从废胶体钯中回收Pd工艺研究

Study on the Recovery of Palladium from Waste Colloidal Palladium

胶体钯用于印刷电路中电子元件连接用电路板(PCB)孔的金属化,对废胶体钯中的Pd需加以回收。本文提出加热破胶和氧化破胶2种回收Pd的方法,研究了稀释比、pH值对加热破胶法回收Pd的影响,以及王水用量、反应温度和时间对氧化破胶法回收Pd的影响。结果表明,采用加热破胶法,在稀释比=3,pH=1.3,100℃条件下破胶,加入王水溶解Pd沉淀物,采用氨水调pH=9～10,生成Pd(NH3)4Cl2,再用盐酸调pH=1～1.5生成Pd(NH3)2Cl2,经水合肼还原得到Pd(99.92%),回收率为98.79%;采用氧化破胶法,加入王水后在100℃下反应破胶,经上述相同的钯回收提纯工艺得到Pd,回收率仅为60.87%。

The colloidal Pd is mainly used in metallization of printed circuit board(PCB) hole for electronic component assembling Pd in waste colloidal Pd needs to recover. This paper put forward 2 methods to break the colloid for recovery of Pd: the heating method and the oxidation method, and investigated the effect of dilution ratio(water/colloidal Pd) and pH level on the recovery of Pd by heating method and that of amount of aqua regia, reaction temperature and time on the recovery of Pd by oxidation method. The results showed that using heating method, after colloid breaking under the condition of dilution ratio=3,pH=1.3,100℃,the aqua regia was added to solve the Pd precipitates, then adjusting the pH to 9～10 with ammonia forming Pd(NH3)4Cl2, and then adjusting the pH to 1～1.5 with hydrochloric acid forming Pd(NH3)2Cl2, which was then reduced to Pd(99.92% in purity) with N2H4?H2O; the recovery rate was 98.79%; however, using oxidation method, after addition of aqua regia at 100℃ to break colloid, Pd was recovered and refined by the above process, the recovery rate was only 60.87%.