Graphene-alumina nanostructured hybrid: synthesis with use dodecylamine and physicochemical properties

Combination of sol–gel and sonochemical techniques is suggested for producing a nanostructured graphene–alumina hybrid, which is a promising raw material for manufacturing fine-grained ceramics. This study focuses on the use of dodecylamine both in the sol–gel synthesis of Al-containing particles and in sonochemical graphene exfoliation. It has been shown that, when forming graphene–alumina composite in a reaction mixture of Al-containing sol and graphene suspension, graphene sheets take part as a template in the formation of a hybrid structure. Graphene sheets orient sol particles on their surface due to van der Waals interaction and control growth and direction of oligomeric gel chains. The graphene sheets limit the growth of Al-containing particles, which leads to an increase in the specific surface of the hybrid as compared to an alumina powder sourced from the same sol. The proposed approach enables the preparation of chemically homogeneous composite nanopowders with uniform distribution of components. © 2020 Taylor & Francis Group, LLC

A mathematical model for reactions during top-blowing in the AOD process:derivation of the model

Abstract In an earlier work, a fundamental mathematical model was proposed for side-blowing operation in the argon–oxygen decarburization (AOD) process. The purpose of this work is to present a new model, which focuses on the reactions during top-blowing in the AOD process. The model considers chemical reaction rate phenomena between the gas jet and the metal bath as well as between the gas jet and metal droplets. The rate expressions were formulated according to a law of mass action-based method, which accounts for the mass-transfer resistances in the liquid metal, gas, and slag phases. The generation rate of the metal droplets was related to the blowing number theory. This paper presents the description of the model, while validation and preliminary results are presented in the second part of this work