索引源数据

The extraction and beneficiation of tungsten-molybdenum ores in the Dzhida ore district (Buryatia) were carried out for several decades. Sulfide-containing production waste in the form of technogenic sands with a total volume of more than 40 million tons has been accumulated over the years of the operation of processing plants. The tailings dumps are adjacent directly to the territory of Zakamensk town. Currently, the technogenic sand continues to pose a threat to the health of urban population and the environment. In this regard, the content of W, Mo, As, Fe, Mn, S and heavy metals (Cu, Zn, Ni, Pb) were determined in the technogenic sands. The content of Cu exceeds its permissible concentrations by 3.3–9.7 times, Zn exceeds by 4.2–10.9 times and Pb, by 5.5–25 times. The distribution of elements by grain size and along the vertical section of the tailings dump was studied. The forms of element occurrence were determined by geochemical forms. To find the elements forms, we used a five-stage sequential BCR extraction scheme in static mode. The standard sample BCR-701 was analyzed along with the studied samples. The results obtained indicate the influence of particle-size distribution on the content and mobility of elements. The ion-exchange form of elements is actively leached from dust and fine sand fractions. The mobility of elements from technogenic sands is also facilitated by high acidity of waste sulfide-containing ores. The pH of the water extract of technogenic sands is 3.3–6.8. Exceeding the maximum permissible concentrations of mobile forms of elements was revealed for Pb by up to 15.8 times, for Zn by 3.9 times, and for Cu up to 2.5–9.5 times. The nickel content in enrichment waste is lower than that required by regulatory documents. The studied technogenic sands contain fairly high amounts of Fe and Mn mobile forms, which are in the range of 83–112 mg/kg and 200–335 mg/kg, respectively. However, their values do not exceed standard quantities. Thus, the research results indicate that standards are exceeded and that ore waste has a harmful effect on the environment (Cu, Zn, Pb, Ni).