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，为粗粒含碳耐火材料的压力注浆成型应用开发合适的成型条件。研究了基于Dinger和Funk模型方法的不同粒度分布对耐火材料的流变和浇注行为、显微结构和性能的影响。主要挑战之一是开发合适的浆料组合物，其提供碳的足够润湿性并防止粗颗粒的沉降。使用了一种新型的、环保的粘结剂混合物。在优化悬浮液的流变行为之后，检查在压力过滤装置中由这些浆料形成的绿色体和在压缩渗透单元中滤饼的可压缩性。然后，在商业粉浆浇注机的铸造进行了研究。计算机断层扫描仪用于检测陶瓷中的缺陷，例如孔隙率中的空腔和梯度。此外，通过使用点过程统计的方法的图像分析确定所谓的序参量，并将其与取决于晶粒尺寸分布的材料性质相关联。该项目将通过近净成形技术为具有复杂几何形状的粗粒含碳耐火材料的新工艺提供基础，该技术具有改善的性能且不破坏粗粒。

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.