Introduction
Upon IFPRI's request, this report contains a summary of the experimental and theoretical investigations on fracture and comminution at the Institute fiir Mechanische Verfahrenstechnik und Mechanik der Universitdt Karlsruhe.
In 1957, when Bans Rumpf started to build up the institute, comminution was a well established domain in engineering. Rumpf then had the idea to combine experience in engineering with the scientific methods of physics. This was the basis for a long period of successful research, lasting longer than Rumpf's life, which ended in 1976. In spite of comminution being only one of several quite different research activities in the institute, from 1957 to 1989 totaling 222 papers had been published on fracture and comminution. Most of the papers, however, are written in German and therefore widely unknown in Anglo-American countries.
Some of Rumpfs numerous PhD students were physicists. The first of them, Klaus Schbnert, initially assisted to realize Rumpfs ideas of a comminution science. Soon he became head of the fracture and comminution group which he directed for more than two decades. Under his influence most of the research in this field has been carried out at Karlsruhe. Since. 1981 Schijnert directs the Institute of Mineral Processing of the University of Clausthal.
To write this report, Klaus Schonert would have been the most appropriate person. Without his ideas and critic discussions, many of the highly complicated experiments in fragmentation and single particle comminution would not have been performed and many of the theoretical and experimental results would not have been found. It is difficult to distinguish today, which of some new ideas in fracture and comminution research were Rumpfs or Schdnerts ideas or the ideas of PhD students. Probably such a differentiation is unimportant. The period of successful research was not only the result of new ideas but even more a consequence of stimulation and leadership. Both, Rumpf and Schdnert highly motivated their co-workers.
Klaus Schlinert was not available, to write this report. The publications are available, however, and since I am knowing nearly all authors personally - some still from my time as undergraduate student - I have taken the risk to follow IFPRI's invitation to review three decades of comminution research in Karlsruhe.
This report is not a treatise on comminution. It will not describe and discuss the details of the various research projects. The objective of this review is the transfer of information about the activities of the comminution group at Karisruhe and their experimental and theoretical results. Detailed information can be found in the individual 222 papers.
In addition to the review, IFPRI wanted answers to some questions as well as recommendations for future research in comminution. These items are appended in this report.