Abstract

MOHALE, G.T.M. et al. SEM image processing as an alternative method to determine chromite pre-reduction. J. S. Afr. Inst. Min. Metall. [online]. 2017, vol.117, n.11, pp.1045-1052. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/2017/v117n11a9.

The specific energy consumption (SEC) of the pelletized chromite prereduction process is the lowest of all FeCr production processes commercially applied. This process also eliminates the use of chromite ore fines that could result in furnace blow-outs or so-called bed turnovers, yields a high chromium (Cr) recovery, and can produce a low-sulphur (S) and -silicon (Si) FeCr. However, this process requires extensive operational control due to the variation in pre-reduction levels and carbon contents of the pre-reduced, pelletized furnace feed material. The wet chemical analytical method currently applied for the determination of chromite pre-reduction is time-consuming. In this paper, the development of an alternative method consisting of scanning electron microscopy (SEM) micrograph image processing is presented. A strong linear correlation (R² = 0.919) between chromite pre-reduction (%), as determined by wet chemical analysis, and the new method was obtained. Further development could result in the industrial application of the method, which could contribute significantly to the metallurgical stability and enhanced process control of the pelletized chromite pre-reduction process.

Keywords : chromite pre-reduction; solid-state reduction of chromite; scanning electron microscopy (SEM); image processing; metallurgical carbon balance.

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