Method and device for detecting corrosivity of acidic liquid

Abstract

The invention provides a method and a device for detecting the corrosivity of acidic liquid. The device for detecting the corrosivity of the acid liquid is used for implementing the method for detecting the corrosivity of the acid liquid. According to the method for detecting the corrosivity of the acid liquid, the neutralization reaction heat of the reaction between the acid liquid and the strong base is associated with the corrosivity of the acid liquid, and the corrosivity of the acid liquid is preliminarily screened according to the measured neutralization reaction heat of the reaction between the acid liquid and the strong base; and the coupon corrosion test is only carried out on the preliminarily screened acidic liquid which may have corrosivity, so that the accuracy of the preliminary screening is relatively high.

Description

Technical Field

[0001] This invention belongs to the field of corrosion detection technology, and particularly relates to a method and apparatus for detecting the corrosiveness of acidic liquids. Background Technology

[0002] With economic development, the output of hazardous chemicals and their mixtures, as well as liquid and solid waste, is increasing year by year. These substances are characterized by complex composition, numerous types, and wide range of sources and uses, making it difficult to accurately predict their physicochemical properties. Identification is necessary to determine their hazards and subsequent management methods. Corrosivity is an important category. During the production, storage, transportation, and disposal of hazardous chemicals and their mixtures, as well as liquid and solid waste, incorrect classification of corrosivity can lead to corrosion failure of production, storage, and transportation equipment and metal components used in disposal, and even accidents such as rupture of metal containers or pipelines, and collapse of metal components. Clearly defining the corrosivity of hazardous chemicals and their mixtures, as well as liquid and solid waste, is a crucial aspect of safety management.

[0003] Currently, both domestic and international standards require the use of corrosive testing with attached samples to determine the corrosivity of liquids by calculating the corrosion rate. Since this test typically takes a long time, generally seven days, pH testing is often used for initial screening to save time and costs. For weakly acidic or neutral liquids with high pH values, corrosive testing with attached samples is not necessary. Based on the principle of pH meters, the pH method is accurate for inorganic liquids, but shows significant deviations when testing organic liquids. Currently, there is no method to accurately measure the pH value of organic liquids. However, hazardous chemicals and their mixtures, liquid and solid wastes are diverse, with organic liquids making up a considerable proportion. Directly conducting long-term corrosive testing with attached samples not only prolongs the testing period but also increases costs and waste generation. Furthermore, relying on experience for screening may lead to misjudgments, incorrect classification, and even accidents. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for detecting the corrosiveness of acidic liquids. By linking the heat of neutralization of the acidic liquid to the corrosiveness of the acidic liquid, a preliminary screening of the corrosiveness of the acidic liquid is performed. For acidic liquids that are not found to be corrosive in the preliminary screening, no further corrosive testing is conducted; only acidic liquids that are preliminarily screened as potentially corrosive are subjected to corrosive testing. This overcomes the inaccuracy problem of preliminary screening using pH value methods before corrosive testing and shortens the long cycle of directly evaluating the corrosiveness of acidic liquids through corrosive testing.

[0005] To achieve the above objectives, the first aspect of the present invention provides a method for detecting the corrosiveness of acidic liquids, comprising the following steps:

[0006] Step 1. React the acidic liquid with the strong base, and determine the heat of neutralization reaction using a reference liquid;

[0007] Step 2. Based on the heat of neutralization reaction, preliminarily screen whether the acidic liquid is corrosive or not.

[0008] Optionally, in step 1, the heat of neutralization reaction is measured in a closed environment:

[0009] An equal volume of the acidic liquid was used as the reference liquid;

[0010] First, the acidic liquid and the reference liquid are heated to the same specified temperature, and then the strong base and the acidic liquid are brought into contact and reacted.

[0011] During the reaction process, the reaction system consisting of the acidic liquid and the strong base releases heat; heat is provided to the reaction system and the reference liquid respectively by heating to maintain the reaction system and the reference liquid at the same specified temperature;

[0012] Calculate the heat of neutralization reaction according to Equation I:

[0013] ΔW=dQs / dt-dQr / dt(Equation I)

[0014] Wherein, dQs / dt represents the heat provided to the reaction system per unit time;

[0015] dQr / dt represents the heat supplied to the reference liquid per unit time.

[0016] Optionally, in step 2, the corrosiveness of the acidic liquid is initially screened according to the following criteria:

[0017] When the heat of neutralization reaction is ≤5.7J, the acidic liquid is preliminarily screened to be non-corrosive;

[0018] When the heat of neutralization reaction is >5.7J, the acidic liquid is preliminarily screened as potentially corrosive.

[0019] Optionally, the method further includes:

[0020] A strip corrosion test was conducted on the acidic liquid that was initially screened as potentially corrosive.

[0021] Optionally, the corrosion test of the pad is performed at the specified temperature;

[0022] Preferably, the specified temperature is 55°C.

[0023] A second aspect of the present invention provides an apparatus for detecting the corrosiveness of acidic liquids, used to implement the method for detecting the corrosiveness of acidic liquids as described in the first aspect of the present invention; comprising:

[0024] The reference unit provides a reference location for the reference liquid;

[0025] The test unit provides a reaction site for the contact reaction between the acidic liquid and the strong alkali;

[0026] The control and calculation unit, connected to the test unit and the reference unit respectively, is used to: monitor and control the temperature of the test unit and the reference unit, obtain the technical parameters required to calculate the heat of neutralization reaction, automatically calculate the heat of neutralization reaction, and preliminarily screen whether the acidic liquid may be corrosive or not based on the heat of neutralization reaction.

[0027] Optionally, the test unit includes:

[0028] Cup body 1;

[0029] The top cover 2 is configured to seal the mouth of the cup-shaped body 1, forming a sealed space;

[0030] The testing device 3 is set in the sealed space to provide a sealed environment for the contact reaction between the acidic liquid and the strong alkali.

[0031] Optionally, the testing device 3 includes:

[0032] Bottle body 31, used to hold the acidic liquid;

[0033] The neck sleeve 32 is a hollow tube with a first annular platform 321 inside. A thin film with a certain strength is provided on the first annular platform 321 to hold the strong alkali. The first annular platform 321 divides the neck sleeve 32 into an upper part 322 and a lower part 323. The lower part 323 is configured to be threadedly connected to the bottle body 31.

[0034] The cap 33 is threaded to the upper part 322 and is configured to cooperate with the first annular platform 321 to fix the film. When subjected to external pressure, the strong alkali is released from the neck sleeve 32 into the bottle body 31 to react with the acidic liquid.

[0035] Optionally, the bottle cap 33 includes a bolt-shaped body 331, a first pressing member 332, and a first elastic member 333 for fixing the first pressing member 332; wherein,

[0036] The bolt-shaped body 331 is constructed to be longer than the upper part 322. When the bottle cap 33 is tightened with the upper part 322, the bolt-shaped body 331 abuts against the first annular platform 321 to fix the film disposed on the first annular platform 321.

[0037] Optionally, the first pressing component 332 includes a first movable plate 332-1, a first protrusion 332-2 fixed to the front side of the first movable plate 332-1, and an arrow-shaped structure 332-3 fixed to the back side of the first movable plate 332-1; wherein,

[0038] The bolt-shaped body 331 is internally configured to accommodate the first movable plate 332-1, the arrow-shaped structure 332-3, and the first elastic component 333. Within the space formed by the bolt-shaped body 331 and the plane containing the first annular platform 321, the first elastic component 333 is disposed on the first annular platform 321, contacting and pressing the first movable plate 332-1 from below to secure it. The top of the bolt-shaped body 331 also has an opening, configured to allow the first protrusion 332-2 to extend or retract from the opening, thereby driving the first movable plate 332-1 and the arrow-shaped structure 332-3 to move up and down.

[0039] Optionally, when no external pressure is applied, the first pressing member 332 is in a first state: the first protrusion 332-2 extends out from the opening, the first movable plate 332-1 is fixed under the contact compression of the first elastic member 333, and the arrow-shaped structure 332-3 is entirely located inside the bolt-shaped body 331.

[0040] When external pressure is applied, the first pressing component 332 changes from the first state to the second state: the first protrusion 332-2 retracts from the opening into the bolt-shaped body 331 under the action of external pressure, causing the first movable plate 332-1 to compress the first elastic component 333 and move downward, pushing the tip of the arrow-shaped structure 332-3 out of the bolt-shaped body 331, piercing the film, and causing the strong alkali stored on the film to fall into the bottle body 31 and react with the acidic liquid.

[0041] Optionally, the top cover 2 includes a top cover body 21, a second pressing member 22 partially located inside the top cover body 21, and a second elastic member 23 for fixing the second pressing member 22; wherein,

[0042] The top cover body 21 is configured such that the outer diameter of its lower end is the same as the inner diameter of the cup-shaped body 1, which can seal the mouth of the cup-shaped body 1 and form the sealed space.

[0043] The second pressing member 22 is configured to transmit external pressure to the first pressing member 332 when subjected to external pressure, thereby enabling the first pressing member 332 to change from the first state to the second state.

[0044] Optionally, the second pressing component 22 includes a second movable plate 221, a second protrusion 222 fixed to the front side of the second movable plate 221, and a columnar structure 223 fixed to the back side of the second movable plate 221; wherein,

[0045] The top cover body 21 is provided with a second annular platform 212 inside; the second movable plate 221 is disposed above the second annular platform 212, and the second elastic component 23 is disposed between the second movable plate 221 and the second annular platform 212 to fix the second movable plate 221 by contact and compression; the columnar structure 223 penetrates downward through the interior of the top cover body 21; the top of the top cover body 21 is also provided with an opening, which is configured to allow the second protrusion 222 to extend or retract from the opening, thereby driving the second movable plate 221 and the columnar structure 223 to move up and down; the lower end of the columnar structure 223 is configured to extend out of the top cover body 21 to contact the first protrusion 332-2 when moving downward, transmitting external pressure, causing the first protrusion 332-2 to retract into the bolt-shaped body 331, thereby triggering the first pressing component 332 to change from the first state to the second state.

[0046] Optionally, the reference unit has the same structure as the test unit; in the reference unit, the bottle body 31 is used to hold the reference liquid, and the strong alkali is not placed on the first annular platform 321.

[0047] Optionally, the control and computing unit includes:

[0048] A temperature sensing device 4 is disposed on the outer side of the bottom surface of the cup-shaped body 1 to monitor the temperature of the reaction system composed of the acidic liquid and the strong base or the reference liquid during the reaction process.

[0049] Temperature control device 5 is configured to cover the bottom and sidewalls of the cup-shaped body 1, and provides heat to the reaction system or the reference liquid by heating to control the temperature of the reaction system or the reference liquid, and maintains the reaction system or the reference liquid at the same specified temperature; temperature sensing device 4 and temperature control device 5 are both provided at the test unit and the reference unit;

[0050] Computer 6, connected to temperature sensing device 4 and temperature control device 5 respectively located at the test unit and the reference unit, is used to: acquire the temperature of the reaction system and the reference liquid; control the heating process of the reaction system and the reference liquid by the temperature control device 5; automatically calculate the heat provided to the reaction system and the reference liquid respectively; further calculate the heat of neutralization reaction; and preliminarily screen whether the acidic liquid may be corrosive or not based on the heat of neutralization reaction.

[0051] Optionally, the computer 6 contains a program that automatically calculates the heat supplied to the reaction system and the reference liquid, respectively, based on the temperatures of the reaction system and the reference liquid; and / or

[0052] The computer 6 also contains formula I, which automatically calculates the heat of neutralization reaction; and / or

[0053] The computer 6 also contains a standard for preliminary screening of the corrosiveness of the acidic liquid, and automatically performs the preliminary screening of the corrosiveness of the acidic liquid.

[0054] Preferably, the computer 6 automatically prompts that the acidic liquid is not corrosive after preliminary screening; and automatically prompts to perform the coating corrosion test for the acidic liquid that is potentially corrosive after preliminary screening.

[0055] The beneficial effects of this invention are:

[0056] To address the problems of existing technologies, such as the poor accuracy of pH value method for preliminary screening of liquid corrosivity, the long testing cycle, high experimental cost, large waste generation, and the risk of misclassification and accidents due to experience-based screening, this invention provides a method and apparatus for detecting the corrosivity of acidic liquids. The method correlates the heat of neutralization of the acidic liquid with the corrosivity of the strong alkali reaction. Based on the measured heat of neutralization, a preliminary screening of the acidic liquid's corrosivity is performed. For acidic liquids that are not preliminarily corrosive, no corrosive testing is necessary; only those that are preliminarily suspected of being corrosive are subjected to corrosive testing. Verification has shown that, compared to the existing pH method, the method for detecting the corrosiveness of acidic liquids provided by this invention has high accuracy. For example, the method provided by this invention initially screens organic rust removers as potentially corrosive, waste antifreeze containing oxalic acid as non-corrosive, and acidic seasoning oils as potentially corrosive. In contrast, the pH method initially screens organic rust removers and waste antifreeze containing oxalic acid as having low corrosive risk, while acidic seasoning oils have some corrosive risk. Verification using the plate corrosion method shows that organic rust removers are corrosive, waste antifreeze containing oxalic acid is non-corrosive, and acidic seasoning oils are corrosive. This indicates that the method provided by this invention correctly identifies the three types of acidic liquids (organic rust removers, waste antifreeze, and acidic seasoning oils) as corrosive, while the pH method misjudges the corrosiveness of organic rust removers. In practical applications, the acidic liquid to be tested is first screened for corrosivity using the method for detecting the corrosivity of acidic liquids provided by this invention. The acidic liquid to be tested is selectively subjected to a strip corrosion test, rather than directly subjecting potentially non-corrosive acidic liquids to a strip corrosion test without prior screening. This significantly shortens the testing cycle for the corrosivity of acidic liquids. Furthermore, since the method for detecting the corrosivity of acidic liquids requires only a small amount of acidic liquid (only 20 mL), the experimental cost and waste liquid production are naturally greatly reduced. In contrast, the strip corrosion method requires at least 2 L of acidic liquid and the use of metal strips and other experimental materials or reagents, resulting in higher experimental costs and waste liquid production. Moreover, this advantage of the method for detecting the corrosivity of acidic liquids becomes even more pronounced when dealing with situations requiring corrosivity testing of large quantities of various acidic liquids.The apparatus for detecting the corrosiveness of acidic liquids provided by this invention is used to implement the method for detecting the corrosiveness of acidic liquids provided by this invention. The components of the apparatus, such as the bottle cap, neck sleeve, and top cap, are structurally designed to trigger an acid-base neutralization reaction between the acidic liquid and the strong alkali under a sealed environment. Combined with a highly sensitive temperature sensor and temperature control device, and preferably a correction system embedded in a computer, the temperature of the reaction system composed of the acidic liquid and the strong alkali, as well as the reference liquid, is automatically controlled at 55°C under computer control. The heat of neutralization reaction is automatically calculated, and a preliminary screening result for the corrosiveness of the acidic liquid is automatically given based on the calculated heat of neutralization reaction. Furthermore, the apparatus provided by this invention is small in size and simple in structure, adaptable to various indoor and outdoor application scenarios for detecting the corrosiveness of acidic liquids, and suitable for widespread use in various occasions requiring acidic liquid corrosiveness detection. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the steps of a method for detecting the corrosiveness of acidic liquids provided in an embodiment of the present invention;

[0058] Figure 2 A schematic diagram of the structural composition of the device for detecting the corrosiveness of acidic liquids provided in an embodiment of the present invention;

[0059] Figure 3 This is a schematic diagram of the structure of the test unit (or reference unit) in the apparatus for detecting the corrosiveness of acidic liquids provided in an embodiment of the present invention;

[0060] Figure 4 This is a schematic diagram of the testing device in the apparatus for detecting the corrosiveness of acidic liquids provided in an embodiment of the present invention;

[0061] Figure 5 This is a schematic diagram of the bottle body in the device for detecting the corrosiveness of acidic liquids provided in an embodiment of the present invention;

[0062] Figure 6 A perspective view (left) and a top view (right) of the bottleneck sleeve in the apparatus for detecting the corrosiveness of acidic liquids provided in an embodiment of the present invention;

[0063] Figure 7 A schematic diagram of the bottle cap in the device for detecting the corrosiveness of acidic liquids provided in an embodiment of the present invention;

[0064] Figure 8 This is a schematic diagram of the bottle cap structure in the device for detecting the corrosiveness of acidic liquids provided in an embodiment of the present invention, and shows the assembly method of the bottle neck sleeve and the bottle cap, as well as the first state of the first pressing component.

[0065] Figure 9This is the second state of the first pressing component in the device for detecting the corrosiveness of acidic liquids provided in the embodiments of the present invention;

[0066] Figure 10 A schematic diagram of the top cover in the device for detecting the corrosiveness of acidic liquids provided in an embodiment of the present invention;

[0067] Figure 11 This is a schematic diagram of the top cover in the device for detecting the corrosiveness of acidic liquids provided in an embodiment of the present invention;

[0068] Figure 12-13 This is a schematic diagram of the specific structure of the test unit (or reference unit) in the apparatus for detecting the corrosiveness of acidic liquids provided in the embodiments of the present invention, and sequentially shows the overall state of the test unit (or reference unit) before and after the application of external force;

[0069] Figure 14 This is a schematic diagram of the specific structure of the device for detecting the corrosiveness of acidic liquids provided in an embodiment of the present invention, and it also shows the specific structure of the control and calculation unit.

[0070] The following are the labeling elements in the figure:

[0071] 1 represents the cup-shaped body;

[0072] 2 represents the top cover, 21 represents the top cover body, 212 represents the second annular platform, 22 represents the second pressing component, 221 represents the second movable plate, 222 represents the second protrusion, 223 represents the columnar structure, and 23 represents the second elastic component.

[0073] 3 represents the testing device, 31 represents the bottle body, 32 represents the bottle neck sleeve, 321 represents the first annular platform, 322 represents the upper part, 323 represents the lower part, 33 represents the bottle cap, 331 represents the bolt-shaped body, 332 represents the first pressing component, 332-1 represents the first movable plate, 332-2 represents the first protrusion, 332-3 represents the arrow-shaped structure, and 333 represents the first elastic component.

[0074] 4 represents a temperature sensing device;

[0075] 5 represents the temperature control device;

[0076] 6 represents computer. Detailed Implementation

[0077] To make the technical solutions and advantages of the present invention clearer, exemplary embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not an exhaustive list of all embodiments. Furthermore, the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0078] Currently, both domestic and international standards require the use of strip corrosion tests to determine the corrosivity of liquids by calculating the corrosion rate. Because strip corrosion tests are lengthy, typically lasting 7 days, pH methods are usually used for initial screening to save time and costs. For weakly acidic or neutral liquids with high pH values, strip corrosion tests are not necessary. Based on the principle of pH meters, the pH method is accurate for inorganic liquids, but shows significant deviations when testing organic liquids. Currently, there is no method to accurately measure the pH value of organic liquids. However, hazardous chemicals and their mixtures, liquid solid wastes, and other substances are diverse, with organic liquids making up a considerable proportion. Directly conducting long-term strip corrosion tests not only prolongs the testing period but also increases testing costs and waste production. Furthermore, screening based on experience may lead to misjudgments, incorrect classification, and even accidents.

[0079] To address the aforementioned deficiencies in existing methods for testing the corrosivity of liquids, this invention provides a method and apparatus for detecting the corrosivity of acidic liquids. Generally, alkaline liquids only exhibit corrosivity under harsher environments; therefore, corrosivity is mostly concentrated in acidic liquids. Thus, this invention primarily targets the detection of the corrosivity of acidic liquids. The method for detecting the corrosivity of acidic liquids provided by this invention creatively links the heat of neutralization during the acid-base neutralization reaction between an acidic liquid and a strong alkali with the corrosivity of the acidic liquid. It accurately measures the heat of neutralization during the reaction of the acidic liquid and strong alkali in a closed environment. Based on the measured heat of neutralization, the corrosivity of the acidic liquid is preliminarily screened, leading to the conclusion that the acidic liquid may or may not be corrosive. For acidic liquids initially screened as non-corrosive, no additional strip corrosion test is required. Only acidic liquids initially screened as potentially corrosive are subjected to strip corrosion tests to further determine their corrosivity. This more targeted approach saves time compared to testing non-corrosive acidic liquids, improving overall testing efficiency and shortening the testing cycle. Furthermore, this method for detecting the corrosivity of acidic liquids offers higher accuracy than existing pH methods for initial corrosion screening, preventing accidents caused by misjudgments of acidic liquid corrosivity.

[0080] The following is combined with Figure 1 The specific steps of the method for detecting the corrosiveness of acidic liquids provided by the present invention will be described in detail.

[0081] like Figure 1 As shown, the method for detecting the corrosiveness of acidic liquids provided by the present invention includes the following steps:

[0082] S1. React an acidic liquid with a strong base, and determine the heat of neutralization reaction using a reference liquid;

[0083] S2. Based on the heat of neutralization reaction, the acidic liquid is preliminarily screened to determine whether it is corrosive or not.

[0084] In some embodiments, in S1, the heat of neutralization reaction is measured in a closed environment:

[0085] An equal volume of the acidic liquid was used as the reference liquid;

[0086] First, the acidic liquid and the reference liquid are heated to the same specified temperature, and then the strong base and the acidic liquid are brought into contact and reacted.

[0087] During the reaction process, the reaction system consisting of the acidic liquid and the strong base releases heat; heat is provided to the reaction system and the reference liquid respectively by heating to maintain the reaction system and the reference liquid at the same specified temperature;

[0088] Calculate the heat of neutralization reaction according to Equation I:

[0089] ΔW=dQs / dt-dQr / dt(Equation I)

[0090] Wherein, dQs / dt represents the heat provided to the reaction system per unit time;

[0091] dQr / dt represents the heat supplied to the reference liquid per unit time.

[0092] Based on extensive research, the inventors established a correlation between the heat of neutralization reaction and the corrosivity of the acidic liquid during the acid-base neutralization reaction between acidic liquid and strong base. They also clarified a critical value for the heat of neutralization reaction that can represent whether the acidic liquid is corrosive or not. A heat of neutralization reaction higher than this critical value indicates that the acidic liquid may be corrosive, while a heat of neutralization reaction lower than this critical value indicates that the acidic liquid is not corrosive.

[0093] In some embodiments, in S2, the corrosiveness of the acidic liquid is initially screened according to the following criteria:

[0094] When the heat of neutralization reaction is ≤5.7J, the acidic liquid is preliminarily screened to be non-corrosive;

[0095] When the heat of neutralization reaction is >5.7J, the acidic liquid is preliminarily screened as potentially corrosive.

[0096] As mentioned above, current domestic and international standards require the use of a strip corrosion test to determine the corrosivity of a liquid by calculating the corrosion rate. The method for detecting the corrosivity of acidic liquids provided by this invention is based on higher accuracy and can replace the existing pH method. Before conducting the strip corrosion test, the corrosivity of the acidic liquid to be tested is preliminarily screened, avoiding the use of strip corrosion tests on acidic liquids that are not actually corrosive, and shortening the detection cycle for the corrosivity of acidic liquids.

[0097] In some embodiments, the method further includes: S3. Performing the coating corrosion test on the acidic liquid that has been preliminarily screened as potentially corrosive.

[0098] In some embodiments, the corrosion test of the coated plates is performed at the specified temperature;

[0099] Preferably, the specified temperature is 55°C.

[0100] The method for detecting the corrosivity of acidic liquids provided by this invention involves performing a strip corrosion test on the acidic liquid that has been preliminarily screened as potentially corrosive, according to the steps specified in National Standard GB 30000.17-2013, Chemical Classification and Labelling Specification Part 17: Metal Corrosives, and National Standard GB 5085.1-2007, Hazardous Waste Identification Standard, on the corrosivity identification. The specific steps of the strip corrosion test are prior art and will not be elaborated here. The temperature required for the strip corrosion test in the aforementioned national standards is 55°C. To ensure that the method for detecting the corrosivity of acidic liquids is better aligned with the strip corrosion test specified in the national standards, this invention also limits the specified temperature in the method for detecting the corrosivity of acidic liquids to 55°C.

[0101] The following is combined with Figure 2-14 The present invention provides a detailed description of the structure of the apparatus for detecting the corrosiveness of acidic liquids and the specific process of implementing the method for detecting the corrosiveness of acidic liquids provided by the present invention using the apparatus.

[0102] refer to Figure 2The basic structure shown in the invention, the device for detecting the corrosiveness of acidic liquids, includes: a reference unit, a testing unit, and a control and calculation unit; wherein, the testing unit provides a reaction site for the contact reaction between the acidic liquid and the strong alkali; the reference unit provides a reference site for the reference liquid, i.e., an environment identical to that of the testing unit; the control and calculation unit is connected to the reference unit and the testing unit respectively, and is used to monitor and control the temperature of the testing unit and the reference unit, obtain the technical parameters required for calculating the heat of neutralization reaction, and automatically calculate the heat of neutralization reaction; based on the heat of neutralization reaction, the acidic liquid is preliminarily screened to determine whether it may be corrosive or not.

[0103] In some embodiments, such as Figure 3 As shown, the test unit includes a cup-shaped body 1, a top cover 2, and a test device 3. The top cover 2 is configured to seal the mouth of the cup-shaped body 1, forming a sealed space. The test device 3 is disposed within the sealed space, providing a sealed environment for the contact reaction between the acidic liquid and the strong alkali. This sealed environment improves the accuracy of determining the heat of neutralization. The reference unit has the same structure as the test unit, including the cup-shaped body 1, the top cover 2, and the test device 3. The top cover 2 is configured to seal the mouth of the cup-shaped body 1, forming a sealed space. The test device 3 is disposed within the sealed space, providing a sealed environment for the reference liquid. This sealed environment, consistent with the sealed environment of the contact reaction between the acidic liquid and the strong alkali in the test unit, also improves the accuracy of determining the heat of neutralization.

[0104] In some embodiments, such as Figure 4-6 As shown, in the testing unit, the testing device 3 includes: a bottle body 31, a bottle neck sleeve 32, and a bottle cap 33; wherein, the bottle body 31 has threads on the outer side of its opening for holding the acidic liquid; the bottle neck sleeve 32 is a hollow tube with a first annular platform 321 inside; a thin film (e.g., weighing paper, not shown in the figure) of a certain strength is provided on the first annular platform 321 to hold the strong alkali; the first annular platform 321 divides the bottle neck sleeve 32 into an upper part 322 and a lower part 323; the lower part 323 is configured to be threadedly connected to the bottle body 31; the bottle cap 33 is threadedly connected to the upper part 322 and is configured to cooperate with the first annular platform 321 to fix the thin film, and release the strong alkali from the bottle neck sleeve 32 into the bottle body 31 when subjected to external pressure, so as to react with the acidic liquid. In the reference unit, the bottle body 31 is used to hold the reference liquid, and the strong alkali is not held on the first annular platform 321 of the testing device 3.

[0105] In some embodiments, such as Figure 7-9 As shown, in the test unit and / or the reference unit, the bottle cap 33 includes a bolt-shaped body 331, a first pressing member 332, and a first elastic member 333 for fixing the first pressing member 332; the first pressing member 332 includes a first movable plate 332-1, a first protrusion 332-2 fixed on the front side of the first movable plate 332-1, and an arrow-shaped structure 332-3 fixed on the back side of the first movable plate 332-1; wherein, the bolt-shaped body 331 is configured to have a length greater than the upper part 322, and when the bottle cap 33 is tightened with the upper part 322, the bolt-shaped body 331 abuts against the first annular platform 321 to fix the first annular platform 321. The thin film is provided on the upper part; preferably, the interior of the bolt-shaped body 331 is configured to accommodate the first movable plate 332-1, the arrow-shaped structure 332-3, and the first elastic member 333; in the space formed by the interior of the bolt-shaped body 331 and the plane where the first annular platform 321 is located, the first elastic member 333 is disposed on the first annular platform 321, and contacts and presses the first movable plate 332-1 from below to fix it; the top of the bolt-shaped body 331 is also provided with an opening, which is configured to allow the first protrusion 332-2 to extend or retract from the opening, thereby driving the first movable plate 332-1 and the arrow-shaped structure 332-3 to move up and down.

[0106] In some embodiments, when no external pressure is applied in the test unit, such as Figure 8 As shown, the first pressing component 332 is in a first state: the first protrusion 332-2 extends from the opening, the first movable plate 332-1 is fixed under the contact compression of the first elastic component 333, and the arrow-shaped structure 332-3 is entirely located inside the bolt-shaped body 331; when external pressure is applied, such as Figure 9 As shown, the first pressing component 332 transitions from the first state to the second state: under external pressure, the first protrusion 332-2 retracts from the opening into the bolt-shaped body 331 (this does not mean that the first protrusion 332-2 retracts completely into the bolt-shaped body 331; it may be that the first protrusion 332-2 partially retracts into the bolt-shaped body 331), causing the first movable plate 332-1 to compress the first elastic component 333 downwards, pushing the tip of the arrow-shaped structure 332-3 out of the bolt-shaped body 331, piercing the film, and causing the strong alkali stored on the film to fall into the bottle body 31, where it comes into contact with the acidic liquid and reacts. In the reference unit, except that the strong alkali does not contain the strong alkali and therefore does not react with the acidic liquid, the state change of the first pressing component 332 is also as described above.

[0107] In some embodiments, such as Figure 10-11 As shown, in the test unit and / or the reference unit, the top cover 2 includes a top cover body 21, a second pressing member 22 partially located inside the top cover body 21, and a second elastic member 23 for fixing the second pressing member 22; wherein, the top cover body 21 is configured such that the outer diameter of its lower end is the same as the inner diameter of the cup-shaped body 1, which can seal the mouth of the cup-shaped body 1 to form the sealed space; the second pressing member 22 is configured such that when subjected to external pressure, it can transmit the external pressure to the first pressing member 332, thereby realizing the transformation of the first pressing member 332 from the first state to the second state.

[0108] In some embodiments, such as Figure 11 As shown, in the test unit and / or the reference unit, the second pressing component 22 includes a second movable plate 221, a second protrusion 222 fixed on the front side of the second movable plate 221, and a columnar structure 223 fixed on the back side of the second movable plate 221; wherein, a second annular platform 212 is provided inside the top cover body 21; the second movable plate 221 is disposed above the second annular platform 212, and the second elastic component 23 is disposed between the second movable plate 221 and the second annular platform 212 to fix the second movable plate 221 by contact and compression; the columnar structure 223 penetrates downward through the interior of the top cover body 21; the top of the top cover body 21 is also provided with an opening, configured to allow the second protrusion 222 to extend or retract from the opening, thereby driving the second movable plate 221 and the columnar structure 223 to move up and down.

[0109] In some embodiments, such as Figure 12-13 As shown, in the test unit and / or the reference unit, the columnar structure 223 is configured such that its lower end can extend out of the top cover body 21 to contact the first protrusion 332-2 when moving downwards, transmitting external pressure to cause the first protrusion 332-2 to retract into the bolt-shaped body 331, thereby triggering the first pressing member 332 to change from the first state to the second state.

[0110] In some embodiments, in the test unit and / or the reference unit, the test unit further includes a magnetic stirring device (not shown in the figure), which is preferably disposed on the outer side of the bottom surface of the cup-shaped body 1 and cooperates with a rotor (not shown in the figure) disposed in the bottle body 31; in the test unit, the magnetic stirring device stirs the acidic liquid and the reaction system composed of the acidic liquid and the strong base during the contact reaction to ensure that the acidic liquid and the reaction system composed of the acidic liquid and the strong base are heated uniformly; in the reference unit, the magnetic stirring device stirs the reference liquid to ensure that the reference liquid is heated uniformly; the magnetic stirring device helps to improve the accuracy of the neutralization reaction heat measurement results.

[0111] In some embodiments, such as Figure 14 As shown, the control and calculation unit includes: a temperature sensing device 4, disposed on the outer side of the bottom surface of the cup-shaped body 1, for monitoring the temperature of the reaction system composed of the acidic liquid and the strong base or the reference liquid during the reaction process; a temperature control device 5, configured to cover the bottom surface and sidewalls of the cup-shaped body 1, for providing heat to the reaction system or the reference liquid by heating to control the temperature of the reaction system or the reference liquid, maintaining the reaction system or the reference liquid at the same specified temperature; both the temperature sensing device 4 and the temperature control device 5 are disposed at the test unit and the reference unit; a computer 6, connected to the temperature sensing device 4 and the temperature control device 5 disposed at the test unit and the reference unit respectively, for: acquiring the temperature of the reaction system and the reference liquid; controlling the heating process of the reaction system and the reference liquid by the temperature control device 5; automatically calculating the heat provided to the reaction system and the reference liquid respectively, and further calculating the heat of neutralization reaction; and preliminarily screening whether the acidic liquid may be corrosive or non-corrosive based on the heat of neutralization reaction.

[0112] In some embodiments, the computer 6 is embedded with a program capable of automatically calculating the heat supplied to the reaction system and the reference liquid, respectively, based on the temperatures of the reaction system and the reference liquid; and / or

[0113] The computer 6 also contains formula I, which automatically calculates the heat of neutralization reaction; and / or

[0114] The computer 6 also contains a standard for preliminary screening of the corrosiveness of the acidic liquid, and automatically performs the preliminary screening of the corrosiveness of the acidic liquid.

[0115] Preferably, the computer 6 automatically prompts that the acidic liquid is not corrosive after preliminary screening; and automatically prompts to perform the coating corrosion test for the acidic liquid that is potentially corrosive after preliminary screening.

[0116] It should be noted that although the temperature sensing device 4 is located on the outer side of the bottom surface of the cup-shaped body 1, and the temperature control device 5 covers the bottom surface and sidewalls of the cup-shaped body 1, both the temperature sensing device 4 and the temperature control device 5 have sufficiently high sensitivity and accuracy. Furthermore, the computer 6 preferably has a correction system embedded within it. After calibration using standard substances, the correction system can automatically correct the temperature data detected by the temperature sensing device 4 and the temperature control process of the temperature control device. It can also be used in conjunction with periodic calibration using standard substances to ensure the accuracy of the correction coefficient. Therefore, it is considered that the temperature sensing device 4 can monitor the temperature of the reaction system composed of the acidic liquid and the strong alkali, and the temperature of the reference liquid; and the temperature control device can maintain the reaction system composed of the acidic liquid and the strong alkali, and the reference liquid, at the specified temperature.

[0117] Using the apparatus for detecting the corrosiveness of acidic liquids provided by the present invention, and implementing the method for detecting the corrosiveness of acidic liquids provided in the above embodiments of the present invention, the process for detecting the corrosiveness of acidic liquids is as follows:

[0118] S1. React an acidic liquid with a strong base, and determine the heat of neutralization reaction using a reference liquid;

[0119] First, place a circular film (e.g., weighing paper) with the same diameter as the inner diameter of the upper part of the bottle neck sleeve on the first annular platform. Weigh a certain mass (e.g., 1g) of strong alkali (e.g., NaOH) and place it on the circular film. Screw the bottle cap into the upper part of the bottle neck sleeve, with the bolt-shaped body pressing against the first annular platform to press and fix the circular film, thus obtaining bottle cap-bottle neck sleeve assembly 1. Assemble bottle cap-bottle neck sleeve assembly 2 according to the above method. Unlike bottle cap-bottle neck sleeve assembly 1, strong alkali is not placed in the bottle neck sleeve in bottle cap-bottle neck sleeve assembly 2. Add equal volumes of acidic solution to bottle body 1 and bottle body 2 respectively, using the acidic liquid in bottle body 2 as the reference liquid. Insert drills into bottle body 1 and bottle body 2 respectively. Then screw bottle body 1 and bottle body 2 into the lower part of the bottle neck sleeve of bottle cap-bottle neck sleeve assembly 1 and 2 respectively, thus completing the assembly of the test unit and the test device in the reference unit (or the test device in the reference unit can be called the reference device).

[0120] Place the assembled test device and reference device into the cup-shaped bodies of the test unit and reference unit, respectively. Close the top cover 2 to ensure a seal on the cup opening, placing the test device and reference device in their respective enclosed spaces, ready for the neutralization reaction heat test. Activate the temperature control device (e.g., temperature controller), magnetic stirring device (e.g., magnetic stirrer), and temperature sensing device (e.g., temperature sensor) to heat the acidic liquid in the test device and reference device while stirring. When the computer displays that both the test device and reference device have reached 55°C, press the [button / button] simultaneously. The second protrusion above the top cover of the test unit and reference unit retracts into the top cover body under pressure, causing the second movable plate to squeeze the second elastic component downward, pushing the lower end of the columnar structure out of the top cover body, contacting the first protrusion to transmit the pressure brought by the pressing. After the first protrusion is subjected to external pressure, it retracts into the bolted body, causing the first movable plate to move downward, pushing the tip of the arrow-shaped structure downward to pierce the circular film, causing the strong alkali stored in the upper part of the neck sleeve in the test device of the test unit to fall into bottle No. 1 and react with the acidic liquid in bottle No. 1.

[0121] During the reaction, the reaction system consisting of acidic liquid and strong alkali releases heat. The computer-controlled temperature control device provides heat to the reaction system contained in the test device of the test unit and the reference liquid contained in the reference device of the reference unit, respectively, to control the temperature of the reaction system and the reference liquid at the same specified temperature (e.g., 55°C). At the same time, the computer obtains the temperature of the reaction system and the reference liquid from the temperature sensor, automatically calculates the heat provided by the temperature control device to the reaction system and the reference liquid during the reaction through the internally solidified program, and then automatically calculates the heat of neutralization reaction through Equation I solidified therein.

[0122] S2. Based on the heat of neutralization reaction, the acidic liquid is preliminarily screened to determine whether it may be corrosive or not.

[0123] The corrosivity of acidic liquids is initially screened according to the following criteria: if the heat of neutralization reaction is ≤5.7J, the acidic liquid is preliminarily screened as not corrosive; if the heat of neutralization reaction is >5.7J, the acidic liquid is preliminarily screened as potentially corrosive.

[0124] S3. Conduct a strip corrosion test on the acidic liquid that was initially screened as potentially corrosive.

[0125] Finally, at the specified temperature (e.g., 55°C), a strip corrosion test was conducted on the acidic liquid initially screened as potentially corrosive:

[0126] Metal sheets were selected as the hanging material, with dimensions of 50*25*2mm. The metal surface was polished with sandpaper, ultrasonically cleaned with ethanol and acetone, and the weight was recorded.

[0127] Add 2L of acidic liquid to two 3L containers. Suspend metal plates in the containers using PTFE (polytetrafluoroethylene) thread. Each test requires three metal plates, which are placed into the containers from three openings: one fully submerged, one partially submerged, and one suspended in the air. The upper edge of the fully submerged metal plate is 10mm above the liquid surface.

[0128] Place the container in a corrosion measuring instrument and heat it in a water bath to 55°C. The test period is 7 days, during which the liquid is not changed.

[0129] After completing the test, clean the metal sheet and brush the surface of the plate with a brush. Finally, clean the metal sheet with ethanol and acetone, dry it, weigh it and record the result.

[0130] Calculate the average corrosion rate of the metal sheets separately, and determine whether the acidic liquid is corrosive based on the calculation results of the average corrosion rate.

[0131] The following are three application examples of using the method and apparatus for detecting the corrosiveness of acidic liquids provided by the present invention to detect the corrosiveness of acidic liquids.

[0132] Example 1

[0133] This embodiment uses the method and apparatus provided by the present invention for detecting the corrosiveness of acidic liquids to perform corrosiveness testing on organic rust removers.

[0134] S1. React an acidic liquid with a strong base, and determine the heat of neutralization reaction using a reference liquid.

[0135] S1-1. Take a circular weighing paper with a diameter that matches the inner diameter of the upper part of the bottle neck sleeve. Place the weighing paper inside the bottle neck sleeve from the top and lay it flat on the first annular platform. Weigh 1g of NaOH and place it on the weighing paper. Screw the bottle cap into the upper part of the bottle neck sleeve, with the bolt-shaped body pressing against the first annular platform to tighten and fix the weighing paper, thus obtaining bottle cap-bottle neck sleeve assembly 1. Assemble the bottle cap-bottle neck sleeve assembly 2 according to the above method. The difference between bottle cap-bottle neck sleeve assembly 1 and bottle cap-bottle neck sleeve assembly 2 is that NaOH is not placed in the bottle neck sleeve.

[0136] S1-2. Use a pipette to accurately transfer 10 mL of organic rust remover into bottle 1 and bottle 2 respectively. Use the organic rust remover in bottle 2 as the reference liquid, and put the rotor into bottle 1 and bottle 2 respectively.

[0137] S1-3. Screw bottle body 1 and bottle body 2 into the lower part of the bottle neck sleeve of bottle cap-neck sleeve assembly 1 and 2 respectively to complete the assembly of the test device in the test unit and reference unit (or the test device in the reference unit can be called the reference device).

[0138] S1-4. Place the assembled test device and reference device into the cup-shaped bodies of the test unit and reference unit respectively, and close the top cover to ensure that the cup mouth of the cup body is sealed, so that the test device and reference device are in a closed space, ready for the neutralization reaction heat test; start the temperature controller and magnetic stirrer to heat the organic rust remover in the test device and reference device to 55°C;

[0139] S1-5. After completing the above preliminary steps, wait for the computer prompt and simultaneously press the second protrusion on the top cover of both the test unit and the reference unit. In the test unit, the second protrusion retracts into the top cover body under pressure, causing the second movable plate to squeeze the second elastic component downwards, pushing the lower end of the columnar structure out of the top cover body and contacting the first protrusion of the test device, transmitting the pressure from the press. After receiving external pressure, the first protrusion retracts into the bolt-shaped body, causing the first movable plate to move downwards, pushing the tip of the arrow-shaped structure downwards to pierce the weighing paper, allowing the N stored in the upper part of the bottleneck sleeve to... NaOH falls into bottle 1 and reacts with the organic rust remover. In the reference unit, except that no NaOH falls into bottle 2 to react with the organic rust remover, the movement is the same as in the test unit. During the reaction between the organic rust remover and NaOH in the test device, the reaction system of the organic rust remover and NaOH releases heat. The computer-controlled temperature controller heats the test device and the reference device respectively, keeping the reaction system of the organic rust remover and NaOH in bottle 1 and the organic rust remover in bottle 2 at 55°C.

[0140] S1-6. The temperature sensor continuously records the temperature of the reaction system consisting of organic rust remover and NaOH in bottle 1 and the temperature of the organic rust remover in bottle 2, and transmits the data to the computer. The computer automatically calculates the heat provided to the reaction system and the reference liquid respectively by using a program that combines the temperatures of the reaction system and the reference liquid. Combining the received temperature data, the computer calculates the heat provided to the reaction system consisting of organic rust remover and NaOH in bottle 1 and the organic rust remover in bottle 2 respectively. Furthermore, using the above formula I, which is also fixed in the computer, the computer calculates the difference in heat provided to the reaction system consisting of organic rust remover and NaOH in bottle 1 and the organic rust remover in bottle 2, which is ΔW, and is 32.6J. That is, the heat of neutralization reaction of organic rust remover and NaOH is 32.6J.

[0141] S2. Based on the heat of neutralization reaction, the acidic liquid is preliminarily screened to determine whether it may be corrosive or not.

[0142] S2-1. Based on the standard embedded therein, "when the heat of neutralization reaction is ≤5.7J, the acidic liquid is preliminarily screened as not corrosive; when the heat of neutralization reaction is >5.7J, the acidic liquid may be corrosive," the computer compares and finds that the heat of neutralization reaction of the organic rust remover and NaOH is 32.6J, which is greater than the limit of 5.7J, and gives a warning that the organic rust remover may be corrosive.

[0143] S3. Conduct a strip corrosion test on the acidic liquid that was initially screened as potentially corrosive;

[0144] S3-1. Aluminum and steel were selected as the hanging plate materials, with a size of 50*25*2mm. The metal surface was polished with sandpaper, ultrasonically cleaned with ethanol and acetone, and weighed. The weights of the aluminum plates were 5.5442g, 5.6012g, and 5.4563g, respectively, and the weights of the steel plates were 14.5375g, 14.6236g, and 14.4991g, respectively.

[0145] S3-2. Add 2L of organic rust remover to each of two 3L containers. Suspend metal plates into the containers using PTFE lines. Each test requires three metal plates, which are placed into the containers from three openings: one fully submerged, one partially submerged, and one suspended in the air. The upper edge of the fully submerged metal plate should be 10mm above the liquid surface.

[0146] S3-3. Place the container in a corrosion measuring instrument and heat it in a water bath to 55°C. The test period is 7 days, and the liquid is not changed during the test.

[0147] S3-4. After completing the test, clean the metal sheets and brush the surface of the sheets with a brush. Finally, clean the metal sheets with ethanol and acetone, dry them, and weigh them. The mass of the aluminum sheets is 4.7157g, 4.7663g, and 4.6201g, and the mass of the steel sheets is 11.6157g, 11.7263g, and 11.5701g.

[0148] S3-5. The average corrosion rate of the aluminum sheet is calculated to be 5.75 mm / a, and the average corrosion rate of the steel sheet is 6.84 mm / a. The corrosion rate of the steel sheet exceeds the limit of 6.25 mm / a for the corrosiveness of hazardous chemicals, indicating that the organic rust remover is corrosive.

[0149] Comparative Example 1

[0150] This comparative example uses the pH method to test the corrosiveness of organic rust removers.

[0151] Step 1: Calibrate the pH meter using standard buffer solutions with pH values ​​of 4.0 and 6.88. After calibration, rinse the pH meter probe surface with deionized water to remove the calibration buffer solution, and then use clean filter paper to absorb any remaining water.

[0152] Step 2: Pour the organic rust remover into three clean glass beakers. Insert a pH meter into the organic rust remover to measure the pH value. The measured pH value should remain stable for at least 1 minute. After the measurement, rinse the pH meter probe with ethanol and let it dry. Then measure the pH value of the organic rust remover in the other two beakers using the same testing method. The measured pH values ​​are 3.61, 3.61, and 3.60, with an average value of 3.61. Based on experience, the risk of corrosion is not high.

[0153] Example 2

[0154] This embodiment uses the method and apparatus provided by the present invention to detect the corrosivity of acidic liquids, and performs corrosivity testing on waste antifreeze containing oxalic acid.

[0155] S1. React an acidic liquid with a strong base, and determine the heat of neutralization reaction using a reference liquid.

[0156] S1-1. Same as S1-1 in Example 1;

[0157] S1-2. Use a pipette to accurately transfer 10 mL of waste antifreeze containing oxalic acid into bottle 1 and bottle 2 respectively. Use the organic rust remover in bottle 2 as the reference liquid, and put the rotor into bottle 1 and bottle 2 respectively.

[0158] S1-3. Same as S1-3 in Example 1;

[0159] S1-4. Place the assembled test device and reference device into the cup-shaped bodies of the test unit and reference unit respectively, and close the top cover to ensure that the cup mouth of the cup body is sealed, so that the test device and reference device are in a closed space, ready for the neutralization reaction heat test; start the temperature controller and magnetic stirrer to heat the waste antifreeze containing oxalic acid in the test device and reference device to 55°C;

[0160] S1-5. After completing the above preliminary steps, wait for the computer prompt and simultaneously press the second protrusion on the top cover of both the test unit and the reference unit. In the test unit, the second protrusion retracts into the top cover body under pressure, causing the second movable plate to squeeze the second elastic component downwards, pushing the lower end of the columnar structure out of the top cover body and contacting the first protrusion of the test device, transmitting the pressure from the press. After receiving external pressure, the first protrusion retracts into the bolt-shaped body, causing the first movable plate to move downwards, pushing the tip of the arrow-shaped structure downwards to pierce the weighing paper, causing the NaOH stored in the upper part of the neck sleeve to fall into bottle number 1. The reaction occurs when the waste antifreeze containing oxalic acid comes into contact with the test unit. In the reference unit, except that no NaOH falls into bottle 2 and reacts with the waste antifreeze containing oxalic acid, the movement is the same as in the test unit. During the reaction between the waste antifreeze containing oxalic acid and NaOH in the test device, the reaction system composed of the waste antifreeze containing oxalic acid and NaOH releases heat. The computer-controlled temperature controller heats the test device and the reference device respectively, keeping the reaction system composed of the waste antifreeze containing oxalic acid and NaOH in bottle 1 and the waste antifreeze containing oxalic acid in bottle 2 at 55°C.

[0161] S1-6. The temperature sensor continuously records the temperature of the reaction system consisting of waste antifreeze containing oxalic acid and NaOH in bottle 1 and the waste antifreeze containing oxalic acid in bottle 2, and transmits the data to the computer. The computer automatically calculates the heat provided to the reaction system and the reference liquid respectively by using a program that combines the temperatures of the reaction system and the reference liquid. Combining the received temperature data, the computer calculates the heat provided to the reaction system consisting of waste antifreeze containing oxalic acid and NaOH in bottle 1 and the waste antifreeze containing oxalic acid in bottle 2. Furthermore, using the above formula I which is also fixed in the computer, the computer calculates the difference ΔW between the heat provided to the reaction system consisting of waste antifreeze containing oxalic acid and NaOH in bottle 1 and the waste antifreeze containing oxalic acid in bottle 2, which is 1.3J. That is, the heat of neutralization reaction of waste antifreeze containing oxalic acid and NaOH is 1.3J.

[0162] S2. Based on the heat of neutralization reaction, the acidic liquid is preliminarily screened to determine whether it may be corrosive or not.

[0163] S2-1. Based on the standard embedded therein, "when the heat of neutralization reaction is ≤5.7J, the acidic liquid is preliminarily screened as not corrosive; when the heat of neutralization reaction is >5.7J, the acidic liquid may be corrosive," the computer compares and finds that the heat of neutralization reaction of the waste antifreeze containing oxalic acid and NaOH is 1.3J, which is less than the limit of 5.7J. Therefore, it gives a suggestion that the waste antifreeze containing oxalic acid is not corrosive and no corrosion test is required.

[0164] Comparative Example 2

[0165] This comparative example uses the pH method to determine the corrosiveness of waste antifreeze containing oxalic acid.

[0166] Step 1: Calibrate the pH meter using standard buffer solutions with pH values ​​of 4.0 and 6.88. After calibration, rinse the pH meter probe surface with deionized water to remove the calibration buffer solution, and then use clean filter paper to absorb any remaining water.

[0167] Step 2: Pour the waste antifreeze containing oxalic acid into three clean glass beakers. Insert a pH meter into the waste antifreeze containing oxalic acid to measure the pH value. The measured pH reading should remain stable for at least 1 minute. After measurement, rinse the pH meter probe with ethanol, let it dry, and then measure the pH value of the waste antifreeze containing oxalic acid in the other two beakers using the same method. The measured pH values ​​are 3.81, 3.81, and 3.80, with an average of 3.81. Based on experience, the risk of corrosion is not high.

[0168] Verification Example 1

[0169] The corrosivity of the waste antifreeze containing oxalic acid, the same as that in Example 2, was determined here using the plate corrosion method.

[0170] Step 1: Select No. 20 steel as the hanging plate material, with a size of 50*25*2mm. Polish the metal surface with sandpaper, perform ultrasonic cleaning with ethanol and acetone, and weigh the steel plates. The average weights of the steel plates are 14.5352g, 14.4529g, and 14.5047g, respectively.

[0171] Step 2: Add 2L of waste antifreeze containing oxalic acid to a 3L container. Use a PTFE line to suspend the metal strips in the container. Each test requires 3 steel strips, which are placed into the container from the three openings respectively: one fully submerged, one partially submerged, and one suspended in the air. The distance between the upper edge of the fully submerged metal strip and the liquid surface is 10mm.

[0172] Step 3: Place the container in a corrosion measuring instrument and heat it in a water bath to 55°C. The test period is 7 days, during which the liquid is not changed.

[0173] Step 4: After completing the test, clean the metal sheets and brush the surface of the plates clean with a brush. Finally, clean the metal sheets with ethanol and acetone, dry them, and weigh them. The mass of the steel sheets is 14.2369g, 14.1633g, and 14.1933g.

[0174] Step 5: The average corrosion rate of the steel sheet is calculated to be 0.70 mm / a. The corrosion rate of the steel sheet does not exceed the limit of 6.35 mm / a for hazardous waste corrosivity, and the waste antifreeze containing oxalic acid is not corrosive.

[0175] Example 3

[0176] This embodiment uses the method and apparatus provided by the present invention to detect the corrosivity of acidic liquids, and performs corrosivity testing on acidic seasoning oils containing citric acid, acetic acid, malic acid, etc.

[0177] S1. React an acidic liquid with a strong base, and determine the heat of neutralization reaction using a reference liquid.

[0178] S1-1. Same as S1-1 in Example 1;

[0179] S1-2. Use a pipette to accurately transfer 10 mL of acidic flavoring oil into bottle 1 and bottle 2 respectively. Use the acidic flavoring oil in bottle 2 as the reference liquid, and put the rotor into bottle 1 and bottle 2 respectively.

[0180] S1-3. Same as S1-3 in Example 1;

[0181] S1-4. Place the assembled test device and reference device into the cup-shaped bodies of the test unit and reference unit respectively, and close the top cover to ensure that the cup mouth of the cup body is sealed, so that the test device and reference device are in a closed space, ready for the neutralization reaction heat test; start the temperature controller and magnetic stirrer to heat the acidic flavoring oil in the test device and reference device to 55°C;

[0182] S1-5. After completing the above preliminary steps, wait for the computer prompt and simultaneously press the second protrusion on the top cover of both the test unit and the reference unit. In the test unit, the second protrusion retracts into the top cover body under pressure, causing the second movable plate to squeeze the second elastic component downwards, pushing the lower end of the columnar structure out of the top cover body and contacting the first protrusion of the test device, transmitting the pressure from the press. After receiving external pressure, the first protrusion retracts into the bolt-shaped body, causing the first movable plate to move downwards, pushing the tip of the arrow-shaped structure downwards to pierce the weighing paper, allowing the material stored in the upper part of the bottleneck sleeve to... NaOH falls into bottle 1 and reacts with the acidic seasoning oil. In the reference unit, except that no NaOH falls into bottle 2 to react with the acidic seasoning oil, the movement is the same as in the test unit. During the reaction between the acidic seasoning oil and NaOH in the test device, the reaction system composed of the acidic seasoning oil and NaOH releases heat. The computer-controlled temperature controller heats the test device and the reference device respectively, keeping the reaction system composed of acidic seasoning oil and NaOH in bottle 1 and the acidic seasoning oil in bottle 2 at 55°C.

[0183] S1-6. The temperature sensor continuously records the temperature of the reaction system consisting of acidic flavoring oil and NaOH in bottle 1 and the acidic flavoring oil in bottle 2, and transmits the data to the computer. The computer automatically calculates the heat provided to the reaction system and the reference liquid respectively by combining the temperature of the reaction system and the reference liquid with the received temperature data. The computer calculates the heat provided to the reaction system consisting of acidic flavoring oil and NaOH in bottle 1 and the acidic flavoring oil in bottle 2 respectively. Furthermore, by using the above formula I which is also fixed in the computer, the difference ΔW between the heat provided to the reaction system consisting of acidic flavoring oil and NaOH in bottle 1 and the acidic flavoring oil in bottle 2 is calculated to be 20.3J, that is, the heat of neutralization reaction of acidic flavoring oil and NaOH is 20.3J.

[0184] S2. Based on the heat of neutralization reaction, the acidic liquid is preliminarily screened to determine whether it may be corrosive or not.

[0185] S2-1. Based on the standard embedded therein, "when the heat of neutralization reaction is ≤5.7J, the acidic liquid is preliminarily screened as not corrosive; when the heat of neutralization reaction is >5.7J, the acidic liquid may be corrosive", the computer compares and finds that the heat of neutralization reaction of acidic seasoning oil and NaOH is 20.3J, which is greater than the limit of 5.7J, and gives a prompt that the acidic seasoning oil may be corrosive.

[0186] S3. Conduct a strip corrosion test on the acidic liquid that was initially screened as potentially corrosive;

[0187] S3-1. Aluminum and steel were selected as the hanging plate materials, with a size of 50*25*2mm. The metal surface was polished with sandpaper, ultrasonically cleaned with ethanol and acetone, and weighed. The weights of the aluminum plates were 5.4637g, 5.5103g, and 5.4753g, respectively, and the weights of the steel plates were 14.4669g, 14.5328g, and 14.5793g, respectively.

[0188] S3-2. Add 2L of acidic flavoring oil to two 3L containers respectively, and suspend metal plates in the containers using PTFE lines. Each test requires 3 metal plates, which are placed into the containers from the three openings respectively: one fully submerged, one partially submerged, and one suspended in the air. The upper edge of the fully submerged metal plate is 10mm away from the liquid surface.

[0189] S3-3. Place the container in a corrosion measuring instrument and heat it in a water bath to 55°C. The test period is 7 days, and the liquid is not changed during the test.

[0190] S3-4. After completing the test, clean the metal sheets and brush the surface of the sheets with a brush. Finally, clean the metal sheets with ethanol and acetone, dry them, and weigh them. The mass of the aluminum sheets is 4.4237g, 4.4666g, and 4.4295g, and the mass of the steel sheets is 12.6021g, 12.6357g, and 12.6533g.

[0191] S3-5. The average corrosion rate of the aluminum sheet is calculated to be 7.19 mm / a, and the average corrosion rate of the steel sheet is 4.45 mm / a. The corrosion rate of the aluminum sheet exceeds the limit of 6.25 mm / a for the corrosiveness of hazardous chemicals, indicating that the acidic seasoning oil is corrosive.

[0192] Comparative Example 3

[0193] The corrosiveness of the same acidic flavoring oil as in Example 3 was determined using the pH method in this comparative example.

[0194] Step 1: Calibrate the pH meter using standard buffer solutions with pH values ​​of 4.0 and 6.88. After calibration, rinse the pH meter probe surface with deionized water to remove the calibration buffer solution, and then use clean filter paper to absorb any remaining water.

[0195] Step 2: Pour the acidic flavoring oil into three clean glass beakers. Insert a pH meter into the acidic flavoring oil to measure the pH value. The measured pH value should remain stable for at least 1 minute. After the measurement, rinse the pH meter probe with ethanol and let it dry. Then measure the pH value of the acidic flavoring oil in the other two beakers using the same method. The measured pH values ​​are 2.72, 2.74, and 2.73, with an average value of 2.73. Based on experience, this indicates a certain risk of corrosion.

[0196] Table 1 is derived from the measurement results of the above embodiments and comparative examples.

[0197] Table 1 Comparison of Test Results

[0198]

[0199] As shown in Table 1, in Comparative Example 1, the pH value method showed that the organic rust remover had a low risk of corrosion. This is completely opposite to the conclusion that the organic rust remover was corrosive in step S3 of Example 1, indicating that the pH value method cannot accurately reflect the corrosivity of organic liquids, and the measurement results only have certain reference value. However, the method for detecting the corrosivity of acidic liquids provided by this invention was used to test the corrosivity of organic rust removers, waste antifreeze containing oxalic acid, and acidic seasoning oils. The results were verified by the coupon corrosion method and were all correct. Furthermore, the sample amount used in the test was smaller and the test time was shorter than that of the pH value method and the coupon corrosion method. This method overcomes the shortcomings of the existing technology, such as the long test cycle, high test cost, and higher waste output of the pH value method for accurately measuring the corrosivity of inorganic liquids and the direct long-term coupon corrosion test. It also avoids the potential for misjudgment and classification errors, or even accidents, that may occur when screening based on experience.

[0200] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0201] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0202] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0203] Certain terms are used throughout this application to refer to specific system components. As those skilled in the art will recognize, the same components may often be referred to by different names, and therefore this application is not intended to distinguish components that differ only in name and not in function. The terms "an embodiment" or "embodiment" used in the specification mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "embodiment" appearing throughout the specification does not necessarily refer to the same embodiment.

[0204] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

[0205] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Furthermore, various changes can be made to the subject, spirit, and scope of the invention to suit specific situations, materials, material compositions, and methods. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and / or modifications falling within the scope of the invention, and all changes and / or modifications made according to embodiments of the invention should be covered within the protection scope of the invention.

Claims

1. A method for detecting the corrosiveness of acidic liquids, characterized in that, Includes the following steps: Step 1. React the acidic liquid with the strong base, and determine the heat of neutralization reaction using a reference liquid; Step 2. Based on the heat of neutralization reaction, preliminarily screen whether the acidic liquid is corrosive or not.

2. The method according to claim 1, characterized in that, In step 1, the heat of neutralization reaction is measured in a closed environment: An equal volume of the acidic liquid was used as the reference liquid; First, the acidic liquid and the reference liquid are heated to the same specified temperature, and then the strong base and the acidic liquid are brought into contact and reacted. During the reaction process, the reaction system consisting of the acidic liquid and the strong base releases heat; heat is provided to the reaction system and the reference liquid respectively by heating to maintain the reaction system and the reference liquid at the same specified temperature; Calculate the heat of neutralization reaction according to Equation I: ΔW=dQs / dt-dQr / dt(Equation I) where dQs / dt represents the heat provided to the reaction system per unit time; dQr / dt represents the heat supplied to the reference liquid per unit time.

3. The method according to claim 1 or 2, characterized in that, In step 2, the corrosiveness of the acidic liquid is initially screened according to the following criteria: When the heat of neutralization reaction is ≤5.7J, the acidic liquid is preliminarily screened to be non-corrosive; When the heat of neutralization reaction is >5.7J, the acidic liquid is preliminarily screened as potentially corrosive.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: A strip corrosion test was conducted on the acidic liquid that was initially screened as potentially corrosive.

5. The method according to any one of claims 2 to 4, characterized in that, The corrosion test of the coated plate was performed at the specified temperature. Preferably, the specified temperature is 55°C.

6. An apparatus for detecting the corrosiveness of acidic liquids, characterized in that, A method for detecting the corrosiveness of acidic liquids as described in any one of claims 1 to 5; comprising: The reference unit provides a reference location for the reference liquid; The test unit provides a reaction site for the contact reaction between the acidic liquid and the strong alkali; The control and calculation unit, connected to the test unit and the reference unit respectively, is used to: monitor and control the temperature of the test unit and the reference unit, obtain the technical parameters required to calculate the heat of neutralization reaction, automatically calculate the heat of neutralization reaction, and preliminarily screen whether the acidic liquid may be corrosive or not based on the heat of neutralization reaction.

7. The apparatus according to claim 6, characterized in that, The test unit includes: cup-shaped body(1); The top cover (2) is configured to seal the mouth of the cup-shaped body (1) to form a sealed space; The test device (3) is set in the sealed space to provide a sealed environment for the contact reaction between the acidic liquid and the strong alkali.

8. The apparatus according to claim 7, characterized in that, The testing device (3) includes: Bottle body (31), used to hold the acidic liquid; The neck sleeve (32) is hollow and has a first annular platform (321) inside. A thin film with a certain strength is provided on the first annular platform (321) to hold the strong alkali. The first annular platform (321) divides the neck sleeve (32) into an upper part (322) and a lower part (323). The lower part (323) is configured to be threadedly connected to the bottle body (31). The cap (33) is threaded to the upper part (322) and is configured to cooperate with the first annular platform (321) to fix the film. When subjected to external pressure, the strong alkali is released from the neck sleeve (32) into the bottle body (31) to react with the acidic liquid.

9. The apparatus according to claim 8, characterized in that, The bottle cap (33) includes a bolt-shaped body (331), a first pressing component (332), and a first elastic component (333) for fixing the first pressing component (332); wherein, The bolt-shaped body (331) is configured to be longer than the upper part (322). When the bottle cap (33) is tightened with the upper part (322), the bolt-shaped body (331) abuts against the first annular platform (321) to fix the film disposed on the first annular platform (321).

10. The apparatus according to claim 9, characterized in that, The first pressing component (332) includes a first movable plate (332-1), a first protrusion (332-2) fixed to the front side of the first movable plate (332-1), and an arrow-shaped structure (332-3) fixed to the back side of the first movable plate (332-1); wherein, The bolt-shaped body (331) is internally configured to accommodate the first movable plate (332-1), the arrow-shaped structure (332-3), and the first elastic component (333). In the space formed by the bolt-shaped body (331) and the plane containing the first annular platform (321), the first elastic component (333) is disposed on the first annular platform (321) and contacts and presses the first movable plate (332-1) from below to fix it. The top of the bolt-shaped body (331) is also provided with an opening, which is configured to allow the first protrusion (332-2) to extend or retract from the opening, thereby driving the first movable plate (332-1) and the arrow-shaped structure (332-3) to move up and down.

11. The apparatus according to claim 10, characterized in that, When no external pressure is applied, the first pressing component (332) is in the first state: the first protrusion (332-2) extends out from the opening, the first movable plate (332-1) is fixed under the contact compression of the first elastic component (333), and the arrow-shaped structure (332-3) is entirely located inside the bolt-shaped body (331); When external pressure is applied, the first pressing component (332) changes from the first state to the second state: the first protrusion (332-2) retracts from the opening into the bolt-shaped body (331) under the action of external pressure, causing the first movable plate (332-1) to compress the first elastic component (333) to move downward, pushing the tip of the arrow-shaped structure (332-3) out of the bolt-shaped body (331), piercing the film, and causing the strong alkali stored on the film to fall into the bottle body (31) and react with the acidic liquid.

12. The apparatus according to claim 11, characterized in that, The top cover (2) includes a top cover body (21), a second pressing component (22) partially located inside the top cover body (21), and a second elastic component (23) for fixing the second pressing component (22); wherein, The top cover body (21) is configured such that the outer diameter of its lower end is the same as the inner diameter of the cup-shaped body (1), which can seal the mouth of the cup-shaped body (1) to form the sealed space. The second pressing member (22) is configured to transmit external pressure to the first pressing member (332) when subjected to external pressure, thereby enabling the first pressing member (332) to change from the first state to the second state.

13. The apparatus according to claim 12, characterized in that, The second pressing component (22) includes a second movable plate (221), a second protrusion (222) fixed to the front side of the second movable plate (221), and a columnar structure (223) fixed to the back side of the second movable plate (221); wherein, The top cover body (21) is provided with a second annular platform (212) inside; the second movable plate (221) is disposed above the second annular platform (212), and the second elastic member (23) is disposed between the second movable plate (221) and the second annular platform (212) to fix the second movable plate (221) by contact and compression; the columnar structure (223) extends downward through the interior of the top cover body (21); the top of the top cover body (21) is also provided with an opening, which is configured to allow the contents of the top cover to be inserted into the top cover. The second protrusion (222) extends or retracts from the opening, causing the second movable plate (221) and the columnar structure (223) to move up and down; the columnar structure (223) is configured such that its lower end can extend out of the top cover body (21) to contact the first protrusion (332-2) when moving downward, transmitting external pressure, causing the first protrusion (332-2) to retract into the bolt-shaped body (331), thereby triggering the first pressing component (332) to change from the first state to the second state.

14. The apparatus according to any one of claims 7 to 13, characterized in that, The reference unit has the same structure as the test unit; in the reference unit, the bottle body (31) is used to hold the reference liquid, and the strong alkali is not placed on the first annular platform (321).

15. The apparatus according to claim 14, characterized in that, The control and computing unit includes: A temperature sensing device (4) is disposed on the outer side of the bottom surface of the cup-shaped body (1) to monitor the temperature of the reaction system composed of the acidic liquid and the strong base or the reference liquid during the reaction process. The temperature control device (5) is configured to cover the bottom and sidewalls of the cup-shaped body (1) and provides heat to the reaction system or the reference liquid by heating to control the temperature of the reaction system or the reference liquid and maintain the reaction system or the reference liquid at the same specified temperature; the temperature sensing device (4) and the temperature control device (5) are both provided at the test unit and the reference unit; A computer (6) is connected to the temperature sensing device (4) and the temperature control device (5) respectively located at the test unit and the reference unit, and is used to: acquire the temperature of the reaction system and the reference liquid; control the heating process of the reaction system and the reference liquid by the temperature control device (5); automatically calculate the heat provided to the reaction system and the reference liquid respectively, and further calculate the heat of neutralization reaction; and preliminarily screen the acidic liquid based on the heat of neutralization reaction to determine whether it may be corrosive or not.

16. The apparatus according to claim 15, characterized in that, The computer (6) contains a program that automatically calculates the heat supplied to the reaction system and the reference liquid, respectively, based on the temperatures of the reaction system and the reference liquid; and / or The computer (6) also contains formula I, which automatically calculates the heat of neutralization reaction; and / or The computer (6) also contains a standard for preliminary screening of the corrosiveness of the acidic liquid, and automatically performs the preliminary screening of the corrosiveness of the acidic liquid. Preferably, the computer (6) automatically prompts that the acidic liquid is not corrosive when it is initially screened as non-corrosive; and automatically prompts to perform the coating corrosion test when it is initially screened as potentially corrosive.

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