Papers by Keyword: Cobalt

Abstract: This study presents the development of an advanced 215.9 mm drill bit with an optimized material distribution to enhance wear resistance, durability, and operational efficiency in highly abrasive formations. A comprehensive scanning electron microscopy (SEM) analysis of the powders used in the drill bit's construction was conducted using the TESCAN Mira 3 LMU system. The analysis included tungsten carbide–cobalt (WC–Co) and diamond-containing composite powders. The results revealed that WC–Co powders exhibit high density and uniform particle distribution, making them suitable for load-bearing components, while diamond-containing powders ensure superior cutting performance and wear resistance. Based on these findings, a rational material allocation was implemented: WC–Co-based materials were used for structural elements, and diamond-containing powders were applied in cutting and undercutting inserts. Process was optimized to prevent thermal degradation of the polycrystalline diamond compact (PDC) inserts. The developed drill bit was designed for rotary drilling with an axial load range of 20–80 kN, rotation speeds of 80–250 rpm, and a drilling fluid flow rate of up to 40 L/s. The proposed design is particularly suited for the geological and technical conditions of Kazakhstan’s oil and gas fields, contributing to reduced drilling costs and increased efficiency.

Abstract: Lithium-ion battery (LIB) applications in consumer electronics nowdays are rapidly growing resulting the increase of batteries solid waste containing toxic and corrosive substances for the environment. On the other hand, the main active cathode components in LIB are Lithium and Cobalt, which are hazardous and limited in nature but are valuable metals. This study aims to use bio-hydrometallurgical techniques to recover heavy metals from LIB using microorganisms to avoid toxic waste from used solvents which are usually generated in conventional chemical leaching. Filamentous fungi have an important role in secreting citric acid and several organic acids to facilitate the dissolution of metal ions from the metal solids. Self-grown fungi, Aspergillus niger isolated from waste spices (Candlenut) was used as a leaching agent. Route based on fungal activity was evaluated to optimized the detoxification and metal recovery from spent LIB in various conditions (one-step, two-step and spent medium bioleaching) in 21 days of incubation. The quantitative result of XRF and EDX analysis of battery powder before and after bioleaching confirm that fungal activities are quite effective. The maximum recovery of both metals (Cobalt and Lithium) in leached liquor reached up to 72% analyzed using ICP-OES with the one-step leaching method. With respect due to the high metal recovery, fungal leaching has proven to be an easy and cost-effective green metallurgical method for recycling heavy metals in used LIBs.

Abstract: The introduction of antimicrobial nanoparticles into nanofiber coatings is significant for enhancing microbial corrosion protection. Here, electrospun polysulfone nanofiber (PSU-Nf) and PSU-Nf functionalized with biogenic silver nanoparticles (AgNPs) coatings (PSU-Nf-AgNPs) used for Cobalt (Co) corrosion resistance in a marine environment containing Aeromonas eucrenophila (A. eucrenophila). We utilized the barrier function of the PSU-Nf and the bacterial inhibition property of the AgNPs that are synthesized using bacteria. The thickness of nanofiber coatings was 233.11 ± 33.64 µm analyzed by optical microscope and beadless morphology of nanofibers was observed using scanning electron microscope (SEM). The corrosion behavior of Co coated with PSU-Nf and PSU-Nf-AgNPs in abiotic and in the presence of the bacterium environment was investigated via polarization techniques and electrochemical impedance spectroscopy (EIS). Corrosion analysis reveals that the charge transfer resistance (R_ct) increased because of the addition of the nanostructure resulting in a reduction in corrosion rate. SEM micrographs show Co surface was severely damaged by a microbial corrosive attack with severe crevices. However, the PSU-Nf and especially PSU-Nf-AgNPs coated Co surface was still covered by nanofiber coatings as the bacteria colony was not noticed. In addition, the results of the performing bacterial disk diffusion method indicated that electrospun PSU-Nf-AgNPs have good antibacterial activity against Gram-positive, Gram-negative, and model biofilm bacterium. It was found that the uncoated Co surface had severe crevices and offered poor corrosion resistance under mineral salt medium with A. eucrenophila strain. Therefore, PSU-Nf-AgNPs coated Co exhibited better corrosion resistance in mineral salt medium containing bacteria.

Abstract: This paper is dedicated to the investigation of selective copper extraction from the black mass of lithium-ion batteries (LIBs) using ammonium sulfate. Thermodynamic analysis performed with the use of Pourbaix diagrams allowed to compare and predict the area of stable copper and cobalt ammine complexes, determine operating pH range (8.7-9.7) for solutions. Concentrations of sodium hydroxide and ammonium sulfate were defined experimentally allowing to achieve high copper extraction (82-87 %) at low cobalt recovery into solutions (0.25-0.52 %). By variation of main leaching parameters optimal process conditions were determined: (NH₄)₂SO₄ 45 g/dm³, NaOH 9 g/dm³, 25 С, l : s = 5 : 1, 120 minutes.

Abstract: The ultra-dispersive powders of pre-ceramic precursors for boron carbide based composites were obtained by relatively low-temperature (at 200 – 1000 °C) synthesis from liquid charges containing available compounds such as salts and oxides. Boron carbide matrix ceramics were compacted by their reactive spark plasma sintering (SPS) at 1500 – 1700 °C. It is noted that the X-ray diffraction (XRD) peaks corresponding (m)ZrO₂ and WC phases presented in the synthetic pre-ceramic precursors disappear after the SPS is conducted at 1500 °C. It is established that the addition of tungsten and cobalt compounds promotes both the low-temperature synthesis of ceramic components and sintering processes of their powders. Energy dispersive X-ray (EDX) analysis showed that the ceramics contain a small amount of Co (0.8 – 2 wt.%). The density of samples of cobalt-containing ceramics B₄C–ZrB₂–W₂B₅–Co is higher compared to that of cobalt-free ceramics B₄C–ZrB₂–W₂B₅.

Abstract: The sintering at (1.35x103) °C for 90 minutes under argon gas atmosphere formed a nickel aluminide NiAl-based composite strengthened with yttrium oxide Y₂O₃ with the addition of cobalt in the current sample. (ASTM E140 – 12b) was used to perform the Brinell hardness test. The addition of cobalt increases the hardness of the (NiAl-Y₂O₃) composite. The hardness of NiAl-30Y₂O₃ composite improved from 341HB to 359HB after 1.5 wt.% Co was added, although the hardness improved to (381-383)HB after 2-2.5 percent Co was added. According to the findings of the wear examination, the inclusion of cobalt decreases the wear intensity of NiAl-30Y₂O₃, according to the findings of the wear examination. The adhesion wear rate reduces from 7.61 * 10^-6 gr / cm to 6.72 * 10^-6 gr / cm when 1.5 wt. percent Co is added, thus inserting 2-2.5 wt. percent Co reduces the rate to 5.87* 10^-6 – 5.22* 10^-6 gr /cm.

Abstract: The paper provides an assessment of the safety processes of high-modulus energy sources systems during the initiation of flat and cylindrical high-modulus energy sources. The expressions, which establish the relationship between the parameters of flat and hollow cylindrical charges of explosives under the only condition of equality of the developed pressure pulse on the surface of the charge of explosives, provided all other things being equal, were obtained. In contrast to the earlier studies, which assert the existence of a direct relationship between the parameters during the initiation of flat and cylindrical surfaces, the current study demonstrates energy consumption during the initiation of cylindrical surfaces is higher than the initiation of flat surfaces, all other things being equal.

Abstract: The work is devoted to studying of possibility to manufacture cast ball valves of sucker rod oil pumps instead of those manufactured by the powder metallurgy method from Stellite 20 alloy. It is shown that Stellite 20 cast alloy includes about 20% μ and σ brittle phases, destruction whereof, in case of impact-abrasion wear, when excavating oil, leads to quick failure of the valve pair. A new cast cobalt alloy not containing brittle phases has been developed instead of Stellite 20 alloy, which allowed to improve wear resistance of cast valve pairs to the level of valves produced by the powder metallurgy method.

Abstract: Currently, there are practiced various pyrometallurgical, hydrometallurgical, and com-bined pyro and hydrometallurgical methods for processing of oxidized nickel ores to produce metal-lic nickel, cobalt, and their compounds in non-ferrous metallurgy. The problem is the difficult ore concentration, and consequently the high consumption of reagents or low extraction of valuable components from it. Ural plants previously implemented the technology of reducing-sulphiding smelting of laterite ore to produce fire nickel and transfer of cobalt to matte. The economic ineffi-ciency of this technology predetermined the search for a new method for processing of significant reserves of oxidized nickel ores in the Ural region.

Abstract: A systematic study of the adsorption of benzotriazole on Co surface and its removal in aqueous solutions was carried out for post-CMP cleaning application. Static etch rate (SER) measurements and electrochemical impedance spectroscopy (EIS) were employed. The experimental results show that BTA adsorbed well on Co surface when it exposed to BTA solution at neutral and alkaline pH. BTA did not adsorb due to active Co dissolution at acidic pH. The effect of dissolved oxygen (DO) concentration in de-ionized (DI) water on the removal of Co-BTA complex layer was investigated. At DI water rinse process after BTA treatment, Co-BTA layer was maintained on Co surface when DO concentration of DI water was low. Interestingly, BTA was removed by DI water with high DO concentration.