Purpose. The research aims to develop a technology for tailings solution purification using membrane nanofiltration to reduce waste volume and enterprise costs by reusing the purified water. Methods. The research uses polyamide nanofiltration membranes on a semi-industrial plant. The nanofiltration process is conducted at a pressure of 3.5 MPa with 30% permeate yield. The chemical composition of the solutions is analyzed using atomic-absorption and chemical methods. Findings. Removal of 69% arsenic, 68.5% zinc and 95.7% iron has been achieved under optimal conditions. The purified solution with a residual sulphuric acid concentration of ~3.5 g/l can be used again for leaching lead dust. The concentrated metal solution allows for additional zinc extraction. The use of technology reduces waste volumes by more than 30% and reduces the enterprise’s recycling costs. Originality. The research proposes a new environmentally friendly nanofiltration technology for tailings solution purification that can effectively remove heavy metals and extract valuable components. This approach uniquely integrates membrane nanofiltration at an optimized pressure of 3.5 MPa, achieving high removal rates of heavy metal ions such as As³⁺, AsO4³⁻, Zn²⁺, Fe²⁺, and Fe³⁺, while reducing waste by 30% and enabling the reuse of sulfuric acid and water in the leaching process, leading to significant cost and resource savings. Practical implications. Implementation of the proposed technology at lead dust processing enterprises reduces the costs of wastewater treatment, reduces the waste volume and allows for the reuse of water and acids in the production process.

The sorption, structural, and thermal properties of the interpolymer system based on polymethacrylic acid (PMAA) and poly-4-vinylpyridine (P4VP) were studied at different component ratios for the extraction of rhenium (ReO₄⁻) and molybdenum (${\mathrm{M}\mathrm{o}\mathrm{O}}_4^{2-}$) ions from model solutions. The results showed that sorption efficiency depends on both composition and contact time. Systems with molar ratios of 3:3 and 2:4 exhibited the highest activity, reaching more than 90% extraction for rhenium and up to 94% for molybdenum after 48 h. FTIR spectra indicated the involvement of carboxyl and pyridine groups in complex formation with the metal ions, as evidenced by band shifts and the appearance of new absorption features. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) demonstrated that modification of PMAA with P4VP enhances the thermal stability of the system, which is maintained even after desorption. The system with the optimal composition showed structural stability and the ability to regenerate without a notable decrease in sorption capacity. Sorption performance was preserved across a wide pH interval, with maximum values at pH 2–4, which makes the system suitable for hydrometallurgical applications. Comparison with literature data indicates agreement with current approaches to rare-metal recovery, while the PMAA–P4VP system is distinguished by improved stability and potential for further development. These findings provide a basis for the design of selective and environmentally safe processes for rhenium and molybdenum recovery, relevant to the conditions of the Republic of Kazakhstan, where technogenic solutions rich in these metals are available.

This paper presents the results of studies of intermediate processing for liquid extraction and re-extraction of copper from sulfate solutions obtained during agitation sulfuric acid leaching of lead dusts, which are technogenic wastes of the Zhezkazgan copper smelter and contain valuable components: more than 38 % lead, 2.4 % iron, 3 % zinc, 3.5% copper, 0.7 % arsenic, etc. The utilization of them can provide additional commercial products and improve the ecological environment of the area where they are located. The article also presents the results of the material balance of the processes of liquid extraction and copper re-extraction.

Silicon fouling of strong-base anion-exchange resins reduces the efficiency of uranium recovery from pregnant solutions generated during in situ leaching. This study examined the acid desilication of industrially spent resin using HF and HF–HNO3solutions. The effects of reagent concentration, solid-to-liquid ratio, and treatment time were evaluated. Increasing the HF concentration and the solid-to-liquid ratio enhanced silicon removal. The highest desilication efficiency, 65.5%, was achieved with 2.0 M HNO3 + 0.5 M HF at an S:L ratio of 1:5, reducing the residual Si content to 3.81 wt.%. Most silicon was removed within the first 30–90 min, after which the rate decreased due to intraparticle diffusion limitations. Particle-size analysis showed that the resin beads largely retained their integrity after treatment. The HF–HNO3 system therefore offers a practical approach for regenerating silicon-fouled anion-exchange resins used in uranium hydrometallurgy Кремний қосылыстарымен ластанған күшті негізді анионалмастырғыш шайырлар жерасты шаймалау өнімді ерітінділерінен уранды сорбциялық бөліп алу тиімділігін төмендетеді. Жұмыста өнеркәсіптік пайдаланылған шайырды HF және HF–HNO3 ерітінділерімен қышқылдық десиликациялау зерттелді. Реагенттер концентрациясының, Қ:С қатынасының және өңдеу ұзақтығының әсері бағаланды. HF концентрациясы мен Қ:С қатынасының артуы кремнийдің бөліну дәрежесін жоғарылатты. Ең жоғары десиликация дәрежесі 65,5% 2,0 М HNO3 + 0,5 М HF ерітіндісінде және Қ:С = 1:5 кезінде алынды, ал Si қалдық мөлшері 3,81 мас.% дейін төмендеді. Кремнийдің негізгі бөлігі алғашқы 30–90 мин ішінде жойылды, кейін түйіршік ішіндегі диффузиялық шектеулерге байланысты процесс жылдамдығы төмендеді. Гранулометриялық талдау шайыр түйіршіктерінің тұтастығы сақталғанын көрсетті. HF–HNO3 жүйесін уран гидрометаллургиясында кремниймен ластанған анионалмастырғыш шайырларды регенерациялау үшін қолдануға болады Загрязнение сильноосновных анионообменных смол соединениями кремния снижает эффективность сорбционного извлечения урана из продуктивных растворов подземного выщелачивания. Исследована кислотная десиликация промышленно отработанной смолы растворами HF и HF–HNO3. Оценено влияние концентрации реагентов, соотношения Т:Ж и продолжительности обработки. Увеличение концентрации HF и соотношения Т:Ж повышало степень удаления кремния. Максимальная десиликация 65,5% достигнута при 2,0 М HNO3 + 0,5 М HF и Т:Ж = 1:5; остаточное содержание Si составило 3,81 мас. %. Основное удаление кремния происходило в первые 30–90 мин, после чего скорость снижалась из-за внутригранульных диффузионных ограничений.Гранулометрический анализ подтвердил сохранение целостности гранул. Система HF–HNO3 может использоваться для регенерации кремнезагрязненных анионообменных смол в урановой гидрометаллургии