The Chusovoi Metallurgical Plant is working constantly to increase the vanadium content of its pig iron. For example, a charge that contained vanadium converter slag was used over an 8-day period in 1964 on blast furnace (BF) No. 1. The average consumption of the slag was 222 kg/ton iron (the chemical composition of the slag and the resulting pig iron are shown in Tables 1 and 2). Thus, the V20 5 content of the furnace slag was increased from 0.14 to 0.35%, while the vanadium distribution coefficient L v = [V]/(V) was decreased from 7.5 to 6.25. The vanadium content of the commercial pig iron remained at the previous level -80.53% (81% in the control period). The pig iron was processed further in accordance with the normal flow chart [ 1 ].In 1987, ash from heating and electric power plants (HPP) was used to increase the vanadium content of the iron. Ash in amounts of 20-30% was added to the charge at the local sinter plant to obtain a special sinter ( Table 1). The percentage of sinter in the charge of 225-m 3 blast furnace No. 1 was varied from 23 to 50% (Table 2). Here, the V205 content of the furnace slag was increased from 0.23 to 0.67%, while the vanadium distribution coefficient L v was raised from 4.5 to 13.4. The losses of vanadium with the top dust were large (2.89--4.60 V205). The iron was shipped to customers as a commercial product [2].In 1997, slag formed at the Nizhniy Tagil Metallurgical Combine (NTMK) in the converter production of steel from vanadium pig iron by the monoprocess [3] was used in the charge of BF No. 2. A distinguishing feature of the converter slag (CVS) is its fairly high contents ofVeO 5 and CaO. The slag also contains 10-12% scrap.Calculations showed that since the Chusovoi plant was also using unfluxed pellets from the Kachkanar Mining-Concentration Combine (KGOK) and since the consumption of raw limestone was thus very high (127 kJton pig), the introduction of CVS would make it possible to significantly reduce the content of flux in the blast-furnace charge: 100 kg of CVS should replace 41 kg of limestone, while a CVS consumption of 100 kg/ton pig was expected to increase the vanadium content of the metal from 0.484 to 0.750%.To check these calculated results, trial heats involving the use of CVS were conducted on BF No. 2 during the period Nov. [13][14][15][16][17][18][19][20] 1997. A CVS consumption of 43 kg/ton pig kept the productivity of the furnace at 1502 tons/day, the adjusted consumptions of coke and flux were reduced by 13 and 8 kg/ton, respectively, and the vanadium content of the pig iron was increased from 0.506 to 0.638% (Table 3). No complications arose in the running of the furnace. The positive results obtained from these heats made it possible to permanently institute the use of CVS in the charge of BF No. 2 beginning in January, 1998.The operating conditions of BF No. 2 improved significantly after it was subjected to a class II overhaul (April-June 1998). In addition, reconstruction of the central trough nearly eliminated the need for slow-speed operation...
The Chusovoi Metallurgical Plant has had a great deal of experience in using vanadium-bearing wastes in metallurgical production. For example, the plant has developed a technology that produces vanadium pig irons with high concentrations of manganese and chromium and that is based on the use of discarded sludge from the production of vanadium pentoxide.As a rule, vanadium-bearing wastes are used in the production of sinter and in the charge of oxygen converters or blast furnaces. However, their use in blast-fumace smelting has an adverse effect on the technology currently employed to convert the given elements (Mn and Cr) and increases the amount of vanadium lost with the furnace slag.Researchers have developed and tested a new method of using wastes and semifinished products (chemical wastes, sludge, top dust, and highly basic vanadium-bearing converter slags) -sintering of these materials, followed by their melting in blast furnaces in a mixture with iron-ore-based materials that do not contain titanium. This method makes it possible to alter the structure of the slag melt and stabilize its properties in the blast-furnace hearth during the smelting of vanadium pig iron. The silicon content of the pig in the trial heats reached 1%, but there were no problems with the running of the furnace or hearth operations. The coefficient characterizing the distribution of vanadium between the pig and the slag increased from 2.3 to 9.5 and the amount of vanadium recovered increased by 5.4%. The content of vanadium pentoxide in the slag decreased from 0.331 to 0.088%, i.e., the irrecoverable losses of vanadium declined by a factor of 3.8.One heat was conducted on a charge consisting of 75% pellets from the Lebedinsk Mining-Concentration Combine and 25% local sinter (sintered from a charge that included 60% vanadium pentoxide). As the control variant, we smelted vanadium pig iron on a charge containing 75% pellets and 25% sinter from the Kachkanar Mining-Concentration Combine. There was no deterioration in the technical-economic indices characterizing the operation of the furnace.The expected change in the structure of the slag melt was realized by comparing the phase composition of the slags in the control period and the trial period. Whereas the slag in the trial period consisted of mellite and the associated phases -mervenite, rankinite, oldhamite, dicalcium silicate, and glass -the mellite-based slag in the control period was fundamentally different -it contained the following related titanium-bearing minerals, % (by vol.): -baikovite Ca2(Mg 3, Ti4+A12 , Ti3+)2(SiO4)2012 -up to 35; -titanavtite m[(CaO MgO 2SiO2)]n(CaO(A1, Ti)203 SiO2] -15-20; -spinel MgA1204 -3-15; -perovskite (CaTiO3) and titanium carbides (TIC) -in small amounts.The use of mathematical models to study heat-and mass-transfer processes in the blast fumace made it possible to establish that there were no significant changes in the heating and reducing potential of the gas from in the different periods ( Fig. 1). However, the change that occurred in the com...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.