Woodworking is a rewarding hobby and profession, but it also produces a lot of wood waste. According to some estimates, up to 84% of the original tree is lost as wood chips, sawdust, shavings, offcuts, and other residues. They are often discarded or burned, wasting valuable resources and creating environmental problems. But do you know that you can turn these wood wastes into charcoal, a useful and profitable product that can be used for grilling, cooking, heating, and industrial fuel?
There are different methods of making charcoal from woodworking wastes, depending on the type and size of the waste. Here are two common methods that you can try at home or in your workshop.
Method 1: Making charcoal from sawdust
Sawdust is one of the most abundant and easy-to-use wood wastes. It can be converted into charcoal by compressing it into briquettes first and then be carbonized into charcoal by a charcoal kiln or a carbonization furnace. If the main wood waste is sawdust, this production process is the most suitable. Here are the steps to follow:
Step 1: Crushing wood waste into fine sawdust
If your sawdust is too coarse or contains large pieces of wood, you need to crush it into fine sawdust. You can use a hammer mill for crushing the big wood chips into sawdust. The size of fine sawdust to make briquettes should be <5mm.
Step 2: Drying sawdust
The sawdust for producing briquettes needs to meet two key points. One is that in the first step, we said that the material must be crushed to a size of less than 5mm, and the other is that the moisture content of the sawdust must be less than 12%.
Therefore, if the humidity of the sawdust is too high, it needs to be dried in the sun or use a sawdust dryer to dry it quickly. The sawdust dryer includes the rotary dryer or the flash dryer. You can choose the sawdust dryer according to the drying capacity.
Step 3: Making sawdust briquette
Sawdust briquettes are made by compressing sawdust under high pressure and high temperature. Sawdsut briquette machine produces hollow sawdust briquettes with the diameter around 5cm.
Step 4: Carbonizing sawdust briquette
Sawdust briquettes need to be carbonized in a kiln or a furnace at a temperature of around 500-800°C for several hours. During carbonization, the briquettes lose moisture and volatile gases and be converted into charcoal.
Method 2: Making charcoal from wood blocks (large wood pieces)
If the wood waste is mainly large pieces of wood, like wood blocks, logs, branches, etc, we recommend the second processing method, which is to carbonize first and then make charcoal briquettes.
Step 1: Carbonizing large wood materials into charcoal
Large pieces of wood waste are easier to place in the carbonization furnace than sawdust. Moreover, the same carbonization furnace can hold much more large pieces of wood than sawdust. Therefore, from the perspective of production efficiency, large pieces of wood are more suitable for direct carbonization.
After carbonization is completed, what we get is original charcoal or natural charcoal. These charcoal pieces can be used directly for barbecue, cooking, fuel, etc. without any problems.
Some customers want these charcoals to be made into specific shapes and sizes to meet different usage scenarios. Then the following processing flow needs to be carried out.
Step 2: Crushing wood charcoal into charcoal powder
Crushing these chunks of charcoal into charcoal powder first makes it easier to shape them into specific shapes and sizes of charcoal briquettes.
Using a machine to crush charcoal can easily produce a large amount of dust, causing harm to the environment and the human body. Ordinary pulverizers with fans are not recommended. We recommend pulverizers with bottom discharging. Before crushing, spray some water on the charcoal, but be careful not to spray too much water, which can greatly reduce charcoal dust.
Step 3: Charcoal powder mixing
If you want to use charcoal powder to make them into specific shape briquettes, in addition to adding water, you also need to add a binder, because the charcoal powder itself is not sticky.
Customers often ask what kind of adhesive is best for making charcoal briquettes. We recommend corn starch and tapioca starch because they are food starches, harmless to the human body, easy to buy, and very cheap.
Some customers will also ask about the formula. Our common formula is about 5 kg of starch mixed with 45 kg of water or heated and gelatinized, and then mixed with 100 kg of charcoal powder and stirred evenly. The formula is not fixed. Customers need to constantly adjust according to the quality of the charcoal briquettes in actual production to find the best formula that suits them.