激光粒度分析和筛分法测粒径分布的比较

分别采用筛分法和马尔文激光粒度分析仪两种方法对16种颗粒的粒径分布进行了测量。通过比较,发现两种测量手段得到的粒径分布结果存在较大的差异,马尔文激光粒度方法对颗粒粒径的测量结果偏小,受颗粒形状的影响很大;筛分法对微细颗粒的测量误差较大,但对大粒径颗粒的测量较为准确。通过对不同粒径段灰颗粒的显微照相,发现细颗粒的团聚是筛分法测量小颗粒结果偏小的主要原因。     

用激光法测定氧化铝磨损指数的探讨

用筛分法和激光法对氧化铝磨损指数进行了测定,分析和探讨了造成两种结果差异的原因。结果表明,用激光法可以测定氧化铝磨损指数,特别是对生产工艺稳定的工厂,可以起到指导控制生产的作用。对于粒度为45μm（含量〈10％）,同时磨损指数也〈10％的氧化铝能否用激光法测试磨损指数尚需进一步研究。     

几种常用的粉体粒度测试方法

介绍了几种常用的粉体粒度测试方法,如筛分法、沉降法、显微镜法、电感计数法、激光散射法以及电超声法等的测试原理、适用范围及注意事项,并对各种测试方法的优缺点进行了比较,最后对粉体粒度测试的发展方向进行了展望。     

超细高岭石粒径测试方法对比研究

以甲氧基嫁接高岭石复合物为前驱体,利用插层-剥片法对高岭石片层进行剥离,制得超细高岭石样品;以张家口高岭石原矿为对比测试样品,分别采用激光法、图像法和电阻法测试高岭石原矿样品和超细高岭石样品的粒径。结果表明:3种测试方法均可用于高岭石的粒径测试,测试结果相差较小,粒径变化趋势一致;高岭石原矿粒度分布分散,超细高岭石粒度分布集中;在张家口高岭石原矿粒径的测试中,激光法测试结果偏大,电阻法测试结果偏小,图像法测试结果居中,优先选择图像法;在超细高岭石粒径的测试中,图像法测试结果偏大,电阻法结果偏小,激光法测试结果居中,优先选择激光法。     

筛分法测定钛精矿粒度分布

采用干式筛分法(机械筛分法)对粗粒级钛精矿进行粒度分布测定研究,利用统计置信区间表征各粒级粒度分布测定结果。结果表明:按筛分终点原则确定合理的筛分时间为11 min;在测定次数为12,显著性水平α为0.05的条件下,重复测定的各粒级粒度分布测定值用格拉布斯准则判定未发现离群值;在测定次数为12的条件下,各粒级粒度分布测定值的相对标准偏差为1.0%~4.5%,精密度和重现性满足筛分法粒度测定的要求。     

激光粒度法与筛分法测量洗煤泥粒度分布对比

为了寻找能恰当描述高浓度黏稠物料粒度分布的方法,以洗煤泥为代表物料,通过筛分法与激光粒度法对比实验,研究激光粒度分析技术法应用于浓密膏体的可行性。结果表明,激光粒度法对于小粒径范围的测量更敏感,较筛分法更适于洗煤泥的粒度分析,推测该方法也适于其他种类浓密膏体的粒度分布测量。     

激光粒度测试结果影响因素分析

针对目前市面上激光粒度仪品牌、型号众多,但激光粒度测试结果差异较大的现象,以清华大学研制的球形石英粉标准样品为测试样品,使用不同厂家的激光粒度仪,通过激光散射法,对比不同复折射率下的检测结果,探究激光粒度测试结果的影响因素。研究发现,针对同种样品、不同厂家的激光粒度仪检测结果偏差较大。折射率与吸收率对粒度检测结果有较大影响,折射率的影响比吸收率的影响大,但随着吸收率增大可以逐渐抵消折射率的变化给粒度检测结果带来的波动,使检测结果趋于稳定。通过寻找拟合残差与粒度检测结果之间的变化规律,发现残差值越小,理论散射光强与实际检测光强的偏差越小,检测结果越趋于一个较稳定的值,但对比发现目前激光粒度测试用户根据残差值判断待测样品折射率的方法并没有可靠的依据。通过比较不同样品的最小残差值,发现同种样品的不同粒度区间对应的折射率与吸收率不同,从而证明粒度检测行业内以每种物质固定的折射率和吸收率来进行粒度测试的方法缺乏实际依据。     

几种常见粒度分析方法的比对研究

正一、概述颗粒的粒度分析方法很多。随着科技的进步,有些方法被逐步淘汰,有些方法得到了改进和发展(如激光衍射法、动态光散射法等),并在生产和科研中得到了广泛应用(如激光衍射法、显微图像法、电阻法、光透沉降法、筛分法等)。本文选择了目前常见的激光衍射法、显微图像法、电阻法、光透沉降法4种不同测量原理的粒度分析方法,邀请国内实验室合作进行比对实验,对粒度分布范围在(1~100)μm的玻璃微珠颗粒进行粒度分析,对各类统计粒径进行数据比对,以验证这几种粒度分析方法的一致性与可比性。     

筛分法和激光粒度法联合测定陆源碎屑岩粒度

用筛分法和激光粒度法联合测定陆源碎屑岩粒度,对激光粒度法的分析数据进行了校正,以保证两种方法的分析数据配套衔接.通过对比不同地质年代沉积岩的岩心校正前后概率累积频率曲线,校正后的曲线能更好地表征碎屑岩粒度的分布.对影响马尔文Mastersizer 2000激光粒度仪背景测量的进样器搅拌转速A、泵速B、超声强度C三个因子...     

氢氧化铝粉体粒度测量技术

氧化铝生产工艺分解过程中氢氧化铝粒度检测的结果对分解系统的稳定和产品氧化铝的粒度控制有着非常重要的意义。氢氧化铝粒度的测定方法很多,目前用来监测粒度的方法有筛分法、马尔文激光粒度法、库尔特全自动颗粒粒度分析、颗粒计数器分析等,综合各种分析结果可得到氢氧化铝的全粒度分布情况。     

Size distribution measurement of floating particles in the Allen region by a buoyancy weighing-bar method

The particle size distributions of spherical or cylindrical solid particles in the Allen region were measured using a buoyancy weighing-bar method. The particle size distribution obtained in the buoyancy weighing-bar method agrees with those measured by a laser diffraction/scattering method and a sieving method. The present study demonstrates that a buoyancy weighing-bar method is suitable for measuring the particle size distribution of a floating solid in the Allen region.     

Combination of Different Size Distributions for Mineral Particles by Applying Experimentally Determined Apparent Mean Shape Factor

As is well known, the behavior of systems of fine particles is strongly dependent on the size of the individual particles, and the size effects become increasingly important as the particles become progressively smaller. This study covers two different size analysis techniques, sieving and laser diffraction measurement, and constructs whole size distribution for different mill (ball and rod) products of some industrial minerals: barite and quartz minerals. A smooth overlap of corrected laser diffraction size distribution and sieve size distribution was obtained by applying the particle size with the apparent mean shape factor shifting to the right side of the curve for the rod-milled barite and ball- and rod-milled quartz. The apparent mean shape factors determined from the corrected particle size distributions were found to be 1.02 and 1.39 for ball- and rod-milled barite and 1.29 and 1.25 for ball- and rod-milled quartz, respectively. The results indicate that the ball-milled products of barite mineral have more regular (rounder in shape) particles than those of rod-milled barite, but there are not significant differences between the shape factors of ball- and rod-milled products of quartz mineral, i.e., both of them have irregular particles that deviate from spherical shape, as evident from the SEM pictures taken.     

Combination of Different Size Distributions for Mineral Particles by Applying Experimentally Determined Apparent Mean Shape Factor

As is well known, the behavior of systems of fine particles is strongly dependent on the size of the individual particles, and the size effects become increasingly important as the particles become progressively smaller. This study covers two different size analysis techniques, sieving and laser diffraction measurement, and constructs whole size distribution for different mill (ball and rod) products of some industrial minerals: barite and quartz minerals. A smooth overlap of corrected laser diffraction size distribution and sieve size distribution was obtained by applying the particle size with the apparent mean shape factor shifting to the right side of the curve for the rod-milled barite and ball- and rod-milled quartz. The apparent mean shape factors determined from the corrected particle size distributions were found to be 1.02 and 1.39 for ball- and rod-milled barite and 1.29 and 1.25 for ball- and rod-milled quartz, respectively. The results indicate that the ball-milled products of barite mineral have more regular (rounder in shape) particles than those of rod-milled barite, but there are not significant differences between the shape factors of ball- and rod-milled products of quartz mineral, i.e., both of them have irregular particles that deviate from spherical shape, as evident from the SEM pictures taken.     

Sizes influences of weighing bar and vessel in the buoyancy weighing-bar method on floating particle size distribution measurements

To evaluate the influences of particle migration lengths as well as the sizes of the weighing bar and vessel on the particle size distribution measured by the buoyancy weighing-bar method, we experimentally measured the size distribution of hollow glass beads as floating particles. The buoyancy weighing-bar method, microscopy, and laser diffraction/scattering method give similar particle size distributions. The variation coefficient of the buoyancy weighing-bar method is close to the value determined by the laser diffraction/scattering method. Moreover, the accuracy of the buoyancy weighing-bar method is equal to that of the laser diffraction/scattering method. For vessels with identical sizes, the particle sizes measured by the buoyancy weighing-bar method increase when the weighing bar is too thick or too thin. Additionally, the influence of the weighing bar length on the particle size distribution is not confirmed in the case of the hollow glass beads. Thus, to effectively employ the buoyancy weighing-bar method, the sectional area ratio of the rod/vessel must be 0.02–0.2.     

Particle shape effects on particle size measurement for crushed waste glass

Recently, narrow particle size distributions, as measured by sieve analysis, of crushed waste glass were used as a replacement for Portland cement in concrete. Their chemical reactivity was successfully studied as a function of this measure of particle size. Differences between sieve analysis and laser diffraction measures of particle size prompted this current re-analysis. Extremely careful sieving was used to divide the crushed waste glass particles into 0–25 μm, 25–38 μm, and 63–75 μm sieve size ranges, but laser diffraction did not agree with these particle size cutoffs. We use these same materials to try and understand the discrepancies between particle size as measured by laser diffraction and sieve analysis by using X-ray computed tomography followed by spherical harmonic analysis to measure the three-dimensional particle shape and size, as well as the length (L), width (W), and thickness (T) of each particle. We show how laser diffraction and X-ray CT results, along with sieve analyses, can be quantitatively related for these crushed waste glass particles in the approximate size ranges considered. In contrast to previous speculation, the particle width W does not have to correspond closely to the sieve opening – the correspondence depends on overall particle shape. In addition, we demonstrate how many particles are needed to analyze in order to achieve stable averages and distributions of the L/W, W/T, and L/T aspect ratios, which approximately define particle shape. These results have implications for how particle size is measured and interpreted in the cement and concrete and other industries.     

石墨微粉形状参数分布的研究

采用激光衍射法和沉降法的粒度分析结果,研究了石墨微粉颗粒的形状及其参数分布,给出了３ 种石墨微粉产品的长径比随粒径变化的分布曲线。通过对曲线的分析,可提取与颗粒制备机理有关的信息。本文从一个角度证明了颗粒的粒度分析与形状分析是相互影响、相互依存、不可分割的整体     

激光粒度仪颗粒联测的结果与评价

为了解不同激光粒度仪的硬件、软件等方面差异对粒度测量结果的影响,用4种颗粒形状不同的粉末在不同公司生产的激光粒度仪上进行测试。结果表明:激光粒度仪测试结果重复性很好;对于球形粉末和形状较规则的粉末,大部分激光粒度仪测得的中位径值之间可以比较;而粒径范围较宽和不规则形状粉末,个别仪器测量的中位径值有差异。     

多输出回归算法在超声粒径分布反演中的研究

悬移质粒径分布作为研究水体运动规律和水利建设中的关键参数,通过对Epstein-Carhart-Allegra-Hawley(ECAH)模型和超声衰减实验这类先验信息的研究,结合机器学习算法对悬移质颗粒粒径进行预测.根据超声衰减实验和其他相关物性参数提取特征,结合筛分法确定的粒径分布种类制作训练数据集和验证数据集,通过...