Vessel integrity aspects in non-ferrous pyrometallurgical reactors.

Vessel integrity is a vital aspect in the production of metals, determining the efficiency and feasibility of pyrometallurgical production processes. The linings in the reactors are made of refractory bricks, ceramic materials used for their excellent chemical and thermo-mechanical properties at the operational temperature. Nevertheless, failure of the lining occurs over time due to a combination of thermal, mechanical and chemical stresses, requiring a timely and costly replacement of the lining. Reducing the refractory wear would lead to less standstills and thus a more cost efficient production process. The objective of this work is to investigate the in-situ formation of phases by reaction with the slag as a method to limit the chemical refractory degradation caused by PbO-SiO2 based slags. The chemical degradation of porous magnesia-chromitebricks by PbO-SiO2 based slags is caused by (1) liquid infiltration into the porous refractory brick and (2) dissolution of MgO from the refractory into this liquid slag. Slag engineering is successfully used to form a protective layer between the liquid and the refractory brick sample,slowing down the dissolution rate as the refractory components have to diffuse through this new layer. For deep infiltration slags, the liquid composition, and thus the chemical corrosion, changes inside the refractory brick and the protective layer no longer forms. The formation of in-situ phases is used to seal off the open pores in the refractory. This has been tested for refractory brick under isothermal conditions and under a temperature gradient. The latter uses a newly designed experimental setup. The ability to seal off the pores before complete infiltration depends on the ratio between the growth rate of the new phases and the infiltration rate of the liquid. 

Keywords:Reactors

Disciplines:Thermodynamics, Materials science and engineering, Ceramic and glass materials, Semiconductor materials, Other materials engineering, Analytical chemistry, Physical chemistry

Project type:PhD project