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In this article, we have examined the thermal behaviour of Moroccan phosphogypsum in the absence of additives. We have used very diversified techniques: thermogravimetric analysis (TGA), differential thermal analysis (DTA), infrared spectroscopy and X-ray diffraction. DTA has allowed us to point out several transformations. Moreover, TGA has shown that the dehydration can occur in one step, which confirms that the sample is not bihydrated. The infrared spectroscopy has allowed us to characterize the water molecules of crystallization and the sulphate grouping of phosphogypsum.

Neodymium oxide chloride single crystals up to 10 x 10 x 0.1 mm3 have been grown from molten neodymium chloride in the temperature range 900-700°C. A slow-cooling technique (3°C/h) with a sealed platinum-10% rhodium crucible was used. The best crystals are transparent, pale purple in color and have well developed (001) faces. They have been characterized by X-ray diffraction and optical measurements.