SPECIFICATION OF MgO-CONCENTRATE OBTAINED FROM POST MORTEM MgO-C REFRACTORY MATERIALS

Abstract

The recycling process of post mortem MgO-C (MC) materials is based on carbon removal from the crushed material. The laboratory results of the annealing of the crushed post-mortem MC bricks in a static layer, in an air atmosphere in an electric furnace are presented. The quantity and quality of the fractions size was evaluated before and after annealing. The results show that the carbon inside the grains of size 6.3-15 mm is incompletely burnt out under the given conditions. The results from annealing of the fractions size below 6.3 mm confirmed that the carbon burning out decreases the strength and density of the agglomerates, which then partially disintegrate during annealing. A mechanical load is needed for the complete disintegration of the brittle agglomerates. In addition, the results of the MgO-fractions quality evaluation are discussed, which were obtained by annealing the grit from the post-mortem MC bricks from the pilot-plant experiment in a rotary kiln in the factory Hačava, from the company INTOCAST Slovakia a.s.. The obtained fraction size of MgO possesses a suitable chemical and phase composition. However, the strength of the MgO-grains core was lower. This confirms that the post-mortem MC materials may be recycled; however, it requires waste management and the related technical equipment for the recycling processes.

Magnesia‐carbon refractories from recycled materials

“…The recyclate exhibited comparable chemical and phase purity to virgin MgO raw materials, but the strength of the MgO grains was reduced. 9 MgO recyclates, made from recycled MgO-C with final oxidizing thermal treatment, were successfully used to produce MgO 10 and MgO-C 11 refractories. The recyclate content was up to 30% and up to 53%, respectively.…”