Sukinda overburden is dumped with chromite ore tailing which contains about 17% Cr₂O₃. The other constituent with overburden is iron, silica and alumina. Because of its complex nature and large amount of gangue material it is not suitable for the extraction of valuable chromium by conventional route. The author of the present investigation has tried to recover chromium as sodium chromate from chromite overburden. In this investigation the ore is mixed with sodium carbonate. The mixture is heated in a raising hearth furnace at 1123 K. Before roasting, TG/DTA analysis has been done to fix the operating temperature. After roasting at 90 min, the roasted product is ground and sieved. The rate-determining step of roasting for the conversion into sodium chromate has also been investigated and it shows that the required activation energy at the temperature range 923–1123 K is 60 kJ/mole. The roasted product is leached in hot water condition at an optimum pulp density of 1:5 to obtain the chromium recovery. After leaching, solid liquid separation is done. The leach liquor containing sodium chromate is vaporized and a bright yellow crystal of sodium chromate is obtained. A recovery of 85% chromium is obtained at the optimum condition and the purity of sodium chromate is found to be 99.5%. This chromate is suitable for the use in chemical and tanning industries. A portion of ore, roasted product and leached residue are subjected to XRD and EPMA studies to know the mode of conversion and phases present in different stages of reaction.

Sukinda 覆盖层倾倒铬铁矿尾矿，其中 Cr ₂ O ₃含量约为 17%. 具有覆盖层的另一种成分是铁、二氧化硅和氧化铝。由于其性质复杂，脉石物质多，不适合常规途径提取有价铬。本次调查的作者试图从铬铁矿覆盖层中以铬酸钠的形式回收铬。在这项调查中，矿石与碳酸钠混合。混合物在 1123 K 的升底炉中加热。在焙烧之前，已进行 TG/DTA 分析以固定操作温度。烘烤 90 分钟后，将烘烤过的产品研磨并过筛。还研究了焙烧转化为铬酸钠的速率决定步骤，结果表明在 923-1123 K 温度范围内所需的活化能为 60 kJ/mol。焙烧后的产品在热水条件下以1:5的最佳矿浆密度浸出以获得铬回收率。浸出后进行固液分离。将含有铬酸钠的浸出液蒸发，得到亮黄色铬酸钠晶体。在最佳条件下铬的回收率为85%，铬酸钠的纯度为99.5%。这种铬酸盐适用于化学和制革工业。对一部分矿石、焙烧产品和浸出渣进行 XRD 和 EPMA 研究，以了解转化模式和不同反应阶段中存在的相。将含有铬酸钠的浸出液蒸发，得到亮黄色的铬酸钠晶体。在最佳条件下铬的回收率为85%，铬酸钠的纯度为99.5%。这种铬酸盐适用于化学和制革工业。对一部分矿石、焙烧产品和浸出渣进行 XRD 和 EPMA 研究，以了解转化模式和不同反应阶段中存在的相。将含有铬酸钠的浸出液蒸发，得到亮黄色铬酸钠晶体。在最佳条件下铬的回收率为85%，铬酸钠的纯度为99.5%。这种铬酸盐适用于化学和制革工业。对一部分矿石、焙烧产品和浸出渣进行 XRD 和 EPMA 研究，以了解转化模式和不同反应阶段中存在的相。