How to Make Charcoal Briquettes: Ingredients and Composition

Author

ngureco

Make Reasonable Income Selling Charcoal Briquettes

Making fuel briquettes is a tedious and messy work not suitable for everyone. If you are one of those people seeking high-paying dirty jobs, then, you may consider making charcoal briquettes to sell to your neighborhood. The demand for briquettes is there and there is money to be made. Once the charcoal briquettes have been made, they are cleaner and smokeless than the lump charcoal; - that is the reason many people like them. You will save a lot of your money by making fuel briquettes for use in your home and in addition you should be able to make a reasonable income by selling excess briquettes to other people in your city.

The messy part in making charcoal briquettes is in crushing and mixing charcoal dust as detailed in the article How to Make Fuel Briquettes – Charcoal Dust – Carbonization and Pyrolysis of Biomass.

Defining Briquettes

A briquette is a block of compressed coal dust, charcoal dust, sawdust, wood chips or biomass, and is used as a fuel in stoves and boilers. Charcoal is not like clay. Charcoal is a material without plasticity and can not be mold into shape without adding a binding material. To form charcoal dust into briquettes, an agglomerating material is added to the charcoal dust and then pressure is applied to the mixture to form a briquette.

How to Make Charcoal Briquettes - Charcoal Briquettes Burning. Image credit:DryPot, Wikimedia Commons. | Source

Charcoal Briquette Ingredients and Composition

The ingredients of charcoal briquettes will usually fall under the following:

1. Heat fuel - wood charcoal, charcoal fines, mineral carbon, coal, biomass, etc.
2. Burning speed – sodium nitrate and waxes. Sawdust can also be used.
3. White Ash Color - Calcium carbonate, lime or limestone
4. Binder – starch. Cement, kaolin, ball clay can also be used
5. Press release – use borax
6. Filler – for adulteration use silica, clay, soil, etc

Heat Fuel

This is what provides the energy. The higher the percentage of heat fuel materials, the better the briquette. Try to get about 90% of heat fuel material for good briquettes that will give you more fire. Get materials that will emit less ash – for example, very fine charcoal fines may have come from tree leaves and have a lot of dust and soil in them and will give more ashes. Larger fines are very good and you just need crush them to appropriate size. You can use wood charcoal, charcoal fines, mineral carbon, coal, biomass as heat fuel material.

Accelerants

The materials used are chemical nitrates especially sodium nitrate. Keep off potassium nitrate and ammonium nitrate for they are dangerous. In fact, you should not use nitrates unless you are a professional. To start with, nitrates are used in making fertilizers and can be expensive in many countries. In India, a kilogram of sodium nitrate is currently costing US$1.00 ex-works and since you need about 3 – 4% in your briquettes, this will translate to a lot of money such that your briquettes may not be priced well to compete with lump charcoal. However, it’s important to note that the nitrates are fuel energy that will also provide heat. If you are targeting high end markets like USA, go ahead and use sodium nitrate as an accelerant in your briquettes for that market is willing to pay more for quality. If you are targeting low end markets in developing countries, forget about sodium nitrate. Instead, use sawdust as accelerant. Use about 10 – 20% of sawdust but remember that un-carbonized sawdust will make your briquettes emit a lot of smoke. To reduce the smoke from sawdust, just partly ferment your sawdust for about five days by just letting the sawdust stay in water for 5 days. Alternatively, you will need to carbonize your briquettes after you have made them.

Briquettes will need accelerants to burn faster unlike lump charcoal because there is a difference in the structure of briquettes from that of lump charcoal due to compaction. As a result, briquettes are not able to absorb sufficient oxygen for faster combustion. Nitrates are oxidants and when heated, they give out oxygen for accelerated combustion of briquettes.

White Ashes

White ash color is very appealing in briquettes. It’s like it stands for quality. When you lit your briquettes in a stove, you need to know when they are ready. This is done by observing that the burning briquettes have turned white. You can only see the white ashes if your briquettes contains sufficient calcium carbonate, lime or limestone. A 2 -3% whiting, lime, limestone or calcium carbonate is sufficient. Whiting, lime, limestone or calcium carbonate have in the past been very cheap products but with the rising fuel prices, the cost of transporting the products have become high. It is because of this that in developing countries they may have to do with charcoal briquettes of whatever ash color. Whiting, lime, limestone or calcium carbonate are not heat fuels but they can lower the burning rate such that the briquettes burns for a longer period but at a reduced fire.

Briquette Binders

Charcoal is a material without plasticity and charcoal dust can not hold into shape without adding a binding material. The best bidder of all times has been proven to be starch. Any starch will do but preferably from cassava. Cassava starch is preferred because cassava tuber and chips are very cheap, the tubers are as good as starch due to high starch content, cassava is easily available to the low income societies, and that the societies still consider cassava as a poor man’s food only lying idle in farms waiting to be used just incase there is drought and food shortage. Corn starch (maize starch), wheat starch, maize flour, wheat flour and potatoes starch can also be used. These are foods and it can be difficult to make sense to a poor man that what he may consider as a delicacy should be used by him to make charcoal briquettes. In any case, the world does not want us to ‘destroy’ our foods in make charcoal briquettes, but then on the other hand, a packet of maize flour is of little value if you can not have fire to prepare the meal.

To use the starch as a bidder, you need to gelatinize the starch. Starch gelatinization is just breaking down the intermolecular bonds of starch molecules in hot water to form a thick paste that will stick the charcoal dust together. In simpler language: just use your starch or flour to make porridge and then use the sticky porridge to stick the charcoal dust or fines together.

A bidder has to be used – there is no shortcut unless you wish to use lignin from biomass material by pressing your briquette material using a high pressure briquette pressing machine.

Starch can be expensive. It can cost a dollar per kilogram. You will need about 5 – 7% starch to make briquettes. A 45 kilogram bag of charcoal fines will need 2 – 3 kilograms of starch which will cost you 2 to 3 dollars. 2 to 3 dollars is a lot of money when you reflect on the fact that a 45 kilograms bag of charcoal in developing countries costs about 10 dollars.

Another good bidder is gum Arabic or acacia gum which is harvested from acacia tree. Acacia tree is very common in semi arid areas especially in Africa Sahel and in particular Senegal, Sudan, Somalia, etc. A kilogram of high quality gum Arabic is costing $2 ex-works in Kenya. If you are to use 5% gum Arabic for your charcoal briquettes, then, this is not cheap either.

Mashed newsprint/waste paper pulp is also a good binder. Other bidders such molasses, cement, clay and tar can be used but the resulting briquettes are not the best.

Press Release

Borax or sodium borate is the chemical to use so that when your charcoal paste is pressed to form a block of briquette, the briquette releases itself from the press. This is only necessary if you are using a high speed and high pressure briquette making machine. If you are using simple press/manual press, this is not necessary. Sodium borate is that chemical that is used in making detergents, cosmetics, buffer solutions, fire retardants, anti-fungal compounds, insecticide, as a flux in metallurgy, as texturing agent in cooking, as well as in enamel glazes. Since borax is used as a texturing agent in cooking, it is assumed to be safe for your barbecue BBQ briquettes?

Fillers

Fillers are substances added to briquettes which add no energy value. Fillers’ value is just to increase the weight, density or volume of the briquettes so that the users/buyers may think they are getting a good value for their money. It is a form of adulteration and only adds ash content. If you feel that lump charcoal is a big challenge in terms of price to your charcoal briquettes, just add some filler to your charcoal briquettes and then lower your prices. Fillers must be cheaper than the charcoal fines/dust you are using. Unfortunately there are very few materials that are cheaper than charcoal or charcoal fines. Cement can be used as filler but it is now expensive than charcoal, clay is cheap but if there is huge transport cost involved to transport it to the site where you are manufacturing your briquettes, then you can rule it out. Sandy soil can be ideal as filler since it’s very common in most places. It is said fillers can prolong the burning period of briquettes but then briquettes with too much filler will be of poor quality.

1. Recipes for Making Charcoal Briquettes

i) 10 kg charcoal dust/fines

ii) 0.3 kg cassava starch

2. Recipes for Making Charcoal Briquettes

i) 40 kg charcoal dust/fines

ii) 4 kg sawdust

iii) 2.5 starch

iv) 1 kg calcium carbonate

3. Recipes for Making Charcoal Briquettes

i) 100 kg charcoal dust/fines

ii) 3 kg sodium nitrate

iii) 3 kg sodium borate

iv) 2 kg calcium carbonate/whiting

v) 7 kg wheat starch

4. Recipes for Making Charcoal Briquettes

i) 10 kg charcoal dust/fines

ii) 5 kg saw dust

iii) 1 kg cassava starch

iv) 0.5 kg limestone

5. Recipes for Making Charcoal Briquettes

i) 10 kg charcoal dust/fines

ii) 5 kg saw dust

iii) 0.5 kg cassava starch

iv) 0.5 kg limestone

v) 5 kg sandy soil

6. Recipes for Making Charcoal Briquettes

i) 10 kg charcoal dust/fines

ii) 5 kg saw dust

iii) 1 kg mashed newsprint/pulp

The best recipe for making charcoal briquettes is the one that work for you. Test different recipes again and again, and when you get the one that work for you, don’t let it go.

Briquette Ash Content

Ash content is the percentage of the ratio of weight of ashes after the briquette has burnt completely to weight of briquette before they are burnt.

Example No 1:

1. Weight of lump charcoal in a 2 liters can = 600 grams

2. Weight of ashes from 1 above after complete burn = 15 grams

Ash content of the lump charcoal = 15/600 X 100% = 2.5%

Example No 2:

1. Weight of lump charcoal in a 2 liters can = 1.5 kilograms

2. Weight of ashes from 1 above after a complete burn = 37.5 grams

Ash content of the Charcoal briquettes = 37.5/1500 X 100% = 2.5%

A two liters can of lump charcoal produces 15 grams of ashes and the same can of charcoal briquettes produces 37.5 grams of ashes and we say the ash content is the same. Why? This is because charcoal briquettes are more compact and has a higher density. The average density of lump charcoal is about 0.4 g/cm³ whilst the average density of quality briquettes is about 1 g/cm³.

Ashes - Charcoal Briquettes and Lump Charcoal

Many people believe charcoal briquettes have more ashes than lump charcoal. This is mostly due to the fact that the weight of charcoal briquettes your stove can hold can be as much as three times the weight of lump charcoal the same stove can hold.

If we can have extra ashes to quantify for the briquettes, this should come from the dirt that is contained in charcoal fines used in making the briquettes, the amount of incombustible fillers added to briquettes, and the fact that most of charcoal dust/fines comes from the weak charcoal (from leaves).

Charcoal Briquettes Burn Slowly

Many people believe that charcoal briquettes burn slowly and are less hot than lump charcoal. This is due to the fact that lump charcoal has a bigger surface area than briquettes and therefore has a bigger ability to provide more oxygen for faster combustion. Making briquettes is labor intensive and due to this most briquettes are made of blocks with bigger sizes than lump charcoal. If you find your briquettes are not burning as fast as you would want them, try breaking them into smaller sizes. Sizes of briquettes in the range of 1”x1”x1” will burn faster but whom do you think will have the time to make such small sizes of briquettes? Fortunately, there are briquettes making machines that can make briquettes of any size. A good briquette making machines can cost $6000 ex-works in China.

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