The development of safe and ecologically clean systems for handling radioactive wastes predetermines the sustained stability of geoecocenology.The measures adopted in the nuclear power industry for improving the safety of nuclear power plants have produced conditions for developing nuclear power in the future. The Kola Peninsula lies in a territory of active use of atomic energy, which results in accumulation of liquid and solid radioactive wastes, requiring processing and utilization, in the Murmansk region. These problems can and must be effectively solved taking account of the specific nature of the region. The Kola region is rich in mineral resources and wastes from mining, which can serve as material for producing and obtaining cheap sorption-active and self-hardening compositions for storing radioactive substances.Experience in preparing and handling radioactive wastes at nuclear power plants and other industrial plants associated with radioactive substances has shown that the most promising methods of immobilization and storage of liquid wastes is sorption on a solid-state adsorbent, sealing of the spent adsorbents in concrete blocks followed by vitrification and storage in underground or underwater repositories [1][2][3][4][5]. The subsequent arrangement of the spent adsorbents, elimination of contact with the surrounding medium or storage, impose definite requirements on the adsorbents: the radionuelides must form with the adsorbent matrix insoluble stable compounds which guarantee that the adsorbents are radioehemically stable in the immobilization medium without secondary contamination; the technical products must be convenient for subsequent operations: it must be possible to produce parts and blocks and to ensure shielding from radionnclides contained in the blocks formed; the adsorbents must be cheap and the technology must be simple. In turn, stringent requirements are imposed on the solidifying compositions (binder materials), which in geological formations contain the spent adsorbents: stability of binders with respect to mineralizing solutions and brines in a wide range of pH and ell; resistance to disintegration; low micro-and mesoporosity; closeness of the chemical and mineral compositions to that of the surrounding rock; low coefficient of diffusion of ground-water components in the binder medium; ability to strengthen the structure of the binder as a result of interaction of its components with the components of the geological immobilization medium; and, radiation resistance of the mineral forms of the binder. These requirements can be met by synthesizing technological materials using the technology of solidifying mineral dispersions (SMD materials) based on polymineral alumosilicate raw material [6][7][8][9]. These materials are based on the concept of synthesis of coagulation-condensation solidification structures in highly concentrated mineral dispersions. A highly concentrated mineral dispersion is a multiphase system containing a dispersed phase and a dispersion medium, which can intera...
A method for obtaining sorption-active materials based on a solidifying mineral dispersion composed of nepheline, hydrochloric acid, and water was suggested. The hardening processes and conditions under which sorption-active compounds are formed were studied. The mechanism of sorption of F ! ions on the sorbents developed was determined.A topical environmental problem of the Kola region is purification of mine water and underground water to remove fluoride ions. All the methods presently used for this purpose can be divided into two groups:(1) coprecipitation and coagulation on freshly synthesized aluminum and magnesium hydroxides and calcium phosphate and (2) ion exchange of fluorineselective ion exchangers, e.g., activated aluminum oxide, which is a strongly basic anion exchanger. However, use of these expensive ways to defluorinate water is unacceptable in the case of large-tonnage wastes. Defluorination of sewage from mining plants require granulated sorbents, which can be used by creating check dams before discharging, e.g., mine water into natural water basins. To solve this problem, it is suggested to prepare sorption-active materials by the technology of self-hardening binder systems. By binders (self-hardening) are understood systems containing, in certain relative amounts, the solid and liquid phases that can interact to give new condensed phases and are capable of hardening [1,2]. It is known that condensed reaction products formed in hardening of water-containing binder systems, with aluminosilicates used as a solid phase, are salts of complex composition. These salts contain oxyhydrates, hydrosilicates, and hydroaluminates, which exhibit sorption properties under certain conditions [5].In development of sorbents for defluorination of wastewater, the mineral phase of the self-hardening binder system should be composed of acid-nonresistant aluminum-containing minerals that can interact with aqueous solutions of acids to give hydroxo compounds of aluminum, which are anion-active sorbents under certain conditions [4]. The search for starting raw materials was limited to the natural resources of the Kola Peninsula. Preference was given to nepheline-containing raw materials, whose advantage over other types of raw materials consists in larger resources, fast decomposition by acids, and high content of alumina (up to 30 wt % Al 2 O 3 ). In view of the fact that aluminum hydroxides exhibiting the highest activity toward fluoride ions are formed in hydrolysis of its oxychlorides [4], a hydrochloric acid solution was chosen as the second component of the binder system for synthesis of a fluorine-selective sorbent.The aim of this study was to find conditions under which granulated sorption-active materials to be used in treatment of mine wastewater can be formed by the binder technology in the system constituted by nepheline, hydrochloric acid, and water and to determine the optimal application conditions of the materials obtained.We used a nepheleine concentrate produced by the Apatit Open Joint-Stock Company,...
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