Abstract: With the implementation of the Standards for the Discharge of Industrial Pollutants in Tin, Antimony, and Mercury Industries (GB 30770‑2014), stricter requirements have been imposed on arsenic discharge in industrial wastewater (<0.5 mg·L⁻¹), making the development of cost‑effective deep arsenic removal technologies an urgent need for the industry. This study addresses the challenge of deep treatment for slag washing water from a smelting plant (As≈150 mg·L⁻¹, pH 6–7.2) by systematically investigating the arsenic removal efficiency and mechanism of the “internal electrolytic oxidation‑flocculation precipitation‑carbon stone fibre adsorption” combined process. The results show that single internal electrolytic oxidation (iron‑carbon filling, iron‑carbon ratio 3∶1) or lime flocculation precipitation can achieve arsenic removal rates of over 98%, but due to the solubility equilibrium of precipitates such as calcium arsenate, the effluent arsenic concentration remains 1–2 mg·L⁻¹, failing to meet standards consistently. Through process coupling, subsequent treatment with carbon stone fibre materials with high specific surface area and selective adsorption capacity can reduce the final effluent arsenic concentration to 0.309–0.348 mg·L⁻¹, stably meeting national discharge standards. The study further explored the effects of key parameters such as iron‑carbon ratio, pH and reaction time, and verified the regenerability of the carbon stone fibre adsorption material. This process combines the advantages of chemical precipitation and physical adsorption, with a simple workflow and low operating cost, providing a reliable technical pathway for the deep purification and reuse of low‑concentration arsenic‑containing wastewater in the smelting industry.

Key words: arsenic removal process, water flushing slag, electrolytic oxidation, flocculation precipitation, carbonate fiber adsorption