Postmortem Study of a Magnesia-Chromite Brick from a Lead Recycling Furnace

Abstract

This study provides an example of a detailed postmortem analysis carried out on a used silicate-bonded magnesia-chromite brick out of a lead recycling furnace. The magnesia-chromite brick suffered from a high chemical attack due to the process slag. The high CaO, BaO, and sulfur-bearing silicate slag, as well as a high Na 2 O supply from soda resulted not only in a deep-reaching infiltration of the brick microstructure but also in a severe corrosion of the brick components. Both the sintered magnesia and chromite were attacked chemically. The FactSage calculations showed the formation of high amounts of liquid phase in the infiltrated microstructure and the formation of various Na-Ca-Al-silicates. A detailed investigation of the wear mechanisms through ''postmortem studies'' is a crucial prerequisite for every refractory producer to understand the interactions between slag and refractory materials. The obtained information and insights serve as a basis for improving refractory materials (i.e., choice of refractories for individual process and new developments) and consequently furnace operations (i.e., prolonged furnace campaigns).

Innovative Methodology for Comprehensive Utilization of Spent MgO-Cr2O3 Bricks: Copper Flotation

“…In the recent decades, a number of studies have been conducted to solve the problems brought by spent MgO-Cr 2 O 3 bricks. Improving refractory life and developing new chrome-free refractories have nowadays received much attention as potential methods to reduce the amount of spent MgO-Cr 2 O 3 bricks and to avoid chromium pollution, respectively. , Although the lifetime of the refractory can be improved by optimizing the lining concept, engineering the slag, and changing the process conditions, , and thus substantially reducing the amount of the waste, it is unable to fundamentally solve the problems. A variety of chrome-free refractories, such as magnesia-alumina, magnesia-carbon, and alumino-silicate materials, − have been successfully developed and applied to iron metallurgy and refractory linings for rotary kilns in the cement industry, but in many secondary metallurgy processes in ferrous metallurgy as well as in the metallurgy of copper and lead, MgO-Cr 2 O 3 bricks are still used on a large scale because of their outstanding performances compared with these chrome-free alternatives. , A more sustainable method to solve the problem is to recycle spent refractories.…”