TBRF - TOP BLOWN ROTARY FURNACE

This technology was initially adopted by the Copper and Nickel industry, and is now a mainstream technology for the recovery, upgrade and refining of Precious Metals and is used widely for:

• Treatment of ashes from gold /silver refining and jewelry manufacturing
• Treatment of copper (non ferrous metals) sludges from precious metals refining
• Treatment of copper smelter anode slimes containing precious metals
• Treatment of electronic/electric scrap as PCB, batteries etc.
• Treatment of photographic waste
• Fuming treatment for elimination of selenium, zinc and numerous other volatile metals
• Melting of copper, copper alloys and other non ferrous metals
• Treatment of Miller Chloride sludges from gold refineries

ADVANTAGES AND MAIN TECHNICAL FEATURES OF TBRF PROCESSING

• Easy loading operations both for batch or continuous use
• Highly efficient process management
• Quick and precise pouring operations
• High heat and mass transfer rates for rapid processing
• Thermal efficiency up to 60 – 70%
• Low gas emissions
• Very efficient recovery of gold from refining/jewelry ashes with only 20-30 g/T of losses
• Simple & quick shell replacing/refurbishing
• Control of furnace atmosphere by burner/lance stoichiometry
• Oxygen-fuel combustion lance (on request also with air-fuel), using either Natural Gas or Propane for intensification of process and reduced process gas emissions
• Inclined angle, about 30° for firing and metallurgical oxygen blowing
• Pivot tilting for movement of port to feeding, firing and pouring stations
• Rapid rotation to mix reagents with fluxes during smelting phases, and to disperse slag and expose metal for oxidation stages
• High wall thickness made by refractory bricks or equivalent material

BASIC TECHNICAL DESCRIPTION OF TBRF

The furnaces with up to 2000 liters of volume are mounted on skids including the electric control panel and the gas ramp.

The vessel consists of a carbon steel flanged cylinder bolted with a carbon steel cone onto the top flange and a thick carbon steel base-plate to the base flange of the vessel. The motorized drive shaft is bolted to the carbon steel base-plate, and located on the tilting frame of the plant.

The vessel is lined with special refractory bricks. The wall thickness of the refractory depends on the size of the furnace with a minimum of 200 mm. The standard rotation speed of the vessel is about 2-10 rpm and the tilting one about 1-2 rpm.

The vessel’s rotation is controlled by a variable speed gear-motor powered with an electric engine controlled by inverter and mechanically fastened to the vessel’s frame. The positioning of the furnace during tilting/pouring movement is totally controlled by rotating encoder and PLC.

The choice of the electric engines instead of the hydraulic ones increased the operational safety in all the working conditions and the precise positioning of the furnace to ensure a perfect separation between slag and metals during pouring operation.

The burner is provided with an oxygen-fuel mixture or with air-fuel capable to reach temperature of about 1500 and

1300°C respectively.

The gas ramp controls the stoichiometry of the flame regulating the perfect ratio of the gases. The electric panel supervises the tilting and rotation speed and movement and the correct functioning of the burner. The burner consists of concentric pipes (ceramic or metallic) with different diameters and it’s mounted on a rotating or fixed hood used also for the evacuation of the fumes.

A local panel (portable of fixed) is used for the control of the operational control of the furnace as tilting and rotation.

TECHNICAL DATA