Pressing dynamics of disperse mixtures in analytical, diagram, and nomogram interpretations

• Published in: Refractories 1996, Vol.37 (7-8), p.231-238
• Main Authors: KHARCHENKO, I. G, KRASS, L. R, ANTONOV, G. I, KURZANOV, V. I
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Chemical industry and chemicals; Exact sciences and technology; Refractory products
• ISSN: 1083-4877; 0034-3102; 1573-9139
• DOI: 10.1007/bf02307295

A new approach to describing the pressing process in disperse refractory mixtures as transfer of the energy and mass of the substance into a spatial region that has the shape and size of the final product (greenware) is presented. A mathematical model in the form of differential equations of the transfer is developed. The notion of initial and boundary conditions is introduced. Analytical models for describing the time variation (in a pressing cycle) of the pressure fields over the cross section of a pressed item are suggested for different pressing regimes. The pressed items are classified as thin and massive bodies in accordance with the pressure difference and the mass criterion. The concepts of inertial and regular periods of the pressing cycle are introduced. Methods are developed for determining the coefficients of transfer of potential for the periods of the pressing cycle and a diagrammatic representation of the pressure fields over the cross section of the pressed item as a function of time. It is shown that, with a certain approximation, pressing equations suggested by different authors can be used for plotting mass concentration diagrams and predicting the compaction of the green on its surface and at the centre (in symmetric bilateral pressing). A nomogram is suggested for a compound and synchronous description of energy and mass transfer in the pressed item. This approach makes it possible to combine results of investigations in the theory and practice of refractory production into a single and elegant theory of this technological process, to predict its development and to work out its optimisation. 10 refs.