title: A new membrane electro-deposition based process for tin recovery from waste printed circuit boards.
abstract: The current research investigated a process combining leaching, purification and membrane electrodeposition to recover tin from the metal components of WPCBs. Experimental results showed that with a solid liquid ratio of 1:4, applying 1.1 times of stoichiometric SnCl4 dosage and HCl concentration of 3.5-4.0 mol/L at a temperature of 60-90°C, 99% of tin can be leached from the metal components of WPCBs. The suitable purification conditions were obtained in the temperature range of 30-45°C with the addition of 1.3-1.4 times of the stoichiometric quantity of tin metal and stirring for a period of 1-2h; followed by adding 1.3 times of the stoichiometric quantity of Na2S for sulfide precipitation about 20-30 min at room temperature. The purified solution was subjected to membrane electrowinning for tin electrodeposition. Under the condition of catholyte Sn(2+) 60 g/L, HCl 3 mol/L and NaCl 20 g/L, current density 200 A/m(2) and temperature 35°C, a compact and smooth cathode tin layer can be obtained. The obtained cathode tin purity exceeded 99% and the electric consumption was less than 1200 kW h/t. The resultant SnCl4 solution generated in anode compartment can be reused as leaching agent for leaching tin again.
authors.affiliation: School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China. Electronic address: jianguang_yang@hotmail.com.
authors.forename: Yang
authors.initials: Y
authors.lastname: Jian-Guang
authors.affiliation: School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Jie
authors.affiliation: School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Si-Yao
authors.affiliation: School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China.
authors.forename: Lv
authors.initials: L
authors.lastname: Yuan-Lu
authors.affiliation: School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China.
authors.forename: Shi
authors.initials: S
authors.lastname: Wei-Qiang
keywords: Chloride leaching; Membrane electrodeposition; Tin recovery; WPCBs