CN118108384A

CN118108384A - Red mud dealkalization device and method

Info

Publication number: CN118108384A
Application number: CN202410260838.8A
Authority: CN
Inventors: 张雪松; 许世龙; 阴晓雪; 王伟; 孙锲
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2024-03-07
Filing date: 2024-03-07
Publication date: 2024-05-31

Abstract

The invention relates to a red mud dealkalization device and a method, and belongs to the technical field of red mud dealkalization. Red mud dealkalization device includes: the device comprises a base, a hollow cylindrical mixer, a feeding unit and a discharging unit; the mixer is arranged on the base and is divided into three parts from top to bottom: the stirring zone is connected with the feeding zone; the top end of the feeding area is provided with a red mud inlet, the side wall of the feeding area is provided with a plurality of water inlets, and the directions of the water inlets are arranged along the tangential direction of the side wall of the mixer, and are all left-handed or all right-handed; the inside of the stirring area is a straight cylinder with the same inner diameter up and down; a discharge hole is formed in the center of the bottom of the discharge area; a reflux plate is arranged above the discharging area in the mixer. In the invention, water enters the mixer to form a rotary flowing state, red mud powder is thrown into the rotary flowing water from the top of the container, and preliminary mixing is realized; the reflux plate forces alkali liquor to flow out from the periphery of the reflux plate, so that the red mud powder and water are fully mixed, and the mixing efficiency is improved. Because stirring blades are not adopted, repeated disassembly and assembly of the transmission device are avoided.

Description

Red mud dealkalization device and method

Technical Field

The invention belongs to the technical field of red mud dealkalization, and particularly relates to a red mud dealkalization device and method.

Background

The disclosure of this background section is only intended to increase the understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art.

Red mud, also known as bayer process red mud, is a strongly alkaline solid waste produced in alumina production. Comprises mineral components such as hematite, calcite, cancrinite, tricalcium aluminate, hydrated garnet, hydrated sodium aluminosilicate and the like. Because the red mud has small particle size and poor agglomeration, the red mud is easy to be weathered in an open-air stack yard to generate dust, and the environment is polluted. When the waste water is recycled, dealkalization treatment is needed. Common treatment methods include: there are water washing, acid leaching, lime leaching, salt leaching, etc.

The water washing method is the simplest physical dealkalization treatment method, and the water can directly leach out free alkali in the red mud, so that the content of sodium ions and other soluble salts in the red mud is reduced. The water washing method requires that water as a diluent is sufficiently contacted with red mud, and in order to increase the leaching rate, the red mud and water are mixed in a stirring tank. Because a large amount of mineral components exist in the red mud, the blades of the stirring device are severely worn, and the service life of equipment is greatly influenced; mineral components can accumulate in the insufficiently stirred position, causing blockage inside the equipment; frequent replacement of wear parts can also severely affect the treatment efficiency of red mud.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a red mud dealkalization device and a method, which are used for feeding materials in the tangential direction of a stirring device to generate a stirring effect without adopting a mechanical device for stirring red mud slurry, so that frequent replacement of stirring blades is avoided.

In order to achieve the above purpose, the technical scheme of the invention is as follows:

In a first aspect, a red mud dealkalization apparatus includes: the device comprises a base, a hollow cylindrical mixer, a feeding unit and a discharging unit;

The mixer is arranged on the base and is divided into three parts from top to bottom: the stirring zone is connected with the feeding zone; the top end of the feeding area is provided with a red mud inlet, the side wall of the feeding area is provided with a plurality of water inlets, and the directions of the water inlets are along the tangential direction of the side wall of the mixer, and are all in a left-handed direction or all in a right-handed direction; the inside of the stirring area is a straight cylinder with the same inner diameter up and down; a discharge hole is formed in the center of the bottom of the discharge area; a reflux plate is arranged above a discharging area in the mixer;

the feeding unit comprises a red mud input pipe and a water supply pipe; the red mud inlet of the red mud input pipe is communicated, and the water supply pipe is communicated with the water inlet;

the discharging unit comprises a discharging pipe, and the discharging pipe is communicated with the discharging hole.

In a second aspect, a red mud dealkalization method using the red mud dealkalization device includes the following steps:

s1, obtaining the red mud quantity required to be input and the water quantity used for dilution according to the red mud components and the pH value of target alkali liquor;

s2, inputting water into the mixer through the feeding unit according to the water quantity obtained in the S1, and inputting red mud into the mixer through the feeding unit according to the red mud quantity obtained in the S1 after the stirring area forms a rotary flow state;

S3, in the mixer, the red mud falls into the water flowing in a rotating way, is mixed and stirred to form alkali liquor, enters a discharge area at the outer side of the reflux plate, and flows out through a discharge hole;

And S4, adjusting the water delivery amount in the S2 and the red mud amount according to the pH value and the viscosity of the alkali liquor measured at the position of the discharge pipe, and obtaining an alkali liquor product if the pH value is consistent with the pH value of the target alkali liquor in the S1.

The beneficial effects of the invention are as follows:

1. In the invention, water enters the mixer in a tangential manner from the periphery of the container to form a rotary flow state, red mud powder is thrown into the rotary flow water from the top of the container, and the primary mixing of the red mud powder and the water in the mixer is realized; the stirrer is internally provided with the reflux plate, the reflux plate is fixed in the mixer, alkali liquor is forced to flow out from the periphery of the reflux plate, and red mud powder gradually converges towards the center in the original rotary flow process of the alkali liquor is destroyed in the area above the reflux plate, so that the red mud powder and water are fully mixed, and the mixing efficiency is improved.

2. According to the invention, the stirring blade is not adopted, so that the abrasion of minerals in the red mud powder to the stirring blade is avoided, meanwhile, as the transmission devices such as the stirring blade are not arranged in the mixer, the inconvenience in operation caused by repeated disassembly and assembly of the transmission devices and the equipment damage caused by the abrasion of the transmission devices are avoided, the red mud powder and water can be fully mixed, and the mixing efficiency is improved.

3. The device provided by the invention has the important functions of adjusting the opening of the valve, detecting the pH value and detecting the viscosity, can realize the accurate control of the red mud alkali liquor yield and the solution pH value in the dealkalization process, greatly improves the flexibility and controllability of the production process, ensures that the property of the output alkali liquor is stable and controllable, can adapt to red mud raw materials with different properties, and has high process stability.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention.

FIG. 1 is a schematic structural diagram of the dealkalization apparatus for red mud in example 1,

Fig. 2 is a schematic flow chart of the dealkalization method of red mud in example 2.

Wherein, 1, a mixer; 11. a red mud inlet; 12. a water inlet; 13. a discharge port; 2. a reflow plate; 21. a support rod; 3. a red mud input pipe; 4. a water supply pipe; 5. a discharge pipe; 6. and a return pipeline.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present invention. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

Example 1

A red mud dealkalization device, as shown in fig. 1, comprises: the device comprises a base, a hollow cylindrical mixer 1, a feeding unit and a discharging unit;

The mixer 1 is mounted on a base and divided into three parts in succession from top to bottom: the stirring zone is connected with the feeding zone; the top end of the feeding area is provided with a red mud inlet 11, the side wall of the feeding area is provided with a plurality of water inlets 12, and the directions of the water inlets 12 are along the tangential direction of the side wall of the mixer 1, and are all in a left-handed direction or all in a right-handed direction; the inside of the stirring area is a straight cylinder with the same inner diameter up and down; a discharge hole 13 is formed in the center of the bottom of the discharge area; a reflux plate 2 is arranged above a discharging area in the mixer 1;

the feeding unit comprises a red mud input pipe 3 and a water supply pipe 4; the red mud input pipe 3 is communicated with a red mud inlet 11 at the top end of the mixer 1, and the water supply pipe 4 is communicated with a water inlet 12 at the side wall of the mixer 1;

The discharging unit comprises a discharging pipe 5, and the discharging pipe 5 is communicated with a discharging hole 13 of the mixer 1.

Through the arrangement, water enters the mixer in a tangential manner from the periphery of the container to form a rotary flow state, a stirring device is not needed, and red mud powder is thrown into the rotary flow water along with flowing air from the top of the container, so that the primary mixing of the red mud powder and the water in the mixer is realized; in the stirring process, the dispersed red mud powder gradually moves downwards in a vortex shape in water and gradually converges towards the center until encountering the reflux plate 2, the red mud powder is destroyed in a tendency of converging towards the center, and enters the discharging area from the periphery of the reflux plate 2. In the process of uniform mixing, the free alkali and other soluble salts in the red mud are leached into water serving as a diluent, and alkali liquor output by a discharge port 13 is filtered or subjected to other solid-liquid separation methods, so that dealkalized red mud can be obtained.

In the mixer 1, the stirring area gradually reduces to the internal diameter of the discharge hole 13, and the discharge area is arranged between the stirring area and the discharge hole 13, and the internal diameter gradually reduces to improve the flow speed and prevent mineral powder from depositing at the position because the rotational flow stirring state of the stirring area and the stirring area is separated by the reflux plate 2.

The water inlets 12 are uniformly distributed along the same height, the number of the water inlets 12 is 2-6, preferably, the number of the water inlets 12 is 4, and the angle of the adjacent water inlets on the side wall is 90 degrees.

The vertical inclination angle of the water inlet 12 is adjustable, and because the water inflow is not fixed, and the rotation power of the liquid in the stirring area is driven by the water flow of the water inlet 12, when the water inflow is smaller, the vertical inclination angle of the water inlet 12 needs to be adjusted to improve the stirring effect of the water inflow.

The reflux plate 2 is arranged on the inner wall of the discharging area through the supporting rod 21, so that disturbance to the stirring area above is avoided.

The reflux plate 2 is perpendicular to the side wall of the mixer 1, the reflux plate 2 is a circular plate with the diameter smaller than the inner diameter of the mixer 1, the upper surface and the side wall of the circular plate are provided with wear-resistant layers, and the power devices such as stirring blades and the like are omitted in the device of the embodiment, but the reflux plate 2 is positioned in the center of the alkali liquor which flows in a rotating way, so that the reflux plate is worn by mineral powder in the alkali liquor; the reflux plate 2 is used as the only device which is easy to be worn by mineral powder in the device, and the wear-resistant layer is arranged on the upper surface and the side wall of the reflux plate 2, so that the wear degree can be reduced, and the replacement period of the reflux plate 2 can be prolonged.

A fan is arranged on the red mud input pipe 3, and flowing air conveyed by the fan drives red mud powder to enter the red mud inlet 11 and be thrown into the water flowing in a rotating mode from the upper side, so that uniform mixing is facilitated.

The water delivery amount of the water delivery pipe 4 is adjustable, the wind speed of the fan of the red mud input pipe 3 is adjustable, the proportion of the red mud to water can be adjusted according to the components of the red mud to be treated, and the water level of the stirring area can be adjusted according to the amount of the red mud to be treated.

The discharge pipe 5 is internally provided with a pH value detection device and a viscosity detection device which are used for detecting the pH value and the viscosity of the alkali liquor output by the discharge port 13 so as to further adjust the water inflow and the red mud input.

The discharging pipe 5 is communicated with the stirring area of the mixer 1 through a returning pipe 6, a one-way valve is arranged at the opening end of the stirring area of the returning pipe 6, liquid in the stirring area is prevented from entering the discharging pipe 5 through the returning pipe 6, and preferably, a conveying pump is arranged on the returning pipe 6 so as to provide power for lifting substances in the pipe.

The viscosity was measured using: NDJ-4 pointer-type online viscometer;

The liquid flow was measured using: LUGB-SUP-J medium temperature liquid flow meter;

the measurement of the wind speed and flow rate of the red mud feed is as follows: TMF-I ball valve plug-in type thermal gas mass flowmeter.

Example 2

The red mud dealkalization method using the red mud dealkalization apparatus in example 1, as shown in fig. 2, includes the following steps:

S2, inputting water into the mixer 1 in FIG. 1 through a feeding unit according to the water quantity obtained in the S1, and inputting red mud into the mixer through the feeding unit according to the red mud quantity obtained in the S1 after the stirring area forms a rotary flow state;

S3, in the mixer, the red mud falls into the water flowing in a rotating way, is mixed and stirred to form alkali liquor, enters a discharge area at the outer side of the reflux plate 2, and flows out through a discharge hole 13;

And S4, adjusting the water delivery amount in the S2 and the red mud amount according to the pH value and the viscosity of the alkali liquor measured at the position of the discharging pipe 5, and obtaining an alkali liquor product if the pH value is consistent with the pH value of the target alkali liquor in the S1.

Through the arrangement, the accurate control of the output of the red mud alkali liquor and the pH value of the solution can be realized, the flexibility and the controllability of the production process are greatly improved, the property of the output alkali liquor is stable and controllable, and the method can be suitable for red mud raw materials with different properties.

In the process, a minimum flow capable of ensuring sufficient stirring is obtained through experiments, and the minimum flow can maintain the water body in the mixer in a rotational flow state capable of ensuring sufficient stirring; when the flow is regulated, the actual flow is not lower than the minimum flow, so that the subsequent process requirements can be met;

Specifically, the minimum flow is an empirical value obtained through experiments, and the mixing degree of the red mud and water is measured after the flow is changed for a plurality of times, so that the minimum value is found.

In S1, the target lye is: it is desirable to obtain a red mud slurry by mixing red mud obtained at a discharge port with water.

In S4, the alkali liquor refers to: red mud slurry formed by mixing red mud obtained at a discharge hole with water.

In S2, the input red mud is dry red mud, the particle size range of powder is 100-500 mu m, preferably 250 mu m, and the red mud can be driven by flowing air in a red mud input pipe of a feeding unit to be thrown into a mixer.

S2, throwing red mud into the mixer through the feeding unit after the water quantity in the stirring area reaches a set water level; preferably, the water level of the stirring area is lower than the position of the water inlet 12 and higher than the position of the reflux plate 2, so that a stable rotary flowing water body is formed.

S4, if the measured pH value is larger than the pH value of the target alkali liquor, continuing to detect the viscosity of the alkali liquor; if the viscosity of the alkali liquor is smaller than the optimal value, detecting the red mud component, adjusting the red mud quantity required to be input in the S1 and the water quantity used for dilution, and then continuously measuring the pH value of the alkali liquor product; if the viscosity of the alkali liquor is greater than the optimal value, calculating the water inflow which should be continuously increased, correcting the water amount in S2, and then continuously measuring the pH value of the alkali liquor product.

S4, if the measured pH value is smaller than the pH value of the target alkali liquor, continuing to detect the viscosity of the alkali liquor; if the viscosity of the alkali liquor is greater than the optimal value, detecting the red mud component, adjusting the red mud quantity required to be input in the S1 and the water quantity used for dilution, and then continuously measuring the pH value of the alkali liquor product; if the viscosity of the alkali liquor is greater than the optimal value, calculating the input red mud quantity which should be continuously increased, correcting the input red mud quantity in S2, and then continuously measuring the pH value of the alkali liquor product.

The viscosity was measured because: the viscosity will be changed by the different ratio of red mud to inlet water, the viscosity is detected because the pH is required in the course of the subsequent experiments, and the pH is adjusted by adjusting the amount of inlet water or the amount of red mud, and the specific adjustment of which of the two amounts is required to be determined according to the viscosity: if the viscosity is too high, the pH can be adjusted by only reducing the amount of red mud powder entering or increasing the amount of water entering to lower the pH, and if the viscosity is low, increasing the amount of red mud powder entering or decreasing the amount of water entering.

If the alkali liquor output in the step S4 is unqualified, the alkali liquor is required to be returned to the mixer 1 through a return pipeline 6 for continuous treatment.

The existing red mud dealkalization method generally needs to wash a batch of red mud for a plurality of times: mixing red mud with water, removing dilution water after enough sodium ions are dissolved in the water, mixing the treated red mud with pure water again, removing dilution water after enough sodium ions are dissolved in the water, and repeating for a plurality of times to obtain dealkalized red mud. This is because sodium ions which are not dissolved out in the red mud are dissolved out into the dilution water continuously in the process of changing the dilution water continuously, and the red mud can be stabilized to an equilibrium state after a plurality of times. By adopting the water-washing alkali-removing method, the method has the advantages that the method is more sufficient in reaction due to the high-efficiency red mud dispersing effect, the full stirring effect of red mud particles and water in the dispersing process and the effect of a reflux plate for prolonging the stay time of the red mud in the solution, and compared with the method of adopting stirring blades to carry out mechanical stirring, the method can reduce the times of water washing, and the water washing method is proved by experiments, the times of specific reduction are different according to the different red mud types, and generally, the times of water washing can be reduced by about 25%.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The red mud dealkalizing device is characterized by comprising a base, a hollow cylindrical mixer, a feeding unit and a discharging unit;

The mixer is arranged on the base and is divided into three parts from top to bottom: the stirring zone is connected with the feeding zone; the top end of the feeding area is provided with a red mud inlet, the side wall of the feeding area is provided with a plurality of water inlets, and the directions of the water inlets are along the tangential direction of the side wall of the mixer, and are all left-handed or all right-handed; the inside of the stirring area is a straight cylinder with the same upper and lower inner diameters; a discharge hole is formed in the center of the bottom of the discharge area; a reflux plate is arranged above a discharging area in the mixer, and the reflux plate is perpendicular to the side wall of the mixer;

The feeding unit comprises a red mud input pipe and a water supply pipe; the red mud input pipe is communicated with the red mud inlet at the top end of the mixer, and the water supply pipe is communicated with the water inlet at the side wall of the mixer;

the discharging unit comprises a discharging pipe, and the discharging pipe is communicated with the discharging port of the mixer.

2. The red mud dealkalization device as claimed in claim 1, wherein,

In the mixer, the inner diameter of the stirring area towards the discharge hole is gradually reduced.

3. The red mud dealkalization device as claimed in claim 1, wherein,

A plurality of water inlets are uniformly distributed along the same height, and the number of the water inlets is 2-6; preferably, the number of the water inlets is 4, and the angle between adjacent water inlets on the side wall is 90 degrees;

optionally, the upper and lower inclination angle of the water inlet is adjustable.

4. The red mud dealkalization device as claimed in claim 1, wherein,

The reflux plate is arranged on the inner wall of the discharging area through a supporting rod;

optionally, the reflux plate is perpendicular with the blender lateral wall, the reflux plate is the plectane that the diameter is less than the blender internal diameter, and the upper surface and the lateral wall of plectane are provided with the wearing layer.

5. The red mud dealkalization device as claimed in claim 1, wherein,

A fan is arranged on the red mud input pipe;

Optionally, the water delivery amount in the water delivery pipe is adjustable, and the wind speed of a fan of the red mud input pipe is adjustable;

optionally, a pH value detection device and a viscosity detection device are arranged in the discharging pipe.

6. A red mud dealkalization method by the red mud dealkalization apparatus as claimed in any one of claims 1 to 5, characterized by comprising the steps of:

S1, obtaining the red mud quantity required to be input and the water quantity used for dilution according to the red mud components and the pH value of target alkali liquor; s2, inputting water into the mixer through the feeding unit according to the water quantity obtained in the S1, and inputting red mud into the mixer through the feeding unit according to the red mud quantity obtained in the S1 after the stirring area forms a rotary flow state;

7. A red mud dealkalization method according to claim 6, wherein,

In S2, the input red mud is dry red mud, and the particle size of the powder is 100-500 mu m, preferably 250 mu m.

8. A red mud dealkalization method according to claim 6, wherein,

S2, throwing red mud into the mixer through the feeding unit after the water quantity in the stirring area reaches a set water level; preferably, the water level of the stirring zone is lower than the water inlet position and higher than the reflux plate position.

9. A red mud dealkalization method according to claim 6, wherein,

10. The red mud dealkalization method of claim 6, wherein in S4, if the measured pH value is smaller than the target alkali liquor pH value, the viscosity of the alkali liquor is continuously detected; if the viscosity of the alkali liquor is greater than the optimal value, detecting the red mud component, adjusting the red mud quantity required to be input in the S1 and the water quantity used for dilution, and then continuously measuring the pH value of the alkali liquor product; if the viscosity of the alkali liquor is greater than the optimal value, calculating the input red mud quantity which should be continuously increased, correcting the input red mud quantity in S2, and then continuously measuring the pH value of the alkali liquor product.