Complex utilization of uranium ores

In recent years uranium deposits with rich ores have become almost completely exhausted. At the same time, the demand for uranium is increasing, and therefore poor uranium ores are being exploited. In regard to the profitable treatment of these ores, considerable importance attaches to their complex exploitation with the extraction of other constituents. The complex exploitation of gold-uranium and uranium-vanadium ores is being carried out on an extensive scale, and the problems involved in the recovery of uranium and accompanying constituents from uranium-containing phosphorites, coal and shale, uranium-thorium ores, as well as uranium-copper, uranium-pyritic, zirconium-uranium, niobium-tantalum-uranium and uranium-molybdenum ores are being resolved in a positive manner. The increased interest in the complex exploitation of uranium ores enables some new forms of mineral raw materials to be included in the industrial scope.     

Industrial methods of processing poor uranium ores

In recent years great progress has been achieved in the technology of processing uranium ores. A method of extracting uranium from solutions by means of absorption on resins, developed comparatively recently, now makes it possible to obtain more than 70% of the total extractable uranium. The extraction of uranium with liquid extractants also finds wide application, especially in plants using acid leaching of uranium.The normal methods of mechanical enrichment (gravitation, flotation, etc.) play a comparatively small part. However, with complex and poor ores being used, mechanical enrichment in the processing of uranium ores assumes greater importance. Radiometric enrichment is particularly progressive and this makes use of the radioactivity of uranium minerals for separating them from barren rock.     

Nucleogenic Cl, U and Pu in uranium ores

The nucleogenic isotopes ³⁶Cl, ²³⁶U and ²³⁹Pu are produced naturally in subsurface environments via neutron capture of thermal and epithermal neutrons. Concentrations are, however, very low and accelerator mass spectrometry (AMS) is required for quantitative measurements. A particular challenge is presented by the measurement of ²³⁶U/²³⁸U ratios down to the level of 10⁻¹³ that is expected from rocks with low uranium concentration. Here, we present the AMS methodology that has been developed at the ANU for measuring ²³⁶U/²³⁸U ratios at this level. The more established methodologies for ³⁶Cl and ²³⁹Pu measurements are also summarised. These capabilities are then used to characterize the ³⁶Cl, ²³⁶U and ²³⁹Pu concentrations in a range of uranium ores. A simple model of the neutron production and capture processes in subsurface environments has been developed and is presented. It is shown that nucleogenic ³⁶Cl, ²³⁶U and ²³⁹Pu can be used to determine both thermal and epithermal neutron fluxes in subsurface environments. Potential applications include uranium exploration and monitoring of the environmental impact of uranium mining.     

The use of the isotopic composition of lead for prospecting uranium ores

The article examines the probable causes of the appearance of anomalous leads and the possibility of the use of isotopic anomalies in leads for prospecting uranium deposits. It is assumed that the apperance of leads with an unusually high content of radiogenic isotopes (Pb²⁰⁷, Pb²⁰⁶) is due to the following geological processes: 1) the rapid accumulation of young sediments as a result of the intense erosion of ancient uranium deposits; 2) the assimilation by magma and deep-seated granitization of uranium-bearing rocks which appeared long before magma-tism; 3) hydrothermal metamorphism of uranium ore bodies; 4) supergenesis in the oxidation zone of uranium deposits.     

Measurements of natural concentrations of I in uranium ores by accelerator mass spectrometry

An accelerator mass spectrometry system is described and utilized for measurements of ¹²⁹I concentrations in natural and environmental samples. We report here on measurements of ¹²⁹I isotopic abundances in iodine reagents and in iodine of mineral origin and of ¹²⁹I concentrations in uranium ores of different origins. The ¹²⁹I isotopic abundances for two measured contemporary iodine reagents and for iodine from a deep underground brine are 1.3 × 10⁻¹³ and about 4 × 10⁻¹⁴, respectively. ¹²⁹I/U ratios in the range 10⁻¹³–10⁻¹² are measured and compared to a simple model of ¹²⁹I production by spontaneous and induced fission of uranium. No clear correlation with the uranium concentrations or residence times is observed.     

The provision of radiation safety of personnel in the extraction of uranium ores

The radiation hazard to the respiratory organs of miners in uranium mines is assessed and a set of measures is worked out for ensuring radiation safety in the prospecting and extraction of uranium ores. Measures are described and justified which, as a result of achieving them, enable a standard to be set for a mining atmosphere and also to prevent external radiation overexposure and radioactive contamination of the integumenta of people working in the uranium mines.Translated from Atomnaya Énergiya, Vol. 19, No. 2, pp. 161–168, August, 1965     

An association of pitchblende and selenides in ores of a hydrothermal uranium deposit

The author examines an association of pitohblende and selenides, establishes the sequence of mineral formation,and distinguishes the principal paragenetic associations. Inferences regarding the geochemical conditions of formation of the uranium ores and selenides are drawn from the variations in the paragenetic association's mineral composition.Translated from Atomnaya Énergiya, Vol. 20, No. 1, pp. 46–50, January, 1966     

伟晶花岗岩型铀矿石堆浸工艺研究与应用

介绍某低品位伟晶花岗岩型铀矿石矿物特性。研究在混合氧化剂存在条件下的这种难浸矿石的堆浸工艺。500 t半工业结果表明:试验解决了该类型矿石堆浸工艺,达到了工业生产要求的技术指标。     

矿物中铀、钍、金、钪的堆中子活化分析

中子活化分析具有灵敏度高、选择性好、用样量少、不破坏分析样品,且可进行多元素同时测定等优点,因此适于岩矿样品的分析。 我们利用原子能所实验性重水型反应堆进行辐照,用美国CANBERRA公司生产的SCORPIO-3000系列多道计算机系统,用仪器中子活化分析法测定了岩矿中的铀、钍、金、钪的含量,得到较为满意的结果。 一、实验1.仪器和设备体积为96厘米3的同轴Ge(Li)半导体探测器和4096道脉冲幅度分析器组成的γ谱仪,     

Direct determination of the uranium content in ores from measurements in drilled wells

Ural State Mining-Geological Academy. Translated from Atomnaya énergiya, Vol. 77, No. 2, pp. 159–162, August, 1994     

Determination of the optimum yield of enriched ore in radiometric enrichment of uranium ores

In this article a method is presented for determining the optimum conditions of operation of radiometric ore-sorting plants with allowance for the expenditure on geological prospecting S₁, ore extraction S₂, radiometric enrichment S₃, hydrometallurgical reduction S₄; also taken into account are the ore enrichment yield γ, the uranium content in the ore α, the coefficients of uranium recovery in the radiometric enrichment of the ore ε and hydrometallurgical reduction ε '. In order to determine the minimum cost of uranium salts S_m, an analytical method is used; S_m is represented in the form of a continuous function

$$S_m = F(S_1 ,S_2 ,S_3 ,S_4 ,\alpha ,\gamma , \in \in ').$$     

The conditions of formation and classification of exogenous uranium deposits

Some previously published schemes are given for the classification of exogenous uranium deposits; a brief ctitical review is given of the main principles of the classification; the stages of ore formation are described corresponding to the stages of formation of the ore-containing sedimentary rocks. Finally, a scheme is proposed of a classification which takes into account the conditions of formation and the composition of the ore-containing rocks, and also the dynamics of the ore-forming processes.Translated from Atomnaya Énergiya, Vol. 14, No. 3, pp. 296–308, March, 1963