Aim. The aim of the study is to develop technologies for processing geothermal brine produced with the extraction of oil as well as to solve environmental problems in the region.Methods. In order to determine the chemical composition and radioactivity of the geothermal water and solid samples, we used atomic absorption and gamma spectrometry. Evaluation of the effectiveness of the technology was made on the basis of experimental studies.Results. In the geothermal water, eight radionuclides were recognized and quantified with the activity of 87 ± 5 Bq / dm3. For the processing of this water to produce lithium carbonate and other components we propose a technological scheme, which provides a step of water purification from radio-nuclides. As a result of aeration and alkalinization, we can observe deactivation and purification of the geothermal water from mechanical impurities, iron ions, hydrogen carbonates and organic substances. Water treatment allows recovering lithium carbonate, magnesite caustic powder and salt from geothermal water. The mother liquors produced during manufacturing operations meet the requirements for the water suitable for waterflooding of oil reservoirs and can be injected for maintaining the reservoir pressure of the deposits.Conclusion. The implementation of the proposed processing technology of mineralized geothermal water produced with the extraction of oil in the Northern Dagestan will contribute to extend the life of the oil fields and improve the environmental problems. It will also allow import substitution in Russia for lithium carbonate and edible salt
