Fan Du,Ying Zhu,Sisi Chen,Yuwen Deng,Fei Wang,Kai Li,Lei Shi,Xin Sun
The copper smelting industry generates significant gypsum waste, primarily composed of calcium sulfate (CaSO 4 ), which can be utilized as a sulfur source for hydrogen sulfide (H 2 S) production. This study explores an optimized process for H 2 S generation via hydrolysis of calcium sulfide (CaS), produced by vacuum carbothermal reduction of gypsum. The results show that: 1) CaSO 4 is reduced to CaS under vacuum carbothermal conditions, and subsequent hydrolysis efficiently produces H 2 S; 2) key parameters, including reduction temperature, carbon content, and recovery time, significantly influence CaS yield; 3) under optimized conditions (hydrolysis temperature, reaction time, and solid-liquid ratio), H 2 S concentrations exceeded 8000 ppm, and high-purity H 2 S gas was achieved, meeting industrial requirements for further processing. Thermodynamic analysis and characterization of reaction intermediates provided insights into the underlying mechanisms, highlighting the critical role of temperature and phase composition in optimizing H 2 S production. Kinetic analysis further clarified that the hydrolysis process follows a diffusion-controlled mechanism, with the temperature dependence of the reaction rate constant ( k ) aligning with the Arrhenius equation. This optimized approach offers a sustainable pathway for utilizing gypsum from copper smelting, contributing to sulfur resource recovery, waste reduction, and high-purity H 2 S production for industrial applications.
Li Yun,Chang Cong,Jie Yafei,Jin Wei,Chen Yongming,Wan Xingbang,Tang Chaobo,Yang Shenghai
A promising copper–cobalt slag cleaning technique has been proposed, involving employing gypsum wastes as a sulfurizing agent to sulfurize copper, cobalt, and iron and enrich a condensed matte from copper–cobalt slag. This work thermodynamically investigated the phase conversion mechanism in the Cu 2 O–CoO–Fe 3 O 4 –FeO–CaSO 4 –C system, at the same time, calculated the equilibrium of the “matte–slag–gas.” The results show that CaSO 4 can be selectively reduced to CaS without self-decomposition to CaO and SO 2 . Cu 2 O and CoO lost in slag can be sulfurized by CaS to Cu 2 S and CoS. Fe x O y tended to stay in oxides. Whereas, in the “matte–slag–gas” equilibrium system, a matte containing Cu 2 S, CoS, FeS, Fe, Co, and Cu was obtained. In addition, industrial copper flash smelting slag was used to conduct beach-scale experiments to validate the thermodynamic modeling results and detect the copper and cobalt recovery efficiency. The experimental results reveal that more than 92% copper and 94% cobalt were recovered in matte. The sulfur and calcium in gypsum waste transferred to matte and cleaned slag, respectively. Thus, the values in the slag and gypsum wastes can be recycled simultaneously. Graphical Abstract
危险品化学品经营许可证（带存储）