Properties of synthetic graphite from boric acid-added pitch: performance as anode in lithium-ion batteries

Synthetic graphite is produced by a heat treatment process using a carbon precursor (pitch, coke), but it is difficult to produce synthetic graphite of high quality due to the high-temperature process (minimum 3000 °C). Elements used as additive to lower temperature the graphitic process include boron, phosphorus, and nitrogen. Boron is known as a graphitization additive, because it accelerates the homogeneous continuous graphitization process of the entire carbon without any formation of specific carbon components such as graphite. In this study, various amounts of boron and PFO (pyrolysis fuel oil, carbon precursor) were used in an attempt to reveal the boron additive effect. Pitch was produced using a boric acid and pyrolysis fuel oil (PFO), and high-temperature carbonization was carried out at 2600 °C. As a result, synthetic graphite exhibiting high crystallinity at a relatively low temperature was produced. The electrochemical performance of several boron-doped and non-doped carbon materials with different structures as anodes in lithium-ion batteries was investigated by a structure analysis.

The Study of Destructible Annealed Anode Paste in the Current CO2

The article is devoted to the study of destructibility of the annealed anode paste of different composition in the CO2 current. It is shown that the destructibility of CO2 current of petroleum coke is much less than that of pitch coke. The comparison of the qualitative characteristics of the anode paste on the basis of pitch coke and petroleum coke revealed the advantage of petroleum coke, due to its low sodium content. The average destructibility of the anode paste on the basis of different grades of cokes in the CO2 current is determined. The conducted semi-industrial tests were in good agreement with the laboratory studies.

Properties dependence of the lightweight alumina products obtained by a semi-dry pressing method on the alumina type

Lightweight materials are widely used in industry for thermal insulation of various thermal units. The choice of lightweight material depends on the specific conditions of service. For the lining of high-temperature units operating in reducing environments, alumina lightweight products are used that contain a minimum amount of Fe2O3 impurities and free (unbound in compounds) SiO2. In JSC “URIR named after A. S. Berezhnoy” a technology of alumina lightweight products of grades KLA-1.1 and KLA-1.3 by a semi-dry pressing method with an application temperature of up to 1550 °C has been developed. These products are made from a mixture of ground and no-milled γ-form alumina of grade 0 and α-form alumina of grade S with additives of pitch coke and chalk. The work purpose was improvement of the alumina lightweight products technology and search for new alternative raw materials along with the currently used alumina grade S. The properties dependence of alumina lightweight products, obtained by the semi-dry pressing method, on the type of alumina α-form, was investigated. As a result of the studies, it was found that, for the manufacture of alumina lightweight products of grades KLA-1.1 and KLA-1.3 by the semi-dry pressing method, alumina grades N and NR can be used as an alternative alumina-containing raw material along with alumina grade S. The phase composition of alumina lightweight products of grades KLA-1.1 and KLA-1.3, which are manufactured using alumina grades S, N and NR, was represented mainly by corundum and calcium hexaluminate. The alumina lightweight products, which were manufactured using alumina grades S, N and NR, were characterized by similar high properties and correspond the technical requirements for grades KLA-1.1 and KLA-1.3.

Study on the properties of coal-based high-purity graphite

As one of the major value-added products of coal processing and utilization, coal pitch coke and coal tar pitch are used as raw materials to prepare high-purity graphite. The structure characteristics and properties were measured by experiments. The results show that the high-purity graphite has excellent physical properties: the skeletal density of 1.81–1.91 g/cm3, the Shore hardness of 45.5–66.6 Hs, the flexural strength of 33.0–46.1 MPa, the compressive strength of 65.6–75.8 MPa, the ash content of 67–181 ppm, the thermal expansion coefficient of 3.71–4.11 × 10–6/°C, and the electrical resistivity of 8.72–12.13 μΩ · m. Consequently, coal-based graphite materials have excellent properties and good application prospects in solar energy industry, which is an effective exploration for the transformation and upgrading of Chinese coal industry.