A flaky layer of iron oxides with a thickness about 1mm formed on the steel surface during the hot rolling process as a result of oxidation process due to the exposure of steel to high temperature in an oxidizing atmosphere.

Economic value:

Mill scale has become a valuable material and a very attractive industrial waste due to its richness in iron (about = 72% Fe) with minimum impurities.

Industrial Applications:

Mill scale can be recycled and used in many industrial fields such as;

Batteries, Cement clinker, Counterweights, Heat conservation, Iron Feedstock, Ferro-alloys, Fertilizer, Friction products, Heavy concrete, Iron oxides, Iron salts, Mineral wool, Paint, Radiation shielding, Road construction and Welding electrodes.

How mill scale is formed?

Due to the exposure of steel to high temperature in an oxidizing atmosphere, the steel surface is oxidized forming iron oxide layer on the surface which is called mill scale.

Although mill scale is a valuable waste, it is undesirable on steel surface as it results in a significant loss of yield of steel, affects the surface quality of the steel product and affects the roll wear and working life. Mill scale can cause issues with next-stage processes; Coatings will chip off as the scale peels off, affects welding and behaves as a thermal and electrical insulator.  Also, the impurities found in the scale, such as oxygen, can release into the steel.  This leads to increased porosity which will weaken the joint. Thus Mill scale is removed, collected and sold for reuse in many industrial applications.

Removal and collection of mill scale

 Mill scale usually separates and falls by process waters used for descaling, roll and material cooling. It is collected with coolant and lubricating oils and normally held in a collection/settling tank. It is subsequently recovered by gravity separation techniques.

Characteristics of mill scale:

Physical Characteristics:

Mill scale is a bluish- black metal powder made up of small particles, flake, and chips. Its physical state is solid and powdered. It has a stable state, insoluble in water and alkalis but soluble in most of the strong acids. It is normally classified as non-dangerous waste material.

Chemical Characteristics:

Mill Scale consists of iron ranging from 68 % to 72 % and a large number of constituents and its composition can change according to the steel plant production. It can contain C, Si, Ca, Na, Al, Mn and other metal oxides.

Our product:

We at Dahab logistics are ready to supply Mill scale worldwide, with full customer support to ensure that all the customers’ requirements are met including quality, quantity, packaging and shipment to fulfil customers’ satisfaction.

For Specifications and Quotation Contact us.