Brown aluminum oxide and blasting media garnet are widely used types of abrasives in sandblasting for rust removal, yet they have significant differences.
(1) Different origins
Brown aluminum oxide abrasive is an artificial corundum produced by melting and reducing three raw materials-bauxite, coke (or anthracite), and iron filings-in an electric furnace at temperatures above 2000 degrees Celsius, hence its name. It is commonly found in brown and black colors.
Blasting media garnet is made from large blocks of ore extracted from rare ultra-high-pressure metamorphic rocks through a series of processing steps including blasting, crushing, screening, and magnetic separation. It is a natural non-metallic mineral, formed naturally. Its colors include brown, black, red, and green.
(2) Different chemical properties
The main component of brown aluminum oxide is Al2O3, with a content of 95%-97%; the main components of garnet abrasive include approximately 38% SiO2, 22% FeO, 19% Al2O3, and some other components.
Based on their different compositions, the following distinctions in characteristics can be observed:
a. Brown aluminum oxide abrasive has a hardness of approximately 9.0, while blasting media garnet has a hardness between 7.5 and 8.0. In terms of hardness, garnet is not as wear-resistant as brown aluminum oxide. However, when used as a sandblasting abrasive, garnet abrasive can thoroughly remove oxide layers, paint, and oil stains, while also protecting the sandblasted object from scratches. In terms of material protection, garnet abrasive is superior to brown fused alumina.
b. Blasting media garnet has strong corrosion resistance. Due to its diverse chemical composition, its solubility in acids and bases is only 1%, making it inert. However, brown aluminum oxide has better fire resistance than garnet abrasive.
c. There is a significant difference in market price. Since blasting media garnet is made from natural raw stones through crushing and processing, as long as the raw material is of good quality, the only things to consider are the uniformity and cleanliness of the processed particles.
