Limonite

Limonite or yellow iron oxide is a mineral substance from the Iron Oxide pigments series, with chemical formula FeO(OH).Nh2o.This mineral is also known as Hydrated iron oxide, iron hydroxide and yellow ochre.

Composition and Properties of Limonite or Yellow Iron Oxide

Research shows that this mineral substance often includes a significant amount of mineral iron oxides such as hematite, goethite, akaganeite, lepidocrocite. Limonite is a secondary substance, derived from the weathering of hematite, pyrite and magnetite and other substances containing iron. This iron ore is highly resistant in various weather conditions.

This mineral pigment, which is found in light yellow, dark yellow and orange colors, is resistant to light and has a high covering capacity. It contains a number of water molecules in its molecular structure and has moisture saturation of less than 1. The solubility of Limonite in water is less than 0.3%. Reportedly, the solution of this pigment has a pH. ranging between 3 to 7 and its oil absorption ranges between 25 to 35 in 100 grams of this substance. Thermal operations are performed on this substance in order to eliminate or decrease water molecules in its molecular structure and to enhance the quality of powder and paint.

A diverse spectrum of limonite pigments are provided in lemon ochre, yellow ochre, orange ochre and brown ochre. By combining these colors together and with other pigments we can produce an unlimited number of other colors.

Various Applications of Limonite (Yellow Iron Oxide)

Yellow iron oxide or limonite has been used as a pigment for thousands of years. It was probably used at first on the surface of ancient artifacts and paintings.

Limonite is used in the following industries:

• Paint and Coating Industry:

  The most important application of limonite or yellow ochre is in manufacturing various industrial as well as handmade paints. In many artifacts from ancient Rome and Egypt, this mineral pigment has been used for coating. Also, this substance is applied for producing many shades of cream, beige, etc.

• Tile and Ceramic Industry:

  Limonite is used as pigment in manufacturing the glaze of ceramic tiles and the body of tiles.

• Floor Covering (Flooring) Industry:

  This pigment is applied in producing colored floor covering.

• Plastic Industry:

  Yellow iron oxide can be used in manufacturing colored plastic products.

• Ink Industry:

  One of the main applications of yellow iron oxide or limonite is in producing colored inks. Considering the existence of iron in this pigment, it can be used to manufacture magnetic inks as well. Limonite powder can also be applied in some colored toners.

• Glass Industry:

  Limonite or yellow iron oxide is used in manufacturing colored glasses.

• Prefabricated Cement and Concrete Industry:

  Despite the limited mechanical properties of colored concrete compared to regular ones, yellow ochre or limonite has been used for many years in producing colored concrete and cement. Moreover, the resistance of this substance in long-term has been proven by vast research in this regard.

• Colored Bricks and Asphalt Industry:

  Limonite (yellow ochre) powder is used in manufacturing various types of colored bricks, prefabricated concrete and colored asphalt.

• Cosmetics and Self-Care Industry:

  Due to the high resistance of this mineral pigment to light, its low solubility in water and its high covering capacity, it is used for producing cosmetic products. Products manufactured with yellow iron oxide are very effective in protection against sunlight and insect bites.

• Pencil Producing Industry:

  Limonite powder is used to color the pencil core in this industry.

• Water and Soil Purification Industry:

  Most substances that contain iron can be applied for reducing and eliminating pollutants and pollutions from soil and sewage. Limonite can be used to remove toxic metals such as chrome from polluted water and soil.

• Construction Materials:

  Yellow iron oxide (yellow ochre) powder can be used in producing colored and decorative construction materials.

• Adhesives and Resin Industry

• Brake Lining Industry