Dowa Steadily Raises TSL Furnace Operating Rate at Kosaka

A TSL (top submerged lance) furnace, newly introduced in Kosaka Smelting & Refining, Akita, Japan, is steadily raising its operating rate. Kosaka Smelting & Refining is a nonferrous metal smelting subsidiary of Dowa Holdings. The furnace’s operating rate was 64% at monthly average in fiscal 2009 (April 2009-March 2010). In fiscal 2010, the operating rate keeps 70-80% and achieved 71% of initial target. Dowa Holdings will increase recycling metal items and keep stable operation of the furnace.

A TSL furnace can utilize various metal scrap, such as printed circuit board even containing precious metals, or hard-to-use ores as smelting materials. Dowa started commercial operation of the furnace in April 2008. The firm replaced a conventional flash furnace with a TSL furnace to diversify metal scrap usages.

Dowa has improved the TSL furnace’s melting process and realized higher operating rate. The firm now aims to increase recycling metal items. The firm had recycled 17 metals with the previous flash furnace including gold, silver, copper, lead, bismuth and tellurium. The TSL furnace can recycle tin and nickel in addition to these 17 metals.

Dowa plans to introduce nickel collecting facilities and start the operation within fiscal 2010. The firm also schedules construction of tin collecting facilities and expansion of bismuth collecting facilities. The furnace is even able to collect rhenium, one of rarest metals.

Dowa also tries to keep stable operation of the furnace regardless of using various scrap items. For instance, contained metals are different by makers and applications for used printed circuit boards. Such a kind of scrap causes unstable furnace operation. The firm seeks more flexible recycling capacity to improve the furnace’s operating rate.