DISTRIBUTION OF AS IN TECHNOGENIC DEPOSITS OF THE KHOVU-AKSY TAILINGS DUMP (REPUBLIC OF TUVA, RUSSIA)
A.Sh. Shavekina1, S.B. Bortnikova2, S.S. Volynkin2, N.A. Abrosimova2
1Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Science,
Novosibirsk, Russia
Keywords: arsenic, supergene processes, secondary minerals, Khovu-Aksy, mineralogical and geochemical features
Abstract
The stored waste from processing arsenide Ni-Co ores of the Khovu-Aksy deposit (Republic of Tuva, Russia) is a unique geochemical system in which the joint behavior of As and metals (Fe, Co, Ni, Cu, Zn, Pb) under exogenous conditions can be directly traced. In the course of the study, the mineralogical and geochemical features of arsenic distribution from primary arsenides to newly formed phases and associated metals in waste with a high arsenic content (up to 4%) along the section of trench burial No. 3 were studied. A common characteristic of the entire thickness is a slightly alkaline environment with paste pH = 7.7, Eh 486 mV. Four horizons are distinguished in the section. According to elemental analysis (XRF-SI), accumulation of As, Mo, Pb, Sb, Co and Cu occurs in horizon 2 (80 cm), while Cd, Zn, Ni in horizon 3 (110 cm). In the processed ores, among non-metallic (rock-forming) minerals, quartz, calcite, dolomite, garnet, amphibole-chlorite aggregates, single grains of potassium feldspar (KFS), apatite, barite and muscovite are noted. Arsenic minerals are distributed extremely unevenly across the section, while they are not found in the soil horizon (horizon 4). Arsenic is found in the section in the form of: 1) its own As minerals: safflorite with howuaxite, conichalcite, scorodite, arseniosiderite, sarmientite, gernessite, annabergite, picropharmacolite; 2) isomorphic impurity in secondary formations (iron hydroxides by pyrite, amorphous silica, chloriteThe presence of carbonate minerals in primary ores and the applied technological scheme of ore enrichment with the technology of purifying solutions from arsenic directly affect the secondary mineral association of arsenic minerals.
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