Ceramics-Silikáty 51, (3) 153 - 159 (2007) |
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INFLUENCE OF PHOSPHATIC IMPURITIES ON THE ANHYDRITE BINDING MATERIAL OF PHOSPHOGYPSUM |
Cesniene Jurate |
Lithuanian Energy Institute, Breslaujos 3, LT-44403 Kaunas, Lithuania
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Keywords: Anhydrite, Phosphogypsum, Impurities, Hydration, Activators |
A possibility to use an unwashed, lime neutralized waste phosphogypsum - dihydrate calcium sulphate was analyzed in order
to obtain an anhydrite binding material. Influence of calcination temperature on the properties of the obtained material was
analyzed. It was determined that phosphoanhydrite calcined at 800°C temperature is characterized by optimal physical and
mechanical properties. Temperature influence on the phosphatic impurities (hydroxyapatite) of neutralized phosphogypsum,
which out of partially amorphous state transforms into the crystalline state, was analyzed. These impurities impede hydration
and hardening processes. Waste phosphogypsum, in which P₂O₅ does not exceed 1.7 %, is needed to produce the binding material.
In order to activate phosphoanhydrite binding properties, the influence of hardening activators was analyzed and their
optimal amount was determined. |
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