Environment-friendly residual titanium composite cleaning agent and use method thereof

Abstract

The invention discloses an environment-friendly residual titanium composite cleaning agent and a use method thereof, and belongs to the technical field of titanium recovery. In order to solve the problems of an existing residual titanium cleaning process, the environment-friendly residual titanium composite cleaning agent and the cleaning use method are developed, the environment-friendly residual titanium composite cleaning agent is a mixed aqueous solution of caustic alkali and Na4P2O7, the concentration of the caustic alkali is 10-50 g / L, and the concentration of the Na4P2O7 is 10-40 g / L; under the ultrasonic condition, the composite cleaning agent is used for cleaning residual titanium, and then water washing and drying are conducted. The caustic alkali and the Na4P2O7 are compounded, the dosage of the caustic alkali and the dosage of the Na4P2O7 are optimized, efficient oil removal and impurity removal of the residual titanium are achieved under the low alkalinity through the synergistic effect of saponification and microwave dispersion, the content of pollutants on the surface of the residual titanium is remarkably reduced, the removal rate of the element O of the residual titanium is larger than or equal to 60%, the removal rate of the element N is larger than or equal to 97%, and the removal rate of the element C is larger than or equal to 98%; the method has the advantages of low cost, simple operation, environmental friendliness and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium recovery, and particularly relates to an environmentally friendly residual titanium composite cleaning agent and a use method thereof. Background Art

[0002] Titanium and its alloys are widely used due to their excellent specific strength, corrosion resistance, and biocompatibility. However, their high energy consumption and high cost of production have made the recovery of residual titanium, such as titanium cuttings, a research hotspot. However, the surface of residual titanium often contains contaminants such as cutting oil (primarily composed of hydrocarbons), resulting in increased levels of impurities such as O, N, and C in the recovered titanium product, seriously affecting the titanium alloy's processing plasticity and oxidation resistance. Therefore, cleaning has become a key step in the recovery or reuse of residual titanium.

[0003] Generally speaking, cleaning methods for residual titanium include mechanical cleaning, electrolytic cleaning, and chemical cleaning. Mechanical cleaning methods, such as sandblasting and brushing, are primarily used to remove large deposits on the surface of residual titanium (such as oxide layers, oil stains, and coatings). Electrolytic cleaning deeply removes oxide layers through electrochemical reactions. Chemical cleaning involves immersing the residual titanium in acidic, alkaline, or organic cleaning agents and is preferred for removing cutting oils. Acidic cleaning agents include nitric acid and hydrofluoric acid. Nitric acid (concentration: 10% to 30%) is highly effective in removing oxide layers, but may cause surface passivation. Hydrofluoric acid (concentration: 1% to 5%), often mixed with nitric acid, can also quickly dissolve titanium oxides, but is highly toxic and requires strict precautions. Alkaline cleaning agents, such as sodium hydroxide and sodium bicarbonate, are mild, but their degreasing effectiveness when used alone is limited, with low carbon impurity removal rates. Organic cleaning agents, such as acetone / ethanol, can be used for preliminary removal of oil stains or organic coatings, but are flammable and explosive.

[0004] CN103480597A discloses a method for cleaning residual titanium. The residual titanium is placed in a cleaning tank and cleaned using weak alkaline water (at a concentration of 2%-10%) under the action of ultrasonic waves at a frequency of 20-130 kHz. After cleaning, the system automatically transfers the weak alkaline water to a storage tank and circulates clean water to rinse the residual titanium. This method focuses on ultrasonic cleaning of the residual titanium and does not consider the impact of cleaning agents on the cleaning effect. Furthermore, the method uses a single alkaline wash, resulting in limited degreasing effectiveness and a low carbon impurity removal rate.

[0005] CN112941365A discloses a method for recovering residual titanium to produce high-performance powder metallurgy titanium and titanium alloys. The method involves ultrasonically cleaning the residual titanium in an organic solvent such as dichloromethane, chloroform, acetone, alcohol, or xylene for 8 to 24 hours. This method also uses only a single organic solvent for cleaning, which can only preliminarily remove oil stains or organic coatings and poses potential flammability and explosion hazards.

[0006] CN119876618A discloses a method for recovering TC4 waste. The method first uses an alkaline solution to wash the TC4 waste to remove oil stains on its surface, and then uses an acidic solution to pickle the waste to remove the oxide layer on its surface. This method, which uses a single base or acid for cleaning, also suffers from the aforementioned problems. While it can improve the removal rate of impurities such as C, N, and O in the residual titanium to a certain extent, the improvement is limited. Furthermore, the cleaning process is lengthy and requires the use of relatively high concentrations of alkaline or acidic solutions, generating large amounts of waste acid and alkali.

[0007] Therefore, there is an urgent need to develop a safe, environmentally friendly and efficient residual titanium cleaning agent and a method for using the same. Summary of the Invention

[0008] To solve the above problems, the present invention has developed an environmentally friendly residual titanium composite cleaning agent and a method of use thereof. By using a low-alkaline composite solution (caustic soda + tetrasodium pyrophosphate) in conjunction with microwave cleaning, the content of impurity elements such as C, N, and O in residual titanium can be significantly reduced.

[0009] The present invention provides an environmentally friendly residual titanium composite cleaning agent, which is a mixed aqueous solution of caustic alkali and Na4P2O7 (tetrasodium pyrophosphate), the concentration of the caustic alkali is 10-50g / L, the concentration of Na4P2O7 is 10-40g / L, and the caustic alkali is sodium hydroxide or potassium hydroxide.

[0010] Preferably, in the above-mentioned environmentally friendly residual titanium composite cleaning agent, the concentration of caustic soda is 10-20 g / L.

[0011] Preferably, in the above-mentioned environmentally friendly residual titanium composite cleaning agent, the concentration of Na4P2O7 is 30-40 g / L.

[0012] The present invention also provides a method for using the above-mentioned environmentally friendly residual titanium composite cleaning agent, which comprises the following steps:

[0013] A. Separate the residual titanium material into block material and chip material, and obtain the screened material after the chip material is crushed and screened;

[0014] B. Under ultrasonic conditions, use the above-mentioned environmentally friendly residual titanium composite cleaning agent to clean the screening material, or clean the bulk material, or clean the mixture of the screening material and the bulk material;

[0015] C. The cleaned material is washed with water and dried.

[0016] Wherein, in the above-mentioned method of use, in step A, the crushing is crushing to a particle size of ≤50mm.

[0017] Wherein, in the above-mentioned method of use, in step A, the particle size of the obtained sieved material is 5 to 15 mm.

[0018] In the above method of use, in step B, the amount of the composite cleaning agent used is based on the requirement to completely immerse the material to be cleaned.

[0019] Preferably, in the above-mentioned method of use, in step B, the volume-to-mass ratio of the composite cleaning agent to the material to be cleaned is 0.8-1.2 L:1 kg.

[0020] Wherein, in the above-mentioned method of use, in step B, the frequency of the ultrasound is 20 to 80 kHz, and the power is 500 to 2000 W.

[0021] Wherein, in the above-mentioned method of use, in step B, the cleaning time is 10 to 20 minutes.

[0022] Wherein, in the above-mentioned method of use, in step C, the drying temperature is 80-100°C.

[0023] Wherein, in the above-mentioned method of use, in step C, the drying time is 5 to 10 minutes.

[0024] Beneficial effects of the present invention:

[0025] The present invention uses a compound of caustic soda and Na4P2O7, with the dosage of both being optimized. Through the synergistic effect of saponification reaction and microwave dispersion, the content of surface pollutants of residual titanium can be significantly reduced at low alkalinity, achieving efficient degreasing and impurity removal of residual titanium. The cleaning process proposed by the present invention is low in alkalinity, acid-free, and free of organic solvents, safe and environmentally friendly, and in line with the trend of green manufacturing. Through the present invention, the O element removal rate of residual titanium is ≥60%, the N element removal rate is ≥97%, and the C element removal rate is ≥98%. After cleaning, the titanium chips can be directly used for smelting to prepare titanium alloys or low-impurity titanium-iron alloys. The present invention can be widely used in titanium processing enterprises, metal recycling plants, and the field of special alloy manufacturing, and has the advantages of low cost, simple operation, and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the cleaning process using the environmentally friendly residual titanium composite cleaning agent of the present invention. DETAILED DESCRIPTION

[0027] Specifically, an environmentally friendly residual titanium composite cleaning agent is a mixed aqueous solution of caustic alkali and Na4P2O7, the concentration of caustic alkali is 10-50g / L, the concentration of Na4P2O7 is 10-40g / L, and the caustic alkali is sodium hydroxide or potassium hydroxide.

[0028] The present invention can achieve excellent cleaning effects at low alkalinity, so the concentration of caustic soda in the environmentally friendly residual titanium composite cleaning agent of the present invention is preferably 10 to 20 g / L.

[0029] According to experiments, appropriately increasing the concentration of tetrasodium pyrophosphate can significantly improve the removal rate of C, O, and N. Therefore, the concentration of Na4P2O7 in the environmentally friendly residual titanium composite cleaning agent of the present invention is preferably 30-40 g / L.

[0030] The present invention also provides a method for using the above-mentioned environmentally friendly residual titanium composite cleaning agent, which comprises the following steps:

[0031] A. Separate the residual titanium material into block material and chip material, and obtain the screened material after the chip material is crushed and screened;

[0032] B. Under ultrasonic conditions, use the above-mentioned environmentally friendly residual titanium composite cleaning agent to clean the screening material, or clean the bulk material, or clean the mixture of the screening material and the bulk material;

[0033] C. The cleaned material is washed with water and dried.

[0034] In step A of the present invention, the crushing is crushing to a particle size of ≤50 mm. Crushing can be performed using conventional equipment in the art, for example, a hammer crusher is generally used to pre-crush the particles to a particle size of ≤50 mm.

[0035] In step A of the present invention, the particle size of the screened material obtained is 5 to 15 mm. Screening can be performed using conventional equipment in the art, for example, a vibrating screen is generally used to obtain a screened material with a particle size of 5 to 15 mm.

[0036] In step B of the present invention, the frequency of the ultrasound is 20 to 80 kHz, and the power is 500 to 2000 W. Conventional equipment in the art can be used for ultrasonic cleaning, such as an ultrasonic cleaning machine.

[0037] In step B of the present invention, the cleaning time is 10 to 20 minutes.

[0038] In step C of the present invention, the drying temperature is 80-100°C.

[0039] In step C of the present invention, the drying time is 5 to 10 minutes.

[0040] The present invention is further described in detail below through examples, but the protection scope of the present invention is not limited to the scope of the examples.

[0041] Example 1

[0042] This embodiment uses the cleaning agent of Table 2 to clean residual titanium, which specifically includes the following steps:

[0043] Step 1: Take a certain amount of residual titanium material in the form of chips, the contents of impurity elements C, O, and N of which are shown in Table 1, and crush it to a particle size of ≤50 mm using a hammer crusher. Then pass it through a vibrating screen to obtain residual titanium screening material with a particle size of 5 to 15 mm, totaling 100 kg, and place it in the cleaning tank of an ultrasonic cleaning machine.

[0044] Step 2: Prepare a low-alkaline composite cleaning agent. Take 100L of pure water, add NaOH and Na4P2O7 according to the ratio in Table 2, stir thoroughly to completely dissolve them, and then add them to the cleaning tank of the ultrasonic cleaning machine to immerse all the residual titanium screening materials.

[0045] Step 3: Start the ultrasonic cleaning machine, with an ultrasonic frequency of 60kHz, a power of 1000W, and a cleaning time of 12 minutes.

[0046] Step 4: Take out the cleaned residual titanium material and rinse it with pure water to remove the residual cleaning agent.

[0047] Step 5: Place the rinsed residual titanium material into a hot air blower and dry it at 100°C for 10 minutes.

[0048] Step 6: Take out the dried residual titanium material and remove ferromagnetic impurities through a magnetic separator.

[0049] Comparative Examples 1 to 3 are set to study the effect of the amount of NaOH added (alkalinity) on the cleaning effect of residual titanium when no Na4P2O7 is added to the cleaning agent; Examples 1 to 4 are set to study the effect of the amount of Na4P2O7 added on the cleaning effect of residual titanium when the amount of NaOH added is low.

[0050] Table 1 Impurity element content of residual titanium material (mass percentage / ppm)

[0051] element C O N Content (ppm) 20653 3124 617

[0052] Table 2 Residual titanium material cleaning agent formula (g / L)

[0053] cleaning agent Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 Example 4 NaOH 20 40 80 20 20 20 20 <![CDATA[Na4P2O7]]> 0 0 0 10 20 30 40

[0054] Table 3 Cleaning effect of residual titanium material under different process conditions

[0055]

[0056] As can be seen from Table 3, when no Na₄P₂Oₐ is added to the cleaning agent, the cleaning effect of residual titanium improves with increasing the amount of NaOH added, that is, the alkalinity of the cleaning agent (Comparative Examples 1-3). When the amount of NaOH added is 20 g / L (low alkalinity), the removal rates of C, O, and N after residual titanium cleaning are 45.62%, 32.33%, and 29.82%, respectively. When the amount of NaOH added is 80 g / L (high alkalinity), the removal rates of C, O, and N after residual titanium cleaning are 83.01%, 49.97%, and 76.18%, respectively. However, when a certain amount of Na₄P₂Oₐ is added, the cleaning agent can achieve a high degree of residual titanium cleaning at a lower alkalinity (NaOH addition of 20 g / L), significantly improving the removal rates of C, O, and N. Compared to Comparative Example 1 (20 g / L NaOH + 0 g / L Na4P2O7), the cleaning removal rates of residual titanium C, O, and N in Example 1 (20 g / L NaOH + 10 g / L Na4P2O7) were significantly improved to 92.38%, 60.15%, and 89.63%. In addition, as the amount of Na4P2O7 added increased, the removal rates of residual titanium C, O, and N continued to increase. However, when the amount of Na4P2O7 added reached 40 g / L, the C, O, and N removal rates only increased slightly. The addition of 40 g / L Na4P2O7 has basically reached the cleaning limit, and further increasing the amount of Na4P2O7 added will not significantly change the cleaning effect. The above results show that the present invention can achieve efficient degreasing and impurity removal of residual titanium materials without using a strong alkaline solution.

Claims

1. Environmentally friendly residual titanium composite cleaning agent, characterized by: The composite cleaning agent is a mixed aqueous solution of caustic alkali and Na4P2O7, the concentration of the caustic alkali is 10-50g / L, the concentration of Na4P2O7 is 10-40g / L, and the caustic alkali is sodium hydroxide or potassium hydroxide.

2. The environmentally friendly residual titanium composite cleaning agent according to claim 1, characterized in that: The concentration of caustic soda is 10-20 g / L.

3. The environmentally friendly residual titanium composite cleaning agent according to claim 1 or 2, characterized in that: The concentration of Na4P2O7 is 30-40g / L.

4. The method for using the environmentally friendly residual titanium composite cleaning agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: A. Separate the residual titanium material into block material and chip material, and obtain the screened material after the chip material is crushed and screened; B. Under ultrasonic conditions, use the environmentally friendly residual titanium composite cleaning agent according to any one of claims 1 to 3 to clean the screening material, or clean the bulk material, or clean the mixture of the screening material and the bulk material; C. The cleaned material is washed with water and dried.

5. The method of use according to claim 4, characterized in that: In step A, the crushing is to crush to a particle size of ≤50 mm.

6. The method of use according to claim 4, characterized in that: In step A, the particle size of the obtained sieved material is 5 to 15 mm.

7. The method of use according to claim 4, characterized in that: In step B, the amount of the composite cleaning agent used is based on completely immersing the material to be cleaned; preferably, the volume-to-mass ratio of the composite cleaning agent to the material to be cleaned is 0.8-1.2 L:1 kg.

8. The method of use according to claim 4, characterized in that: In step B, the frequency of the ultrasound is 20 to 80 kHz, and the power is 500 to 2000 W.

9. The method of use according to claim 4, characterized in that: In step B, the cleaning time is 10 to 20 minutes.

10. The method of use according to any one of claims 4 to 9, characterized in that: In step C, the drying temperature is 80-100° C., and the drying time is 5-10 minutes.

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