A QUANTITATIVE METHOD USING A LIGHT MICROSCOPE ON-LINE TO A MACINTOSH COMPUTER FOR THE ANALYSIS OF TREMOLITE FIBRES IN DOLOMITE

摘要

A modern method for quantitative determination of tremolite fibres in dolomite has been developed which uses light polarizing microscopy with phase-contrast equipment and evaluation on-line to a Macintosh computer. The principle is mass calculation based on fibre dimensions measured in the microscope with the help of a programmable multimedia program. The sample is leached in acid, gently crushed and sieved before a small portion is deposited on a cellulose nitrate membrane filter. The filter is made transparent with cinnamaldehyde on a microscope slide. The tremolite fibres will be coloured blue with a red to yellow halo when viewed under phase-contrast and thus easy to identify. An ordinary Macintosh computer with special video display cards and software, which enables the microscopist to perform on-line measurements of the fibre dimensions on a display with the help of a mouse, is used. The method does not differentiate between asbestiform and non-asbestiform tremolite. All particles/fibres of tremolite with an aspect ratio of ≥5:1 are measured. The method is very easy to use and the microscope as well as the computer hardware and software are not unusual.