Fine Copper Powders Production

The article is devoted to the description of a method for producing electrolytic copper powder with an average particle size of 3 to 10 μm. In order to increase the proportion of the finely dispersed fraction during the electrolysis process, the composition of the electrolyte was changed. In particular, the content of chloride ions was increased from 6 to 53 mg/dm3. After the growth of the powder in industrial baths, its subsequent drying and sieving on vibrating screens, samples were obtained with a fraction of 5 μm content in the range from 3 to 38 %. Additionally, air classification of powders was carried out at various speeds of the classifier rotor from 800 to 2000 rpm. Based on the results of the study, the optimal ranges of the specific surface area and the size of the initial powder particles before classification, as well as the composition of the electrolyte and the operating modes of the classifier, were determined.

Continuous copper leaching technology

The parameters of the continuous technological process of leaching copper from fine copper waste using nitric acid as an oxidizer are studied. Optimal conditions for a continuous leaching process were established, in which solutions with a mass concentration of copper ions greater than 25 g/dm3 were obtained.

Melt Spinning of Highly Stretchable, Electrically Conductive Filament Yarns

Electrically conductive fibers are required for various applications in modern textile technology, e.g., the manufacturing of smart textiles and fiber composite systems with textile-based sensor and actuator systems. According to the state of the art, fine copper wires, carbon rovings, or metallized filament yarns, which offer very good electrical conductivity but low mechanical elongation capabilities, are primarily used for this purpose. However, for applications requiring highly flexible textile structures, as, for example, in the case of wearable smart textiles and fiber elastomer composites, the development of electrically conductive, elastic yarns is of great importance. Therefore, highly stretchable thermoplastic polyurethane (TPU) was compounded with electrically conductive carbon nanotubes (CNTs) and subsequently melt spun. The melt spinning technology had to be modified for the processing of highly viscous TPU–CNT compounds with fill levels of up to 6 wt.% CNT. The optimal configuration was achieved at a CNT content of 5 wt.%, providing an electrical resistance of 110 Ωcm and an elongation at break of 400%.

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

Fine Electrolytic Tough Pitch Copper Multistage Wiredrawing Pass Schedule Design by Analytical and Numerical Methods

Electrolytic tough pitch copper is commonly used in electric and electronic applications while fine copper wires are widely used in electronic conductors. A multi-pass wiredrawing process was designed for the manufacturing of fine pure copper wire, from 0.50 mm to 0.10 mm in diameter. The analytical model and the finite element analysis (FEA) were performed to validate the pass schedule design. The initial wire was mechanically characterized, and the pass schedule design was stablished by the analytical method according to the specific criteria. The sequence of wiredrawing passes was modeled in the finite element method (FEM) software in order to analyze and validate the designed pass schedule. The combination of these methods allowed designing and validating the wiredrawing pass schedule to implement it in a real process with guaranteed results. This work contributes in showing a combined methodology for the design and virtual validation of the pass schedule in the case of multistage wiredrawing of ETP copper fine wires.

RESEARCH OF POSSIBILITY OF USING CHEMICAL METHOD OF FINE METAL PARTICLES REDUCTION FOR BACTERICIDAL SORBENTS PRODUCTION

The present paper is concerned with a research of sorption and bactericidal properties of the fine metal particles applied on the surface of active carbon fabric by chemical sedimentation method. The ascorbic acid and natrium borane were used in the study process as metals, copper and silver reducing agents. Influence of reducer and fine metal nature onto the porous structure, as well as bactericidal and sorption characteristics of obtained fibrous sorbent samples are shown. It is determined that use of ascorbic acid for synthesis of copper and silver fine particles on the active carbon fabrics surface leads to the considerable decrease in a specific surface and volumes of meso - and micropores of the obtained sorbent in comparison with initial active carbon fabric. When using the natrium borane as reducer of fine copper particles the decrease in a specific surface and volumes of sorption pores is also observed. However, when using the natrium borane, the active carbon fabric samples modified with silver particles or with their composition with fine copper particles, had the higher values of porous structure main characteristics in comparison with the initial active carbon fabric. The nature of distribution of fine metal particles at the active carbon fabric surface was investigated by the electronic microscopy method. It was found that during the chemical reduction process the particles of fine copper attached to active carbon fabric fibers, being almost evenly distributed at all surface of fabric. Particles of silver were located as crystal congestions along fibers. Sorption and bactericidal properties of the received samples of modified active carbon fabrics are investigated. Their high sensitivity to microorganism cells which remains during a long storage period is demonstrated. Herewith, the active carbon fabric, modified with particles of fine copper and silver, keeps high sorption properties.