论文部分内容阅读
本文研究了用EDTA及酒石酸作掩蔽剂,以磷酸盐沉淀六价铀(对低品位样品采用Ti~(4+)作共沉淀剂)而达到铀与其他干扰元素分离的目的。用12—15%H_2SO_4溶解NH_4UO_2PO_4沉淀后,以硫酸亚钛作还原剂,将六价铀还原到四价。加入CU~(2+)溶液控制Ti~(3+)的用量,用Hg(ClO_4)_2或Hg(NO_3)_2溶液消除由过量Ti~(3+)所还原而析出的金属铜沉淀。最后,在二苯胺磺酸钠(或苯基隣氨基苯甲酸)指示剂存在下,用重铬酸钾或钒酸铵标准溶液滴定至微紫色,即示终点。本方法有较高的精密度(标准偏差0.02—0.06%)。与连二硫酸盐-磷酸盐-重铬酸盐(或钒酸盐)容量法比较,二者的准确度基本上是一致的(相对偏差0.11—0.52%),但本方法具有适应范围广、速度快以及还原剂(Ti~(3+))不会放出有害气体影响工作人员的身体健康等优点。含铀量测定范围为1—100毫克,因此不论是低品位矿石(可测低至0.03%的品位),或是浓缩物、金属铀等高含量的试样均适应。
In this paper, we studied the separation of uranium from other interfering elements by using EDTA and tartaric acid as masking agents and phosphate precipitation of hexavalent uranium (Ti ~ (4+) as coprecipitating agent for low-grade samples). After the precipitation of NH_4UO_2PO_4 with 12-15% H_2SO_4, the hexavalent uranium was reduced to tetravalent with titanium sulfate as reducing agent. The amount of Ti ~ (3 +) was controlled by adding CU ~ (2+) solution, and the precipitation of metal copper precipitated by excess Ti ~ (3 +) solution was eliminated by using Hg (ClO_4) _2 or Hg (NO_3) _2 solution. Finally, sodium diphenylamine sulfonate (or phenyl anthranilic acid) indicator in the presence of potassium dichromate or ammonium vanadate standard solution titrated to slightly purple, which shows the end point. The method has higher precision (standard deviation of 0.02-0.06%). The accuracy of the two methods was basically the same (relative deviation 0.11-0.52%) compared with that of the dithionate-phosphate-dichromate (or vanadate) method. However, this method has the advantages of wide adaptability, Speed and reducing agent (Ti ~ (3+)) will not emit harmful gases affect the health of staff and other advantages. Uranium content in the range of 1-100 mg, so whether it is low-grade ore (measurable down to 0.03% grade), or concentrate, uranium and other high-content samples are to adapt.