CN110818157A - A treatment method for recycling waste acid from chemical polishing tank of aluminum profile - Google Patents

Abstract

The invention discloses a treatment method for recycling waste acid of an aluminum profile chemical polishing tank. The steps are: (1) Dilution by adding water: take the waste acid from the chemical polishing tank of aluminum profiles in a strong acid-resistant container, add pure water under stirring conditions, and stir to obtain a waste acid diluent; (2) Membrane separation: the obtained waste acid diluent is used The microporous membrane equipment performs solid-liquid separation on the waste acid diluent; (3) Heating reaction: put the membrane permeate of the waste acid diluent into the reaction kettle for heating reaction, turn on the cold water to reflux, and stir to obtain the reaction solution; (4) Seed induction : The aluminum phosphate in the reaction solution is induced to fully form aluminum phosphate precipitation by the crushed and sieved additional aluminum phosphate seed crystals; ; ⑹ concentration and composition adjustment. The method is easy to operate, the process is simple, the cost is low, there is no pollution, the aluminum ions are fully removed, the appearance is clear and transparent, the acid can be recycled, the utilization rate of raw materials is high, and it can be mechanized.

Description

A treatment method for recycling waste acid from chemical polishing tank of aluminum profile

technical field

The invention belongs to the technical field of aluminum profile processing, and more particularly relates to a processing method for recycling waste acid of chemical polishing tank for aluminum profiles. It is suitable for the recycling of waste acid of chemical polishing tank for aluminum profiles of any formula in the aluminum profile processing industry, the recycling treatment of waste acid from electrolytic polishing tanks for aluminum profiles in the aluminum profile processing industry, and the waste acid containing aluminum in the aluminum profile processing industry. The recycling process is used.

Background technique

Aluminum profile polishing, its purpose is to make the aluminum profile produce a bright surface. According to the polishing process, it can be divided into chemical polishing and electrolytic polishing. Due to the low cost and simple process of chemical polishing, chemical polishing is mainly used for aluminum profile polishing at present, while electrolytic polishing is only used for polishing aluminum profiles with special uses.

Chemical polishing was invented in the late 1940s. At that time, Henley was doing a phosphoric acid-sulfuric acid type electrolytic polishing test. When there was no electricity, he found that the corrosion of aluminum parts had a bright effect. Then he carefully studied this phenomenon and obtained the earliest chemical polishing process: The proportion of acid solution is 75% (volume fraction) of phosphoric acid and 25% (volume fraction) of sulfuric acid, and the operating temperature is 90-100 °C. Later, it was found that adding 10% nitric acid in the above process can get a particularly bright effect. At this time, chemical polishing was applied in the industry, and the corresponding patents were published one after another. Bright anodizing has steadily entered the market, replacing the nickel-chromium plating process on some steel or copper.

Chemical polishing does not require electricity or special fixtures. It is simple to operate, but requires good heating and ventilation equipment. The use of high-purity aluminum can achieve the effect of 100% reflectivity, and ordinary aluminum alloys can also achieve decorative gloss. Since chemical polishing is less expensive than electrolytic polishing, most bright anodizing is matched with chemical polishing. The most commonly used chemical polishing process is: phosphoric acid 75% (volume fraction), nitric acid 15% (volume fraction), sulfuric acid 10% (volume fraction), the operating temperature is 90 ~ 110 ° C, and the time is 0.5 ~ 3min. Some processes only have phosphoric acid and nitric acid, and some add acetic acid, chromic acid or hydrofluoric acid. Adding a small amount of diamond salt, nickel salt, and copper salt can increase the brightness of polishing. The biggest disadvantage of chemical polishing is that it will produce NOX toxic gas. The yellow NOX gas is a strong carcinogen, and it is a "yellow dragon" that is difficult to shake off in the chemical polishing workshop. People have adopted many methods to solve this technical problem. Japan's Tajima uses "clathrate" compounds to absorb toxic gases to obtain a new process for chemical polishing without yellow smoke; Germany uses 16% (volume fraction) for aluminum parts with a purity of 99.99%. ) of ammonium bifluoride, 13% (volume fraction) nitric acid, 25g/L dextrin, the operating temperature is low, and the gas evolution is very small. Kaiser Aluminum & Chemicals invented a similar process (volume fraction): 2.5% nitric acid, 0.60% ammonium bifluoride, 0.6% chromic acid, 0.6% glycerol, 0.05% copper nitrate. There are also phosphoric acid-sulfuric acid formulas that add organic sulfides instead of nitric acid to obtain a yellow-smoke-free polishing process.

In short, the chemical polishing process widely used in the aluminum profile industry at present, no matter which chemical polishing acid formula, the core and main acid components are phosphoric acid, sulfuric acid and nitric acid in order. In the chemical polishing process of aluminum profiles, the acid solution is placed in the polishing tank, and the aluminum profiles are in contact with the acid solution for a short time. Due to the corrosion of the acid solution, the aluminum profiles have a bright surface.

As the aluminum profile is corroded by the acid solution in the chemical polishing tank to produce a bright surface, the aluminum on the surface of the aluminum profile will form aluminum ions and dissolve in the acid solution. At the same time, due to the corrosion of the acid solution and the aluminum profile, the concentration of the acid solution will decrease. . When the concentration of aluminum ions in the acid solution of the chemical polishing tank rises to a certain value and the concentration of the acid solution decreases to a certain value, the polishing effect is seriously reduced. At this time, the acid solution of the chemical polishing tank needs to be replaced by a freshly prepared acid solution. Waste acid is produced. A medium-sized aluminum profile processing company produces about 6 to 15 tons of waste acid per day. Due to the different formulations and processes of the chemical polishing tank acid solution of each company, the composition of the chemical polishing tank waste acid is also different, but the basic composition of the chemical polishing tank waste acid is: phosphoric acid 40-60% (mass fraction), sulfuric acid 20% ~40% (mass fraction), moisture 8-20% (mass fraction), aluminum ions 2-6% (mass fraction) and a small amount of other metal ions.

Due to the high viscosity, high concentration, high acidity, dirty appearance and toxic metal ions of the waste acid in the chemical polishing tank for aluminum profiles, the processing cost is extremely high and the difficulty is extremely high, and a large amount of solid waste is produced, which pollutes the environment greatly. For the treatment and utilization of waste acid in chemical polishing tank of aluminum profile, there is currently no effective method. Therefore, studying the treatment technology of waste acid in chemical polishing tank for aluminum profiles has important and realistic social, economic and environmental significance for the clean production of aluminum profile industry, reducing environmental pollution and increasing economic benefits.

SUMMARY OF THE INVENTION

Aiming at the difficulty in processing the waste acid of the chemical polishing tank of aluminum profiles, serious waste pollution and the deficiencies in the prior art, the purpose of the present invention is to provide a treatment method for recycling the waste acid of the chemical polishing tank of aluminum profiles. It is easy to operate, the process is simple, the cost is low, there is no pollution, the aluminum ions are fully removed, the appearance is clear and transparent, the acid can be recycled, the utilization rate of raw materials is high, and the mechanized aluminum profile chemical polishing tank waste acid recycling treatment.

In order to achieve the above-mentioned purpose, the present invention adopts the following technical measures:

The technical idea of the present invention is as follows: utilizing the feature that the water-insoluble components in the waste acid of the chemical polishing tank of the aluminum profile can be separated by a membrane, and the property that phosphoric acid reacts with aluminum ions to generate water-insoluble aluminum phosphate, the waste acid of the chemical polishing tank of the aluminum profile is diluted by adding water. The membrane permeate diluted with waste acid obtained after separation from the membrane generates aluminum phosphate through reflux heating reaction, adding aluminum phosphate crystal seeds, and the aluminum phosphate generated by the induction reaction forms water-insoluble aluminum phosphate crystals. The waste acid diluent that removes aluminum ions is heated, concentrated and adjusted to obtain a recyclable acid solution for chemical polishing of aluminum profiles.

A processing method for recycling waste acid of aluminum profile chemical polishing tank, characterized in that, the steps of the processing method are as follows:

(1) Dilution by adding water: Take the waste acid of the chemical polishing tank for aluminum profiles in a strong acid-resistant container, and add pure water with a mass of 1.0 to 5.0 times the quality of the waste acid of the chemical polishing tank for aluminum profiles under stirring conditions. Dilute the waste acid in the chemical polishing tank of the aluminum profile, and continue stirring for 0.5 to 5 hours to obtain the waste acid dilution for use. During the whole process of controlling this step, the stirring speed is 10-300 rpm.

The waste acid of the chemical polishing tank for aluminum profiles is the acid solution that remains after the mixed acid solution used for chemical polishing of aluminum profiles is chemically polished in the polishing tank, can no longer be used, and needs to be discarded, and its main components are: Phosphoric acid 40-60% (mass fraction), sulfuric acid 20-40% (mass fraction), aluminum ions 2-6% (mass fraction) and moisture 8-20% (mass fraction); the pure water refers to the conductivity Reverse osmosis pure water, ion exchange pure water and distillation condensation pure water with a rate lower than 10-3s/m.

Preferably, the waste acid of the chemical polishing tank for aluminum profiles is the acid solution that remains after chemical polishing of the aluminum profiles in the polishing tank, which is unusable and needs to be discarded. The ingredients are: phosphoric acid 45-55% (mass fraction), sulfuric acid 25-35% (mass fraction), aluminum ions 3-5% (mass fraction) and moisture 10-15% (mass fraction); the pure water, Refers to reverse osmosis pure water with conductivity lower than 5×10 ^-4 s/m.

(2) Membrane separation: control step (1) The temperature of the obtained waste acid diluent is 5-70 °C, and the waste acid diluent is solid-liquid separated with a microporous membrane device to separate insoluble solids, and the membrane permeation of the waste acid diluent is obtained. Liquid backup.

In the microporous membrane device, the membrane material is silicon carbide, the membrane component is in the form of a honeycomb-type inner tubular membrane, and the membrane pores are 1, 0.5, 0.1 and 0.04 μm in size.

Preferably, in the microporous membrane device, the membrane material is silicon carbide, the membrane module is in the form of a honeycomb-type inner tubular membrane, and the membrane pore size is 0.1 and 0.04 μm.

(3) Heating reaction: put the membrane permeate of the waste acid diluent obtained in step (2) into a reactor or other container, turn on the reflux of cold water, and under constant stirring, heat it to the phosphoric acid dissociation reaction temperature and maintain the phosphoric acid dissociation reaction temperature, continue to heat and stir the reaction for 1.0 to 15 hours, so that phosphoric acid and aluminum ions in the reaction are reacted to generate aluminum phosphate, and the reaction solution is obtained for subsequent use. The stirring speed in this step is controlled to be 10-300 rpm.

The phosphoric acid dissociation reaction temperature is a temperature that can promote the generation of aluminum phosphate, and its range is 35-120°C.

Preferably, the phosphoric acid dissociation reaction temperature is a temperature that can promote the generation of aluminum phosphate, and its range is 60-110°C.

(4) Seed induction: take solid aluminum phosphate, crush it with a stainless steel pulverizer, and pass the pulverized material through a standard sieve to obtain aluminum phosphate seeds. Under the condition of constant stirring, add aluminum phosphate crystal seeds with a mass fraction of 0.05 to 5% of the reaction solution to the reaction solution obtained in step (3), turn off the heating and let it naturally cool down to 0 to 35 ° C, and continue to stir for 1.0 to 25 hours. The aluminum seed crystal induces the aluminum phosphate in the reaction solution to fully form aluminum phosphate precipitation to obtain a reaction solution in which aluminum phosphate is precipitated. The stirring speed in this step is controlled to be 100-400 rpm.

The solid aluminum phosphate is analytically pure or chemically pure aluminum phosphate crystal without crystal water or with crystal water; the standard sieve is sieved, and the size of the standard sieve is 40-600 mesh.

Preferably, the solid aluminum phosphate is analytically pure aluminum phosphate crystals without crystal water; the standard sieve is sieved, and the size of the standard sieve is 80-400 mesh.

⑸Membrane separation: control the temperature of the reaction solution obtained in step ⑷ to be 5-70°C, and use microporous membrane equipment to separate solid-liquid, separate insoluble aluminum phosphate precipitate, and obtain aluminum profile chemical polishing tank The dealumination waste acid diluent is ready for use.

In the microporous membrane device, the membrane material is silicon carbide, the membrane component is in the form of a honeycomb-type inner tubular membrane, and the membrane pores are 1, 0.5, 0.1 and 0.04 μm in size.

Preferably, in the microporous membrane device, the membrane material is silicon carbide, the membrane module is in the form of a honeycomb-type inner tubular membrane, and the membrane pore size is 0.1 and 0.04 μm.

(6) Concentration and composition adjustment: Concentrate the waste acid diluent of dealumination in the chemical polishing tank for aluminum profiles obtained in step (5) by the heating concentration method to a moisture content of 10-15% to obtain a dealumination acid solution in the chemical polishing tank for aluminum profiles; analysis Determine the content of phosphoric acid and sulfuric acid, and add the corresponding acid solution according to the requirements of the mass percentage of each acid solution in the aluminum profile chemical polishing tank acid solution required by the chemical polishing process to obtain a recyclable chemical polishing tank acid liquid for chemical polishing of the next batch of aluminium profiles. The temperature of the material in the whole process of this step is controlled to be 20-110°C.

The heating concentration method is a forced circulation vacuum concentration method or a rising-falling film concentration method.

Preferably, the heating concentration method is a forced circulation vacuum concentration method.

Through the technical measures of the above six steps, the most critical are step (2) membrane separation, step (3) heating reaction and step (4) seed induction, mainly through the filtration of strong corrosion-resistant silicon carbide membrane to solve the problem of high concentration and viscosity. The filtration of insoluble impurities in the dealumination waste acid of the polishing tank, the dissociation of phosphoric acid to generate aluminum phosphate and the use of aluminum phosphate seeds to induce the crystallization of aluminum phosphate solve the technical problems and difficulties such as the solid phase precipitation of aluminum phosphate by controlling the heating reaction of temperature. It mainly achieves the complete separation of insoluble impurities in the dealumination waste acid of the chemical polishing tank for aluminum profiles, the removal of aluminum ions that hinder the recycling of the waste acid in the chemical polishing tank for aluminum profiles, and the chemical polishing tank for aluminum profiles through concentration and composition adjustment. Technical effect of recycling of dealumination waste acid. Since the current dealumination waste acid of the chemical polishing tank for aluminum profiles is directly discharged as waste after neutralization with alkali, there is almost no technical solution. Therefore, the progress of the present invention compared with the prior art is reflected in innovation, resource utilization and environmental protection. aspect.

Through the technical treatment of the invention, in the waste acid of the chemical polishing tank for aluminum profiles, the removal rate of insoluble impurities is 100%, and the appearance is clear and transparent; the retention rate of sulfuric acid is 100%; the removal rate of aluminum ions is over 99.9%; the retention rate of phosphoric acid is 75% -85% (loss of phosphoric acid to aluminum phosphate). The treated aluminum profile chemical polishing tank dealumination acid solution obtained by adjusting the composition of the chemical polishing tank acid solution can completely be used for the chemical polishing of the next batch of aluminum profiles.

Compared with the prior art, the advantages and beneficial effects of the method of the present invention are:

Low cost, no pollution, sufficient removal of aluminum ions, clear and transparent appearance, recyclable acid, high utilization rate of raw materials, simple process, mechanized treatment, and suitable for large and small production scales.

Aiming at the difficulty in the treatment of waste acid in the chemical polishing tank of aluminum profiles, the serious waste pollution and the deficiencies in the prior art, the purpose of the present invention is to provide a low-cost, pollution-free, acid recyclable, and raw material utilization rate. The invention relates to a treatment method for recycling waste acid of chemical polishing tank of aluminum profile with high technology, simple process and mechanization.

The recyclable waste acid of the chemical polishing tank for aluminum profiles treated by the invention is a colorless to blue-green uniform liquid, which fully removes aluminum ions and turbidity that affect the chemical polishing effect, and retains phosphoric acid, sulfuric acid and other acids. The use effect is the same as that of the freshly prepared chemical polishing acid solution, which avoids the strong environmental pollution of waste acid, high treatment costs and waste of useful resources.

Description of drawings

FIG. 1 is a process flow diagram of a treatment method for recycling waste acid of an aluminum profile chemical polishing tank.

Detailed ways

The applicant will further describe the method of the present invention in detail with reference to specific embodiments below.

Example 1:

A processing method for recycling waste acid of aluminum profile chemical polishing tank, the steps of which are:

(1) Dilution with water: take the main composition of phosphoric acid 50% (mass fraction), sulfuric acid 30% (mass fraction), moisture 13% (mass fraction), aluminum ions 4% (mass fraction) and insoluble impurities 3% (mass fraction) Put 1000 grams of waste acid in the chemical polishing tank of aluminum profile into a beaker, add 1000 grams of reverse osmosis pure water under the stirring condition of the stirring speed of 100rpm, dilute the waste acid with high concentration, high viscosity and cloudy appearance, and continue stirring for 1.5 hours. The waste acid diluent is available for use. The composition of waste acid diluent is phosphoric acid 25% (mass fraction), sulfuric acid 15% (mass fraction), moisture 56.5% (mass fraction), aluminum ion 2% (mass fraction) and insoluble impurities 1.5% (mass fraction).

(2) Membrane separation: control step (1) The temperature of the obtained waste acid diluent is 25°C, and the waste acid is diluted by a microporous membrane device with a membrane material of silicon carbide, a membrane hole of 0.04 μm and a membrane module form of a honeycomb-type inner tubular membrane. The liquid is separated from solid and liquid, and the insoluble solids are separated to obtain 1,950 g of the membrane permeated liquid of the waste acid diluent for use.

(3) Heating reaction: put the membrane permeate of the waste acid diluent obtained in step (2) into the heating reactor, turn on the cold water reflux, and under the stirring condition of the stirring speed of 80 rpm, heat it to 95 ° C and maintain 95 ° C, continue The reaction is heated and stirred for 8 hours, and the phosphoric acid therein is reacted with aluminum ions to generate aluminum phosphate, and the reaction solution is obtained for subsequent use.

(4) Seed induction: take analytically pure non-crystalline aluminum phosphate, grind it with a stainless steel pulverizer, and sieve the pulverized material through a 200-mesh standard sieve to obtain aluminum phosphate seed crystals. Under the stirring condition of a stirring speed of 150 rpm, to the reaction solution obtained in step (3), add aluminum phosphate crystal seeds with a mass fraction of 0.5% of the reaction solution, turn off the heating, let it naturally cool down to 10 ° C, and continue stirring for 10 hours to make aluminum phosphate crystal seeds. The aluminum phosphate in the reaction solution is induced to fully form an aluminum phosphate precipitate to obtain a reaction solution in which the aluminum phosphate is precipitated.

(5) Membrane separation: control the temperature of the reaction solution obtained in step (4) precipitation of aluminum phosphate to be 10 °C, and use a microporous membrane device with a membrane material of silicon carbide, a membrane hole of 0.04 μm, and a membrane module form of a honeycomb-type inner tubular membrane. It carries out solid-liquid separation to separate out insoluble aluminum phosphate precipitates, and obtains 1770 grams of the aluminum profile chemical polishing tank dealumination waste acid diluent for use.

(6) Concentration and composition adjustment: Concentrate the waste acid diluent of dealumination in the chemical polishing tank of the aluminum profile obtained in step (5) to the moisture mass percentage of 13%, to obtain the aluminum profile chemical polishing tank dealumination acid solution with the main composition of phosphoric acid 36.0% (mass fraction), sulfuric acid 50.99% (mass fraction), moisture 13% (mass fraction) and aluminum ions 0.01% (mass fraction); According to the calculation, add 85% phosphoric acid and 98% sulfuric acid, so that the relative content of phosphoric acid is 73% (mass fraction) and the sulfuric acid content is 27% (mass fraction), that is, a recyclable chemical polishing tank acid solution is obtained. Chemical polishing for the next batch of aluminum profiles.

It was determined that after the waste acid of aluminum profile chemical polishing tank was treated by the above method, the retention rate of phosphoric acid was 72% (28% phosphoric acid produced aluminum phosphate), the retention rate of sulfuric acid was 100%, and the removal rate of aluminum ions was 99.9%. The impurity removal rate is 100%, and the appearance is clear and transparent. The chemical polishing tank acid solution obtained by adjusting the composition of the dealumination acid solution in the chemical polishing tank for aluminum profiles can be used for the chemical polishing of the next batch of aluminum profiles.

Example 2:

A processing method for recycling waste acid of aluminum profile chemical polishing tank, the steps of which are:

(1) Dilution with water: take the main components as phosphoric acid 65% (mass fraction), sulfuric acid 15% (mass fraction), moisture 15% (mass fraction), aluminum ions 4.5% (mass fraction), copper ions 0.2% (mass fraction) and Insoluble impurities 0.3% (mass fraction) of aluminum profile chemical polishing tank waste acid 2.5 kg in a beaker, under the stirring condition of the stirring speed of 100rpm, add reverse osmosis pure water 2.5 kg, for high concentration, high viscosity and turbid appearance of waste The acid was diluted, and the stirring was continued for 2 hours to obtain a waste acid dilution for use. The composition of waste acid diluent is phosphoric acid 32.5% (mass fraction), sulfuric acid 7.5% (mass fraction), moisture 57.5% (mass fraction), aluminum ion 2.25% (mass fraction), copper ion 0.1% (mass fraction) and insoluble impurities 0.15% (mass fraction).

(2) Membrane separation: control step (1) The temperature of the obtained waste acid diluent is 5 °C, and the waste acid is diluted by a microporous membrane device with a membrane material of silicon carbide, a membrane hole of 0.1 μm and a membrane module form of a honeycomb-type inner tubular membrane. The liquid is separated from solid and liquid, and the insoluble solids are separated to obtain 4.95 kg of the membrane permeate of the waste acid diluent for use.

(3) Heating reaction: put the membrane permeate of the waste acid dilution obtained in step (2) into the heating reaction kettle, turn on the cold water reflux, and under the stirring condition of the stirring speed of 70 rpm, heat it to 90 ° C and maintain 90 ° C, continue The reaction is heated and stirred for 10 hours, and the phosphoric acid therein is reacted with aluminum ions to generate aluminum phosphate, and the reaction solution is obtained for subsequent use.

(4) Seed induction: take analytically pure non-crystalline aluminum phosphate, grind it with a stainless steel pulverizer, and sieve the pulverized material through a 300-mesh standard sieve to obtain aluminum phosphate seed crystals. Under the stirring condition of a stirring speed of 150 rpm, add aluminum phosphate seed crystals with a mass fraction of 0.3% of the reaction solution to the reaction solution obtained in step (3), turn off the heating, let it naturally cool down to 5 ° C, and continue stirring for 15 hours to make aluminum phosphate seed crystals. The aluminum phosphate in the reaction solution is induced to fully form an aluminum phosphate precipitate to obtain a reaction solution in which the aluminum phosphate is precipitated.

⑸ Membrane separation: control the temperature of the reaction solution obtained in step ⑷ to precipitate out aluminum phosphate to be 5°C, and use a microporous membrane device with a membrane material of silicon carbide, a membrane hole of 0.1 μm and a membrane module form of a honeycomb-type inner tubular membrane. The solid-liquid separation was carried out to separate out insoluble aluminum phosphate precipitates, and 4.81 kg of the waste acid diluent of dealumination in the chemical polishing tank for aluminum profiles was obtained for use.

(6) Concentration and composition adjustment: Concentrate the diluted solution of dealumination waste acid in the chemical polishing tank of the aluminum profile obtained in step (5) to a moisture mass percentage of 15%, the main composition is phosphoric acid 48.75% (mass fraction), sulfuric acid 36.04% (mass fraction), moisture 15% (mass fraction), aluminum ions 0.01% (mass fraction) and copper ions 0.2% (mass fraction) aluminum Profile chemical polishing tank dealumination acid solution; add 85% phosphoric acid, 98% sulfuric acid and 66% nitric acid according to the calculation, so that the relative content of phosphoric acid is 65% (mass fraction) and the relative content of nitric acid is 14% (mass fraction) ) and the relative content of sulfuric acid is 11% (mass fraction), that is, a recyclable chemical polishing tank acid solution is obtained, which is used for the chemical polishing of the next batch of aluminum profiles.

It has been determined that the phosphoric acid retention rate is 75% (25% phosphoric acid produces aluminum phosphate), the sulfuric acid retention rate is 100%, the aluminum ion removal rate is 99.9%, and the aluminum ion removal rate is 99.9%. The impurity removal rate is 100%, and the appearance is clear and transparent. The chemical polishing tank acid solution obtained by adjusting the composition of the dealumination acid solution in the chemical polishing tank for aluminum profiles can be used for the chemical polishing of the next batch of aluminum profiles.

Example 3:

A processing method for recycling waste acid of aluminum profile chemical polishing tank, the steps of which are:

(1) Dilution with water: take the main composition of phosphoric acid 55% (mass fraction), sulfuric acid 25% (mass fraction), moisture 14.5% (mass fraction), aluminum ions 5% (mass fraction) and insoluble impurities 0.5% (mass fraction) 6,000 kg of waste acid in the chemical polishing tank for aluminum profiles was placed in the reaction kettle. Under the stirring condition of the stirring speed of 100 rpm, 6,000 kg of reverse osmosis pure water was added to dilute the waste acid with high concentration, high viscosity and turbid appearance, and continue to stir for 2.5 hours, get the waste acid diluent for use. The composition of the waste acid diluent is phosphoric acid 27.5% (mass fraction), sulfuric acid 12.5% (mass fraction), moisture 57.25% (mass fraction), aluminum ions 2.5% (mass fraction) and insoluble impurities 0.25% (mass fraction).

(2) Membrane separation: control step (1) The temperature of the obtained waste acid diluent is 5 °C, and the waste acid is diluted by a microporous membrane device with a membrane material of silicon carbide, a membrane hole of 0.04 μm and a membrane module form of a honeycomb-type inner tubular membrane. The liquid is separated from solid and liquid, and the insoluble solids are separated to obtain 11,950 kg of the membrane permeate of the waste acid diluent for use.

(3) Heating reaction: put the membrane permeate of the waste acid diluent obtained in step (2) into the heating reaction kettle, turn on the cold water reflux, and under the stirring condition of the stirring speed of 100 rpm, heat it to 100 ° C and maintain 100 ° C, continue The reaction is heated and stirred for 9 hours, and the phosphoric acid therein is reacted with aluminum ions to generate aluminum phosphate, and the reaction solution is obtained for subsequent use.

(4) Seed induction: take analytically pure non-crystalline aluminum phosphate, grind it with a stainless steel pulverizer, and pass the pulverized material through a 400-mesh standard sieve to obtain aluminum phosphate seed crystals. Under the stirring condition of a stirring speed of 150 rpm, add aluminum phosphate crystal seeds with a mass fraction of 0.2% of the reaction solution to the reaction solution obtained in step (3), turn off the heating, let it naturally cool down to 5 ° C, and continue stirring for 15 hours to make aluminum phosphate crystal seeds. The aluminum phosphate in the reaction solution is induced to fully form an aluminum phosphate precipitate to obtain a reaction solution in which the aluminum phosphate is precipitated.

⑸ Membrane separation: control the temperature of the reaction solution obtained in step ⑷ to precipitate out aluminum phosphate to be 5 °C, and use a microporous membrane device with a membrane material of silicon carbide, a membrane hole of 0.04 μm and a membrane module form of a honeycomb-type inner tubular membrane. It is subjected to solid-liquid separation to separate out insoluble aluminum phosphate precipitates, to obtain 11,410 kg of waste acid diluent from dealumination in chemical polishing tank for aluminum profiles for use.

(6) Concentration and composition adjustment: Concentrate the waste acid diluent from the chemical polishing tank of the aluminum profile obtained in step (5) to the mass percentage of moisture by the forced circulation vacuum heating and concentration method at a temperature of 85 ° C and a vacuum degree of 0.097 MPa. It is 14.5%, and the main composition is phosphoric acid 37.4% (mass fraction), sulfuric acid 48.09% (mass fraction), moisture 14.5% (mass fraction) and aluminum ions 0.01% (mass fraction) dealumination acid solution for chemical polishing tank of aluminum profile ;Add 85% phosphoric acid and 98% sulfuric acid according to the calculation, so that the relative content of phosphoric acid is 72% (mass fraction) and the relative content of sulfuric acid is 27% (mass fraction), that is, a recyclable chemical polishing tank acid solution is obtained , for chemical polishing of the next batch of aluminium profiles.

It has been determined that the phosphoric acid retention rate is 68% (32% phosphoric acid produces aluminum phosphate), the sulfuric acid retention rate is 100%, the aluminum ion removal rate is 99.9%, and the aluminum ion removal rate is 99.9%. The impurity removal rate is 100%, and the appearance is clear and transparent. The chemical polishing tank acid solution obtained by adjusting the composition of the dealumination acid solution in the chemical polishing tank for aluminum profiles can be used for the chemical polishing of the next batch of aluminum profiles.

Example 4:

A processing method for recycling waste acid of aluminum profile chemical polishing tank, the steps of which are:

(1) Dilution with water: take the main components as phosphoric acid 65% (mass fraction), sulfuric acid 15% (mass fraction), moisture 15% (mass fraction), aluminum ions 3.5% (mass fraction), copper ions 0.2% (mass fraction) and Insoluble impurities 1.3% (mass fraction) of aluminum profile chemical polishing tank waste acid 5.35 kg was placed in a glass container, and under the stirring condition of the stirring speed of 90 rpm, 7 kg of reverse osmosis pure water was added. The waste acid is diluted, and stirring is continued for 2 hours to obtain a waste acid dilution for subsequent use. The composition of the waste acid diluent is phosphoric acid 28.2% (mass fraction), sulfuric acid 6.5% (mass fraction), moisture 63.2% (mass fraction), aluminum ion 1.51% (mass fraction), copper ion 0.09% (mass fraction) and insoluble Impurity 0.59% (mass fraction).

(2) Membrane separation: control step (1) The temperature of the obtained waste acid diluent is 10 °C, and the waste acid is diluted by a microporous membrane device with a membrane material of silicon carbide, a membrane hole of 0.04 μm and a membrane module form of a honeycomb-type inner tubular membrane. The liquid was subjected to solid-liquid separation to separate out insoluble solids to obtain 12.2 kg of the membrane permeate of the waste acid diluent for use.

(3) Heating reaction: put the membrane permeate of the waste acid dilution obtained in step (2) into the heating reaction kettle, turn on the cold water reflux, and under the stirring condition of the stirring speed of 75 rpm, heat it to 85 ° C and maintain 85 ° C, continue The reaction is heated and stirred for 16 hours, and the phosphoric acid therein is reacted with aluminum ions to generate aluminum phosphate, and the reaction solution is obtained for subsequent use.

(4) Seed induction: Take analytically pure non-crystalline aluminum phosphate, grind it with a stainless steel pulverizer, and sieve the pulverized material through a 120-mesh standard sieve to obtain aluminum phosphate seed crystals. Under the stirring condition of a stirring speed of 140 rpm, add aluminum phosphate crystal seeds with a mass fraction of 0.2% of the reaction solution to the reaction solution obtained in step (3), turn off the heating, let it naturally cool down to 10 ° C, and continue stirring for 16 hours. The aluminum phosphate in the reaction solution is induced to fully form an aluminum phosphate precipitate to obtain a reaction solution in which the aluminum phosphate is precipitated.

⑸Membrane separation: control the temperature of the reaction solution obtained in step ⑷ to be 10°C, and use a microporous membrane device with a membrane material of silicon carbide, a membrane pore of 0.04 μm, and a honeycomb coal-type inner tubular membrane in the form of the membrane module. It was subjected to solid-liquid separation to separate out the insoluble aluminum phosphate precipitate, and 11.4 kg of the waste acid diluent of dealumination in the chemical polishing tank for aluminum profiles was obtained for use.

(6) Concentration and composition adjustment: Concentrate the waste acid diluent of dealumination in the chemical polishing tank of the aluminum profile obtained in step (5) to the moisture mass percentage of 14%, the main composition is phosphoric acid 52.65% (mass fraction), sulfuric acid 33.12% (mass fraction), moisture 14% (mass fraction), aluminum ions 0.01% (mass fraction) and copper ions 0.22% (mass fraction) aluminum Profile chemical polishing tank dealumination acid solution; add 85% phosphoric acid, 98% sulfuric acid and 66% nitric acid according to the calculation, so that the relative content of phosphoric acid is 65% (mass fraction) and the relative content of nitric acid is 14% (mass fraction) ) and the relative content of sulfuric acid is 11% (mass fraction), that is, a recyclable chemical polishing tank acid solution is obtained, which is used for the chemical polishing of the next batch of aluminum profiles.

It was determined that after the waste acid of aluminum profile chemical polishing tank was treated by the above method, the retention rate of phosphoric acid was 81% (19% phosphoric acid produced aluminum phosphate), the retention rate of sulfuric acid was 100%, and the removal rate of aluminum ions was 99.9%. The impurity removal rate is 100%, and the appearance is clear and transparent. The chemical polishing tank acid solution obtained by adjusting the composition of the dealumination acid solution in the chemical polishing tank for aluminum profiles can be used for the chemical polishing of the next batch of aluminum profiles.

Example 5:

A processing method for recycling waste acid of aluminum profile chemical polishing tank, the steps of which are:

(1) Dilution with water: take the main composition of phosphoric acid 51% (mass fraction), sulfuric acid 29% (mass fraction), moisture 13% (mass fraction), aluminum ions 3% (mass fraction) and insoluble impurities 4% (mass fraction) 7.23 kg of waste acid from chemical polishing tank for aluminum profiles was placed in a glass container. Under the stirring condition of 120 rpm, 7.23 kg of reverse osmosis pure water was added to dilute the waste acid with high concentration, high viscosity and turbid appearance, and continued stirring for 1.5 hours. , the waste acid diluent is available for use. The composition of the waste acid diluent is phosphoric acid 25.5% (mass fraction), sulfuric acid 14.5% (mass fraction), moisture 56.5% (mass fraction), aluminum ions 1.5% (mass fraction) and insoluble impurities 2% (mass fraction).

(2) Membrane separation: control step (1) The temperature of the obtained waste acid diluent is 15°C, and the waste acid is diluted by a microporous membrane equipment whose membrane material is silicon carbide, whose membrane pores are 0.1 μm and whose membrane module is a honeycomb type inner tubular membrane. The liquid was subjected to solid-liquid separation to separate out insoluble solids to obtain 14.4 kg of the membrane permeate of the waste acid diluent for use.

(3) Heating reaction: put the membrane permeate of the waste acid dilution obtained in step (2) into the heating reaction kettle, turn on the cold water reflux, and under the stirring condition of the stirring speed of 95 rpm, heat it to 90 ° C and maintain 90 ° C, continue The reaction was heated and stirred for 12 hours, so that phosphoric acid and aluminum ions were reacted to generate aluminum phosphate, and the reaction solution was obtained for subsequent use.

(4) Seed induction: take analytically pure non-crystalline aluminum phosphate, grind it with a stainless steel pulverizer, and sieve the pulverized material through a 100-mesh standard sieve to obtain aluminum phosphate seed crystals. Under the stirring condition of a stirring speed of 150 rpm, add aluminum phosphate crystal seeds with a mass fraction of 0.35% of the reaction solution to the reaction solution obtained in step (3), turn off the heating, let it naturally cool down to 15 ° C, and continue stirring for 16 hours to make aluminum phosphate crystal seeds. The aluminum phosphate in the reaction solution is induced to fully form an aluminum phosphate precipitate to obtain a reaction solution in which the aluminum phosphate is precipitated.

⑸Membrane separation: control the temperature of the reaction solution obtained in step ⑷ to be 15°C, and the membrane material is silicon carbide, the membrane hole is 0.1μm, and the membrane module is a honeycomb-type inner tubular membrane. Microporous membrane equipment It was subjected to solid-liquid separation to separate out the insoluble aluminum phosphate precipitate, and 13.7 kg of the aluminum profile chemical polishing tank dealumination waste acid diluent was obtained for use.

(6) Concentration and composition adjustment: Concentrate the waste acid diluent of dealumination in the chemical polishing tank of the aluminum profile obtained in step (5) to the moisture mass percentage of 13%, to obtain the aluminum profile chemical polishing tank dealumination acid solution with the main composition of phosphoric acid 41.82% (mass fraction), sulfuric acid 45.17% (mass fraction), moisture 13% (mass fraction) and aluminum ions 0.01% (mass fraction); According to the calculation, add 85% phosphoric acid and 98% sulfuric acid, so that the relative content of phosphoric acid is 73% (mass fraction) and the sulfuric acid content is 27% (mass fraction), that is, a recyclable chemical polishing tank acid solution is obtained. Chemical polishing for the next batch of aluminum profiles.

It has been determined that after the waste acid of the chemical polishing tank of aluminum profile is treated by the above method, the retention rate of phosphoric acid is 82% (19% phosphoric acid produces aluminum phosphate), the retention rate of sulfuric acid is 100%, and the removal rate of aluminum ions is 99.9%. The impurity removal rate is 100%, and the appearance is clear and transparent. The chemical polishing tank acid solution obtained by adjusting the composition of the dealumination acid solution in the chemical polishing tank for aluminum profiles can be used for the chemical polishing of the next batch of aluminum profiles.

Example 6:

A processing method for recycling waste acid of aluminum profile chemical polishing tank, the steps of which are:

(1) Dilution with water: take the main components as phosphoric acid 64% (mass fraction), sulfuric acid 16% (mass fraction), moisture 15% (mass fraction), aluminum ions 3.8% (mass fraction), copper ions 0.3% (mass fraction) and Insoluble impurities 0.9% (mass fraction) of aluminum profile chemical polishing tank waste acid 1.56 kg was placed in a beaker, and under the stirring condition of a stirring speed of 95 rpm, 1.56 g of reverse osmosis pure water was added. The acid was diluted, and the stirring was continued for 1 hour to obtain a waste acid dilution for use. The composition of waste acid diluent is phosphoric acid 32% (mass fraction), sulfuric acid 8% (mass fraction), moisture 57.5% (mass fraction), aluminum ion 1.9% (mass fraction), copper ion 0.15% (mass fraction) and insoluble Impurity 0.45% (mass fraction).

(2) Membrane separation: control step (1) The temperature of the obtained waste acid diluent is 20 °C, and the waste acid is diluted by a microporous membrane device with a membrane material of silicon carbide, a membrane hole of 0.04 μm and a membrane module form of a honeycomb-type inner tubular membrane. The liquid is separated from solid and liquid, and the insoluble solids are separated to obtain 3.06 kg of the membrane permeate of the waste acid diluent for use.

(3) Heating reaction: put the membrane permeate of the waste acid diluent obtained in step (2) into the heating reactor, turn on the cold water reflux, and under the stirring condition of the stirring speed of 95 rpm, heat it to 95 ° C and maintain 95 ° C, continue The reaction was heated and stirred for 13 hours, so that phosphoric acid and aluminum ions were reacted to generate aluminum phosphate, and the reaction solution was obtained for subsequent use.

(4) Seed induction: take analytically pure non-crystalline aluminum phosphate, grind it with a stainless steel pulverizer, and sieve the pulverized material through a 200-mesh standard sieve to obtain aluminum phosphate seed crystals. Under the stirring condition of a stirring speed of 200 rpm, add aluminum phosphate crystal seeds with a mass fraction of 0.25% of the reaction solution to the reaction solution obtained in step (3), turn off the heating, let it naturally cool down to 20 ° C, and continue stirring for 13 hours to make aluminum phosphate crystal seeds. The aluminum phosphate in the reaction solution is induced to fully form an aluminum phosphate precipitate to obtain a reaction solution in which the aluminum phosphate is precipitated.

⑸Membrane separation: control the temperature of the reaction solution obtained in step ⑷ to be 20°C, the membrane material is silicon carbide, the membrane hole is 0.01μm, and the membrane module is a honeycomb coal-type inner tubular membrane. Microporous membrane equipment It was subjected to solid-liquid separation to separate out the insoluble aluminum phosphate precipitate, and 2.9 kg of the waste acid diluent of dealumination in the chemical polishing tank for aluminum profiles was obtained for use.

(6) Concentration and composition adjustment: Concentrate the diluted solution of dealumination waste acid in the chemical polishing tank of the aluminum profile obtained in step (5) to the moisture mass percentage of 15%, to obtain aluminum whose main composition is phosphoric acid 50.56% (mass fraction), sulfuric acid 34.43% (mass fraction), moisture 15% (mass fraction), aluminum ions 0.01% (mass fraction) and copper ions 0.35% (mass fraction) Profile chemical polishing tank dealumination acid solution; add 85% phosphoric acid, 98% sulfuric acid and 66% nitric acid according to the calculation, so that the relative content of phosphoric acid is 65% (mass fraction) and the relative content of nitric acid is 14% (mass fraction) ) and the relative content of sulfuric acid is 11% (mass fraction), that is, a recyclable chemical polishing tank acid solution is obtained, which is used for the chemical polishing of the next batch of aluminum profiles.

It was determined that after the waste acid of aluminum profile chemical polishing tank was treated by the above method, the retention rate of phosphoric acid was 79% (21% phosphoric acid produced aluminum phosphate), the retention rate of sulfuric acid was 100%, and the removal rate of aluminum ions was 99.9%. The impurity removal rate is 100%, and the appearance is clear and transparent. The chemical polishing tank acid solution obtained by adjusting the composition of the dealumination acid solution in the chemical polishing tank for aluminum profiles can be used for the chemical polishing of the next batch of aluminum profiles.

Example 7:

A processing method for recycling waste acid of aluminum profile chemical polishing tank, the steps of which are:

(1) Dilution with water: take the main composition of phosphoric acid 53% (mass fraction), sulfuric acid 27% (mass fraction), moisture 13% (mass fraction), aluminum ions 2.8% (mass fraction) and insoluble impurities 4.2% (mass fraction) 9.6 kg of waste acid from chemical polishing tank of aluminum profile was placed in a glass container. Under the stirring condition of stirring speed of 95 rpm, 9.6 kg of reverse osmosis pure water was added to dilute the waste acid with high concentration, high viscosity and turbid appearance, and continued stirring for 1 hour. , the waste acid diluent is available for use. The composition of the waste acid diluent is phosphoric acid 26.5% (mass fraction), sulfuric acid 13.5% (mass fraction), moisture 56.5% (mass fraction), aluminum ions 1.4% (mass fraction) and insoluble impurities 2.1% (mass fraction).

(2) Membrane separation: control step (1) The temperature of the obtained waste acid diluent is 10 °C, and the waste acid is diluted by a microporous membrane device with a membrane material of silicon carbide, a membrane hole of 0.04 μm and a membrane module form of a honeycomb-type inner tubular membrane. The liquid was subjected to solid-liquid separation to separate out insoluble solids to obtain 19.15 kg of the membrane permeate of the waste acid diluent for use.

(3) Heating reaction: put the membrane permeate of the waste acid dilution obtained in step (2) into the heating reaction kettle, turn on the cold water reflux, and under the stirring condition of the stirring speed of 95 rpm, heat it to 90 ° C and maintain 90 ° C, continue The reaction was heated and stirred for 14 hours, so that phosphoric acid and aluminum ions were reacted to generate aluminum phosphate, and the reaction solution was obtained for subsequent use.

(4) Seed induction: take analytically pure non-crystalline aluminum phosphate, grind it with a stainless steel pulverizer, and pass the pulverized material through a 160-mesh standard sieve to obtain aluminum phosphate seed crystals. Under the stirring condition of a stirring speed of 190 rpm, add aluminum phosphate crystal seeds with a mass fraction of 0.7% of the reaction solution to the reaction solution obtained in step (3), turn off the heating and let it naturally cool down to 10 ° C, and continue to stir for 18 hours to make aluminum phosphate crystal seeds. The aluminum phosphate in the reaction solution is induced to fully form an aluminum phosphate precipitate to obtain a reaction solution in which the aluminum phosphate is precipitated.

⑸Membrane separation: control the temperature of the reaction solution obtained in step ⑷ to be 10°C, and use a microporous membrane device with a membrane material of silicon carbide, a membrane pore of 0.04 μm, and a honeycomb coal-type inner tubular membrane in the form of the membrane module. It was subjected to solid-liquid separation to separate out the insoluble aluminum phosphate precipitate, and 18.5 kg of the aluminum profile chemical polishing tank dealumination waste acid diluent was obtained for use.

(6) Concentration and composition adjustment: Concentrate the diluted solution of dealumination waste acid in the chemical polishing tank of the aluminum profile obtained in step (5) to a moisture mass percentage of 13%, to obtain the aluminum profile chemical polishing tank dealumination acid solution with the main composition of phosphoric acid 42.93% (mass fraction), sulfuric acid 44.06% (mass fraction), moisture 13% (mass fraction) and aluminum ions 0.01% (mass fraction); According to the calculation, add 85% phosphoric acid and 98% sulfuric acid, so that the relative content of phosphoric acid is 73% (mass fraction) and the sulfuric acid content is 27% (mass fraction), that is, a recyclable chemical polishing tank acid solution is obtained. Chemical polishing for the next batch of aluminum profiles.

It was determined that after the waste acid of aluminum profile chemical polishing tank was treated by the above method, the retention rate of phosphoric acid was 81% (19% phosphoric acid produced aluminum phosphate), the retention rate of sulfuric acid was 100%, and the removal rate of aluminum ions was 99.9%. The impurity removal rate is 100%, and the appearance is clear and transparent. The chemical polishing tank acid solution obtained by adjusting the composition of the dealumination acid solution in the chemical polishing tank for aluminum profiles can be used for the chemical polishing of the next batch of aluminum profiles.

Example 8:

A processing method for recycling waste acid of aluminum profile chemical polishing tank, the steps of which are:

(1) Dilution with water: take the main components as phosphoric acid 63% (mass fraction), sulfuric acid 17% (mass fraction), moisture 15% (mass fraction), aluminum ions 4.2% (mass fraction), copper ions 0.28% (mass fraction) and Insoluble impurities 0.52% (mass fraction) aluminum profile chemical polishing tank waste acid 3.75 kg was placed in a glass container, under the stirring condition of the stirring speed of 95 rpm, adding reverse osmosis pure water 3.75 grams, for high concentration, high viscosity and turbid appearance. The waste acid was diluted, and the stirring was continued for 1.5 hours to obtain a waste acid diluent for subsequent use. The composition of waste acid diluent is phosphoric acid 31.5% (mass fraction), sulfuric acid 8.5% (mass fraction), moisture 57.5% (mass fraction), aluminum ion 2.1% (mass fraction), copper ion 0.14% (mass fraction) and insoluble Impurity 0.52% (mass fraction).

(2) Membrane separation: control step (1) The temperature of the obtained waste acid diluent is 30°C, and the waste acid is diluted by a microporous membrane equipment whose membrane material is silicon carbide, whose membrane pores are 0.1 μm and whose membrane module is a honeycomb type inner tubular membrane. The liquid was subjected to solid-liquid separation to separate out insoluble solids to obtain 7.49 kg of the membrane permeate of the waste acid diluent for use.

(3) Heating reaction: put the membrane permeate of the waste acid diluent obtained in step (2) into the heating reactor, turn on the cold water reflux, and under the stirring condition of the stirring speed of 70 rpm, heat it to 100 ° C and maintain 100 ° C, continue The reaction is heated and stirred for 9 hours, and the phosphoric acid therein is reacted with aluminum ions to generate aluminum phosphate, and the reaction solution is obtained for subsequent use.

(4) Seed induction: take analytically pure non-crystalline aluminum phosphate, grind it with a stainless steel pulverizer, and sieve the pulverized material through a 140-mesh standard sieve to obtain aluminum phosphate seed crystals. Under the stirring condition of a stirring speed of 150 rpm, add aluminum phosphate crystal seeds with a mass fraction of 0.3% of the reaction solution to the reaction solution obtained in step (3), turn off the heating, let it naturally cool down to 5 ° C, and continue stirring for 15 hours. The aluminum phosphate in the induction reaction solution is sufficiently formed to form an aluminum phosphate precipitate to obtain a reaction solution in which the aluminum phosphate is precipitated.

⑸ Membrane separation: control the temperature of the reaction solution obtained in step ⑷ to be 5 ℃, use the membrane material as silicon carbide, the membrane hole is 0.1 μm and the membrane module form is the honeycomb type inner tubular membrane microporous membrane equipment It is subjected to solid-liquid separation to separate out the insoluble aluminum phosphate precipitate, and 4700 grams of the waste acid diluent for dealumination of aluminum profile chemical polishing tank is obtained for use.

(6) Concentration and composition adjustment: Concentrate the diluted solution of dealumination waste acid in the chemical polishing tank of the aluminum profile obtained in step (5) to a moisture mass percentage of 15%, the main composition is phosphoric acid 48.51% (mass fraction), sulfuric acid 36.28% (mass fraction), moisture 15% (mass fraction), aluminum ions 0.01% (mass fraction) and copper ions 0.2% (mass fraction) aluminum Profile chemical polishing tank dealumination acid solution; add 85% phosphoric acid, 98% sulfuric acid and 66% nitric acid according to the calculation, so that the relative content of phosphoric acid is 65% (mass fraction) and the relative content of nitric acid is 14% (mass fraction) ) and the relative content of sulfuric acid is 11% (mass fraction), that is, a recyclable chemical polishing tank acid solution is obtained, which is used for the chemical polishing of the next batch of aluminum profiles.

It has been determined that the phosphoric acid retention rate is 77% (23% phosphoric acid produces aluminum phosphate), the sulfuric acid retention rate is 100%, the aluminum ion removal rate is 99.9%, and the aluminum ion removal rate is 99.9%. The impurity removal rate is 100%, and the appearance is clear and transparent. The chemical polishing tank acid solution obtained by adjusting the composition of the dealumination acid solution in the chemical polishing tank for aluminum profiles can be used for the chemical polishing of the next batch of aluminum profiles.

Example 9:

A processing method for recycling waste acid of aluminum profile chemical polishing tank, the steps of which are:

(1) Dilution with water: take the main composition of phosphoric acid 55% (mass fraction), sulfuric acid 25% (mass fraction), moisture 13% (mass fraction), aluminum ions 3.4% (mass fraction) and insoluble impurities 3.6% (mass fraction) 55.6 kg of waste acid from chemical polishing tank of aluminum profile was placed in a glass container. Under the stirring condition of stirring speed of 115 rpm, 55.6 kg of reverse osmosis pure water was added to dilute the waste acid with high concentration, high viscosity and turbid appearance, and continued stirring for 3 hours. , the waste acid diluent is available for use. The composition of the waste acid diluent is phosphoric acid 27.5% (mass fraction), sulfuric acid 12.5% (mass fraction), moisture 56.5% (mass fraction), aluminum ions 1.7% (mass fraction) and insoluble impurities 1.8% (mass fraction).

(2) Membrane separation: control step (1) The temperature of the obtained waste acid diluent is 30 °C, and the waste acid is diluted by a microporous membrane device with a membrane material of silicon carbide, a membrane hole of 0.04 μm and a membrane module form of a honeycomb-type inner tubular membrane. The liquid was subjected to solid-liquid separation to separate out insoluble solids to obtain 11.1 kg of the membrane permeate of the waste acid diluent for use.

(3) Heating reaction: put the membrane permeate of the waste acid diluent obtained in step (2) into the heating reaction kettle, turn on the cold water reflux, and under the stirring condition of the stirring speed of 100 rpm, heat it to 105 ° C and maintain 105 ° C, continue The reaction is heated and stirred for 9 hours, and the phosphoric acid therein is reacted with aluminum ions to generate aluminum phosphate, and the reaction solution is obtained for subsequent use.

(4) Seed induction: take analytically pure non-crystalline aluminum phosphate, grind it with a stainless steel pulverizer, and sieve the pulverized material through a 300-mesh standard sieve to obtain aluminum phosphate seed crystals. Under the stirring condition of a stirring speed of 250 rpm, add aluminum phosphate crystal seeds with a mass fraction of 0.19% of the reaction solution to the reaction solution obtained in step (3), turn off the heating, let it naturally cool down to 30 ° C, and continue stirring for 20 hours. The aluminum phosphate in the reaction solution is induced to fully form an aluminum phosphate precipitate to obtain a reaction solution in which the aluminum phosphate is precipitated.

⑸ Membrane separation: control the temperature of the reaction solution obtained in step ⑷ to be 30°C, the membrane material is silicon carbide, the membrane hole is 0.04 μm, and the membrane module is a honeycomb coal-type inner tubular membrane. Microporous membrane equipment It was subjected to solid-liquid separation to separate out the insoluble aluminum phosphate precipitate, and 110.3 kg of the waste acid diluent of dealumination in the chemical polishing tank for aluminum profiles was obtained for use.

(6) Concentration and composition adjustment: Concentrate the diluted solution of dealumination waste acid in the chemical polishing tank of the aluminum profile obtained in step (5) to the moisture mass percentage of 13%, to obtain an aluminum profile chemical polishing tank dealumination solution with the main composition of phosphoric acid 42.9% (mass fraction), sulfuric acid 44.09% (mass fraction), moisture 13% (mass fraction) and aluminum ions 0.01% (mass fraction); According to the calculation, add 85% phosphoric acid and 98% sulfuric acid, so that the relative content of phosphoric acid is 73% (mass fraction) and the sulfuric acid content is 27% (mass fraction), that is, a recyclable chemical polishing tank acid solution is obtained. Chemical polishing for the next batch of aluminum profiles.

It has been determined that the phosphoric acid retention rate is 78% (22% phosphoric acid produces aluminum phosphate), the sulfuric acid retention rate is 100%, the aluminum ion removal rate is 99.9%, and the aluminum ion removal rate is 99.9%. The impurity removal rate is 100%, and the appearance is clear and transparent. The chemical polishing tank acid solution obtained by adjusting the composition of the dealumination acid solution in the chemical polishing tank for aluminum profiles can be used for the chemical polishing of the next batch of aluminum profiles.

Example 10:

A processing method for recycling waste acid of aluminum profile chemical polishing tank, the steps of which are:

(1) Dilution with water: take the main components as phosphoric acid 65% (mass fraction), sulfuric acid 11% (mass fraction), moisture 15% (mass fraction), aluminum ions 5.8% (mass fraction), copper ions 0.2% (mass fraction) and Insoluble impurities 3% (mass fraction) of aluminum profile chemical polishing tank waste acid 71.5 kg in a beaker, under the stirring condition of stirring speed of 130rpm, add reverse osmosis pure water 71.5 kg, for high concentration, high viscosity and turbid appearance of waste The acid was diluted, and the stirring was continued for 4 hours to obtain a waste acid dilution for use. The composition of waste acid diluent is phosphoric acid 32.5% (mass fraction), sulfuric acid 5.5% (mass fraction), moisture 57.5% (mass fraction), aluminum ion 2.9% (mass fraction), copper ion 0.1% (mass fraction) and insoluble Impurity 1.5% (mass fraction).

(2) Membrane separation: control step (1) The temperature of the obtained waste acid diluent is 25°C, and the waste acid is diluted by a microporous membrane device with a membrane material of silicon carbide, a membrane hole of 0.04 μm and a membrane module form of a honeycomb-type inner tubular membrane. The liquid was subjected to solid-liquid separation to separate out insoluble solids to obtain 142.9 kg of the membrane permeate of the waste acid diluent for use.

(3) Heating reaction: put the membrane permeate of the waste acid diluent obtained in step (2) into the heating reactor, turn on the cold water reflux, and under the stirring condition of the stirring speed of 70 rpm, heat it to 1100 ° C and maintain 110 ° C, continue The reaction was heated and stirred for 15 hours, so that phosphoric acid and aluminum ions were reacted to generate aluminum phosphate, and the reaction solution was obtained for subsequent use.

(4) Seed induction: take analytically pure non-crystalline aluminum phosphate, grind it with a stainless steel pulverizer, and sieve the pulverized material through a 200-mesh standard sieve to obtain aluminum phosphate seed crystals. Under the stirring condition of a stirring speed of 200 rpm, add aluminum phosphate crystal seeds with a mass fraction of 0.6% of the reaction solution to the reaction solution obtained in step (3), turn off the heating and let it naturally cool down to 25 ° C, and continue stirring for 19 hours to make aluminum phosphate crystal seeds. The aluminum phosphate in the reaction solution is induced to fully form an aluminum phosphate precipitate to obtain a reaction solution in which the aluminum phosphate is precipitated.

⑸ Membrane separation: control the temperature of the reaction solution obtained in step ⑷ to be 25°C, the membrane material is silicon carbide, the membrane hole is 0.1 μm, and the membrane module is a honeycomb type inner tubular membrane. Microporous membrane equipment It was subjected to solid-liquid separation to separate out the insoluble aluminum phosphate precipitate, and 141.6 kg of the waste acid diluent of dealumination in the chemical polishing tank for aluminum profiles was obtained for use.

(6) Concentration and composition adjustment: Concentrate the diluted solution of dealumination waste acid in the chemical polishing tank of the aluminum profile obtained in step (5) to the mass percentage of moisture by the forced circulation vacuum heating concentration method at a temperature of 85 ° C and a vacuum degree of 0.09 MPa. is 15%, and the main composition is phosphoric acid 45.5% (mass fraction), sulfuric acid 39.24% (mass fraction), moisture 15% (mass fraction), aluminum ions 0.01% (mass fraction) and copper ions 0.25% (mass fraction) Aluminum profile chemical polishing tank dealumination acid solution; add 85% phosphoric acid, 98% sulfuric acid and 66% nitric acid according to the calculation, so that the relative content of phosphoric acid is 65% (mass fraction) and the relative content of nitric acid is 14% (mass fraction) fraction) and the relative content of sulfuric acid is 11% (mass fraction), that is, a recyclable chemical polishing tank acid solution is obtained, which is used for the chemical polishing of the next batch of aluminum profiles.

It has been determined that the phosphoric acid retention rate is 70% (30% phosphoric acid produces aluminum phosphate), the sulfuric acid retention rate is 100%, the aluminum ion removal rate is 99.9%, and the aluminum ion removal rate is 99.9%. The impurity removal rate is 100%, and the appearance is clear and transparent. The chemical polishing tank acid solution obtained by adjusting the composition of the dealumination acid solution in the chemical polishing tank for aluminum profiles can be used for the chemical polishing of the next batch of aluminum profiles.

The specific embodiments described in this specification are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or additions to the described specific embodiments or substitute in similar manners, but will not deviate from the spirit of the present invention or go beyond the definitions of the appended claims range.

Claims (6)

1. a processing method of aluminum profile chemical polishing tank waste acid recycling, it is characterized in that: its step is: (1) Dilution by adding water: Take the waste acid of the chemical polishing tank for aluminum profiles in a strong acid-resistant container, and add pure water with a mass of 1.0 to 5.0 times the quality of the waste acid of the chemical polishing tank for aluminum profiles under stirring conditions. Dilute the waste acid in the chemical polishing tank of the aluminum profile, and continue to stir for 0.5 to 5 hours to obtain the waste acid diluent for use; (2) Membrane separation: control step (1) The temperature of the obtained waste acid diluent is 5-70 °C, and the waste acid diluent is solid-liquid separated with a microporous membrane device to separate insoluble solids, and the membrane permeation of the waste acid diluent is obtained. Liquid backup; (3) Heating reaction: put the membrane permeate of the waste acid diluent obtained in step (2) into a reactor or other container, turn on the cold water to reflux, stir continuously, heat it to the phosphoric acid dissociation reaction temperature and maintain the phosphoric acid dissociation reaction temperature, continue heating The reaction is stirred for 1.0 to 15 hours, and the phosphoric acid therein is reacted with the aluminum ion to generate aluminum phosphate, and the reaction solution is obtained for subsequent use; (4) Seed induction: take the solid aluminum phosphate and pulverize it with a stainless steel pulverizer. After the pulverized material is sieved through a standard sieve, aluminum phosphate seed crystals are obtained. Stir continuously, and add 0.05-5 mass fraction of the reaction solution to the reaction solution obtained in step (3) % aluminum phosphate seed crystals, turn off the heating and let it naturally cool down to 0-35°C, and continue to stir for 1.0-25 hours, so that the aluminum phosphate crystal seeds induce the aluminum phosphate in the reaction solution to fully form aluminum phosphate precipitation, and obtain aluminum phosphate precipitation. The reaction solution; ⑸Membrane separation: control the temperature of the reaction solution obtained in step ⑷ to be 5-70°C, and use microporous membrane equipment to separate solid-liquid, separate insoluble aluminum phosphate precipitate, and obtain aluminum profile chemical polishing tank The dealumination waste acid diluent is for use; (6) Concentration and composition adjustment: Concentrate the waste acid diluent of dealumination in the chemical polishing tank for aluminum profiles obtained in step (5) by the heating concentration method to a moisture content of 10-15% to obtain a dealumination acid solution in the chemical polishing tank for aluminum profiles; analysis Measure the content of phosphoric acid and sulfuric acid, and add the acid solution according to the mass percentage of each acid solution in the chemical polishing tank for chemically polished aluminum profiles to obtain the recycled chemical polishing tank acid solution. 2. the processing method of a kind of aluminum profile chemical polishing tank waste acid recycling according to claim 1, it is characterized in that: the aluminum profile chemical polishing tank waste acid in the described step (1) is used for aluminum profile chemical polishing The main components of the mixed acid solution are: phosphoric acid 40-60% mass fraction, sulfuric acid 20-40% mass fraction, aluminum ion 2-6% mass fraction and moisture 8-20% mass fraction; the pure water refers to reverse osmosis method pure water, ion exchange method pure water and distillation condensation method pure water with conductivity lower than 10 ^-3 s/m water. 3. the processing method of a kind of aluminum profile chemical polishing tank waste acid recycling according to claim 1, is characterized in that: the microporous membrane equipment in described step (2), step (5), its membrane material is silicon carbide, The form of the membrane module is a honeycomb type inner tubular membrane, and the membrane pore size is 1, 0.5, 0.1 and 0.04 μm. 4. the processing method that a kind of aluminum profile chemical polishing tank waste acid recycling according to claim 1 is used, it is characterized in that: the phosphoric acid dissociation reaction temperature in described step (3) is the temperature that can promote aluminum phosphate to generate, and its scope It is 35～120 ℃. 5. the processing method of a kind of aluminum profile chemical polishing tank waste acid recycling according to claim 1, it is characterized in that: the solid aluminum phosphate in the described step (4) is analytically pure or chemically pure no crystal water or has The aluminum phosphate crystal of crystal water; the standard sieve is sieved, and the size of the standard sieve is 40-600 mesh. 6. the processing method of a kind of aluminum profile chemical polishing tank waste acid recycling according to claim 1, is characterized in that: the heating concentration method in described step (6) is forced circulation vacuum concentration method or rising-falling film concentration Law.

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