Study On Particle Size Characterizations Of Nanometer Suspensions And Coal-Water Slurries Based On Ultrasonic Attenuation Spectrum Approach

Ultrasonic attenuation spectroscopy is a relatively wide range of applications ofparticle size characterization technique. Because this method is based on simplestructure characterized by particle size, can achieve non-invasive measurement andreal-time online monitoring, and has the advantages of the sample without dilution,starting from the nineties of the20th century has been vigorously developing. Now,with the scientific and technological development and production process improvement,material science research has entered the nanotechnology era, in the food,pharmaceutical, chemical, energy and processing industries in the smaller particle size,which on process control and product quality made more stringent requirements, thusdemanding the measurement of particle size.In this study, starting from the theoretical model and experimental validation withultrasonic attenuation spectroscopy confirmed the nanoparticle suspension in the slurryand dynamic measurement of particle size distribution of the applicability and reliability.The first chapter introduces the theory of ultrasonic attenuation of the development andapplication at home and abroad, and pointed out the relevance of the research related tocontent and work; The second chapter describes the physical basis of ultrasound,ultrasonic attenuation and ultrasonic attenuation mechanism is established based on thetwo theoretical models, through the mechanism of ultrasonic attenuation analysis andcomparison of the difference between the two models are given and applications, andfinally introduces the actual process applied to the inversion algorithm; The thirdchapter researches the particle size characterization of nanoparticles suspensionexperimental study based on ultrasonic attenuation spectrum, we first confirmed the"long wavelength region," simplified model of particle size in the nano-particlesuspension of the applicability and reliability characterization, and through the largenumber of experiments to analyze the different materials, particle size and concentrationon the measurement of impact; fourth chapter describes the high concentration slurryultrasonic spectroscopy experimental station multi-parameter measurement and the usemade of this experimental test-bed research and use of invasive and non-invasivemethods of measurement were measured on the CWS; fifth chapter of conclusions andprospects.This study shows that the theoretical calculations and experimental results confirm the theory of ultrasonic attenuation spectroscopy can measure the lower limit to5nm,the measurement volume concentration range of0.5%to10%. Of which0.5%volumeconcentration of nano silver-water suspension of the particle size distributionmeasurements and transmission electron microscopy and centrifugal CPS measuredresults agree well prove the reliability of ultrasonic attenuation spectroscopy; on othernano-suspension of the particle size particle characterization results showed that whenthe volume concentration of the sample less than5%, the need to consider multiplescattering effect, when the volume concentrations higher than5%, you need to consider,but no matter what circumstances should possible to prevent the occurrence ofagglomeration. High concentration of coal-water slurry particle size measurementstudies have shown that ultrasonic attenuation spectroscopy measurements using highconcentration of slurry particle size distribution is entirely feasible, not only that, theexperiment using non-invasive measurement method and measured results invasivemeasurements and optical microscopy agree well with the measured results, indicating anon-invasive measurement method is reliable.