natural bitumen or Asphaltum is a natural asphalt resinous hydrocarbon found in western Iran on 1930. This natural asphaltite is a hard Hydrocarbon and is often called a natural asphalt, asphaltite, uintaite, or asphaltum. natural bitumen is soluble in aromatic and aliphatic solvents, as well as petroleum asphalt. Due to its unique compatibility, natural bitumen is frequently used to harden softer petroleum products. natural bitumen in mass is a shiny, black substance similar in appearance to the mineral obsidian. It is brittle and can be easily crushed into a dark brown powder. natural bitumen is found below the earth's surface in vertical veins or seams that are generally between two and six feet in width, but can be as wide as 28 feet. The veins are nearly parallel to each other and are oriented in a northwest to southeast direction. They extend many miles in length and as deep as 1500 feet. The vein will show up on the surface as a thin outcropping and gradually widen as it goes deeper. Due to the narrow mining face, natural bitumen is mined today, much like it was 50 or 100 years ago. The primary difference is that modern miners use pneumatic chipping hammers and mechanical hoists.
The mineral now known as natural bitumen or Asphaltum was discovered in the early 1860's, but it was not until the mid-1880's that Samuel H. Gilson began to promote it as a waterproof coating for wooden pilings, as an insulation for wire cable, and as a unique varnish. Gilson's promotion of the ore was so successful that, in 1888, he and a partner formed the first company to mine and market natural bitumen on a commercial scale. Originally, natural bitumen was sold as "Selects" and "Fines"; the low softening point ore with conchoidal fracture was known as "Selects". The higher softening point ore with a pencillated structure was known as "Fines". Selects commanded a higher price than Fines because of its better purity, good solubility, and usefulness in the paint, stain, and varnish industries. Time and technology have changed this classification system. Processing of natural bitumen now removes most of the inert contaminants and newer, more powerful, solvents make the higher softening point grades more interesting to the user. Today, natural bitumen is graded by softening point (a rough measure of solubility) and particle size. All grades carry a degree of quality far superior to those first small amounts of crude natural bitumen marketed in the 1880's.
natural bitumen is compatible with Microcrystalline and Paraffin Waxes, Petroleum Resins and Oils, Rosins, Tall Oil Pitch, Vegetable Oils (Linseed, Soya, etc.), Petroleum Process Oils, and Petroleum Asphalts.
The following is a general guide to the compatibility of natural bitumen resin in common film-forming and elastomeric systems. Because natural bitumen compatibility can be influenced by variations within a resin/elastomer class and by other components in a formulation, it is good practice to verify natural bitumen compatibility in the specific formula of interest.