Ceramics-Silikáty 49 (2) 120-125 (2005)

INFLUENCE OF THE TECHNOLOGICAL PARAMETERS ON THE STRUCTURE AND PROPERTIES OF HEMI-HYDRATE PHOSPHOGYPSUM

Z. Valancius, D. Nizeviciene, V. Leskeviciene, N. Kybartiene

Industrial way of the production of ortho-phosporic acid from apatite of various areas results in the waste product CaSO₄ 0.5H₂O having different structure and properties. To study the effect of the technological parameters on the formation of hemi-hydrate phosphogypsum, laboratory experiments of the decomposition of Kola apatites with sulphuric acid have been carried out and the properties of hemi-hydrate phosphogypsum investigated. The regulation the technological parameters of decomposition makes possible to obtain hemi-hydrate calcium sulphate which is characterized by well pronounced crystal structure and by good binding and physical-mechanical properties without additional processing.

Keywords: Hemi-hydrate phosphogypsum, Apatite, Crystals, Physico-mechanical properties