No abstract

Recent interest in the use of uranium as an alloying agent for steel has made it desirable for the metallurgical analyst to familiarize himself with the analytical chemistry of this 'element. This circular summarizes the chemical properties of uranium and reviews current literature for its separation and determination. Typical analytical procedures, illustrating the best-known methods for the separation and determination, and using standard analytical equipment and techniques, are presented. In addition, x-ray and radiometric methods, capable of providing analytical results within a few minutes, are described. The extensive references should be useful in developing new analytical procedures to deal with unusual problems.

The preparation and characterization of a set of six ores of the naturally radioactive elements, for use as certified reference materials in chemical and radiometric analysis, is described. The set consists of two series representing Canada's original uranium-producing areas--Elliot Lake in Ontario and Beaverlodge in Saskatchewan. The Elliot Lake series comprises two samples, one of ore and the other of waste-grade material, both of whichcontain uranium and thorium. The second series consists of essentially thorium-free material from Beaverlodge, covering the rangeof 0.02% to The former is intended as a reference material for chemical determination of uranium and thorium, while the latter may also be employed in calibrating and verifying radiometric surveying and assaying equipment. In addition to their uranium and thorium contents, supplementary information as to mineralogical composition, state of radioactive equilibrium, and composition with respect to most common and many trace elements of significance in ore processing is given. The recommended values for uranium in DH-1, DL-1, BL-1, BL-2, BL-3, and BL-4 aie respectively: 0.177%, 0.0041%, 0.022%, 0.453%, 1.02% and 0.173%; recommended values for thorium in DH-1, DL-1 and BL-1 are respectively: 0.104%, 83 ppm (83 lig/g) and 15 ppm (15 pg/g).

A colorimetric procedure is described for the determination of the total cyanide content of effluents from gold cyanidation plants and of water from basins into which they discharge. The method has several advantages over the official American Water Works Association Methods for routine mill use. First, the colour reagent is stable and easily prepared. Second, the initial colour development, which takes only 25 minutes, provides a visual indication as to whether the cyanide content exceeds 0.5 ppm and hence permits a quick screening-out of high-level samples. Determinations on samples with lower cyanide content can then be completed within an additional 45 minutes by a simple solvent extraction-spectrophotometric step. Actual working time is of the order of 20 minutes per sample and, since equipment requirements are minimal, a high throughput is possible. The method determines cyanide present as hydrocyanic acid, cyanide ion, zincocyanide, cuprocyanide and nickelocyanide, but not cyanide present in the form of ferrocyanide or cobalticyanide. It is free from interference by thiocyanate or cyanate and other common constituents of gold-mill effluents. It is also unaffected by the Products resulting from the decomposition of cyanide by hypochlorite; and, by means of an addition of sodium arsenite to the sample, the interfering effect of hypochlorite itself can be eliminated. It can therefore be used as a means of following the progress of the hypochlorite process for the destruction of cyanide.

Enviromental research related to uranium tailings is being carried out within the Mining Research Laboratories and Mineral Sciences Laboratories of CANMET, EMR. Field-related research on uranium tailings has been conducted at Elliot Lake for over five years. Much of the work has been focused on a program to rehabilitate pyritic tailings. This has resulted in developing a practicable technology for growing vegetation on such wastes. Limitations have been samll size of the est-plots and the relatively short period during which experiments have been carried out. A research program aimed at identifying and reducing acidic and radioactive effluents is also underway at Elliot Lake. These liquid effluents have been identified as the most serious threat to the enviroment. Research at the Mineral Scicence Laboratories and its predecessor divisions relating to the processing of uranium and thorium ores is outlined. A process has been developed for recovering thorium which could reduce the overall radioactive load in the tailings. Much of the current work is related to developing new technology for recovering uranium from lower-grade ores which, however, is unlikely to be implemented within the next ten years. A significant effort is also being made in removing pyrite, preconcentrating radioactive materials, and identifying and removing chemical compounds that carry radium in solid tailings. All of these investigations could have an impact on near-term solutions to some enviromental problems. Mineral Sciences Laboratories has the analytic capacity to identify and characterize both mineralogical and most radiochemical constituents of the Elliot Lake ores.