Analytical modeling of activation procedure applied in alpha-alumina thermo-mechanical synthesis

Abstract

The impact of the mechanical processing parameters on the alumina grain-size distribution affiliated characteristics and on the gamma to alpha phase transformation rate was investigated. The moderation in the alumina samples behavior has been correlated to the granulometric and mineralogical changes induced by activation via an ultra-centrifugal mill. The assessment of the activation process variables influence on the final quality of the product parameters was conveyed in order to optimize the mechanical treatment of the alumina, which otherwise could be regarded as either energetically or economically unsustainable procedure. The Response Surface Method, Standard Score Analysis and Principal Component Analysis were applied as means of the mechanical activation optimization. The r(2) values obtained by developed models were in range from 0.816 to 0.988. The established mathematical models were able to precisely predict the quality parameters in a broad range of processing parameters. The Standard Score Analysis emphasized that the optimal output sample was obtained using a sieve mesh of 120 mu m set of processing parameters (SS=0.96). Diverse comparison analyses disclosed that the optimal set of activation process parameters could reduce the negative effect of gamma-alumina samples immanent properties on the final score, and furthermore to enhance the rate of gamma to alpha transition which would improve energetic and economic sustainability of the alumina phase transformation procedure.