Device and method for measuring content of metallic aluminum in aluminum ash

Abstract

The invention belongs to the technical field of aluminum ash detection, and discloses a device for measuring the content of metallic aluminum in aluminum ash, which comprises a nitrogen bottle, an ammonia gas absorption bottle, a double-elbow gas measuring pipe, a reaction bottle, a sample bottle, a leveling bottle, an electric furnace, a copper oxide pipe, a first gas guide pipe, a second gas guide pipe and a breather pipe, the breather pipe is provided with a first valve, a third valve, a fourth valve, a fifth valve and a sixth valve in sequence; the upper end of a spherical pipe of the double-elbow gas measuring pipe is connected with the breather pipe through a fifth valve, and the lower ends of a straight pipe and the spherical pipe of the double-elbow gas measuring pipe are connected with the leveling bottle through a seventh valve and an eighth valve respectively; one end of the copper oxide tube is connected with the third valve, and the other end of the copper oxide tube is connected with the fourth valve. Ammonia gas absorption and copper oxide reduction are achieved through valve switching, the hydrogen amount is obtained by measuring the volume, temperature and air pressure of gas in the device before and after copper oxide reduction through hydrogen, then the metal aluminum content in the aluminum ash is obtained, and the influence of aluminum nitride and aluminum carbide in the aluminum ash is effectively avoided.

Description

Technical Field

[0001] This invention belongs to the field of aluminum ash detection technology, and relates to a device and method for determining the metallic aluminum content in aluminum ash. Background Technology

[0002] Aluminum ash is a solid waste generated during the production and smelting processes of electrolytic aluminum ingot casting and aluminum processing. Based on the aluminum content and degree of treatment, aluminum ash is classified into primary aluminum ash and secondary aluminum ash. Primary aluminum ash is the ash with aluminum extraction value; it is generally grayish-white, and its main components are metallic aluminum, alumina, and some salts added during the smelting process. The aluminum content is generally 15%–50%. Secondary aluminum ash is generally grayish-black and is the residue after aluminum extraction from primary aluminum ash. Its main components are aluminum (5–20%), alumina (30–70%), salts (10–30%), and other components.

[0003] The aluminum content in aluminum ash determines its various industrial applications, making rapid and accurate detection of this content crucial. However, due to the complex composition of aluminum ash and the high reactivity of aluminum, accurate aluminum detection remains challenging. Currently, the industry primarily employs methods such as the alkaline dissolution hydrogen generation method, EDTA titration, and potassium dichromate method to measure the aluminum content in aluminum ash.

[0004] The alkaline hydrogen generation method (such as YS / T1179.2—2017) involves reacting metallic aluminum in an aluminum ash sample with sodium hydroxide to displace a corresponding amount of hydrogen gas, and then calculating the mass fraction of metallic aluminum based on the volume of hydrogen gas. However, aluminum ash contains aluminum nitride, which reacts with sodium hydroxide to generate ammonia gas, thus interfering with the determination and causing the result to be too high; aluminum ash also contains aluminum carbide, which reacts with sodium hydroxide to generate methane, thus interfering with the determination and causing the result to be too high. In addition, the instantaneous gas pressure before and after the reaction is not measured, and the gas pressure may change, causing errors.

[0005] The EDTA titration method (e.g., CN111289507A) involves dissolving the aluminum ash sample in a bromine-methanol mixture. All the metallic aluminum in the sample dissolves, while oxides such as aluminum oxide remain undissolved. Then, excess EDTA solution is added to completely complex the aluminum in the solution. The excess EDTA is then titrated with a zinc standard solution. The volume of zinc standard solution consumed in the titration is used to determine the metallic aluminum content in the aluminum ash. However, in this method, both aluminum nitride and aluminum carbide react with water, affecting the accuracy of the detection.

[0006] The potassium dichromate method (e.g., CN 118566215 A) involves reacting metallic aluminum with Fe under air-free conditions. 3+ A redox reaction occurs to produce Fe. 2+ Al2O3 does not react with Fe 3+A redox reaction occurs, and the Fe produced is titrated with potassium dichromate standard solution. 2+ The method quantitatively determines the content of metallic aluminum. However, aluminum ash contains metallic iron. When metallic aluminum is oxidized, metallic iron is also oxidized, thus interfering with the determination and causing the result to be too high. Summary of the Invention

[0007] This invention addresses the technical problem of inaccurate detection results in existing methods for determining the metallic aluminum content in aluminum ash by providing a device and method for determining the metallic aluminum content in aluminum ash. By switching valves, ammonia absorption and copper oxide reduction are achieved. The amount of hydrogen is obtained by measuring the volume, temperature, and pressure of the gas in the device before and after the reduction of copper oxide by hydrogen, and thus the metallic aluminum content in the aluminum ash is obtained, effectively avoiding the influence of aluminum nitride and aluminum carbide in the aluminum ash.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This invention provides an apparatus for determining the metallic aluminum content in aluminum ash, comprising a nitrogen cylinder, an ammonia absorption bottle, a double-elbow gas measuring tube, a reaction flask, a sample bottle, a leveling bottle, an electric furnace, a copper oxide tube, a first gas delivery tube, a second gas delivery tube, and a ventilation tube; the ventilation tube is multi-segmented and sequentially equipped with valves No. 1, No. 3, No. 4, No. 5, and No. 6, with the front end of the ventilation tube connected to the nitrogen cylinder and the rear end connected to the atmosphere; the sample bottle is placed inside the reaction flask, the mouth of which is fitted with a rubber stopper, and one end of the first gas delivery tube is inserted through the rubber stopper. The first end of the gas tube is connected to the reaction flask, and the second end is connected to the gas outlet of the reaction flask. The other end is connected to the valve. The ammonia absorption flask is equipped with valve number two at the top, and its connection with the venting pipe is located between valve number one and valve number three. The upper end of the spherical tube of the double-elbow gas measuring tube is connected to the venting pipe through valve number five. The lower ends of the straight tube and the spherical tube of the double-elbow gas measuring tube are connected to the leveling bottle through valve number seven and valve number eight, respectively. The copper oxide tube is placed inside the electric furnace, with one end connected to valve number three and the other end connected to valve number four.

[0010] In the above technical solution, the double-elbow gas measuring tube is provided with a sleeve, the sleeve is filled with water, and the thermometer is inserted into the sleeve through the end cap.

[0011] In the above technical solution, the measuring device also includes a heater and a water tank.

[0012] In the above technical solution, the first air guide tube and the second air guide tube are rubber hoses.

[0013] In the above technical solution, valves No. 2, No. 7 and No. 8 are all glass pistons, valves No. 1, No. 3, No. 4 and No. 6 are all T-type three-way valves, and valve No. 5 is an L-type three-way valve.

[0014] This invention also provides a method for determining the metallic aluminum content in aluminum ash based on the above-mentioned measuring device, comprising the following steps:

[0015] 1) Fill the ammonia absorption bottle with the absorption liquid and the leveling bottle with the sealing liquid. Assemble the measuring device, measure the initial volume of the device, and check the airtightness.

[0016] 2) Turn on the electric furnace and raise the temperature inside the furnace to 350℃. Switch the valve and move the level bottle up and down to ensure that the copper powder in the copper oxide tube 22 is completely oxidized.

[0017] 3) Add excess sodium hydroxide solution to the reaction flask and place it on the heater. Weigh aluminum ash and put it into the sample bottle. Place the sample bottle on the reaction flask and let it float on the sodium hydroxide solution. Tighten the rubber stopper of the reaction flask.

[0018] 4) When the temperature inside the electric furnace drops from 350℃ to 280℃, switch the valve and move the level bottle up and down to replace the air in the measuring device with nitrogen; switch the valve to isolate the copper oxide tube from other systems, and connect the reaction bottle, ammonia absorption bottle and double elbow measuring tube to isolate the system from the outside world.

[0019] 5) Shake the reaction flask to tilt the sample vial, allowing the reaction gas to enter the double-elbow gas measuring tube. After reacting for a period of time, turn on the heater to accelerate the reaction. After the reaction is complete, place the reaction flask in a water bath to cool it down.

[0020] 6) Switch the valve to discharge the reaction gas in the double-elbow gas measuring tube into the ammonia absorption bottle so that the ammonia is fully absorbed;

[0021] 7) Adjust the water tank temperature and the water temperature inside the sleeve to be consistent with the room temperature, read the value of the double elbow gas measuring tube, and when the value remains unchanged for two consecutive times, record the ambient pressure, ambient temperature and the value of the double elbow gas measuring tube at this time, and calculate the remaining gas pressure in the entire measuring device before hydrogen reduces copper oxide, after subtracting the water vapor pressure.

[0022] 8) Switch the valves so that the gas in the double-elbow gas measuring tube first enters the ammonia absorption bottle, and then slowly passes from the ammonia absorption bottle through the copper oxide tube until the hydrogen is completely consumed by the copper oxide. Then close all valves.

[0023] 9) Adjust the water tank temperature and the water temperature in the sleeve to match the room temperature again, read the value of the double elbow gas measuring tube, and when the value remains unchanged for two consecutive times, record the ambient pressure, ambient temperature and the value of the double elbow gas measuring tube at this time, and calculate the remaining gas pressure in the entire measuring device after hydrogen reduction of copper oxide, minus the water vapor pressure.

[0024] 10) Calculate the aluminum content in the aluminum ash based on the residual gas pressure, ambient temperature, and double-elbow gas measuring tube readings in the entire measuring device before hydrogen reduction of copper oxide, after hydrogen reduction of copper oxide, the residual gas pressure, ambient temperature, and double-elbow gas measuring tube readings in the entire measuring device, and the initial volume of the measuring device.

[0025] In the above technical solution, the formula for calculating the remaining gas pressure in the entire measuring device before hydrogen reduction of copper oxide, after subtracting the water vapor pressure, is as follows:

[0026] (Formula 1),

[0027] Where: P3 is the residual gas pressure in the entire measuring apparatus before hydrogen reduction of copper oxide, minus the water vapor pressure, in Pa; P1 is the ambient pressure before hydrogen reduction of copper oxide powder, in Pa; f is the sum of the instrument correction value, temperature correction value, and gravity correction value of the mercury barometer, in Pa; P 水 P is the saturated vapor pressure of water at 20°C, expressed in Pa. 水 =2338.8 Pa; This is a correction value for the saturated vapor pressure of water when the ambient temperature t1 differs from 20℃ by 1℃, in Pa. =145Pa.

[0028] In the above technical solution, the formula for calculating the remaining gas pressure in the entire measuring device after subtracting the water vapor pressure after hydrogen reduction of copper oxide is as follows:

[0029] (Formula 2),

[0030] Where: P4 is the residual gas pressure in the entire measuring apparatus after reducing the water vapor pressure following the reduction of copper oxide with hydrogen, in Pa; P2 is the ambient pressure after the reduction of copper oxide powder with hydrogen, in Pa; f is the sum of the instrument correction value, temperature correction value, and gravity correction value of the mercury barometer, in Pa; P 水 P is the saturated vapor pressure of water at 20°C, expressed in Pa. 水 =2338.8 Pa; This is a correction value for the saturated vapor pressure of water when the ambient temperature t2 differs from 20℃ by 1℃, in Pa. =145Pa.

[0031] In the above technical solution, the formula for calculating the aluminum content in the aluminum ash is as follows:

[0032] (Formula 3),

[0033] Where: wAl V0 represents the aluminum content in the sample, in percentage (%). V0 represents the initial volume of the measuring device, in cubic meters (m³). 3 V1 is the reading of the double-elbow gas gauging tube before hydrogen reduction of copper oxide, in meters. 3 V2 is the reading from the double-elbow gas gauging tube after the reduction of copper oxide with hydrogen, in meters. 3 P3 is the residual gas pressure in the entire measuring apparatus before hydrogen reduction of copper oxide, minus the water vapor pressure, in Pa; P4 is the residual gas pressure in the entire measuring apparatus after hydrogen reduction of copper oxide, minus the water vapor pressure, in Pa; t1 is the ambient temperature before hydrogen reduction of copper oxide, in °C; t2 is the ambient temperature after hydrogen reduction of copper oxide, in °C; m is the mass of the sample, in g; R is the gas constant; M Al This represents the molar mass of metallic aluminum, expressed in g / mol.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] This invention utilizes the reaction of sodium hydroxide solution with metallic aluminum in mill aluminum ash to generate hydrogen gas. By switching valves, ammonia absorption and copper oxide reduction are achieved. The volume, temperature, and pressure of the gas in the device before and after the reduction of copper oxide by hydrogen are measured. Based on the ideal gas equation, the difference in the amount of gas in the device before and after the reduction of copper oxide by hydrogen is calculated as the amount of hydrogen gas produced, which is then converted into the mass of metallic aluminum. The metallic aluminum content in the sample is then calculated, effectively avoiding the influence of aluminum nitride and aluminum carbide in the aluminum ash. Attached Figure Description

[0036] Figure 1 This is one of the schematic diagrams of the measuring device of the present invention.

[0037] Figure 2 This is a second schematic diagram of the measuring device of the present invention.

[0038] The following labels are used in the attached diagram: 1 is a nitrogen cylinder, 2 is an ammonia absorption bottle, 3 is a double-elbow gas measuring tube, 4 is a sleeve, 5 is a reaction flask, 6 is a sample bottle, 7 is a water tank, 8 is a heater, 9 is the first gas delivery tube, 10 is the second gas delivery tube, 11 is valve 1, 12 is valve 2, 13 is valve 3, 14 is valve 4, 15 is valve 5, 16 is valve 6, 17 is valve 7, 18 is valve 8, 19 is a thermometer, 20 is a leveling bottle, 21 is an electric furnace, 22 is a copper oxide tube, and 23 is a venting tube. Detailed Implementation

[0039] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods. The experimental instruments involved in the device of the present invention are all conventional instruments.

[0040] Example 1

[0041] like Figure 1 As shown, the measuring device of the present invention includes a nitrogen cylinder 1, an ammonia absorption bottle 2, a double-elbow gas measuring tube 3, a reaction bottle 5, a sample bottle 6, a leveling bottle 20, an electric furnace 21, a copper oxide tube 22, a first gas guide tube 9, a second gas guide tube 10, and a gas inlet tube 23.

[0042] The ventilation tube 23 consists of six horizontal glass tubes, which are connected sequentially through valve 11, valve 33, valve 44, valve 5, and valve 6. The frontmost horizontal glass tube is connected to nitrogen cylinder 1 through a flexible tube, and the rearmost horizontal glass tube is open to the atmosphere.

[0043] The ammonia absorption bottle 2 is equipped with valve 12 at its upper end, which connects to the vent pipe 23 between valve 11 and valve 13. The ammonia absorption bottle 2 contains a red absorption liquid, which is prepared by mixing 150 mL of water, 50 mL of 50% sulfuric acid solution, and 3 drops of 1 g / L methyl orange indicator. After the absorption liquid is prepared, hydrogen gas is introduced into the bottom at a flow rate of 0.5 L / min for 5 minutes before being poured into the ammonia absorption bottle 2.

[0044] The copper oxide tube 22 is placed inside the electric furnace 21, with one end connected to valve 13 and the other end connected to valve 14.

[0045] The reaction flask 5 has a rubber stopper at its mouth. One end of the first gas delivery tube 9 is inserted into the reaction flask 5 through the rubber stopper, and the other end is connected to valve 11. One end of the second gas delivery tube 10 is connected to the gas outlet of the reaction flask 5, and the other end is connected to valve 16. The reaction flask 5 contains a 100 g / L sodium hydroxide solution, and the sample bottle 6 is placed inside the reaction flask 5 during the reaction.

[0046] The upper end of the bulbous tube of the double-elbow gas measuring tube 3 is connected to the vent tube 23 via valve 15 (No. 5). The lower ends of the straight tube and bulbous tube of the double-elbow gas measuring tube 3 are connected to the level bottle 20 via valves 17 (No. 7) and 18 (No. 8), respectively. The level bottle 20 contains a red sealing solution, which is prepared by adding 10 mL of 50% sulfuric acid solution, 190 mL of 250 g / L sodium chloride solution, and 3 drops of 1 g / L methyl orange indicator. After the sealing solution is prepared, hydrogen gas is introduced into the bottom at a flow rate of 0.5 L / min for 5 minutes before being poured into the level bottle 20.

[0047] To maintain the temperature of the double-elbow gas measuring tube 3 consistent with the ambient temperature during the experiment, a sleeve 4 is installed outside the double-elbow gas measuring tube 3. The sleeve 4 is filled with water, and the thermometer 19 is inserted into the sleeve 4 through the end cap. Generally, the double-elbow gas measuring tube 3 has four bulbs with a total range of 100 mL. To increase the nitrogen storage volume of the double-elbow gas measuring tube 2, an additional bulb can be added to the 0 mL mark of the double-elbow gas measuring tube 2, while keeping the position of the 0 mL mark unchanged. The sealing liquid can be raised to the bulb above the 0 mL mark by raising the level bottle 20. The volume of this additional bulb is approximately equivalent to the volume remaining after adding sodium hydroxide solution to the vent tube 23, the first gas guide tube 9, the second gas guide tube 10, and the reaction flask 5. In this way, when the level bottle is moved up and down to drive the gas flow in the system, all the gas in the system can flow back into the double-elbow gas measuring tube 3 without leaving any dead zones.

[0048] To accelerate the reaction, the measuring apparatus also includes a heater 8, on which the reaction flask 5 is placed and heated (e.g., ...). Figure 1 (As shown); to quickly lower the reaction temperature to room temperature, the measuring device also includes a water tank 7, into which the reaction flask 5 is placed for cooling (as shown). Figure 2 (As shown).

[0049] In one embodiment, the first gas guide tube 9 and the second gas guide tube 10 are both rubber hoses; valves 12, 17, and 18 are all glass pistons; valves 11, 13, 14, and 16 are all T-type three-way valves; and valve 15 is an L-type three-way valve. The straight tube of the double-elbow gas measuring tube 3 has a measuring range of 20 mL, and the spherical tube has a measuring range of 80 mL. The electric furnace 21 has a power of 0.5 KW and a temperature control accuracy of ±0.5℃, using program control: heating to 350℃ in 18 minutes and holding for 15 minutes; cooling to 280℃ in 5 minutes and holding for 120 minutes. The holding time during heating must ensure that the copper powder in the copper oxide tube 22 is completely oxidized to copper oxide. The holding time during cooling can be estimated based on the hydrogen production and must be maintained until the experiment of hydrogen reducing copper oxide is completed. After the entire experiment, the temperature is allowed to drop naturally to room temperature.

[0050] Example 2

[0051] The method for determining the metallic aluminum content in aluminum ash based on the measuring device of Example 1 specifically includes the following steps:

[0052] S1: Fill ammonia absorption bottle 2 with absorbent liquid, fill level bottle 20 with sealing liquid, and fill sleeve 4 with water, according to... Figure 1 Assemble the measuring apparatus, measure its initial volume V0, and check its airtightness to ensure there are no leaks. The specific steps for measuring the initial volume V0 of the apparatus are as follows:

[0053] S1.1: Place sample bottle 6 into reaction flask 5, seal it with rubber stopper, and weigh it at this time, denoted as m0; then add pure water to reaction flask 5 until the rubber stopper is sealed, weigh it at this time, denoted as m1; subtract m0 from m1 to obtain the weight of pure water, divide the weight of pure water by the density of pure water at this temperature, and calculate the volume of reaction flask 5.

[0054] S1.2: Measure the inner diameter of the vent pipe 23, the first vent pipe 9, and the second vent pipe 10; measure the length of the first vent pipe 9 from the rubber stopper to valve 11; measure the length of the second vent pipe 10 from the gas outlet of reaction bottle 5 to valve 16; measure the length of the horizontal section of the vent pipe 23; and calculate the volume of each of the above pipes.

[0055] S1.3: The initial volume V0 of the measuring device is obtained by adding the volume of each pipe in the device to the volume of reaction flask 5, and then subtracting the volume of sodium hydroxide solution added to reaction flask 5 during the reaction.

[0056] S2: Turn on the electric furnace 21 and raise the furnace temperature to 350℃. Switch the valve and move the level bottle 20 up and down to ensure that the copper powder in the copper oxide tube 22 is completely oxidized. The specific operation is as follows:

[0057] Turn on the electric furnace 21 and raise the furnace temperature to 350℃ in 18 minutes, then keep it warm for 15 minutes. During the heating process, open the rubber stopper of reaction flask 5, disconnect the vent pipe 23 between valve 11 and nitrogen cylinder 1, close valve 12, open valve 11 to connect the left and right horizontal channels, open valve 3 to connect the left horizontal channel and the upper vertical channel, open valve 4 to connect the right horizontal channel and the upper vertical channel, open valve 5 to connect the left horizontal channel and the lower vertical channel, open valve 7 and valve 8, lower the leveling bottle 20, allowing air to flow at approximately 15 mL / min through valve 13 into copper oxide tube 22, and then through valve 5 into double-elbow gas measuring tube 3. Open valve 5 to connect the right horizontal channel and the lower vertical channel, open valve 6 to connect the left and right horizontal channels to connect the system with the outside, raise the leveling bottle 20 to discharge the gas in double-elbow gas measuring tube 3; open valve 5 to connect the left horizontal channel and the lower vertical channel, lower the leveling bottle 20, allowing air to flow at approximately 15 mL / min again. A flow rate of mL / min enters the copper oxide tube 22 through valve 13, and then enters the double-elbow gas metering tube 3 through valve 15. The flow rate is changed by switching valve 15 three times to connect the right horizontal channel with the lower vertical channel and the left horizontal channel with the lower vertical channel, so that the copper powder in the copper oxide tube 22 is completely oxidized.

[0058] S3: Add excess sodium hydroxide solution to reaction flask 5 and place it on heater 8. Weigh aluminum ash and put it into sample bottle 6. Float sample bottle 6 on the sodium hydroxide solution and seal the rubber stopper of reaction flask 5 tightly.

[0059] S4: When the temperature inside the electric furnace 21 drops from 350℃ to 280℃, switch the valve and move the level bottle 20 up and down to replace the air in the measuring device with nitrogen; switch the valve to isolate the copper oxide tube 22 from other systems, and connect the reaction bottle 5, ammonia absorption bottle 2, and double-elbow gas measuring tube 3 to isolate the system from the outside world. The specific operation is as follows:

[0060] S4.1: When the temperature inside the electric furnace 21 drops from 350℃ to 280℃, the vent pipe 23 connecting valve 11 and nitrogen cylinder 1 maintains the nitrogen output pressure at 2 kPa.

[0061] S4.2: Open valve 16 to connect the left and right horizontal channels, open valves 17 and 18, open valve 15 to connect the right horizontal channel and the lower vertical channel, so that the double elbow gas measuring tube 3 is connected to the outside. Raise the position of the level bottle 20 so that the sealing liquid in the double elbow gas measuring tube 3 rises to below valve 15, and the air in the double elbow gas measuring tube 3 is discharged.

[0062] S4.3: Open valve 11 to connect the left and right horizontal and lower vertical channels; open valves 17 and 18; open valve 15 to connect the left horizontal and lower vertical channels; open valve 6 to connect the left and right horizontal and lower vertical channels. Nitrogen enters the system, causing the liquid level in the double-elbow gas measuring tube 3 to drop. Open valve 15 to connect the right horizontal and lower vertical channels, venting the gas from the double-elbow gas measuring tube 3. Repeat switching valve 15 between the right horizontal and lower vertical channels and the left horizontal and lower vertical channels three times to fill the system with nitrogen, except for copper oxide tube 22.

[0063] S4.4: Open valve 13 to connect the left horizontal channel and the upper vertical channel; open valve 4 to connect the right horizontal channel and the upper vertical channel; open valve 15 to connect the left horizontal channel and the lower vertical channel. Nitrogen gas enters the copper oxide tube 22, causing the liquid level in the double-elbow gas measuring tube 3 to drop. Open valve 15 to connect the right horizontal channel and the lower vertical channel, venting the gas in the double-elbow gas measuring tube 3. Repeat switching valve 15 to connect the right horizontal channel and the lower vertical channel, and the left horizontal channel and the lower vertical channel, three times to replace the air in the copper oxide tube 22 with nitrogen gas.

[0064] S4.5: Open valve 13 (connecting the left and right horizontal channels) and valve 14 (connecting the left and right horizontal channels) to isolate copper oxide tube 22 from other systems; open valve 15 (connecting the left horizontal channel and the lower vertical channel), and open valve 12 (connecting reaction flask 5, ammonia absorption flask 2, and double-elbow gas measuring tube 3); open valve 11 (connecting the right horizontal channel and the lower vertical channel), close valve 18, and open valve 16 (connecting the left horizontal channel and the lower vertical channel) to isolate the system from the outside environment. After nitrogen purging, fill double-elbow gas measuring tube 3 with nitrogen to approximately 1 mL.

[0065] S5: Shake reaction flask 1 to tilt sample bottle 6, allowing the reaction gas to enter the double-elbow gas measuring tube 3. After reacting for a period of time, turn on heater 8 to accelerate the reaction. After the reaction is complete, place reaction flask 1 in water tank 7 to cool it down.

[0066] S6: Switch the valve to release the reaction gas in the double-elbow gas measuring tube 3 into the ammonia absorption bottle 2, so that the ammonia is fully absorbed. The specific operation is as follows:

[0067] Open valve 15 (number 5) to connect the right horizontal channel and the lower vertical channel. Open valve 18 (number 8) and valve 12 (number 2). Connect the double-elbow gas measuring tube 3 and the second gas guide tube 10. Raise the level bottle 20 to force the gas in the double-elbow gas measuring tube 3 and the second gas guide tube 10 into the reaction bottle 5 and the ammonia absorption bottle 2. Open valve 15 (number 5) to connect the left horizontal channel and the lower vertical channel. Lower the level bottle 20 to introduce the gas in the ammonia absorption bottle 2 into the double-elbow gas measuring tube 3. Repeat this operation 5 times to ensure that the ammonia in the reaction gas is fully absorbed. Then close valve 12 (number 2).

[0068] S7: Adjust the temperature of the water tank 7 and the water temperature in the sleeve 4 to be consistent with the indoor temperature. Read the value of the double elbow gas measuring tube 3 at 7-minute intervals. When the value remains unchanged for two consecutive times, record the ambient pressure P1, ambient temperature t1 and the value V1 of the double elbow gas measuring tube 3. Calculate the remaining gas pressure P3 in the entire measuring device before hydrogen reduces copper oxide by subtracting the water vapor pressure according to formula (1).

[0069] S8: Switch the valve so that the gas in the double-elbow gas measuring tube 3 first enters the ammonia absorption bottle 2, and then slowly enters the copper oxide tube 22 from the ammonia absorption bottle 2 until the hydrogen is completely consumed by the copper oxide. The specific operation is as follows:

[0070] Open valve 15 to connect the right horizontal channel and the lower vertical channel. Open valve 18 and valve 12 to connect the double-elbow gas measuring tube 3 and the second gas guide tube 10. Open valve 13 to connect the left horizontal channel and the upper vertical channel. Open valve 14 to connect the right horizontal channel and the upper vertical channel. Raise the level bottle 20 to discharge the gas in the double-elbow gas measuring tube 3 and the second gas guide tube 10 into the ammonia absorption bottle 2. Open valve 15 to connect the left horizontal channel and the lower vertical channel. Lower the level bottle 20 to allow the gas in the ammonia absorption bottle 2 to enter the copper oxide tube 22 through valve 13 at a rate of 10 mL / min, and then enter the double-elbow gas measuring tube 3 through valve 14. Read the value of the double-elbow gas measuring tube 3. Repeat the above operation. When the value remains unchanged for two consecutive times, it is determined that the hydrogen has been completely consumed by the copper oxide. Close valve 12, open valve 13 to connect the left and right horizontal channels, and open valve 14 to connect the left and right horizontal channels, thus isolating the copper oxide tube 22 from the system.

[0071] S9: Adjust the temperature of the water tank 7 and the water temperature in the sleeve 4 to be consistent with the indoor temperature. Read the value of the double elbow gas measuring tube 3. When the value remains unchanged for two consecutive times, record the ambient pressure P2, ambient temperature t2 and the value V2 of the double elbow gas measuring tube 3. Calculate the remaining gas pressure P4 in the entire measuring device after reducing the water vapor pressure after hydrogen reduction of copper oxide according to formula (2).

[0072] S10: Based on the residual gas pressure P3 after subtracting the water vapor pressure in the entire measuring device before hydrogen reduction of copper oxide, the ambient temperature t1, the reading V1 of the double-elbow gas measuring tube, the residual gas pressure after subtracting the water vapor pressure in the entire measuring device after hydrogen reduction of copper oxide, the ambient temperature t2, the reading V2 of the double-elbow gas measuring tube, and the initial volume V0 of the measuring device, calculate the metallic aluminum content w in the aluminum ash according to formula (3). Al .

[0073] The aluminum ash used in this invention is the ash that has passed through a sieve with a mesh size of less than 60 after ball milling. The amount of aluminum ash in the sample can be estimated based on the amount of metallic aluminum in the aluminum ash. If the metallic aluminum content in the aluminum ash is 0.1~2%, the weight of aluminum ash in sample bottle 6 can be 1 g; if the metallic aluminum content in the aluminum ash is 2~10%, the weight of aluminum ash in sample bottle 6 can be 0.5 g; if the metallic aluminum content in the aluminum ash is 10~25%, the weight of aluminum ash in sample bottle 6 can be 0.2 g.

[0074] In one embodiment, 50 mL of sodium hydroxide solution is added to reaction flask 1, the aluminum ash sample is m=1 g, the reaction formula is: 2Al+2NaOH+2H2O=2NaAlO2+3H2, and the reaction formula for the reduction of copper oxide by hydrogen is: CuO+H2=Cu+H2O. The measured values ​​were V0 = 35 mL, t1 = 24.5 ℃, and the sum of the correction values ​​for the mercury barometer was f = -0.1 - 3.299 - (t1 - 20) * 0.165 - 0.98 = -5.1215 hPa (hPa), P1 = 1019.6 hPa, P3 = 984.6 hPa, V1 = 50.2 mL; t2 = 24.3 ℃, and the sum of the correction values ​​for the mercury barometer was f = -0.1 - 3.299 - (t2 - 20) * 0.165 - 0.98 = -5.088 hPa, P2 = 1018.9 hPa, P4 = 984.2 hPa, V2 = 8.3 mL. The aluminum content w in the aluminum ash was then calculated. Al =3%.

[0075] In another embodiment, 50 mL of sodium hydroxide solution was added to reaction flask 1, and the aluminum ash sample was m = 1 g. The following measurements were taken: V0 = 35 mL, t1 = 22.5 ℃, the sum of correction values ​​for the mercury barometer was f = -0.1 - 3.299 - (t1 - 20) * 0.165 - 0.98 = -4.7915 hPa, P1 = 1015.7 hPa, P3 = 983.9 hPa, V1 = 50.6 mL; t2 = 23.5 ℃, the sum of correction values ​​for the mercury barometer was f = -0.1 - 3.299 - (t2 - 20) * 0.165 - 0.98 = -4.9565 hPa, P2 = 1016.3 hPa, P4 = 982.9 hPa, V2 = 8.9 mL. The aluminum content w in the aluminum ash was then calculated. Al =3.02%.

[0076] Therefore, by measuring the volume, pressure, and temperature of the gas in the apparatus before and after the reduction of copper oxide with hydrogen, and then using the ideal gas law, the amount of hydrogen used to reduce copper oxide can be obtained, and thus the amount of metallic aluminum in the sample can be determined.

[0077] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.

[0078] The embodiments described above are merely preferred embodiments of the present invention and are only used to explain the present invention. They are not intended to limit the scope of the present invention. For those skilled in the art, other implementation methods can be easily made by substitution or modification based on the technical content disclosed in this specification. Therefore, all changes and improvements made on the principle of the present invention should be included within the scope of the patent application of the present invention.

Claims

1. An apparatus for determining the metallic aluminum content in aluminum ash, characterized in that, The system includes a nitrogen cylinder (1), an ammonia absorption bottle (2), a double-elbow gas measuring tube (3), a reaction flask (5), a sample bottle (6), a leveling bottle (20), an electric furnace (21), a copper oxide tube (22), a first gas guide tube (9), a second gas guide tube (10), and a venting tube (23). The venting tube (23) is multi-segmented and sequentially equipped with valves No. 1 (11), No. 3 (13), No. 4 (14), No. 5 (15), and No. 6 (16). The front end of the venting tube (23) is connected to the nitrogen cylinder (1), and the rear end is connected to the atmosphere. The sample bottle (6) is placed inside the reaction flask (5). The mouth of the reaction flask (5) is equipped with a rubber stopper. One end of the first gas guide tube (9) is inserted into the reaction flask (5) through the rubber stopper, and the other end... The first end is connected to valve 1 (11), and the second gas guide tube (10) is connected to the gas outlet of the reaction bottle (5) at one end and to valve 6 (16) at the other end; the upper end of the ammonia absorption bottle (2) is equipped with valve 2 (12), and its connection with the gas pipe (23) is located between valve 1 (11) and valve 3 (13); the upper end of the spherical tube of the double elbow gas measuring tube (3) is connected to the gas pipe (23) through valve 5 (15), and the lower ends of the straight tube and spherical tube of the double elbow gas measuring tube (3) are connected to the level bottle (20) through valve 7 (17) and valve 8 (18) respectively; the copper oxide tube (22) is placed in the electric furnace (21), and one end is connected to valve 3 (13) and the other end is connected to valve 4 (14).

2. The measuring device according to claim 1, characterized in that, The double-elbow gas measuring tube (3) is provided with a sleeve (4), which is filled with water. The thermometer (19) passes through the end cap of the sleeve (4) and is inserted into the sleeve (4).

3. The measuring device according to claim 1, characterized in that, It also includes a heater (8) and a water tank (7).

4. The measuring device according to claim 1, characterized in that, The first air guide tube (9) and the second air guide tube (10) are rubber hoses.

5. The measuring device according to claim 1, characterized in that, The valves No. 2 (12), No. 7 (17) and No. 8 (18) are all glass pistons, the valves No. 1 (11), No. 3 (13), No. 4 (14) and No. 6 (16) are all T-type three-way valves, and the valve No. 5 (15) is an L-type three-way valve.

6. A method for determining the metallic aluminum content in aluminum ash based on the measuring apparatus according to any one of claims 1 to 5, characterized in that, Includes the following steps: 1) Fill the ammonia absorption bottle (2) with the absorption liquid, fill the level bottle (20) with the sealing liquid, assemble the measuring device, measure the initial volume of the device, and check the airtightness. 2) Turn on the electric furnace (21) and raise the temperature inside the furnace to 350°C. Switch the valve and move the level bottle (20) up and down to make the copper powder in the copper oxide tube (22) completely oxidized. 3) Add excess sodium hydroxide solution to the reaction flask (5) and place it on the heater (8). Weigh aluminum ash and put it into the sample bottle (6). Place the sample bottle (6) on the reaction flask (1) and let it float on the sodium hydroxide solution. Tighten the rubber stopper of the reaction flask (5). 4) When the temperature inside the electric furnace (21) drops from 350℃ to 280℃, switch the valve and move the level bottle (20) up and down to replace the air in the measuring device with nitrogen; switch the valve to isolate the copper oxide tube (22) from other systems, and connect the reaction bottle (5), ammonia absorption bottle (2) and double elbow gas measuring tube (3) to isolate the system from the outside world; 5) Shake the reaction flask (1) to tilt the sample bottle (6) and let the reaction gas enter the double elbow gas measuring tube (3). After the reaction has been going on for a period of time, turn on the heater 8 to accelerate the reaction. After the reaction is over, place the reaction flask (1) in the water tank (7) to cool it down. 6) Switch the valve to discharge the reaction gas in the double elbow gas measuring tube (3) into the ammonia absorption bottle (2) so that the ammonia is fully absorbed; 7) Adjust the temperature of the water tank (7) and the water temperature in the sleeve (4) to be consistent with the room temperature, read the value of the double elbow gas measuring tube (3), and when the value remains unchanged for two consecutive times, record the ambient pressure, ambient temperature and the value of the double elbow gas measuring tube (3) at this time, and calculate the remaining gas pressure in the entire measuring device before hydrogen reduces copper oxide, after subtracting the water vapor pressure. 8) Switch the valves so that the gas in the double-elbow gas measuring tube (3) first enters the ammonia absorption bottle (2), and then slowly passes through the copper oxide tube (22) until the hydrogen is completely consumed by the copper oxide. Then close all valves. 9) Adjust the temperature of the water tank (7) and the water temperature in the sleeve (4) to be consistent with the room temperature. Read the value of the double elbow gas measuring tube (3). When the value remains unchanged for two consecutive times, record the ambient pressure, ambient temperature and the value of the double elbow gas measuring tube (3) at this time. Calculate the remaining gas pressure in the entire measuring device after subtracting the water vapor pressure after hydrogen reduces copper oxide. 10) Calculate the aluminum content in the aluminum ash based on the residual gas pressure, ambient temperature, and double-elbow gas measuring tube readings in the entire measuring device before hydrogen reduction of copper oxide, after hydrogen reduction of copper oxide, the residual gas pressure, ambient temperature, and double-elbow gas measuring tube readings in the entire measuring device, and the initial volume of the measuring device.

7. The determination method according to claim 6, characterized in that, The formula for calculating the residual gas pressure in the entire measuring device before hydrogen reduction of copper oxide, after subtracting the water vapor pressure, is as follows: ， Where: P3 is the residual gas pressure in the entire measuring apparatus before hydrogen reduction of copper oxide, minus the water vapor pressure, in Pa; P1 is the ambient pressure before hydrogen reduction of copper oxide powder, in Pa; f is the sum of the instrument correction value, temperature correction value, and gravity correction value of the mercury barometer, in Pa; P 水 P is the saturated vapor pressure of water at 20°C, expressed in Pa. 水 =2338.8 Pa; This is a correction value for the saturated vapor pressure of water when the ambient temperature t1 differs from 20℃ by 1℃, in Pa. =145 Pa.

8. The determination method according to claim 6, characterized in that, The formula for calculating the remaining gas pressure in the entire measuring device after subtracting the water vapor pressure after hydrogen reduction of copper oxide is as follows: ， Where: P4 is the residual gas pressure in the entire measuring apparatus after reducing the water vapor pressure following the reduction of copper oxide with hydrogen, in Pa; P2 is the ambient pressure after the reduction of copper oxide powder with hydrogen, in Pa; f is the sum of the instrument correction value, temperature correction value, and gravity correction value of the mercury barometer, in Pa; P 水 P is the saturated vapor pressure of water at 20°C, expressed in Pa. 水 =2338.8 Pa; This is a correction value for the saturated vapor pressure of water when the ambient temperature t2 differs from 20℃ by 1℃, in Pa. =145 Pa.

9. The determination method according to claim 6, 7 or 8, characterized in that, The formula for calculating the aluminum content in the aluminum ash is as follows: ， Where: w Al V0 represents the aluminum content in the sample, in percentage (%). V0 represents the initial volume of the measuring device, in cubic meters (m³). 3 V1 is the reading of the double-elbow gas gauging tube before hydrogen reduction of copper oxide, in meters. 3 V2 is the reading from the double-elbow gas gauging tube after the reduction of copper oxide with hydrogen, in meters. 3 P3 is the residual gas pressure in the entire measuring apparatus before hydrogen reduction of copper oxide, minus the water vapor pressure, in Pa; P4 is the residual gas pressure in the entire measuring apparatus after hydrogen reduction of copper oxide, minus the water vapor pressure, in Pa; t1 is the ambient temperature before hydrogen reduction of copper oxide, in °C; t2 is the ambient temperature after hydrogen reduction of copper oxide, in °C; m is the mass of the sample, in g; R is the gas constant; M Al This represents the molar mass of metallic aluminum, expressed in g / mol.

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