阅读说明：本技术 一种铝灰无害化处理的方法 (Harmless treatment method for aluminum ash ) 是由 陈湘清 唐剑 陈小松 陈黎军 彭助贵 于 2019-11-04 设计创作，主要内容包括：一种铝灰无害化处理的方法,包括以下步骤：(1)将铝灰和水混合,搅拌化浆,分级,得细颗粒料浆；或将分级后的铝灰和水混合,搅拌化浆,得细颗粒料浆；(2)加入浸取剂,浸出反应后,得非金属料浆；(3)将氧化料浆进行球磨脱氨,脱氨料浆经洗涤,过滤,洗涤,烘干,得无害化铝灰。本发明方法生产过程的安全系数高,且方法简单、成本低,适宜于工业化生产,所得无害化铝灰中的Al<Sub>2</Sub>O<Sub>3</Sub>的质量含量高达95%,氮化铝的质量含量≤0.02%,金属铝的质量含量≤0.01%,盐的质量含量≤0.2%,符合GB/T 24483-2009的铝土矿石标准,可作为净水剂、陶瓷、玻璃、耐火材料、建筑材料或电解铝的原料使用。(A method for harmlessly treating aluminum ash comprises the following steps: (1) mixing aluminum ash and water, stirring, pulping and grading to obtain fine particle slurry; or mixing the classified aluminum ash with water, stirring and slurrying to obtain fine particle slurry; (2) adding a leaching agent, and obtaining non-metal slurry after leaching reaction; (3) and (3) carrying out ball milling deamination on the oxidized slurry, washing, filtering, washing and drying the deaminated slurry to obtain harmless aluminum ash. The method has the advantages of high safety coefficient in the production process, simplicity, low cost and suitability for industrial production, and the obtained harmless Al in the aluminum ash 2 O 3 The mass content of the aluminum nitride is up to 95 percent, the mass content of the aluminum nitride is less than or equal to 0.02 percent, the mass content of the metal aluminum is less than or equal to 0.01 percent, the mass content of the salt is less than or equal to 0.2 percent, the aluminum nitride salt meets the standard of the bauxite ore of GB/T24483-2009, and the aluminum nitride salt can be used as a water purifying agent, ceramics, glass and refractory materialsAnd a raw material for building materials or electrolytic aluminum.)

1. The method for harmlessly treating the aluminum ash is characterized by comprising the following steps of:

(1) mixing aluminum ash and water, stirring, pulping and grading to obtain fine particle slurry; or mixing the classified aluminum ash with water, stirring and slurrying to obtain fine particle slurry;

(2) adding a leaching agent into the fine particle slurry obtained in the step (1), and obtaining non-metal slurry after leaching reaction;

(3) and (3) performing ball milling deamination on the nonmetal slurry obtained in the step (2), and washing, filtering, washing and drying the deamination slurry to obtain harmless aluminum ash.

2. The method for detoxifying aluminum ash according to claim 1, wherein: in the step (1), the aluminum ash comprises the following main components: 1-30% of simple substance aluminum, 30-90% of aluminum oxide, 1-30% of aluminum nitride, 0-10% of chlorine salt, 1-10% of fluorine salt, and the total percentage content is less than or equal to 100%; the solid-liquid ratio of the aluminum ash to the water is 1: 0.8-50; the temperature of the stirring and slurrying is 10-100 ℃, and the time is 10-360 min.

3. The method for detoxifying aluminum ash according to claim 1 or 2, wherein: in the step (1), the specific operation of the grading is as follows: grading for 1-120 min at 10-100 ℃ to obtain fine particle slurry or fine particles with the particle size of less than or equal to 325 meshes and the content of simple substance aluminum of less than or equal to 1%; carrying out filter pressing on coarse particle slurry obtained by grading and having a particle size of more than 325 meshes to obtain aluminum-containing powder paste; the grading is one or more of sedimentation grading, cyclone grading or screening grading.

4. The method for detoxifying aluminum ash according to any one of claims 1 to 3, wherein: in the step (2), the leaching agent is a mixture of ferric salt and/or cupric salt and ammonia water; the dosage of the ferric iron salt and/or the cupric salt is 0.8-3.0% of the dry basis weight of the fine particle slurry; the amount of the ammonia water is 0.3-5.0% of the dry basis weight of the fine particle slurry; the ferric iron salt is one or more of ferric chloride, ferric sulfate, ferric phosphate or ferric nitrate and hydrates thereof; the cupric salt is one or more of copper sulfate, copper chloride, copper nitrate or copper phosphate and hydrates thereof; the mass concentration of the ammonia water is 3-30%; the temperature of the leaching reaction is 10-100 ℃, and the time is 0.1-2.0 h.

5. The method for detoxifying aluminum ash according to any one of claims 1 to 4, wherein: in the step (3), the ball milling deamination is one-stage or two-stage ball milling deamination; the specific operation of the first-stage ball milling deamination is as follows: ball milling for 1-2 h at the temperature of less than 60 ℃ and the rotating speed of 20-40 r/min; when the two-stage ball milling deamination is carried out, the slurry after the first-stage ball milling is further classified, and the slurry with fine particles less than or equal to 325 meshes is subjected to the second-stage ball milling deamination for 1-20 hours at the temperature of 60-90 ℃ and the rotating speed of 20-40 r/min until the total concentration of ammonia and hydrogen in the released gas is less than 10 ppm; the grading temperature is 10-90 ℃, and the grading time is 1-120 min; the grading is one or more of sedimentation grading, cyclone grading or screening grading.

6. The method for detoxifying aluminum ash according to any one of claims 1 to 5, wherein: in the step (3), the equipment used for ball milling deamination is a closed system; controlling the volume concentration of hydrogen in a tail gas treatment system to be less than or equal to 3% and the volume concentration of ammonia to be less than or equal to 12% by means of induced air or inert gas in tail gas generated in the ball milling dehydrogenation process; absorbing the tail gas by using water or dilute sulfuric acid with the mass fraction of 1-10%; the equipment used for ball milling deamination is one or more of a ball mill, a Raymond mill, a rod mill, a vertical flour mill, a colloid mill, a stirring mill or a vibration mill.

7. The method for detoxifying aluminum ash according to any one of claims 1 to 6, wherein: in the step (3), salt is discharged from the filtrate obtained by filtering to obtain salt slag; the volume ratio of the deamination slurry to the washing water is 1: 0.5-3.0.

Technical Field

The invention relates to a method for treating aluminum ash, in particular to a method for harmlessly treating aluminum ash.

Background

The aluminum ash is a product of cooling and processing smelting slag generated in electrolytic aluminum or aluminum fusion casting production process, contains aluminum and a plurality of valuable elements, mainly consists of a mixture of metal aluminum, aluminum nitride, aluminum oxide, other metal oxides and salt flux, and has the following components in 6 series alloy aluminum ash of certain aluminum factories: al (Al)₂O₃54.71%，AlN 20%，MgO 6.21%，Fe₂O₃2.67%，KCl 3.69%，NaCl 4.28%，SiO₂6.64%，CaO 1.8%。

The aluminum ash contains high content of metallic aluminum and aluminum oxide, and is a precious renewable resource, the deliquescence of the metallic aluminum and the aluminum nitride in the aluminum ash can generate and release hydrogen and ammonia gas, the ammonia gas is a foul gas and is inflammable and explosive, and the salt flux is mainly chlorine salt and fluorine salt, wherein the content of soluble fluoride is high. Therefore, the aluminum ash belongs to dangerous waste according to the characteristics of leaching toxicity and hydrolysis reactivity of the aluminum ash, and if the aluminum ash is not treated properly, the aluminum ash can cause serious pollution to ecological environments such as land, water, air and the like.

At present, the treatment process of the aluminum ash comprises a pyrogenic method, a wet method and the like. The key point of harmless treatment of aluminum ash is to stabilize the aluminum ash and make the aluminum ash no longer have reactivity, the pyrogenic process can oxidize and decompose the aluminum nitride, and the wet process mainly utilizes water or a catalyst to decompose the aluminum nitride into ammonia gas.

CN106315643A discloses a method for producing calcium aluminate in a high temperature arc furnace by using waste aluminum ash and lime, CN205954085U discloses an apparatus for recovering metal aluminum from hot aluminum ash and preparing steelmaking auxiliary materials by using slag, CN108483927A discloses a method for sintering and producing nepheline glass ceramics by using aluminum ash, quartz sand and calcium powder as main raw materials, and CN105294135A discloses a method for directly preparing an aluminum spinel refractory material by using aluminum ash and a material prepared by the method. Although the leaching toxicity of fluoride ions and heavy metal ions of the aluminum ash can be solidified and stabilized by adding a reagent containing calcium ions, and due to the difference of the processes, the leaching toxicity of part of the aluminum ash cannot exceed the standard. However, the pyrogenic process has the problems of fluoride gas corrosion, high energy consumption and emission of nitrogen oxides generated by decomposition of aluminum nitride, and the reaction equation is as follows: 4Al +3O₂→2Al₂O₃，2AlN+2O₂→Al₂O₃+N₂O↑，4AlN+7O₂→2Al₂O₃+4NO₂↑。

CN105481044A discloses a method for preparing high-efficiency sewage treatment tablets by using aluminum ash as a raw material, CN105731508A discloses a method for preparing high-activity alumina powder by using aluminum ash, and CN106378012A discloses a poly aluminum ferric silicate and a method for preparing poly aluminum ferric silicate by using aluminum ash. However, the above-mentioned processes for producing water purifying agents by wet treatment do not address the problem that aluminum ash releases flammable and explosive hydrogen and ammonia when encountering acid, and the ammonia and the ammonium chloride residue generated by the neutralization of the ammonia and the acid can cause disqualification of ammonia nitrogen in the water purifying agents, and the reaction equation is as follows: 2Al +6HCl → 2AlCl₃+3H₂↑，AlN+3H₂O→Al(OH)₃+NH₃↑，NH₃+HCl→NH₄Cl。

CN105271327A discloses a method for harmless treatment and recycling of aluminum ash, and discloses a method for deamination by water leaching, but because the product formed by hydrolysis of aluminum nitride on the surface of aluminum ash particles is aluminum hydroxide, the aluminum ash particles are tightly wrapped, and continuous water permeation is prevented, the hydrolysis process of the aluminum ash is very long under natural conditions, and the aluminum hydroxide is an amphoteric compound, so the problem of slow reaction speed exists in deamination by water leaching, and an auxiliary agent is required to be adopted to dissolve the aluminum hydroxide on the surface of the aluminum ash, thereby accelerating the decomposition of the aluminum nitride.

CN105347361A discloses a method for treating aluminum ash by comprehensive utilization, which uses a catalyst capable of accelerating deamination, but the regenerated product contains catalyst residue and needs to be washed.

CN107597802A discloses a method for enhancing aluminum ash denitrification by a pressure regulating-hydrothermal cyclone process, which adopts hot water with the temperature of 80-150 ℃ and utilizes a hydrocyclone to accelerate the deamination process. Although the hydrolysis reaction of aluminum nitride can be accelerated in the initial stage, the aluminum nitride still cannot be completely decomposed because the water penetration is prevented by the envelope generated by hydrolysis and the reaction rate is reduced in the later stage.

CN108893615A discloses a method for recovering metallic aluminum from aluminum ash, which is to use a ball mill to wet-grind with water to deeply extract aluminum, but does not pay attention to the problems of ammonia and hydrogen (the explosion limit of hydrogen is 4.0-75.6%, the ammonia is 15.7-27.4%) which are flammable and explosive, gas collection and gas treatment, etc. caused by wet grinding.

CN106629774A discloses a method for harmlessly treating aluminum ash, which comprises the steps of dry-milling and extracting aluminum by using a ball mill, adding fine aluminum ash into a closed container, and soaking and deaminizing by using water. However, there are also problems of long deamination time and incomplete deamination.

In view of the above, it is desirable to find a method that can safely, quickly and thoroughly deaminate.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects in the prior art and provide a simple, safe, rapid and thorough deamination method for harmlessly removing Al in aluminum ash₂O₃The method has high quality content and low cost, and is suitable for the harmless treatment of the aluminum ash in industrial production.

The technical scheme adopted by the invention for solving the technical problems is as follows: a method for harmlessly treating aluminum ash comprises the following steps:

(1) mixing aluminum ash and water, stirring, pulping and grading to obtain fine particle slurry; or mixing the classified aluminum ash with water, stirring and slurrying to obtain fine particle slurry;

(2) adding a leaching agent into the fine particle slurry obtained in the step (1), and obtaining non-metal slurry after leaching reaction;

(3) and (3) performing ball milling deamination on the nonmetal slurry obtained in the step (2), and washing, filtering, washing and drying the deamination slurry to obtain harmless aluminum ash.

Preferably, in the step (1), the aluminum ash comprises the following main components: 1-30% of simple substance aluminum, 30-90% of aluminum oxide, 1-30% of aluminum nitride, 0-10% of chlorine salt, 1-10% of fluorine salt, and the total percentage content is less than or equal to 100%. The aluminum ash is mainly from a casting shop of an aluminum processing plant.

Preferably, in the step (1), the solid-to-liquid ratio of the aluminum ash to the water is 1: 0.8-50 (more preferably 1: 0.9-10).

Preferably, in the step (1), the temperature of the stirring and slurrying is 10-100 ℃ (more preferably 30-85 ℃), and the time is 10-360 min (more preferably 20-120 min).

Preferably, in step (1), the specific operation of the classification is: grading for 1-120 min (more preferably 20-90 min) at 10-100 ℃ (more preferably 20-60 ℃) to obtain fine particle slurry or fine particles with the particle size of less than or equal to 325 meshes and the content of simple substance aluminum of less than or equal to 1%. The existing treatment process of primary aluminum ash generally adopts a ball milling aluminum extraction method, because metal aluminum in the aluminum ash has good ductility, impurities are crushed in the ball milling process, aluminum particles are rolled into aluminum sheets, then the aluminum sheets are separated out through screening, the aperture of a screen is about 100 meshes generally, secondary aluminum ash below the screen is still about 5-8% of metal aluminum powder, and when the aperture of the screen is 100-200 meshes, 200-325 meshes or below 325 meshes, the secondary aluminum ash respectively contains 8-5%, 5-3% and 3-1% of metal aluminum powder. The smaller the particles, the more reactive the aluminum powder, the more easily the aluminum powder reacts with water to generate hydrogen in the wet grinding process if the aluminum powder is not treated, and the hydrogen belongs to 2.1 types of combustible gas, the ignition energy in the air is very low, 0.01MJ, and the explosion of the mixture of the hydrogen and the air can be caused by common impact and friction. The method can quickly and efficiently classify most of aluminum-containing substances by mixing and slurrying the aluminum ash and then classifying or slurrying after classification, thereby reducing the hydrogen release in the ball milling process and providing possibility for safe production.

Preferably, the coarse particle slurry with the particle size of more than 325 meshes obtained by classification is subjected to pressure filtration to obtain the aluminum-containing powder paste. The aluminum-containing powder paste contains 10-60% of aluminum, and can be used as aluminum powder for fireworks, air-added brick aluminum powder paste and the like.

Preferably, in the step (1), the classification is one or more of sedimentation classification, cyclone classification or screening classification. The screening and grading are preferably performed by using a high-frequency vibrating screen, and the vibration frequency of the high-frequency vibrating screen is 2000-6000 r/min.

Preferably, in step (2), the leaching agent is a mixture of a ferric salt and/or a cupric salt and ammonia water. The method of the invention adds the leaching agent in the wet grinding process, and can further oxidize and leach the single-mass aluminum without hydrolysis, thereby reducing the release of hydrogen in the wet grinding process.

Preferably, in the step (2), the amount of the ferric salt and/or the cupric salt is 0.8-3.0% of the dry mass of the fine particle slurry.

Preferably, in the step (2), the amount of the ammonia water is 0.3-5.0% of the dry basis weight of the fine particle slurry. The ammonia water can complex and oxidize residual copper ions and metal oxides such as copper, chromium, zinc and the like in aluminum ash.

Preferably, in the step (2), the ferric salt is one or more of ferric chloride, ferric sulfate, ferric phosphate or ferric nitrate, and hydrates thereof. The reaction equation of the trivalent ferric salt is as follows: 3Fe³⁺+Al ==3Fe²⁺+ Al³⁺。

Preferably, in the step (2), the cupric salt is one or more of copper sulfate, copper chloride, copper nitrate or copper phosphate, and hydrates thereof. The reaction equation of the cupric salt is as follows: 3Cu²⁺+Al==3Cu⁺+Al³⁺。

Preferably, in the step (2), the mass concentration of the ammonia water is 3-30%.

Preferably, in the step (2), the temperature of the leaching reaction is 10-100 ℃ (more preferably 30-60 ℃) and the time is 0.1-2.0 h (more preferably 0.2-1.5 h).

Preferably, in the step (3), the ball milling deamination is one-stage or two-stage ball milling deamination.

Preferably, the specific operation of the one-stage ball milling deamination is as follows: ball milling is carried out for 1-2 h at the temperature of less than 60 ℃ (more preferably 30-50 ℃) and the rotating speed of 20-40 r/min.

Preferably, during the two-stage ball milling deamination, the slurry after the first-stage ball milling is further classified, and the slurry with fine particles less than or equal to 325 meshes is subjected to the second-stage ball milling deamination for 1 to 20 hours (more preferably 4 to 12 hours) at the temperature of between 60 and 90 ℃ and the rotating speed of between 20 and 40r/min until the total concentration of ammonia gas and hydrogen gas in the released gas is less than 10 ppm.

By utilizing the energy generated by grinding and the crushing process, the hydrolysate on the surface of the aluminum ash can be timely dropped off, all nitrogen-containing substances can contact water as soon as possible, the hydrolysis of the aluminum nitride is accelerated, and the hydrolyzed materials can not bring new impurities.

Preferably, the temperature of the classification is 10-90 ℃ (more preferably 30-50 ℃) and the time is 1-120 min (more preferably 20-60 min).

Preferably, the classification is one or more of sedimentation classification, cyclone classification or screening classification.

Preferably, in the step (3), the equipment used for ball milling deamination is a closed system.

Preferably, in the step (3), the volume concentration of hydrogen in the tail gas treatment system and the volume concentration of ammonia in the tail gas treatment system are controlled to be less than or equal to 3% and less than or equal to 12% in a manner of introducing air or inert gas into the tail gas generated in the ball milling dehydrogenation process. The operation can ensure the safety of the production process. The inert gas is argon or nitrogen.

Preferably, the tail gas is absorbed by water or dilute sulfuric acid with the mass fraction of 1-10%.

Preferably, in the step (3), the equipment used for the ball milling deamination is one or more of a ball mill, a Raymond mill, a rod mill, a vertical mill, a colloid mill, a stirring mill, a vibration mill and the like.

Preferably, in the step (3), the salt is removed from the filtrate obtained by filtering to obtain the salt residue.

Preferably, in the step (3), the volume ratio of the deamination slurry to the washing water is 1: 0.5-3.0 (more preferably 1: 1-2).

Preferably, in the step (3), the obtained harmless aluminum ash is roasted and dehydrated for 1-3 hours at the temperature of 1000-1200 ℃ to obtain the regenerated aluminum oxide. The regenerated alumina has extremely low water content and can be directly used as a raw material of electrolytic aluminum.

The method has the following technical effects:

(1) according to the method, the slurrying pretreatment is carried out before the wet grinding of the aluminum ash, and the classification is carried out continuously, so that the content of metal aluminum in the aluminum ash is reduced to below 1-3%, and metal aluminum which cannot be separated is further subjected to oxidation leaching by using a leaching agent, the release of hydrogen in the wet grinding process is comprehensively reduced, the safety of the wet grinding process is ensured, and the method is simple, low in cost and suitable for industrial production;

(2) the method controls the concentration of hydrogen and ammonia in the closed system for ball milling dehydrogenation by means of air induction or inert gas introduction, thereby further improving the safety factor of the production process;

(3) al in the harmless aluminum ash obtained by the method of the invention₂O₃The mass content of the aluminum nitride is up to 95 percent, the mass content of the aluminum nitride is less than or equal to 0.02 percent, the mass content of the metal aluminum is less than or equal to 0.01 percent, and the mass content of the salt is less than or equal to 0.2 percent, thereby meeting the GB/T24483-2009 standard and being used as a water purifying agent, ceramics, glass, refractory materials, building materials or raw materials of electrolytic aluminum.

Detailed Description

The present invention will be further described with reference to the following examples.

The aluminum ash 1-3 used in the embodiment of the invention are all from a casting workshop of an aluminum processing factory, the aluminum ash 1 is generated for producing A356 alloy castings, and the main components are as follows: 10% of simple substance aluminum, 46% of aluminum oxide, 18% of aluminum nitride, 2% of sodium chloride, 1.6% of potassium chloride, 0.9% of sodium fluoride, and the aluminum ash 2 generated for producing a 6063 alloy bar, and the aluminum ash comprises the following main components: 12% of simple substance aluminum, 58% of aluminum oxide, 15% of aluminum nitride, 3.2% of magnesium chloride, 2.8% of potassium chloride, 0.8% of aluminum fluoride and 3% of aluminum ash, wherein the aluminum ash is produced by electrolyzing pure aluminum ingots, and the aluminum ash comprises the following main components: 13% of simple substance aluminum, 65% of aluminum oxide, 15% of aluminum nitride, 2.2% of sodium fluoride and 3.6% of aluminum fluoride; the chemical reagents used in the examples of the present invention, unless otherwise specified, are commercially available in a conventional manner.