Initial Development Of National Reference Material For Particle Size Measurement

With the development of technology and industrialization,a variety of new analytical instruments,testing methods and technologies are emerging in an endless stream.Reference material is an important criterion for testing the reliability of these new instruments and new technology,and is an important means to verify their metrological traceability.The reference material of spherical quartz is the first widely distributed national reference material in the field of particle size detection.It is also very important to complete the industrial standardization construction and promote the development of powder technology in China.This research belongs to the initial development stage of national standard samples for particle size measurement.The aim is to determine the raw materials and particle size detection method of national reference material for particle size determination.Exploring the production process of reference material.Testing the uniformity and stability of the reference material.The results of quantitative evaluation provide the basis for the production and technical upgrading of reference material.In this study,spherical silica powder was used as raw material to produce reference material for particle size detection.First,analyzing the influence factors of particle size detection,and developing a set of particle size detection method for reference material to minimize the detection error caused by these factors.Then using the natural sedimentation method and the sieving method to classify the raw materials,and calculating the mixing ratio by software.After the homogenization,the reference material were basically satisfied.In the preparation process,developing a set of automated wet grading system and a set of automated powder packaging equipment,economic and practical,which provide a great convenience for the production of reference material.The reference material showes good uniformity and stability produced by this study after the testing of pre-uniformity,uniformity and stability.The main results of this study are:1.The choice of complex refractive index has a great impact on laser particle size detection results.The real of the complex refractive index?refractive index?have a greater impact on the detection results than the imaginary?absorption rate?.The impact of different refractive indexes on the test results gradually become smaller,when the absorption rate increasing.For the same substance,there is a different refractive index in different particle size intervals during laser particle size detection.2.The method of selecting the complex refractive index by comparing the residuals is not correct.It is possible to get a small residual value when using a wrong refractive index for detection which can result in a larger experimental error.3.After the pre-uniformity test,uniformity test,stability test and quantity evaluation,the technical specifications of the reference material are:QSB40:D₁₀=11.716±1.535?m,D50=26.112±2.509?m,D₉₀=51.632±4.905?mQSB20:D₁₀=6.78±0.9942?m,D50=14.03±1.383?m,D₉₀=25.91±2.763?mQSB10:D₁₀=2.621±1.076?m,D50=6.112±0.7606?m,D₉₀=10.56±2.191?m...