Development Of Sinter Basicity Analysis Technology Based On LIBs

Sinter is the main raw material for blast furnace ironmaking,which accounts for 90%of the charge.The quality level of the sinter directly affects the blast furnace condition and ironmaking output.Basicity is an important quality index of sinter,the fluctuation of which will cause fluctuations in the blast furnace temperature and slagging system.Severe fluctuations in basicity will lead to an increase in coke ratio and a decrease in blast furnace output.It is necessary to test the sinter basicity and feedback the information to the batching link in time to adjust the basicity of the sinter raw material to ensure the stability of the sinter basicity.However,the traditional analysis method of sinter basicity analysis has low efficiency and can not guide production in real time,which increases the cost of steel making.Laser Induced Breakdown Spectroscopy（LIBS）is a new type of atomic emission spectroscopy technology with fast analysis,multi-element analysis and in-situ detection which meet the needs of fast real-time analysis of sinter basicity.But there are few reports on the application of LIBS in the analysis of sinter basicity.Therefore,based on the characteristics of sintered ore samples,a sinter basicity analysis technology based on LIBS is developed to achieve rapid detection of sinter basicity.The main research contents are as follows:（1）Construction of multi-functional LIBS experimental platformIn order to carry out the research on sinter basicity analysis and study the factors affecting the LIBS signal of the sinter,a multi-functional LIBS experimental platform is built according to the LIBS principle and the characteristics of the sinter samples.The platform mainly includes lasers,delays,spectrometers,CMOS cameras,ICCD cameras,and 3D stages.the optical system is designed according to the experimental requirements.Multi-functional LIBS experimental platform has the following features:a)collecting plasma light signal;b)observing the sample surface micro;c)observing the laser verticality;D)observing of the transient process of the evolution of the laser plasma;E)height positioning of the sample stage;f)position adjustment of the fiber collection end.After testing,the experimental platform can achieve the above functions,and the construction of the multi-functional LIBS experimental platform provides hardware support for subsequent research and development.（2）Development of LIBS measurement and control softwareBecause the measurement and control methods of the various functional components of the LIBS experimental platform are not consistent,the traditional solution is to operate each component separately to complete the entire LIBS test,which undoubtedly reduces the detection efficiency.In this paper,an integrated LIBS measurement and control software is developed in the Linux system using the model/view structure to solve this problem,so that the functional components of the experimental platform can work together.Its structure mainly includes software interface,device control module,data access module,spectrum operation module,etc.,which implements control of functional components such as lasers,spectrometers,delays,CMOS cameras,data acquisition and storage,spectrum and image display,and according to the LIBS experimental process,each functional component is linked to realize automatic collection of LIBS experimental data.On this basis,the one-click storage and loading functions of experimental parameters and interface layout are added to speed up the experiment and improve the user experience.After testing,the developed LIBS measurement and control software meets the experimental requirements and can be used for the basicity analysis of the sinter in the LIBS experimental platform.（3）Quantitative analysis of sinter basicityA sinter analysis method combining LIBS and Random Forest Regression（RFR）is proposed to solve the problem of low efficiency of traditional sinter basicity analysis method to achieve rapid determination of sinter basicity.Firstly,based on the experimental platform and measurement and control software that has been built,the laser energy and delay time affecting LIBS performance are optimized by observing the changes of plasma transient image and spectral characteristics of sintered ore samples under different experimental parameters.Secondly,LIBS spectral data of 16 different sinter samples are obtained under optimized experimental conditions.Spectral data is used as input variable to establish basicity prediction model based on RFR algorithm,and two parameters(The number of decision trees-ntree and the number of random attributes-m_try)of RFR model are optimized by OOB error estimation.Then the RFR model is compared with the prediction model based on Partial Least Squares Regression（PLSR）.The correlation coefficient between the predicted and actual values of the RFR model is as high as0.983,which is greater than the maximum correlation coefficient value that is 0.9758 of the PLSR model.The results show that the predicted performance of the RFR for the sinter sample is better than the PLSR model.Finally,the RFR model was tested for repeatability.In 50 tests,the standard deviation of the predicted sinter basicity is 2.7%,which is good repeatability.The results show that LIBS combined with RFR is an effective analytical method for sinter basicity analysis.