Incoming sand and tramp metal.
Many no-bake foundries have focused their production efforts on castings exclusively, and disposed of leftover sand lumps. But, successful foundries that focus on profit margins are constantly looking for ways to reduce costs. When sales are down, cost-saving projects gain more attention, because the operators have the opportunity to incorporate new equipment. Generally the projects that get approved first are the ones with the fastest payback.
Foundries that dump spent sand mixed with tramp metal realize that someday they will have to clean up the site. This black cloud has become a revenue stream for some foundries. When you can clean up the environment around your foundry and make money doing it, everyone benefits. What some foundries have realized is that over the years a lot of valuable metal has been dumped along with the sand.
Didion International Inc., known for sand reclamation and for separating sand from metal, has developed a system to help foundries recover the sand and metal that has been disposed on-site. Both ferrous and nonferrous foundries have reported excellent savings with the Didion system. Since the equipment can run outside, plant floor space is reserved. The process is very efficient and the savings easily covers the low energy requirements. A variable jet burner with a 10:1 turndown ratio dries the sand and metallics. The sand is scrubbed and screened twice prior to discharge. The patented dual chambered design recirculates the screen-overs, to optimize the yield up to 97%. The metal is separated from the sand and thoroughly cleaned before discharging.
Reclaimed sand going back into the sand system.
For foundries that send their sand to approved landfill sites, the disposal costs and new sand purchases can easily justify an in-house sand reclamation system.
In most cases if a foundry generates 2 tph of disposal sand, then sand reclamation should be investigated. For foundries generating 5 tph, sand reclamation should be considered as a viable cost saving project. For 10 tph and higher, the savings or payback can be less than one year.
Didion offers a full range of rugged, low-operating cost machines sized up to 100 tph for chemically bonded sands.