Details of recycling of waste plating solutions

Plating platinum group metal surface layer on other metal substrates instead of platinum group metal overall metal parts, can greatly save the amount, of which Pt plating, Pd plating and Rh plating are more applications. Platinum plating is mostly used in jewelry, tableware and medical equipment, scientific instruments in the early days, but now it is widely used in chemical industry and cathodic protection of platinum-plated titanium anodes, electronic appliances, aerospace and other fields. Palladium plating is mainly used for electrical contacts, jewelry, watches and glasses frames decoration. Rhodium plating is mainly used for scientific instruments, microscopes, searchlights reflective irradiating mirrors and electrical contact devices, etc.

Composition and properties of electroplating solution: Preparation of electroplating solution and electroplating is the knowledge content of electrochemistry and electrical engineering, this section will only be briefly introduced as the knowledge of platinum group metals in terms of chemical properties and general knowledge of application.

I. Platinum plating solutions are:

1, chloroplatinic acid plating solution: containing H2PtCl6 15-25g/L, [HCl] > 1 mol/L.

2, alkaline plating solution: containing Na2Pt(OH)6 about 18g/L, Na2SO4 about 30g/L, NaOH about 5g/L, sodium oxalate Na2C2O4 about 5g/L;

Second, palladium plating solution has:

1, acidic palladium plating solution: containing Pd (PdCl2) about 50g/L, NH4Cl about 50g/L, pH 0.1-0.5;

2、Weakly alkaline palladium plating solution: containing Pd10-40g/L [added as Pd(NH3)2Cl2 salt], NH4Cl about 10g/L, (NH4)2SO4 about 25g/L, pH8.5-9.

III. Ruthenium plating solutions are

1. Ruthenium chloride plating solution: containing Ru about 2 g/L (added as ruthenium nitrosyl chloride RuNOCl3 compound), H2SO4 2 mol/L.

2. Ammonium sulfamate plating solution: containing Ru about 10 g/L [added as (NH4)3N(Ru2Cl4H2O)2 compound)], amine sulfamate 10 g/L , pH 1.3;

Fourth, cyanide molten salt plating solution: in NaCN + KCN mixture of molten salt (550-600 ℃), argon gas protection, respectively, electrolysis into Pt 3g / L or Ir 5-6g / L, as plating solution for platinum, iridium.

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