This project officially commenced operation in April 2021, treating tail gases from silver refining and platinum-palladium refining in Workshop 1 of the smelter. These include high-concentration nitrogen oxides from silver dissolution with nitric acid and alkaline waste gas from the platinum-palladium complexation reactor. For the high-concentration nitrogen oxides from silver dissolution with nitric acid, the project employs a two-stage bubbling absorption + three-stage jet absorption + two-stage Venturi scrubbing + two-stage alkaline scrubbing process. For the alkaline waste gas from platinum-palladium complexation, a one-stage Venturi scrubbing + one-stage acid scrubbing process is used. Acidic waste gas from the workshop is collected and treated in a two-stage alkaline scrubbing tower, while alkaline waste gas is collected and treated in a one-stage acid scrubbing tower. The treated waste gas is then discharged through a chimney. The project requires nitrogen oxide emission concentrations to be below 100 mg/m³ and ammonia concentrations to be below 5 mg/m³.
This project officially commenced operation in April 2021. Equipped with an online monitoring system, the workshop generated nitrogen oxides at a concentration of 30,000 mg/Nm³, ammonia at 4,000 mg/Nm³, and hydrochloric acid, nitric acid, and sulfur dioxide at 400 mg/Nm³. Testing revealed that the emitted nitrogen oxide concentration was 40 mg/m³, the ammonia concentration was 1 mg/m³, and no acidic waste gases such as hydrochloric acid, nitric acid, and sulfur dioxide were detected. The project is operating well overall, with no equipment malfunctions.
Following the successful bid for this project (September 2020), the lead-zinc smelter signed a waste gas remediation agreement with our company for the rare and precious metals workshop, addressing the high concentration of nitrogen oxides generated from silver dissolution with nitric acid. Our company employed a two-stage bubbling absorption + four-stage jet absorption + one-stage alkaline spray treatment. The project officially commenced operation in January 2021. Third-party testing showed that the nitrogen oxide emission concentration was 40 mg/m³, far below the agreed-upon requirement of 100 mg/m³. This project received strong affirmation from the client.
