Abstract:
In this work various conditions to extract chromium from titanium dioxide surface using acid and alkali reagent were studied. The effect of type of reagents, concentration of reagents, solid-liquid ratio and perchloric effect were investigated. Acid reagents used in this work were sulfuric acid and nitric acid. Alkali reagent was sodium dioxide solution. It was found that chromium extraction with acid reagents provided higher recovery efficiency than that using alkali reagent. With 5 molarity of sulfuric acid and 1:50 of solid-liquid ratio, the maximum achievable percentage (100 percent) of chromium extraction was found. The percentageof chromium extraction were 96 and 68 with nitric acid and sodium hydroxide, respectively. The solid-liquid ratio also plays a major role in extraction of chromium. The extraction of chromium in all experimental conditions increased with the decreasing of solid-liquid ratio. The results also showed that percentage of chromium recovery increased with increasing of nitric concentration. On contrary, this maximum recovery percentage was reduced with rising of sulfuric concentration. Finally, it was found that perchloric acid decreased the chromium extraction efficiency. Resultings from this study might beneficial for extraction of other heavy metals fiom titanium dioxide surface as well.