A method for rapidly detecting iron content in noble metal in molten state

Abstract

The application belongs to the technical field of metal materials, and specifically discloses a method for rapidly detecting iron content in a noble metal in a molten state, wherein a ventilation pipeline is connected to the top of an induction melting furnace to collect the gas emitted by the induction furnace, one end of the ventilation pipeline is inserted into the liquid surface of an absorption liquid in a gas absorption chamber of an iron flue gas absorption device through a gas pipe, the absorption liquid in the gas absorption chamber is used to absorb Fe ions in the gas emitted by the induction melting furnace, a collection liquid is obtained, the collection liquid is detected by using iron test paper, the color of the test paper is recorded, the actual iron content in the molten noble metal is detected by using an ICP method, a corresponding relationship between the color of the test paper and the actual iron content in the molten noble metal detected by using the ICP method is established, a standard colorimetric card is established, the colorimetric card is used to qualitatively and semi-quantitatively and rapidly judge the iron content in the noble metal in the molten state, and the ventilation time of the noble metal purified by using a high-temperature chlorination method is rapidly judged, and the method is simple and reliable.

Description

Technical Field

[0001] This invention belongs to the field of metallic materials technology, and specifically discloses a method for rapidly detecting iron content in the molten state of precious metals. Background Technology

[0002] Document CN 112126790 A discloses a method for chlorination purification of platinum, platinum-rhodium, or platinum-rhodium-palladium alloys. This method purifies precious metals through high-temperature chlorination: platinum, platinum-rhodium, or platinum-rhodium-palladium metals are melted, and chlorine gas is passed through the molten liquid. The chlorine gas reacts with the base metal at high temperature to form chlorides. The low saturated vapor pressure of the chlorides is then used to remove the base metals. Excess chlorine gas and low-melting-point chlorides volatilize and escape. In this method, it is crucial to quickly determine whether the base metal impurity content in the precious metal meets the requirements. If the chlorination time is insufficient, the purity of the precious metal will be insufficient, requiring secondary purification. If the chlorination time is excessive, it will increase the loss of precious metals and auxiliary materials, leading to increased losses. Commonly used methods for detecting impurities in precious metals include inductively coupled plasma atomic emission spectrometry (ICP) and full-spectrum AC / DC arc emission spectrometry. The former requires chemical preparation of the solution and has a long testing cycle, while the latter cannot determine the base metal content in precious metals in the molten state of the precious metal. It can only be tested after the precious metal has been cooled, which requires specialized testing equipment and has a long testing cycle. Neither of these methods can meet the requirement of rapidly determining the base metal impurity content in the high-temperature chlorination method for purifying precious metals. Summary of the Invention

[0003] To address the problems in the background art, this invention discloses a method for rapidly detecting iron content in the molten state of precious metals. The method utilizes an iron flue gas absorption device to absorb Fe ions in the gas escaping from the smelting furnace, establishes a standard colorimetric card, and rapidly determines the Fe content in the molten metal and the gas flow time for high-temperature chlorination purification of precious metals. The method is simple and reliable.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0005] A method for rapidly detecting iron content in a molten state of precious metals, the method using an iron flue gas absorption device, the iron flue gas absorption device including a sealed gas absorption chamber, the upper end of the gas absorption chamber being connected to a storage tank via a conduit, the lower end of the gas absorption chamber being connected to a collection bottle via a conduit, valves being respectively installed on the conduit, and an air inlet and an air outlet being spaced apart on the gas absorption chamber.

[0006] The rapid method for detecting iron content includes the following steps:

[0007] 1) Establish a standard colorimetric card: Place the precious metal into an induction melting furnace and maintain it in a molten state. Pass chlorine gas above the molten metal surface. Connect a ventilation duct above the induction melting furnace to collect the gas escaping from the furnace. Insert the other end of the ventilation duct into the gas absorption chamber below the surface of the absorbent liquid. After t minutes, remove a small amount of molten metal from the induction melting furnace. After the sample cools, determine the Fe content in the sample using ICP. Simultaneously, place the absorbent liquid that captures Fe ions from the gas in the gas absorption chamber into a collection bottle. Immerse iron test paper in the collection liquid in the collection bottle, remove it, and record the color of the test paper. The collection bottle was emptied and cleaned; absorbent liquid was injected into the gas absorption chamber, and the other end of the ventilation pipe was inserted into the absorbent liquid in the gas absorption chamber through the gas tube. After t minutes, a small amount of molten liquid was taken out from the induction melting furnace. After the sample cooled, the Fe content in the sample was determined by ICP method. At the same time, the absorbent liquid that captured Fe ions in the gas in the gas absorption chamber was put into the collection bottle, and iron test paper was immersed in the collection liquid in the collection bottle. The paper was then removed and its color was recorded. This process was repeated several times to establish a correspondence between the color of the test paper and the iron content value in the sample determined by ICP method, and a standard colorimetric card was obtained.

[0008] 2) Determine the Fe content in the molten metal in the smelting furnace using a standard colorimetric card: When it is necessary to test the Fe content in the molten metal of the smelting furnace, add absorbent liquid to the gas absorption chamber, insert the other end of the ventilation pipe into the absorbent liquid in the gas absorption chamber through the gas pipe, and after t minutes, put the absorbent liquid that captures Fe ions in the gas in the gas absorption chamber into the collection bottle, immerse iron test paper in the collection liquid in the collection bottle, take it out, record the color of the test paper, compare it with the color in the standard colorimetric card, and determine the range of Fe content in the molten metal of the smelting furnace. When the Fe content reaches the requirement, stop the chlorine gas supply, and cast and cool the precious metal.

[0009] Furthermore, in the method for rapidly detecting iron content in the molten state of precious metals, t is equal to 30-60 minutes.

[0010] Furthermore, in the method for rapidly detecting iron content in the molten state of precious metals, the absorbent is deionized water.

[0011] Furthermore, the method for rapidly detecting iron content in the molten state of precious metals includes a feed inlet at the top of the storage tank.

[0012] Furthermore, the method for rapidly detecting iron content in the molten state of precious metals includes a discharge port at the bottom of the collection bottle.

[0013] Compared with the prior art, the beneficial effects of the present invention are:

[0014] This invention discloses a method for rapidly determining the iron content of precious metals in the molten state. A ventilation duct is connected above an induction melting furnace to collect the gas escaping from the furnace. The other end of the ventilation duct is inserted into the gas absorption chamber of an iron flue gas absorption device, below the liquid surface of the absorbent liquid. The absorbent liquid in the gas absorption chamber absorbs Fe ions from the gas escaping from the induction melting furnace, resulting in a collected liquid. Iron test paper is used to detect the collected liquid, and the color of the test paper is recorded. Simultaneously, the actual iron content in the molten precious metal is detected using ICP (Inductively Coupled Phosphorus) method. A correspondence is established between the test paper color and the iron content value determined by the ICP method, resulting in a standard colorimetric card. This standard colorimetric card is used to qualitatively and semi-quantitatively determine the iron content in the molten precious metal. Furthermore, it allows for rapid determination of the ventilation time during high-temperature chlorination purification of precious metals. The method is simple and reliable. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the iron flue gas absorption device in this invention;

[0016] Figure 2 This is the standard colorimetric card in this invention;

[0017] In the diagram above: 1-Storage tank; 2-Valve A; 3-Gas outlet; 4-Gas absorption chamber; 5-Liquid level line; 6-Valve B; 7-Collection bottle; 8-Gas inlet. Detailed Implementation

[0018] The present invention will be explained in detail through the following embodiments. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention.

[0019] Combined with appendix Figure 1 This invention provides a method for rapidly detecting iron content in a molten state of precious metals. The method utilizes an iron flue gas absorption device, which includes a sealed gas absorption chamber 4. The upper end of the gas absorption chamber 4 is connected to a storage tank 1 via a conduit, and the lower end of the gas absorption chamber 4 is connected to a collection bottle 7 via a conduit. A valve A2 is installed on the conduit between the gas absorption chamber 4 and the storage tank 1, and a valve B6 is installed on the conduit between the gas absorption chamber 4 and the collection bottle 7. An air inlet 8 and an air outlet 3 are also provided at intervals on the gas absorption chamber 4. Preferably, an inlet is provided at the top of the storage tank 1, and an outlet is provided at the bottom of the collection bottle 7.

[0020] The rapid method for detecting iron content includes the following steps:

[0021] Establish a standard colorimetric card: Add a precious metal with an Fe content of 0.03% to an induction melting furnace and maintain it in a molten state. Pass chlorine gas above the molten metal surface. Connect a ventilation duct above the induction melting furnace to collect the gas escaping from the furnace. Open valve A2 and inject the absorbent liquid from storage tank 1 into gas absorption chamber 4. The liquid level in gas absorption chamber 4 should not be lower than the liquid level line 5. The other end of the ventilation duct passes through the air inlet 8 and is inserted below the absorbent liquid level line 5 in gas absorption chamber 4. The absorbent liquid in gas absorption chamber 4 is deionized water. After 30 minutes, remove a small amount of molten metal from the induction melting furnace. After the sample cools, determine the Fe content in the sample using ICP. Simultaneously, open valve B6 and transfer all the absorbent liquid in gas absorption chamber 4, which has captured Fe ions from the gas, into a collection bottle. Immerse iron test paper in collection bottle 7. Immerse the iron test paper in the collection liquid for two seconds, remove it, gently shake off excess water, and record the color of the test paper. Empty the collection bottle 7, clean it thoroughly, and set it aside for future use to avoid affecting the next test results. Inject new absorption liquid into the gas absorption chamber 4 again. Insert the other end of the ventilation pipe through the air inlet 8 into the gas absorption chamber 4 below the liquid level line 5 of the absorption liquid. After 30 minutes, remove a small amount of molten metal from the induction melting furnace. After the sample cools, determine the Fe content in the sample using ICP. At the same time as sampling, place the absorption liquid that captures Fe ions in the gas in the gas absorption chamber 4 into the collection bottle 7. Immerse the iron test paper in the collection liquid in the collection bottle 7, remove it after two seconds, gently shake off excess water, and record the color of the test paper. Repeat this process several times to establish a correspondence between the color development of the iron test paper and the value of the iron content in the precious metal molten metal determined by ICP, and obtain a standard colorimetric card, such as... Figure 2 As shown;

[0022] It should be noted that the collection time is the period from when Fe ions are captured in the gas in the gas absorption chamber 4 until the Fe ion absorption liquid in the gas absorption chamber 4 is placed into the collection bottle 7. Generally, the collection time t is selected between 30 and 60 minutes. If the time is too short, the absorption liquid will have a short time to absorb Fe ions, resulting in a low Fe ion concentration in the absorption liquid and reducing the accuracy of detection. If the time is too long, the purpose of rapid judgment cannot be achieved. At the end of the collection time, a sample is taken from the induction melting furnace and the Fe content in the sample is determined by ICP method. The collection time for sample testing is the same as the collection time for establishing the colorimetric card. The collected liquid is tested with iron test paper, and the color of the obtained iron test paper is compared with the colorimetric card. The color that is closer to the color on the colorimetric card indicates that the iron content in the precious metal melt is close to the iron content corresponding to that color on the colorimetric card. The iron content in the sample is determined qualitatively and semi-quantitatively.

[0023] To determine the Fe content in the molten metal in the smelting furnace using a standard colorimetric card: When it is necessary to test the Fe content in the molten metal of the smelting furnace, add absorbent liquid to the gas absorption chamber 4, insert the other end of the ventilation pipe into the gas absorption chamber through the air inlet 8 below the liquid surface of the absorbent liquid, and after 30 minutes, put the absorbent liquid that captures Fe ions in the gas in the gas absorption chamber into the collection bottle, immerse iron test paper in the collection liquid in the collection bottle 7, take it out, record the color of the test paper, compare it with the color in the standard colorimetric card, and qualitatively and semi-quantitatively determine the iron content of the sample in the induction smelting furnace. When the Fe content reaches the requirement, stop the chlorine gas supply, and cast and cool the precious metal.

[0024] It should be noted that, in order to improve the accuracy of the test, when using the standard colorimetric card to determine the Fe content in the molten metal of the induction melting furnace, the collection time of Fe ions in the gas in the gas absorption chamber should be consistent with the collection time of Fe ions in the gas in the gas absorption chamber when establishing the standard colorimetric card. As needed, the collection time t should be selected between 30 and 60 minutes.

[0025] Example 1

[0026] A precious metal with an Fe content of 0.10% was added to an induction melting furnace. The furnace was turned on to melt the precious metal ingot. The power of the equipment was adjusted to maintain the precious metal in a molten state. A ventilation duct was connected above the furnace to collect the gas escaping from the furnace. Chlorine gas was introduced onto the surface of the molten precious metal. After 60 minutes of chlorine gas introduction, absorbent liquid was added to the iron flue gas absorption device. The absorbent liquid level was controlled at the liquid level line. After 30 minutes, the absorbent liquid that had captured Fe ions from the gas in the gas absorption chamber was placed into a collection bottle. Iron test paper was then immersed in the collection liquid in the collection bottle for 2 seconds, removed, and excess water was gently shaken off. The color of the test paper was recorded and compared with the color in the standard colorimetric card to determine that the Fe content of the sample in the induction melting furnace was 0.0045-0.0062%. After 90 minutes of chlorine gas introduction, the Fe content in the molten precious metal was determined to be 0.0049% by ICP method. The Fe content value of the sample in the induction melting furnace was determined to be close to the value determined by ICP method by colorimetric card.

[0027] Example 2

[0028] A precious metal with an Fe content of 0.18% was added to an induction melting furnace. The furnace was turned on to melt the precious metal ingot. The power of the equipment was adjusted to maintain the precious metal in a molten state. A ventilation duct was connected above the induction melting furnace to collect the gas escaping from the furnace. Chlorine gas was introduced onto the surface of the molten precious metal for 60 minutes. Absorbent liquid was added to the iron flue gas absorption device, and the liquid level was controlled at the level line. After 30 minutes, the absorbent liquid that had captured Fe ions from the gas in the gas absorption chamber was placed into a collection bottle. Iron test paper was then immersed in the collection liquid in the collection bottle for two seconds, removed, and excess water was gently shaken off. The color of the test paper was recorded and compared with the color in the standard colorimetric card to determine that the Fe content of the sample in the induction melting furnace was 0.0062-0.0087%. After 90 minutes of chlorine gas introduction, the Fe content in the molten precious metal was determined to be 0.0078% by ICP method. The Fe content value of the sample in the induction melting furnace was determined to be close to the value determined by ICP method by colorimetric card.

[0029] Example 3

[0030] A precious metal with an Fe content of 0.18% was added to an induction melting furnace. The furnace was turned on to melt the precious metal ingot. The power of the equipment was adjusted to maintain the precious metal in a molten state. A ventilation duct was connected above the induction melting furnace to collect the gas escaping from the furnace. Chlorine gas was introduced onto the surface of the molten precious metal for 90 minutes. Absorbent liquid was added to the iron flue gas absorption device, and the liquid level was controlled at the liquid level line. After 30 minutes, the absorbent liquid that had captured Fe ions from the gas in the gas absorption chamber was placed into a collection bottle. Then, iron test paper was immersed in the collection liquid in the collection bottle for two seconds, removed, and excess water was gently shaken off. The color of the test paper was recorded and compared with the color in the standard colorimetric card to determine that the Fe ion content was 0.0045-0.0062%. After 120 minutes of chlorine gas introduction, the Fe content in the molten precious metal was determined to be 0.0058% by ICP method. The Fe content value of the sample in the induction melting furnace was judged to be close to the value determined by ICP method by colorimetric card.

[0031] Example 4

[0032] Unlike Example 1, the absorption time for Fe ions in the gas in the gas absorption chamber was 15 minutes. Then, iron test paper was immersed in the collection liquid, removed after two seconds, and excess water was gently shaken off. The color of the test paper was recorded and compared with the color in the standard colorimetric card to determine that the Fe ion content was 0.0035-0.0045%. After 75 minutes of chlorine gas passage, the Fe content in the raw material was 0.0091% by ICP method. Due to the short collection time, the Fe content value of the sample in the induction melting furnace determined by the colorimetric card and the value determined by the ICP method had a large deviation.

[0033] The above description is only an application embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and cannot be used to limit the scope of the rights of the present invention. Any equivalent changes made according to the technical solution of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for rapidly determining iron content in a molten state of a precious metal, characterized in that: The rapid method for detecting iron content uses an iron flue gas absorption device, which includes a sealed gas absorption chamber. The upper end of the gas absorption chamber is connected to a storage tank via a conduit, and the lower end of the gas absorption chamber is connected to a collection bottle via a conduit. Valves are installed on the conduit, and an air inlet and an air outlet are also provided at intervals on the gas absorption chamber. The rapid method for detecting iron content includes the following steps: 1) Establish a standard colorimetric card: Place the precious metal into an induction melting furnace and maintain it in a molten state. Pass chlorine gas above the molten metal surface. Connect a ventilation duct above the induction melting furnace to collect the gas escaping from the furnace. Insert the other end of the ventilation duct into the gas absorption chamber below the surface of the absorbent liquid. After t minutes, remove a small amount of molten metal from the induction melting furnace. After the sample cools, determine the Fe content in the sample using ICP. Simultaneously, place the absorbent liquid that captures Fe ions from the gas in the gas absorption chamber into a collection bottle. Immerse iron test paper in the collection bottle. Take the sample out of the collection bottle, record the color of the test paper, and empty and clean the collection bottle. Inject the absorbent into the gas absorption chamber, and insert the other end of the ventilation pipe into the liquid surface of the absorbent in the gas absorption chamber through the gas tube. After t minutes, take out a small amount of molten liquid from the induction melting furnace. After the sample cools, determine the Fe content in the sample by ICP method. At the same time, put the absorbent that captures Fe ions in the gas in the gas absorption chamber into the collection bottle, immerse the iron test paper in the collection liquid in the collection bottle, take it out, record the color of the test paper, repeat several times to obtain the standard colorimetric card. 2) Determining the Fe content in the molten metal using a standard colorimetric card: When it is necessary to test the Fe content in the molten metal, add absorbent liquid to the gas absorption chamber. Insert the other end of the ventilation pipe into the absorbent liquid in the gas absorption chamber through the gas pipe. After t minutes, put the absorbent liquid that captures Fe ions in the gas in the gas absorption chamber into the collection bottle. Immerse iron test paper in the collection liquid in the collection bottle, take it out, record the color of the test paper, and compare it with the color in the standard colorimetric card to determine the range of Fe content in the molten metal. When the Fe content reaches the required level, stop the chlorine gas supply, and cast and cool the precious metal.

2. The method for rapid determination of iron content in the molten state of precious metals according to claim 1, characterized in that: t equals 30-60 minutes.

3. The method for rapid determination of iron content in the molten state of precious metals according to claim 1, characterized in that: The absorption solution is deionized water.

4. The method for rapid determination of iron content in the molten state of precious metals according to claim 1, characterized in that: A discharge port is provided at the bottom of the collection bottle.

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