Theoretical Prediction and Experimental Determination of Attrition Rates

When reasonably soluble substances (c*> 0.1mol l–1) are crystallized at a high specific power input and within their metastable zone, attrition is a primary source of nucleation. The study presented here is an attempt to quantify this attrition mechanism. Firstly, a physical model is introduced which relates the attrition resistance of a crystalline substance to its mechanical properties. In the second part, the emphasis is placed on the determination of the relevant mechanical properties, hardness, elastic constants, and fracture resistance. The physical model will finally be compared to experimental results. A good agreement is found between the experimentally determined and theoretically predicted attrition behaviour.

[1]  A. Mersmann,et al.  The brittleness of substances crystallized in industrial processes , 1995 .

[2]  H. Rumpf,et al.  Physical aspects of comminution and new formulation of a law of comminution , 1973 .

[3]  A. Mersmann,et al.  A new model of the effect of stirring intensity on the rate of secondary nucleation , 1989 .

[4]  D. M. Marsh,et al.  Plastic flow in glass , 1964, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[5]  A. Heijden,et al.  Growth rate dispertion: the role of lattice strain , 1992 .

[6]  Modeling of growth rate dispersion of citric acid monohydrate in continuous crystallizers , 1984 .

[7]  A. Mersmann,et al.  Initial-size-dependent growth rate dispersion of attrition fragments and secondary nuclei , 1992 .

[8]  Ian M. Hutchings,et al.  Energy absorbed by elastic waves during plastic impact , 1979 .

[9]  M. M. Chaudhri,et al.  Dynamic hardness, deformation and fracture of simple ionic crystals at very high rates of strain , 1981 .

[10]  D. Nelson.  Second and Higher Order Elastic Constants , 1992 .

[11]  J. Michell,et al.  Some Elementary Distributions of Stress in Three Dimensions , 1900 .

[12]  K. Puttick.  The mechanics of indentation fracture in poly(methyl methacrylate) , 1978 .

[13]  E. Yoffe,et al.  Elastic stress fields caused by indenting brittle materials , 1982 .

[14]  A. Mersmann,et al.  The influence of internal crystal perfection on growth rate dispersion in a continuous suspension crystallizer , 1995 .

[15]  A. Chianese,et al.  On the size distribution of fragments generated by crystal collisions , 1996 .

[16]  R. Hill.  The Elastic Behaviour of a Crystalline Aggregate , 1952 .

[17]  A. Maradudin,et al.  An Introduction To Applied Anisotropic Elasticity , 1961 .