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Zircon is the main opacier in the ceramic sector, however its high cost limits its wide use and has led to the search of alternative materials. Nowadays, industrial whitening agents with dierent chemical formulas have started to be used in engobe, glaze and body compositions instead of zircon, to reduce raw material cost. Therefore, the purpose of this study is to investigate the possibility of usage of dierent industrial whitening agents as an alternative to zircon in opaque frit compositions. It was shown that, all of the studied whitening agents decreased the sintering and softening temperatures of the wall tile glazes. Although, alumina based whitening agents caused a glaze with transparent and boiling appearance, alumina with zircon and silica based whitening agents caused glazes with semi-opaque and glossy appearance. Even though none of the studied glazes has reached the standard whiteness indice, results suggest that alumina with zircon and silica based whitening agents could be a good candidate for zircon substitution in opaque frit compositions.