The old sand produced by the coated sand shell molding line will be sent to the old sand hopper at the top of the roaster after rough sand crushing, magnetic separating, vibrating crushing and the second stage of sand conditioning by using linear sand screen, bucket elevator and magnetic separator.
Under the old sand hopper, the old sand is sent into the roasting furnace by the sand crew feeder equipped with frequency conversion to control the quantity for the high temperature burning .
After roasting, the old sand enters the fluidized bed (the equipment adopts air cooling and water cooling mode, in order to control the temperature of recycled sand, the water cooling pipe is controlled by multiple groups of valves); after cooling, the reclamation sand is transferred by the elevator to the recycled sand hopper.The next stage is to start mixing the coated sand.
New sand and old sand are sent into the quantitative hopper above rolling drum heating furnace by the special elevator. The unloading time of the sand is controlled by the sand temperature, automatic heating in the drum heating furnace to the temperature value (generally in resin softening point + 40℃), then sent to the sand mixing machine (according to different temperature, manual or automatically adding resin, curing agent, calcium stearate, etc. adding silane, dibutyl ester, and others if needed.), the mixed coated sand by rapid crushing, cooling, screening (the purpose of avoid of blocking), is sent to the finished coated sand hopper.
The above process is equipped with the electronic control system and the dust collector, and the emission meets the national standards.