Recovery of Chromium and Nickel from Industrial Waste

Abstract

The paper embodies an analytical approach to the recovery of chromium and nickel from different kinds of industrial wastes, namely, a Cr(III)-Ni(II) plating sludge, a Ni(II) plating mug, and a tannery effluent. The proposed methods employ precipitation, solvent extraction, and electrowinning steps. A toluene solution of Cyanex 923 is used as an extractant for the separation of Cr(III) and Ni(II) from some commonly associated metal ions such as Al(III), Fe(III), Mn(II), Co(II), Cu(II), Zn(II), and Pb(II). The experiments conducted up to 10 cycles indicate a negligible loss in extraction efficiency. The electrodeposition of Cr(III) and Ni(II) offers average cathode efficiencies around 40 and 75%, respectively. The recovered metals are 99.9% pure. The proposed procedures will be helpful in saving the wastage of metals and protecting the environment from metal pollution.

Performance Evaluation of Nickel Separation and Extraction Process from Simulated Spent Cr/Ni Electroplating Bath Solutions by ELM Process Using LIX63 and PC88A

“…To this solution, 0.01 mol=L Na 2 SO 4 , H 2 SO 4 , and DL-lactic acid were added as additives to adjust the chemical environment of the aqueous phase. [10,13,17,33] A sample of 2.0 mol=L of NaOH was then added to this solution to adjust the pH of the donor phase between 4.0 and 6.0. The initial concentration of divalent nickel and hexavalent chromium in the feed phase varied from 100 to 500 ppm throughout all the experiments.…”

“…Before the discharge of the electroplating solutions to environment at the end of electroplating process, Cr(VI) is reduced to Cr(III) by addition of sodium metabisulfite to convert more hazardous species of chromium to less hazardous one. [5,[10][11][12] Nickel is exposed to same operation together with hexavalent chromium. But nickel cannot be reduced to another oxidizing step due to its chemical nature.…”

“…After that operation, polyelectrolyte solid wastes are stored with landfilling. The average composition of the precipitated sludge is 21% Cr, 10% Ni, 4.2% Cu, 0.83% Fe, 0.52% Pb, 0.98% Zn, 0.24% Al, and 0.13% Mn, dried at 110 C. [10,[13][14][15][16] The toxic, semiprecious and the precious heavy metal contents of the electroplating waste solutions should be recycled or removed from the spent electroplating waste solutions before them converting to electroplating sludge due to high metal prices and storage difficulties. [17][18][19] The process for removing of heavy metals from aqueous solutions have been treated traditionally by a combination of physicochemical separation processes such as flocculation-precipitation and [20] filtration [21] and biological processes such as activated sludge and biofilm.…”

Recycling sodium dichromate in sodium chlorate crystallization mother liquor by nanofiltration membrane

“…In the existing process, chemical precipitations is often used to remove the sulfate radical in the crystallization mother liquor, which leads to the dichromate deposit to salt sludge together with sulfate, and finally causes chromium pollution (Gupta et al, 2002). Hexavalent chromium ion in dichromate will cause serious pollution to the environment and water source, thus do harm to fishing, forestry, agriculture and human health, and hexavalent chromium ion has a strong carcinogenic effect (Zhitkovich, 2011;Lone et al, 2013).…”

Design of experiments for statistical modeling and multi-response optimization of nickel electroplating process

“…In the last decades, many scientific and technical studies have been carried out to account for the effects of factors on electroplating performance and to address the enhancement of nickel electroplating process (Abd El Wahaab et al, 1986;Dolgikh et al, 2009;Njau et al, 1998;Tsuru et al, 2002;Hoffmann et al, 2008;Gupta et al, 2002;Yoshida et al, 2003Yoshida et al, , 2004Abdel-Hamid, 1998;Wang et al, 2008;Shpanko et al, 2004;Badarulzaman et al, 2009;Balakai et al, 2009;Sotskaya and Dolgikh, 2008;Mohanty et al, 2001;Ciszewski et al, 2004;Oliveira et al, 2006;Orinakova et al, 2006). However, it is worth to mention that most of such investigations dealt with conventional methodology of experimentation in which one factor is varied while others are fixed at constant levels.…”