阅读说明：本技术 一种铝灰资源化利用方法 (Aluminum ash resource utilization method ) 是由 柯朝阳 王志平 杨光 邱玉刚 于 2021-07-06 设计创作，主要内容包括：本发明涉及一种铝灰资源化利用方法,首先将铝灰先进行湿法脱氮制备高铝料,再和赤泥、电石渣、烧碱混料配制成生料后进行烧结得到熟料,最后进行熟料溶出得到铝酸钠和固体渣,所述高铝料、电石渣、赤泥、纯碱的配比需满足：A/S≥5,N/R为1.03±0.03,C/S为1.5-2,F/A为0.08-0.1。本发明,将湿法脱氮、钙化固氟、熟料烧结工序进行结合,调节生料中的铝硅比配料,可实现铝灰、赤泥、电石渣这些固废的资源化、协同利用,固废也可以实现减量化,节能减排效果好。(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, and 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.)

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 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.

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 in the preparation process of the raw material, 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, wherein the wet denitrification comprises: and adding the aluminum ash into a water-injected denitrification reaction tank for hydrolysis denitrification.

5. The method for recycling aluminum ash as claimed in claim 4, wherein the wet denitrification is catalytic denitrification in step S1: adding the aluminum ash into a water-injected denitrification reaction tank, maintaining the alkali concentration in water to be 1-5 wt%, 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.

6. The method of claim 4, further comprising a step S2 of calcifying to fix fluorine, wherein the calcified to fix fluorine is performed on a denitrified solution formed by hydrolytic denitrification of the aluminum ash to solidify fluoride in the denitrified solution.

7. The aluminum ash resource utilization method of any one of claims 1 to 6, wherein the aluminum ash is secondary aluminum ash, and the aluminum ash comprises the following components in percentage by mass: al (Al)₂O₃38-50 percent of AlN, 25-35 percent of MgAl₂O₄1-10% of Fe₂O₃1-3% of SiO₂1-7% of CaF₂1-3%, 1-5% of NaF and 0.5-1.5% of KF.

8. The method for recycling aluminum ash as claimed in any one of claims 1 to 6, wherein sodium aluminate is prepared by the procedure 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.

9. The aluminum ash resource utilization method of any one of claims 1 to 6, wherein the high-aluminum material comprises the following components in percentage by mass: al (Al)₂O₃60.15-73.29% of MgAl₂O₄2.28-7.95% of Fe₂O₃0.87-2.38% of SiO₂2.28-5.56% of CaF₂0.78-2.39%, water content of 17-21.88%, and Na₂0.75-2.3% of O and 1.6-2.28% of the others.

10. The aluminum ash resource utilization method as claimed in any one of claims 1 to 6, wherein the red mud comprises the following components in percentage by mass: al (Al)₂O₃19.5-30.48% of SiO₂11.58 to 23.76 percent of Fe₂O₃19.2 to 38.24 percent of Na₂The content of O is 5.31-11.48%.

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 production process of electrolytic aluminum or cast aluminum 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 discloses a method for preparing sodium aluminate by using waste aluminum ash, which provides a process for producing solid sodium aluminate by using caustic soda to leach the waste aluminum ash, but has no treatment method for waste residues after the aluminum ash is dissolved out, has no relation to the treatment of waste gas generated in the process of dissolving out the aluminum ash, and obviously does not achieve the purpose of comprehensively treating the waste aluminum ash. 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 solid fluorine exists, and fluorine is mixed in the product; the nitrogen source in the aluminum ash was also not utilized. The invention patent 201611099617 relates to a method for recycling aluminum ash, which comprises hydrolyzing aluminum ash to remove nitrogen, calcining to remove fluorine, adding binder to granulate, calcining at 1500 deg.C to obtain aluminum ash clinker, spraying flue gas water to remove fluorine, and adding lime to circulating water to fix fluorine. The invention patent 201910636033 in China discloses a method for efficiently recovering valuable elements from aluminum ash, which provides the steps of preparing ammonium salt by hydrolyzing and denitrifying aluminum ash and absorbing ammonia acid, preparing sodium aluminate solution by hydrothermal reaction of desalted and deaminated aluminum ash and an alkali liquor autoclave, but not fixing fluorine, and mixing fluorine into 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, and 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 process S1 is a catalytic denitrification process: adding the aluminum ash into a water-injected denitrification reaction tank, maintaining the alkali concentration in water to be 1-5 wt%, 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 by hydrolyzing and denitrifying the aluminum ash so as to solidify the fluoride in the aluminum ash.

Further, the raw material preparation is a 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, 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 the 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 the aluminum ash comprises the following components in percentage by mass: al (Al)₂O₃38-50 percent of AlN, 25-35 percent of MgAl₂O₄1-10% of Fe₂O₃1-3% of SiO₂1-7% of CaF₂1-3%, 1-5% of NaF and 0.5-1.5% 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 invention, wet denitrification, normal-temperature calcification fluorine 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 not only is harmless treatment of solid wastes such as aluminum ash, red mud and carbide slag realized, but also resource utilization of the solid wastes such as aluminum ash, red mud and 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 is firstly 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, the 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 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 the coal can form a reducing atmosphere (CO) in sintering, and Na is added at 800 ℃ under 700-₂SO₄Reduction to Na₂S, mixing Fe₂O₃Reducing the reaction product into FeO. A part of Na₂S enters into the solution in the subsequent clinker dissolving stage, thereby achieving the purpose of removing sulfur in the aluminum ash. Another part of Na₂S 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 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 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.

Furthermore, the water content in 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 catalytic denitrification in step S1: adding the aluminum ash into a water-injected denitrification reaction tank, maintaining the alkali concentration in water to be 1-5 wt%, 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)₂O₃38-50 percent of AlN, 25-35 percent of MgAl₂O₄1-10% of Fe₂O₃1-3% of SiO₂In an order of 17％,CaF₂1-3%, 1-5% of NaF and 0.5-1.5% of KF.

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 by hydrolyzing and denitrifying the aluminum ash so as to solidify the fluoride in the aluminum ash.

Further, the fluoride includes sodium fluoride and potassium fluoride, and in the S1 catalytic denitrification step, the sodium fluoride and the potassium fluoride are dissolved into the denitrification slurry.

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

Further, the raw material preparation is a 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 step of catalytic denitrification by S1, 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: 56.8-65% of CaO and Al₂O₃1.25-4% of SiO₂2.5-7.5% of Fe₂O₃0.2-0.96%.

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 reaction time 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 2-3 wt%, then adding the secondary aluminum ash and heating to the hydrolysis temperature for hydrolysis.

Further, the denitrification reaction tank is of a sealing structure and is sequentially communicated with the ammonia absorption tower, the draught fan and the chimney through a sealing pipeline.

Further, in the step of catalytic denitrification at S1, an induced draft fan and an ammonia gas absorption tower connected to the denitrification reaction tank are started, the ammonia gas is introduced into the ammonia gas absorption tower through the induced draft fan, the ammonia gas forms low-concentration ammonia water and residual gas in the ammonia gas absorption tower through spray water, and the low-concentration ammonia water is sent to an ammonia water storage tank for temporary storage and is subjected to denitrification treatment; the residual gas is discharged to the atmosphere.

Further, in the step of catalytic denitrification by S1, 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 step of catalytic denitrification by S1, superheated steam is introduced 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 0.6 MPa.

Further, in the step of catalytic denitrification by S1, 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 step of catalytic denitrification at S1, the content of chloride ions in the liquid phase entering the denitrification tank is monitored, and when the content of chloride ions is high, the amount of the liquid phase entering is stopped or reduced, and the liquid phase is subjected to a treatment for removing chloride ions; 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 denitrification liquid, the high-aluminum material is fed into a raw material preparation process of S3 to be mixed, and the denitrification liquid enters a fluorine fixing reaction tank of the S2 calcification fluorine fixing process to fix fluorine.

Further, in the calcified fluorine fixation step of S2, the denitrified solution is flowed into the fluorine fixation reaction tank, and 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 fixation reaction at room temperature to generate calcium fluoride.

Further, in the step of calcifying to fix fluorine in S2, the solid-fluorine reaction solution generated after the solid-fluorine reaction is pumped into a chamber filter press by a slurry pump to be subjected to solid-liquid separation and washing to form calcium fluoride and a liquid phase, the liquid phase enters the denitrification groove of the step of catalytic denitrification in S1 for recycling, and the calcium fluoride is sent to a solid waste storage yard.

Further, the high-aluminum material comprises the following components in percentage by mass: al (Al)₂O₃60.15-73.29% of MgAl₂O₄2.28-7.95% of Fe₂O₃0.87-2.38% of SiO₂2.28-5.56% of CaF₂0.78-2.39%, water content of 17-21.88%, and Na₂0.75-2.3% of O and 1.6-2.28% of the others.

Further, the carbide slag comprises the following components in percentage by mass: 56.8-65% of CaO and Al₂O₃1.25-4% of SiO₂2.5-7.5% of Fe₂O₃0.2-0.96%.

Further, the red mud comprises the following components in percentage by mass: al (Al)₂O₃19.5-30.48% of SiO₂11.58 to 23.76 percent of Fe₂O₃19.2 to 38.24 percent of Na₂The content of O is 5.31-11.48%.

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, it is characterized byThe calcium carbide slag comprises 65 percent (wt%) of calcium oxide and Al₂O₃0.25% (wt%) SiO₂7.9% (wt%) Fe₂O₃0.96% (wt%).

Further, in the step of preparing the raw material of S3, the method further comprises wet milling the raw material in an ore pulp ball mill to obtain a homogenized raw material, wherein the ball milling time is 15-60min, the particle size of the milling material 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, wherein the temperatures of the zones are 120 ℃, 120-; the pressure of the spray gun at the kiln head is 1.8-2.2MPa, and the pressure at the kiln tail is more than or equal to-500 Pa.

Further, in the S4 clinker sintering procedure, the coal dust is injected into the kiln head of the rotary kiln, and H in the coal dust₂O 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 of S4, the method further includes performing electric dust removal treatment on flue gas generated by the rotary kiln during calcination of the raw meal to recover residual heat in the flue gas, and using the flue gas to heat the raw meal in the step of preparing the raw meal of S3 or to heat water in the denitrification reaction tank in the step of catalytic denitrification of S1.

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 S5 sodium aluminate preparation process, the clinker is crushed and ground to a particle size of not more than 10 mm.

Further, in the S5 sodium aluminate production process, the vertical leaf filter removes suspended solids by filtration.

Further, in the step of preparing sodium aluminate S5, 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 crude sodium aluminate solution contains NaAl0H₄NaOH and Na₂CO₃According to Al₂O₃And calculating the total alkali, wherein the Al in the sodium aluminate crude liquid₂O₃The content is 100-170 g/l, and the total alkali content is 105-170 g/l.

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%.

The present invention is described in detail below with reference to the drawings and the specific embodiments, which are not repeated herein, but the embodiments of the present invention are 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)₂O₃38-50 percent of AlN, 25-35 percent of MgAl₂O₄1-10% of Fe₂O₃1-3% of SiO₂1-7% of CaF₂1-3%, 1-5% of NaF and 0.5-1.5% of KF.

The red mud comes from an alumina plant, and the red mud comprises the following components in percentage by mass: al (Al)₂O₃19.5-30.48% of SiO₂11.58 to 23.76 percent of Fe₂O₃19.2 to 38.24 percent of Na₂The content of O is 5.31-11.48%.

The carbide slag is waste slag generated in PVC production in a certain chemical plant, and comprises the following components in percentage by mass: 56.8-65% of CaO and Al₂O₃1.25-4% of SiO₂2.5-7.5% of Fe₂O₃0.2-0.96%.

Coal: anthracite coal with low sulfur content and H in coal₂O 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 catalytic denitrification of aluminum ash

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 2-3 wt%, 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+3H₂O＝Al(OH)₃↓+NH₃×) @. 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 is absorbed on the surface of the filler to form low-concentration ammonia water through water mist sprayed from the top of the absorption tower and ammonia gas rising from the bottom of the tower, the low-concentration ammonia water is sent into an ammonia water storage tank for temporary storage, then the low-concentration ammonia water is pumped into a boiler room for denitration, and the ammonia gas is purified to obtain the ammonia gas residue, and then the ammonia gas residue 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 water-containing solid high-aluminum material is sent into an ore pulp grinding process, aluminum, silicon and other valuable element ingredients are dissolved out in an ore pulp ball mill, and the denitrification liquid enters a calcification fluorine fixation 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:

Al₂O₃68.12% (wt%) MgAl₂O₄6.31% (wt%) Fe₂O₃1.05% (wt%) of SiO₂3.97% (wt%) CaF₂0.86% (wt%) of Na₂O 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

Injecting denitrogenation liquid after denitrogenation into the solid fluorine reaction tank, adding the solid fluorine agent carbide slag slurry, calcium oxide in the carbide slag slurry and sodium fluoride and potassium fluoride in the denitrogenation liquid react at normal temperature to generate calcium fluoride, and the process does not need to be heated additionally, and the reaction principle is as follows:

2NaF+CaO+H₂O＝CaF₂+2NaOH,2KF+CaO+H₂O＝CaF₂+2KOH

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 in 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) Preparation of raw material S3

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 percent, aluminum oxide accounts for 1.95 percent, silicon oxide accounts for 3.5 percent, ferric oxide accounts for 0.96 percent, and the other accounts for 3.08 percent; loss on ignition: 25.76 percent;

the mass percentage of the red mud is Al₂O₃20.7%, S iO₂19.88% of Fe₂O₃30.2% of Na₂9.82 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 is 7, the ratio of alkali to N/R is 1.04, the ratio of calcium to C/S is 2.0, the ratio of iron to aluminum F/A is 0.098, the ratio of raw coal is 4.5 percent (wt%), the fineness is plus 120# < 14%, and the water content is 38-42 percent (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 material₂O₃With SiO₂All come from high-alumina materials and red mud (not considering the introduction of carbide slag, after the subsequent correction calculation), and the total material addition amount of the high-alumina materials and the red mud is 100 g. 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 material₂O₃68.12% of SiO₂The content is 3.97%; al in red mud₂O₃The content of the active carbon is 20.7 percent,SiO₂the content was 19.88%.

When the Al/Si ratio is set to 7.0, the amount of the added aluminum material is 74.602 g, and the amount of the added 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 ingredients in the raw meal is basically similar to that in the raw meal 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-section 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 this embodiment, the carbon separation mother liquor formed during the preparation of aluminum hydroxide by the carbon separation method can be used to recycle sodium carbonate, and the recycled mother liquor is added to prepare the raw material.

(4) Sintering of S4 clinker

Atomizing and spraying the raw materials from the tail of the rotary kiln, spraying finished 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 the clinker.

In the embodiment, the rotary kiln is divided into a drying zone, a preheating zone, a decomposition zone, a sintering zone and a cooling zone in sequence from the kiln tail to the kiln head according to functions, the temperature of each zone is 120 ℃, 120-; 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 kiln₂O 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. In the clinker sintering 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 sodium aluminate crude liquid product is finally prepared through aluminum ash catalytic denitrification, calcified fluorine fixation, raw material preparation, clinker sintering and sodium aluminate preparation treatment, wherein the sodium aluminate crude liquid contains NaAl0H₄NaOH and Na₂CO₃According to Al₂O₃And the Al in the sodium aluminate solution is calculated according to total alkali₂O₃In an amount of110 g/l, the total base content is 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 liquor after washing can also be used for dissolving out clinker, so that the internal recycling of the system is realized, no waste water is discharged, and the harmless treatment of solid waste aluminum ash is realized and the resource utilization of valuable elements such as aluminum, nitrogen and the like is obtained. The sintering flue gas waste heat in the system is also 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 catalytic denitrification of aluminum ash

Adjusting the alkali concentration of the aqueous solution in the denitrification reaction tank to be 1 wt%, then adding secondary aluminum ash, and controlling the liquid-solid ratio in the denitrification reaction tank to be 6: 1. the flue gas waste heat generated by the rotary kiln in the subsequent S4 clinker sintering process is recovered, the water solution in the denitrification reaction tank is directly heated through a heat exchange tube, the temperature rise condition of the water solution in the denitrification reaction tank is monitored on line, superheated steam with the temperature of 250 ℃ and the pressure of 4 kilograms is supplemented into the water solution in the denitrification reaction tank, the temperature of the water solution in the denitrification reaction tank is raised to 90 ℃ and kept, and the mixture is stirred and reacted 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) Preparation of raw material S3

Adding high-alumina material containing 19% water into a ball mill, stirring, feeding into a pulp ball mill for grinding, homogenizing, dissolving, and mixing to obtain a raw material pulp with water content of 42%.

(3) Sintering of S4 clinker

And atomizing and 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 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 example, qualified refined sodium aluminate solution product is finally prepared through catalytic denitrification of aluminum ash, calcified fluorine fixation, raw material preparation, clinker sintering and sodium aluminate preparation, wherein the crude refined sodium aluminate solution contains NaAl0H₄NaOH and Na₂CO₃According to Al₂O₃And Al in sodium aluminate solution calculated by total alkali₂O₃The 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%, and the recovery rate of alumina in the solid waste consisting of the aluminum ash and red mud is more than 93%. . 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

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) and S3 raw material preparation, which comprises adding 21% water-containing high-alumina material into a ball mill, stirring, feeding into an ore pulp ball mill, grinding, homogenizing, dissolving, and mixing.

(2) And S4, sintering clinker, 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 the clinker.

(3) Preparing sodium aluminate by catalytic denitrification of aluminum ash, calcification fluorine fixation, raw material preparation, clinker sintering and sodium aluminate preparation treatment to finally prepare a qualified sodium aluminate crude liquid product, wherein the sodium aluminate crude liquid contains NaAl0H₄NaOH and Na₂CO₃According to Al₂O₃And all alkaliCalculating Al in the sodium aluminate solution₂O₃The 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%, 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. 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 S2, calcification fluorine fixing is carried out, after the fluorine fixing reaction is finished, the fluorine fixing reaction liquid is pumped into a chamber 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 S1 for catalytic denitrification for recycling.

The recovery rate of nitrogen in the aluminum ash of the finally prepared sodium aluminate solution product 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%. 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 the catalytic denitrification process is performed in time at S1, the accumulation of primary salts such as NaCl and KCl generated from chlorine eventually causes the corrosion of the 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 of preparing raw material S3, the raw material prepared from high-alumina material, carbide slag, red mud, soda ash and raw coal in a preparation tank is stirred, homogenized and proportioned only in the preparation tank, and is not sent into a pulp ball mill for grinding to prepare the raw material. The final product of the crude liquid of sodium aluminate prepared by the embodiment, wherein the crude liquid of sodium aluminate contains NaAl0H₄NaOH and Na₂CO₃According to Al₂O₃And the Al in the sodium aluminate solution is calculated by total alkali₂O₃The 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 is 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

Referring to the prior art, the aluminum ash is recycled, specifically, firstly, the aluminum ash is subjected to hydrolysis denitrification and solid-liquid separation, the denitrification liquid is subjected to calcification fluorine fixation, the separated high-aluminum material is added with sodium carbonate and then directly sent into an ore pulp ball mill for full grinding to form high-aluminum material raw material, the raw material is sprayed from the tail of the rotary kiln, meanwhile, coal powder is sprayed into the kiln head of the rotary kiln, and the sintering temperature is controlled to be 1000-fold and 1100 ℃ for sintering.

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 aluminum ash is recycled, specifically, the aluminum ash is not subjected to hydrolysis denitrification and fluorine fixation, but is directly mixed, ground and homogenized with carbide slag, red mud and sodium carbonate to prepare an aluminum raw material, the raw material is sprayed from the kiln tail of a rotary kiln, coal powder is sprayed into the kiln head of the rotary kiln, the sintering temperature is controlled to be 1000-plus-1100 ℃, the sintering time is 20 minutes, clinker is obtained after cooling, the clinker enters a ball mill, crushing and grinding are carried out, the clinker is dissolved to obtain dissolved slurry, and crude liquid and solid slag of 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 step of preparing the raw material S3, the high-alumina material, the carbide slag, the red mud, and the soda ash were prepared in a ratio of a/S to 3.5, an alkali ratio N/R to 1.04, and a calcium ratio C/S to 2.0 to form a raw material, and then processed according to the subsequent processes.

In the preparation of the specific raw material, Al in the raw material is supposed₂O₃With SiO₂All the materials are from high-alumina materials and red mud (not considering the introduction of carbide slag at first, and after the subsequent correction calculation), and the total material addition amount of the high-alumina materials and the red mud is 100 g. If the adding amount of the high-alumina material is x g, the adding amount of the red mud ash is (100-x) g. Al in high-alumina material₂O₃68.12% of SiO₂The content is 3.97%; al in red mud₂O₃20.7% of SiO₂The 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, the adding amount of the high-alumina material is 47.408g, the adding amount of the red mud is 52.592g, the adding amount of the soda ash is 49.93g and the adding amount of the carbide slag is 33.94g, the actual Al/Si ratio in the mixed material 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 seen from the above that, for the ordinary 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 with the normal 0.08-0.12 ratio, and when the sintering is carried out under the normal clinker sintering requirement, such as the S4 clinker sintering process condition in the embodiment 1, the ring formation and the agglomeration are easy to occur, so that the clinker kiln cannot 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.