6000 Year Old Furnace Found in Israel
The Journal of Archeological Science reported that a furnace made of tin and clay was found in Israel. It dates from some 6000 years ago. Evidence – including the presence of slag, a glass like byproduct, suggests it was used for smelting copper ore.
Metals smelting belongs to the field of metallurgy. Deltech’s late co-founder Calvin L. Stevenson was a pyrometallurgist with the then Anaconda Company. If you find yourself in western Montana, pay a visit to Butte to see the now defunct open pit mine and visit the Granite Mountain Speculator Mine Memorial. Head 25 miles further east to visit Anaconda, Montana and see the smelter stack, now an historic preservation site.
Most Deltech furnaces are used for ceramic and glass processing, but Cal’s education and experience in metals processing played a significant role when the company began making resistance heated laboratory furnaces in the early 1970s. Fortunately there were better materials available to use in the fabrication of the furnaces than tin and clay, but the early materials and components were a long way from what is available today.
Early refractory came in 8″ x 8″ pieces, which meant only small workspace sizes were possible. Deltech’s first furnaces had octagonal workspaces to approximate a high efficiency round heated zone, and this configuration is used today for various purposes. The early molydisilicide heating elements required for processing at 1600 degrees celsius and above fizzled quickly. Instrumentation consisted of single setpoint temperature controllers and manually operated power controllers. From a historical perspective, it is interesting that transformers were all copper wound; today they most often have aluminum windings.
Furnace and control system design continues to evolve as new materials and improved instrumentation become available. For example, human machine interface (HMI) systems are becoming increasingly sophisticated, allowing real time data recording and monitoring.