Tourmaline is the chief boron-bearing mineral on the earth and is present in an excess amount in the crustal rocks. However, schorl is an iron-rich alkali that forms a solid solution with the magnesium-rich, alkali tourmaline, dravite. In this work, tourmaline (schorl variety) was treated along with soda ash, and its behavior was analyzed using electron probe microanalysis (EPMA), x-ray diffraction (XRD), scanning electron microscope, and energy dispersive spectrometer (SEM-EDS) analyses, thermogravimetric analysis (TGA), differential thermal analysis (DTA), in order to annotate the soda-ash activation of boron within the tourmaline ore. To extract boron from the sample, sodium carbonate powder was mixed with the schorl in 20% of the total weight of schorl powder. When the sample was treated with sodium carbonate, the sodium gets combined with the boron to form sodium borate at 566°C along with aegirine and aluminum oxides. This sodium borate can be treated with hydrochloric acid to get boron-oxide along with NaCl.
Part of the book: Extraction Metallurgy