摘要
本文在298±1K下分别考察了N1923(B)-煤油溶液(Ⅰ)和N1923—P538(H_2A)—煤油溶液(Ⅱ)从1.00mol·L^(-1)(Na,H)Cl水相介质中萃取Au(Ⅲ)的平衡。结果表明,体系(Ⅰ)中萃合物组成为(BH)AuCl_4(BHCl)_3;体系(Ⅱ)中萃合物组成为(BH)AuCl_4(BHCl)_4,H_2A与BHCl形成缔合物(BHCl)_3·(H_2A)_(4·75)。
The equilibrium of The extraction of gold(Ⅲ) (C_(Au)=4.00 10^(-4)mol·dm^(-3))from 1.00 mol·dm^(-3)(Na, H)Cl solution with a mixture of primary amine N1923((?), R′+R=C_(19-23), B)and monoalkylp-hosphoric acid P538(RO—PO(OH)_2,R=C_(12-18),H_2A)in kerosine at 298±1K has been studied.The experimental relults are follows:
1. The determination of an aggregation number of amine salts, BHCl, formed by reaction of N1923(B) dissolved in kerosine with hydrochloric acid from aqueous solution have been performed by two phase emf titration. When the concentration of N1923 in organic phase are in the range of 0.001 mol·dm^(-3), the formation of aggregate as trimer was observed, by assuming the ideal behavior of each species in organic phase.
2. The extraction results of Au(Ⅲ) with N1923 kerosine solution (C_(BHCl(0))~0=0.003-0.019mol·dm^(-3)) show that the extraction machanism is anion exchange reaction described by eq.(1), where a=1.31, LogK_(ex)=4.30.
3. The extraction equilibrium of Au(Ⅲ) with a mixture of P538 (C_(H_2A(0))~0=0-0.05mol·dm^(-3)) and N1923(C_(BHCl(0))~0 0-0.06mol·dm^(-3)) in kerosine can be represented by eq. (2), a′(BHCl)_3(0)+ AuCl_4^-(?)(BH)AuCl_4(3a′-1)(BHCl)_((0))+Cl^- (2) and (BHCl)_(3(0))+(H_2A)_(q(0))(?)(BHCl)_3(H_2A)_(q(0)) (3)
C_(BHCl(0))~0=3[(BHCl)_3]_((0))+3[(BHCl)_3·(H_2A)_q]_((0))+3a′[Au]_((0)) (?)3[(BHCl)_3]((0))+3[(BHCl)_3·(H_2A)_q]_((0)) ( 4 )
C_(H_2A(0))~0=q[(H_2A)_q]_((0))+q[(BHCl)_3·(H_2A)_q]_((0)) (5) From eqs. (2)—(5) and [Cl^-]=1.00mol·dm^(-3), the eq. (6) can be obtained.
C_(BHCl(0))~0=3(D/K_(ex))^(1/α^′)+3q^(-1)[β^(-1)(D/K′_(ex))^((-1)/α′)+1]^(-1) C_(H_2A(0))~0 (6) The results show that the plots of C_(BHCl(0))~0 VS. C_(H_2A(0)~0 gave a good straight line at constant D (=C_(Au(0))/C_(Au)). The values of intercepts, b=3(D/K′_(ex))^(1/α′), and slopes, S=3q^(-1)[β^(-1)(D/K′_(ex))^((-1)/α′)+1] are changed by varying the values of D. Therefore, the values of a′, K′_(ex) and q can be calculated, thus a′=1.66; LogK′_(ex)=5.14 and q=4.75. From this, it can be seen that the extracted species, (BH)AuCl_4(BHCl)_4, in this system is large than that formed in the system containing N1923 only, and that P538 does not enter into it. The acidity in aqueous phase does not affect the extraction equilibrium of Au(Ⅲ). C_((0))~0 stands for the initial concentration of species in organic phase, [ ]_((0)) and [ ] stand for the equilibrium concentrations of species in the organic phase and in the aqueous phase, respectively.
出处
《山东大学学报（自然科学版）》
CSCD
1989年第1期71-77,共7页
Journal of Shandong University(Natural Science Edition)
关键词
萃取
金
N1923
extraction, gold, primary amine N1923
