[snip] who can tell me what happens when you try to smelt the galvanized steel common throughout modern products? [snip]
"There are many items we use every day that are made from steel and are recyclable. I have listed some of the more common ones below, along with any treatment requirements before being sent to a remelting facility.
Steel pots and pans – no further treatment
Kitchen Appliances – washing machines, dishwashers, stoves, refrigerators, freezers and microwaves have their electrical motors and wiring removed.
Galvanized steel items – no further treatment; the galvanizing is evaporated during melting.
Steel beverage and food cans – Some soft drink cans such as Coke and Fanta are made from aluminum, so all the cans are passed under magnets which remove the steel cans, the aluminium cans being stored separately. Steel beverage and food cans will have been coated inside with a very thin layer of tin to prevent the steel from corroding which is removed before melting; the tin being sent to a specialist recycling plant.
All the scrap steel is then gathered and compacted into steel cubes and transported to the specialist steel remelt facility.
Smelting of Scrap SteelThis can be carried out using an Electric Arc Furnace or as part of the Blast Oxygen Furnace smelting process. We shall examine the Electric Air Furnace method as this uses 100% recycled steel.
The furnace is a circular steel vessel lined with firebrick which can tilt on its supporting pad. It has a retractable lid containing a set of electrical prongs which when powered, creates an arc between themselves and the scrap, causing it to melt. When tilted, the molten metal can be tapped and poured into a fire proof container and transported to the steel rolling facility.
Fume Extraction and TreatmentA fume extraction system is attached to the lid of the furnace from where the fumes are directed through a treatment plant. Here the harmful particles are removed along with most of the noxious gases. The dust extracted can then be further processed, leaving just steel particles which are fed back into the furnace.
There is also a fume extraction system which draws any fumes and particles from the building containing the electric arc furnace. These fumes are also directed into the fume treatment plant, thus ensuring most noxious fumes and all particulates are removed; protecting the environment, the local population, and the workers, for the microscopic dust particulates are carcinogenic when inhaled."