Archaeometallurgy of ferrous artefacts of the Patriótica Iron Factory (XIX century, Ouro Preto, Brazil)

Abstract

The article reviews the metallurgical processes used in the first industrial ironworks operated in Brazil, the Patriótica Iron Factory, from 1812 to 1831. It discusses its impact on the ironmaking plants that spread in Minas Gerais's state during the XIX century. The remnants of this Factory in Ouro Preto were the first industrial site listed by the Brazilian Historic Heritage Authority (SPHAN) in 1938. Vale SA, owner of the site, and the National Historic and Artistic Heritage Institute (IPHAN) authorised collecting samples from two ferrous artefacts found in the old Factory, a hammer and an eyebolt nailed to the remnants of one of the reduction furnaces. The eyebolt's microstructure suggests that this part was produced in the Patriótica Iron Factory, while the hammer's microstructure indicates that this component was not produced in the Patriótica Iron Factory.

Microstructural Characterisation of Ti and V-containing Synthetic Slags Mimicking the Chemical Composition of the Slag Inclusions of Ferrous Artefacts Produced in the Iron Factory of São João de Ipanema (XIX century, Brazil)

“…Depending on the thermal history of the ferrous artefact, the intradendritic precipitation of (Al,V,Ti)-containing iron spinels and the eutectoid reaction might occur in the slag inclusions. For instance, the microstructural characterisation of a XIX century iron hammer 26 "showed an unusual feature: the primary wüstite dendrites suffered partial decomposition into magnetite plates (Fe 3 O 4 ) and ferrite halos (Fe), with the ferrite halos between the primary wüstite dendrite and the interdendritic region. The wüstite decomposition is likely related to the high service temperature at the surface of the forging hammer".…”