Bitumen is usually obtained by distilling crude oil. Such bitumen is called petroleum bitumen or distilled bitumen. Petroleum bitumen is the product of two stages of crude oil distillation in the distillation tower. In the first stage of distillation, light materials such as gasoline and propane are separated from crude oil.

This process takes place at a pressure close to one atmosphere (units). In the second stage, heavy compounds such as diesel and kerosene are extracted. This process takes place at a pressure close to the vacuum. Eventually, a mixture of very fine solid particles called asphaltene remains, which is immersed in a grease-like fluid called Malton.

However, some types of bitumen are obtained in nature due to the gradual conversion of crude oil and the evaporation of its volatiles over many years. Such bitumen is called natural bitumen and it is more durable than oil bitumens. Such bitumen may exist in pure form in nature (lake bitumen), such as Behbahan bitumen lake in Iran and Tirinidad bitumen lake in the United States, or it is mined (mineral bitumen). Bitumen is also known as Uintaite.

Blown bitumen is obtained by blowing hot air into pure bitumen in the final stage of purification. In this process, hot air at a temperature of 200 to 300 ° C is blown through perforated tubes containing bitumen. As a result of this process, the hydrogen atoms in the molecules of bitumen hydrocarbons combine with the oxygen in the air, and by the formation of water, the polymerization takes place. Blown bitumen has a lower degree of penetration than pure bitumen, has a higher degree of softness, and is less sensitive to temperature changes. This type of bitumen is mostly used in making roofing sheets, car batteries, and plating. The abbreviation for blown bitumen is R. For example, 80/25 R bitumen means blown bitumen with a degree of softness of 80 and a degree of penetration of 25.