Tri-calcium phosphate (ß-TCP) can be artificially synthesized by recycling dihydrate gypsum hardened

Abstract

Calcium phosphate is known as a major component of biological hard tissues. This study aimed to produce calcium phosphate by recycling kneaded surplus gypsum. β-dihydrate gypsum was derived from commercial dental β-hemihydrate gypsum, which was mechanically powdered and mixed with the liquid component of a commercial zinc phosphate cement. This mixture was fired at 1,200°C and evaluated by XRD analysis, thermal analysis and scanning electron microscopy (SEM). An acceptable ratio of mixing was 4 g of β-dihydrate gypsum powder to 1.5 mL of phosphoric acid liquid. XRD peaks were monotonic below 800°C, but new ß-TCP was formed by firing at 900°C or more, although TG-DTA analysis of synthetic ß-TCP suggested that some residual dihydrate gypsum remained in the sample. SEM images indicated a fused-block bone-like structure covered with phosphorus and calcium. These results suggest that production of synthetic β-TCP is possible through ecological techniques using recycled materials.

Synthesis of β-tricalcium phosphate by modifying the heating process of a dental casting mold

“…Furthermore, there have been many reports on the β-TCP synthesis method 11,14) . From such a point of view, we have reported on the synthesis method by mixing dental gypsum powder with an aqueous phosphoric acid solution and then firing them 23) .…”