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LURGI's development of the QSL submerged bath smelting technology represented decades of research, pilot testing, and demonstration-scale validation before achieving commercial implementation in primary lead production. This publication documents the comprehensive operating experience gained from the demonstration plant at Berzelius Duisburg and subsequent commercial-scale operation at the Stolberg facility, providing the metallurgical industry with detailed performance data on this transformative direct smelting technology. The progression from demonstration to commercial scale offers valuable insights into technology scaling challenges, process optimization requirements, and long-term operational viability for direct lead smelting.
The Berzelius Duisburg demonstration plant served as the critical proving ground for QSL technology, operating at sufficient scale to validate fundamental process concepts while allowing experimentation with operating parameters, refractory configurations, and process control strategies. Key demonstration objectives included confirming lead recovery rates from sulfide concentrates, validating sulfur capture efficiency and off-gas composition for acid plant integration, assessing refractory wear rates and developing optimal lining systems, and establishing operating protocols for stable continuous operation.
The Stolberg commercial installation represented the full-scale validation of QSL technology, processing substantial tonnages of lead concentrate while meeting environmental standards and achieving acceptable operating economics. Commercial operation confirmed the environmental advantages of direct smelting through elimination of traditional sintering operations with their associated fugitive emissions and difficult-to-control sulfur dioxide releases. Lead bullion quality met market specifications while recovery rates achieved commercial viability.
For metallurgical facilities considering direct smelting technology adoption or seeking to optimize existing installations, this documented progression from demonstration to commercial operation provides essential reference information. Gas Cleaning Technologies' expertise extends to the specialized off-gas handling requirements of direct smelting processes, including accommodation of high-temperature, high-sulfur-dioxide concentration streams and integration with downstream acid production facilities.
