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对于萃取分离贵金属的基本化学,已进行了一系列研究,本文即是其中之一。用1,3,4-噻二唑-2-壬基巯基-5-硫醇(TNSTH)作萃取剂,从浓盐酸溶液(约5M)中萃取分离金(Ⅲ)和钯(Ⅱ)的含氯阴离子颇有希望。在该介质中的分配系数约为10~4。TNSTH可用来使多种贵金属互相分离。例如,金(Ⅲ)-铑(Ⅲ)和钯(Ⅱ)-铑(Ⅲ)的混合溶液的分离因数(即分配系数之比)为10~6;金(Ⅲ)-钯(Ⅱ)为145;钯(Ⅱ)-铜(Ⅰ或Ⅱ)为180;钯(Ⅱ)-铂(Ⅳ)为10~6。钯(Ⅱ)的半萃取时间约为6分钟,能满足工业生产的要求。TNSTH不萃取除铜以外的贱金属,所以这种萃取剂为贵金属同贱金属的分离提供了一种手段。就铜而言,所萃取的是铜(Ⅰ)而不是铜(Ⅱ)。钯(Ⅱ)萃合物中的化学计量比为Pd:TNSTH等于1:1.5。关于乙醇溶液中TNSTH同各种含氯阴离子所形成的络合物的性质的补充资料表明,所形成的各种络合物是Cu(TNST)、Ag(TNST)、Pd(TNST)_2和RhCl_3(TNST)_2。大多数金属可用硫脲-盐酸溶液反萃取(值得注意的例外是铑(Ⅲ)和(Ⅳ))。萃取剂TNSTH可认为是一种具有供电子的氮原子和硫原子的螯合试剂。
This article is one of a series of studies that have been conducted on the basic chemistry of extraction and separation of precious metals. (Ⅲ) and palladium (Ⅱ) were separated from the concentrated hydrochloric acid solution (about 5 M) by using 1,3-thiadiazole-2-nonylmercapto-5-thiol (TNSTH) Chloride anion quite promising. The partition coefficient in this medium is about 10-4. TNSTH can be used to separate multiple precious metals from each other. For example, the separation factor (ie, the partition coefficient) of the mixed solution of gold (III) -rhodium (III) and palladium (II) ; Palladium (Ⅱ) - copper (Ⅰ or Ⅱ) is 180; palladium (Ⅱ) - platinum (Ⅳ) is 10 ~ 6. The half extraction time of palladium (Ⅱ) is about 6 minutes, which can meet the requirements of industrial production. TNSTH does not extract base metals other than copper, so this extractant provides a means of separating noble metals from base metals. In the case of copper, copper (I) is extracted instead of copper (II). The stoichiometric ratio in the palladium (II) complex is Pd: TNSTH equals 1: 1.5. Supplementary data on the properties of complexes formed by TNSTH with various chlorine-containing anions in ethanol indicated that the various complexes formed were Cu (TNST), Ag (TNST), Pd (TNST) 2 and RhCl 3 (TNST) _2. Most metals can be back-extracted with thiourea-hydrochloric acid solution (notably rhodium (III) and (IV)). The extractant TNSTH is thought to be a chelating reagent with electron donating nitrogen and sulfur atoms.