[en] The collection comprises of articles of the staff of Nuclear and Radiation Safety Agency and V.I. Nikitin Institute of Chemistry, Academy of Sciences of the Republic of Tajikistan which were presented on seminars '2011 year - International year of Chemistry' and 'Radiation Safety of Tajikistan'. The collection is designed for scientific, technical and engineering employees working in radiation safety, mineral raw materials processing and hydrogen chemistry.

[en] Present article is devoted to precipitation of ammonium diuranate. The diagram of yellow cake obtaining with using of Ca O was presented. The process of yellow cake obtaining was described. The flowsheet of uranium extraction by sulfuric acid was proposed.

[en] Present article is devoted to decomposition of danburite of Ak-Arkhar Deposit of Tajikistan by hydrochloric acid. The interaction of boron containing ores of Ak-Arkhar Deposit of Tajikistan with mineral acids, including hydrochloric acid was studied. The optimal conditions of extraction of valuable components from danburite composition were determined. The chemical composition of danburite of Ak-Arkhar Deposit was determined as well. The kinetics of decomposition of calcined danburite by hydrochloric acid was studied. The apparent activation energy of the process of danburite decomposition by hydrochloric acid was calculated.

[en] Present article is devoted to chlorination of danburite of Ak-Arkhar Deposit of Tajikistan with a mixture of chlorine gas and sulfur chlorides. The low-temperature chlorination of initial danburite was studied. In order to study the danburite chlorination was used the mixture of chlorine gas and sulfur chlorides with further drying by concentrated sulfuric acid. The influence of temperature and process duration on danburite chlorination was considered. The optimal conditions of danburite chlorination with a mixture of chlorine gas and sulfur chlorides were proposed.

[en] Present article is devoted to nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit of Tajikistan. The obtaining of boric acid from pre backed danburite concentrate by decomposition of nitric acid was studied. The chemical composition of danburite concentrate was determined. The laboratory study of danburite leaching by nitric acid was conducted. The influence of temperature, process duration, nitric acid concentration on nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit was studied as well. The optimal conditions of nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit, including temperature, process duration, nitric acid concentration and particle size were proposed.

[en] Present article is devoted to physicochemical aspects of uranium migration in the system drain waters-soil. The complex investigations of radio-ecological situation of northern part of Tajikistan were carried out. The pathways of uranium migration on the territory of Tailing dump 12 of Taboshar city in the system drain waters-soil were studied. The low and high uranium mobility were determined. The kinetics of uranium sorption by hematite and pyrolusite was defined. It was found that uranium sorption by hematite at high temperature ranges and in alkaline medium is significantly higher than in acid medium and at low temperature ranges.pyrolusite

[en] Present article is devoted to sulfuric acid decomposition of argillite and kaolin clays of Zidda and Chashma-Sang Deposits of Tajikistan. The thermolysis processes of initial and calcined argillite was studied at 100-1000 deg C temperature range. The influence of temperature, process duration and concentration of sulfuric acid on extraction rate of aluminium and iron oxides from calcined ores was studied as well. The optimal conditions of sulfuric acid decomposition of argillite and kaolin clays of Zidda and Chashma-Sang Deposits of Tajikistan, including temperature, process duration, sulfuric acid concentration and particle size were proposed.

[en] Present article is devoted to development of radiation safety in Tajikistan. The history of formation of the Nuclear and Radiation Safety Agency of the Academy of Sciences of the Republic of Tajikistan was presented. The main goals and objectives of Nuclear and Radiation Safety Agency of the Republic of Tajikistan, including regulation in radiation safety, scientific researches in nuclear and radiation safety, radionuclide monitoring of biosphere of Tajikistan, complex processing of uranium ores and wastes, development of laws, regulations and requirements in radiation safety were considered.

[en] Present article is devoted to thermal stability and thermodynamic characteristics of dehydration process of crystalline hydrate of uranyl sulfate and thorium nitrate. The thermal stability of UO_2SO_4·3H_2O and Th(NO_3)_4·5H_2O was studied. Thermodynamic characteristics of UO_2SO_4·3H_2O and Th(NO_3)_4·5H_2O were determined. It was defined that barogram of UO_2SO_4·3H_2O consists of three stages.

[en] Present article is devoted to chlorination of danburite concentrate of Ak-Arkhar Deposit of Tajikistan. The low-temperature chlorination of initial danburite was studied. In order to study the danburite concentrate chlorination was used a chlorine gas with further drying by concentrated sulfuric acid. The influence of temperature and process duration on danburite concentrate chlorination was studied as well. The optimal conditions of danburite concentrate chlorination were proposed.