Problems and prospects of involving waste from polymetallic and iron ore processing in biological conservation

Abstract

Ore enrichment waste is a fine material that poses a serious environmental problem. However, the high residual content of rare and precious metals, as well as valuable metalloids, determines the preservation of technogenic formations as secondary mineral raw materials. This dictates the search for environmentally safe conservation of waste before its subsequent development. This report focuses on reducing the phytotoxicity of waste and the use of bioagumentation - the introduction of exogenous plant matter and azotobacteria into the root layer, which contributes to the optimization of the mineral nutrition of phytoconservants. The article examines the physical and chemical parameters of polymetallic ore dressing waste before and after chemical reclamation, provides information on changes in the composition of watersoluble forms of metal elements (Fe, Mn, Al, Cu, Zn, Cd, Co, Ni), a decrease in the anionic content of the sulfate ion, and the appearance of hydrocarbonates. It is experimentally established that after chemical reclamation of spent slags, their viability for seedlings of oats and white mustard increases. After reclamation, there is an increase in their morphometric indicators. Mustard reacts especially positively to the decrease in acidity and mobility of metals. The dry weight of its seedlings increases-by almost 30% compared to the control. When mustard seeds are inoculated with a suspension of a live culture of the bacterium Azotobacter chroococcum, its roots elongate and their weight increases. It is shown that the growth of mustard roots is also activated on iron ore processing waste that is subject to forest reclamation. But in such conditions, vital azotobacteria exhibit a glow, especially intense in small sand fractions. Chemolumi-nescent reactions ensure the survival of azotobacteria in the development of free radical reactions caused by the residual content of magnetic iron and lignin in the habitat. The revealed features of the growth of oat and mustard seedlings, as well as azotobacteria on ore dressing waste, should be taken into account when developing technologies to increase the biogenicity of the waste surface in vivo, to argue for the use of bioagumentation in creating technologies for environmentally safe waste conservation without involving the fertile soil layer - an irreplaceable natural resource.