Aluminum alloy cutting waste liquid regeneration treatment method

Abstract

The invention discloses an aluminum alloy cutting waste liquid regeneration treatment method. The method comprises the steps of rough filtration, fine filtration, sterilization, activation, fine filtration and adjustment on cutting waste liquid. The specific activation method comprises the following steps: firstly, adding concentrated hydrochloric acid into the sterilized initial cutting waste liquid to adjust the pH value to 5.5-6.5, and then adding sodium hydroxide to adjust the pH value to 8-9.8; the specific adjustment method comprises the following steps: supplementing and adding a nonionic surfactant accounting for 1.5-6% of the weight of the cutting fluid or a mixture of the nonionic surfactant and an extreme pressure agent accounting for 1.5-6% of the weight of the cutting fluid into the cutting fluid subjected to refined filtration treatment to obtain the new cutting fluid. According to the invention, the problems of reduction or loss of lubrication, rust prevention and other properties of the cutting waste liquid due to loss of the activity of the anionic surfactant are solved, and efficient recycling of the cutting liquid is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of cutting waste liquid treatment, and more specifically, to a method for regenerating and treating aluminum alloy cutting waste liquid. Background Art

[0002] Cutting fluid plays the role of cooling, lubricating, anti-corrosion and cleaning in metal machining. Used cutting fluid contains metal debris, miscellaneous oil, microorganisms, etc., with complex ingredients and easy to deteriorate, making it difficult to reuse. In addition, a large amount of initial cutting waste fluid is difficult to handle, which also brings environmental problems.

[0003] In addition, most of the cutting fluids commonly used in industry are water-based cutting fluids, and water-based cutting fluids mostly use anionic surfactants. After processing aluminum alloy parts, the cutting fluid contains cations such as aluminum ions (Al3+), magnesium ions (Mg2+), and iron ions (Fe3+). Some cations and anionic surfactants will form stearates. This type of soap is difficult to dissolve in water, resulting in the inactivation of anionic surfactants, which reduces or loses the emulsification and rust prevention properties of the cutting fluid; this type of cation is also easy to form an emulsified paste layer with floating oil in the cutting fluid, and other dust, microorganisms, impurities and other substances make the cutting fluid turbid, which further leads to difficulties in the reuse of the cutting fluid and increased waste fluid discharge.

[0004] In the prior art, waste cutting fluid is often treated and reused by precipitation, filtration, sterilization and other methods. However, due to the inactivation of surfactants in cutting fluid, the emulsification, lubrication, rust prevention, cleaning and other properties of cutting fluid are significantly reduced. The existing technology and treatment methods cannot solve the problem of inactivation of cutting fluid surfactants, and there is currently no technical solution that can improve the performance of cutting waste fluid and achieve reuse. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a method for regenerating aluminum alloy cutting waste fluid, which solves the problem of reduction or loss of lubrication, rust prevention and other properties of the cutting waste fluid due to the loss of activity of anionic surfactants, and realizes the efficient reuse of the cutting fluid.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for regenerating and treating aluminum alloy cutting waste liquid, comprising the steps of coarse filtration, fine filtration, sterilization, activation, fine filtration and adjustment of the cutting waste liquid;

[0008] The specific activation method is: firstly, add concentrated hydrochloric acid to the sterilized initial cutting waste liquid to adjust the pH value to 5.5-6.5, and then add sodium hydroxide to adjust the pH value to 8-9.8;

[0009] The specific adjustment method is: add 1.5-6% of the weight of the cutting fluid or 1.5-6% of the weight of the cutting fluid and a mixture of an extreme pressure agent to the cutting fluid after fine filtration to obtain a new cutting fluid.

[0010] Furthermore, the nonionic surfactant is at least one of maleic anhydride rosin triethanol ester, oleic acid triethanolamine, nonionic surfactant 607, and water-soluble polyether ester.

[0011] Furthermore, the specific method of coarse filtration is: allowing the initial cutting waste liquid after cutting to settle, separating the precipitate and filtering it to remove particles with a particle size greater than 1500 μm in the waste liquid.

[0012] Furthermore, the specific method of fine filtration is: fine filtration is performed on the cutting fluid after coarse filtration through a non-woven fabric to filter out the sediment and particles with a size of 20-1500 μm in the cutting fluid.

[0013] Furthermore, the specific sterilization method is: subjecting the finely filtered initial cutting waste liquid to ozone and UV ultraviolet light sterilization treatment for 2.5-3.5 hours.

[0014] Furthermore, the specific method of fine filtration is: centrifugally separate and finely filter the activated cutting fluid to remove particles larger than 5 μm in the cutting fluid.

[0015] Furthermore, the initial cutting waste fluid is a cutting fluid containing anionic surfactant formed after cutting, and contains 10-50wt% of base oil and 10-20wt% of additives.

[0016] Furthermore, the base oil is mineral oil, and the additive is a mixture of an extreme pressure agent, a rust inhibitor, a coolant, an anionic surfactant, a bactericide, and a defoaming agent.

[0017] The beneficial effects of the present invention are:

[0018] By coarse filtration, fine filtration, sterilization, activation, fine filtration and adjustment of the cutting waste fluid, a new cutting fluid with good lubricity, stability and rust resistance is obtained, which solves the problem of reduction or loss of lubrication, rust resistance and other properties of the cutting waste fluid due to the loss of activity of the anionic surfactant, realizes the efficient reuse of the cutting fluid, and can be widely used in the regeneration treatment of various cutting waste fluids. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The aluminum alloy cutting waste liquid regeneration treatment method of the present invention comprises the steps of coarse filtration, fine filtration, sterilization, activation, fine filtration and adjustment.

[0021] (a) Coarse filtration The specific method is: inject the initial cutting waste liquid after cutting into a sedimentation tank for static sedimentation to separate impurities such as debris, and then filter the cutting waste liquid through a 200-mesh filter to remove particles with a particle size greater than 1500 μm in the waste liquid.

[0022] The initial cutting waste fluid is a cutting fluid containing anionic surfactant formed after cutting processing, which contains 10-50wt% base oil and 10-20wt% additives; the base oil is mineral oil, and the additives are a mixture of extreme pressure agent, rust inhibitor, coolant, anionic surfactant, bactericide, and defoamer.

[0023] The anionic surfactant is selected from at least one of higher fatty acid salts (such as fatty acid methyl ester sulfonate, triethanolamine stearate, etc.), sulfates (such as sodium lauryl sulfate, polyoxyethylene lauryl ether sulfate sodium salt, etc.), and sulfonates (sodium lauryl sulfonate, etc.).

[0024] (b) Fine filtration The specific method is: fine filter the cutting fluid after coarse filtration through a non-woven filter to filter out the sediment and particles with a size of 20-1500 μm in the cutting fluid.

[0025] (c) The specific sterilization method is as follows: inject the finely filtered initial cutting waste liquid into a sterilization tank, and perform ozone and UV ultraviolet light sterilization treatment for 2.5-3.5 hours to remove anaerobic bacteria, facultative anaerobic bacteria and other microorganisms in the cutting fluid; after the sterilization is completed, measure the pH value of the cutting waste liquid; a tee is installed on the top of the sterilization tank, and the tee is a straight tee or an oblique tee, and its main pipeline extends into the sterilization tank, and a drying adsorption bag is set at the outlet of the branch pipeline to dry the gas and absorb the odor during the aeration process.

[0026] (d) Activation The specific method is: add concentrated hydrochloric acid to the sterilized initial cutting waste liquid, stir and mix, adjust the pH value to 5.5-6.5, then add sodium hydroxide, stir and mix, and adjust the pH value to 8-9.8.

[0027] The amount of concentrated hydrochloric acid added is calculated as follows: Wherein, V1 is the volume of hydrochloric acid to be added, in L; a is the concentration of hydrochloric acid, in mol / L; V is the volume of the initial cutting waste liquid after sterilization.

[0028] The amount of sodium hydroxide added is calculated based on the pH value before and after the addition of sodium hydroxide to the cutting waste fluid, the volume of the cutting fluid, and the concentration of sodium hydroxide; the method for calculating the amount of sodium hydroxide added is the same as the method for calculating the amount of hydrochloric acid added.

[0029] In this operation, concentrated hydrochloric acid and sodium hydroxide are added to the sterilization tank through a three-way pipe; hydrochloric acid can neutralize the alkaline substances in the cutting waste liquid, and undergo a replacement reaction with aluminum, magnesium, etc. to form chloride salts such as aluminum ions, magnesium ions, and calcium ions); sodium hydroxide can neutralize the hydrochloric acid in the cutting waste liquid, and undergo a neutralization reaction with the carboxylic acid compounds therein to generate carboxylic acid anions (R-COO - ), forming a water-in-oil type molecular structure again, which improves the surface activity of the cutting fluid, and the sodium hydroxide can react chemically with the aluminum salt, magnesium salt, etc. in the cutting waste fluid, making the original aluminum ion (Al 3+ ), magnesium ion (Mg 2+ ), iron ions (Fe 3+ ) and other cations are removed in the form of precipitation such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide.

[0030] (e) Fine filtration The specific method is: use a centrifugal separator to centrifuge and fine filter the activated cutting fluid to filter out particles larger than 5 μm in the cutting fluid.

[0031] (f) The specific adjustment method is: inject the cutting fluid after fine filtration into the adjustment tank, add 1.5-6% of the weight of the cutting fluid non-ionic surfactant or 1.5-6% of the weight of the cutting fluid non-ionic surfactant and extreme pressure agent (the extreme pressure agent is preferably bis(dimethylamino) cardanol phosphate, and the synthesis method refers to the paper: Synthesis and Tribological Properties of Bis(dimethylamino) Cardanol Phosphate Type Anti-wear Extreme Pressure Agent [J]. Wei Kecheng; Chen Xiaowei. Synthetic Lubricating Materials, Vol. 47, No. 3, 2020) into the adjustment tank, stir and mix to obtain a new cutting fluid; the non-ionic surfactant is selected from at least one of maleic anhydride rosin triethanolamine, oleic acid triethanolamine, non-ionic surfactant 607 (purchased from Sichuan Ruikaibang Chemical Materials Co., Ltd.), and water-soluble polyether ester.

[0032] The preferred embodiments are as follows:

[0033] Example 1

[0034] (a) Coarse filtration: The initial cutting waste liquid after cutting is injected into a sedimentation tank for static sedimentation to separate impurities such as debris, and then the cutting waste liquid is filtered through a 200-mesh filter to remove particles with a particle size greater than 1500 μm. The initial cutting waste liquid is formed by a cutting fluid containing an anionic surfactant (the cutting fluid contains the following components in percentage by mass: 40% mineral oil, 5% phosphate, 2% diethanolamine, 1% ethylene glycol, 2% sodium dodecylbenzene sulfonate, 1% benzisothiazolinone, 0.5% polypropylene glycol, 48.5% water) after cutting.

[0035] (b) Fine filtration: The cutting fluid after coarse filtration is finely filtered through a non-woven filter to remove the sediment and particles with a size of 20-1500μm in the cutting fluid.

[0036] (c) The specific sterilization method is as follows: the finely filtered initial cutting waste liquid is injected into a sterilization tank for 3 hours of ozone and UV sterilization treatment to remove anaerobic bacteria, facultative anaerobic bacteria and other microorganisms in the cutting fluid; after the sterilization is completed, the pH value of the cutting waste liquid is measured.

[0037] (d) Activation: The specific method is as follows: add concentrated hydrochloric acid to the sterilized initial cutting waste liquid, stir for 0.5 h, adjust the pH value to 6, then add sodium hydroxide, stir for 0.5 h, and adjust the pH value to 8.

[0038] (e) Fine filtration The specific method is: use a centrifugal separator to centrifuge and fine filter the activated cutting fluid to filter out particles larger than 5 μm in the cutting fluid.

[0039] (f) The specific method of adjustment is: inject the finely filtered cutting fluid into an adjustment tank, add 5% of the weight of the cutting fluid into the adjustment tank (2.5% maleic anhydride rosin triethanolamine, 2.5% oleic acid triethanolamine), stir and mix, and obtain new cutting fluid.

[0040] Example 2

[0041] Aluminum alloy cutting waste fluid is regenerated according to the method of Example 1, except that: in step (f), 2.5% of triethanolamine oleate and 2.5% of non-ionic surfactant 607 are added to the cutting fluid after fine filtration.

[0042] Example 3

[0043] The aluminum alloy cutting waste fluid is regenerated according to the method of Example 1, except that: in step (f), 2.5% of triethanolamine oleate by weight of the cutting fluid and 2.5% of bis(dimethylamino) cardanol phosphate by weight of the cutting fluid are added to the cutting fluid after fine filtration.

[0044] Example 4

[0045] The aluminum alloy cutting waste fluid is regenerated according to the method of Example 1, except that: in step (f), 2.5% of the weight of the cutting fluid of the non-ionic surfactant 607 and 2.5% of the weight of the cutting fluid of the bis(dimethylamino) cardanol phosphate are added to the cutting fluid after fine filtration.

[0046] Sodium dodecylbenzene sulfonate in Example 1-Example 4 belongs to anionic surfactants. During the cutting process, the cutting fluid containing the modified anionic surfactant ionizes the negatively charged alkyl sulfonate ions in the solution, which are adsorbed on the positively charged aluminum ion surface by electrostatic action, that is, the hydrophilic group is toward the aluminum surface and the hydrophobic group is toward the aluminum medium. The anionic surfactant and the surface of the aluminum alloy part undergo adsorption loss; as the cations such as aluminum ions and magnesium ions in the cutting fluid increase, the anionic surfactant loses its activity. After the cutting waste fluid is coarsely filtered, finely filtered, and sterilized, after hydrochloric acid is added to the cutting waste fluid, sodium dodecylbenzene sulfonate reacts with hydrochloric acid to generate dodecylbenzene sulfonic acid and sodium chloride, and hydrochloric acid reacts with aluminum, magnesium, etc. in the solution to generate chloride salts such as aluminum chloride and magnesium chloride. After the subsequent addition of sodium hydroxide solution, these chloride salts such as aluminum chloride and magnesium chloride generate precipitation and are filtered and removed. Dodecylbenzene sulfonic acid and sodium hydroxide undergo acid-base neutralization reaction to form sodium dodecylbenzene sulfonate, so that the anionic surfactant is restored to activity.

[0047] The new cutting fluid obtained in Examples 1 to 4 was tested for performance, and the results are shown in Table 1. It can be seen that after the nonionic surfactant 607 and bis(dimethylamino) cardanol phosphate are compounded, the nonionic surfactant 607 and bis(dimethylamino) cardanol phosphate play a synergistic role, and the cutting fluid has better lubricity, stability and cycle life, and can further improve the cutting processing accuracy.

[0048] Table 1

[0049]

[0050] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for regenerating aluminum alloy cutting waste liquid, characterized in that: It includes the steps of coarse filtration, fine filtration, sterilization, activation, fine filtration and adjustment of the cutting waste fluid; The specific activation method is: firstly, add concentrated hydrochloric acid to the sterilized initial cutting waste liquid to adjust the pH value to 5.5-6.5, and then add sodium hydroxide to adjust the pH value to 8-9.8; The specific adjustment method is: add 1.5-6% of the weight of the cutting fluid or 1.5-6% of the weight of the cutting fluid and a mixture of an extreme pressure agent to the cutting fluid after fine filtration to obtain a new cutting fluid.

2. The method for regenerating aluminum alloy cutting waste fluid according to claim 1, characterized in that: The nonionic surfactant is at least one of maleic anhydride rosin triethanol ester, oleic acid triethanolamine, nonionic surfactant 607, and water-soluble polyether ester.

3. The method for regenerating aluminum alloy cutting waste fluid according to claim 1, characterized in that: The specific method of coarse filtration is: the initial cutting waste liquid after cutting processing is allowed to settle, the precipitate is separated and then filtered to remove particles with a particle size greater than 1500 μm in the waste liquid.

4. The method for regenerating aluminum alloy cutting waste fluid according to claim 1, characterized in that: The specific method of fine filtration is: the cutting fluid after coarse filtration is finely filtered through non-woven fabric to filter out the sediment and particles with a size of 20-1500μm in the cutting fluid.

5. The method for regenerating aluminum alloy cutting waste fluid according to claim 1, characterized in that: The specific sterilization method is: subjecting the finely filtered initial cutting waste liquid to ozone and UV ultraviolet light sterilization for 2.5-3.5 hours.

6. The method for regenerating aluminum alloy cutting waste fluid according to claim 1, characterized in that: The specific method of fine filtration is: centrifuge the activated cutting fluid for fine filtration to remove particles larger than 5μm in the cutting fluid.

7. A method for regenerating aluminum alloy cutting waste fluid according to any one of claims 1 to 6, characterized in that: The initial cutting waste fluid is formed after the cutting fluid containing anionic surfactant is processed by cutting, and contains 10-50wt% of base oil and 10-20wt% of additives.

8. The method for regenerating aluminum alloy cutting waste fluid according to claim 7, characterized in that: The base oil is mineral oil, and the additives are a mixture of extreme pressure agent, rust inhibitor, coolant, anionic surfactant, bactericide and defoaming agent.

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