クエン酸ソーダ溶液による含ニッケルラテライト中のNiおよびFeの溶解性について

Abstract

Experimental studies of the solubilities of nickel and iron in oxidies, hydroxides, laterites and garnieritic ores in the Sodium Dithionite-Citrate solution were carried out to obtain fundamental data on the mineralogical state of nickel and iron in nickeliferous laterite deposits.The solubilites of nickel and iron in artificial reagents increased with leaching time, temperature and the weight of reducing reagents. When leaching time was 10 min, leaching temperature was 70°C and the weight of reagent was 1.0g, the solubilities of nickel and iron reached 95.5%-98.0%.On the basis of the results for the artificial reagents, the solubilities of nickel and iron in laterites and garnieritic nickel ores were also examined with the same method.Used are samples were obtained from both Pulot and Acoje mines in Philippines.The soluble ratios of nickel and iron for Pulot ores in the laterite layer tended to increase with increasing in depth until the layer reached to the upper part of the garnierite layer.Soluble parts of nickel and iron in the are deposit varied in the ranges of 45%-88% and 55%-86%, respectively.The solubilities of nickel and iron for Acoje ores in the laterite layer were very high, showing more than 90 and 95%, respectively. However, the solubilities decreased a little with increases in depth in the laterite layer. These solubility decreases were probably caused by the presence of serpentinite fragments and lack of clayey decomposed serpentinite in the laterite layer.Considering from the data obtained by the Sodium Dithionite-Citrate Method for nickel-iron-hydroxides and heated samples of laterite (Acoje), the solubility difference between the two of ores seemed to be due to the crystability of these constituent minerals.