四元交互体系Li^+,Na^+//CO_3^(2-),B_4O_7^(2-)-H_2O 298K相关系的理论预测及实验研究

Prediction and Experimental Verification of Phase Equilibrium in the Quaternary System Li^+,Na^+//CO_3^(2-),B_4O_7^(2-)-H_2O at 298 K

采用三元体系的溶解度数据 ,运用多元线性回归法拟合了 Li2 CO3(a) ,Na2 CO3(b) ,Li2 B4O7(c)的单盐参数、溶解平衡常数及有关的混合离子作用参数 .它们的值分别为 :β(0 )a =-1 .2 3 5 5 ,β(1)a =-2 .65 46,Ca=-0 .0 0 4660 7,β(0 )b =-3 .0 3 0 6,β(1)b =-3 .0 2 3 8,Cb=-0 .2 90 89,β(0 )c =-0 .2 93 0 4,β(1)c =2 .1 5 5 6,Cc=-0 .0 0 42 5 60 ,θL i,Na=1 .0 41 8,θB,C=-2 .63 0 5 ,ΨL i,Na,C=-0 .0 63 91 ,ΨL i,Na,B=0 .493 5 6,ΨL i,B,C=-0 .47842 ,ΨNa,B,C=0 .3 0 61 6,ln K(Li2 CO3) =-8.962 9,ln K(Na2 CO3· 1 0 H2 O) =3 .0 64 6,ln K(Li2 B4O7·3 H2 O) =-7.3 5 66,ln K(Na2 B4O7· 1 0 H2 O) =-7.4778.以盐的溶解平衡常数为判据 ,运用 Pitzer方程计算了四元体系 Li+,Na+//CO2 -3,B4O2 -7-H2 O 2 98K时的溶解度 ,并采用等温溶解平衡法 ,对该体系 2 98K时溶解度进行了实验测定 ,同计算值相比 。

Based on the solubility data of ternary systems, the single salt parameters and the solu bility product of Li 2CO 3(a), Li 2B 4O 7(b) and Na 2CO 3(c), and the corresponding mixing parameters have been fitted by the multiple linear regression method. Their values are: β (0) a=-1 235 5, β (1) a= -2 654 6 , C φ a=-0 004 660 7, β (0) b=-3 030 6, β (1) b=-3 023 8, C φ b=-0 290 89, β (0) c= -0 293 04 , β (1) c= 2 155 6 , C φ c= -0 004 256 0 , θ Li,Na = 1 041 8 , θ B,C = -2 630 5 , Ψ Li,Na,C = -0 063 910 , Ψ Li,Na,B =0 493 56, Ψ Li,B,C =-0 478 42, Ψ Na,B,C =0 306 16, ln K (Li 2CO 3)=-8 962 9, ln K (Na 2CO 3·10H 2O)=3 064 6, ln K (Li 2B 4O 7·3H 2O)=-7 356 6, ln K (Na 2B 4O 7·10H 2O)= -7 477 8 . The predicted solubility values of the quaternary system Li +,Na +//CO 2- 3, B 4O 2- 7 H 2O at 298 K are in good agreement with experimental results obtained from a isothermal method at 298 K.