Study on Pressed Reconstruction Techniques of Wasted Turquoise

The small particles of wasted turquoise are pressed reconstruction with Al (H₂PO₄)₃ adhesive solution.The results show that the weight of the adhesive, the size of the turquoise powder, the pressed pressure and time, the heat preservation temperature and time have the different effects on the pressed reconstraction experiments.The optimal process conditions are that the weight ratio between the adhesive and turquoise powder is 1∶4.The size of the particles is no less than 250 eyelet.The pressure is 1.5×10⁴~3.0×10⁴ MPa/m².Then after self-hardening at room temperature for 1~2 days, the turquoise body should be heated for solidify with a certain temperature curve.The colour of the turquoise body is uniform with light blue-green.The micro-hardness is 105~198 N/mm².The gemmological characteristics of the turquoise body, such as luster, refractive index, UV fluorescence and so on, are similar with that of the natural turquoise.The turquoise after pressed reconstruction experiments could be manufactured for turquoise beads and ring stones.