Basel Convention
Environmentally Sound Management of Lead-acid Batteries in the Caribbean and
Central America
Technical Report 1 – MetaloXsa, Santa Domingo,
Prepared by: Brian Wilson, ILMC Program Manager
- Tilting Rotary Furnaces
As promised here are some photographs of front loading and front tapping Rotary furnaces.
The first photograph shows a tilting Rotary furnace with a fixed front hygiene hood and hinged ceramic filled door. As the whole furnace can tilt forward there is no need for front tap holes and the metal and slag will pour front the front doorway as shown. Please note in particular that the door is designed with a wide channel at the top to fit exactly into the extraction ducting and ensure that all the excess furnaces gases are extracted and ventilated to the baghouse. You can see the burner hole in the center of the door and just see the burner located behind the door.
Fig. 1 – Titling Rotary Furnace – Front Tapping
Fig. 2 – Titling Rotary Furnace – Showing Hydraulic Tilt Mechanism
- Inert Secondary Residues
During the visit we discussed the requirements for the production of an Environmentally friendly slag (residue). I mentioned that continued use of soda ash without the introduction of new computerized furnace controls would result in the continued production of unstable water-soluble toxic slags. I also mentioned that the use of calcium salts as fluxing agents, whilst desirable because they produce stable inert slags, was uneconomical due to the increased wear on the refractory lining resulting from the higher furnace temperatures required to smelt with Calcium salts.
If you wish to continue to use Rotary furnace technology to smelt the scrap battery material I think that you have two choices, namely the Kaldo Furnace technology marketed by Boliden Contec or the “Green Slag” technology marketed by Lead Metal Technologies. Both technologies are environmentally sound and are summarized below:
- Kaldo Furnace
The Kaldo furnace is manufactured and marketed by the Swedish Mining Company Boliden Se. The Kaldo furnace tilting technology incorporates oxygen flame enrichment to reduce smelting cycle times. The oxygen rich flame also lowers the back pressure on the furnace enabling a reduction in the ventilation requirements.
The technology can be scaled to suit the expected material throughput and has eliminated the use of soda-based fluxes so that an inert stable slag is produced. The furnace would still have the versatility to process plates, paste, residues and oxide production waste.
The Kaldo furnace
- Green Slag” Process
Lead Metal Technologies (LMT) offers a process that will enable the production of stable inert slags using a Rotary Furnace and Soda Ash flux. The procedure is currently being operated at three Mexican based operations, one of which I visitedin Monterrey at the Inertec Recycling plant.
The process includes a new slag casting system that dramatically decreases slag solidification time and avoids movement and storage of molten slag molds. Furthermore the process package includes a water and effluent treatment plant that will meet US EPA liquid effluent discharge standards.
Please do not hesitate to contact me if you have any queries or if you would like to contact either LMT or Boliden Contech.
Brian Wilson
ILMC Program Manager