On the Issue of Processing
Hydroxide Arsenic Sludges of Copper Refining Production
V. V. EGOROV, O. YU. MAKOVSKAYA, and YU. A. NAPOL’SKIH
Ural Federal University named after the first President of Russia Boris Yeltsin, Yekaterinburg, Russia
E-mail: yegorov_87@mail.ru
Keywords: hydroxide sludge, calcium metaarsenite, complexing agent, leaching, EDTA
Pages: 367-371
Abstract
The paper carried out X-ray phase analysis of arsenic sludge, whereby the following compounds were detected: (CaSO4) • 2H2O, Cu(OH)2, Ni(OH)2, Fe(OH)3, Ca(OH)2, and Zn(OH)2. The presence of arsenic (III) as calcium metaarsenite (Ca(AsO2)2) was also determined. Options for extraction
of non-ferrous metals from multicomponent hydroxide raw materials containing
significant amounts of arsenic were considered. Solutions of sulphuric acid,
ammonium salts, oxyethylidenediphosphonic (OEDP), ethylenediaminotetraacetic
acid (EDTA), alkaline metal tartrates were explored as reagent solvents. The
values for the logarithms of the stability constants of copper (II), nickel
(II), and calcium (II) complexes with appropriate ligands were presented.
According to experimental data, the use of substances that ensure the copper
and nickel extraction as complexes while maintaining pH > 5 allows for
almost complete elimination of arsenic dissolution. It was experimentally
proven that ammoniacal leaching and leaching in solutions of EDTA salts did not
lead to arsenic contamination of the filtrate ensuring copper and nickel
extraction from sludges. The use of EDTA and its salts also simplified
technology and equipment selection for further solution processing. The findings
led to the conclusion that the use of EDTA solutions at leaching of sludges of
neutralising industrial solutions was promising.
DOI: 10.15372/CSD20170405
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