Uranium Wastes Treatment
Developing Technological Basis for Wastes Reprocessing of Uranium Industry in Tajikistan
Tech Area / Field
- ENV-RWT/Radioactive Waste Treatment/Environment
8 Project completed
Senior Project Manager
Genisaretskaya S V
Nuclear and Radiation Safety Agency (NRSA), Tajikistan, Dushanbe
- Institute of Chemistry named after V.I.Nikitin, Academy of Sciences, Republic of Tajikistan, Tajikistan, Dushanbe
- ALLDECO.CZ.a.s., Czechia, Hodonin
Project summaryThe purpose of the project is to develop principal technological schemes for wastes reprocessing of uranium industry of for extraction of uranium protoxide-oxide (U3O8). On the territory of the Republic of Tajikistan there are wastes of uranium industry in the amount of 55 million tons. There is no any development on reprocessing of these wastes, which can be used for extraction of U3O8 – valuable raw for atomic power engineering.
The project is directed on creation of conditions for re-orientation of scientists, which are involved in the development of materials of for military industry and their involvement for solving problems, connected with development of the processing technologies for mineral ores and industrial wastes.
The present project is dedicated to physical and chemical study of uranium wastes reprocessing process in Tajikistan.
It is necessary to mention that the problem of radiation protection in Tajikistan – is one of the branches of global ecological problems, since in the territory of 6 regions of Sogd oblast which are located not far from settlements the huge amounts of uranium-containing ores wastes of high intensity are accumulated. It is accumulated in squares as well. Besides these wastes are located not far from Syr-Darya river which supplies the Republics of Central Asia with water.
In this connection the treatment with accumulated wastes becomes actual issue – relocation, disposal, control over uranium tailing dumps conditions, and their maintenance in satisfied engineer and geological condition. Thus, during the last years in view of ecological risk of uranium industry dumps, field of investigations on their impact to the environment and economical practicability of their second reprocessing in order to extract uranium are appeared. For this purpose detailed developmental work is required which is connected not only with uranium extraction but at the same time with relocation of wastes to more safe uranium tailing dump.
In the present project the task of physical and chemical process study of uranium extraction from dumps and technology investigation of second waste reprocessing in uranium industry is raised.
Possibilities of dumps reprocessing will be studied and schematic technological diagram on use of uranium wastes will be developed.
Optimal parameters of uranium wastes opening will be identified; experimental and technological tests will be realized including operations on leaching, filtration, ammonia precipitation of uranium; glowing of urinate.
Engineer and geological condition of disposed and suspended uranium tailing dumps will be studied.
Practical significance of the project is to develop technological scheme for reprocessing of “rich” and “poor” wastes due to availability of nitrates and ferric sulfate in old dumps, possibilities of dumps opening without use of oxidizing agents. “Poor” sands can be used on the stage of uranium opening by sulfuric acid. Preliminary economical calculation showed that the effect from introducing these recommended schemes at reprocessing of 1,2 million tons of dumps and extraction of approximately 1200 tons uranium protoxide-oxide can be estimated as 1 149 280, 00 $ US dollars.
What kind of threats from uranium tailing dumps:
- The objects are in seism-dangerous zone
- Objects arranged in the basin of Sir-Darya river.
- Have become mudflows
- Fixed 4 happens washing out of tailing pits in Taboshar and Adrasman districts.
Main information about tailing dumps:
At the present moment in the territory of the Republic of Tajikistan there are more than 22 tailing dumps and dumps rocks, which contain radioactive elements, presenting potential threat for the republic population and neighboring countries. These tailing dumps with the bulk over 210mln. tons wastes and 54,8mln.tons of which are radioactive. They are located in 10 tailing dumps and covering 170 hectares with the total activity 6,5 thousand curies.
CHKALOVSK CITY. Maps 1-9, located in 1,5 km distance from residential settlement. It was operated in 1949-1967yy. The total area is 18 hectares, Quantity of wastes 3 million tons. Сoating thickness by neutral ground is 0,5 – 0,7 m. MED on the surface is till 16-35 microroentgen/hour. Disposal is needed.
Dump of stulms 1,2,2 of former mine 3, in 4,5 km distance from residential settlement located down on the slope in the foothills of Mogoltau mountains. It was operated in 1976-1985yy.The total area is 5,9 hectares. The quantity of wastes is 0,35 million tons. Сoating thickness by neutral ground is 0,5 – 0,7 m. MED on the surface is till 30-60 microroentgen/hour. Carrying out of drilling and blasting operations on stulms is required in order to prevent access of unauthorized persons. Natural gamma-background is about 45 microroentgen/hour
TABOSHAR CITY. Tailing dump of former workshop № 3, which is located in 1 km distance from residential settlement. It was operated in 1949-1965 yy. The area is 2,9 hectares, quantity of wastes is 1,2 million tons. Сoating thickness by neutral ground is 0,7-1,0 m. MED on the surface is till 40-60 microroentgen/hour. Disposal is needed. Tailing dumps of I-IY line are located in 1,5-2 km distance from residential settlement. In case of emergency situation, the wash-out of radioactive materials is possible in all tailing dumps of Taboshar city down on the Utkonsu river up to Sirdarya river. In operation was: I-II lines – 1945-1959 yy. III lines – 1947-1963 yy. IY line – 1949-1965 yy. Total area 54,5 hectares, the quantity of wastes 7,6 million tons. Сoating thickness by neutral ground is 0,7 – 1 m. MED on the surface is 40-70 microroentgen/hour. Disposal is needed.
ADRASMAN SETTLEMENT. Tailing dump №2, which is located in the west part of settlement. It was established in 1991 after carrying out the recultivation works in the area. The area is 2,5 hectares. The quantity of wastes is 0,4 million tons. Covered by big-fragmental material. MED is 40-60 microroentgen/hour. Natural gamma-background is about 45 microroentgen/hour. In case of emergency situation, the wash-out of radioactive materials is possible along Karamazar river with the fall into Syrdarya river
BASE ORE PLANT. Tabashar-city. Dumps of base ore plant, mine 6 and stulms 4, are located in 2 km distance from residential settlement are not covered. The constant wash-out of radioactive materials takes place. The wind and erosion overrunning down on the Sarimsahli river with the fall of material into Utkonsu river and further down till the Syrdarya river. It was operated in 1950-1965 yy. The area is 3,6 hectares. The quantity of wastes is 2,2 million tons. MED on the surface till 300-500 microroentgen/hour. Carrying out the design and survey works for disposal of wastes is required.
GAFUROV CITY. According to exploratory survey, a decision was taken to bury the tailing dumps on its location. After realization of this actions the radiation environment at the tailing dumps characterized by the following data: Maximum equivalent dose of gamma radiation is within the limits of 12-15 microroentgen/hour, radon emission does not exceed 0,04 Bqм2/second which corresponds to natural background. Long term control is carried out since 1992 year. Evaluation of engineer and technical condition of tailing dumps is carried out annually. Gamma radiation and emission of radon are measuring. Natural gamma-background is about 15 microroentgen/hour
DIGMAI TAILIG DUMP. Digmay tailing dump is operating now. It is full for 80% and that's why its preservation is unpractical. That's why we organized long-term control over tailing pit condition and its influence on natural environment of adjacent territory.Gamma-radiation on the surface is within the limits of 600-800 microroentgen/hour. Emission of radon is assessed as 120 curie/year. Contour of radioactive contamination is defined in result of ground gamma survey within protected sanitary zone. Vegetation map is constructed in result of botanic and bio-chemical investigations in 1991, control profiles for further measurement are chosen. The contour of groundwater contamination is defined in result of electro-profiling by method of vertically-electric sounding and direction of contaminating elements migration from tailing pit is defined. These kinds of works are repeated in 1994-2005 years.
In order to implement the set tasks it is planned to solve the following problems:
- Mineralogical and chemical tasks, connected with investigation of phase and physical and chemical composition and properties of uranium wastes by methods of physical and chemical analysis;
- Kinetico-chemical tasks, connected with investigation of uranium wastes against temperature, composition, concentration, dispersibility and other factors during acid and thermal treatment;
- Experimental-industrial and technological tasks, connected with determination of optimal kinetic and thermodynamic parameters of processes for determination of material and thermal balance, selection and justification of apparatus and equipment for carrying out experimental-industrial tests of the developed principal technological schemes of wastes reprocessing of uranium industry.
We regularly exchange information with collaborator on progress made, jointly will use separate equipment; samples obtained during the substance reaction will be provided for tests.
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