Recovery of arsenic from Dashkesan cobalt ore tailings by combustion method with soda
A. A. HEYDAROV, A. B. MURADOVA, S. T. JAFAROVA, G. I. ALYSHANLY, S. KH. KALANTAROVA
Nagiev Institute of Catalysis and Inorganic Chemistry, National Academy of Sciences of Azerbaijan, Baku, Azerbaijan
Keywords: arsenic, combustion, dissolution, cobalt-containing concentrate, tailings
Abstract
The parameters for arsenic removal from Dashkesan ore enrichment tailings, which contain cobaltine (CoAsS), erythrite (Co3(AsO4)2⋅8H2O) and arsenopyrite (FeAsS), by combustion method with soda (Na2CO3) have been investigated. The processing method consists of two stages: 1) tailing/soda/coal mixture (molar ratio 1 : 1 : 0.2) was combusted at temperature 750 °C and time (1-3 h), 2) the combusted material was dissolved at 90 °C for 1 h in water with a phase ratio of S/L = 1 : 5. It was shown that the amount of As2O3 decreased from 5.47-6.19 to 0.52-0.71 wt%. The change of arsenic-containing phases in raw materials and processed products were studied by XRD, SEM/EDS and DTA/TG analysis methods. As the results of XRD analysis, the following arsenic-containing phases have been found in the combusted material obtained at 750 °C: sodium arsenate (Na3AsO4), sodium oxoarsenate (Na5AsO5) and scorodite (FeAsO4⋅2H2O). The residue obtained after dissolution is enriched with cobalt (CoO - 4.43 %) and can be considered as initial raw material for cobalt extraction.
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