STUDY OF THE SURFACE OF PHOSPHORUS-CONTAINING FERTILIZER AND FEEDSTOCK BY EPISCOPIC MICROSCOPY

The paper presents the results of observation of phosphate raw materials and phosphorus-containing fertilizer by polarization microscopy. It is shown that the optical properties of the considered anisotropic microobjects are different in different directions and appear differently depending on the orientation of these objects relative to the direction of observation and the polarization plane of the incident light. The observation was carried out both in transmitted and reflected light. The light emitted by the illuminator was passed through a polarizer. The polarization imparted to it changed when the light subsequently passed through (or reflected from) the preparation under study. These changes were studied using the analyzer and various optical compensators. Analyzing such changes, a conclusion was made about the main optical characteristics of the studied anisotropic microobjects: surface color, strength of double refraction, number of optical axes and their orientation, rotation of the polarization plane, and dichroism. The binocular stereomicroscope NIKON Eclipse LV100DA was used. The main factor was to obtain a correct photographic image of the surface of the studied materials, suitable for further digital processing. The simplest and most convenient form is the imaging of samples by light-field episcopic microscopy. Due to the presence of irregular surface of the samples, imaging was carried out with different focusing for further image processing with the help of a specialized program in order to obtain the correct version of the image. The samples were photographed at magnifications of 200x, 500x and 1000x. To obtain a representative sample, at least four different areas of the light field were photographed.