Modelling the melting of "shaft sludge" from shaft furnace dust removal in a short rotary kiln.

Shaft sludge is a lead-bearing material produced by the wet dedusting of shaft furnace process gases generated during copper smelting from concentrates. It is a material with a high concentration of lead and hydrocarbon compounds, the melting of which in short rotary furnaces causes many problems. This paper presents the results of thermodynamic modelling of the melting process of shaft sludge and other lead-bearing materials. Computations were carried out using HSC Chemistry 8 software by calculating thermodynamic equilibrium by minimising the free enthalpy of the system. Calculations showed that, as a result of the change in technology and the introduction of technical improvements, it is possible to increase the Pb recovery to raw lead from 55.4-70.7%, while maintaining a total Pb recovery of approximately 93%. The calculations presented in the article are realised within the framework of project No. POIR.01.01.01-00-1300/20 - 01 funded by the National Centre for Research and Development, entitled "Environmentally friendly technology for vitrification of lead-bearing slag by intensifying the work of a short rotary furnace with the dust and process gas conditioning system".