Method for preparing iron alloy sample through pre-oxidation melting

Abstract

The invention discloses a method for preparing an iron alloy sample by pre-oxidation melting, which comprises the following steps of: 1) filling a crucible with high-purity graphite, compacting, and making pits in the high-purity graphite; 2) uniformly mixing an oxidizing agent, a flux and a sample, adding the mixture into the pit, and oxidizing and melting under a high-temperature condition; 3) after melting and cooling, taking out the obtained glass frit; and 4) putting the taken glass frit into a platinum crucible for melting. The method can solve the problem that the platinum crucible is corroded when the glass fuse piece is prepared through high-temperature melting when the X-ray fluorescence spectrophotometer for preparing the glass sheet through melting is used for measuring all elements in the iron alloy.

Description

Technical Field

[0001] The invention belongs to the technical field of analysis, and specifically relates to a method for preparing an iron alloy sample by pre-oxidation melting, and in particular to a method for pre-oxidation melting of an iron alloy sample for determining various elements in the iron alloy by an X-fluorescence spectrometer. Background Art

[0002] The use of X-fluorescence spectrometer to determine the elements in ferroalloys has always been an important application field of X-fluorescence spectrometers. At present, the preparation of samples by the tableting method is quick and simple, but due to the influence of mineral effect and particle size effect, the accuracy of the detection is reduced. Ferroalloys are relatively expensive raw materials in the metallurgical industry. The content of each element in the ferroalloy determines the settlement price of the ferroalloy. Therefore, the application scope of the tableting method to determine the content of each element in the ferroalloy is limited. At present, the use of melting to prepare glass sheets and the use of X-fluorescence spectrometers to determine each element can well eliminate the mineral effect and particle size effect. However, since ferroalloys have strong reducibility when melted, it will cause corrosion of platinum crucibles. Therefore, how to melt and prepare ferroalloy samples well has become a difficult problem for X-fluorescence spectrometers to test the elements in ferroalloys. At present, there have been a lot of studies, among which the technology of using flux to hang on the wall and then pre-melt has begun to be promoted and applied. However, the wall hanging operation in this technology is more difficult. Summary of the invention

[0003] The purpose of the present invention is to solve the problem of corrosion of platinum crucibles when preparing glass flakes by melting and preparing glass flakes by X-ray fluorescence spectrometer. The present invention uses graphite as a reaction outer lining to mix and melt an oxidant and an iron alloy under high temperature conditions, thereby oxidizing each element in the iron alloy to form oxides, and the platinum crucible will no longer be corroded when the platinum crucible is subsequently used for melting and preparing glass flakes.

[0004] The principle of the present invention is as follows: in order to prevent the ferroalloy from corroding the platinum crucible when the sample is melted, the ferroalloy sample is pre-oxidized and melted in a corundum crucible filled with graphite. Since the corundum crucible and the sample are separated by graphite and the two are not in contact, the flux will not adhere to the crucible wall and cannot be separated. The molten block formed after the sample is melted is on the graphite, and the graphite is relatively loose, so the molten block is very easy to take out. After the sample is oxidized, it is completely converted into oxides, and the platinum crucible is no longer corroded when it is melted at a high temperature. In addition, the sample is synchronously operated without loss during the whole process, thereby ensuring the accuracy of the sample test.

[0005] Specifically, the present invention provides a method for preparing an iron alloy sample by pre-oxidation melting, which comprises the following steps:

[0006] 1) Filling a crucible with high-purity graphite, and making pits in the high-purity graphite after compaction;

[0007] 2) mixing an oxidant, a flux and a sample, adding the mixture into the pit, and oxidizing and melting the mixture under high temperature conditions;

[0008] 3) After melting and cooling, taking out the obtained glass frit;

[0009] 4) Place the taken out glass frit in a platinum crucible for melting.

[0010] In some embodiments, in step 1), the crucible is a corundum crucible with a volume of 50-80 mL.

[0011] In some embodiments, in step 1), the high-purity graphite is graphite with a carbon content of >99.99%, an ash content of <0.1%, and a particle size of <8 μm.

[0012] In some embodiments, in step 3), graphite on the surface of the glass frit is also removed.

[0013] In some embodiments, removing the graphite on the surface of the glass frit is to brush off the graphite on the surface of the glass frit with a brush.

[0014] In some embodiments, in step 4), a flux for melting the iron alloy sample is placed in the platinum crucible.

[0015] Advantages of the present invention:

[0016] 1. Graphite is used as the reaction lining to separate the sample from the corundum crucible, which prevents the sample frit from coming into contact with the crucible and being unable to be peeled off, thus making the test impossible.

[0017] 2. Use high temperature resistant corundum crucible as reaction container, which is not easy to be damaged during the reaction process and can be reused many times.

[0018] 3. High-purity graphite is used as the reaction lining. High-purity graphite will be oxidized into carbon dioxide under high temperature conditions and escape. The impurity content is very low. The remaining impurities do not affect the detection of the sample, and volatilize relatively slowly under high temperature conditions, which can ensure that the sample and the crucible are separated during the melting process.

[0019] 4. The sample molten block floats above the graphite. After high-temperature melting, the molten block is easy to take out. The sample oxidation melting process is in an open system, which can ensure the adequacy of oxidation and also ensure the safety and completeness of the oxidation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the pre-oxidation device.

[0021] Figure 2 This is a photo of the appearance of a corundum crucible.

[0022] Figure 3 A schematic diagram of the structure of a tool for compacting high-purity graphite filled in a crucible.

[0023] Figure 4 This is a photo of a tool used to compact the high-purity graphite filled in a crucible.

[0024] Figure 5 This is a photo of the graphite pits in the prepared corundum crucible.

[0025] Figure 6 This is a photo of the oxidant, flux and sample being mixed and then added to the pit.

[0026] Figure 7 This is a photograph of oxidation melting under high temperature conditions in a furnace.

[0027] Figure 8 This is a photograph of the frit present in the pit after oxidation melting.

[0028] Fig. 9 This is a photo of the glass frit obtained after melting and cooling. DETAILED DESCRIPTION

[0029] The present invention aims to provide a method for preparing an ferroalloy sample by pre-oxidation melting, which adopts Figure 1 The pre-oxidation device shown in the figure includes a corundum crucible as a shell, and the volume can be 50-80mL, such as Figure 2 As shown in the figure, it is a photo of the appearance of the corundum crucible. The crucible is filled with high-purity graphite (carbon content>99.9%, ash content<0.1%, particle size<8μm), and after compaction, it is used as follows Figure 3 The tools shown ( Figure 4 The tool is used to make a pit (a thin graphite layer can be formed between the tool and the crucible wall during the compaction process, and a smooth pit surface can be formed inside the crucible). The tool is taken out while rotating. If there is scattered graphite on the surface, it can be gently blown out. Figure 5 As shown, a photo of graphite pits in the prepared corundum crucible is shown, and then Figure 6 As shown, the oxidant, flux and sample are mixed and added to the pit, and then Figure 7 As shown, it is put into a furnace and oxidized and melted under high temperature conditions to obtain Figure 8 After the glass frit is melted and cooled, it is taken out with tweezers and the graphite on the surface is brushed off with a brush to obtain the following: Fig. 9 The molten block shown in the figure can be melted in a platinum crucible filled with a mixed flux (mixed flux used to melt the ferroalloy sample).

[0030] The present invention adopts Figure 1The pre-oxidation device shown in the figure performs pre-oxidation melting to prepare ferroalloy samples, which can ensure that the reaction vessel wall is not contacted during the melting process, and high-purity graphite is used as the reaction outer lining. The carbon dioxide formed by the graphite during the melting process will not enter the sample melt. Due to the high purity, impurity elements will not be introduced to contaminate the sample. The melt and graphite do not adhere to each other and are easy to separate. The completely oxidized melt will not corrode the platinum crucible when it is melted at high temperature in a platinum crucible to prepare a glass melt. This solves the problem of corrosion of the platinum crucible when the X-ray fluorescence spectrometer is used to measure the ferroalloy melt to prepare the sample, and opens up new ideas for the use of X-ray fluorescence spectrometers to measure the elements in ferroalloys. It has broad promotion prospects and strong practical value.

[0031] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an iron alloy sample by pre-oxidation melting, comprising the following steps: 1) Filling a crucible with high-purity graphite, and making pits in the high-purity graphite after compaction; 2) mixing an oxidant, a flux and a sample, adding the mixture into the pit, and oxidizing and melting the mixture under high temperature conditions; 3) After melting and cooling, taking out the obtained glass frit; 4) Place the taken out glass frit in a platinum crucible for melting.

2. The method according to claim 1, wherein in step 1), the crucible is a corundum crucible with a volume of 50-80 mL.

3. The method according to claim 1 or 2, wherein in step 1), the high-purity graphite is graphite with a carbon content of >99.99%, an ash content of <0.1%, and a particle size of <8 μm.

4. The method according to any one of claims 1 to 3, wherein in step 3), graphite on the surface of the glass frit is also removed.

5. The method according to claim 4, wherein removing the graphite on the surface of the glass frit is to brush off the graphite on the surface of the glass frit with a brush.

6. The method according to any one of claims 1 to 5, wherein in step 4), a flux for melting the ferroalloy sample is placed in the platinum crucible.

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