| The development trend of the new cement industry is oriented towards environmentally friendly and resource-saving development.In the cement industry,the quality control of raw materials is the basis for ensuring the quality of cement clinker and products.The measurement of key components in raw materials is a key part of the regulation of the production process.In order to ensure the quality of cement raw materials,the percentage of four oxides containing Fe2O3,SiO2,CaO and Al2O3 must meet certain technical ratio indexes.The instability of the quality of the raw materials produced will cause large fluctuations in the raw material composition.If the ratio of the four key oxides of Fe2O3,SiO2,CaO and Al2O3 is not adjusted in time,the quality of the produced cement will be unstable or even unqualified,which directly caused waste of resources and loss of business.Therefore,it is an important technology to produce high-quality cement by obtaining the content of raw materials on the line and adjusting the ratio of raw materials on this basis.The commonly cement production quality testing methods are mainly X-ray fluorescence spectrometry(XRF)and prompt gamma neutron activation analysis(PGANN).XRF method has the characteristics of high sensitivity and easy to use,but it is essentially an off-line analysis method,which causes control hysteresis and the X-rays that are harmful to the human body.PGANN can analyze multiple elements online in real time with high accuracy.However,because of the neutron source is used in the technology,improper operation can cause irreversible damage to human health.Fourier transform infrared spectroscopy(FTIR)has great potential for the determination of cement raw meal components without the need for sample preparation,rapid and simple,and simultaneous measurement of various components.At present,there is no relevant research report on the quantitative analysis of cement components in FTIR in China,and overseas research is also in the early stage.Therefore,spectra was used to quantitatively analyze the cement raw materials Fe2O3,SiO2,CaO and Al2O3 by FTIR technique.Firstly,the FTIR quantitative analysis method for raw material composition analysis were introduced.The infrared spectrum characteristics of cement raw material minerals were studied.an online FTIR analysis system suitable for the field was designed for the application of industrial site analysis of raw meal components.Based on the requirements of FTIR analysis of the composition of cement raw materials,the diffuse reflection acquisition structure and the near-infrared band were determined.So the multi-source diffuse reflection collection structure specifically for industrial transmission chutes and the differential optical swing arm antiseismic interferometer were designed.An industrial online FTIR analysis system for raw material composition were bulit.Secondly,the diffuse reflection near-infrared spectra of cement raw material samples was collected by using the built system,and the contents of Fe2O3,SiO2,CaO and Al2O3 were measured by XRF method as reference values.The FTIR technique combined with partial least squares(PLS)was used to establish the initial quantitative analysis model for the four components of Fe2O3,SiO2,CaO and Al2O3 in cement raw meals.However,due to the complex industrial site environment and unstable air humidity,it will interfere with the on-line FTIR quantitative analysis of four key components of Fe2O3,SiO2,CaO and Al2O3 in raw meal samples.Therefore the cement raw material online FTIR analysis system was used to collect the near-infrared spectra of cement raw meal samples under different humidity conditions,and the effects of different humidity conditions on the quantitative analysis of near-infrared spectra were analyzed.Moreover,the particle size of the raw meal sample also has a certain influence on the quantitative analysis model of Fe2O3,SiO2,CaO and Al2O3.The on-line FTIR analysis system of cement raw materials was used to collect near-infrared spectra of cement raw meal samples of different particle sizes,and the effects of different particle size on the quantitative analysis of near-infrared spectra were analyzed.Since background moisture has a great influence on the quantitative analysis model of Fe2O3,SiO2,CaO and Al2O3,a near infrared spectroscopy modeling method of cement raw meal components by eliminating background moisture is proposed.Through the pure water absorption spectrum in the database,after matching the instrument information,the actual moisture absorption spectrum is obtained by fitting the pure water absorption spectrum using a nonlinear least squares method.After deducting the actual water absorption spectrum from the measured sample spectrum,a quantitative analysis model of the raw material composition without the background moisture interference is obtained by multivariate correction. |
PDF Full Text Request