The American process for the zinc oxide production of zinc oxide directly from oxidized ore was developed in 1851.

American process zinc oxide, also called “ direct ZnO”, results from the reduction by coal, and the products of partial combustion, particularly carbon monoxide, of oxidized zinciferous materials to produce zinc vapour. The zinc vapour is subsequently oxidized.

In the early stages the zinc raw materials used to be oxidized ores (such as Calamines) or roasted sulfide concentrates. Nowadays the industry uses mostly technical grade oxides obtained from refining (essentially de-leading and de-chlorating) the fine fraction of galvanizers ashes and brass ashes. Other zinc raw materials that can be used are : Waelz oxides (after purification), dusts from tyre incineration, zinc carbonate and hydroxide, blowings and metalling residues, off grade zinc oxides.

The zinc raw materials are mixed with coal (anthracite) and smelted in gas heated rotary kilns. The resulting zinc oxide is piped through a dust chamber for elimination of the coarse agglomerates and collected in bag filters for packaging.

American process zinc oxides are particularly well suited for paint, ceramic and rubber industry.

325 down mesh	Max.	0.2
200 down mesh	Max.	0.05
900 C Calcination Loss	Max.	0.5
Water Soluble Salts	Max.	0.1
20 % Acetic Acid Residue	Max.	0.1
Humidity	Max.	0.1
ZnO	Min.	99.0
Fe	Max.	0.02
Pb	Max.	0.50
Cu	Max.	0.0003
Mn	Max.	0.0003
Cd	nil
S	Max.	0.1