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If you remove the impurities in the used activated carbon, it can be re-used. You can recover up to 80% of its effectiveness, which in practice is 100%, since one seldom uses the carbon to its limit. In theory this can be done as many times as you like. If the carbon
is soft (e.g., peat carbon will degenerate with recycling), the grains become smaller every time. Hard varieties, like coconut or stone coal keep significantly better, and can be recycled hundreds of times.
There are two ways to recycle activated carbon:
1. With heat (thermal recycling)
2. With steam (steam recycling)
Recycling with heat within the industry is done as follows:
1. The carbon is dried.
2. It is then pre-heated so that the impurities in the carbon pores are carbonized.
3. The carbon is reactivated around 700-1000°C, when the carbonized impurities turn into gas and escape from the carbon. This is done in an oxygen-free environment to ensure that the carbon does not ignite. In this way, the pores become empty once again and the carbon can be reused.
It is not unusual for amateur distillers in some countries to heat recycle their activated carbon. The description is taken away
It is done as follows:
Note: the carbon contains mostly fusel oils whose highest boiling point is 138°C. Fusel oils are higher alcohols like amyl, butyl and propyl alcohols and their vapor is flammable.
1. Begin by pouring the carbon into a sieve and rinsing it with hot water from the tap. If the carbon grains are 0.4-0.85 mm, they will go right through an ordinary kitchen sieve when rinsed, so you must get a sieve with a finer mesh or omit this step entirely.
2. Then, boil the carbon in water for 10-15 minutes, to dissolve some of the higher alcohols (already it has a 15-20% regeneration). Boil as long as it smells. Repeat if needed.
3. The carbon is then dried in a deep baking dish or roasting tray. When the carbon has dried, it is placed in an electric oven. Note: keep the kitchen fan on and the window partly open, as the vapor can be flammable.
4. Turn the oven on to 140°C or 150°C and heat up the carbon for 2-3 hours.
5. Turn the oven off and let the carbon cool down - now it is ready to be used again.carbonized.
Remember that the impurities leaving the carbon when it is heated have a very bad smell. Also note that the danger of recycling carbon in the oven is that it can ignite. Carbon made from wood or peat ignites at approx. 200°C and stone carbon at approx. 400°C. Stone carbon can sometimes be recycled in the oven at 300-350°C if one wants to do so.
