There are four things that can be a limitation of the decomposition of wood components that occur due to heating in the dry distillation process, namely:

1. The limits A is the heating temperature to 200 ° C. Water contained in the raw material out into steam, so that the wood becomes dry, cracked and bent. Carbon content of approximately 60%.
2. Limits B is a heating temperature between 200-280 ° C. The wood gradually becomes charcoal and distillate begins to be produced. Charcoal color becomes dark brown and carbon content of approximately 700%.
3. Limits C is a heating temperature between 280-500 ° C. At this temperature there will be cellulose carbonization, decomposition of lignin and yield "ter". Charcoal formed black and carbon content increased to 80%. The banding process practically stops at 400 ° C.
4. Limits D is a heating temperature of 500 ° C, a process of purification of charcoal, where the formation of "ter" is still ongoing. Carbon levels will increase to 90%. Heating above 700 ° C, producing only hydrogen gas.

But in general and simple process of making activated charcoal consists of three stages:

1. Dehydration: the process of removing water where the raw material is heated to a temperature of 170 ° C.
2. Carbonization: breaking organic materials into carbon. Temperatures above 170 ° C will produce CO, CO2 and acetic acid. At a temperature of 275 ° C, the decomposition produces "ter", methanol and other byproducts. The formation of carbon occurs at temperatures of 400 - 600 ° C
3. Activation: tar decomposition and expansion of pores. Can be done with steam or CO2 as an activator.

The process of activation is important to note in addition to the raw materials used. What is meant by activation is a treatment of charcoal that aims to enlarge the pore that is by solving the hydrocarbon bond or oxidizing the surface molecules so that the charcoal changes the properties, both physics and chemistry, the surface area increases and affects the adsorption power. The activation methods commonly used in the manufacture of activated charcoal are:

1. Chemical Activation

This activation is the process of disconnecting carbon chains from organic compounds with the use of chemicals. The activator used is chemicals such as: alkali metal hydroxides carbonate salts, chlorides, sulfates, phosphates of alkaline earth metals and in particular ZnCl2, inorganic acids such as H2SO4 and H3PO4.

1. Physical Activation.

This activation is the process of breaking the carbon chain of organic compounds with the aid of heat, steam and CO2. Generally the char is heated in a furnace at a temperature of 800-900 ° C. Oxidation with air at low temperatures is an exothermic reaction making it difficult to control it. While heating with steam or CO2 at high temperatures is an endothermic reaction, making it easier to control and most commonly used.

Some raw materials are easier to activate if chlorinated first. It is then carbonized to remove chlorinated hydrocarbons and ultimately activated with steam. It is also possible to treat wood charcoal with sulfur vapor at a temperature of 500 ° C and then desulfurize with H2 to obtain the charcoal with high activity. In some ingredients activated by mixing of chemicals, a second activation is given to the vapor to provide certain physical properties.

With increasing duration of distillation and increasing the temperature of distillation, resulting in smaller amount of charcoal produced, while the distillation and absorption greater. Despite the increasing temperature of the distillation, the activated charcoal is getting better, the temperature limitation is not more than 1000 °C, because it has a lot of ash form to cover the pores that function to adsorb. As a result the active charcoal absorption will decrease. Furthermore the charcoal mixture and activator are heated to a certain temperature and time. The results obtained, tested its absorption capacity to Iodine solution.