No abstract

Existing traditional uranium mining technologies have major drawbacks, do not meet the requirements of a market economy, are ineffective, require the use of a large number of expensive injection and pumping wells, low leaching rates, require a large consumption of chemical reagent, sulfuric acid (to produce 1 ton of uranium concentrate requires a flow of 100 tons sulfuric acid). Here, a productive solution refers to a chemical solution containing the concentration of the leached therein of various useful components (metals), including uranium, dissolved therein. In the practice of exploitation of hydrogenous uranium deposits, the arrangement of technological wells has been adopted: linear (or in-line), areal (or cellular) and combined. Our proposed innovative technology for the exploitation of hydrogenous uranium deposits will be developed on the principle of piston wells using the effect of activation of a chemical solution supplied to the array of a hydrogenated uranium layer for leaching and other useful components. In the process of activation, the chemical solution is heated to t = 70 ° C, the water in the solution becomes a good solvent. Pumping wells are used as piston wells without changing the design, i.e. pumping wells are also used as injection wells. This article presents the mining and geological characteristics of technogenic uranium deposits in Kazakhstan. The basis of the raw material base of Kazakhstan's uranium is exogenous type deposits, combined into a subgroup called “infiltration”. Uranium infiltration deposits are formed by groundwater associated with regional formation zones and zones of soil-layer oxidation. The development and implementation of the method of underground well leaching of uranium (UWL) is one of the most important scientific and technical achievements of the mining industry. The main advantages of the underground leaching method compared to traditional mining methods of developing deposits are as follows: the possibility of involving poor and off-balance ores in deposits with complex geological and hydrogeological conditions, but with large reserves of uranium; Significant reduction in capital investments and terms of commissioning deposits; improving working conditions, reducing the number of miners and increasing labor productivity by 2.5-3.5 times; reducing the negative impact of uranium mining on the environ-ment.

No abstract

В статье авторы рассматривают физико-химические свойства нанозолота, содержащегося в рудах и минералах. Ими описаны наиболее важные физико-химические свойства нанозолота. Показаны различные формы существования наноча- стиц золота. У наночастицы размером 2 нм около 60% всех атомов составляют поверхностные атомы золота с неском- пенсированной валентностью. Более мелкие наночастицы золота имеют электронное окружение и способны активно осуществлять каталитические реакции. Обсуждены и показаны коллоиды, золи и мицеллы золота. Охарактеризованы химические катализаторы, сформированные на основе наночастиц золота.

Introduction. At present, in the instrumental study of the mineral forms of finding gold in geogenic and technogenic ores, more and more attention has been paid to free gold, with a size of several nanometers. Such gold has been found in almost all types of its geogenic ores: starting with deposits of primary sulfide ores and ending with various gold-bearing placers. A similar situation is observed with technogenic gold-bearing ores accumulated in numerous dumps and tailings. At the same time, with the increase in research on nanogold, not only its fundamental, but also practical importance grows, because. in theoretical and applied research, more and more of its actual physical and chemical properties and previously unknown phenomena and effects accompanying them are discovered and clarified. Research methods and materials. An important aspect is the instrumental study of the geometry of various forms of nanogold occurrence in natural (geogenic) and technogenic ores and minerals. The instrumental and analytical part of our research was based on the visualization of nanoparticles obtained from the Nanjing Research Institute of the Chemical Industry under Sinopec (PRC), carried out on a JEOL 2010F microscope. Research results. The studied gold nanoparticles were presented in the form: • spherical fullerene-like monoparticles; • fullerene-like gold cells, consisting of a different number (from 13 to 20 clusters) of gold nanoparticles; • self-organized «fractal» dendrites; • rather complex composites with the participation of nanogold; • various aggregates of nanoparticles, etc. The concentrations of gold nanoparticles vary significantly from one deposit to another and between individual ore facies (even within the same deposit). Discussion of the obtained results. It was found that nanogold can be contained in arsenopyrites in 2 main forms: a) as a structurally bound solid solution (Au + 1) located in the lattice of this mineral; b) in separate mineral inclusions of submicron size or nanoparticles. Gold nanoparticles (5-10 nm in size) detected in arsenopyrite in concentrations up to 4% mass fraction are sufficiently representative to account for their amount in gold-bearing ores. A gold nanoparticle with a size of 3 nm usually has an average coordination number CN = 9.5, similar nanoparticles with a size of 1 nm have an average CN = 6, and nanoparticles with a size of 0.5–1 nm have an average CN = 3.6. Conclusion. To date, a nanoparticle catalyst has been developed in which gold clusters are attached to metal oxides that are semiconductors. At the same time, their number is very limited and includes only Fe2O3, TiO2, CeO2, and MgO compounds, which can be used not only in the form of nanoparticles, but also nanofilms. Such an innovative nanocatalyst ensures the efficient flow of a number of oxidative and other processes with hydrocarbons at normal temperatures, which is difficult to achieve by other methods. Findings. The article presents the results of studies of the physicochemical properties of gold nanoparticles installed in ores and catalysts. The morphology of gold nanoparticles has been established. The character of gold speciation in various sulfides is determined. The presence of gold nanoparticles in ores and rocks in the state of colloids has been confirmed. The catalytic activity of nanoparticles of various shapes and chemical states was revealed, depending on the values of the ambient temperature. The results of the research can be useful in the enrichment of gold-bearing ores of upland deposits.