| Iron ore is the basic raw material for the iron and steel industry,and the acidity of iron ore is an important factor affecting the iron and steel smelting production,so it is urgent to establish new technologies and methods for real-time online detection of iron ore acidity.Laser-induced breakdown spectroscopy(LIBS)is a new spectroscopic technique,which has the advantages of in situ,little or no sample preparation and no loss.It is widely used in metallurgy field.Calibration free method(CF-LIBS)does not require standard calibration to avoid the matrix effect,more suitable for on-site analysis,but the quantitative accuracy is not high.Based on the practical problems of improving the accuracy of iron ore acidity analysis,this paper analyzes the factors that influence the quantitative accuracy of CF-LIBS,and establishes the quantitative analysis method of Ca/Si ratio and its content in iron ore.This study is to improve the reliability of CF-LIBS quantitative analysis results,and to provide new methods and technical support for online on-line analysis of iron ore acidity.This paper is divided into four chapters.The main contents are as follows:Firstly,based on the assumption that the plasma temperature of the similar matrix was the same under the same conditions,the acidity of the iron ore was analyzed by CF-LIBS combined with BSA.First,the internal reference for self-absorption correction and the Boltzmann graph was constructed using the corrected analytical line,and the Ca/Si molar ratio was obtained by combining the Ca I and Si I intercepts in the graph with the Saha equation.A standard sample was introduced to determine the optimum plasma temperature with BSA,and using the temperature for the acidity analysis of samples.The results show that the calculated acidity of the unknown sample is close to the true value.The proposed method can effectively analyze the acidity of iron ore,and can provide reference for iron ore real-time online screening and industrial quality control.Secondly,the delay time of Ca I and Si I was optimized,and the self-absorption correction of Ca I and Si I lines was carried out.In order to eliminate the uncertainty of the instrument,O I was used to calibrate the spectral line.According to the principle of atomic emission spectrometry combined with the Saha equation,the numerical concentration of Ca and Si elements was calculated,and then the acidity of iron ore was calculated.The results show that the accuracy of this method is greatly improved compared with the traditional quantitative analysis method.Therefore,this method is an effective and reliable method for iron ore acidity analysis.Finally,the method of CF-LIBS combined with standard addition method is used to quantitatively analyze the acidity of iron ore.First,the self-absorption correction of the analytical line was carried out.Then,the Ca and Si contents are obtained according to the experimental parameters F.The results show that the proposed method is feasible in both theoretical and practical experiments.the reference element was introduced to avoid the limitation of all-element normalization of CF-LIBS,the operation is simple and fast,the quantitative result is accurate and the practicality is enhanced in this method,which meets the requirements of field experiments. |
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