Zinc Plant Uptake as Result of Edaphic Factors Acting

The influence of soil characteristics on the lability and bioavailability of zinc at both background and phytotoxic concentrations in Albic Retisol soil (Loamic, Ochric) was studied using various methods. Ranges of insufficient, non-phytotoxic, and phytotoxic zinc concentrations in soil solutions were established in an experiment with an aqueous barley culture. It was experimentally revealed that for a wide range of non-toxic concentrations of Zn in the soil corresponding to the indicative type of plant response, there was constancy of the concentration ratio (CR) and concentration factor (CF) migration parameters. As a result, a new method for assessing the buffer capacity of soils with respect to Zn (PBCZn) is proposed. The transformation processes of the chemical forms and root uptake of native (natural) zinc contained in the Albic Retisol (Loamic, Ochric) through the aqueous culture of barley were studied using a cyclic lysimetric installation and radioactive 65Zn tracer. The distribution patterns of Zn(65Zn) between different forms (chemical fractions) in the soil were established using the sequential fractionation scheme of BCR. The coefficients of distribution and concentration factors of natural Zn and 65Zn, as well as accumulation and removal of the metal by plants were estimated. The values of the enrichment factor of natural (stable) Zn contained in sequentially extracted chemical fractions with the 65Zn radioisotope were determined and the amount of the pool of labile zinc compounds in the studied soil was calculated.

Comprehensive Study on the Mechanism of Sulfating Roasting of Zinc Plant Residue with Iron Sulfates

Zinc plant residue (ZPR) is a secondary material generated during hydrometallurgical zinc production that contains considerable contents of valuable elements such as Zn, Cu, Fe, Pb, Cd, Ag, In, Ga, Tl. Zinc, copper and accompanying elements in ZPR are in different minerals, mainly in the ferrites. A promising approach for recycling ZPR is the sulfating roasting using iron sulfates followed by water leaching. In this study, the composition of ZPR and the obtained products were thoroughly investigated by various methods including X-ray diffraction analysis (XRD), chemical phase analysis and Mössbauer spectroscopy. The effect of temperature, amount of iron sulfates and roasting time on the conversion of valuable metals into a water-soluble form was thermodynamically and experimentally studied both using pure ferrites and ZPR. Based on the results of time-resolved XRD analysis and synchronous thermal analysis (STA), a mechanism of the sulfation roasting was elucidated. The rate-controlling step of zinc and copper sulfation process during the ZPR roasting was estimated. The sulfating roasting at 600 °C during 180 min with the optimal Fe2(SO4)3∙9H2O addition followed by water leaching enables to recover 99% Zn and 80.3% Cu, while Fe, Pb, Ag, In, Ga retained almost fully in the residue.

Identification and Metabolism of Naturally Prevailing Microorganisms in Zinc and Copper Mineral Processing

It has only recently been discovered that naturally prevailing microorganisms have a notable role in flotation in addition to chemical process parameters and overall water quality. This study’s aim was to assess the prevailing microbial communities in relation to process chemistry in a zinc and copper mineral flotation plant. Due to the limitations of cultivation-based microbial methods that detect only a fraction of the total microbial diversity, DNA-based methods were utilised. However, it was discovered that the DNA extraction methods need to be improved for these environments with high mineral particle content. Microbial communities and metabolism were studied with quantitative PCR and amplicon sequencing of bacterial, archaeal and fungal marker genes and shotgun sequencing. Bacteria dominated the microbial communities, but in addition, both archaea and fungi were present. The predominant bacterial metabolism included versatile sulfur compound oxidation. Putative Thiovirga sp. dominated in the zinc plant and the water circuit samples, whereas Thiobacillus spp. dominated the copper plant. Halothiobacillus spp. were also an apparent part of the community in all samples. Nitrogen metabolism was more related to assimilatory than dissimilatory nitrate and nitrite oxidation/reduction reactions. Abundance of heavy metal resistance genes emphasized the adaptation and competitive edge of the core microbiome in these extreme conditions compared to microorganisms freshly entering the process.

Processing of Anthropogenic Waste of Smelters of the Ural Mining and Metallurgical Company

The industrial sites of the smelters of the Ural Mining and Metallurgical Company have accumulated a lot of anthropogenic waste, the processing of which is currently economically impractical. These primarily include tailings and beneficiation tailings, as well as waste granulated and copper smelting slag. This article conducts studies on technologies for x-ray-radiometric/magnetic separation enrichment of discard slags of MMSK as well as using jigging machines. Slag and slag enrichment tailings are used for cement production and road construction. For complex processing of fine copper smelting dusts OJSC Chelyabinsk zinc plant developed, tested and implemented a special technology. After implementation of ”Actions to process industrial waste generated by UMMC enterprises at metallurgical enterprises of UMMC-Holding Corp.”, the following were noted: concentrators and special beneficiation facilities process slag; R&D on complete processing of concentrator’s tailings was conducted; smelting dust was not stored but processed in full; the technology of implementing Waelz process for processing of steel smelting dust has been developed and commercially tested; the technology for extraction of copper and precious metals from pyrite dross is to be improved. Keywords: anthropogenic waste, dust, tailings, slag, pyrite dross

On Diversification of Ore Mining Complex as Direction for Development of Depressive Economic System

The priorities for the development of the industrial complex are to compensate for market risks by dispersing activities into several types of business with the development of new products, the cost of which is reduced due to the use of the existing infrastructure. The prospects of mining enterprises of the North Caucasus in the implementation of production diversification are outlined. The results of substantiating the effectiveness of diversification at various volumes of ore mining in the conditions of the unprofitable Sadonsky lead-zinc plant with a graphical interpretation of economic calculations are given. The results of calculating the efficiency of involving substandard technogenic ores in the development, obtained by comparing alternative options that differ in the size of reserves, are given. An equation for the balance of values is proposed, which establishes the relationship between the volume of production and the completeness of extraction of reserves of deposits during the development of reserves of substandard ores and wastes. To assess the effectiveness of actions during diversification, an integral indicator of flexibility is proposed and the method of marginal analysis is used to reduce the uncertainty of situations. A graph of the relationship between the volume of ore production, economic indicators and the break-even point is shown. Okha-characterized the mineral resource base of diversified enterprises and diversification products for consumption by related industries. It is shown that the diversification of the ore mining complex is still a little used reserve for the development of the economic system of the depressive type.