By Ms. Kimberly A Conrad (Rock Island Arsenal)October 18, 2017
ROCK ISLAND ARSENAL, Ill. - Nearly one year ago Rock Island Arsenal Joint Manufacturing and Technology Center started a project to remove tin pest from more than nine million pounds of tin.
Defense Logistics Agency Strategic Materials experienced a chemical transformation in their tin inventory known as tin pest, or tin disease. Tin pest occurs at low temperatures in storage, when the favored metallic white form of tin decomposes to a nonmetallic gray, flaky form.
Once decomposition begins and tin pest appears, the reaction gains momentum and spreads throughout the inventory, which is why it is also called a disease. Simply put the tin is disintegrating, to the point where it cannot be used or sold to customers.
A team from RIA-JMTC consisting of program management, quality, foundry, laboratory, and packaging personnel developed a process to assist DLA Strategic Materials in reprocessing the diseased, unusable tin. This new process enables the Arsenal to receive the diseased tin from DLA Strategic Materials, remove the disease, and return a 99 percent pure tin. DLA Strategic Materials is then able to provide this material to customers.
Program manager Bill Holgorsen says the process is rather simple. "JMTC remelts the tin, skims off the pest, and pours the material into ingots. Our lab runs a chemical composition to inform DLA on how pure their tin is."
Currently RIA-JMTC is producing 44,000 pounds of tin a month, with a loss of only 5.4 percent. For the next cycle of reprocessing, the Arsenal will be producing 88,000 pounds per month for DLA Strategic Materials.
So far RIA-JMTC has successfully reprocessed 130,000 pounds of tin. With 8.8 million pounds of tin still in inventory, this program could run through the factory for another five to seven years.