Half of all metal has disappeared

Only about 50 % of the metals we have taken from the earth’s crust are currently being used. This means there is just as much not being used. Nils Johansson has looked and found them and often, they’re above ground.

Johansson, doctoral student in Environmental Technology and Management, has examined where the lost metal went, why there is such a big difference between the amount of metal we excavated from the earth’s surface and the amount used for cans, car bodies, mobile phones, cables, pipes, and much more.

Like the others in his research group, he is concentrating on the metals found in what they call the technosphere i.e., metals that people handle or have handled. Approximately half of those amounts are currently being used; the rest is not.

“In total, there is a large supply in the technosphere that is not being utilized. If we reclaim this supply, we can avoid the instance of metals leaking out into the surrounding environment, and save resources through reducing the need for traditional mining operations,” he says.

He’s found that, as regards iron and copper, there is between 10 and 20 % of the metals in landfills and an equal amount in the residual waste from mines. A small percentage is also found in emissions and leakage into the air, but these are very low concentrations. The rest are metals in “hibernation”: it’s not being used, but it hasn’t been classified as waste, for example abandoned ships, buildings, or underground pipelines.

“Metals in the technosphere are quite widespread, but the concentrations are often higher in the cities since metals are chiefly used there.”

This has also given rise to urban mining, or the city itself as a mine. But Johansson wants to go a step further and would rather talk about technospheric mining, since many supplies are also found outside of cities.

“A few mining companies are currently working actively to reclaim the almost 20 % found in mining waste. But the 20 % in landfills is harder to get at. This is due to taxes, laws, and rules around landfills not being adapted to reclaiming resources; instead they put a stop to it,” he argues.

It’s also important to bring in safety considerations; landfills were previously completely uncontrolled and nobody really knows for sure what’s buried there.

Johansson has followed five projects where reclaiming resources in landfills was tested. The project succeeded were the landfills were to be decontaminated, but not in the remainder of cases.

“There are laws, taxes, and rules that facilitate decontamination. The differences could also be due to the fact that decontamination can be paid for, but it’s more difficult to fund the recycling of materials. Since it’s difficult to estimate the metal content of a landfill, it would also be difficult to calculate the income,” he says.

But recycling companies like Stena Metall are definitely interested in the metals in hibernation.

“Recycling companies occupy a stronger position, and there is room for innovations on the market,” states Mats Eklund, Professor of Environmental Technology and Management.

“In the future, perhaps we’ll have temporary supplies in landfills, a store of resources until we’ve produced technology good enough to take charge of and reuse the materials again. Landfill prohibitions could apply only to materials that produce methane,” he muses.

Monica Westman Svenselius 17-01-2012

Photo: Peter Modin

Related Links

• Nils Johansson  
• Department of Environmental Technology and Management at LiU  
• Stena Metall  
• Mats Eklund