CN217556025U - Device for recovering iron oxide by utilizing red mud carbon fixation and dealkalization - Google Patents

Abstract

The application relates to a device for recovering iron oxide by utilizing red mud carbon fixation and dealkalization, which comprises: a carbonization reactor, a filter press, a biofuel shaft kiln, a magnetic separator and a sludge storage tank; the discharge port of the carbonization reactor is connected with the feed port of the filter press, the discharge port of the filter press is connected with the feed port of the biofuel shaft kiln, the discharge port of the biofuel shaft kiln is connected with the magnetic separator, and the tail end discharge port of the magnetic separator is communicated with the sludge storage tank. The technical scheme of the application effectively solves the problem of environmental pollution caused by red mud in the prior art.

Description

Device for recovering iron oxide by utilizing red mud carbon fixation and dealkalization

Technical Field

The application relates to the technical field of red mud recycling, in particular to a device for recycling ferric oxide by utilizing red mud carbon fixation and dealkalization.

Background

Global warming is a consequence of global climate change caused by human behavior. "carbon" is a natural resource composed of carbon elements such as petroleum, coal, wood, and the like. The "carbon" is much more consumed and the very "carbon dioxide" that causes global warming is also much more produced. With the activities of human beings, global warming also affects the life style of people, and brings more and more problems. In the technical aspect, carbon Capture and Sequestration (CCS), a promising technology, is to collect carbon dioxide generated from emission sources such as large power plants, iron and steel plants, chemical plants and the like, and store the carbon dioxide by various methods to prevent the carbon dioxide from being emitted into the atmosphere, so as to achieve the goal of carbon neutralization, promote the pollution source treatment, reduce the emission of pollutants while reducing carbon, and further generate a significant synergistic effect with the improvement of environmental quality.

The biomass particle carbonized fuel is a novel fuel continuously produced by various biomasses such as crop straws, bagasse pith, palm and the like through complex processes such as drying, transformation, mixing, molding, carbonization and the like, has the same property with coal, is a high-efficiency, renewable and environment-friendly biomass fuel which can be used for various combustors, biomass boilers, melting furnaces, biomass power generation and the like, and is a zero-pollution fuel in international certification.

In the process of refining alumina from aluminum ore, the treatment of aluminum ore with strongly basic sodium hydroxide produces a large amount of solid waste (red mud), which generally yields 1.0-2.0 tons of red mud for every 1 ton of alumina produced. Red mud has the undesirable characteristics of high saline-alkali property (pH 10.0-12.0), corrosivity, leaching toxicity, radioactivity and the like, the red mud is treated in an open-air stacking mode at present, the stacking of a large amount of red mud not only needs specific equipment and expensive maintenance cost, but also needs to occupy a large amount of land, the red mud leachate is strong-alkaline (pH is more than 12.0), and the permeation of the red mud can pollute soil and underground water; the red mud is in a plastic flow state, and the collapse of a storage yard can also generate a serious ecological disaster, which becomes a serious problem which always troubles the development of the aluminum industry. Under the condition of natural piling of the red mud, some plants can grow after 10-20 years, and the vegetation is recovered slowly.

SUMMERY OF THE UTILITY MODEL

The application provides a device for recovering iron oxide by utilizing red mud carbon fixation and dealkalization, which is used for solving the problem of environmental pollution caused by red mud in the prior art.

In order to solve the above problems, the present application provides a device for recovering iron oxide by utilizing red mud carbon fixation and dealkalization, comprising: a carbonization reactor, a filter press, a biofuel shaft kiln, a magnetic separator and a sludge storage tank; the discharge port of the carbonization reactor is connected with the feed inlet of the filter press, the discharge port of the filter press is connected with the feed inlet of the biofuel shaft kiln, the discharge port of the biofuel shaft kiln is connected with the magnetic separator, and the tail end discharge port of the magnetic separator is communicated with the sludge storage tank.

Further, the biofuel shaft kiln comprises: the kiln body comprises a feed inlet, a discharge outlet and an air inlet, wherein the feed inlet is arranged at the top of the kiln body, and the discharge outlet and the air inlet are both arranged at the bottom of the kiln body; the slow descending assembly is arranged inside the kiln body and used for burning red mud with biofuel introduced from the feed inlet in the slow descending assembly and slowing down the descending of the red mud, and the red mud is magnetized upwards in the kiln body.

Further, slowly fall the subassembly and include first slowly fall the arc ring, and first slowly fall the arc ring and install on the kiln body, and the middle part of first slowly falling the arc ring has the via hole, and first slowly falls the arc ring and is concave down towards the top of kiln body.

Further, the number of the contour lines of the first slowly descending arc-shaped ring cut by the central axis of the kiln bodyThe study model is as follows: y = aX ² (ii) a X is the abscissa; y is a vertical coordinate; a is a preset coefficient which is more than 0.001 and less than 0.9.

Further, slowly fall the subassembly and still include the second and slowly fall the arc ring, the second slowly falls the axis of arc ring and coincides mutually with the axis of kiln body, the upper surface that the second slowly falls the arc ring is recessed arc, the second slowly falls the middle part of the last cambered surface of arc ring to slowly fall the highly reduction at the edge of the last cambered surface of arc ring gradually, the first projection of slowly falling the arc ring along the axis of kiln body and the projection of second slowly falling the arc ring along the axis of kiln body coincide mutually.

Furthermore, the area of the projection of the first slow descending arc-shaped ring along the central axis of the kiln body and the area of the projection of the second slow descending arc-shaped ring along the central axis of the kiln body are overlapped, and the area of the first slow descending arc-shaped ring is 1/5 to 4/5 of the area of the projection of the first slow descending arc-shaped ring along the central axis of the kiln body.

Furthermore, the first slowly-descending arc-shaped rings are arranged in a plurality of height directions along the central axis of the kiln body, and the second slowly-descending arc-shaped rings are arranged in a plurality of one-to-one correspondence with the first slowly-descending arc-shaped rings.

Furthermore, the device also comprises a ball mill, a filter sieve, a conveyor, a stirring tank, a first conveying pump and a second conveying pump, wherein a discharge port of the ball mill is connected with a feed port of the filter sieve, a discharge port of the filter sieve is correspondingly arranged with a feed end of the conveyor, a discharge end of the conveyor is connected with a feed port of the stirring tank, a discharge port of the stirring tank is connected with a feed port of the first conveying pump, a discharge port of the first conveying pump is connected with a feed port of the carbonization reactor, and a discharge port of the carbonization reactor is connected with a discharge port of the second conveying pump.

Further, the magnetic separator comprises a plurality of magnetic separators with different magnetism, and the magnetism of the magnetic separator far away from the shaft kiln is larger than that of the magnetic separator near the shaft kiln.

Further, the magnetic separator comprises a weak magnetic separator, a medium magnetic separator and a strong magnetic separator, the weak magnetic separator is close to one side of the shaft kiln, the strong magnetic separator is located on the side far away from the shaft kiln, and the medium magnetic separator is located between the weak magnetic separator and the strong magnetic separator.

Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:

according to the technical scheme, the biological fuel is carbonized in the carbonization reactor and is mixed with the red mud, the mixture enters the calcination and magnetization of the biological fuel shaft kiln through the filter press, then the waste materials selected by the magnetic separator enter the mud storage tank to be utilized or treated in the next step through selection of the magnetic separator, for example, bricks are manufactured, so that the waste utilization of the red mud can be effectively realized, and the pollution of the red mud to the environment is reduced. The technical scheme of the application effectively solves the problem of environmental pollution caused by red mud in the prior art.

Drawings

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

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive labor.

FIG. 1 shows a process configuration schematic of an apparatus of an embodiment of the present application;

FIG. 2 shows a schematic structural view of the biofuel shaft kiln of the apparatus of FIG. 1;

FIG. 3 shows a schematic top view of the biofuel shaft kiln of FIG. 1;

fig. 4 shows a schematic internal structural view of the kiln body of the biofuel shaft kiln of fig. 1.

Wherein the figures include the following reference numerals:

1. a ball mill; 2. filtering and screening; 3. a conveyor; 4. a stirring tank; 5. a first delivery pump; 6. a carbonization reactor; 7. a second delivery pump; 8. a filter press; 9. a biofuel shaft kiln; 90. a kiln body; 91. a discharge port; 92. an air inlet; 93. a slow descent component; 931. a first slowly descending arc-shaped ring; 932. a second slowly descending arc-shaped ring; 94. a feeding structure; 95. a winch; 96. a skip car; 97. a bell cap structure; 10. a magnetic separator; 13. a mud storage pool; 14. red mud; 15. a sulfide; 16. water; 18. mud cakes; 19. and (5) filtering water.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making creative efforts shall fall within the protection scope of the present application.

As shown in fig. 1 to 4, the present embodiment provides an apparatus for recovering iron oxide by using red mud carbon-fixation dealkalization, including: a carbonization reactor 6, a filter press 8, a biofuel shaft kiln 9, a magnetic separator 10 and a sludge storage tank 13. The discharge port of the carbonization reactor 6 is connected with the feed port of the filter press 8, the discharge port of the filter press 8 is connected with the feed port of the biofuel shaft kiln 9, the discharge port of the biofuel shaft kiln 9 is connected with the magnetic separator 10, and the discharge port at the tail end of the magnetic separator 10 is communicated with the sludge storage tank 13.

According to the technical scheme of the embodiment, the biofuel is carbonized in the carbonization reactor and mixed with the red mud, the mixture enters the calcination and magnetization of the biofuel shaft kiln through the filter press, and then the waste materials selected by the magnetic separator enter the mud storage tank for further utilization or treatment, such as brick manufacturing and the like, through selection of the magnetic separator, so that the waste utilization of the red mud can be effectively realized, and the pollution of the red mud to the environment is reduced. The technical scheme of the application effectively solves the problem of environmental pollution caused by red mud in the prior art.

As shown in fig. 2 to 4, the biofuel shaft kiln comprises: kiln body 90 and slowly fall subassembly 93, kiln body 90 includes feed inlet, discharge gate 91 and air intake 92, and the feed inlet setting is at the top of kiln body 90, and discharge gate and air intake all set up the bottom at kiln body 90. The slow descending assembly 93 is arranged inside the kiln body 90 and is used for burning red mud with biofuel introduced from the feed inlet in the slow descending assembly and slowing down the descending of the red mud, and the red mud is magnetized in the kiln body 90.

According to the technical scheme, the red mud enters the kiln body through the feed inlet, and the descending speed of the red mud can be slowed down by the descending component through the descending component in the kiln body, so that the time of the red mud in the kiln body is longer, the preheating, burning and cooling time of the red mud is further ensured, the burning and magnetizing effects of the red mud are better, and the carbon emission can be greatly reduced by adopting the combustion of the biofuel. This embodiment has solved the problem of the environmental pollution that the red mud caused among the prior art effectively.

As shown in fig. 3, in the technical solution of this embodiment, the slow-falling assembly 93 includes a first slow-falling arc-shaped ring 931, the first slow-falling arc-shaped ring 931 is installed on the kiln body 90, a through hole is formed in the middle of the first slow-falling arc-shaped ring 931, and the first slow-falling arc-shaped ring 931 is concave downward toward the top of the kiln body 90. The upper surface of the first slowly descending arc-shaped ring 931 is a concave arc, so that the descending speed of the red mud is greatly reduced, and the concave arc has better speed buffering than an inclined downward plane when falling. It should be noted that the first slow-descending arc-shaped ring 931 may be a closed arc-shaped ring, or may be formed by a plurality of first sub slow-descending arc-shaped rings at intervals.

As shown in fig. 4, in the technical solution of this embodiment, a mathematical model of a contour line of the first descent control arc-shaped ring 931 cut through the central axis of the kiln body 90 is as follows: y = aX2, X being the abscissa, Y being the ordinate, a being a predetermined coefficient greater than 0.001 and less than 0.9, the predetermined coefficient being related to the particles of red mud, the composition of the red mud mixture. The arc of the upper surface of the first slowly descending arc-shaped ring 931 meets the requirements, the too steep upper surface of the first slowly descending arc-shaped ring 931 causes the descending speed of the red mud to be fast, the preheating, the burning, the magnetizing and the like are insufficient, and the too gentle upper surface of the first slowly descending arc-shaped ring 931 causes the red mud to be accumulated easily in the descending process.

In the solution of this embodiment (not shown in the drawings), the upper arc surface of the first descending arc-shaped ring 931 has a plurality of protrusions. The arrangement of the plurality of protrusions enables the surface area of the red mud to be easily increased, and can further slow down the descending speed of the red mud, and the red mud is not easily formed to accumulate on the upper surface of the first slow descending arc-shaped ring 931. It should be noted that the plurality of protrusions are also protrusions on the arc surface, so that the red mud is not stuck on the first descent arc ring 931 to cause the accumulation of the red mud.

As shown in fig. 4, in the technical solution of this embodiment, the slow-descending assembly 93 further includes a second slow-descending arc-shaped ring 932, a central axis of the second slow-descending arc-shaped ring 932 coincides with the central axis of the kiln body 90, an upper surface of the second slow-descending arc-shaped ring 932 is a concave arc, a height from a middle of an upper arc surface of the second slow-descending arc-shaped ring 932 to an edge of the upper arc surface of the slow-descending arc-shaped ring gradually decreases, and a projection of the first slow-descending arc-shaped ring 931 onto the central axis of the kiln body 90 coincides with a projection of the second slow-descending arc-shaped ring 932 onto the central axis of the kiln body 90. The structure not only prolongs the moving track of the red mud in the kiln body 90, but also prolongs the retention time of the red mud in the kiln body 90, which greatly improves the preheating, combustion and magnetizing effects. The red mud moves on the first slowly descending arc-shaped ring 931 and then falls down on the second slowly descending arc-shaped ring 932 under the action of gravity. It should be noted that when the red mud reaches the first slow descending arc-shaped ring 931, the red mud also passes through the red mud distributor in the kiln body 90, so that the red mud more uniformly enters the first slow descending arc-shaped ring 931. The projection of the first slow-descending arc-shaped ring 931 on the central axis of the kiln body 90 coincides with the projection of the second slow-descending arc-shaped ring 932 on the central axis of the kiln body 90, so that the situation that the red mud directly falls to the bottom of the kiln body 90 from the first slow-descending arc-shaped ring 931 does not occur. In addition, the falling speed of the red mud can be partially adjusted through the wind speed and the wind pressure of the air inlet.

As shown in fig. 4, in the technical solution of this embodiment, an area where a projection of the first slow-falling arc-shaped ring 931 on the central axis of the kiln body 90 coincides with a projection of the second slow-falling arc-shaped ring 932 on the central axis of the kiln body 90 occupies between 1/5 and 4/5 of an area of the projection of the first slow-falling arc-shaped ring 931 on the central axis of the kiln body 90. The structure enables the time and the speed of the red mud in the kiln body 90 to reach better values. It should be noted that the vertical distance between the first slow-descending arc-shaped ring 931 and the second slow-descending arc-shaped ring 932 corresponding to the first slow-descending arc-shaped ring 931 can be adjusted, the first slow-descending arc-shaped ring 931 is connected with the kiln body 90 through a fastener, and the second slow-descending arc-shaped ring 932 is connected to the central column arranged on the kiln body 90 through a fastener. The overlap area between the first and second slow descent arcuate rings 931, 932 is also adjustable. The upper cambered surface of the second slow descending arc-shaped ring 932 is provided with a bulge, and the mathematical model of the upper surface of the second slow descending arc-shaped ring 932 cut by the cross section of the central axis of the kiln body 90 is a hyperbolic curve.

As shown in fig. 4, in the technical solution of this embodiment, a plurality of first slow-falling arc-shaped rings 931 are arranged along the height direction of the central axis of the kiln body 90, and a plurality of second slow-falling arc-shaped rings 932 are arranged in one-to-one correspondence with the first slow-falling arc-shaped rings 931. The structure further prolongs the moving track of the red mud in the kiln body 90 and prolongs the retention time of the red mud in the kiln body 90.

As shown in fig. 2, in the technical solution of this embodiment, the biofuel shaft kiln further includes a loading structure 94, a winch 95 and a skip car 96, the skip car 96 is movably disposed on the loading structure 94, a first end of the loading structure 94 is located on the ground, a second end of the loading structure 94 is located on the top end of the kiln body 90, and the winch 95 is connected to the skip car 96 to drive the skip car 96 to move on the loading structure 94. The structure enables the feeding of the red mud to be easily automated.

As shown in fig. 2, in the technical solution of this embodiment, the biofuel shaft kiln further includes a bell-jar structure 97, and the bell-jar structure 97 is disposed at the feed inlet of the kiln body 90 to screen the red mud. The arrangement of the bell-cap structure 97 can realize a good screening effect on the red mud.

Therefore, the biomass fuel shaft kiln for the magnetic adsorption of the red mud uses the biomass particle carbonized fuel as an energy source. The biomass fuel shaft kiln comprises a shaft kiln body, wherein the shaft kiln body comprises a kiln body steel structure and a kiln liner, and the top of the shaft kiln body is provided with an exhaust funnel, an opening and closing device, a bell cap lifting mechanism (a bell cap structure 97) and a kiln top device; the bottom of the shaft kiln body is provided with a kiln bottom device, a star-shaped ash discharger (a discharge hole 91) and an air inlet pipe (an air inlet 92); a feeding system (a feeding structure 94) is arranged on the side of the shaft kiln body and consists of a steel slide rail and a winch.

The shaft kiln body is composed of a kiln body steel structure and a kiln liner, and an exhaust funnel and an opening and closing device are arranged on the kiln top device. The bell cap lifting mechanism consists of two material receiving hoppers and two lifting material bells which are overlapped up and down. Controlling the material distribution, adding and preventing the large material from entering the kiln.

The kiln cylinder is internally provided with a preheating zone (about 1/3 section at the upper part of the cylinder), a calcining zone (1/3 section in the middle of the cylinder) and a cooling zone (1/3 section at the lower part of the cylinder) from top to bottom in sequence. The red mud raw material is heated in a preheating zone and calcined in a calcining zone, the lower part is a cooling zone, and the magnetic product sinks in the cooling zone. The calcining barrel is internally provided with a plurality of groups of arc-shaped round tables and inverted arc-shaped round tables, so that the falling speed of the red mud can be slowed down, and the red mud can be fully calcined.

A heat source of the shaft kiln is provided by biomass particle carbonized fuel, and the biomass particle carbonized fuel and the red mud raw material are mixed and then enter the shaft kiln together from a feed inlet above the kiln cylinder.

A feed inlet is arranged above the kiln top, a bell-cap lifting device is arranged at the feed inlet to control the red mud raw material feeding amount, and a high-temperature radar level gauge is used for detecting the position of the material. A high-temperature radar level gauge is further arranged in the kiln body 90 for measuring the position of the red mud material in the kiln body 90. The high-temperature radar level indicator is arranged at the position of the preheating zone, so that the height of the material can be effectively monitored.

The kiln body is also internally provided with a high-temperature pressure sensor which is arranged on the inner wall of the smoke exhaust tube and used for measuring the pressure in the kiln.

The kiln cylinder (kiln body 90) is also internally provided with 90 high-temperature sensors for monitoring the temperature of the preheating zone, the calcining zone and the cooling zone. Wherein, each part of the preheating zone, the calcining zone and the cooling zone is respectively and uniformly provided with 3 high-temperature sensors, the 3 temperature sensors are arranged in the positions surrounding the kiln, and the included angle is 120 degrees; 1 temperature sensor is arranged in the smoke exhaust hole.

One side of the kiln body 90 is provided with a feeding structure 30 which is composed of a winch, a skip car and a steel slide rail and is used for conveying a mixture of the red mud raw material and the biomass granular carbonized fuel.

A star-shaped ash discharger is arranged below the shaft kiln to discharge the magnetic red mud. An air inlet pipe is arranged below the shaft kiln, and air is supplied at the bottom of the kiln.

The red mud is firstly processed into 30-90 mm blocks by a crusher and is calcined on a shaft kiln, and the shaft kiln is characterized in that the red mud cannot be over-burnt or under-burnt, and the used combustion is biomass particle carbonized fuel. Sieving the calcined product, dedusting the carbon dioxide generated by calcination through a dust remover arranged at the top of the furnace, storing the pure carbon dioxide in a gas storage cabinet, further purifying and compressing the carbon dioxide, and using the carbon dioxide as an industrial drive oil extraction, a biological gas fertilizer, a refrigerant, a chemical raw material and the like.

The specific red mud calcining and magnetism attaching method adopting the shaft kiln for red mud calcining and magnetism attaching comprises the following steps:

s1, firstly, crushing and screening dry red mud selected from ores by using a crusher, conveying the red mud with the bulk degree of 30-90 mm into an underground receiving bin by using a forklift, conveying the red mud to a storage bin in front of a kiln by using an electromagnetic vibrating feeder and a large-inclination-angle belt conveyor to carry out screening by using a single-layer vibrating screen, screening out crushed materials in the red mud, and conveying the crushed materials with the undersize of less than 30mm into the crushed material bin for outward transportation.

S2, mixing the qualified red mud raw material with the biomass particle carbonized fuel, putting the red mud mixed with the biomass particle carbonized fuel into a hopper of a hoist, hoisting the red mud to a feeding bin by the hoist, and controlling the feeding of the feeding bin by a bell-cap lifting device at the top of the kiln.

And S3, after the red mud raw material is preheated, calcined and cooled in the shaft kiln, discharging the red mud raw material into a kiln bottom material bin through a star-shaped ash discharging machine arranged below the kiln, and entering the next procedure.

In the biomass fuel kiln, the airflow flows from bottom to top, and is opposite to the descending of mineral aggregates. The red mud raw material firstly reaches the preheating stage of the kiln cylinder, the temperature is 300-400 ℃, and the red mud raw material absorbs the heat radiated in the kiln cylinder at the stage. The preheated red mud raw material is further lowered to the calcining stage of the kiln barrel, and the temperature reaches 600-700 ℃ in the calcining stage. And (3) continuously reducing the calcined magnetic red mud to a cooling stage, wherein the temperature reaches 120-150 ℃, conveying the calcined magnetic red mud to a large-inclination-angle belt conveyor from a vibration feeder below a kiln bottom bin, and conveying the magnetic red mud to a dry grinding workshop for multi-stage magnetic separation to extract magnetic iron oxide. And a large amount of carbon dioxide gas is released by calcination, the temperature of the gas is reduced to be lower than 300 ℃ when the gas reaches the exhaust funnel, the gas is discharged to a dust remover, and the gas enters a carbon dioxide gas storage cabinet after being further purified.

The biomass fuel shaft kiln for the magnetic adsorption of the red mud is provided by the embodiment, biomass particles are used for carbonizing fuel, and the feeding and airflow are controlled to be reversed. The equipment has the advantages of full utilization of heat, uniform calcination and magnetic adsorption, reasonable occupied area, high space utilization rate, high yield and low investment cost, and is suitable for large-scale industrial production and application.

As shown in fig. 1, in the technical solution of this embodiment, the apparatus further includes a ball mill 1, a filter sieve 2, a conveyor 3, an agitator tank 4, a first delivery pump 5 and a second delivery pump 7, a discharge port of the ball mill 1 is connected to a feed port of the filter sieve 2, a discharge port of the filter sieve 2 is correspondingly disposed to a feed end of the conveyor 3, a discharge end of the conveyor 3 is connected to a feed port of the agitator tank 4, a discharge port of the agitator tank 4 is connected to a feed port of the first delivery pump 5, a discharge port of the first delivery pump 5 is connected to a feed port of the carbonization reactor 6, and a discharge port of the carbonization reactor 6 is connected to a discharge port of the second delivery pump 7.

As shown in FIG. 1, in the solution of the present embodiment, the magnetic separator 10 comprises a plurality of magnetic separators with different magnetism, and the magnetism of the magnetic separator far away from the shaft kiln is greater than that of the magnetic separator near the shaft kiln.

According to another aspect of the application, a method for recovering iron oxide by utilizing red mud carbon sequestration and dealkalization is also provided, and the method for recovering iron oxide by utilizing red mud carbon sequestration and dealkalization adopts the device for recovering iron oxide by utilizing red mud carbon sequestration and dealkalization, and comprises the following steps: s1, grinding solid red mud by using a ball mill; s2, mixing water and the red mud ground in the step S1 according to a liquid-solid mass ratio of 1:3, putting the mixture into a stirrer and stirring the mixture evenly; s3, adding a proper amount of sodium sulfide into the slurry-like red mud to passivate heavy metals in the red mud; s4, allowing the muddy red mud to enter a carbonization reactor through a discharge hole of the stirring tank; s5, the dealkalized red mud slurry enters a plate filter press to be dewatered and subjected to solid-liquid separation, and red mud cakes and filtered water are obtained respectively; s6, putting the mud cakes prepared in the S5 into a shaft furnace for drying and magnetizing roasting, and magnetizing iron oxide in the red mud; s7, feeding the roasted red mud into a three-stage magnetic separator in a powdery state, wherein the three-stage magnetic separator is a weak magnetic separator, a medium magnetic separator and a strong magnetic separator respectively, and separating magnetic iron oxide in the red mud; and S8, after being treated in the S7, the red mud enters a mud storage pool to be stored, organic matter is added into the red mud to improve the red mud, and the red mud is subjected to soil organic treatment.

In the technical scheme of this embodiment, in the step S1, the fineness of the ground red mud is 80 μm square-hole residue not greater than 5%, and the ground red mud passes through a 150 μm square-hole sieve for standby; in the step S4, mechanically stirring at 500rpm in the reaction process, and carrying out gas-liquid-solid three-phase carbonate dealkalization reaction, wherein the pressure of a reaction system is 0.6Mpa and the reaction time is 60min; the temperature of the magnetizing roasting in the step S6 is between 450 and 600 ℃.

The method is combined, so that the method is convenient to operate, high in mechanization degree, large in treatment capacity, efficient and rapid, can effectively degrade and harmlessly treat the high alkalinity of the red mud, and is suitable for industrial production; meanwhile, after the treatment by the process, the absorption and fixation of the carbon dioxide can be completed. The dealkalized red mud can be improved and backfilled after the iron removal is finished.

The application discloses red mud solid carbon dealkalization, retrieve iron oxide system and technology, the utility model relates to a method of utilizing red mud solid carbon dealkalization to retrieve iron oxide who realizes like this, including ball mill 1, filter sieve 2, conveyer 3, red mud agitator tank 4, tubing pump 5, 7, carbonization reactor 6, plate filter 8, shaft furnace 9, magnet separator 10, store up mud pond 13.

The outlet of the ball mill 1 is connected with the inlet of a filter sieve 2, the outlet of the filter sieve 2 is connected with the inlet of a conveyor 3, the tail end of the conveyor 3 is connected with the inlet of a red mud stirring tank 4, the outlet of the red mud stirring tank 4 is connected with the inlet of a pipeline pump 5, the outlet of the pipeline pump 5 is connected with the inlet of a carbonization reactor 6, the outlet of the carbonization reactor 6 is connected with the inlet of a plate filter press 8 through a pipeline pump 7, the outlet of a shaft furnace 9 is connected with the inlet of a magnetic separator 10, the outlet of a weak magnetic separator is connected with the inlet of a medium magnetic separator, the outlet of the medium magnetic separator is connected with the inlet of a strong magnetic separator, and the outlet of the magnetic separator 12 is connected with the inlet of a sludge storage tank 13; the weak magnetic separator, the medium magnetic separator and the strong magnetic separator are obtained by comparing the weak magnetic separator, the medium magnetic separator and the strong magnetic separator, namely, the magnetism of the weak magnetic separator is smaller than that of the medium magnetic separator, and the magnetism of the medium magnetic separator is smaller than that of the strong magnetic separator, so that the selection of magnetic iron oxide is facilitated, and the next step of working procedure is facilitated.

The ball mill 1 is used for crushing and grinding the dry red mud blocks into powder;

the filter sieve 2 is provided with a vibrator and is used for sieving red mud particles with the particle size of 80-150 mu m;

the conveyor 3 is used for conveying granular red mud to the red mud stirring tank 4; the red mud stirring tank 4 is provided with a red mud inlet, a sulfide inlet and a water inlet, and an alkali-resistant coating is coated inside the red mud slurry stirring tank body; a stirrer is arranged in the middle of the tank body;

the pipeline pump 5 is used for conveying the slurry red mud to the carbonization reactor 6;

the bottom of the carbonization reactor 6 is provided with a gas guide pipe, the gas guide pipe is used for providing carbon dioxide gas required by the reaction into the carbonization reactor 6, and a stirring shaft is arranged in the carbonization reactor 6;

the plate-type filter press 8 is used for carrying out filter-pressing solid-liquid separation on the reacted slurry red mud;

the shaft furnace 9 is used for roasting and magnetizing the red mud, and the roasting temperature of the shaft furnace is 450-600 ℃;

the magnetic separator 10 is used for removing magnetic iron oxide from the red mud;

the mud storage tank 13 is used for improving organic matters of the stored red mud, and reclaiming and returning the organized red mud to the field.

A process for carbon fixation and dealkalization of red mud and recovery of ferric oxide comprises the following steps:

s1, grinding solid red mud 14 by using a ball mill 1, wherein the fineness of the ground red mud is 80-150 mu m, the residue on a square hole sieve is not more than 5%, and the ground red mud is sieved by a square hole sieve of 150-300 mu m for later use;

s2, filling the water 16 and the red mud ground in the step S1 into a red mud stirring tank 4 according to the mass-to-volume ratio of 2.5-3.5, and uniformly stirring.

And S3, adding a proper amount of sulfide 15 into the slurry-like red mud to passivate heavy metals in the red mud.

S4, feeding the muddy red mud into a carbonization reactor 6 through an outlet of a red mud stirring tank 4, mechanically stirring at 300-500 rpm in the reaction process, and carrying out gas-liquid-solid three-phase carbonate dealkalization reaction, wherein the pressure of a reaction system is 0.1-0.6 MPa; the reaction time is 30-60 min.

And S5, the dealkalized red mud slurry enters a plate filter press 8 to be dewatered, solid and liquid separated, and red mud cakes 18 and filtered water 19 are respectively obtained.

S6, the mud cake 18 prepared from the S5 enters a shaft furnace 9 (a rotary furnace or a fluidized bed furnace) for drying and magnetizing roasting (450-600 ℃), and the iron oxide in the red mud is magnetized.

And S7, feeding the roasted red mud in a powdery state into a three-stage magnetic separator, namely a weak magnetic separator, a medium magnetic separator and a strong magnetic separator, to separate magnetic iron oxide in the red mud.

And S8, the red mud treated by the S7 enters a mud storage tank 13 for storage, and organic matters are added into the red mud to carry out soil organic treatment on the red mud, so that the treated red mud can be reclaimed.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising a," "8230," "8230," or "comprising" does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.

The above description is merely illustrative of the invention and is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. The utility model provides a utilize red mud carbon fixation dealkalization to retrieve device of iron oxide which characterized in that includes: a carbonization reactor (6), a filter press (8), a biofuel shaft kiln (9), a magnetic separator (10) and a sludge storage tank (13);

the discharge hole of the carbonization reactor (6) is connected with the feed inlet of the filter press (8), the discharge hole of the filter press (8) is connected with the feed inlet of the biofuel shaft kiln (9), the discharge hole of the biofuel shaft kiln (9) is connected with the magnetic separator (10), and the discharge hole at the tail end of the magnetic separator (10) is communicated with the sludge storage tank (13).

2. The apparatus for recovering iron oxide by using red mud carbon sequestration and dealkalization according to claim 1, wherein the biofuel shaft kiln (9) comprises:

the kiln body (90) comprises a feed inlet, a discharge outlet (91) and an air inlet (92), the feed inlet is arranged at the top of the kiln body (90), and the discharge outlet and the air inlet are both arranged at the bottom of the kiln body (90);

the slow descending assembly (93) is arranged inside the kiln body (90) and used for burning the red mud with the biofuel introduced from the feed port and slowing down the descending of the red mud, and the red mud is magnetized in the kiln body (90).

3. The device for recovering iron oxide by utilizing red mud carbon sequestration and dealkalization according to claim 2, wherein the slow descending assembly (93) comprises a first slow descending arc-shaped ring (931), the first slow descending arc-shaped ring (931) is installed on the kiln body (90), a through hole is formed in the middle of the first slow descending arc-shaped ring (931), and the first slow descending arc-shaped ring (931) is downward concave towards the top of the kiln body (90).

4. The device for carbon sequestration and iron oxide recovery from red mud according to claim 3, wherein the mathematical model of the contour line of the first descent arc-shaped ring (931) cut through the central axis of the kiln body (90) is as follows:

Y＝aX ² ；

x is the abscissa;

y is a vertical coordinate;

a is a preset coefficient which is more than 0.001 and less than 0.9.

5. The device for recovering iron oxide by utilizing red mud carbon sequestration and dealkalization according to claim 3, wherein the slow descending component (93) further comprises a second slow descending arc-shaped ring (932), the central axis of the second slow descending arc-shaped ring (932) coincides with the central axis of the kiln body (90), the upper surface of the second slow descending arc-shaped ring (932) is in a concave arc shape, the height from the middle of the upper arc surface of the second slow descending arc-shaped ring (932) to the edge of the upper arc surface of the slow descending arc-shaped ring is gradually reduced, and the projection of the first slow descending arc-shaped ring (931) along the central axis of the kiln body (90) coincides with the projection of the second slow descending arc-shaped ring (932) along the central axis of the kiln body (90).

6. The device for recovering iron oxide by utilizing red mud carbon sequestration and dealkalization as recited in claim 5, characterized in that the area of the projection of the first slow descending arc-shaped ring (931) along the central axis of the kiln body (90) is 1/5 to 4/5 of the area of the projection of the first slow descending arc-shaped ring (931) along the central axis of the kiln body (90) in the overlapping area of the projection of the second slow descending arc-shaped ring (932) along the central axis of the kiln body (90).

7. The device for recovering iron oxide by utilizing red mud carbon sequestration and dealkalization according to claim 5, wherein the first slow-descending arc-shaped rings (931) are arranged in a plurality along the height direction of the central axis of the kiln body (90), and the second slow-descending arc-shaped rings (932) are arranged in a plurality corresponding to the first slow-descending arc-shaped rings (931) one by one.

8. The device for recovering iron oxide by utilizing red mud carbon sequestration and dealkalization according to any one of claims 1 to 7, characterized by further comprising a ball mill (1), a filter sieve (2), a conveyor (3), a stirring tank (4), a first conveying pump (5) and a second conveying pump (7), wherein a discharge port of the ball mill (1) is connected with a feed port of the filter sieve (2), a discharge port of the filter sieve (2) is correspondingly arranged with a feed end of the conveyor (3), a discharge end of the conveyor (3) is connected with a feed port of the stirring tank (4), a discharge port of the stirring tank (4) is connected with a feed port of the first conveying pump (5), a discharge port of the first conveying pump (5) is connected with a feed port of the carbonization reactor (6), and a discharge port of the carbonization reactor (6) is connected with a discharge port of the second conveying pump (7).

9. The device for recovering iron oxide by utilizing red mud carbon sequestration and dealkalization according to claim 8, characterized in that the magnetic separator (10) comprises a plurality of magnetic separators with different magnetism, and the magnetism of the magnetic separator far away from the shaft kiln is larger than that of the magnetic separator near the shaft kiln.

10. The device for recovering iron oxide by utilizing red mud carbon sequestration and dealkalization according to claim 9, wherein the magnetic separator (10) comprises a weak magnetic separator, a medium magnetic separator and a strong magnetic separator, the weak magnetic separator is close to one side of the shaft kiln, the strong magnetic separator is positioned at one side far away from the shaft kiln, and the medium magnetic separator is positioned between the weak magnetic separator and the strong magnetic separator.

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