Prospects of utilization of electron beam irradiation technology to augment control of SO2 and other emissions from Chilean copper smelting plants

Analysis of potential utilization of applicable SO2-removal process for reduced-SO2-strength off-gases, including electron-beam irradiation, for incrementally improving overall abatement of SO2/SO3 emissions from existing copper smelting facilities in Chile has been carried out. Off-gases are characterized by SO2 content higher than 3,000 ppm, a complex chemical composition and highly oxidizing conditions, along with cyclical and fluctuating generation, reflecting relatively severe service. Laboratory tests with simulated high-SO2-strength process gas were performed at Polish Institute of Nuclear Chemistry and Technology. Test work proved the technical feasibility of removing SO2 from ultra-high SO2 content smelter gases by E-beam irradiation with ammonia injection. A laboratory unit with flow rate of 20 Nm3/h equipped with electron accelerator of 800 keV beam energy was used. Influence of different parameters on SO2 removal efficiency, like temperature, dose, ammonia stoichiometry and water vapor content, has been established. Tests covered a high SO2 content range, 2,000 to 10,000 ppm. A generic design has been deviced to address system arrangement, performance and control requirements. It encompasses upgrading of in-plant ventilation to the extent required by health standards, together with gas cleaning system based on EB Process. The arrangement of the facilities provides for gathering and treating off-gas from selected fugitive emission sources on a continuous basis, at the same time in-drafting a minimum amount of tramp air. An introductory dry dedusting stage uses activated coke injection in conjunction with a fabric filter to efficiently treat raw gas to remove heavy metals, including arsenic, along with particulate matter. Main conclusion of the two major stages of this work, i.e. experimental tests and engineering oriented studies, is that the EB Process is a simple and appropriate, cost-effective, chemical process that would, on a site-specific basis, optimally augment Chilean copper smelter SO2 emission control as required