Separation And Deep Processing Of Copper, Palladium And Nickel In Copper - Palladium - Nickel Alloy Extraction

The recovery technology of copper, palladium and nickel from stripping solution of copper base-palladium nickel alloy was mainly studied in this thesis. Using thiocyanate to precipitate copper was proposed by which copper can be directly separated and recovered in the form of product. Using membrane electrolysis technology to recover palladium from stripping solution without copper and using the same technology to make deposited palladium into solution to prepare palladium chloride further. Using membrane electrolysis technology to recover nickel from stripping solution without copper or palladium, changing experimental conditions to determine the optimal process parameters.Method of using thiocyanate to precipitate copper studied the influences of concentration of Cu²⁺, dosage of sodium thiocyanate, aging time, dosage of sodium sulfite and temperature on the effect of removing copper. Under conditions of concentration of Cu²⁺ 0.06 mol/L, mole ratio among Cu²⁺, sodium thiocyanate and sodium sulfite 5:20:3, aging time 24 h and temperature 30 ℃, Cu²⁺ residues in solution was only 0.025mg/L. On the basis of depositing copper, adding 1.5g/L PEG and improving temperature to 50 ℃, cuprous thiocyanate superfine powder which average particle size was 0.472μm could be prepared.Membrane electrolysis technology to recover palladium studied the influences of kinds of membranes, concentration of Pd2+, current density and electrolysis time on the effect of depositing palladium. Changing cathode covered palladium into anode and using membrane electrolysis to prepare palladium chloride, influences of current density, concentration of HCl in anode solution and polar distance on the effect of electrolysis were studied. Under conditions of anionic membrane electrolysis, concentration of Pd2+ 5 g/L, current density 250 A/m² and electrolysis time 2.5 h, depositing rate of Pd was 97.43%. When using anionic membrane electrolysis to prepare palladium chloride, under conditions of current density 350 A/m², concentration of HCl in anode solution 1.0mol/L and polar distance 30 mm, current efficiency was 89.32% and energy consumption was 2532.43 kW·h·t^-1.Cationic membrane electrolysis to recover nickel studied the influences of two kinds of electrolyte NaCl and Na₂SO₄, current density, electrolysis time, stirring speed and temperature on the effect of electrolysis. Types of cathode materials also were studied. Under conditions of concentration of NaCl 2.5 g/L, current density 150 A/m², electrolysis time 8 h, stirring speed 800 r/min and temperature 35 ℃, depositing rate of Ni was 95.16%, efficiency was 86.87% and energy consumption was 5254 kW·h·t^-1. Using copper sheet as cathode could obtain high purity nickel powder.Through comprehension of above studies, this process could be thought to recover copper, palladium and nickel effectively from stripping solution.