A sample preparation method for studying blast furnace tuyere coke using a scanning electron microscope

Abstract

This invention discloses a sample preparation method for studying blast furnace tuyere coke using scanning electron microscopy. During blast furnace shutdown, tuyere coke samples and corresponding inlet coke samples from the target blast furnace are collected simultaneously. The inlet coke is prepared by cutting it into small cubic pieces, followed by resin vacuum impregnation, curing, grinding, and polishing. The tuyere coke samples are divided into two sub-samples: untreated surface samples and internally polished samples. The untreated surface samples are prepared into small cubic pieces, and their observation surfaces are left untreated to maintain their original morphology from the reaction within the blast furnace. The internally polished samples are prepared by cutting them into small cubic pieces, followed by resin vacuum impregnation, curing, grinding, and polishing. After conductivity treatment, the prepared samples are observed under a field emission scanning electron microscope to analyze their microstructure and composition. This invention has clear steps, good reproducibility, and is easily applicable to different blast furnaces and research institutions.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical engineering and ironmaking raw material analysis technology, and particularly relates to a sample preparation method for studying blast furnace tuyeres coke using scanning electron microscopy. Background Technology

[0002] The stable operation of a blast furnace depends on a precise understanding of its complex internal physicochemical processes. Traditional furnace condition assessments primarily rely on trend analysis of macroscopic parameters such as pressure, temperature, and flow rate, as well as observing the macroscopic movement and color of coke through the tuyeres. While these methods can reflect the overall situation, they are lagging and fail to reveal the deeper mechanisms underlying furnace condition fluctuations, such as the nature of coke deterioration and the interaction between slag and iron formation and coke.

[0003] Tubular coke, as the only directly visible solid material inside the blast furnace hearth, carries rich reaction information from the high-temperature zone in the lower part of the blast furnace (the swirling zone and dripping zone). Its macroscopic properties (such as brightness and activity) ultimately stem from changes in its microscopic attributes. Currently, research on tubular coke largely relies on simple observations of simulated coke in the laboratory or occasional sampling, lacking a systematic and standardized microscopic analysis process, and even more so, the development of an online diagnostic method that directly and quantitatively correlates microscopic characteristics with real-time blast furnace operation and condition.

[0004] Scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS) can provide high-resolution morphological images of material surfaces at magnifications of tens to tens of thousands of times, and can perform micro-area elemental composition analysis, making it a powerful tool for studying the microstructure of coke. Therefore, there is an urgent need for a method that can correlate the microstructure and composition of tuyeres coke observed by SEM-EDS with the blast furnace conditions. Summary of the Invention

[0005] In order to overcome the shortcomings of existing blast furnace tuyere coke research technology, the purpose of this invention is to provide a sample preparation method for studying blast furnace tuyere coke using scanning electron microscopy.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] This invention discloses a sample preparation method for studying blast furnace tuyeres coke using scanning electron microscopy, comprising:

[0008] (1) During the blast furnace shutdown period, collect coke samples from the tuyeres of the target blast furnace and their corresponding coke samples fed into the furnace simultaneously;

[0009] (2) The coke in (1) is sampled, cut into small cubes, and then subjected to resin vacuum impregnation, curing, grinding and polishing.

[0010] (3) The blast coke samples in (1) are divided into two sub-samples: untreated surface samples and internally polished samples;

[0011] (4) The untreated sample in (3) is made into a small cube, and its observation surface is left untreated to maintain its original morphology in the blast furnace reaction.

[0012] (5) Prepare the internal polished sample in (3), cut it into small cubic pieces, and perform resin vacuum impregnation, curing, grinding and polishing treatment;

[0013] (6) After the prepared sample is subjected to conductivity treatment, it is placed under a field emission scanning electron microscope for observation, and its microstructure and composition are analyzed.

[0014] Furthermore, the cubic piece has a size of (0.4-0.6) cm × (0.4-0.6) cm × (0.4-0.6) cm.

[0015] Furthermore, the cubic piece has a size of 0.5×0.5cm×0.5cm.

[0016] Furthermore, the original adhering substances are retained in the char sample from the air outlet in (3).

[0017] Furthermore, the cross-section of the internal polished sample was observed, the distribution of different phases was analyzed using backscattered electron mode, and the composition of the pore walls and specific internal regions was analyzed.

[0018] Furthermore, the method has clear steps and good reproducibility.

[0019] Furthermore, this method is easy to promote and apply across different blast furnaces and research institutions.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0021] This invention provides a standardized method for sampling, sample preparation and observation. The method has clear steps, good reproducibility and is easy to promote and apply in different blast furnaces and research institutions. Detailed Implementation

[0022] A standardized method for preparing vent coke samples for scanning electron microscopy observation, specifically including:

[0023] (1) During the blast furnace shutdown period, collect coke samples from the tuyeres of the target blast furnace and their corresponding coke samples fed into the furnace simultaneously.

[0024] (2) Prepare samples of the coke from (1), cut them into small cubes of 0.5cm×0.5cm×0.5cm, and then perform resin vacuum impregnation, curing, grinding and polishing.

[0025] (3) The blast coke samples in (1) are divided into two sub-samples: untreated surface samples (preserving the original attachments) and polished internal samples (for observing the internal structure).

[0026] (4) The untreated sample from (3) is made into a cube of 0.5cm×0.5cm×0.5cm, and its observation surface is left untreated to maintain its original morphology as it reacts in the blast furnace.

[0027] (5) Prepare the internal polished sample in (3), cut it into small cubes of 0.5cm×0.5cm×0.5cm, and then perform resin vacuum impregnation, curing, grinding and polishing.

[0028] (6) After the prepared sample is subjected to conductivity treatment, it is placed under a field emission scanning electron microscope for observation, and its microstructure and composition are analyzed.

[0029] The technical solution of the present invention will be described in detail below with reference to the embodiments.

[0030] This invention selects both tuyeres coke and furnace feed coke from Baotou Steel as the uniform coke. The sample preparation method consists of three steps:

[0031] (1) First, prepare untreated coke by cutting small pieces with original morphology from the coke block at the tuyere, cleaning and drying them for later use;

[0032] (2) Preparation of internal polished sample: The coke block at the vent is cut open along the middle, and the cross-section sample is subjected to resin vacuum impregnation, curing, grinding and polishing to obtain a flat observation surface;

[0033] (3) Preparation of furnace coke comparison samples: The furnace coke was subjected to the same embedding and polishing treatment as in step (2). After the above sample preparation was completed, it was subjected to conductivity treatment and placed under a scanning electron microscope. First, the morphology of the untreated sample was observed from low to high magnification, and the composition of typical surface deposits was analyzed. Then, the cross-section of the polished sample was observed, and the distribution of different phases was analyzed using backscattered electron mode, and the composition of the pore walls and specific internal regions was analyzed. Finally, the furnace coke comparison samples were observed, and their original microstructure characteristics were recorded as a reference.

[0034] As can be seen, this invention provides a technical approach for observing blast coke using scanning electron microscopy by standardizing the blast coke sample preparation method.

[0035] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a sample for studying blast furnace tuyere coke using a scanning electron microscope, characterized by, include: (1) During the blast furnace shutdown period, collect coke samples from the tuyeres of the target blast furnace and their corresponding coke samples fed into the furnace simultaneously; (2) Prepare samples of the coke from (1), cut them into small cubic pieces, and then perform resin vacuum impregnation, curing, grinding and polishing. (3) The blast coke samples in (1) are divided into two sub-samples: untreated surface samples and internally polished samples; (4) The untreated sample in (3) is made into a small cube, and its observation surface is left untreated to maintain its original morphology in the blast furnace reaction. (5) Prepare the internal polished sample in (3), cut it into small cubic pieces, and perform resin vacuum impregnation, curing, grinding and polishing treatment; (6) After the prepared sample is subjected to conductivity treatment, it is placed under a field emission scanning electron microscope for observation, and its microstructure and composition are analyzed.

2. The sample preparation method for studying blast furnace tuyere coke using a scanning electron microscope as claimed in claim 1, wherein, The cubic piece has dimensions of (0.4-0.6) cm × (0.4-0.6) cm × (0.4-0.6) cm.

3. A method for preparing a sample of blast furnace tuyere coke for investigation using a scanning electron microscope according to claim 1 or 2, characterized in that, The cube-shaped piece has dimensions of 0.5×0.5cm×0.5cm.

4. The sample preparation method for studying blast furnace tuyere coke using a scanning electron microscope as claimed in claim 1, wherein, The original attachments were retained in the char sample from the air outlet in (3).

5. The method for preparing a sample of blast furnace tuyere coke for investigation using a scanning electron microscope as claimed in claim 1, wherein, The cross-section of the internal polished sample was observed, and the distribution of different phases was analyzed using backscattered electron mode. The composition of the pore walls and specific internal regions was also analyzed.

6. The sample preparation method for studying blast furnace tuyere coke using scanning electron microscope as claimed in claim 1 wherein, The method has clear steps and good reproducibility.

7. The method for preparing a sample of blast furnace tuyere coke for investigation using a scanning electron microscope as claimed in claim 1, wherein, This method is easy to promote and apply across different blast furnaces and research institutions.