Treatment of waste sulfuric acid copper electrolyte

Abstract

The aim of this paper was to investigate the possibility of using the copper anodes with high nickel content for electrolytic treatment of waste sulfuric acid copper electrolyte. Nickel content in each anode was about 10 wt. %. Lead, antimony, and tin content was within the limits ranged from 0.1 to 1.4 wt. %. Copper mass content in anodes was in the range from 86 to 90 wt. %, and was mathematical deference to 100 wt. %. Electrolytic processing was done in galvanostatic conditions at the current density of 250 A/m2, electrolyte temperature of 63 ± 2 ° C, duration of each test of 72 h. The mass of each anode was about 7 kg. The waste sulfuric acid electrolyte with concentration of 30 g dm3 Cu2+ ions and 225 g/dm3 SO4 2- ions was used as the working solution. Changing the anode mass, changing the content of copper and nickel ions in the working solution and the mass of obtained cathode deposit were the subject of discussion in this paper. The difference in weight of anode at the beginning and end of the process confirmed that the anodes are dissolved during the process. A significant reduction of Cu2+ ions concentration was achieved as well as an increase in concentration of Ni2+ ions in the working solution. Mass of cathode deposit, obtained during electrolytic refining of anode with the smallest impurity content, was greater than the mass of dissolved correspondent anode for about 2%. Mass of cathode deposit, obtained by refining the anode with the content of Pb + Sn + Sb from 1.5 to 3.5 wt. %, was less than the mass of dissolved correspondent anode by about 2 %.

Cilj ovog rada bio je da se ispita mogućnost korišćenja bakarnih anoda sa visokim sadržajem nikla za elektrolitičku preradu otpadnog sumporno-kiselog elektrolita bakra. Sadržaj nikla u anodama bio je oko 10 mas. %, a sadržaj olova, antimona i kalaja kretao se u granicama od 0.1 do 1.4 mas. %. Maseno učešće bakra u anodama bilo je u opsegu od 86 do 90 mas. % i predstavljalo je razliku do 100 mas. %. Elektrolitička prerada je rađena u uslovima galvanostatskog režima rada, pri gustini struje od 250 A/m2, temperaturi elektrolita od 63±2oC, u trajanju od 72 h. Masa svake anode bila je oko 7 kg. Otpadni sumporno-kiseli elektrolit sa sadržajem Cu2+ jona od 30 g/dm3 i sadržajem SO4 2- jona od 225 g/dm3 korišćen je kao radni rastvor. Promena mase anoda, promena sadržaja jona bakra i nikla u radnom rastvoru i masa dobijenog katodnog taloga bili su predmet diskusije u ovom radu. Razlika u masi anoda na početku i kraju procesa potvrdila je da su se anode tokom procesa rastvarale. Postignuto je značajno smanjenje koncentracije Cu2+ jona i povećanje koncentracije Ni2+ jona u radnom rastvoru. Masa katodnog taloga dobijenog elektrilitičkom rafinacijom anode sa najmanjim sadržajem nečistoća bila je veća od mase rastvorene korespodentne anode za oko 2 % dok su mase katodnih taloga dobijenih rafinacijom anoda sa sadržajem Pb+Sn+Sb od 1.5 - 3.5 mas. % bile manje od masa rastvorenih anoda za oko 2 %.