Staged Improvement of Technological Efficiency in FeSi75 Production in a Six-Electrode Submerged Arc Furnace

Sławomir Kozłowski, Radosław Miśkiewicz, Wojciech Bialik, Stanisław Gil, and Tomasz Kraszewski

DOI: https://doi.org/10.64486/m.65.4.12
Online publication date: April 17, 2026

Abstract: The production of high-silicon alloys in submerged arc furnaces (SAFs) is among the most energy-intensive processes in ferroalloy metallurgy. This paper reports a staged improvement of technological efficiency during industrial FeSi75 production in a six-electrode SAF. Performance was assessed using daily productivity, specific electricity consumption, and stability of silicon content in the product. The analysis used daily production records (electricity and product mass aggregated over 24 h; chemical composition calculated as a mass-weighted average of product containers). Shutdown and start-up days were excluded using current- and pow-er-based criteria. In 2020, the structure of carbon reductants was modified, which coincided with a decrease in specific electricity consumption by approximately 120 kWh/Mg relative to 2016–2019. In 2023, the bath depth was reduced from 2500 mm to 2200 mm, and the operating point was intensified (active power from 5.7 MW to 6.1 MW; electrode current from 28 kA to 31 kA), resulting in a further reduction in specific electricity consumption and an increase in daily productivity. Throughout the analysed period, the silicon content remained stable at about 75 wt. % Si. In the investigated stage, the power-supply system (transformers and short network) was not modernised, indicating that measurable KPI improvements can be achieved through process- and construction-side actions and operating-regime optimisation under industrial constraints.

Keywords: ferrosilicon; FeSi75; submerged arc furnace (SAF); six-electrode furnace; specific electricity consumption; productivity; carbon reductants

This article is published online first and will appear in Metalurgija, Vol. 65, Issue 4 (2026).