1.1本试验方法包括测定催化剂和催化剂载体颗粒的粒度分布，是几种对粒度测量有价值的方法之一。研究的平均粒径范围为1到300 μ m等效球面直径。该技术能够测量高于和低于该范围的粒子。有选择地测量粒子散射的激光的角度和强度，以便使用光散射技术计算体积分布。 1.2以国际单位制表示的数值应视为标准值。 本标准不包括其他计量单位。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 ====意义和用途====== 必须认识到，通过本试验方法或使用不同物理原理的任何其他粒径测定方法获得的结果可能不一致。 结果受到每种粒度分析方法所采用的物理原理的强烈影响。任何粒度测定方法的结果只能在相对意义上使用，在比较其他方法获得的结果时，不应将其视为绝对值。尤其是精细材料（即平均粒径 < 20 μ m） 不同制造商的激光散射仪器通常存在显著差异。这些差异包括不同波长的激光器、探测器配置以及用于将散射转换为粒度分布的算法。 因此，比较不同仪器的结果可能会产生误导。 用于测定粒径的光散射理论（夫琅和费衍射和米氏散射）已有多年的历史。一些测试设备制造商现在有基于这些原理的装置。虽然每种类型的测试设备都使用相同的光散射基本原理作为粒度的函数，但与理论应用相关的不同假设和将光测量转换为粒度的不同模型可能会导致每种仪器的不同结果。 此外，任何超出仪器尺寸测量范围的颗粒都将被忽略，导致报告的可检测范围内的百分比增加。在仪器检测极限处突然结束的粒度分布可能表明存在超出范围的颗粒。因此，使用该测试方法不能保证不同类型仪器的直接可比结果。 该测试方法可用于确定催化剂和载体的粒度分布，用于材料规范、制造控制和研发工作。 对于精细材料（即平均粒径 < 20 μ m） Mie散射理论的应用至关重要。这涉及输入 “ 光学模型 ” 包括 “ 真实的 ” 和 “ 虚构的 ” 固体在激光波长下的折射率。这个 “ 虚构的 ” 折射率也称为 “ 吸光度， ” 因为它对于透明材料（如玻璃珠）的值为零。对于常见材料和天然矿物（例如高岭土），这些值是已知的并已公布，通常包含在制造商中 ’ s仪器手册（例如，作为附录）。例如，在589.3 nm处测得的高岭石具有 “ 真实的 ” 折射率为1.55。矿物和金属氧化物的吸光度（虚成分）通常取0.001、0.01或0.1。许多公布的值是在589.3 nm（钠光）下测量的，但通常也给出了其他波长的值。因此，可以对所使用的激光波长进行外推、插值或估计。

1.1 This test method covers the determination of the particle size distribution of catalyst and catalyst carrier particles and is one of several found valuable for the measurement of particle size. The range of average particle sizes investigated was from 1 to 300 μ m equivalent spherical diameter. The technique is capable of measuring particles above and below this range. The angle and intensity of laser light scattered by the particles are selectively measured to permit calculation of a volume distribution using light-scattering techniques. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== It is important to recognize that the results obtained by this test method or any other method for particle size determination utilizing different physical principles may disagree. The results are strongly influenced by physical principles employed by each method of particle size analysis. The results of any particle sizing method should be used only in a relative sense and should not be regarded as absolute when comparing results obtained by other methods. Particularly for fine materials (that is, average particle size < 20 μ m), significant differences are often observed for laser light scattering instruments of different manufacturers. These differences include lasers of different wavelengths, detector configuration, and the algorithms used to convert scattering to particle size distribution. Therefore, comparison of results from different instruments may be misleading. Light scattering theories (Fraunhofer Diffraction and Mie Scattering ) that are used for determination of particle size have been available for many years. Several manufacturers of testing equipment now have units based on these principles. Although each type of testing equipment utilizes the same basic principles for light scattering as a function of particle size, different assumptions pertinent to application of the theory and different models for converting light measurements to particle size, may lead to different results for each instrument. Furthermore, any particles which are outside the size measurement range of the instrument will be ignored, causing an increase in the reported percentages within the detectable range. A particle size distribution which ends abruptly at the detection limit of the instrument may indicate that particles outside the range are present. Therefore, use of this test method cannot guarantee directly comparable results from different types of instruments. This test method can be used to determine particle size distributions of catalysts and supports for materials specifications, manufacturing control, and research and development work. For fine materials (that is, average particle size < 20 μ m), it is critical that Mie Scattering Theory be applied. This involves entering an “ optical model ” consisting of the “ real ” and “ imaginary ” refractive indices of the solid at the wavelength of the laser. The “ imaginary ” refractive index is also referred to as the “ absorbance, ” as it has a value of zero for transparent materials such as glass beads. For common materials and naturally occurring minerals (for example, kaolin), these values are known and published, and usually included in the manufacturer ’ s instrument manual (for example, as an appendix). For example, kaolinite measured at 589.3 nm has a “ real ” refractive index of 1.55. The absorbance (imaginary component) for minerals and metal oxides is normally taken as 0.001, 0.01 or 0.1. Many of the published values were measured at 589.3 nm (sodium light) but often values at other wavelengths are also given. Extrapolation, interpolation, or estimation to the wavelength of the laser being used can therefore be made.