Aqueous pressure slip casting of coarse-grained, carbon-containing refractories

该项目的目的是在基础研究的框架内，为压力注浆技术在粗晶含碳耐火材料中的应用开发合适的成型条件。研究了基于Dinger和Funk模型的不同粒度分布对耐火材料的流变性、浇注行为、显微组织和性能的影响。主要的挑战之一是开发一种合适的浆料成分，提供足够的碳润湿性并防止粗颗粒的沉积。使用了一种新型的、环境友好的粘合剂混合物。在优化了悬浮液的流变性后，在加压过滤装置中检测了这些浆液形成的生坯，并在压缩-渗透室中检测了滤饼的可压缩性。然后，在商用注浆铸造机上进行了浇注试验。计算机断层扫描仪用于检测陶瓷中的缺陷，如孔洞和孔隙度梯度。此外，利用点过程统计量的图像分析方法确定了所谓的有序参数，并将其与依赖于晶粒度分布的材料属性相关联。该项目将为采用近净成形技术加工复杂几何形状的粗晶含碳耐火材料奠定基础，使其性能得到改善，粗晶不受损害。

The aim of the project is to develop in the frame of basic research suitable shaping conditions for the application of pressure slip casting to coarse-grained, carbon-containing refractories. The influence of different grain size distributions based on the Dinger and Funk model approach on the rheological and casting behaviour, the microstructure, and the properties of refractory is investigated. One of the main challenges is the development of a suitable slurry composition providing sufficient wettability of the carbon and preventing sedimentation of the coarse grains. A novel, environment-friendly binding agent mixture is used. After optimising the rheological behaviour of the suspensions, the green body formation from these slurries in a pressure filtration device and the compressibility of the cake in a compression-permeability cell are examined. Then, casting in a commercial slip casting machine is investigated. A computer tomograph is used for detecting flaws in the ceramic, such as cavities and gradients in porosity. Furthermore, a so-called order parameter is determined by image analysis using methods of point process statistics and correlated with the material properties depending on the grain size distribution. The project should provide the basis for a new processing for coarse-grained, carbon-containing refractories with complex geometries by a near-net shape forming technology, with improved properties and no damage of the coarse grain.