The use of liquid bath furnaces has shown to be an energy efficient and environmentally friendly way for both the primary and secondary production of non-ferrous metals such as lead, nickel and copper.
Typical for these kinds of furnaces is the injection or generation of reactive gasses which occurs below the surface of the liquefied feed material. The large amount of rising gases during processing can cause foaming of liquid slag, as illustrated in the schematic below.
This slag phase is in most cases present as the upper layer of the liquid bath. The formation of excessive amounts of slag foam can hinder the production and lower the available capacity of existing smelting and converting furnaces. It is thus important to control this phenomenon and keep foaming to a minimum.
It is generally accepted that the formation of slag foam is caused by a combination of a large amount of rising gases and the inherent foam stability of the slag, which in turn depends on the physical properties of the liquid slag. These causes are studied on a fundamental level. Foaming stability is modelled using novel computer simulations, supported by experiments.
The generation of gasses is studied by investigating the behaviour of liquid slags to absorb and release oxygen gasses. These gasses can be absorbed over a large period of time and suddenly be released afterwards which contributes to the large amount of rising gases and thus slag foaming during copper smelting.