Monometer has continued to develop rotary furnace equipment for the recovery of tin from tin drosses and scrap materials. The most recent installation was installed and commissioned in China in Autumn 2008.
The tin content in the charge materials is within the region of 75% - 80%, with the remainder being made up of caustic cake and other materials including estimated minimum 4% moisture content. A typical overall recovery in excess of 95% metal from the metal bearing content of the materials initially charged into the furnace is achieved in the Monometer rotary furnace.
The new installation in China smelts up to 400-kg of charge materials. Reductant and other additive quantities were established and the fuel consumption was approximately 80 litres diesel oil per hour (equivalent to about 85 cub metres Natural Gas per hour).
The Rotary Furnace can also be run continuously to process between 2 and 3 tonnes of Ash in a single cycle. This procedure involves back-charging and part-tapping for short periods of about 20-seconds to discharge up to 100-kg of tin metal from time to time. The advantages of continuous operation with part-tapping and back charging are
- Losses due to fuming are reduced because the liquid tin is removed from the furnace soon after it has been formed.
- The furnace is kept near full capacity which reduces losses and reduces the effective tin loss to the slag.
The process with best results utilises the slag recycling and baghouse dust recycling similar to that used in lead smelting and other similar smelting processes. The return of slag and baghouse dust to the furnace typically achieves an overall recovery in excess of 95% metal from the metal bearing content of the materials initially charged into the furnace.
After-burner equipment is not required with this process; since there are no dioxins, furans, and other combustible products escaping from the furnace exhaust system.
Monometer manufacture a full range of Rotary, Reverberatory, and Crucible melting furnaces as well as electrically heated box and continuous process Mesh Belt furnaces for Heat Treatment applications.