粘土中难浸铀的研究

STUDY ON LEACHING OF REFRACTORY URANIUM IN CLAY

木文研究了A矿床和其它几个铀矿床中粘土样的铀浸出性能,探讨了粘土中部分铀难浸出的原因。研究结果表明,粘土样中难浸出的铀与粘土矿物(包括蛋白石、针铁矿等)在岩石变质过程中的重结晶作用有关。粘土中难浸铀形成的可能历程是:粘土矿物吸附U^(6+)→U^(6+)还原成U^(4+)→矿物重结晶使U^(4+)处于封闭或半封闭状态。 试验结果表明,要浸出粘土样中难浸出的这部分铀必须使含铀粘土矿物产生新的缺陷,重新打开通向矿物颗粒内部孔隙的通道,从而使处于封闭或半封闭状态的铀暴露出来;同时还必须使U^(4+)氧化成U^(6+)。中低温氧化焙烧、160—180℃加压碱浸、浓酸浸出等是处理这类难浸矿石的有效方法。

The leaching characterises of uranium-bearing clay of depositde A an other uranium diposits are described. The causes of leaching refractoriness of the uranium in clay have been discussed. The research results show that the reason of leaching refractoriness of the uranium in clay is associated with recryctallization of clay minerals (including Opel and goethite) during metamorphism of rocks. The probable course of forming refractory uranium in clay may be. adsorption of U+6 by clay minerals, reduction of U+6 to U+4; recrystallization of the clay minaral and U+4 exists at closed or semi-closed state in it. The results show that in order to lecah the refractory uranium in clay, the uranium-bearing mineral should be made to produce new faultness for reopening the passages into the mineral, thereby the uranium existing at closed or semi-closed state is exposed, and at the same time U+4 is oxidized to U+6. The middle-low temperature oxidation roasting,pressure alkaline leaching (160-180℃), and leaching with concentrated acid are efficient in treating the refractory type uranium ore.