Increasing the Efficiency of Foundry Production by Changing the Technology of Pretreatment with Quartzite

The efficiency of the production of foundry products depends on the reliable operation of the melting furnace including, therefore, the durability of its lining. The most common material adopted for the production of an acid furnace crucible lining is quartzite, in which during the pretreatment (heating to 800 °C followed by holding), a tridymite phase appears that maintains a constant volume at 840–1470 °C for a long time and provides high lining durability of 300–350 melts, but only when using melting temperature regimes not exceeding 1500 °C. However, the absence of iron scrap leads to the smelting of synthetic iron from only one steel scrap using higher melting temperatures (1550–1570 °C), which sharply reduces the lifetime of the lining to 220 melts. This work is devoted to research aimed at establishing technology for the pretreatment with the original quartzite, which ensures the formation of a phase state that successfully withstands elevated temperatures for a long time. The studies were carried out using a Bruker D8 ADVANCE diffractometer and a Shimadzu XRF-1800 X-ray wave-dispersive spectrometer. The work consisted of drying samples of the original quartzite at temperatures of 200 and 800 °C with subsequent exposure to temperatures of 200, 400, 600, 870, 1000, 1200, 1470 and 1550 °C. As a result, the conditions for pretreatment of quartzite were established, during which during its further use, a cristobalite phase can be obtained, which makes it possible manufacture a high-temperature lining that ensures its high durability. The introduction of this technology will ensure the efficiency of the production of foundry products for enterprises operating induction crucible furnaces at industrial frequency.