Method for early warning concentration of bath solution of aluminum alloy chemical milling bath

Abstract

The invention discloses an aluminum alloy chemical milling tank liquid concentration early warning method, which comprises the following steps of: counting the monthly milling amount and the annual milling amount of aluminum through a monitoring device of a crane so as to obtain the monthly consumption amount and the annual consumption amount of sodium hydroxide in a chemical milling tank; especially, a chemical milling tank liquid concentration early-warning device, a feeding tank liquid level early-warning device and a tank pouring early-warning device are arranged, so that sodium hydroxide can be supplied and blended at any time, and the remaining amount of sodium hydroxide can be recognized in advance. The method is clear in process and high in early warning capacity, the components of the bath solution are stabilized, the production quality is guaranteed, and the working efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the field of chemical solution preparation and relates to a method for early warning of groove liquid concentration in chemical milling of aluminum alloys. Background Art

[0002] Aluminum alloy chemical milling (abbreviated as chemical milling) is a special processing method that uses chemical corrosion and is widely used in the aviation field. Generally, the effective range of sodium hydroxide solution for aluminum alloy chemical milling solution is 120-195g / L. As chemical milling production proceeds, due to the continuous dissolution of aluminum alloy, the concentration of sodium hydroxide will gradually decrease, resulting in the corrosion rate of chemical milling grooves being lower than the optimal corrosion rate, which prolongs the chemical milling processing time and the corrosion time cannot be guaranteed, thus affecting product quality. In addition, the procurement cycle of chemicals is long, which often affects production stagnation and causes production cycles. Summary of the invention

[0003] The purpose of the present invention is to provide a method for early warning of grooving liquid concentration in chemical milling grooving of aluminum alloys, so as to solve the problem that changes in grooving liquid concentration and untimely purchase of drugs affect production quality and production cycle during the production process of chemical milling grooving liquid.

[0004] A method for early warning of slot liquid concentration in chemical milling of aluminum alloys, comprising the following steps:

[0005] First, design an early warning system in the chemical milling slot:

[0006] A weight monitoring device is provided on the crane used to lift the aluminum alloy into the chemical milling slot. Each time the aluminum alloy is lifted, the weight monitoring device is turned on to calculate the accumulated milling amount of the aluminum alloy; wherein the milling amount is the difference in mass of the aluminum alloy before and after entering the chemical milling slot;

[0007] It is set that when the milling amount of aluminum alloy reaches the preset value A, the monitoring device of the crane starts the early warning; the calculation formula of A is:

[0008] A=27*v*ρ / 40

[0009] In the above formula, v represents the volume of the chemical milling slot, and ρ is the concentration of sodium hydroxide after the chemical milling slot is produced and prepared;

[0010] According to the sodium hydroxide concentration after production and deployment in the chemical milling groove and the milling amount A of the aluminum alloy, the sodium hydroxide consumption in the chemical milling groove can be calculated through the reaction formula of the chemical milling groove; the feeding pump on the feeding tank is turned on to add the prepared high-concentration sodium hydroxide solution to the chemical milling groove, and water is added to dilute it. When the real-time concentration monitor of the sodium hydroxide production line monitors that the sodium hydroxide in the chemical milling groove reaches the optimal content, the feeding pump is automatically turned off; before the aluminum alloy is chemically milled again, it is heated to the production temperature;

[0011] Second, the early warning system in the feed tank:

[0012] The liquid level monitor monitors the liquid level of the sodium hydroxide solution in the feeding tank. When the liquid level of the sodium hydroxide solution is lower than 1 / 3 of the tank height, the early warning system is activated, and workers or the automatic feeding system add materials to the feeding tank to mix the solution. After the sodium hydroxide solution in the feeding tank is mixed, workers make a forecast based on the remaining amount of sodium hydroxide in the storage warehouse.

[0013] Third, the trough early warning system:

[0014] After each milling of aluminum alloy, the air stirring system of the milling slot is turned on, and the aluminum ion online monitor identifies the aluminum ion concentration in the milling slot. When the concentration is higher than the ion concentration threshold, the pump is turned on to pump the waste slot liquid into the temporary storage tank;

[0015] After the aluminum-containing sludge at the bottom of the milling tank is cleaned, the high-concentration sodium hydroxide solution in the feeding tank is pumped into the milling tank, and water is added to dilute it. At the same time, the wind stirring system is turned on. When the real-time concentration monitor of the sodium hydroxide production line detects that the sodium hydroxide concentration in the milling tank is higher than the optimal content of sodium hydroxide, the feeding pump is automatically turned off;

[0016] After the chemical milling tank fluid is prepared, analysts will take samples for analysis. When the prepared solution meets the preset requirements, the chemical milling production can be resumed.

[0017] Furthermore, the monthly and annual milling volumes of aluminum alloy are measured cumulatively by a weight monitoring device and used for forecasting materials of chemicals in the production process.

[0018] Furthermore, the value of ρ is 120-195 g / L.

[0019] Furthermore, the optimal content of sodium hydroxide is 175 g / L; the concentration of the high-concentration sodium hydroxide solution is 300-330 g / L.

[0020] Furthermore, the ion concentration threshold is 75 g / L.

[0021] Furthermore, the sodium hydroxide concentration in the feed tank is adjusted to 330 g / L.

[0022] Furthermore, the feeding tank is equipped with an air stirring device to regularly stir the solution, and the solution should be stirred before each feeding.

[0023] Furthermore, the preset requirement is that the sodium hydroxide content is 170-195 g / L and the bath liquid is heated to 91-103°C.

[0024] Compared with the prior art, the present invention has the following technical features:

[0025] 1. It can maintain the concentration of the tank liquid within a reasonable range, effectively ensuring the stable quality of chemical milling parts. It can shorten the chemical milling slot reversing cycle by 1 / 3, reduce the preparation time of the sodium hydroxide solution, and speed up production efficiency.

[0026] 2. The monthly and annual milling volume of aluminum produced can be obtained through the early warning system, and then the monthly and annual consumption of sodium hydroxide can be calculated. With the development of new models, the production waiting time can be shortened by reporting in advance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the method for early warning of feeding in chemical milling of aluminum and aluminum alloys provided in an embodiment of the present invention.

[0028] Among them: 1 chemical milling groove, 2 feeding pump, 3 feeding tank, 4 extraction pump, 5 temporary storage tank. DETAILED DESCRIPTION

[0029] Combined with Figure 1 The embodiment of the present invention provides a method for warning the concentration of the chemical milling groove liquid of aluminum alloy. The method can monitor the concentration of sodium hydroxide in the chemical milling groove through the real-time concentration monitor of the sodium hydroxide production line in a non-working state, add sodium hydroxide to the groove liquid in advance, and keep the sodium hydroxide content of the groove liquid within the optimal range of the process. The aluminum ion online monitor monitors the aluminum ion concentration in the groove liquid in real time, and warns of the groove failure and predicts the material in advance.

[0030] From this, the following steps can be formulated:

[0031] It is known that the reaction formula of chemical milling slot is:

[0032] 2Al+2NaOH+6H 2 O=2Na[Al(OH) 4 ]+3H 2 ↑

[0033] The relative atomic mass of Al is 27, and the relative molecular mass of sodium hydroxide is 40. From the formula, we know that the consumption ratio of aluminum and sodium hydroxide is 27:40. Therefore, when milling 1 kg of aluminum, about 1.49 kg of sodium hydroxide is consumed.

[0034] Assume that the volume of the milling slot is 30m 3 The concentration range of chemical milling groove is 120g / L-195g / L, and the concentration of sodium hydroxide after chemical milling groove production is 175g / L; when the solution concentration drops to 150g / L, it is necessary to add material. The consumption of sodium hydroxide in this process is 750Kg, that is, the milling amount of aluminum is 500kg.

[0035] Early warning system for chemical milling slot 1:

[0036] 1) A weight monitoring device is installed on the crane to accumulate and count the daily and annual milling volume of aluminum. When the accumulated milling volume of aluminum reaches 500kg, the crane's monitoring device will start an early warning.

[0037] 2) The sodium hydroxide consumption in the solution can be calculated by the reaction formula, and the feeding pump 2 is turned on to feed the material into the milling tank 1, and water is added to dilute it. When the real-time concentration monitor of the sodium hydroxide production line monitors that the sodium hydroxide content in the milling tank 1 is 175g / L, the feeding pump 2 is automatically turned off.

[0038] 3) Since the concentration variation range is not large, there is no need to conduct production analysis. When production resumes, just heat to the production temperature.

[0039] Early warning system in feed tank 3:

[0040] 1) The liquid level is monitored by a liquid level monitor. When the liquid level of the alkali solution in the dosing tank 3 is lower than 1 / 3 of the tank height, the early warning system is activated, and workers add materials to the dosing tank 3 to prepare the solution;

[0041] 2) After the solution in the feed tank 3 is prepared, the worker makes a forecast based on the remaining amount of sodium hydroxide in the storage tank;

[0042] 3) As for the concentration of sodium hydroxide in the feed tank 3, it is known that under normal temperature conditions, the solubility of sodium hydroxide is 1 kg of water can dissolve about 0.5 kg of sodium hydroxide. Therefore, the concentration of sodium hydroxide in the feed tank 3 can be adjusted to about 330 g / L. The feed tank 3 is equipped with a wind stirring device to stir the solution regularly, and the solution should be stirred before each addition.

[0043] Tank backflow warning system:

[0044] 1) After the production shift, the wind agitator is turned on, and the aluminum ion online monitor identifies the aluminum ion concentration in the chemical milling tank. When the concentration is higher than 75g / L (process requirement), the pump 4 is turned on to pump the waste tank liquid into the temporary storage tank 5;

[0045] 2) After the aluminum-containing sludge at the bottom of the tank is cleaned, the sodium hydroxide solution in the feed tank 3 is pumped into the milling tank, and water is added to dilute it. At the same time, the wind stirring device is turned on. When the real-time concentration monitor of the sodium hydroxide production line detects that the sodium hydroxide concentration in the milling tank 1 is higher than 175g / L, the feed pump 2 is automatically turned off;

[0046] 3) After the chemical milling tank liquid is prepared, the analyst takes samples for analysis. When the sodium hydroxide content of the treated solution is 170-195g / L, the tank liquid is heated to 91-103℃ and the chemical milling production can be resumed.

Claims

1. A method for early warning of slot liquid concentration in chemical milling of aluminum alloy, characterized in that: The following steps are involved: Step 1: Design an early warning system in the milling slot: A weight monitoring device is provided on the crane used to lift the aluminum alloy into the chemical milling slot. Each time the aluminum alloy is lifted, the weight monitoring device is turned on to calculate the accumulated milling amount of the aluminum alloy; wherein the milling amount is the difference in mass of the aluminum alloy before and after entering the chemical milling slot; It is set that when the milling amount of aluminum alloy reaches the preset value A, the monitoring device of the crane starts the early warning; the calculation formula of A is: A=27*v*ρ / 40 In the above formula, v represents the volume of the chemical milling slot, and ρ is the concentration of sodium hydroxide after the chemical milling slot is produced and prepared; According to the sodium hydroxide concentration after production and deployment in the chemical milling groove and the milling amount A of the aluminum alloy, the consumption of sodium hydroxide in the chemical milling groove can be calculated through the reaction formula of the chemical milling groove; Open the feeding pump on the feeding tank to add the prepared high-concentration sodium hydroxide solution to the milling groove, and dilute it with water. When the real-time concentration monitor of the sodium hydroxide production line monitors that the sodium hydroxide content in the milling groove reaches the optimal content, the feeding pump is automatically closed; before milling the aluminum alloy again, heat it to the production temperature; Step 2: Early warning system in the feed tank: The liquid level monitor monitors the liquid level of the sodium hydroxide solution in the feeding tank. When the liquid level of the sodium hydroxide solution is lower than 1 / 3 of the tank height, the early warning system is activated, and workers or the automatic feeding system add materials to the feeding tank to mix the solution. After the sodium hydroxide solution in the feeding tank is mixed, workers make a forecast based on the remaining amount of sodium hydroxide in the storage warehouse. Step 3: Tank failure warning system: After each milling of aluminum alloy, the air stirring system of the milling slot is turned on, and the aluminum ion online monitor identifies the aluminum ion concentration in the milling slot. When the concentration is higher than the ion concentration threshold, the pump is turned on to pump the waste slot liquid into the temporary storage tank; After the aluminum-containing sludge at the bottom of the milling tank is cleaned, the high-concentration sodium hydroxide solution in the feeding tank is pumped into the milling tank, and water is added to dilute it. At the same time, the wind stirring system is turned on. When the real-time concentration monitor of the sodium hydroxide production line detects that the sodium hydroxide concentration in the milling tank is higher than the optimal content of sodium hydroxide, the feeding pump is automatically turned off; After the chemical milling tank fluid is prepared, analysts will take samples for analysis. When the prepared solution meets the preset requirements, the chemical milling production can be resumed.

2. The method for early warning of slot liquid concentration in aluminum alloy chemical milling grooves according to claim 1 is characterized in that: The monthly and annual milling volumes of aluminum alloy are measured cumulatively through the weight monitoring device and used for forecasting materials of chemicals in the production process.

3. The method for early warning of slot liquid concentration in aluminum alloy chemical milling grooves according to claim 1 is characterized in that: The value of ρ is 120~195g / L.

4. The method for early warning of slot liquid concentration in aluminum alloy chemical milling grooves according to claim 1, characterized in that: The optimal content of sodium hydroxide is 175g / L; the concentration of high-concentration sodium hydroxide solution is 300-330g / L.

5. The method for early warning of slot liquid concentration in aluminum alloy chemical milling groove according to claim 1, characterized in that: The ion concentration threshold is 75 g / L.

6. The method for early warning of slot liquid concentration in aluminum alloy chemical milling according to claim 1, characterized in that: The sodium hydroxide concentration in the feed tank is adjusted to 330 g / L.

7. The method for early warning of slot liquid concentration in aluminum alloy chemical milling grooves according to claim 1, characterized in that: The feeding tank is equipped with an air stirring device to stir the solution regularly, and the solution should be stirred before each addition.

8. The method for early warning of slot liquid concentration in aluminum alloy chemical milling grooves according to claim 1, characterized in that: The preset requirements are that the sodium hydroxide content is 170-195 g / L and the bath liquid is heated to 91-103°C.

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