| Kaolin resources in China were well known for their complete genetic types,abundant reserves and good texture.Kaolin in the field of rubber and plastics were mainly used for incremental packing,which aim at reducing the production cost of rubber and plastic products,and generally it was not functional.In recent years,with the development of the research of nanoscale clay in the world,it has become the focus of research to prepare a kind of functional clay material used in rubber and plastics.However,at present,the study of nanoscale clay was mainly based on montmorillonite clay,but the research based on kaolinite clay was relatively small,was still in the exploratory stage.The function of clay minerals in the rubber and plastic products was generally reflected in two aspects: one was to give the composite reinforced performance;the other was to give the composite barrier properties.This requires the clay filler having the following characteristics:(1)sheet structure,which can prevent liquids or gases through emissions;(2)small particle size,particle size was as small as possible,generally should be less than 1 ?m,which can give products good mechanical strength;(3)large radius-thickness ratio,more than 100 was preferable.(4)good dispersion.Because of the special layered structure,Kaolin has important application prospects in many chemical fields,but it needs effectively strip measure and feasible measure,especially the important parameter of kaolinite diameter thickness ratio plays a vital role for filling kaolinite reinforced material performance,but the calculation on diameter thickness ratio has the following problems:Different origin and types of kaolinite and other layered lamellar minerals(such as mica,talc,etc.)were studied in this paper.Mineralogy,petrology,statistics,fluid mechanics,numerical simulation and other research methods were used.A variety of particle size observation and measurement methods which were used commonly at home,such as microscopy,scanning electron microscopy,laser particle size analysis,sedimentation particle size analysis,resistance particle size analysis and other means,compared the domestic and foreign related research results,The possibility of calculating the size and diameter ratio of kaolinite by different measurement methods was discussed.The commonality and difference between the measured results were studied and analyzed.The theoretical basis of each measurement method was analyzed,and the difference between each measurement method was found and summarized.Potential links and changes in the law.Finally,the simple and efficient calculation method of kaolinite thickness ratio was established by the principle of correlation,complementarity and mutual transformation between the three methods of optical method,electron microscope and resistance method.And the CFD module of the multi-physics simulation software Comsol Multiphysics was used to demonstrate the dynamic restoration and feasibility of the test environment and the granular fluid force model.Finally,the mature kaolinite ratio calculation method was invented.Achieve the following achievements and awareness:The different test principles and complementarity between image method,optical method,electron microscope method and resistance method were compwered and discussed.The effective means of estimating the particle size of kaolinite was summarized and summarized.(1)Lamellar particles,of which the particle size was larger and the distribution was relatively concentration,such as kaolinite granules,talc,mica and so on.Combined with image processing software,the particle size was measured by image method,scanning electron microscopy and so on.It was easier to obtain the diameter of the lamellar particles,the process was simple,and the results were accurate.The difference between the two images was just a little.The main reason was that the mineral particles used in the sampling method were different(using scanning electron microscopy to select solid powder samples,using microscopic image method to disperse the sample into the solution),resulting in different degree of dispersion of the sample,there were some differences in the statistical measurement process,which was reasonable error.(2)The sedimentation method was more suitable for the particle size of the pellet.The BT1500 settler can effectively calculate the particle size data for the larger particle size,but it was often biased in the process of small particle measurement.The Sedigraph sedimentation analyzer was more efficient,but there was also a problem that the test limit was too high for small particles of flaky minerals and the test accuracy was not enough.(3)Using laser method to calculate the particle size of flaky particles,can effectively measure that particle size changes linearly with the processing time after kaolinite was intercalated or ground,it was easy to operate,the experimental results was continuous and reproducible,the only determination was that it has a little difference with the calculated particle size results,which was caused by the equivalent volume of the particles and the equivalent projection area of the flaky particles,so it was hard to avoid.(4)The resistance method is often used for particle size analysis of blood cells,but it is difficult to use for many industrial substances.Industrial and experimental mineral particle size test is usually used Marvin laser particle size tester.This paper focuses on the particularity of the principle of its resistance method-it can measure the true volume of the particles,combined with the special mineral morphology of kaolinite-lamellar particles,and carry on the in-depth analysis to the resistance method and the Kurt instrument And it is found that the pulse waveform in the process of measurement is closely related to the morphology of the tested particles.It has obvious advantages for the study of the aspect ratio of the kaolinite.(5)By observing the results of laser and resistance measurements on the same kind of samples,it can be found that the larger the particle layer,the greater the gap between the two.This is mainly caused by the Coulter method by measuring the particle size of the particle size data,and the laser method is mainly measured by the projected area of the particles,so the larger the area,the thinner the particles,the two methods of measuring the grain The greater the deviation of the diameter data.2.2.The radius-thickness ratio of kaolinite is an important parameter in many applications of kaolin,and there is not yet a good instrument and technique for accurate measurement.In this paper,the principle of measuring the radius-thickness ratio by using SEM scanning electron microscopy and Kurd method(resistance method)is discussed.The radius-thickness ratio of kaolinite with different particle size is calculated and analyzed.Having summed up and invented a single means of calculating the radius-thickness ratio of kaolinite.The main conclusions are:(1)The SEM image can be very intuitive to observe the diameter and thickness of kaolinite,and can be applied to instrument supporting software on mineral diameter and thickness for mass measurement,but the process needs to consume a large amount of manpower cost and electron microscope pictures,is currently the most accurate technique in diameter to thickness ratio calculation method.(2)The measurement and counting of particle size was based on the principle of resistance method,which reflects the relationship between the change of resistance and the volume of particles.The amplitude and width of the electric pulse were related to the morphology of lamellar particles such as kaolinite,As a basis for the thickness of the lamellar particles can be calculated.(3)By detailedly analyzing the output data and graphs of the Coulter instrument with the principle of resistance method,it is found that the electric pulse height reflects the volume of the particles.The electrical pulse width reflects the length of the particles passing through the holes,and comparing the standard spherical particles data can convert the pulse width data which takes time as a unit to particle size data.(4)Based on the principle of resistance method and the conversion of output data,formula of kaolinite thickness ratio was established:(?)(in the formula,W is measured pulse width of kaolinite sample(unit s),L is measured pulse height of kaolinite samples,where n(unit ?m);Wm(unit ?s),Wn(unit ?s)can be found in the tables.)3.In this paper,different measurement methods have different emphasis on the particle size of the experimental samples,the correlation between the methods and the complementary relationship between the measured results are compared.The method of measuring the ratio of diameter to thickness by laser-sedimentation method is summarized.A method of calculating the ratio of two kinds of kaolinite to thickness is measured by laser-Kurt method.Specific conclusions are:(1)The diameter of the particles of the lamellar is measured by laser method,since the concept of the laser particle size reflects the diameter of the particles with the same scattering effect.For the flaky particles,the value is closely related to the diameter of the sheet.Using the resistance method to calculate the thickness of the lamellar particles,the experimental results measured by the resistance method are expressed in terms of the diameter of the spheres of the same volume.According to the different calculation methods,the principle of calculating the diameter ratio is :(?)(Where d was the thickness of the tabular grains measured by the Coulter method,L was the diameter of the tabular grains measured by the laser method.)(2)The difference between kaolinite thickness ratio and the combined Kurdish method and laser method for the single use of the Coulter method is that for kaolinite with larger particle size,The results of the method are closer to the SEM statistical results,and the smaller particles are more accurate by the laser-Kurt method.4 In this paper,the motion model of kaolinite in laminar flow environment is analyzed and simulated by using Comsol Multiphisics simulation software flow module(CFD).The scientific and feasible method of calculating kaolinite ratio with Kurt's principle is studied and discussed.The method of simulating clay minerals by comsol software is summarized.Specific conclusions are:(1)The CFD was applied to the non-metallic mineral liquid motion environment model.It was a new idea to study the liquid phase force of the flaky particles by hydrodynamic calculation.Because CFD analysis can show the nature and phenomena of the system that other means can not reveal,and once given the parameters of the problem,CFD can quickly give the desired results,while simulation was an economic means of analysis can save a lot of manpower and resources.(2)According to the analysis of the statistics,flaky kaolinite particles in the liquid test environment,are more inclined to horizontal or near horizontal movement,the chip particles passing the test environment when moving vertically or near vertically were less than 1/10,It is speculated that the "flaky particles were mostly in a horizontal or near-horizontal state through the liquid phase test area".(3)The CFD module of Comsol Multiphysics simulation software was used to accurately simulate and predict the flow field of lamellar kaolinite in laminar flow environment.The kaolinite liquid motion trajectory model was established and the kaolinite The feasibility of calculating the kaolinite ratio was confirmed by the transient force analysis in the flow environment,and the motion trajectory of kaolinite in the liquid environment was dynamically demonstrated.Kaolinite radius-thickness ratio test method belongs to the more cutting-edge science and technology,there was no uniform international testing methods.Based on the verification of the radius-thickness ratio of kaolinite by image method,this paper presents two methods of resistance measurement and laser-resistance combined method,and uses CFD module of Comsol Multiphysics simulation software to establish liquid Force model to verify the accuracy of this method.The following were some of the shortcomings of the exiting further study and discussion,as well as the need for further work in the future.When using the laser-sedimentation method to measure the diameter and radius-thickness ratio of the pellets,for the Sedigraph sedimentation instrument was expensive and has less scientific research.It was usually used in the large-scale cement plant to monitor the product quality,so it can only measure samples in the work gap of the instrument,the sedimentation test data is just a little,can not be fully compared with other particle size measurement methods,resulting in this part discussing on calculating the radius-thickness ratio by the method of the laser-sedimentation method is not sufficient,and the follow-up work in this direction can do more attempts.At present,there was no special instrument to test the radius-thickness ratio at home and abroad.Professional companies can produce the instruments to test the radius-thickness ratio of mineral particles according to the theoretical method provided in this paper.Developing targeted professional software,embedding in the relevant formula to calculate the software kaolinite radius-thickness ratio.Click the click function to output the aspect ratio report function.The follow-up researchers can be used as a research direction,the difficulty of this study is the production and calibration of professional equipment.Calibration requires a large number of samples as calibration test supplies,resulting in a recognized accuracy. |
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