Primary emissions are controlled using a direct evacuation system, whereas the secondary emissions are controlled by canopy hoods or auxiliary tapping hoods. A direct evacuation system (DES) consisting of ductwork attached to a separate hole in the furnace roof draws emissions to a gas cleaner, thereby helping to control CO, NOx, VOC, and particulate emissions. The canopy hood is mainly useful for capturing emissions during charging and tapping. Particulate collection is achieved with a baghouse, or scrubbers and electrostatic precipitators as required. Particulate matter removed from EAF emissions using these cleaning methods is a hazardous waste called "EAF dust."
Cooled and solidified slag is crushed and screened to recover metallics for recycle or reuse and the lower metallic aggregate is used in construction applications. The slag produced in EAFs is either reused or landfilled. EAF dust is conveyed into a gas cleaning system.1
The treatment options available for the 14 elements antimony, arsenic, barium, beryllium, cadmium, chromium, lead, mercury, nickel, selenium, silver, thallium, vanadium, and zinc are as follows15:
1. Transporting the dust to an offsite processor for thermal treatment and removal of zinc, chemical fixation, glassification, or fertilizer manufacture
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You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.