → a filter cloth suction area, the filtrate outlet pipes of the filtration area and the first washing area are inserted below the liquid level of the return liquid tank, the filtrate outlet pipes of the second washing + suction area are inserted below the liquid level of the washing liquid tank, the pipes of the filter cloth suction area are connected to the inlet of the suction gas-liquid separator, and the pipes of the lower liquid outlet of the suction gas-liquid separator are inserted below the liquid level of the slurry tank; the purpose of setting the filter cloth suction area in front of the filtration area is to reduce the residual water from the filter cloth washing from entering the red mud slurry dilution recovery liquid, and the upper air outlet of the suction gas-liquid separator is opened or closed to extract vacuum air according to the process indicators.

[0005] When the unit is in operation, the red mud slurry (temperature 80-90℃, solid content 200-400g / L) flows through the unit as follows: entering the filter area of ​​the filter for rapid separation, the gas phase is collected by the gas collecting hood and discharged as tail gas, the liquid phase passes through the filter cloth and enters the return liquid tank, and together with the liquid phase discharged from the first washing area, forms the recovered liquid, which is pumped by the return liquid pump to the Bayer process alumina production process, and the solid phase is retained on the filter cloth of the filter → solid phase (moisture content 40- 60%) enters the first washing area for washing → the solid phase (moisture content 40-60%) enters the second washing + drying area for washing and then drying → the solid phase (moisture content ≤38%) enters the backwash unloading area and is dumped into the slag bucket and falls into the slurry tank → the solid phase is evenly mixed with the filter cloth washing water to form slurry, and the slurry (solid content 200-400g / L) is pumped to the dehydration unit by the slurry pump; the washing water (temperature>50℃, ~0.8 times the weight of dry red mud) is washed in countercurrent, and in the single The process path on the unit device is as follows: it enters the secondary wash + drying area of ​​the filter, penetrates the filter cake for washing, enters the washing liquid tank and is then pumped out by the washing liquid pump → enters the primary wash area of ​​the filter, penetrates the filter cake for washing, enters the return liquid tank and forms a recovered liquid together with the liquid phase of the red mud slurry; part of the filter cloth washing water (temperature > 40°C, water consumption of the filter cloth washing nozzle of the filter) enters the filter cloth washing area of ​​the filter, falls into the slag hopper after washing the filter cloth surface, and then enters the slag trough. Part of the filter cloth washing water is added from the side wall of the slag hopper and then enters the slag trough to adjust the liquid-solid ratio of the slurry; compressed air enters the backwash unloading area of ​​the filter to assist in unloading and filter cloth regeneration; the main vacuum air is extracted from the outlet of the integrated gas-liquid separator to provide separation power for the filter; the auxiliary vacuum air is extracted from the upper outlet of the drying gas-liquid separator; the temperature, solid content and other parameters of each material during operation are controlled in order to achieve better economic benefits while maintaining continuous and stable operation of the unit device.

[0006] The utility model discloses a red mud rapid separation and washing unit device, which can complete the separation and secondary washing of the red mud slurry dissolved during the comprehensive utilization of Bayer red mud in sequence within a few minutes, consumes a total of 2t of washing water and filter cloth flushing water per ton of dry red mud, and increases the dissolution rate of aluminum oxide and sodium oxide by 2-3%, thereby improving economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The technical solution of the present utility model will be further described below with reference to the accompanying drawings and embodiments.

[0008] Figure 1 This is a schematic diagram of a red mud rapid separation and washing unit device;

[0009] In the figure, PSW0. red mud slurry, PSW. slurry, PW0. washing water, PW1. filter cloth washing water, PW. recovered liquid, PG. tail gas, CA. compressed air, VE1. main vacuum air, VE2. auxiliary vacuum air, I. filtration area, II. primary washing area, III. secondary washing + drying area, IV. backwashing unloading area, V. filter cloth washing area, VI. filter cloth drying area, F. tilting vacuum filter, E1. integrated gas-liquid separator, E2. drying gas-liquid separator, Z. gas collecting hood, D. slag hopper, P1. slurry pump, P2. return liquid pump, P3. washing liquid pump, V1. slurry tank, V2. return liquid tank, V3. washing liquid tank, A. agitator. DETAILED DESCRIPTION

[0010] A red mud rapid separation and washing unit device according to an embodiment comprises a tilting plate vacuum filter F, an integrated gas-liquid separator E1, a dry gas-liquid separator E2, a gas collection hood Z, a slag hopper D, a slurry pump P1, a return liquid pump P2, a washing liquid pump P3, a slurry tank V1, a return liquid tank V2, a washing liquid tank V3, and an agitator A. The gas collection hood Z is installed above the tilting plate vacuum filter F, the integrated gas-liquid separator E1 is installed on the distribution valve of the tilting plate vacuum filter F, the tilting plate vacuum filter F is installed on the third floor at a height of +10.00m, the slag hopper D is installed below the third floor, the dry gas-liquid separator E2 is installed on the second floor at a height of +6.00m, and the remaining equipment is installed on the ground at ±0.00m on the first floor. The slurry tank V1 is equipped with a stirrer A, and the outlets of each tank are connected to a pump. The process zones of the tilting disc vacuum filter F are as follows: 360° around, there are filtration zone I → primary washing zone II → secondary washing + drying zone III → backwashing unloading zone IV → filter cloth washing zone V → filter cloth drying zone VI. The filtrate outlet pipes of filtration zone I and primary washing zone II are inserted below the liquid level of the return liquid tank V2, the filtrate outlet pipe of secondary washing + drying zone III is inserted below the liquid level of the washing liquid tank V3, the pipe of the filter cloth drying zone VI is connected to the inlet of the drying gas-liquid separator E2, and the lower liquid outlet pipe of the drying gas-liquid separator E2 is inserted below the liquid level of the slurry tank V1. When the unit is in operation, the red mud slurry PSW0 (temperature 80-90°C, solid content 200-400g / L) enters the tilting disc vacuum filter. In the filter zone I of the disc vacuum filter F, the gas phase is collected by the gas collecting hood Z and discharged as tail gas PG, the liquid phase passes through the filter cloth and enters the return liquid tank V2, and together with the liquid phase discharged from the first washing zone II, forms the recovered liquid PW, which is pumped out by the return liquid pump P2. The solid phase is retained → the solid phase (moisture content 40-60%) enters the first washing zone II → the solid phase (moisture content 40-60%) enters the second washing + drying zone III → the solid phase (moisture content ≤38%) enters the backwash unloading zone IV, is dumped into the slag hopper D and falls into the slurry tank V1 → the solid phase and the filter cloth washing water PW1 are evenly mixed to form slurry PSW (solid content 200-400g / L) which is pumped out by the slurry pump P1; washing water PW0 (temperature > 50℃, ~0.8 times the weight of dry red mud) After entering the secondary washing + drying zone III, it enters the washing liquid tank V3 and is then pumped by the washing liquid pump P3 into the primary washing zone II before entering the return liquid tank V2 to form the recovered liquid PW together with the liquid phase of the red mud slurry PSW0. Part of the filter cloth washing water PW1 (temperature > 40°C, water consumption of the filter cloth washing nozzle of the tilting vacuum filter F) enters the filter cloth washing zone V and falls into the slag hopper D and then enters the slurry tank V1. Part of the filter cloth washing water PW1 is added from the side wall of the slag hopper D and then enters the slurry tank V1 to adjust the liquid-solid ratio of the slurry PSW. The compressed air CA enters the backwash unloading zone IV. The main vacuum air VE1 is extracted from the outlet of the integrated gas-liquid separator E1; the auxiliary vacuum air VE2 is extracted from the upper outlet of the drying gas-liquid separator E2.

[0011] The above description is only a specific embodiment of the present invention, but the implementation of the present invention is not limited thereto. Any changes or modifications made within the scope of the present invention are included in the patent scope of the present invention.

Claims

1. A red mud rapid separation and washing unit device, comprising a tilting disc vacuum filter (F), an integrated gas-liquid separator (E1), a suction gas-liquid separator (E2), a gas collecting hood (Z), a slag hopper (D), a slurry pump (P1), a return liquid pump (P2), a washing liquid pump (P3), a slurry tank (V1), a return liquid tank (V2), a washing liquid tank (V3), and an agitator (A); characterized in that The tiltable vacuum filter (F) is the main unit of the unit device, and is provided with a filtration area (I) → a first washing area (II) → a second washing + drying area (III) → a backwashing unloading area (IV) → a filter cloth washing area (V) → a filter cloth drying area (VI) in a 360° circle. A gas collecting hood (Z) is installed above the tiltable vacuum filter (F), and an integrated gas-liquid separator E1 is installed on the distribution valve on the tiltable vacuum filter (F). An atmospheric leg liquid discharge method is adopted in which the liquid column height and the vacuum are balanced. The tiltable vacuum filter (F) is installed on the third floor, the slag hopper (D) is installed below the third floor, the pump and the tank are installed on the ground of the first floor, and the drying gas-liquid separator (E2) is installed on the second floor. The upper air outlet of the drying gas-liquid separator (E2) opens or closes the auxiliary vacuum air (VE2) according to the process indicators.

2. The red mud rapid separation and washing unit device according to claim 1, characterized in that: When the unit is in operation, the temperature of the red mud slurry (PSW0) is controlled at 80-90°C, the solid content is controlled at 200-400 g / L, the solid phase enters the washing process when the moisture content is 40-60%, and the solid phase enters the backwash unloading area (IV) for dumping when the moisture content is ≤38%. The temperature of the washing water (PW0) is controlled at >50°C and countercurrent washing is adopted. The temperature of the filter cloth washing water (PW1) is controlled at >40°C.

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