Vol 60, No 7 (2017)

Six samples of G coal characterized by different vitrinite reflection coefficient (R_o,r = 0.64–0.74%) are investigated. With increase in R_o,r, the plastic-layer thickness y increases from 7 to 17 mm, the free-swelling index SI from 0.5 to 3.5, and the Roga index RI from 1 to 21. The temperature range of plasticity expands from 34 to 94°C. The results clarify the difference in clinkering properties of the gas coal.

The components of the coal batch supplied to Kuznetskaya enrichment facility and OUOU EZSMK are studied experimentally, along with the other concentrates used in coking at AO Evraz ZSMK and other Kuznets Basin concentrates. On the basis of models of the concentrates available at Kuznetskaya enrichment facility and OUOU EZSMK, with different rank composition and properties simulating production conditions, various production batches for AO Evraz ZSMK are formulated and undergo laboratory coking. In addition, several production batches at AO Evraz ZSMK containing other Kuznets Basin concentrates are also studied. The maintenance of the required CSR/CRI ratio of the coke with variation in the coal available at Kuznetskaya enrichment facility and OUOU EZSMK is discussed.

Attention focuses on the structure and electrical conductivity of carbon materials obtained by the carbonization of coal pitch in the presence of additives (nanotubes, graphite foam, and graphite), at temperatures up to 900°C. In some cases, ultrasonic mixing is used on introducing the additives to the pitch. Ultrasonic mixing is found to change the properties of the pitch and affect the properties of the carbon material produced. In particular, the proportion of carbon with an ordered structure is increased; the electrical conductivity at temperatures below 40 K is increased; and the energy barrier E_g between individual crystallites is reduced almost fourfold. At higher temperatures, the electrical conductivity is practically unchanged. Adding nanotubes to the pitch reduces the content of ordered carbon structures in the carbon material produced and lowers its electrical conductivity. Adding graphite foam and graphite to the pitch increases the order and electrical conductivity of the carbon material produced and lowers the energy barrier E_g between individual crystallites in the samples. The electrical conductivity of all the carbon materials below 16 K is described by the characteristic formula for fluctuation-induced tunneling conduction. This indicates that contacts between individual crystallites are mainly responsible for the electrical conductivity.

The introduction of wastewater purification of nitrification–denitrification type in coke production at Visakhapatnam Steel Plant involves reconstruction of the existing biochemical system and the construction of additional units. That permits compliance with the standards for most pollutants. The results of introducing the new process are described, and the basic problems of biochemical water treatment before and after reconstruction are noted.

The basic principles for the reconstruction of sectional cooling towers are considered on the basis of current information technology. In reconstruction, a group of cooling microtowers is installed on a special reference grid. The air parameters that must be monitored so as to permit automatic control of the reconstructed tower are noted. This approach improves the energy efficiency of the evaporative cooling of circulating water at industrial enterprises and reduces pollution emissions to the surroundings with the discharged steam.