Wet washing-high-temperature roasting combined treatment method for secondary aluminum ash

Abstract

The invention discloses a wet washing-high-temperature roasting combined treatment method for secondary aluminum ash, which comprises the following steps: firstly, carrying out wet washing treatment on the secondary aluminum ash to remove most of soluble salts and alkali metal elements in the secondary aluminum ash, reduce the flue gas amount in the roasting process and avoid the influence of the alkali metal elements on the performance of a refractory material; then, the washed secondary aluminum ash is subjected to high-temperature roasting, after the secondary aluminum ash is subjected to wet washing-high-temperature roasting treatment, a high-alumina refractory material with aluminum oxide and magnesium aluminate spinel as main components can be obtained, the high-alumina refractory material can be directly used as aggregate of the refractory material, and high-value resource utilization of the secondary aluminum ash is achieved; meanwhile, secondary aluminum ash wet washing and high-temperature roasting treatment process parameters are designed and optimized, so that the operation cost is reduced, and the treatment efficiency is improved; in addition, in the wet washing process, the ammonium chloride solution is used as washing liquid for the first time, and the content of aluminum oxide can be effectively increased on the premise that the removal rate of alkali metal elements is kept.

Description

Technical Field

[0001] The invention belongs to the technical field of secondary aluminum ash resource processing, and specifically relates to a method for the combined treatment of secondary aluminum ash by wet water washing and high-temperature roasting. Background Art

[0002] In the electrolytic aluminum, aluminum processing and recycled aluminum industries, the slag produced during the smelting and casting of aluminum or aluminum alloys is called primary aluminum ash; the slag produced after melting and extracting aluminum from the primary aluminum ash is secondary aluminum ash, which has a very complex composition, mainly including alumina, magnesium aluminum spinel, aluminum nitride, metallic aluminum, chlorides, fluorides, etc., and has dual attributes such as resource and pollution. Secondary aluminum ash has been included in the 2021 version of the "National List of Hazardous Wastes" and is a hazardous solid waste. Due to the lack of low-cost, large-scale and relatively mature treatment processes, aluminum production companies currently mainly treat secondary aluminum ash through traditional stockpiling or landfilling methods, which not only fails to effectively utilize the valuable metal aluminum element, but also brings about problems such as occupying land resources and environmental pollution. Therefore, exploring an economical, environmentally friendly and efficient disposal method is the focus of the resource utilization of secondary aluminum ash.

[0003] Many aspects of research and practice have been conducted to address this problem. A Chinese patent document (application number: CN202410309546.9) discloses a method for efficient and harmless treatment of secondary aluminum ash, in which the ground and screened secondary aluminum ash is mixed with a sodium hydroxide solution, hydrolyzed for denitrification, and then a mixture of lime and calcium chloride is added for defluorination, which efficiently removes nitrogen ions and fluoride ions from the secondary aluminum ash. However, this process does not pay attention to the changes in the content of the valuable metal aluminum element. A Chinese patent document (application number: CN202310832015.3) discloses a method for the combined treatment of secondary aluminum ash by ball milling sorting-low temperature roasting-water washing and leaching, in which the secondary aluminum ash is sorted by particle size, the medium-sized secondary aluminum ash is subjected to low-temperature roasting, and the fine-sized secondary aluminum ash is treated by low-temperature roasting with an electrolytic aluminum electrolyte. After treatment, the medium-sized, fine-sized and coarse-sized secondary aluminum ashes are washed and leached together to obtain harmless secondary aluminum ash and inorganic salts. This method achieves effective recovery of inorganic salts, but the method directly roasts, which can easily cause flue gas to corrode equipment and pipelines, reducing the service life. A Chinese patent document (application number: CN202311783106.9) discloses a method for resource utilization of secondary aluminum ash, which uses ultrasonic enhanced alkaline leaching, and the leachate is separated by seed crystals, roasted and dehydrated to produce high-grade alumina raw materials, and the leached slag is used to prepare high-performance adsorption materials. Although this method has a short process flow, it still has problems such as high price of alkaline additives, large addition amount, and long reaction time. A Chinese patent document (application number: CN202310348500.3) discloses a method for resource treatment of secondary aluminum ash, which obtains polyaluminum chloride solution through alkaline leaching, acid leaching, roasting activation and leaching processes to achieve the recycling of aluminum in secondary aluminum ash, but there are disadvantages such as large acid and alkali consumption and low aluminum ash slag recycling rate.

[0004] In the process of resource utilization of secondary aluminum ash, two technical routes, wet method and pyrotechnic method, have basically been formed at this stage to deal with the treatment and disposal of secondary aluminum ash. Wet treatment is mainly divided into acid washing and alkaline washing. Studies have found that although direct wet treatment has low energy consumption, it has the disadvantages of complicated process conditions, large acid and alkali consumption, and heavy secondary pollution; pyrotechnic method, that is, high-temperature roasting, not only has strict restrictions on the impurity content in secondary aluminum ash, but also has problems such as large flue gas volume and complex composition, and corrosion of pipelines during the roasting process. At present, there are not many cases of industrial treatment of secondary aluminum ash, and most of them are in the laboratory research stage. In the process of application, specific process routes need to be customized for different utilization methods. Summary of the invention

[0005] In view of the shortcomings and deficiencies of the existing secondary aluminum ash resource utilization technology, by comparing the advantages and disadvantages of the two treatment processes of secondary aluminum ash wet and pyrometallurgical methods, the present invention proposes for the first time a wet water washing-high temperature roasting combined treatment method.

[0006] First, the secondary aluminum ash is subjected to wet water washing to remove most of the soluble salts and alkali metal elements, reduce the amount of flue gas during the roasting process, and avoid the influence of alkali metal elements on the performance of high-aluminum refractory materials; secondly, the secondary aluminum ash is roasted at high temperature to increase the content of alumina to ensure the quality and stability of the material. At the same time, the process parameters of wet water washing and high-temperature roasting of secondary aluminum ash are designed and optimized to reduce operating costs and improve processing efficiency. In addition, the use of ammonium chloride solution as a washing liquid was proposed for the first time in the wet water washing process. While maintaining the removal rate of alkali metal elements, the alumina content was effectively increased, thereby improving the quality of high-aluminum refractory materials.

[0007] The technical solution of the present invention is as follows:

[0008] A method for the combined treatment of secondary aluminum ash wet washing and high-temperature roasting comprises the following steps:

[0009] (1) Pretreatment

[0010] The secondary aluminum ash is screened and dry-milled to obtain secondary aluminum ash with uniform particle size;

[0011] Secondary aluminum ash includes secondary aluminum ash generated by any industry such as aluminum electrolysis, aluminum recycling or aluminum processing;

[0012] Specifically, screening refers to: passing the secondary aluminum ash through a 60-mesh standard sieve, and the cumulative yield of the sieved material is greater than 98%; the sieved material is dry-milled to obtain secondary aluminum ash with uniform particle size; the ball mill speed of the dry ball mill is controlled at 200 to 400 r / min (preferably 300 r / min), and the time is controlled at 10 to 60 min (preferably 30 min);

[0013] (2) Wet washing

[0014] The secondary aluminum ash obtained in step (1) is mixed with a water washing liquid and washed with water to obtain a secondary aluminum ash water-washed sample;

[0015] The washing liquid is ultrapure water or an aqueous solution of ammonium chloride; preferably, the mass fraction of the aqueous solution of ammonium chloride is 5 to 20%, such as 5%, 10%, 15%, 20%, and particularly preferably 15%;

[0016] The preferred solid-liquid ratio of secondary aluminum ash to water washing liquid is 1:1-5, g / mL; for example, 1:1, 1:2, 1:3, 1:4, 1:5, g / mL; the optimal solid-liquid ratio is 1:3, g / mL;

[0017] The preferred water washing temperature is 10-100°C, such as 20, 40, 60, 80, 100°C; the optimal water washing temperature is 60°C;

[0018] The preferred washing time is 1 to 5 hours, for example 1, 2, 3, 4, 5 hours; the optimal washing time is 3 hours;

[0019] The preferred water washing stirring speed is 100 to 1000 r / min, such as 200, 400, 600, 800, 1000 r / min; the optimal water washing stirring speed is 600 r / min;

[0020] (3) High temperature roasting

[0021] The secondary aluminum ash water-washed sample obtained in step (3) is subjected to high-temperature roasting to obtain a high-aluminum refractory material;

[0022] The high temperature calcination temperature is 700-1500° C., for example, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500° C.; the calcination time is 1-5 hours, for example, 1, 2, 3, 4, 5 hours;

[0023] The optimal calcination temperature is 1300°C and the optimal calcination time is 4h;

[0024] The preferred high temperature calcination heating rate is 6°C / min;

[0025] The calcination atmosphere was air, and the gas flow rate was 4 L / min.

[0026] The present invention proposes for the first time a method of treating secondary aluminum ash by wet washing and high temperature roasting, and designs and optimizes the process parameters of wet washing and high temperature roasting of secondary aluminum ash, so as to reduce the operation cost and improve the processing efficiency. In the wet washing process, it is proposed for the first time to use ammonium chloride solution as the washing liquid, which effectively increases the aluminum oxide content and improves the quality of high-aluminum refractory materials while maintaining the removal rate of alkali metal elements.

[0027] The technical principles of the present invention include:

[0028] There are reports in the prior art that ammonium chloride is used as a heavy metal removal agent for resource processing of secondary aluminum ash (for example, CN110548753A). The principle is: ammonium chloride is added to the roasting process of secondary aluminum ash to convert the heavy metal elements contained in the secondary aluminum ash into low-melting-point gaseous compounds, which are separated from the secondary aluminum ash.

[0029] Different from what has been reported, the ammonium chloride in this application is used in the secondary aluminum ash wet treatment process. Its function is not to remove impurities, but to inhibit the hydrolysis of aluminum nitride in the secondary aluminum ash during the water washing process and stabilize the content of aluminum oxide in the water washing product. During the secondary aluminum ash water washing process, a major problem is that AlN will react with water to generate NH 3 , while NH 3 Soluble in water, which will increase the pH of the water wash solution. AlN, Al(OH) 3 With OH - Reaction to form AlO 2- , resulting in a decrease in the content of alumina in the washed product; at the same time, NH 3 The emission of NH will cause serious environmental problems. 4 Cl is a strong electrolyte and dissociates into NH 4 + On the one hand, NH 4 + As the concentration increases, the NH 3 The solubility in water hinders the hydrolysis reaction of AlN. On the other hand, NH 4 + Hydrolyzes and binds OH in the solution - , while producing H + , which will reduce the pH value of the water wash, thereby inhibiting OH - With AlN, Al(OH) 3 Reaction to form AlO 2 - process, thereby reducing the loss of aluminum in the water-washed product; and, NH 4 Cl does not react with metallic aluminum, aluminum nitride, aluminum oxide, etc.

[0030] The present invention uses ammonium chloride solution as the secondary aluminum ash washing liquid. Research has found that under the premise of ensuring the removal rate of alkali metals K and Na, the ammonium chloride solution can effectively inhibit the hydrolysis of aluminum nitride, significantly reduce the loss of aluminum during the washing process, and stabilize the aluminum oxide content in the washing product. This technical feature has not been previously studied or reported.

[0031] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in:

[0032] 1. The present invention introduces a process of wet water washing-high temperature roasting combined treatment. The function of the wet water washing process is to remove a large amount of soluble salts in the secondary aluminum ash, such as chlorides, fluorides, etc., to prevent such substances from volatilizing into the flue gas during the subsequent high temperature roasting process, resulting in complex flue gas composition, great difficulty in separation and recovery, severe flue corrosion and other problems; remove alkali metal elements potassium and sodium to prevent them from reacting with substances such as alumina and silicon dioxide to generate low melting point compounds, causing softening of refractory materials, so it is particularly critical to wet wash the secondary aluminum ash.

[0033] 2. The present invention optimizes process parameters such as water washing temperature, water washing time, solid-liquid ratio, water washing speed, roasting temperature, roasting time, etc. to obtain the optimal process parameters, which provides an important reference and scientific basis for the harmless treatment and resource utilization of secondary aluminum ash.

[0034] 3. The present invention innovatively proposes to use ammonium chloride solution as the water washing liquid, which effectively inhibits the hydrolysis of aluminum nitride and effectively increases the aluminum oxide content while maintaining the removal rates of K and Na.

[0035] 4. By subjecting the best water-washed sample of secondary aluminum ash to high-temperature roasting, the elements such as N, Cl, F, K, and Na are further removed, and the aluminum, aluminum nitride, aluminum carbide in the secondary aluminum ash, and the aluminum hydroxide produced after water washing are converted into stable aluminum oxide.

[0036] 5. After being processed, the secondary aluminum ash is used to obtain a high-alumina refractory material with alumina and magnesia-alumina spinel as the main components, wherein the alumina content reaches about 88%, which meets the requirements of alumina content (≥80%) in the physical and chemical index LZ-80 in "GB / T 2988-2012". It can be directly used as an aggregate of refractory materials, realizing the high-value resource utilization of secondary aluminum ash. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 : Schematic diagram of the process flow of the present invention.

[0038] Figure 2 : A comparison diagram of the actual objects before and after the secondary aluminum ash treatment of the present invention, wherein the left side is the raw material, the middle is the water-washed sample, and the right side is the roasted sample.

[0039] Figure 3 :(a) - XRD diagram of secondary aluminum ash before and after water washing; (b) - XRD diagram of the optimal water-washed sample and the secondary aluminum ash after calcination at 700-1000℃ for 2h; (c) - XRD diagram of secondary aluminum ash after calcination at 1000-1500℃ for 2h; (d) - XRD diagram of secondary aluminum ash after calcination at 1300℃ for 1-5h.

[0040] Figure 4 : Effect of the optimal process parameters of wet washing on K and Na removal rates (a) and alumina content (b) in Example 2.

[0041] Figure 5 : F and Cl ion concentrations in the secondary aluminum ash leaching solution (a) and F and Cl ion mass concentrations in the secondary aluminum ash (b) in Example 2.

[0042] Figure 6 : The main element content (a) and removal rate (b) of secondary aluminum ash washed with ammonium chloride of different concentrations in Example 3, as well as the influence of alumina content (c).

[0043] Figure 7 : Effect of different calcination temperatures on K and Na removal rates (a) and alumina content (b) in Example 4.

[0044] Figure 8 : Effect of different calcination times on K and Na removal rates (a) and alumina content (b) in Example 4. DETAILED DESCRIPTION

[0045] The present invention is further described below by means of specific embodiments, but the protection scope of the present invention is not limited thereto.

[0046] Taking the secondary aluminum ash produced by a renewable resource recycling enterprise in my country as an example, the main metal elements of the secondary aluminum ash raw materials treated by the embodiment of the present invention and the content of non-metallic elements that need to be paid attention to during the experiment are shown in Table 1. In addition, the non-metallic elements also include: O (22.6%), N (4.88%), and other trace metal elements: Mn, Zn, Ni, Ba, etc., whose content accounts for about 1%.

[0047] Table 1 Main element content of secondary aluminum ash in Example 1 (%)

[0048]

[0049] Pretreatment of secondary aluminum ash

[0050] Screening: The secondary aluminum ash raw material is passed through a 60-mesh standard sieve and mechanically vibrated to remove large aluminum particles, iron filings, and mixed flocs.

[0051] Ball milling: The secondary aluminum ash sieve was dry-milled using a drum ball mill for 0.5 h, with the ball mill speed set at 300 r / min.

[0052] Example 1: Optimization of process parameters for wet washing of secondary aluminum ash

[0053] (1) Effect of water washing temperature on element removal rate and alumina content

[0054] The pretreated secondary aluminum ash is mixed with a washing liquid (ultrapure water). The washing time is preferably 3 hours, the washing speed is preferably 600 r / min, and the solid-liquid ratio is preferably 1:3 g / mL. At a washing temperature of 20°C, the removal rates of K and Na are 43.0% and 53.4%, respectively, and the aluminum oxide content is 73%; at a washing temperature of 60°C, the removal rates of K and Na are 50.3% and 70.4%, respectively, and the aluminum oxide content is 71.5%; at a washing temperature of 100°C, the removal rates of K and Na are 54.3% and 73.5%, respectively, and the aluminum oxide content is 67.1%.

[0055] (2) Effect of washing time on element removal rate and alumina content

[0056] The water washing temperature is preferably 60°C, the solid-liquid ratio is preferably 1:3g / mL, the water washing speed is preferably 600r / min, and when the water washing time is 1h, the K and Na removal rates are 42.4% and 52.0%, respectively, and the alumina content is 74.8%; when the water washing time is 3h, the K and Na removal rates are 50.5% and 70.1%, respectively, and the alumina content is 71.6%; when the water washing time is 5h, the K and Na removal rates are 53.1% and 73.3%, respectively, and the alumina content is 66.6%.

[0057] (3) Effect of solid-liquid ratio on element removal rate and alumina content

[0058] The washing time is preferably 3h, the washing temperature is preferably 60°C, and the washing speed is preferably 600r / min. At a solid-liquid ratio of 1:1g / mL, the K and Na removal rates are 39.8% and 52.9%, respectively, and the alumina content is 65.9%; at a solid-liquid ratio of 1:3g / mL, the K and Na removal rates are 50.8% and 70.1%, respectively, and the alumina content is 70.8%; at a solid-liquid ratio of 1:5g / mL, the K and Na removal rates are 54.1% and 74.7%, respectively, and the alumina content is 74.0%.

[0059] The reduction of solid-liquid ratio from 1:1g / mL to 1:3g / mL has a significant effect on the removal rate of K and Na. This is mainly because the reduction of solid-liquid ratio, on the one hand, effectively reduces the viscosity of the material, is conducive to the full contact and mixing of secondary aluminum ash, and improves the removal rate of alkali metals K and Na; on the other hand, the reduction of solid-liquid ratio also reduces the pH of the water wash liquid and reduces OH - The concentration of 2:1 inhibited its reaction with AlN and reduced the loss of aluminum during the washing process. When the solid-liquid ratio was further reduced to 1:5 g / mL, the removal rates of K and Na reached their maximum values ​​(54.1% and 74.7%), and the alumina content also reached its maximum value (74.0%). As the solid-liquid ratio decreased, in addition to soluble salts, other substances such as Na 3 AlF 6 , CaF 2 The results showed that the 20% solid-liquid ratio was still insoluble in water, while the removal rates of K and Na and the content of alumina did not increase significantly. In addition, a lower solid-liquid ratio would increase water consumption, wastewater treatment volume, equipment load, treatment burden and operating costs. Therefore, a solid-liquid ratio of 1:3 g / mL was selected as the optimal solid-liquid ratio in subsequent studies.

[0060] (4) Effect of water washing speed on element removal rate and alumina content

[0061] The washing time is preferably 3h, the washing temperature is preferably 60°C, the solid-liquid ratio is preferably 1:3g / mL, and at a washing speed of 200r / min, the K and Na removal rates are 46.5% and 67.6%, respectively, and the alumina content is 71.4%; at a washing speed of 600r / mim, the K and Na removal rates are 50.9% and 70.2%, respectively, and the alumina content is 70.1%; at a washing speed of 1000r / mim, the K and Na removal rates are 52.8% and 71.0%, respectively, and the alumina content is 68.4%.

[0062] Example 2: Secondary aluminum ash washing experiment under optimal conditions

[0063] (1) Stability washing test under optimal washing parameters

[0064] Through Example 1, the optimal wet washing parameters were determined: washing temperature 60°C, washing time 3h, solid-liquid ratio 1:3g / mL, stirring speed 600r / min, and the secondary aluminum ash wet washing stability experiment was carried out under these conditions. Figure 4 As shown in the figure, the removal effect of K and Na elements is obvious and stable, with K removal rate of about 50% and Na removal rate of about 70%. 2 O 3 The average content is maintained at about 71%. In general, the factors affecting the removal rate of K and Na elements are: solid-liquid ratio > washing temperature > washing time > stirring speed.

[0065] (2) Effect of water washing process on F and Cl removal rate

[0066] The concentrations of fluorine and chlorine in the secondary aluminum ash raw material leachate were 3.73 mg / L and 1138.9 mg / L, respectively, and the concentrations of fluorine and chlorine in the secondary aluminum ash water-washed sample leachate were reduced to 3.07 mg / L and 9.09 mg / L, respectively; the mass concentrations of fluorine and chlorine in the secondary aluminum ash raw material were 0.07 mg / Kg and 30.52 mg / Kg, respectively, and the mass concentrations of fluorine and chlorine in the secondary aluminum ash water-washed sample were reduced to 0.06 mg / Kg and 0.29 mg / Kg, respectively. After water washing, the contents of fluorine and chlorine have reached the national prescribed limit range, and the removal rates of fluorine and chlorine have reached 17.58% and 99.0%, respectively. Figure 5 shown.

[0067] The wet water washing treatment method of secondary aluminum ash in the present invention is a low-cost processing process, which can remove harmful impurities, improve the efficiency of subsequent processing, and has a wide range of applications; this method can not only be used alone, but also can be used in combination with a high-temperature roasting treatment method. From the experimental process and test results of Examples 1 to 2, it is concluded that the optimal parameters of the wet water washing of the present invention are: water washing temperature 60°C, water washing time 3h, solid-liquid ratio of 1:3g / mL, and stirring speed 600r / min.

[0068] Example 3: Effect of ammonium chloride solution on element removal rate and alumina content

[0069] Under the optimal wet washing parameters of step (1) of Example 2, an ammonium chloride solution was used for washing experiments. When the concentration of the ammonium chloride solution was 5%, the removal rates of K and Na were 50.6% and 70.2%, respectively, and the aluminum oxide content was 75.3%; when the concentration of the ammonium chloride solution was 15%, the removal rates of K and Na were 51.7% and 71.1%, respectively, and the aluminum oxide content was 82.6%; when the concentration of the ammonium chloride solution was 20%, the removal rates of K and Na were 49.8% and 68.3%, respectively, and the aluminum oxide content was 84.1%. Figure 6 shown.

[0070] When the concentration of ammonium chloride solution is increased to 20%, although the alumina content is increased, it is only increased by about 2%; while the removal rate of alkali metals K and Na does not increase but slightly decreases. This change may be related to the increase in chloride ion concentration in the solution. The increase in chloride ion concentration will hinder the further dissolution of chloride salts and reduce their solubility in the solution. However, the alumina content in the water-washed product only increases by about 2%, and the content increase is not obvious. Therefore, on the basis of ensuring the removal rate of alkali metals K and Na and increasing the alumina content, 15% ammonium chloride solution can be selected as the water washing solution.

[0071] Example 4: Optimization of process parameters for secondary aluminum ash high temperature roasting

[0072] (1) Effect of calcination temperature on element removal rate and alumina content

[0073] The secondary aluminum ash washed with water under the optimal water washing parameters in step (1) of Example 2 was subjected to a roasting experiment. Under the conditions of a heating rate of 6°C / min, a gas flow rate of 4L / min, and a holding time of preferably 2h, at a roasting temperature of 700°C, the removal rates of K and Na were 10.70% and 16.8%, respectively, and the aluminum oxide content was 78.2%; at a roasting temperature of 1300°C, the removal rates of K and Na were 40.3% and 42.9%, respectively, and the aluminum oxide content was 84.2%; at a roasting temperature of 1500°C, the removal rates of K and Na were 42.2% and 45.1%, respectively, and the aluminum oxide content was 85.9%.

[0074] Depend on Figure 3 XRD spectrum analysis: At 1300℃, Al 2 O 3 and MgAl 2 O 4 The main diffraction peak is the high-alumina refractory material after sintering. 2 O 3 and MgAl 2O 4 This shows that high temperature roasting can be beneficial to the removal of impurity elements and improve the quality of high-alumina refractory materials.

[0075] (2) Effect of calcination time on element removal rate and alumina content

[0076] The secondary aluminum ash washed with water under the optimal water washing parameters in step (1) of Example 2 was subjected to a roasting experiment. Under the conditions of a heating rate of 6°C / min, a gas flow rate of 4L / min, and a roasting temperature of preferably 1300°C, at a roasting time of 1h, the removal rates of K and Na were 30.3% and 36.5%, respectively, and the aluminum oxide content was 83.4%; at a roasting time of 4h, the removal rates of K and Na were 43.0% and 45.4%, respectively, and the aluminum oxide content was 88.2%; at a roasting time of 5h, the removal rates of K and Na were 43.5% and 46.2%, respectively, and the aluminum oxide content was 88.3%.

[0077] Theoretically, the higher the temperature, the better the effect. According to the experimental results, the removal rate of alkali metals K and Na and the content of alumina in the roasted product at 1500°C compared with 1300°C roasting temperature were not significantly improved. The roasting time was extended from 4h to 5h, and there was no significant improvement in the removal of alkali metal elements K and Na and the content of alumina. In a system where various components coexist, the mixing of multiple substances will cause the melting and boiling points of the substances to be lower than those of pure substances. At high temperatures, some crystalline stones will decompose successively, which is conducive to element removal, but considering that the melting of Al at too high a temperature fills the gaps between the particles, making the secondary aluminum ash internally densified, and the dense oxide layer rapidly generated by AlN will also hinder the volatilization of salts such as NaCl and KCl. Excessive roasting time will increase energy consumption and cost. Therefore, the high-temperature roasting treatment method of secondary aluminum ash in the present invention can be obtained from the experimental process and test results of Example 4. The optimal parameters for high-temperature roasting of the present invention are: roasting temperature 1300°C, roasting time 4h.

[0078] Example 5

[0079] The optimal parameters of the method of wet water washing and high temperature roasting of secondary aluminum ash obtained through Examples 1 to 4 can save costs, reduce energy consumption and realize resource utilization of secondary aluminum ash. The optimal water-washed sample of secondary aluminum ash obtained under the optimal water washing parameters in Example 2 was applied to the roasting experiment of secondary aluminum ash, and a high-aluminum refractory material with alumina and magnesia-aluminum spinel as the main components was roasted under the optimal roasting parameters in Example 4.

[0080] The aluminum oxide content of the material prepared in this embodiment is ≥88%, which meets the aluminum oxide content (≥80%) requirement of LZ-80 physical and chemical index in GB / T 2988-2012; K 2The content of O is 0.06%, which meets the potassium oxide (K 2 O) content limit ≤ 0.5%; Na 2 The content of O is 0.28%, which meets the requirement of sodium oxide (Na 2 O) content limit ≤ 0.3%; fluorine and chlorine content have reached the limit values ​​specified in the implementation standard of "GB5085.3-2007" "Hazardous Waste Identification Standard Leaching Toxicity Identification".

Claims

1. A method for the combined treatment of secondary aluminum ash wet washing and high temperature roasting, characterized in that: The following steps are involved: (1) Pretreatment The secondary aluminum ash is screened and dry-milled to obtain secondary aluminum ash with uniform particle size; (2) Wet washing The secondary aluminum ash obtained in step (1) is mixed with a water washing liquid and washed with water to obtain a secondary aluminum ash water-washed sample; The washing liquid is ultrapure water or an aqueous solution of ammonium chloride; (3) High temperature roasting The secondary aluminum ash water-washed sample obtained in step (3) is subjected to high-temperature roasting to obtain a high-aluminum refractory material; The high temperature calcination temperature is 700-1500°C and the calcination time is 1-5h.

2. The method for combined treatment of secondary aluminum ash wet washing and high temperature roasting as claimed in claim 1, characterized in that: In step (1), screening refers to: passing the secondary aluminum ash through a 60-mesh standard sieve; and controlling the speed of the ball mill for dry ball milling to be 200 to 400 r / min and the time to be 10 to 60 min.

3. The method for combined treatment of secondary aluminum ash wet washing and high temperature roasting as claimed in claim 1, characterized in that: In step (2), the mass fraction of the aqueous solution of ammonium chloride is 5 to 20%.

4. The method for combined treatment of secondary aluminum ash wet washing and high temperature roasting as claimed in claim 1, characterized in that: In step (2), the solid-liquid ratio of the secondary aluminum ash to the water washing liquid is 1:1-5, g / mL.

5. The method for combined treatment of secondary aluminum ash wet washing and high temperature roasting as claimed in claim 1, characterized in that: In step (2), the water washing temperature is 10 to 100°C.

6. The method for combined treatment of secondary aluminum ash wet washing and high temperature roasting as claimed in claim 1, characterized in that: In step (2), the washing time is 1 to 5 hours.

7. The method for combined treatment of secondary aluminum ash wet washing and high temperature roasting as claimed in claim 1, characterized in that: In step (2), the water washing stirring speed is 100 to 1000 r / min.

8. The method for combined treatment of secondary aluminum ash wet washing and high temperature roasting as claimed in claim 1, characterized in that: In step (2), the mass fraction of the aqueous solution of ammonium chloride is 15%; the solid-liquid ratio of the secondary aluminum ash to the water washing liquid is 1:3, g / mL; the water washing temperature is 60° C.; the water washing time is 3 hours; and the water washing stirring speed is 600 r / min.

9. The method for combined treatment of secondary aluminum ash wet washing and high temperature roasting as claimed in claim 1, characterized in that: In step (3), the calcination temperature is 1300° C. and the calcination time is 4 h.

10. The method for combined treatment of secondary aluminum ash wet washing and high temperature roasting as claimed in claim 1, characterized in that: In step (3), the calcination atmosphere is air, and the gas flow rate is 4 L / min.

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