On the problem of milling and ultrasonic treatment of asbestos and glass fibers in biological and analytical applications.

In preparing fiber suspensions for biological applications, as well as in many analytical procedures, the fibers--e.g. asbestos and glass--often have to be mechanically diminished and ultrasonically treated. Such treatments may sometimes produce changes in the physical and chemical properties of the original fiber samples. Measurements have been made to estimate the changes in fiber shape, size, and structure after milling and ultrasonic treatment. The results have shown that milling procedures not only change the size distribution, but also the particle shape and crystal structure of asbestos fibers. Ultrasonic energy (50 kHz) had practically no influence on the crystal structure, but in long-term applications it produces changes in fiber size and fiber concentration.