Slag cleaning

An installation of this type was installed at the Umicor Hoboken smelter in Belgium (Van Negen, Maes and Cocklebergs, 1990). In that operation 20 per cent of the charge was cold slag and reported operating data is as follows  

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Slag Cleaning J Fuming Not Aoplicabie Not Applicable Not Applicable... 

This process requires two or three distinct steps depending on whether a final slag cleaning step for complete base metal recovery is required. The steps for single and two furnace operation are ... 

D. Robertson and S. Kang, "Model Studies of Heat Transfer and Flow in Slag-Cleaning Furnaces," Fluid Flow Phenomena in Metals Processing, (1999), 157-168. 

S. Kang, "A Model Study of Heat Transfer and Fluid Flow in Slag-Cleaning Furnaces," Dissertation Abstracts International (USA), vol. 52, (1992), 1-182. 

The model contains two types of furnaces continuously operated furnaces like the flash furnace and semi-batch operated furnaces as such as the Slag Cleaning furnace and the anode furnace. The continuously operated furnace is fed material for smelting unless the furnace is offline, no feed is available and the furnace is below the maximum operating level. Tapping occurs when a minimum level of material is in the furnace - although there needs to be an available pot and/or furnace to tap into. 

The Outokumpu smelter operates in very much the same way as the Kiveet process. However, it consists of two separate furnaces, one for smelting and the other for electric slag cleaning. Between them is a short launder, through which directly reduced lead bullion and lead oxide slag flow continuously. The lead bullion can be separately tapped from the flash furnace, if required. 

Defect found only in the mixed (electrode+wire) technique, it presents itself in the slab as an elongated, cracked inclusion of a certain thickness, usually positioned on one side of the bevel. It is caused by bad slag cleaning in the second bead, which remains imprisoned and does not melt in the successive wire bead. 

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