2TiO₂・As₂0₅および2CuO・As₂O₅の解離圧測定

抄録

thermal dissociation pressure of 2TiO₂·EAs₂O₅ and 2CuO·EAs₂O₅ prepared by making a precipitate for each arsenate in a wet method have been measured using transpiration technique.
The dissociation temperature of these arsenates has been measured roughly by T.G.A. These dissociation reactions have been studied by X-ray analysis. The main results obtained are as follows.
1) The dissociation of 2TiO₂.As₂O₅ and. 2CuO. As₂0₅ proceeds in accordance with the following reactions.
2TiO₂·As2O₅ (s) =2TiO₂ (s)+1/2As₄O₆ (g)+O₂ (g)
3 (2CuO·As₂O₅)(s) = 2 (3CuO·As₂O₅)(s)+1/2As₄O₆ (g) +O₂ (g)
2)In Ar atmosphere these arsenates start decomposing at about same temperature of 800°C
3) The equilibriumconstant K_p of the above reactions in inert gas flow can be estimated by measuring the equilibrium pressure of As₄O₆. The relation oflogK_p and 1/T obtained are as follows.
2TiO₂·As₂O₅: 750°-850°C
logK_p=-21.480×10³/T+ 16.6
2CuO·As₂O₅: 725°-825°C
logK_p=-21.270×10³/T+16.0