CN113479920B

CN113479920B - Aluminum ash resource utilization method

Info

Publication number: CN113479920B
Application number: CN202110761666.9A
Authority: CN
Inventors: 柯朝阳; 王志平; 杨光; 邱玉刚
Original assignee: Inner Mongolia Risheng Renewable Resources Co ltd
Current assignee: Inner Mongolia Risheng Renewable Resources Co ltd
Priority date: 2021-07-06
Filing date: 2021-07-06
Publication date: 2023-01-10
Anticipated expiration: 2041-07-06
Also published as: CN113479920A

Abstract

The invention relates to a resource utilization method of aluminum ash, which comprises the steps of firstly carrying out wet denitrification on the aluminum ash to prepare a high-aluminum material, then mixing the high-aluminum material with red mud, carbide slag and caustic soda to prepare a raw material, sintering the raw material to obtain clinker, and finally dissolving out the clinker to obtain sodium aluminate and solid slag, wherein the proportion of the high-aluminum material, the carbide slag, the red mud and the soda ash is required to meet the following requirements: A/S is more than or equal to 5, N/R is 1.03 +/-0.03, C/S is 1.5-2, F/A is 0.08-0.1. According to the invention, the processes of wet denitrification, calcification fluorine fixation and clinker sintering are combined, and the aluminum-silicon ratio in the raw material is adjusted, so that the recycling and the synergistic utilization of solid wastes such as aluminum ash, red mud and carbide slag can be realized, the solid wastes can be reduced, and the energy-saving and emission-reducing effects are good.

Description

Aluminum ash resource utilization method

Technical Field

The invention belongs to the technical field of solid waste recycling, and particularly relates to a recycling treatment method for aluminum ash.

Background

The aluminum ash is a waste of slag generated in the electrolytic aluminum or cast aluminum production process after cooling, mainly comprises a mixture of a metal aluminum simple substance, aluminum oxide and a salt flux, and is a renewable resource. Generally, aluminum ash can be classified into primary aluminum ash, secondary aluminum ash and tertiary aluminum ash according to the content of aluminum. The primary aluminum ash is grey white, is generated in the process of electrolyzing aluminum or casting and the like without adding salt flux, and is mainly composed of a mixture of aluminum and aluminum oxide, wherein the aluminum content can reach 15-70%, so the primary aluminum ash is called as white aluminum ash. Secondary aluminum ash: the salt cake is a mixture of NaCl, KCl, fluoride and 3-5% of aluminum generated after the mixture is treated and recovered by a salt bath, wherein the mixture comprises black aluminum ash, waste scraps, leftover materials and the like containing 2-18% of aluminum, salt flux, oxides and the like, and the mixture is called as a salt cake because the mixture is solidified into a block shape. Third-time aluminum ash: the waste residue left after the metal aluminum in the secondary aluminum ash is further extracted is called tertiary aluminum ash, and the existing large amount of piled up waste aluminum ash is the tertiary aluminum ash which hardly contains metal aluminum and mainly contains substances such as aluminum oxide, salt flux and the like. And aluminum and other valuable elements are recovered from the aluminum ash, so that the method has important practical significance and practical value for improving the economic benefit of enterprises and protecting the ecological environment.

There are various patented technologies to treat aluminum ash, such as: the invention patent 200610117078.7 in China for preparing sodium aluminate from waste aluminum ash proposes a process for producing solid sodium aluminate by leaching the waste aluminum ash with caustic soda, but there is no treatment method for the waste residue after dissolving out the aluminum ash, there is no treatment for the waste gas generated in the process of dissolving out the aluminum ash, and obviously the purpose of comprehensively treating the waste aluminum ash is not achieved. The invention patent CN200610048565 of China comprehensively utilizes and treats the aluminum waste residue and the waste ash, proposes that caustic soda is adopted to dissolve the aluminum waste residue and the waste ash to obtain sodium aluminate solution; the waste residue is mixed with caustic soda, lime (stone) for sintering, clinker and alkali for dissolving to obtain sodium aluminate; further extracting aluminum oxide and producing aluminum hydroxide and zeolite, but extracting aluminum and silicon step by step has high alkali consumption and complex process; no fluorine is fixed, and fluorine is mixed in the product; the nitrogen source in the aluminum ash was not utilized. Chinese patent 201611099617 a process for treating aluminum ash as resource comprises hydrolyzing aluminum ash for denitrification, calcining for defluorination, adding binder for granulation, calcining at 1000-1500 deg.C to obtain aluminum ash clinker, spraying flue gas water for defluorination, and adding lime to circulating water for fluorine fixation. Chinese patent invention 201910636033 discloses a method for efficiently recovering valuable elements from aluminum ash, which provides a method for preparing ammonium salt by hydrolyzing and denitrifying aluminum ash and absorbing ammonia acid, and a method for preparing sodium aluminate solution by hydrothermal reaction of desalted and deaminated aluminum ash and an alkali liquor autoclave, wherein fluorine is not fixed, and fluorine is mixed in the product; the hydrothermal method has low aluminum-silicon recycling rate.

When the Bayer process is adopted for producing alumina, a large amount of red mud is also generated, the red mud contains a certain amount of alumina and sodium oxide, the red mud is also a resource waste without recovery, and in addition, the red mud as a solid waste has a large influence on the environment.

In a word, at present, the treatment recovery rate of the aluminum ash in China is low, the energy consumption is large, and the research and development of recycling the industrial aluminum ash to prepare other substances have important practical significance and practical value for improving the economic benefit and protecting the ecological environment. Therefore, the method utilizes the solid wastes such as aluminum ash, red mud and the like on the basis, and has important social value and economic benefit.

Disclosure of Invention

The invention aims to provide a resource utilization method of aluminum ash aiming at the defects and shortcomings of the prior art, which recycles high-valence elements such as aluminum, nitrogen and the like in the aluminum ash to obtain byproducts such as ammonia water and the like, changes waste into valuable, improves the utilization rate of social resources, removes fluorine in the aluminum ash, performs harmless treatment, realizes the resource utilization of the aluminum ash, increases the comprehensive utilization of red mud, and is beneficial to environmental protection.

In order to achieve the purpose, the invention adopts the following technical scheme:

a resource utilization method of aluminum ash comprises the steps of firstly, carrying out wet denitrification on the aluminum ash to prepare a high-aluminum material, then mixing the high-aluminum material with red mud, carbide slag and caustic soda to prepare a raw material, sintering the raw material to obtain clinker, and finally dissolving out the clinker to obtain sodium aluminate and solid slag, wherein the ratio of the high-aluminum material, the carbide slag, the red mud and the soda ash is required to meet the following requirements: A/S is more than or equal to 5, N/R is 1.03 +/-0.03, C/S is 1.5-2, F/A is 0.08-0.1.

Furthermore, the raw material is prepared by uniformly mixing the components in the raw material according to a calculated ratio.

Furthermore, raw material coal is added in the preparation process of the raw material, and the raw material coal accounts for 3.0-5.0% (wt%) of the dry raw material based on the fixed carbon.

Further, the wet denitrification step S1 is catalytic denitrification: adding the aluminum ash into a water-injected denitrification reaction tank, maintaining the alkali concentration in water to be 1-5wt%, and carrying out alkali catalytic hydrolysis on aluminum nitride in the aluminum ash to release ammonia gas for denitrification so as to form denitrification slurry; and carrying out solid-liquid separation and washing on the denitrification slurry to form a high-aluminum material and denitrification liquid.

Further, the method comprises a step S2 of calcifying and fixing fluorine, wherein the calcified and fixed fluorine is carried out on the denitrified liquid formed after the aluminum ash is hydrolyzed and denitrified so as to solidify the fluoride in the aluminum ash.

Further, the raw material is prepared as the step S3: adding the high-alumina material into a ball mill, proportionally mixing the carbide slag, the red mud, the soda ash and the raw material coal, stirring, grinding and homogenizing to form the raw material with solid content meeting the requirement.

Further, the clinker sintering step is a step S4: and spraying the raw materials from the tail of the rotary kiln, spraying coal powder to the head of the rotary kiln, controlling the sintering temperature to be 1000-1250 ℃, and sintering for 10-60 minutes to obtain the clinker after sintering.

Further, sodium aluminate generation is a process S5: the clinker is crushed and ground, the clinker is dissolved out to obtain dissolved slurry, then crude sodium aluminate liquid and solid slag are obtained through sedimentation and solid-liquid separation, and the crude sodium aluminate liquid is prepared into refined sodium aluminate liquid through a vertical leaf filter.

Further, the aluminum ash is secondary aluminum ash, and comprises the following components in percentage by mass: al (aluminum) ₂ O ₃ 38-50 percent of AlN, 25-35 percent of MgAl ₂ O ₄ 1-10% of Fe ₂ O ₃ 1-3% of SiO ₂ 1-7% of CaF ₂ 1-3 percent of NaF, 1-5 percent of NaF and 0.5-1.5 percent of KF.

Further, the recovery rate of nitrogen in the aluminum ash is more than 98%, and the recovery rate of alumina in solid waste consisting of the aluminum ash and red mud is more than 93%.

Compared with the prior art, the invention has the following beneficial effects:

1) According to the method, the wet denitrification, normal-temperature calcification fluoride fixation, clinker sintering and sodium aluminate preparation are organically combined to prepare the sodium aluminate solution, meanwhile, the byproduct is low-concentration ammonia water, and wastewater in the process is recycled, so that the harmless treatment of solid wastes such as aluminum ash, red mud and carbide slag is realized, and the resource synergistic utilization of the solid wastes such as the aluminum ash, the red mud and the carbide slag is realized.

2) The method combines the wet denitrification and normal-temperature calcification fluorine fixation, has mild and safe reaction conditions, easy process control, simple equipment and less investment, does not generate the problems of incomplete denitrification caused by direct high-temperature calcination denitrification and fluorine fixation of aluminum ash and dangerous fluorine waste pollution caused by subsequent clinker sintering because fluorine compounds leak into the atmosphere, does not generate secondary pollution, meets the production requirements of industrialized green factories, and is suitable for industrialized popularization and application.

3) In the process of the invention, three wastes are not generated in the harmless treatment process, no waste gas is discharged, the waste water generated in the process of the process treatment can be recycled in a system, no waste water is discharged, and dangerous waste fluorine is converted into stable calcium fluoride through solidification, thereby avoiding the pollution of fluorine to the environment and the atmosphere.

4) The invention firstly denitrifies and fixes fluorine to extract nitrogen resources, and then sinters and recycles the resources such as aluminum and the like in the solid wastes such as aluminum ash and the like, the efficiency of denitrogenation and fluorine fixation is high and thorough, the content of nitrogen and fluorine in the product sodium aluminate is low, and the content of impurity nitrogen, chlorine and fluorine in the product sodium aluminate solution is lower than 0.01 percent. In addition, the wet denitrification method is adopted for the aluminum ash, so that the problem of environmental influence caused by emission of ammonia gas in the production process due to hydrolysis of aluminum nitride in the aluminum ash when the aluminum ash is directly mixed with red mud and other solid wastes can be solved.

5) In the invention, high-valence elements such as aluminum, nitrogen and the like in the solid waste are efficiently utilized, wherein the recovery rate of nitrogen in aluminum ash is more than 98%, and the recovery rate of alumina in the solid waste consisting of the aluminum ash and red mud is more than 93%.

6) The invention optimizes the recycling of the waste heat of the flue gas generated by sintering the clinker, on one hand, the flue gas automatically returns to the kiln tail to dry and dehydrate the materials entering the rotary kiln, and on the other hand, the waste heat flue gas heats the hydrolysis medium for catalytic denitrification, thereby improving the heat utilization efficiency of the whole process system, saving the steam consumption in the process and having better energy-saving effect.

7) The invention adds proper amount of raw coal into raw material, which can play the role of sulfur discharge of aluminum ash. Carbon in coal can form reducing atmosphere (CO) during sintering, and Na is added at 700-800 deg.C ₂ SO ₄ Reduced to Na ₂ S, mixing Fe ₂ O ₃ Reduced to FeO. A part of Na ₂ S enters into the solution in the subsequent clinker dissolving stage, thereby achieving the purpose of removing sulfur in the aluminum ash. Another part of Na ₂ S can also react with FeO in the sintering process to generate FeS, and the FeS can enter the red mud so as to achieve the effect of sulfur removal of aluminum ash.

8) The method can utilize red mud solid waste and aluminum ash in the ordinary Bayer process, solves the problem of difficult proportioning caused by high red mud iron content in the traditional sintering process, and can promote large-scale recycling and cooperative utilization of the solid waste such as the aluminum ash, the red mud, the carbide slag and the like, thereby realizing recycling of the solid waste.

9) The invention adopts the high aluminum-silicon ratio to prepare the raw material, can reduce the iron-aluminum ratio in the raw material, improve the conversion ratio of the clinker and improve the productivity of the product sodium aluminate crude liquid, thereby reducing the energy consumption of the system, reducing the unit energy consumption of the product sodium aluminate crude liquid and reducing the carbon emission of the system. Meanwhile, the yield of the calcium silicate slag in the system can be reduced, so that the recycling and reduction of solid wastes are realized, the energy conservation and emission reduction are realized, the environmental protection benefit is obvious, and the clean production is realized.

Drawings

FIG. 1 is a schematic view of a process flow for resource utilization of aluminum ash.

Detailed Description

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 will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can also be derived from them without inventive effort.

FIG. 1 is a schematic view of a process flow for resource utilization of aluminum ash. As shown in fig. 1, the invention provides a resource utilization method of aluminum ash, which comprises the steps of firstly performing wet denitrification on aluminum ash to prepare a high-aluminum material, then mixing the high-aluminum material with red mud, carbide slag and caustic soda to prepare a raw material, sintering the raw material to obtain clinker, and finally dissolving out the clinker to obtain sodium aluminate and solid slag, wherein the ratio of the high-aluminum material to the carbide slag to the red mud to the soda ash is required to meet the following requirements: A/S is more than or equal to 5, N/R is 1.03 +/-0.03, C/S is 1.5-2, and F/A is 0.08-0.1.

Furthermore, the water content of the raw material is 38-42% (wt%).

Further, the wet denitrification comprises the following steps: and adding the aluminum ash into a water-injected denitrification reaction tank for hydrolysis denitrification.

Further, the wet denitrification is a catalytic denitrification in the step S1: adding the aluminum ash into a water-injected denitrification reaction tank, maintaining the alkali concentration in water to be 1-5wt%, and carrying out alkali catalytic hydrolysis on aluminum nitride in the aluminum ash to release ammonia gas for denitrification so as to form denitrification slurry; and carrying out solid-liquid separation and washing on the denitrification slurry to form a high-aluminum material and denitrification liquid.

Further, the aluminum ash is secondary aluminum ash, and the aluminum ash comprises the following components in percentage by mass: al (Al) ₂ O ₃ 38-50 percent of AlN, 25-35 percent of MgAl ₂ O ₄ 1-10% of Fe ₂ O ₃ 1-3% of SiO ₂ 1-7% of CaF ₂ 1-3 percent of NaF, 1-5 percent of NaF and 0.5-1.5 percent of KF.

Further, the fluoride may be sodium fluoride and potassium fluoride, and in the S1 catalytic denitrification process, the sodium fluoride and the potassium fluoride are dissolved into the denitrification slurry.

Further, the S2 calcification fluorine fixation is that a fluorine fixation reaction tank receives the denitrified liquid and then pumps a fluorine fixation agent, and the fluorine fixation agent treats the denitrified liquid at normal temperature to solidify fluoride in the denitrified liquid; the fluorine fixing agent is calcium hydroxide or calcium chloride; preferably, the fluorine-fixing agent is calcium hydroxide.

Further, the raw material is prepared as the step S3: adding the high-alumina material into a ball mill, proportionally mixing the carbide slag, the red mud, the soda ash and the raw material coal, stirring, grinding and homogenizing to form uniform raw material.

Further, clinker sintering is a step S4: and spraying the raw materials from the tail of the rotary kiln, spraying coal powder to the head of the rotary kiln, controlling the sintering temperature to be 1000-1250 ℃, and sintering for 10-60 minutes to obtain the clinker after sintering.

Further, sodium aluminate generation is a step S5 of sodium aluminate preparation: the clinker is crushed and ground, the clinker is dissolved out to obtain dissolved slurry, then crude sodium aluminate liquid and solid slag are obtained through sedimentation and solid-liquid separation, and the crude sodium aluminate liquid is prepared into refined sodium aluminate liquid through a vertical leaf filter.

Further, in the S1 catalytic denitrification process, the liquid-solid ratio in the denitrification reaction tank is controlled to be 5-8:1.

further, the fluorine fixing agent is carbide slag; the carbide slag comprises the following components in percentage by mass: 56.8 to 65 percent of CaO and Al ₂ O ₃ 1.25-4% of SiO ₂ 2.5-7.5% of Fe ₂ O ₃ 0.2 to 0.96 percent.

Further, the secondary aluminum ash is added into the denitrification reaction tank to carry out hydrolysis on the aluminum nitride, the hydrolysis temperature is 70-100 ℃, the hydrolysis is preferably 90 ℃, and the hydrolysis reaction time is 1-3 hours, preferably 2 hours.

Further, firstly adding water into the denitrification reaction tank, then adding NaOH to adjust the alkali concentration to 2-3wt%, then adding the secondary aluminum ash, and heating to the hydrolysis temperature for hydrolysis.

Furthermore, the denitrification reaction tank is of a sealing structure and is sequentially communicated with an ammonia absorption tower, an induced draft fan and a chimney through a sealing pipeline.

Further, in the step of catalytic denitrification in the S1, starting an induced draft fan and an ammonia gas absorption tower which are connected with the denitrification reaction tank, introducing ammonia gas into the ammonia gas absorption tower through the induced draft fan, forming low-concentration ammonia water and residual gas in the ammonia gas absorption tower through spray water, and sending the low-concentration ammonia water into an ammonia water storage tank for temporary storage for denitrification treatment; the residual gas is discharged to the atmosphere.

Further, in the step of S1 catalytic denitrification, the low-concentration ammonia water is formed in the ammonia gas absorption tower by water mist spraying and filler absorption; and the residual gas is purified and discharged to the atmosphere after reaching the standard.

Further, in the S1 catalytic denitrification step, superheated steam is supplied into the denitrification reactor to supplement heat required for the denitrification reaction, and the saturated steam has a temperature of 159 ℃ and a pressure of 0.6MPa.

Further, in the S1 catalytic denitrification step, the low-concentration ammonia water formed in the ammonia gas absorption tower is controlled, and the shower water is normal-temperature water, preferably low-temperature water.

Further, in the S1 catalytic denitrification process, the content of chloride ions in the liquid phase entering the denitrification groove is monitored, when the content of the chloride ions is higher, the entering amount of the liquid phase is stopped or reduced, and the liquid phase is subjected to chloride ion removal treatment; the dechlorination treatment comprises membrane permeation separation.

Further, the denitrification slurry is pumped into a box-type filter press through a slurry pump to be subjected to solid-liquid separation and washing to form a high-aluminum material and a denitrification liquid, the high-aluminum material is fed into a raw material preparation process of S3, and the denitrification liquid enters a fluorine fixing reaction tank of the S2 calcification fluorine fixing process to fix fluorine.

Further, in the step of calcifying and fixing fluorine in S2, the denitrified solution is flowed into the fluorine fixing reaction tank, and then the calcium hydroxide or calcium chloride is added, and the calcium hydroxide or calcium chloride and sodium fluoride and potassium fluoride in the denitrified solution undergo a fluorine fixing reaction at normal temperature to generate calcium fluoride.

Further, in the step of S2 calcified fluorine fixation, pumping the solid-fluorine reaction liquid generated after the fluorine fixation reaction into a chamber filter press by using a slurry pump for solid-liquid separation and washing to form calcium fluoride and a liquid phase, wherein the liquid phase enters the denitrification groove of the step of S1 catalytic denitrification for recycling, and the calcium fluoride is sent into a solid waste storage yard.

Further, the high-aluminum material comprises the following components in percentage by mass: al (Al) ₂ O ₃ 60.15-73.29% of MgAl ₂ O ₄ 2.28-7.95% of Fe ₂ O ₃ 0.87-2.38% of SiO ₂ 2.28 to 5.56 percent of CaF ₂ 0.78-2.39%, water content of 17-21.88%, and Na ₂ 0.75-2.3% of O and 1.6-2.28% of the rest.

Further, the carbide slag comprises the following components in percentage by mass: 56.8 to 65 percent of CaO and Al ₂ O ₃ 1.25-4% of SiO ₂ 2.5-7.5% of Fe ₂ O ₃ Accounting for 0.2 to 0.96 percent.

Further, the red mud comprises the following components in percentage by mass: al (Al) ₂ O ₃ 19.5-30.48% of SiO ₂ 11.58 to 23.76 percent of Fe ₂ O ₃ 19.2 to 38.24 percent of Na ₂ O accounts for 5.31 to 11.48 percent.

Further, the amount of sodium carbonate added can be reduced after the industrial production cycle, and the raw meal is prepared by adding the circulating mother liquor.

Furthermore, desiliconized silicon slag can be added into the raw material to prepare the raw material in industrial production.

Further, the carbide slag comprises 65 percent (wt%) of calcium oxide and Al ₂ O ₃ 0.25% (wt%) SiO ₂ 7.9% (wt%) Fe ₂ O ₃ 0.96% (wt%).

Further, in the step of preparing the raw material S3, the step of wet grinding the raw material in an ore pulp ball mill to obtain homogenized raw material, wherein the ball milling time is 15-60min, the abrasive particle size is less than or equal to 50mm, and the ball milling temperature is 60-80 ℃.

Further, in the S4 clinker sintering process, the rotary kiln is divided into a drying zone, a preheating zone, a decomposition zone, a sintering zone and a cooling zone in sequence according to functions from the kiln tail to the kiln head, the temperatures of the zones are 120 ℃,120-600 ℃,600-1000 ℃,1000-1300 ℃,800-1000 ℃, the outlet temperature of the cooling zone is 700-800 ℃, and the hot air of the cooling zone returns to the drying zone through a pipeline; the pressure of the spray gun at the kiln head is 1.8-2.2MPa, and the pressure of the kiln tail is more than or equal to-500 Pa.

Further, in the S4 clinker sintering process, the coal dust is sprayed into the kiln head of the rotary kiln, wherein H in the coal dust ₂ O is less than or equal to 2 percent (wt percent), and the fineness of the coal powder is less than or equal to 14 percent (160 # sieve residue).

Further, in the S4 clinker sintering process, the amount of coal injected into the pulverized coal is determined according to the raw material feeding amount and the moisture in the raw material so as to maintain the sintering temperature.

Further, in the step of sintering the clinker in the step S4, the process further includes performing electric dust removal treatment on flue gas generated by the rotary kiln in calcining the raw meal, recovering waste heat in the flue gas, and using the flue gas to heat the raw meal in the step S3 of preparing the raw meal or to heat water in the denitrification reaction tank in the step S1 of catalytic denitrification.

Further, in the preparation process of the S5 sodium aluminate solution, a dissolution mill is adopted, the first-stage dissolution temperature is 70-80 ℃, the dissolution time is 20-40 minutes, the grinding solid-to-liquid ratio is 3.5 +/-0.5, the temperature of the adjustment liquid is more than 70 ℃, the second-stage dissolution liquid-to-solid ratio is 2 +/-0.5, and the bottom flow L/S of the dissolution settling tank is 2.5-4.5, so that the dissolution slurry is obtained.

Further, in the step of preparing sodium aluminate S5, the clinker is crushed and ground to a granularity of not more than 10 mm.

Further, in the S5 sodium aluminate production process, the vertical leaf filter filters suspended solids.

Further, in the S5 sodium aluminate preparation procedure, the solid slag is calcium-silicon slag and is sent to a fluorine-fixing storage yard.

Further, in the S5 sodium aluminate preparation process, the sodium aluminate green liquor contains NaAl0H ₄ NaOH and Na ₂ CO ₃ According to Al ₂ O ₃ And calculating the total alkali, wherein the Al in the sodium aluminate crude liquid ₂ O ₃ The content is 100-170 g/l, and the total alkali content is105-170 g/l.

The present invention is described in detail below with reference to the accompanying drawings and specific embodiments, which are not described in detail herein, but the present invention is not limited to the following embodiments.

Aluminum ash and other raw materials

The solid waste raw materials such as aluminum ash, red mud, carbide slag and the like used in the invention are all waste materials from peripheral industrial parks. Wherein:

the aluminum ash is secondary aluminum ash from an electrolytic aluminum factory and is transported to an aluminum ash temporary storage warehouse of a company, and the warehouse construction standard is constructed according to the requirement of aluminum ash storage. Reach the standards of water-proof, moisture-proof and explosion-proof. The aluminum ash is secondary aluminum ash and comprises the following components in percentage by mass: al (Al) ₂ O ₃ 38-50 percent of AlN, 25-35 percent of MgAl ₂ O ₄ 1-10% of Fe ₂ O ₃ 1-3% of SiO ₂ 1-7% of CaF ₂ 1 to 3 percent of NaF, 1 to 5 percent of NaF and 0.5 to 1.5 percent of KF.

The red mud comes from an alumina plant, and the red mud comprises the following components in percentage by mass: al (aluminum) ₂ O ₃ 19.5-30.48% of SiO ₂ 11.58 to 23.76 percent of Fe ₂ O ₃ 19.2 to 38.24 percent of Na ₂ O accounts for 5.31 to 11.48 percent.

The carbide slag is waste slag generated in PVC production in a certain chemical plant, and comprises the following components in percentage by mass: 56.8 to 65 percent of CaO and Al ₂ O ₃ 1.25-4% of SiO ₂ 2.5-7.5% of Fe ₂ O ₃ 0.2 to 0.96 percent.

Coal: anthracite coal with low sulfur content, H in coal ₂ O is less than or equal to 2 percent (wt percent), and the fineness of the coal powder (160 # sieve residue) is less than or equal to 14 percent.

The soda ash and the sodium hydroxide in the invention are from purchased chemical and commercial grade raw materials.

Example 1

The aluminum ash is treated by adopting the aluminum ash resource utilization process flow shown in figure 1. The method specifically comprises the following steps:

(1) S1 aluminum ash catalytic denitrification

In the embodiment, the aluminum ash is secondary aluminum ash, nitrogen in the aluminum ash is removed in a catalytic denitrification mode, and the aluminum ash is recycled.

In a denitrification reaction tank with stirring, firstly adding water, then adding alkali (NaOH) to adjust the alkali concentration of the aqueous solution in the denitrification reaction tank to be 2-3wt%, then adding aluminum ash, and controlling the liquid-solid ratio in the denitrification reaction tank to be 5-8:1. introducing superheated steam with the temperature of 250 ℃ and the pressure of 4 kilograms into the aqueous solution in the denitrification reaction tank, heating the aqueous solution in the denitrification reaction tank to 90 ℃, keeping the temperature, stirring and reacting for 2 hours. In the process, aluminum nitride (AlN) in the aluminum ash undergoes a hydrolysis reaction, and the reaction principle is as follows:

AlN+3H ₂ O＝Al(OH) ₃ ↓+NH ₃ ×) @. The aluminum nitride in the aluminum ash undergoes hydrolysis reaction to release ammonia gas.

And during the hydrolysis reaction, opening an ammonia absorption tower and an induced draft fan, introducing ammonia into the ammonia absorption tower through the induced draft fan, wherein the ammonia absorption tower is a packed tower with a spray function. The ammonia gas entering the absorption tower absorbs water mist sprayed from the top of the absorption tower and ammonia gas rising from the bottom of the tower in the tower, forms low-concentration ammonia water on the surface of the filler, is sent into an ammonia water storage tank for temporary storage, then is pumped into a boiler room for denitration, and the ammonia gas is purified to reach the standard and then is discharged to the atmosphere.

In this embodiment, the spray water is normal temperature water, preferably low temperature water, and is absorbed by three or more stages of towers, the spray water enters the tower from the last stage of tower, and the ammonia gas enters the tower from the 1 st stage of tower, and the ammonia gas is absorbed in a countercurrent manner.

After the denitrification reaction is finished, the denitrification slurry is pumped into a box type filter press through a slurry pump to be subjected to solid-liquid separation and washing to form a solid high-aluminum material and denitrification liquid, in the process, the high-aluminum material is washed, wherein the solid high-aluminum material containing water is fed into an ore pulp grinding process, valuable element ingredients such as aluminum silicon and the like are dissolved out in an ore pulp ball mill, and the denitrification liquid enters a calcification fluorine fixing process to fix fluorine.

After the aluminum ash is treated by the catalytic denitrification process, the formed solid-phase high-aluminum material comprises the following components in percentage by mass:

Al ₂ O ₃ 68.12% (wt%) MgAl ₂ O ₄ 6.31% (wt%) Fe ₂ O ₃ 1.05% (wt%) of SiO ₂ 3.97% (wt%) CaF ₂ 0.86% (wt%) of Na ₂ O was 0.85%, the water content was 17.39% (wt%), and the others were 1.45% (wt%). Nitrogen and fluorine in the aluminum ash are basically removed, and the products sintered by the clinker in the subsequent process are ensured not to contain nitrogen and fluorine impurities.

(2) S2 calcified fluorine fixation

The denitrogenation liquid after the notes denitrogenation in solid fluorine reaction tank adds solid fluorine agent carbide slag thick liquid, and calcium oxide in the carbide slag thick liquid and sodium fluoride, potassium fluoride in the denitrogenation liquid react at normal atmospheric temperature and generate calcium fluoride, and this process need not heat in addition, the reaction principle:

2NaF+CaO+H ₂ O＝CaF ₂ +2NaOH,2KF+CaO+H ₂ O＝CaF ₂ +2KOH

and after the fluorine fixing reaction is finished, pumping the fluorine fixing reaction liquid into a chamber type filter press by using a slurry pump for solid-liquid separation and washing to form calcium fluoride and a liquid phase, washing the calcium fluoride with water in the process, enabling the liquid phase to enter a denitrification groove of a catalytic denitrification process for recycling, and sending the calcium fluoride into a solid waste storage yard.

Because the hot water washing of the aluminum ash in the aluminum ash catalytic denitrification process can dissolve out chloride ions in the aluminum ash to form primary salts such as NaCl and KCl, and the accumulation of the chloride ions in the catalytic denitrification process can have adverse effects on the process, the chloride ions in the liquid phase need to be monitored, and especially when calcium chloride is used as a fluorine fixing agent, a large amount of primary salts such as NaCl and KCl can be generated, and in order to prevent the content of the chloride ions from being too high, the NaCl and KCl in the aluminum ash can be regularly washed away by filtering.

In the embodiment, in the catalytic denitrification process, the content of chloride ions in the liquid phase entering the denitrification tank is monitored on line, when the content of the chloride ions is higher, the entering amount of the liquid phase is stopped or reduced, and the liquid phase is subjected to chloride ion removal treatment; the dechlorination treatment comprises membrane permeation separation, evaporative crystallization and primary salt removal.

(3) S3 preparation of raw material

Adding the high-alumina material into a ball mill, and adding carbide slag, red mud, soda ash and raw coal to prepare raw materials, wherein:

the carbide slag comprises the following components in percentage by mass: calcium oxide accounts for 64.75%, aluminum oxide accounts for 1.95%, silicon oxide accounts for 3.5%, ferric oxide accounts for 0.96%, and the other accounts for 3.08%; loss on ignition: 25.76 percent;

the mass percentage of the red mud is Al ₂ O ₃ 20.7%, S iO ₂ 19.88% of Fe ₂ O ₃ 30.2% of Na ₂ 9.82 percent of O, 17.4 percent of water and 2 percent of calcium oxide.

According to the raw materials: the ratio of aluminum to silicon A/S =7, the ratio of alkali N/R is 1.04, the ratio of calcium C/S is 2.0, the ratio of iron to aluminum F/A is 0.098, the raw material coal is 4.5% (wt%), the fineness is plus 120# < 14%, and the water content is 38-42% (wt%), and raw materials are prepared. The specific preparation method takes the aluminum-silicon ratio of the raw material as an example to calculate:

assuming Al in the green stock ₂ O ₃ With SiO ₂ All come from high-alumina materials and red mud (not considering the introduction of carbide slag, after the calculation of subsequent correction), and the total material addition amount of the high-alumina materials and the red mud is 100g. If the adding amount of the high-aluminum material is x g, the adding amount of the red mud ash is (100-x) g. Al in high-alumina material ₂ O ₃ 68.12% of SiO ₂ The content is 3.97%; al in red mud ₂ O ₃ 20.7% of SiO ₂ The content was 19.88%.

When the Al/Si ratio is set to 7.0, the adding amount of the aluminum material is 74.602 g, and the adding amount of the red mud is 25.398 g.

Setting the alkali ratio to be 1.04, and adding 62.9716 g of soda ash; setting the calcium ratio to be 2.0, and adding 22.3099 g of carbide slag; at this time, the actual ratio of aluminum to silicon in the mixture is 6.4288; the alkali ratio is 1.03; the calcium ratio is 1.95; the iron to aluminum ratio was 0.098. The mixture ratio of the raw materials is basically similar to that of the raw materials in the embodiment.

In this embodiment, the initial required materials and the mass percentage composition are as follows: 40.52%, sodium carbonate: 34.2%, carbide slag: 11.48%, red mud: 13.8%, raw coal: 4.5%, the addition of sodium carbonate can be reduced after the circulation of industrial production, and the raw material can be prepared by adding the circulating mother liquor. The concentration of the sodium aluminate is adjusted according to the circulating mother liquor generated by different purposes of the crude sodium aluminate solution. In addition, desiliconized silicon slag can be added into the raw material to prepare the raw material in industrial production.

Preparing raw materials, stirring, feeding into an ore pulp ball mill for grinding, homogenizing, and dissolving out to obtain qualified raw materials.

In this example, a raw material formed by high alumina material, carbide slag, red mud, soda ash and raw coal is wet-milled in a pulp ball mill to obtain a homogenized raw material, the moisture content of the raw material is controlled to be 38-42% (wt%), and the operation conditions of the pulp ball mill are as follows: a one-stage open-circuit ore grinding process is adopted, and a three-bin tube mill is selected. Grinding high-alumina material, soda ash, carbon content mother liquor, red mud and carbide slag into raw material slurry according to the above raw material slurry preparation proportion, wherein the ball milling time is 15-60min, the grinding material granularity (120 # sieve residue) is less than or equal to 14%, and the ball milling temperature is 60-80 ℃. A raw meal with a suitable water content of 38% is finally formed. In the embodiment, the carbon mother liquor formed in the process of preparing the aluminum hydroxide by the carbon separation method can be utilized to recycle the sodium carbonate, and the circulating mother liquor is added to prepare the raw material.

(4) S4 clinker sintering

Atomizing and spraying the raw materials from the kiln tail of the rotary kiln, spraying finished coal powder to the kiln head of the rotary kiln, controlling the sintering temperature to be 1050 ℃ and the sintering time to be 15 minutes, and cooling to obtain clinker.

In the embodiment, the rotary kiln is divided into a drying zone, a preheating zone, a decomposing zone, a sintering zone and a cooling zone from the kiln tail to the kiln head according to functions in sequence, the temperature of each zone is 120 ℃,120-600 ℃,600-1000 ℃,1000-1300 ℃,800-1000 ℃, the outlet temperature of the cooling zone is 700-800 ℃, and hot air of the cooling zone returns to the drying zone through a pipeline to rapidly dehydrate and dry raw material slurry entering the rotary kiln; the pressure of the kiln head spray gun is 1.8-2.2MPa, and the pressure of the kiln tail is more than or equal to-500 PaMPa.

In this embodiment, finished coal powder, preferably coal with low sulfur content, H in the coal powder, is injected into the kiln head of the rotary kiln ₂ O is less than or equal to 2 percent (wt percent), and the fineness of the coal powder (160 # sieve residue) is less than or equal to 14 percent. Sintering in clinkerIn the working procedure, the coal quantity of the coal powder is determined by keeping the sintering temperature according to the raw material feeding quantity and the moisture in the raw material, and the coal quantity is controlled to ensure that the clinker is well sintered but not over-sintered.

(5) Preparation of sodium aluminate

And (3) putting the clinker into a ball mill, crushing and grinding the clinker until the granularity is not more than 10 mm, adding alkali liquor to dissolve the clinker to obtain dissolved slurry, settling, performing solid-liquid separation and water washing to obtain sodium aluminate crude liquid and solid slag, wherein the solid slag is calcium-silicon slag, and sending the calcium-silicon slag into a cement plant or a solid waste storage yard. Washing liquid formed after washing the solid slag by water can be sent to dissolve out clinker for recycling.

In this example, a dissolution mill was used, the first stage dissolution temperature was 70-80 ℃, the dissolution time was 20-40 minutes, the solid-to-liquid ratio of the milling was 3.5 ± 0.5, the temperature of the conditioning solution was >70 ℃, the solid-to-liquid ratio of the second stage dissolution was 2 ± 0.5, and the bottom flow L/S of the dissolution settling tank was 2.5-4.5, to obtain a dissolution slurry.

In this embodiment, a qualified crude liquid product of sodium aluminate is finally prepared through catalytic denitrification of aluminum ash, calcification fluorine fixation, raw material preparation, clinker sintering and sodium aluminate preparation, wherein the crude liquid of sodium aluminate contains NaAl0H ₄ NaOH and Na ₂ CO ₃ According to Al ₂ O ₃ And the Al in the sodium aluminate solution is calculated according to total alkali ₂ O ₃ The content was 110 g/l and the total base content was 105 g/l. The recovery rate of nitrogen in the aluminum ash is more than 98%, and the recovery rate of alumina in the solid waste consisting of the aluminum ash and red mud is more than 93%. No nitrogen or fluorine is detected in the product. Wherein, after the nitrogen is removed, the by-product low-concentration ammonia water is recovered, and the fluorine is solidified to form the calcium fluoride with stable property. In the whole production process, no waste gas is discharged, waste water generated in the system is recovered through evaporation and is used for washing and batching for solid-liquid separation in the process, and washing liquid after washing can also be used for dissolving out clinker, so that recycling in the system is realized, no waste water is discharged, and harmless treatment of solid waste aluminum ash is realized, and the valuable elements such as aluminum, nitrogen and the like are recycled. The sintering flue gas waste heat in the system is recycled, and the whole system realizes clean production。

Example 2

The aluminum ash is treated by adopting the aluminum ash resource utilization process flow shown in figure 1. The difference from the embodiment 1 is mainly as follows:

(1) S1 aluminum ash catalytic denitrification

Adjusting the alkali concentration of the aqueous solution in the denitrification reaction tank to be 1wt%, then adding secondary aluminum ash, and controlling the liquid-solid ratio in the denitrification reaction tank to be 6:1. the method comprises the following steps of recovering the waste heat of flue gas generated by a rotary kiln in the subsequent S4 clinker sintering process, directly heating the aqueous solution in a denitrification reaction tank through a heat exchange tube, monitoring the temperature rise condition of the aqueous solution in the denitrification reaction tank on line, supplementing superheated steam with the temperature of 250 ℃ and the pressure of 4 kilograms into the aqueous solution in the denitrification reaction tank, heating the aqueous solution in the denitrification reaction tank to 90 ℃, keeping the temperature, stirring and reacting for 2 hours. Aluminum nitride (AlN) in the aluminum ash is hydrolyzed to remove nitrogen and release ammonia gas.

After the secondary aluminum ash is treated by the catalytic denitrification process, the water content of the formed high-aluminum material is 19%, nitrogen and fluorine in the aluminum ash are basically removed, and the product fired by clinker in the subsequent process is ensured to contain no nitrogen and fluorine impurities.

(2) S3 preparation of raw material

Adding high-alumina material containing 19% of water into a ball mill, stirring, feeding into an ore pulp ball mill for grinding, homogenizing, dissolving out and batching, wherein the water content of the raw material slurry is 42%.

(3) S4 clinker sintering

Atomizing and spraying the raw material slurry from the kiln tail of the rotary kiln, spraying coal powder to the kiln head of the rotary kiln, controlling the sintering temperature to be 1050 ℃ and the sintering time to be 20 minutes, and cooling to obtain clinker.

(4) Preparation of sodium aluminate

And removing suspended matters in the coarse sodium aluminate solution obtained after the clinker is dissolved out by a vertical leaf filter to prepare the fine sodium aluminate solution.

In this embodiment, a qualified refined sodium aluminate solution product is finally prepared through aluminum ash catalytic denitrification, calcified fluorine fixation, raw material preparation, clinker sintering and sodium aluminate preparation, wherein a crude refined sodium aluminate solution contains NaAl0H ₄ NaOH and Na ₂ CO ₃ According to Al ₂ O ₃ And Al in the sodium aluminate solution calculated by total alkali ₂ O ₃ The content was 112 g/l and the total base content was 127 g/l. The recovery rate of nitrogen in the aluminum ash is more than 98 percent, and the recovery rate of alumina in the solid waste consisting of the aluminum ash and red mud is more than 93 percent. . The product can not detect nitrogen and fluorine basically. The sintering flue gas waste heat in the system is also recycled, and the whole system realizes clean production.

Example 3

(1) S3, preparing a raw material, namely adding a high-alumina material containing 21% of water into a ball mill, stirring, feeding into an ore pulp ball mill for grinding, homogenizing, dissolving out and batching.

(2) S4, clinker sintering, namely spraying the raw material slurry from the tail of the rotary kiln, spraying coal powder to the head of the rotary kiln, controlling the sintering temperature to 1050 ℃ and the sintering time to 15 minutes, and cooling to obtain clinker.

(3) Preparing sodium aluminate by catalytic denitrification of aluminum ash, calcification fluorine fixation, preparation of raw material, sintering of clinker and preparation of sodium aluminate to finally prepare qualified sodium aluminate crude liquid product, wherein the sodium aluminate crude liquid contains NaAl0H ₄ NaOH and Na ₂ CO ₃ According to Al ₂ O ₃ And the total alkali, the Al in the sodium aluminate solution ₂ O ₃ The content was 100 g/l and the total base content was 124 g/l. The recovery rate of nitrogen in the aluminum ash is more than 98 percent, and the recovery rate of alumina in the solid waste consisting of the aluminum ash and red mud is more than 93 percent. . No nitrogen or fluorine is detected in the product. The sintering flue gas waste heat in the system is also recycled, and the whole system realizes clean production.

Example 4

The aluminum ash is treated by adopting the aluminum ash resource utilization process flow shown in figure 1. The difference from example 1 is that: in the step 2, calcification fluorine fixing is carried out, after the fluorine fixing reaction is finished, fluorine fixing reaction liquid is pumped into a box type filter press by a slurry pump to carry out solid-liquid separation to form calcium fluoride and a liquid phase, in the process, the calcium fluoride is washed by water, and the liquid phase enters a denitrification groove of the step 1 of catalytic denitrification for recycling.

The recovery rate of nitrogen in aluminum ash of the finally prepared sodium aluminate solution product is more than 98%, and the recovery rate of alumina in solid waste consisting of the aluminum ash and red mud is more than 93%. Although no waste gas is discharged in the whole production process, the waste water generated in the system is recovered through evaporation, the internal recycling of the system is realized, no waste water is discharged, and the solid waste aluminum ash realizes harmless treatment and resource utilization of valuable elements such as nitrogen, aluminum and the like. However, since the chlorine element in the aluminum ash is not monitored and is timely washed away in the S1 catalytic denitrification process, the accumulation of primary salts such as NaCl and KCl generated from chlorine eventually causes the corrosion of denitrification equipment.

Example 5

The aluminum ash is treated by adopting the aluminum ash resource utilization process flow shown in figure 1. The difference from example 1 is that: in the step S3, the raw materials of the high-alumina materials, the carbide slag, the red mud, the soda ash and the raw coal which are prepared in the preparation tank are stirred, homogenized and proportioned only in the preparation tank, and are not sent to an ore pulp ball mill for grinding to prepare the raw materials. The final product of the crude liquid of sodium aluminate prepared by the embodiment, wherein the crude liquid of sodium aluminate contains NaAl0H ₄ NaOH and Na ₂ CO ₃ According to Al ₂ O ₃ And the Al in the sodium aluminate solution is calculated by total alkali ₂ O ₃ The content was 98 g/l and the total base content was 110 g/l. The recovery rate of nitrogen in the aluminum ash is more than 97%, and the recovery rate of alumina in the solid waste consisting of the aluminum ash and red mud is more than 89%. . No nitrogen or fluorine can be detected in the product. The solid waste aluminum ash realizes harmless treatment and obtains resource utilization of valuable elements such as nitrogen, aluminum and the like, but the aluminum recovery rate is reduced, which shows that the raw material slurry formed by mixing and feeding the raw material in the raw material preparation process into the ore pulp ball mill for full grinding can ensure that the aluminum element in the high-aluminum material is fully dissolved into the raw material, and the sintering, dissolution and recovery of the subsequent clinker are easier.

Comparative example 1

The method is characterized in that the aluminum ash is subjected to resource utilization by referring to the prior art, specifically, the aluminum ash is subjected to hydrolytic denitrification and solid-liquid separation, a denitrification liquid is subjected to calcification fluorine fixation, a separated high-aluminum material is added with sodium carbonate and then directly sent into an ore pulp ball mill for full grinding to form a high-aluminum material raw material, the raw material is sprayed from the tail of a rotary kiln, coal powder is sprayed into the head of the rotary kiln, and sintering is carried out at the sintering temperature of 1000-1100 ℃.

The difference from example 1 is that: in this comparative example, because the high-alumina material is not added with the carbide slag and the red mud, that is, the formula of the raw material is different from that of example 1, the iron-aluminum ratio in the raw material is too low, the sintering alkali consumption is high, and the cost is high. The method is characterized in that in the raw material preparation stage, a certain proportion of carbide slag, red mud, soda ash and raw material coal are added into a high-alumina material, so that the operation condition of a soda lime sintering method can be met, and the high-efficiency recovery and dissolution of valuable elements such as aluminum in aluminum ash can be synergistically promoted.

Comparative example 2

Referring to the prior art, the resource utilization of the aluminum ash is carried out, specifically, the aluminum ash is not subjected to hydrolytic denitrification and fluorine fixation, but is directly mixed, ground and homogenized with the carbide slag, the red mud and the soda ash to prepare the raw material of the aluminum material, the raw material is sprayed from the kiln tail of the rotary kiln, the coal powder is sprayed into the kiln head of the rotary kiln, the sintering temperature is controlled to be 1000-1100 ℃, the sintering time is controlled to be 20 minutes, the clinker is obtained after cooling, the clinker enters the ball mill, crushing and grinding are carried out, the clinker is dissolved to obtain dissolved slurry, and then the crude liquid and the solid slag of the sodium aluminate are obtained through sedimentation and solid-liquid separation.

The difference from example 1 is that: in this comparative example, the aluminum ash was prepared directly from the raw material formulation of example 1 without first performing hydrolysis, denitrification, and fluorine fixation, and since ammonia gas is released when the aluminum nitride breaks into water, a large amount of ammonia gas is generated on site during the raw material preparation on site, which causes environmental protection problems. If dry feeding is carried out, the smoke generated in the later period belongs to hazardous waste, and the treatment is very troublesome. In a word, under the embodiment, the production field can not be operated, and the environment-friendly requirement is not met.

Comparative example 3

The aluminum ash is treated by adopting the aluminum ash resource utilization process flow shown in figure 1. The difference from example 1 is that: in this comparative example, in the S3 raw material preparation process, the high-alumina material, the carbide slag, the red mud, and the soda ash were prepared in a ratio of a/S =3.5, the alkali ratio N/R was 1.04, and the calcium ratio C/S was 2.0 to form a raw material, and then the raw material was processed according to the subsequent processes.

In the preparation of the specific raw material, al in the raw material is supposed ₂ O ₃ With SiO ₂ All the materials come from high-alumina materials and red mud (the introduction of carbide slag is not considered at first, and the subsequent correction calculation is carried out), and the total material addition amount of the high-alumina materials and the red mud is 100g. If the addition amount of the high-alumina material is x g, the addition amount of the red mud ash is (100-x) g. Al in high-alumina material ₂ O ₃ Content of 68.12%, siO ₂ The content is 3.97%; al in red mud ₂ O ₃ 20.7% of SiO ₂ The content was 19.88%.

When the Al/Si ratio is set to 3.5, the alkali ratio N/R is 1.04 and the calcium ratio C/S is 2.0, 47.408g of high-alumina material, 52.592g of red mud, 49.93g of soda ash and 33.94g of carbide slag are added, and the actual Al/Si ratio in the mixture is 3.4288, the alkali ratio is 1.02, the calcium ratio is 1.7 and the Fe/Al ratio is 0.2429.

It can be known from the above that, for the common sintering method, the high-alumina material, the red mud and the carbide slag are used for the sintering method, when the aluminum-silicon ratio is set to be 3.5 or less than 3.5 under the conventional conditions, the aluminum-silicon ratio, the alkali ratio and the calcium ratio can meet the requirements, the iron-aluminum ratio has a large difference from the normal 0.08-0.12 ratio, and when the sintering is carried out according to the normal clinker sintering requirements, such as the sintering process condition of S4 clinker in the embodiment 1, the ring formation and the agglomeration are easy to occur, so that the clinker kiln can not normally operate.

The results of the comparative example show that when the solid wastes such as aluminum ash and red mud are recycled, if the aluminum-silicon ratio of the traditional sintering method is fixed to be 3.5, for example, and the aluminum-silicon ratio in the prepared raw material is not increased to be A/S (A/S) more than or equal to 5, the requirements of the clinker sintering process cannot be met, normal production cannot be carried out, and the aluminum oxide in the solid wastes such as aluminum ash and red mud cannot be recycled.

The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and it is apparent to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A resource utilization method of aluminum ash is characterized in that firstly, the aluminum ash is subjected to wet denitrification to prepare a high-aluminum material, then the high-aluminum material is mixed with red mud, carbide slag and caustic soda to prepare a raw material, then the raw material is sintered to obtain clinker, and finally the clinker is dissolved out to obtain sodium aluminate and solid slag, wherein the ratio of the high-aluminum material to the carbide slag to the red mud to the soda needs to satisfy the following requirements: A/S is more than or equal to 5, N/R is 1.03 +/-0.03, C/S is 1.5-2, F/A is 0.08-0.1;

the wet denitrification is catalytic denitrification: firstly, adding water into a sealed denitrification reaction tank, adding NaOH to regulate the alkali concentration to 2-3wt%, then adding aluminum ash, heating to 70-100 ℃, and carrying out alkali catalytic hydrolysis on aluminum nitride in the aluminum ash to release ammonia gas for denitrification so as to form denitrification slurry; carrying out solid-liquid separation and washing on the denitrification slurry to form a high-aluminum material and a denitrification liquid; the denitrification liquid enters a working procedure S2 for calcification fluorine fixation;

in the catalytic denitrification, the content of chloride ions in a liquid phase entering a denitrification reaction tank is monitored on line, and the liquid phase is subjected to chloride ion removal treatment.

2. The resource utilization method of aluminum ash as claimed in claim 1, wherein the raw meal is prepared by uniformly mixing the components in the raw meal according to the calculated ratio.

3. The method for recycling aluminum ash as claimed in claim 1, wherein raw material coal is added into the raw material during the preparation process, the raw material coal accounts for 3.0-5.0 wt% of the dry raw material based on fixed carbon, and the water content in the raw material is 38-42 wt%.

4. The method for recycling aluminum ash according to claim 1, further comprising step S2 of calcifying to fix fluorine: and carrying out calcification fluorine fixation on the denitrified liquid formed by hydrolyzing and denitrifying the aluminum ash so as to solidify fluoride in the denitrified liquid.

5. The aluminum ash resource utilization method of any one of claims 1 to 4, wherein the aluminum ash is secondary aluminum ash, and the aluminum ash comprises the following components in percentage by mass: al (aluminum) ₂ O ₃ 38-50 percent of the total content of the components, 25-35 percent of AIN, and MgAl ₂ O ₄ 1-10% of Fe ₂ O ₃ 1-3% of SiO ₂ 1-7% of CaF ₂ 1 to 3 percent of NaF, 1 to 5 percent of NaF and 0.5 to 1.5 percent of KF.

6. The method for recycling aluminum ash as claimed in any one of claims 1 to 4, wherein sodium aluminate is prepared by the process S5 of sodium aluminate: the clinker is crushed and ground, the clinker is dissolved out to obtain dissolved slurry, then crude sodium aluminate liquid and solid slag are obtained through sedimentation and solid-liquid separation, and the crude sodium aluminate liquid is prepared into refined sodium aluminate liquid through a vertical leaf filter.

7. The aluminum ash resource utilization method of any one of claims 1 to 4, wherein the high-aluminum material comprises the following components in percentage by mass: al (aluminum) ₂ O ₃ 60.15-73.29% of MgAl ₂ O ₄ 2.28-7.95% of Fe2O ₃ 0.87-2.38% of SiO ₂ 2.28-5.56% of CaF ₂ 0.78-2.39%, water content of 17-21.88%, and Na ₂ 0.75-2.3% of O and 1.6-2.28% of the rest.

8. The aluminum ash resource utilization method according to any one of claims 1 to 4, wherein the red mud comprises the following components in percentage by mass: al (aluminum) ₂ O ₃ 19.5-30.48% of SiO ₂ 11.58 to 23.76 percent of Fe ₂ O ₃ 19.2 to 38.24 percent of Na ₂ O accounts for 5.31 to 11.48 percent.