Study of the Phase Composition of Spent Quartzite Lining from a Crucible-Type Industrial Frequency Induction Furnace by X-ray methods

Abstract

Results are presented from a study of the phase composition of spent quartzite lining from a crucible-type industrial frequency induction furnace. The study is performed by the methods of x-ray analysis. The lining that was examined contained quartzite, boric acid, and electrocorundum. Different regions of the lining were identified and their phase composition was determined along with the changes in the lattice parameters of the components of each region's phases.Keywords: crucible-type industrial frequency induction furnace (IFC), x-ray phase analysis (XRD), quartzite, layer of the lining.Crucible-type industrial-frequency induction furnaces (IFCs) first began to be frequently used to make cast iron in the USSR at the beginning of the 1970s. In accordance with the requirements of the designers of these furnaces, at the time the cast iron was made from a metallic charge that consisted of foundry iron, conversion iron, factory wastes, the liquid residue in the furnace (1/3 of its capacity), cast-iron scrap, and steel scrap. The scrap comprised 10 -15% of the charge. The temperature at which the melt was formed in the furnace was limited to 1450°C -higher temperatures were not needed for a metallic charge of this type. Also, the temperature just indicated was consistent with the recommendations of the furnaces' manufacturers.Such factories as GAZ, VAZ, and ZIL used Pervouralsk quartzite to make the lining of induction furnaces (models IChT6 -IChT10). The quartzite was first calcined at 800°C for 6 -8 h to dry it and make it more thermally stable. The quartzite was not allowed to have a moisture content greater than 0.3%, so that the design of the foundries of metallurgical plants provided for installation of the equipment needed to meet this requirement. The plans for future foundries were subsequently modified to include equipment which performs the calcining operation needed to dry quartzite. The concept of "synthetic cast iron" then gained currency, this being cast iron made from a metallic cold charge which has a steel scrap content of at least 30%. The production of such cast iron shortened the life of the lining, since it had to function at temperatures up to 1550°C.In Russia, it became impossible to make cast iron on a standard cold charge due to a dearth of scrap iron; the output of foundry iron and conversion iron declined and manufacturers' costs -including transportation costs -rose sharply. As a result, the content of steel scrap in the charge climbed to 70 -80% at many factories. There was a corresponding increase in temperature in the production process, and the durability of the lining began to decrease significantly.The life of the lining is improved by including electrocorundum in its composition. The use of electrocorundum makes the lining more resistant to wear by the melt during operation of the furnace on a cold charge and at high temperatures. The properties of the lining are also affected by the technology used to dry the quartzite. The practice of including quartzite in the lining was based...

Increasing the Efficiency of Synthetic Iron Production by the Use of New Kit Lining

“…The electrocorundum should form an aluminium silicate with a melting point of 1700 • C, which will increase the refractory strength and lining resistance of the material at temperatures above 1450 • C. Additionally, it is possible to form mullite 3Al 2 O 3 • 2SiO 2 (Al 6 Si 2 O 15 ), which increases the fire-and chemical-resistance properties of the acid lining and reduces the penetration of oxide melts in the FeO-MnO-SiO 2 system into a working layer of lining [40][41][42].…”

Specialty of Сarbon-Carbid-Silicic Mixture Using (UKKS) as Substitute of Re-Carburizing Agent and Ferrosilicon for Grey Iron Melting

“…In the total temperature of corium will fall down to 1250-1320C, but it isn't enough, needs 1410-1450C. Because of this, they are forced corium temperature to raise up to 1550-1600C, but it results in a sharp drop of stability acid lining of traditional composition, therefore we need to enter additional additives preserving her stability [1][2][3]. It forces foundry enterprises to approach with big care at a choice of existing materials which it is possible to use as decarburizing and carefully to verify, which is appearing on the market [4][5][6][7].…”