HEIRLOOM TECHNOLOGY

[COOKING

WITH ]

TRASH

By Tim Anderson

The Chinese make fuel briquettes from coal dust, farm waste, scrap wood, and a bit of local red dirt.

Known for their ingenious reusing and wasting not, the Chinese make very effective cooking fuel briquettes from waste cellulose and carbon materials, using local clay as a binder. The briquettes are cylindrical with air passages through them.

An expat living in the United States told me he had a water heater in Germany in the 1960s that used the same type of briquettes.

The source materials for the fuel include coal dust, carbon from sawdust, farm waste, and scrap wood. The local red clay dirt is the binder.

HOW THEY DO IT

Sawdust and other carbon-bearing materials such as waste paper are first reduced to charcoal in a furnace. I haven’t yet seen this part of the process.

Coal dust is used as is. The coal is ground to a certain size and mixed with the red clay dirt. The ratio is 80 percent coal to 20 percent clay.

At the same time, the mixture is sprinkled with

38 Make: Volume 11

water from a watering can; enough water is mixed in so that it will all hold together when squeezed by hand. A certain amount of sand or limestone gravel is present in the dirt and doesn’t seem to cause a problem. That’s it!

When completely burned, a “clinker” is left over, which is removed with tongs. Stomping on them easily crushes these clinkers.

They are then often used as what seems to be a decent road surface, as well as good soil for growing crops.

Videos of the briquette maker in action: makezine.com/go/briquette1 makezine.com/go/briquette2

Tim Anderson, founder of Z Corp., has a home at mit.edu/robot.