Abstract Prediction of micro processes, filter cake build-up and porous media flow is a key challenge to describe macroscopic parameters like filter cake resistance. This is based on a precise description, not only of the disperse solid fraction, but the distributed properties of the voids between the particles. Lab-experiments are carried out with alumina and limestone, which differ in particle size distribution (PSD) and resulting filter cake structure. Filter cakes of both materials are characterized by standardized lab tests and additionally, alumina cakes are measured with X-ray microscopy (XRM). Focusing on distributed process key parameters, the data gives a deeper understanding of the laboratory experiments. The solid volume fraction inside the feed strongly influences the particle sedimentation and leads typically to a top layer formation of fine particles in the final filter cake, which has a negative influence on subsequent process steps. The top layers seal the filter cake for washing liquid and increase the capillary entry pressure for gas differential pressure de-watering. The influence on cake structure can be seen in a change of porosity, particle size and shape distribution over the height of the filter cake. In all measurements, homogenous filter cake structures could only be achieved by increasing the solid volume fraction inside the suspension above a certain percentage, at which particle size related sedimentation effects could be neglected and only zone sedimentation occurred. XRM offers the chance to quantify these effects, which previously could only be described qualitatively.

中文翻译：

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固体体积分数对滤饼结构影响的显微断层扫描研究

摘要 微观过程、滤饼堆积和多孔介质流动的预测是描述滤饼阻力等宏观参数的关键挑战。这是基于精确的描述，不仅是分散的固体部分，而且是颗粒之间空隙的分布特性。实验室实验是用氧化铝和石灰石进行的，它们的粒度分布 (PSD) 和由此产生的滤饼结构不同。两种材料的滤饼均通过标准化实验室测试进行表征，此外，氧化铝滤饼采用 X 射线显微镜 (XRM) 进行测量。专注于分布式工艺关键参数，数据更深入地了解实验室实验。进料内的固体体积分数强烈影响颗粒沉降，通常会导致最终滤饼中细颗粒的顶层形成，这对后续工艺步骤产生负面影响。顶层密封滤饼用于洗涤液，并增加毛细管入口压力以进行气体压差脱水。从孔隙率、粒度和形状分布随滤饼高度的变化可以看出对滤饼结构的影响。在所有测量中，均质的滤饼结构只能通过将悬浮液内的固体体积分数增加到一定百分比以上来实现，此时与粒径相关的沉降效应可以忽略不计，只发生区域沉降。XRM 提供了量化这些影响的机会，