Study of rational solution parameters during in-situ uranium leaching

Abstract

Purpose. The research aims to study and optimize the in-situ leaching (ISL) process for uranium mining using surface-active substances (surfactants) to improve the efficiency of uranium extraction from low-permeability ores. Methods. As part of the research, samples of low-permeability ores are taken and previously analyzed for porosity and filtration anisotropy coefficient, which is important for assessing their filtration properties. To study the effect of surfactants such as polyacrylamide, sulfanol and Mesh Drainage Liquid Filter (MDLF) compounds, solutions with different concentrations of these substances are prepared. Also, to determine the most effective surfactant concentrations, additional studies are conducted to optimize the leaching conditions, taking into account the effects of various factors such as temperature and pH of the solution. All the obtained results are mathematically analyzed to identify the optimal conditions, which helps to increase the efficiency of the uranium leaching process and improve the experimental results. Findings. In the course of the research conducted on the selection of surfactants for uranium leaching from low-permeability ores, the following results have been obtained. Sulfanol, as one of the surfactants used, shows the best results, significantly increasing the filtration coefficient from 0.5 to 2.0 m/day. This confirms its high efficiency in improving the ore horizon permeability and in accelerating the leaching process. Originality. The scientific novelty of the research is in the development of methods for optimal use of surface-active substances to improve the efficiency of the in-situ uranium leaching process from low-permeability ores. Studies have been conducted to determine the influence of various surfactants on the filtration properties of ores, as well as their in-fluence on accelerating the leaching process. Practical implications. The practical significance of the research is in the possibility of using the obtained data to optimize the in-situ uranium leaching process at real deposits with low-permeability of ore horizons. The developed recommendations on the selection of surfactants, such as sulfanol and polyacrylamide, as well as their optimal concentrations, can be directly applied to improve leaching efficiency, increase filtration coefficient, and reduce seam treatment time.

English abstract from the paper. The authors’ abstract, reproduced under CC BY 4.0.

Keywords

• in-situ leaching
• filtration coefficient
• porosity
• anisotropy
• colmatation
• sulfanol
• polyacrylamide

In plain English

More than 22 uranium deposits in Uzbekistan are mined by in-situ leaching; the most significant are South and North Bukinai, Uchkuduk, Ketmenchi, Sabyrsai, Sugraly and in-situ leaching site 102. As a deposit is mined, the flow rates of its wells fall, mainly because filters and the rock around them clog. A clay crust from the drilling mud on the well wall has a permeability 4–5 orders of magnitude lower than the rock; chemical and gas clogging develop at the start of mining; and iron hydroxide coats filters, especially in unconfined aquifers when the water level in the well drops below the top of the filter. Clogging by suspended solids in the injected solutions goes on from the start of mining to its end, grows with time and cannot be reversed.

At a low-permeability site of the Ketmenchi deposit, 14 core samples 40 cm long and 90 mm across were taken from the ore horizon and studied at the Central Research Laboratory of NMMC and at the university. Their moisture content was 14–20% and their bulk density 1.18–2.57 g/cm³, rising with moisture. In well No. 3, between 147 and 156 m, uranium in the ore layer was 3.5–6.5 conventional units and carbonate minerals 0.23–2.20%; ferric iron was 0.025–0.19 g/L and Eh 400–480 mV. The ore took on average 37 kg of sulfuric acid per tonne (20–66 kg/t), and aluminium made up 4.8–7.3% of the core. Clogging of filters and of the rock around wells was studied in an experimental block at the Tohumbet deposit.

Of the surfactants tested, sulfanol gave the best result, raising the filtration coefficient from 0.5 to 2.0 m/day; OP-10 raised it to 1.5 m/day, polyacrylamide to 1.0 m/day, MDLF-1 to 0.8 m/day and MDLF-2 to 0.6 m/day. Long use of MDLF-1 caused mechanical clogging of the layer at later stages. Applied at deposits, the methods reduced clogging of the layer by 25–30%. The authors call for pilot tests before the reagents are used at industrial sites.

How to cite

S. Alikulov, J. Toshov, R. Mussin, M. Rabatuly, B. Tolovkhan, Z. Bogzhanova and A. Gabitova (2025). Study of rational solution parameters during in-situ uranium leaching. Mining of Mineral Deposits, vol. 19, no. 1, pp. 37–46. https://doi.org/10.33271/mining19.01.037