阅读说明：本技术 一种协同处理铝灰、炭渣及脱硫石膏渣的方法 (Method for cooperatively treating aluminum ash, carbon slag and desulfurized gypsum slag ) 是由 林艳 崔焱 王皓逸 马路通 邓聪 于 2021-05-25 设计创作，主要内容包括：本发明公开一种协同处理铝灰、炭渣和脱硫石膏渣的方法,通过联合浸出铝灰和炭渣,利用两种物料中的含氟和含铝组分配比,产出氟化铝、氧化铝和α-Al-2O-3阳极涂层产品,并利用浸出过程产生的芒硝废液和铝电解烟气脱硫石膏渣反应制备硫酸钙晶须。本方法氟和铝有价元素回收率高(≥90％)、主产品AlF-3和Al-2O-3混合料纯度≥98％,可用于铝电解过程,副产物硫酸钙晶须和α-Al-2O-3阳极涂层品质好,整体技术利润附加值高、试剂消耗和能耗小,有利于保护生态环境,有效降低了材料消耗和成本,提高固废物料回收的经济效益和环境效益。(The invention discloses a method for cooperatively treating aluminum ash, carbon slag and desulfurized gypsum slag, which is characterized in that aluminum ash and carbon slag are jointly leached, and aluminum fluoride, aluminum oxide and alpha-Al are produced by utilizing the proportion of fluorine-containing components and aluminum-containing components in the two materials 2 O 3 And preparing the calcium sulfate whisker by using the reaction of mirabilite waste liquid generated in the leaching process and the aluminum electrolysis flue gas desulfurization gypsum slag. The method has high recovery rate (more than or equal to 90 percent) of fluorine and aluminum valuable elements and the AlF as a main product 3 And Al 2 O 3 The purity of the mixture is more than or equal to 98 percent, and the mixture can be used for the aluminum electrolysis process, by-products of calcium sulfate whisker and alpha-Al 2 O 3 The anode coating has good quality, high added value of the whole technology profits, and low reagent consumption and energy consumption, is beneficial to protecting the ecological environment, effectively reduces the material consumption and cost, and improves the economic benefit and the environmental benefit of solid waste material recovery.)

1. A method for cooperatively treating aluminum ash, carbon slag and desulfurized gypsum slag is characterized by comprising the following steps:

(1) grinding the aluminum ash, mixing the ground aluminum ash with water, carrying out water leaching treatment, and filtering to obtain a water leaching solution and a water leaching aluminum ash material;

(2) crushing the carbon slag, and grinding the carbon slag to a preset granularity;

(3) preparing concentrated sulfuric acid, aluminum salt and water into a leaching solution;

(4) mixing the water-soaked aluminum ash obtained in the step (1) with the carbon residue with the preset granularity obtained in the step (2), then mixing the mixture with the leaching solution obtained in the step (3), then leaching, and performing liquid-solid separation on the slurry obtained by leaching to obtain the leaching solution and leaching residue;

(5) mixing the leachate obtained in the step (4) with the water leaching solution obtained in the step (1), adding alkali to adjust the pH value, then preserving heat and aging, and filtering to obtain a fluorine-aluminum precursor and a precipitated solution;

(6) calcining the leaching residue obtained in the step (4), and then carrying out acid washing to remove impurities to obtain alpha-Al₂O₃；

(7) Calcining the fluorine aluminum precursor obtained in the step (5) to obtain aluminum fluoride and aluminum oxide;

(8) and (3) mixing the precipitated liquid obtained in the step (5) with desulfurized gypsum slag, adjusting the pH value, adding a crystal growth substance and a surfactant, and carrying out hydrothermal preparation to obtain the calcium sulfate whisker.

2. The method for cooperatively treating the aluminum ash, the carbon slag and the desulfurized gypsum slag according to claim 1, wherein in the step (1), the aluminum ash is ground in a dry grinding mode, the grinding granularity is controlled to be-100 meshes to-325 meshes, the water immersion temperature is normal temperature, and the solid-to-solid ratio of the leaching solution is 1-3 cm³The leaching time is more than or equal to 2 hours per gram.

3. The method for co-processing aluminum ash, carbon slag and desulfurized gypsum slag according to claim 1, wherein in the step (2), the crushed particle size of the carbon slag is controlled to be-10 mm, the grinding manner is wet grinding, and the grinding is carried out until the predetermined particle size is-200 mesh to-325 mesh.

4. The method for co-processing aluminum ash, carbon slag and desulfurized gypsum slag according to claim 1, wherein in step (3), the sulfuric acid concentration of the leachate prepared from concentrated sulfuric acid, aluminum salt and water is 1-2mol/L, the aluminum salt is one or more of aluminum sulfate, aluminum chloride, aluminum nitrate and sodium metaaluminate, and the leachate is one or more of aluminum sulfate, aluminum chloride, aluminum nitrate and sodium metaaluminateMiddle Al³⁺The concentration is 2-3 g/L.

5. The method for co-processing the aluminum ash, the carbon slag and the desulfurized gypsum slag according to claim 1, wherein in the step (4), the water-soaked aluminum ash and the carbon slag are mixed according to a mass ratio of 2: 1-3: 1, mixing the mixed materials with a leaching solution according to a liquid-solid ratio of 5-10 cm³And mixing the slurry per gram, wherein the leaching temperature is 35-45 ℃, and the leaching time is not less than 24 hours.

6. The method for co-processing aluminum ash, carbon slag and desulfurized gypsum slag according to claim 1, wherein in step (5), the alkali is selected from one or more of aluminum hydroxide and sodium aluminate, the alkali is added to a pH of 5.0-5.5, the aging temperature is 80-90 ℃, and the aging time is ≧ 4 h.

7. The method for co-processing the aluminum ash, the carbon slag and the desulfurized gypsum slag according to claim 1, wherein in the step (6), the calcination temperature is 700-1000 ℃, the calcination atmosphere is air, and the concentration of the acid is 1-2 mol/L.

8. The method for co-processing the aluminum ash, the carbon slag and the desulfurized gypsum slag according to claim 1, wherein in the step (7), the calcination temperature of the fluorine-aluminum precursor is 485-500 ℃, the calcination atmosphere is air, and the calcination time is not less than 2 h.

9. The method for cooperatively treating the aluminum ash, the carbon slag and the desulfurized gypsum slag according to claim 1, wherein in the step (8), the precipitated liquid and the desulfurized gypsum slag are mixed and slurried until the mass fraction of the slurry is 5-10%, the pH value of the slurry is controlled to be 9.8-10.1, the hydrothermal temperature is 120-130 ℃, and the hydrothermal time is 1-2 hours.

10. The method for co-processing aluminum ash, carbon slag and desulfurized gypsum slag according to claim 1, wherein in step (8), the crystal growth substance is one or more of magnesium salt and potassium salt; the surfactant is one or more of potassium dodecyl sulfate and bromocetyl pyridine.

Technical Field

The invention relates to the technical field of solid waste recovery, in particular to a high-valued recovery technology for cooperatively treating aluminum ash, carbon slag and desulfurized gypsum slag produced in an aluminum smelting process.

Background

Aluminum ash, carbon slag and desulfurized gypsum slag are the main solid wastes generated in the aluminum smelting process. The aluminum ash is slag and floating skin produced in the process of refining aluminum materials by smelting aluminum liquid, aluminum ingots and secondary aluminum, generally, about 20-40kg of aluminum ash is produced by processing one ton of raw aluminum, the main components of the aluminum ash are metallic aluminum and aluminum oxide (the mass accounts for about 30-70%, and a part of the aluminum ash is alpha-Al₂O₃Morphology), silica, iron oxide, and also small amounts of aluminum nitride, aluminum carbide, and chloride salts. The carbon slag is mainly fluorine-containing solid waste produced in the aluminum smelting process, and mainly comprises cryolite, carbon, cryolite, a small amount of aluminum oxide and calcium fluoride. According to statistics, 5-15 kg of carbon slag is discharged when one ton of raw aluminum is produced. The desulfurized gypsum residue is Ca (OH) adopted in the aluminum electrolysis process₂The waste residue generated by absorbing sulfur-containing flue gas generally contains more than 70 percent of Ca (OH)₂And a small amount of calcium sulfate.

The recovery process of aluminum ash is mainly divided into wet chemical method for preparing aluminum-containing material, high temperature sintering method for preparing refractory material, building material as main raw material, etc. according to the treatment mode and application. The wet chemical process of preparing aluminum containing material includes treating secondary aluminum ash with sodium hydroxide, sulfuric acid, hydrochloric acid or nitric acid solution as medium and through pressure leaching, dissolving simple substance aluminum and soluble aluminum oxide in the aluminum ash to form leached slurry, and solid-liquid separation to obtain leached slag and aluminum containing solution. The aluminium-containing solution can be treated in series to prepare products such as aluminium oxide, aluminium sulphate, aluminium chloride and the like. The leached slag can be used as the main raw material for producing ceramics and building materials after being washed and dried. The method has the main defects that the recycling of nitride and fluoride is not considered in the leaching process, the gas generated in the treatment process still has bad influence on the environment, the process circulation capability is poor, and the production cost is higher. The method for preparing the refractory material by the high-temperature sintering method is to prepare the qualified refractory materials such as brown fused alumina, magnesium aluminate spinel or Sialon and the like by mixing materials according to the requirements of the prepared product and sintering under the high-temperature condition. The performance of the prepared refractory material can meet the industrial requirement, and the prepared refractory material has low preparation cost and obvious economic benefit. However, in the process of preparing the refractory material, the aluminum ash needs to be washed to remove nitrogen firstly, so that the hydrolysis of nitrogen-containing substances in the subsequent use process is avoided, and the influence of the nitrogen-containing substances on the performance of products is eliminated. The prior art for removing nitrogen adopts a hot water washing mode, but the hot water washing nitrogen removal efficiency is low, the nitrogen removal effect is poor, and the process requirements cannot be met. The method for preparing the building material by taking the aluminum ash as the main raw material and adding additives such as quartz, clay and the like capable of reducing the sintering temperature to produce the building material. The obtained ganged brick has good porosity and compressive strength, and is an ideal substitute of the traditional clay sintered brick. The calcium aluminate cement can also be prepared by taking aluminum ash, aluminum sludge and alumina as raw materials, and various performance indexes of the prepared calcium aluminate cement can reach the international cement standard. However, the aluminum ash contains a certain amount of chloride, heavy metal, fluoride and the like, which affect the strength, corrosion resistance and other properties of the product, especially, hydrolysis of aluminum nitride has a bad influence on the atmospheric environment, and the aluminum ash can be used only after being pretreated, so that the recycling cost and technical difficulty of the aluminum ash are increased to a certain extent, and the popularization and application of the aluminum ash in the field of buildings are hindered.

The existing methods for recovering carbon slag mainly comprise a flotation method, an acidolysis method, a pyrogenic decarburization method, an alkali-acid two-stage leaching method process, a method for preparing aluminum fluoride and aluminum oxide by decarbonizing and removing sodium from carbon slag. The flotation method comprises the steps of crushing and grinding carbon slag to 20-60 meshes, adding water, a collecting agent and a foaming agent into carbon slag particles to prepare ore pulp, sequentially carrying out a closed flow of rough concentration, scavenging and fine concentration on the ore pulp, and filtering, dehydrating and drying bottom flow to obtain a regenerated cryolite product; filtering and dehydrating the overflow to obtain carbon powder blocks; the fluoride salt recovery of the process is about 85%. Acid hydrolysisThe method is characterized in that organic acid is adopted to convert fluoride salt in the carbon residue into HF for volatilization, then an alkaline solution is used for absorbing the HF, and the recovery rate of the fluoride salt can reach 90%. The fire method for removing carbon is that natural gas and other fuels are blown into a rotary kiln or a converter to be heated to 700-1300 ℃ so as to oxidize carbon into CO₂Removing with electrolyte, and optionally adding NaF and CaF during decarbonization₂、NaCl、Al₂O₃And the dispersant is used for reducing the reaction temperature, and the dosage of the dispersant is about 5-20% of that of the carbon residue according to different components. The alkali-acid two-stage leaching method is characterized in that 2.5mol/L NaOH is adopted in the first stage, and the liquid-solid ratio is 4.5cm³Leaching cryolite and Al in the carbon residue at 100 DEG C₂O₃Filtering to obtain alkaline leaching solution and alkaline leaching residue, and performing second stage with 9.7mol/L hydrochloric acid at liquid-solid ratio of 4cm³The CaF in the filtrate is leached out at 90 DEG C₂Filtering to obtain acid leaching solution, mixing the first stage alkali leaching solution and the second stage acid leaching solution, adjusting pH value to 9, aging at 70 deg.C for 3 hr, and precipitating to obtain cryolite. The carbon residue decarburizing and sodium removing method for preparing aluminum fluoride and aluminum oxide is characterized in that electrolytic aluminum carbon residue is crushed into fine particles with the particle size of less than 3mm, decarburizing agents are added into the carbon residue, the mixture is uniformly mixed to obtain a No. 1 mixture, a high-temperature furnace is added in an air atmosphere for heating treatment to obtain coarse fluoride A, the sodium removing agents are added into the coarse fluoride A, the mixture is uniformly mixed and then added into the high-temperature furnace for heating treatment for 2 sections to obtain coarse fluoride B, the coarse fluoride B is subjected to industrial pure water leaching to remove sodium salt, and then aluminum fluoride and aluminum oxide products are obtained through drying. At present, no applicable and cheap disposal method for the desulfurized gypsum residue is available, and the method is mainly stockpiling treatment.

The solid waste disposal methods for aluminum smelting process are all used for separately disposing or recycling single solid waste, and linkage recycling is not performed on various solid wastes, and the existing methods have the defects of complex flow, low recovery rate of valuable elements, low product purity and added value, high reagent consumption and energy consumption and the like.

Therefore, there is a need to solve the above-mentioned drawbacks of the prior art.

Disclosure of Invention

In view of the above-mentioned deficiencies of the prior art, it is an object of the present invention to provideA process for recovering the aluminium ash, carbon slag and desulfurized gypsum slag generated by smelting aluminium features that the aluminium ash and carbon slag are jointly leached out to obtain aluminium fluoride, aluminium oxide and alpha-Al₂O₃And (3) preparing a high-valued calcium sulfate whisker by reacting mirabilite waste liquid generated in the leaching process with desulfurized gypsum slag.

The technical scheme of the invention is as follows:

referring to fig. 1, the method for co-processing aluminum ash, carbon slag and desulfurized gypsum slag provided by the invention comprises the following steps:

(1) grinding the aluminum ash, mixing the ground aluminum ash with water, carrying out water leaching treatment, and filtering to obtain a water leaching solution and a water leaching aluminum ash material;

(2) crushing the carbon slag, and grinding the carbon slag to a preset granularity;

(3) preparing concentrated sulfuric acid (the concentration can be 95-98%), aluminum salt and water into leachate;

(4) mixing the water-soaked aluminum ash obtained in the step (1) with the carbon residue with the preset granularity obtained in the step (2), then mixing the mixture with the leaching solution obtained in the step (3), then leaching, and performing liquid-solid separation on the slurry obtained by leaching to obtain the leaching solution and leaching residue;

(5) mixing the leachate obtained in the step (4) with the water leaching solution obtained in the step (1), adding alkali to adjust the pH value, then preserving heat and aging, and filtering to obtain a fluorine-aluminum precursor and a precipitated solution;

(6) calcining the leaching residue obtained in the step (4), and then carrying out acid washing to remove impurities to obtain alpha-Al₂O₃；

(7) Calcining the fluorine aluminum precursor obtained in the step (5) to obtain aluminum fluoride and aluminum oxide;

(8) and (3) mixing the precipitated liquid obtained in the step (5) with desulfurized gypsum slag, adjusting the pH value, adding a crystal growth substance and a surfactant, and carrying out hydrothermal preparation to obtain the calcium sulfate whisker.

Optionally, step (1) specifically includes: grinding the aluminum ash, mixing the ground aluminum ash with industrial water, mechanically stirring and soaking in water for several hours to decompose aluminum nitride and aluminum carbide possibly existing in the aluminum ash, simultaneously dissolving and washing out soluble fluoride salt and chloride salt, and filtering to obtain a water soaking solution and a water soaking aluminum ash material.

Optionally, the aluminum ash is ground to-100 mesh to-325 mesh using dry grinding.

Further, the water immersion temperature is normal temperature (such as 25-35 ℃), and the leaching liquid-solid ratio (liquid-solid ratio of water to aluminum ash) is 1-3 cm³The leaching time is more than or equal to 2 hours, such as 2 hours, 3 hours, 4 hours, 5 hours and the like.

In the step (2), optionally, the carbon slag is crushed to-10 mm, and then ore grinding is carried out in a wet grinding mode, wherein the predetermined particle size after ore grinding is-200 meshes to-325 meshes.

In the step (3), the concentration of sulfuric acid in the leaching solution prepared from concentrated sulfuric acid, aluminum salt and water is 1-2 mol/L;

further, the aluminum salt may be one or more of aluminum sulfate, aluminum chloride, aluminum nitrate, and sodium metaaluminate.

Further, Al in the leachate³⁺The concentration is 2-3g/L, i.e. the amount of aluminum salt added is in accordance with Al³⁺The concentration is 2-3 g/L.

In the step (4), the water-soaked aluminum ash and the carbon slag are mixed according to the mass ratio of 2: 1-3: 1, mixing (namely batching), wherein the mixed material and the leaching solution are 5-10 cm according to the liquid-solid ratio³And mixing the slurry per gram.

Further, the leaching temperature is 35-45 ℃, and the leaching time is not less than 24h, such as 24h, 25h, 26h, 27h, 28h and the like.

In the step (5), water such as fluoride salt and chloride salt which are soluble in the aluminum ash is leached out by industrial water in the step (1), and the obtained water leaching solution and the acid leaching solution in the step (4) are mixed to precipitate the fluorine-aluminum precursor. Because the main component of the soluble fluoride salt in the aluminum ash is sodium fluoride, if the part of the free fluoride ions directly enter the acid leaching system in the step (4), the free fluoride ions are easy to volatilize and lose due to the long acid leaching time (over 24 hours) and the acidic condition.

Optionally, an alkali solution is added to adjust the pH value, and the alkali solution used can be one or more of an aluminum hydroxide solution, a sodium aluminate solution and the like.

Further, an alkali is added to a pH of 5.0 to 5.5, i.e., a pH at the end of the neutralization precipitation is controlled to 5.0 to 5.5.

Further, the aging temperature is 80-90 ℃, and the aging time is not less than 4h, such as 4h, 5h, 6h, 7h, 8h, 9h and the like.

In the step (6), the leaching residue obtained in the step (4) is calcined at high temperature to remove carbon, and then acid solution is adopted to wash and remove impurities, so that alpha-Al which can be used for preparing aluminum electrolysis anode coating is obtained₂O₃And (5) producing the product.

Further, the high-temperature calcination decarbonization temperature of the leached residues is 700-1000 ℃, and the calcination atmosphere is air.

Furthermore, the concentration of the acid (such as dilute sulfuric acid) for washing and removing impurities is 1-2 mol/L.

And (7) before calcining the fluorine-aluminum precursor obtained in the step (5), drying the fluorine-aluminum precursor, wherein the drying temperature of the fluorine-aluminum precursor is 60-80 ℃, and the atmosphere is air.

Further, the calcination temperature of the fluorine-aluminum precursor is 485-500 ℃, the calcination atmosphere is air, and the calcination time is more than or equal to 2 hours, such as 2 hours, 3 hours, 4 hours, 5 hours, 6 hours and the like.

Optionally, the step (8) specifically includes: and (3) mixing the precipitated liquid obtained in the step (5) with desulfurized gypsum slag, stirring, adjusting the pH value, adding a crystal growth substance and a surfactant, performing hydrothermal aging, and finally performing centrifugal filtration to obtain the calcium sulfate whisker.

Optionally, mixing the precipitated liquid and the desulfurized gypsum slag, and pulping until the mass fraction of the slurry is 5-10%.

Further, the pH value of the slurry is controlled to be 9.8-10.1, and the hydrothermal temperature is 120-130 ℃.

Furthermore, the stirring speed is 150-200 r/min, and the hydrothermal time is 1-2 h.

Furthermore, the crystal growth promoter may be one or more of magnesium salt (such as magnesium sulfate), potassium salt (such as potassium sulfate), etc., and the addition amount is 0.04-0.10 mol/L.

Further, the surfactant can be one or more of potassium dodecyl sulfate, bromocetyl pyridine and the like, and the addition amount of the surfactant is 0.1-0.5 percent by mass of the desulfurized gypsum residue.

The reaction equation involved in the above treatment method is:

the main reaction of the aluminum ash and the carbon slag in the water leaching process is as follows:

2Al+3H₂O→2Al₂O₃+3H₂↑

Al₄C₃+6H₂O→2Al₂O₃+3CH₄↑

2AlN+3H₂O→Al₂O₃+2NH₃↑

NaF_(s)→NaF_(l)

MeCl_n(s)→MeCl_n(l)(Me is mainly an alkali metal, an alkaline earth metal, such as Na, K, etc.)

The main reactions of the aluminum ash and the carbon slag during the mixed leaching are as follows:

Al₂O₃+6H⁺→2Al³⁺+3H₂O

Al₂O₃+4F^-+6H⁺→2AlF₂ ⁺+3H₂O

4Al³⁺+2Na₃AlF₆→6Na⁺+6AlF₂ ⁺

CaF₂+2Al³⁺→Ca²⁺+2AlF₂ ⁺

AlF₃+2Al³⁺→3AlF₂ ⁺

Al₂O₃+6H⁺→2Al³⁺+3H₂O

neutralizing and precipitating the fluorine aluminum precursor:

0.76Al³⁺+3.24AlF₂ ⁺+7.52H₂O→2Al₂F_3.24(OH)_2.76·H₂O↓+5.52H⁺

and (3) calcining:

3Al₂F_3.24(OH)_2.76·H₂O→3.24AlF₃+1.38Al₂O₃+7.14H₂O

the hydrothermal preparation process of the calcium sulfate whisker comprises the following steps:

Ca(OH)₂+Na₂SO₄→CaSO₄↓+2NaOH

has the advantages that: the invention provides a high-valued recovery technology for cooperatively treating aluminum ash, carbon slag and desulfurized gypsum slag produced in an aluminum smelting process, in particular to a technology for producing aluminum fluoride, aluminum oxide and alpha-Al by jointly leaching the aluminum ash and the carbon slag and utilizing the proportion of fluorine-containing components and aluminum-containing components in the two materials₂O₃And (3) preparing a calcium sulfate whisker by using a mirabilite waste liquid (namely the precipitated liquid obtained in the step (5)) generated in the leaching process and the desulfurized gypsum slag. The method has high recovery rate (more than or equal to 90%) of fluorine and aluminum valuable elements, and the produced product has high purity (AlF as main product)₃And Al₂O₃The purity of the mixture is more than or equal to 98 percent) and can be used for the aluminum electrolysis process, by-products of calcium sulfate whisker and alpha-Al₂O₃The anode coating has good quality, high added value of the whole technology profits, and low reagent consumption and energy consumption, is beneficial to protecting the ecological environment, effectively reduces the material consumption and cost, and improves the economic benefit and the environmental benefit of solid waste material recovery.

Drawings

FIG. 1 is a process flow diagram of the present invention for the synergistic recovery of aluminum ash, carbon slag and desulfurized gypsum slag from an aluminum smelting process;

FIG. 2 is an XRD pattern of the precipitated fluoroaluminium precursor of example 1;

FIG. 3 is an SEM photograph of a precipitated fluoroaluminium precursor of example 1;

FIG. 4 is an XRD pattern of the product obtained after calcination of the aluminum fluoride precursor of example 1;

FIG. 5 shows the anodic coating α -Al prepared in example 1₂O₃The XRD pattern of the product;

FIG. 6 is an SEM image of calcium sulfate whiskers prepared in example 1;

FIG. 7 is an XRD pattern of the precipitated fluoroaluminium precursor of example 2;

FIG. 8 is an SEM photograph of a precipitated fluoroaluminium precursor of example 2;

FIG. 9 is an XRD pattern of the product obtained after calcination of the aluminum fluoride precursor of example 2;

FIG. 10 is an SEM photograph of a precipitated fluoroaluminium precursor of example 3;

fig. 11 is an XRD pattern of the product obtained after calcination of the aluminum fluoride precursor of example 3.

Detailed Description

The invention provides a method for synergistically recovering aluminum ash, carbon slag, desulfurized gypsum slag and other solid waste materials generated in an aluminum smelting process, and the invention is further described in detail below in order to make the purpose, technical scheme and effect of the invention clearer and more clear. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example treated feedstock

The method takes aluminum ash, carbon slag and desulfurized gypsum slag produced by a certain aluminum smelting plant in Yunnan as raw materials, and the main components of the materials are respectively as follows through fluorescence spectrum analysis:

TABLE 1 aluminum ash principal Components

TABLE 2 carbon residue main Components

TABLE 3 desulfurized Gypsum slag major Components

Example 1

(1) 50g of aluminum ash (ingredients are shown in Table 1) is dry-ground to-100 meshes and then mixed with industrial water according to the liquid-solid ratio of 2cm³Mixing the mixture in the concentration ratio of/g, mechanically stirring and leaching for 2 hours at normal temperature to ensure that aluminum nitride possibly existing in the mixture is mixed with the mixed solutionDecomposing the aluminum carbide, simultaneously dissolving out soluble fluoride salt and chloride salt, and filtering the leached slurry to obtain a water leaching solution and a water leaching aluminum ash material;

(2) crushing 20g of carbon slag (the components are shown in the table 2) to-10 mm, and then grinding the carbon slag by adopting a wet grinding mode, wherein the granularity of the ground carbon slag is controlled to-325 meshes;

(3) 35mL of industrial concentrated sulfuric acid (98% concentration), 10g of aluminum sulfate (Al)₂(SO₄)₃·18H₂O) and 400mL of water are prepared into leaching solution;

(4) mixing the water-leached aluminum ash obtained in the step (1) with the carbon residue obtained in the step (2), then mixing the mixture with the leaching solution prepared in the step (3), then leaching for 24 hours at 38 ℃, and performing liquid-solid separation on the leached slurry to obtain the leaching solution and leaching residues;

(5) mixing the leachate obtained in the step (4) with the water leaching solution obtained in the step (1), heating to 90 ℃, adding a saturated sodium hydroxide solution to adjust the pH value of the solution to 5.5, then preserving heat and aging at 90 ℃ for 4 hours, and filtering to obtain a fluorine-aluminum precursor and a precipitated solution;

(6) calcining the leaching residue obtained in the step (4) at 800 ℃ for 4 hours in air atmosphere to remove carbon in the leaching residue, washing the decarburized material by using 1mol/L dilute sulfuric acid solution to remove impurities, and obtaining the alpha-Al for preparing the aluminum electrolysis anode coating₂O₃Producing a product;

(7) drying the aluminum fluoride precursor obtained in the step (5) at 60 ℃ in air atmosphere, and calcining the dried aluminum fluoride precursor at 485 ℃ in air atmosphere for 2 hours to obtain aluminum fluoride and aluminum oxide products;

(8) and (3) mixing the precipitated liquid obtained in the step (5) with the desulfurized gypsum slag, controlling the mass fraction of slurry to be 5%, controlling the stirring speed to be 200r/min, heating to 120 ℃, then adopting a saturated sodium hydroxide solution to adjust the pH value to be 10, adding 0.04mol/L magnesium sulfate as a crystal growth substance, adding dodecyl potassium sulfate as a surfactant according to the proportion that the mass percentage of the surfactant to the desulfurized gypsum slag is 0.1%, performing hydrothermal aging at 120 ℃ for 2 hours, and finally performing centrifugal filtration to obtain the calcium sulfate whisker.

FIG. 2 is an XRD pattern of the precipitated fluoroaluminium precursor of example 1;

FIG. 3 is an SEM photograph of a precipitated fluoroaluminium precursor of example 1;

FIG. 4 is an XRD pattern of the product obtained after calcination of the aluminum fluoride precursor of example 1;

FIG. 5 shows the anodic coating α -Al prepared in example 1₂O₃The XRD pattern of the product;

fig. 6 is an SEM image of calcium sulfate whiskers prepared in example 1.

Example 2

(1) 50g of aluminum ash (ingredients are shown in Table 1) is dry-ground to-200 meshes and then mixed with industrial water according to the liquid-solid ratio of 2cm³Mixing/g, mechanically stirring and leaching for 3 hours at normal temperature to decompose aluminum nitride and aluminum carbide possibly existing in the mixture, dissolving and washing out soluble fluoride salt and chloride salt, and filtering the leached slurry to obtain a water leaching solution and a water leaching aluminum ash;

(2) crushing 20g of carbon slag (the components are shown in the table 2) to-10 mm, and then grinding the carbon slag by adopting a wet grinding mode, wherein the granularity of the ground carbon slag is controlled to-200 meshes;

(3) 30mL of industrial concentrated sulfuric acid (98% concentration), 15g of aluminum sulfate (Al)₂(SO₄)₃·18H₂O) and 700mL of water are prepared into leachate;

(4) mixing the water-soaked aluminum ash obtained in the step (1) with the carbon residue obtained in the step (2), then mixing the mixture with the leaching solution prepared in the step (3), leaching the mixture for 24 hours at 40 ℃, and performing liquid-solid separation on the leached slurry to obtain the leaching solution and leaching residues;

(5) mixing the leachate obtained in the step (4) with the water leaching solution obtained in the step (1), heating to 90 ℃, adding a saturated sodium hydroxide solution to adjust the pH value of the solution to 5.5, then preserving heat and aging at 90 ℃ for 4 hours, and filtering to obtain a fluorine-aluminum precursor and a precipitated solution;

(6) calcining the leaching residue obtained in the step (4) at 900 ℃ for 4 hours in air atmosphere to remove carbon in the leaching residue, washing the decarburized material by using 1mol/L dilute sulfuric acid solution to remove impurities, and obtaining the alpha-Al for preparing the aluminum electrolysis anode coating₂O₃Producing a product;

(7) drying the aluminum fluoride precursor obtained in the step (5) at 60 ℃ in an air atmosphere, and calcining the dried aluminum fluoride precursor for 2 hours at 500 ℃ in the air atmosphere to obtain aluminum fluoride and aluminum oxide products;

(8) and (3) mixing the precipitated liquid obtained in the step (5) with the desulfurized gypsum slag, controlling the mass fraction of slurry to be 5%, controlling the stirring speed to be 150r/min, heating to 120 ℃, then adopting a saturated sodium hydroxide solution to adjust the pH value to be 10, adding 0.04mol/L magnesium sulfate as a crystal growth substance, adding dodecyl potassium sulfate as a surfactant according to the proportion that the mass percentage of the surfactant to the desulfurized gypsum slag is 0.1%, performing hydrothermal aging at 120 ℃ for 2 hours, and finally performing centrifugal filtration to obtain the calcium sulfate whisker.

FIG. 7 is an XRD pattern of the precipitated fluoroaluminium precursor of example 2;

FIG. 8 is an SEM photograph of a precipitated fluoroaluminium precursor of example 2;

fig. 9 is an XRD pattern of the product obtained after calcination of the aluminum fluoride precursor of example 2.

Example 3

(1) 40g of aluminum ash (ingredients are shown in Table 1) is dry-ground to-200 meshes and then mixed with industrial water according to the liquid-solid ratio of 1cm³Mixing/g, mechanically stirring and leaching for 4 hours at normal temperature to decompose aluminum nitride and aluminum carbide possibly existing in the mixture, dissolving and washing out soluble fluoride salt and chloride salt, and filtering the leached slurry to obtain a water leaching solution and a water leaching aluminum ash;

(2) crushing 20g of carbon slag (the components are shown in the table 2) to-10 mm, and then grinding the carbon slag by adopting a wet grinding mode, wherein the granularity of the ground carbon slag is controlled to-325 meshes;

(3) 30mL of industrial concentrated sulfuric acid (95% concentration), 10g of aluminum sulfate (Al)₂(SO₄)₃·18H₂O) and 700mL of water are prepared into leachate;

(4) mixing the water-soaked aluminum ash obtained in the step (1) with the carbon residue obtained in the step (2), then mixing the mixture with the leaching solution prepared in the step (3), leaching for 26 hours at 40 ℃, and performing liquid-solid separation on the leached slurry to obtain the leaching solution and leaching residues;

(5) mixing the leachate obtained in the step (4) with the water leaching solution obtained in the step (1), heating to 90 ℃, adding a saturated sodium hydroxide solution to adjust the pH value of the solution to 5.5, then preserving heat and aging at 90 ℃ for 4 hours, and filtering to obtain a fluorine-aluminum precursor and a precipitated solution;

(6) calcining the leaching residue obtained in the step (4) for 4 hours at 850 ℃ in air atmosphere to remove carbon in the leaching residue, washing the decarburized material by using 1mol/L dilute sulfuric acid solution to remove impurities, and obtaining the alpha-Al for preparing the aluminum electrolysis anode coating₂O₃Producing a product;

(7) drying the aluminum fluoride precursor obtained in the step (5) at 60 ℃ in an air atmosphere, and calcining the dried aluminum fluoride precursor for 3 hours at 500 ℃ in the air atmosphere to obtain aluminum fluoride and aluminum oxide products;

(8) and (3) mixing the precipitated liquid obtained in the step (5) with the desulfurized gypsum slag, controlling the mass fraction of slurry to be 5%, controlling the stirring speed to be 200r/min, heating to 120 ℃, then adopting a saturated sodium hydroxide solution to adjust the pH value to be 9.8, adding 0.04mol/L magnesium sulfate as a crystal growth substance, adding dodecyl potassium sulfate as a surfactant according to the proportion that the mass percentage of the surfactant to the desulfurized gypsum slag is 0.1%, performing hydrothermal aging at 120 ℃ for 2 hours, and finally performing centrifugal filtration to obtain the calcium sulfate whisker.

FIG. 10 is an SEM photograph of a precipitated fluoroaluminium precursor of example 3;

fig. 11 is an XRD pattern of the product obtained after calcination of the aluminum fluoride precursor of example 3.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.