Abstract

An important part of pilot-scale test work, with the intention to design and build an industrial-scale furnace, is the evaluation of refractory materials. Information on wear of the working refractory lining, obtained during excavation of the pilot-scale furnace, can be used to improve designs in future. Therefore, reliable measurement of the wear profile and accurate sampling of refractory materials, are useful methods to apply during furnace excavations. The methods described in this paper, address these requirements. As furnace excavations (both pilot- and industrial-scale) often produce the opportunity to study process materials in more detail, a method of encapsulating a large sample of process material in resin, is also described. 

In 2016 Mintek conducted a pilot-scale study on the production of high carbon ferro-manganese (HCFeMn) using DC-arc furnace technology in sub-merged arc furnace (SAF) mode. The furnace containment system was originally designed for ilmenite smelting trials, conducted in the early 1990’s, and consisted of magnesia-based ramming material installed in the hearth, and magnesia bricks installed in a water-cooled shell as the sidewall-lining. Magnesia-based refractory is not suitable for HCFeMn production, due to the corrosive nature of the slag, and carbon-based working linings are typical for HCFeMn production on industrial-scale. The design of the furnace containment system was therefore adapted to install carbon-based cold ramming paste as working lining in the hearth and lower sidewalls. As back-lining, magnesia-based ramming material in the hearth, and magnesia-based refractory bricks on the sidewall, was retained. Furthermore, the magnesia-based refractory bricks were extended vertically to form the upper sidewall lining.

The furnace steel shell had an internal diameter of 2 470mm. After installation, the lower sidewall had a diameter of 1 700mm in the hearth, and a height of 537 mm. The upper sidewall lining had a height of 570mm and internal diameter of 2 004mm. In the past, manual excavation methods, including wear profiling and sampling, were applied. After the campaign in which HCFeMn was produced, new methods to excavate and sample the burden, to profile refractory wear, and to sample the refractory materials were developed and implemented. The development and implementation of these methods are described in this paper.

The method consists of three sub-sections:


1. Casting of the burden (process material) in resin and excavation of the block of resin encapsulated burden.

2. Three dimensional (3D) scanning of the wear profile of the refractory working lining and superimposing the results onto the model of the refractory design to create a set of detailed drawings.

3. Core drilling samples of the refractory working lining in the hearth.

For each sub-section the method includes sourcing and description of materials used, equipment and detailed steps.