Have you ever wondered what happens to your iPhone after you trade it in at an Apple store?
On Tuesday, Bloomberg published a report detailing a used iPhone’s journey from the moment you hand it over to an Apple employee. In exchange for a used electronic device, Apple offers customers an Apple gift card that can be used towards new products.
Bloomberg spoke with anonymous sources—some of whom work at the recycling facilities your Apple (aapl) product ultimately ends up—and Lisa Jackson, an Apple vice president in charge of environmental initiatives for the report.
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After trading in a device to Apple, it’s put through several tests to determine if it can be resold on the second-hand market. Devices with too much damage or deemed unsellable are sent directly to one of the several recycling facilities throughout the world.
Apple’s recycling process consists of “the most rigid and exacting” processes when compared to other technology companies, according to the report.
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Apple contracts with various recycling facilities throughout the world, one of which is Li Tong Group. Li Tong is reportedly in the process of building a new facility in San Francisco, set to open this year.
Jackson claims Apple’s effort to reverse manufacture its products result in recycling 85% (by weight) of a device. The industry goal is to collect and recycle 70% of a device.
The recycling process involves 10 steps and some 50 rules each contractor has to agree to and follow. Each operation includes a series of vacuum-sealed rooms “designed to capture 100 percent of the chemicals and gasses released during the process,” the report said.
In 2014, Apple claims it collected enough steel to build 100 miles of railway track.
Linda Li, chief strategy officer for recycler Li Tong, told Bloomberg the company helps other customers repurpose components, such as camera modules for drones or turning old Microsoft Surface screens into displays for New York taxis.
That’s not the case with Apple; the report details how much effort Apple puts into preventing parts from older products being used in fake Apple products.
For example, Apple institutes a “full destruction” policy, meaning all chips and components from recycled products are shredded and rendered unusable instead of being repurposed. Only after a component is completely broken down can its valuable materials such as aluminum, gold, and copper be sold and repurposed.
Apple also requires its recycling partners to remove all Apple logos from the recycled goods.