Title: Thermodynamic Eh-pH Windows for the Selective Recovery of Dy, Te, Mo, Cu and Ni from Copper-Smelting Technogenic Solutions
Authors: Khudoymuratov Shukhratjon Jumaboyevich, Kholikulov Doniyor Bakhtiyorovich
Volume: 10
Issue: 7
Pages: 308-312
Publication Date: 2026/07/28
Abstract:
Copper smelting generates several liquid effluents - gas-scrubbing solutions, vitriol-plant mother liquors, and strongly acidic chloride-bearing wastewater - that carry recoverable dysprosium, tellurium, molybdenum, copper and nickel alongside corrosive anions such as chloride and sulfate. This study consolidates thermodynamic potential-pH (Eh-pH) modeling with experimental complexation-precipitation and ion-flotation data to define the operating windows under which each metal can be separated selectively from a shared industrial matrix originating at the Almalyk Mining and Metallurgical Combine (Almalyk MMC). FactSage 8.2 modeling places Dy?O?(s) precipitation above pH 7.5 across the full potential range, TeO?(s) within pH 5-8 at Eh 0.5-0.7 V, and molybdenum oxide phases across three distinct fields depending on pH and Eh, with metallic Mo(s) recoverable only below Eh ?0.2 V at pH above 9. Copper is treated through two complementary routes: reductive complexation-precipitation with thiourea and ascorbic acid, which removes 93.4% of chloride at 50 °C under a 1:3:1 TU/AC/Cl? ratio, and diethyldithiocarbamate (DEDTC) ion flotation, which extracts 98.6-99.5% of copper at pH 5.0-5.5. Nickel co-recovery by the same flotation route reaches 54.0-74.0% at pH 6.0. These windows are combined into a sequential separation scheme that avoids the indiscriminate co-precipitation typical of lime neutralization. The results give a thermodynamically grounded basis for staged recovery circuits applicable to similar copper-smelter effluents.