Crystallization tendency and the state of oxidic slags are important influencing factors for slag viscosity and therefore slag tapping. During the gasification process slag is constantly produced and flows down the gasifier walls until it is intercepted and stored for further treatment or a possible valorisation. The kinds of fuel used for gasification lead to different kinds of slag composition likewise. Slag viscosity is strongly influenced by the composition of the slag and the temperature. However, the process of crystallization represents another major influencing factor. Slag crystallization is also affected by several parameters, whose effects need to be considered in experimental studies. This study investigated the impact of the sample state, the chosen crucible material, and the oxygen partial pressure on the crystallization of a Fe-rich oxidic slag in the confocal laser scanning microscope (CLSM) experiment. Using sample powder may lead to heterogeneous nucleation and crystallization during heating due to heterogeneous melting of the compounds. The selection of crucible material is crucial to prevent alloy formation of Fe-species with Pt-crucibles under reducing atmosphere. Finally, the partial pressure of oxygen influences the crystallization tendency as well as the morphology of the crystallized phases. These parameters impede the reproducibility of results as well as the comparison with results deriving from other experiments like sample quenching. This contribution provides an enhanced understanding of the stated parameter effects on the experimental investigation of oxidic slags using the CLSM setup and yields advice to prevent experimental influence on the results.

中文翻译：

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CLSM实验中样品均质性，坩埚材料和氧分压对富铁氧化渣结晶的影响

结晶趋势和氧化渣的状态是影响炉渣粘度和出渣的重要因素。在气化过程中，炉渣会不断产生，并沿气化炉壁向下流动，直到被拦截和储存以进行进一步处理或可能的增值。用于气化的燃料种类也导致不同种类的炉渣成分。炉渣粘度受炉渣成分和温度的强烈影响。但是，结晶过程代表了另一个主要影响因素。矿渣结晶也受几个参数的影响，在实验研究中需要考虑其影响。这项研究调查了样品状态，所选坩埚材料，共聚焦激光扫描显微镜（CLSM）实验中氧分压对富铁氧化渣结晶的影响。由于化合物的异质熔融，在加热过程中使用样品粉末可能会导致异质形核和结晶。坩埚材料的选择对于防止还原性气氛下防止Fe物种与Pt坩埚形成合金至关重要。最后，氧的分压影响结晶趋势以及结晶相的形态。这些参数阻碍了结果的可重复性以及与其他实验（如样品淬灭）得出的结果的比较。