阅读说明：本技术 热分析-红外联用检测煤系高岭岩及煅烧产品碳含量的方法 (Method for detecting carbon content of coal-series kaolinite rock and calcined product by thermal analysis-infrared combined method ) 是由 李辉 成思萌 于 2020-05-26 设计创作，主要内容包括：本发明公开了一种热红联用分析煤系高岭岩及煅烧产品中碳含量的方法,具体为对已知碳含量的标准样品进行热分析-红外联用测试,得到包含波数、吸光度和时间三个坐标轴的三维红外吸收光谱图,选取CO<Sub>2</Sub>气体产生红外吸收最大的时间点,解析出对应的CO<Sub>2</Sub>气体二维红外吸收光谱图,提取碳含量对应的最大吸收强度数据,再对不同含碳量的标准样品重复上述操作,得到一系列的“碳含量-最大吸收强度”数据,以“吸收强度”为横坐标、“碳含量”为纵坐标绘制曲线图,并对曲线进行拟合,得到“吸收强度-碳含量”的标准曲线函数式,再对待测样品进行测试,并解析出CO<Sub>2</Sub>最大吸收强度的数据,带入标准曲线函数式,计算得到样品中的碳含量。(The invention discloses a method for analyzing carbon content in coal-series kaolinite rock and calcined products by thermal red coupling, which specifically comprises the steps of carrying out thermal analysis-infrared coupling test on a standard sample with known carbon content to obtain a three-dimensional infrared absorption spectrogram containing three coordinate axes of wave number, absorbance and time, selecting CO 2 Resolving corresponding CO at the time point of maximum infrared absorption of gas 2 Extracting a maximum absorption intensity data corresponding to carbon content from a gas two-dimensional infrared absorption spectrogram, repeating the operation on standard samples with different carbon contents to obtain a series of data of carbon content-maximum absorption intensity, drawing a curve graph by taking the absorption intensity as a horizontal coordinate and the carbon content as a vertical coordinate, fitting the curve to obtain a standard curve function formula of the absorption intensity-carbon content, testing the sample to be tested, and analyzing CO 2 Data of maximum absorption intensity, carry-in labelAnd calculating to obtain the carbon content in the sample by a quasi-curve function formula.)

1. A method for detecting the carbon content of coal-series kaolinite rock and a calcined product by thermal analysis-infrared combined detection is characterized by comprising the following steps:

weighing a coal series kaolinite rock with known carbon content and a calcined product standard sample, putting the coal series kaolinite rock and the calcined product standard sample into a thermal analyzer, introducing escaping gas into an infrared detector, and carrying out thermal analysis-infrared combined test according to a fixed heating rate to obtain a three-dimensional infrared absorption spectrogram containing three coordinate axes of wave number, absorbance and time;

step two, selecting CO from the three-dimensional infrared absorption spectrogram₂Analyzing the corresponding CO at the time point when the infrared absorption of the gas is maximum₂Extracting the maximum absorption intensity number corresponding to the carbon content from the gas two-dimensional infrared absorption spectrogramAccordingly;

step three, repeating the step one and the step two, respectively testing and analyzing at least four standard samples with different carbon contents to obtain a series of data of carbon content-maximum absorption strength, wherein the heating rates adopted in the process are consistent, and the mass error of the test sample is controlled within five percent;

step four, drawing a curve chart by taking the absorption intensity data as a horizontal coordinate and the carbon content data as a vertical coordinate and fitting the curve to obtain a standard curve functional expression of the absorption intensity-carbon content;

step five, carrying out thermal analysis and infrared analysis combined test on the sample to be tested according to the same quality and temperature rise rate as those of the standard sample test, and analyzing the data of the maximum absorption intensity;

and step six, substituting the maximum absorption intensity data of the sample obtained in the step five into the standard curve function expression of the absorption intensity-carbon content obtained in the step four, and calculating the carbon content in the sample.

2. The method for detecting the carbon content of the coal-series kaolinite rock and the calcined product by the thermal analysis-infrared combined method according to claim 1, wherein a balance with the precision of more than ten-thousandth is adopted for weighing the standard sample in the first step, and the sample amount is controlled to be 1-10 mg; the fixed heating rate is between 1 ℃/min and 20 ℃/min; before the experiment, the sample is dried, and before the temperature is raised, the thermal analysis and infrared combined system is subjected to protective gas sweeping.

3. The method for detecting the carbon content of the coal-series kaolinite rock and the calcined product by using the thermal analysis-infrared combined method as claimed in claim 1, wherein in the second step, if the tested three-dimensional infrared absorption spectrogram has a phenomenon of obvious inclination, baseline correction treatment is carried out during analysis.

4. The method for detecting the carbon content of the coal-series kaolinite rock and the calcined product by the thermal analysis-infrared combined method according to claim 1, wherein in the third step, the weighing deviation is controlled within five percent each time a standard sample with different carbon content is weighed; the number of the standard samples is 4-6; the variation range of the carbon content in the standard sample covers the variation range of the carbon content in the sample to be detected.

5. The method for detecting the carbon content of the coal-series kaolinite rock and the calcined product by the thermal analysis-infrared combined method according to claim 1, wherein the correlation coefficient of the function fitting in the four media of the step is not lower than 0.98.

6. The method for detecting the carbon content of the coal-series kaolinite rock and the calcined product by using the thermal analysis-infrared combined method according to claim 1, wherein the deviation between the mass of the sample to be detected and the average mass of the standard sample in the fifth step is controlled within five percent; before the experiment, the sample is dried, and before the temperature is raised, the thermal analysis and infrared combined system is subjected to protective gas sweeping.

7. The method for detecting the carbon content of the coal-series kaolinite rock and the calcined product by the combination of thermal analysis and infrared rays as claimed in claim 2 or 6, wherein the protective gas is high-purity nitrogen, neon or helium.

Technical Field

The invention relates to the technical field of test analysis, in particular to a method for detecting the carbon content of coal-series kaolinite rock and a calcined product by combining thermal analysis and infrared.

Background

Coal-series kaolinite rock is a special resource for producing high-quality calcined kaolin in China. The calcined coal series high-collar soil product has excellent physical, chemical, optical and other properties, and is applied to various fields of papermaking, electromagnetism, coating, optics and the like. Coal-derived kaolinite rock is usually associated with coal mines and therefore contains some carbon. The coal-series kaolinite rock must be calcined to remove carbon sufficiently so as to be utilized. Because coal-series kaolinite rock formation conditions vary widely, there is generally a large fluctuation in carbon content. The calcined coal series kaolin product is influenced by the calcination working condition, and the decarburization degree is different. Therefore, in the research and production of coal-series kaolinite rock, an analysis method which is rapid, accurate and suitable for carbon content change is needed.

The existing carbon analysis methods mainly have two types: one is a loss-of-ignition calorimetry method, which comprises the steps of measuring the heat value of the coal-series kaolinite rock in the heating process, carrying out quantitative analysis on the generated gas product, and finally calculating to obtain the carbon content. However, the method has the defects of long analysis period and large analysis error of a trace carbon content sample. The second one adopts a carbon-sulfur instrument. The principle of the high-frequency infrared carbon-sulfur instrument suitable for the material industry is as follows: heating a small amount of sample at high temperature under oxygen-rich condition to oxidize carbon in the sample into CO₂And measuring the infrared absorption spectrum of the gas, and carrying out quantitative calculation by using the infrared absorption spectrum to obtain the carbon content of the sample. However, such instruments usually employ a single point calibration method, in which a standard sample with a known carbon content is first analyzed, a reference carbon content is set, then a sample with a carbon content close to the reference carbon content is analyzed, and the CO of the sample and the standard sample are compared₂Infrared absorption spectrum, thus obtaining the carbon content of the sample. The method is suitable for the rapid analysis occasion with little change of the carbon content of the sample, but the accurate result can not be obtained for the sample with unknown carbon content or the sample with large fluctuation range of the carbon content. Therefore, the two common methods for analyzing the carbon content have certain limitations in the aspect of analyzing the coal-series kaolinite rock and the calcined product.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a method for detecting the carbon content of coal-series kaolinite rock and a calcined product by combining thermal analysis and infrared analysis, wherein the infrared analysis is used for CO₂The gas sensitivity characteristic is improved by adopting a multi-point calibration and baseline correction methodThe degree and the applicability to the wide-range change of the carbon content, thereby providing a generally applicable carbon content analysis method for the comprehensive utilization research and production of the coal-series kaolinite rock.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a method for detecting the carbon content of coal-series kaolinite rock and a calcined product by thermal analysis-infrared combined detection, which comprises the following steps:

weighing a coal series kaolinite rock with known carbon content and a calcined product standard sample, putting the coal series kaolinite rock and the calcined product standard sample into a thermal analyzer, introducing escaping gas into an infrared detector, and carrying out thermal analysis-infrared combined test according to a fixed heating rate to obtain a three-dimensional infrared absorption spectrogram containing three coordinate axes of wave number, absorbance and time;

step two, selecting CO from the three-dimensional infrared absorption spectrogram₂Analyzing the corresponding CO at the time point when the infrared absorption of the gas is maximum₂Extracting maximum absorption intensity data corresponding to the carbon content from a gas two-dimensional infrared absorption spectrogram;

step three, repeating the step one and the step two, respectively testing and analyzing at least four standard samples with different carbon contents to obtain a series of data of carbon content-maximum absorption intensity, wherein in order to ensure accurate measurement, more than four standard samples with different carbon contents need to be tested, the adopted heating rates need to be consistent, and the mass error of the tested samples is controlled within five percent;

step four, drawing a curve chart by taking the absorption intensity data as a horizontal coordinate and the carbon content data as a vertical coordinate and fitting the curve to obtain a standard curve functional expression of the absorption intensity-carbon content;

step five, carrying out thermal analysis and infrared analysis combined test on the sample to be tested according to the same quality and temperature rise rate as those of the standard sample test, and analyzing the data of the maximum absorption intensity;

and step six, substituting the maximum absorption intensity data of the sample obtained in the step five into the standard curve function expression of the absorption intensity-carbon content obtained in the step four, and calculating the carbon content in the sample.

Further, in the first step, a balance with the precision of more than ten-thousandth is adopted for weighing the standard sample, and the sample amount is controlled to be 1-10 mg; the fixed heating rate is between 1 ℃/min and 20 ℃/min; before the experiment, the sample is dried, and before the temperature is raised, the thermal analysis and infrared combined system is subjected to protective gas sweeping.

Further, in the second step, if the three-dimensional infrared absorption spectrogram to be tested has a phenomenon of obvious inclination, baseline correction processing is performed during analysis.

Furthermore, in the third step, when the standard samples with different carbon contents are weighed each time, the weighing deviation is controlled within five percent; the number of the standard samples is not less than 4, and is generally 4-6; the variation range of the carbon content in the standard sample covers the variation range of the carbon content in the sample to be detected.

Further, the correlation coefficient of the step four median function fitting is not lower than 0.98.

Further, the deviation between the mass of the sample to be detected and the average mass of the standard sample in the fifth step is controlled within five percent; before the experiment, the sample is dried, and before the temperature is raised, the thermal analysis and infrared combined system is subjected to protective gas sweeping.

Further, the protective gas is high-purity nitrogen, neon or helium.

The invention discloses the following technical effects:

compared with the prior art, the method solves the problem that the coal-series kaolinite rock and calcined products can be used for quickly and accurately analyzing samples with unknown carbon content or large fluctuation range, thereby providing a simple, convenient and accurate universal analysis method. The method can be used not only in the occasions with relatively stable carbon content, but also in the occasions with unknown carbon content or large fluctuation range in the sample. Meanwhile, the method is also applicable to the analysis of the carbon content of other carbon-containing samples.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a three-dimensional infrared absorption spectrum of a decomposition gas product of coal-series kaolinite in example 1.

FIG. 2 is a two-dimensional infrared absorption spectrum of standard samples of example 1 with different carbon contents.

FIG. 3 is a graph showing a fitting curve and application of the standard sample in example 1.

FIG. 4 is a graph showing the effect of applying the calibration curve in example 1.

FIG. 5 is a three-dimensional infrared absorption spectrum of a decomposition gas product of coal-series kaolinite in example 2.

FIG. 6 is a two-dimensional infrared absorption spectrum of standard samples of example 2 with different carbon contents.

FIG. 7 is a graph showing the fit curves and applications of the standard samples in example 2.

Fig. 8 is a graph showing the effect of applying the standard curve in example 2.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The specification and examples are exemplary only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.