This painless condition occurs when the little bumps on your tongue grow long and trap bacteria that live in your mouth -- making the tongue look black and hairy. Causes can include antibiotic use, poor oral hygiene, smoking, drinking a lot of tea or coffee, and not producing enough saliva.
Hello, Jie. The word passivate is a bit troublesome because aluminum cannot be passivated in the same sense as stainless steel; but it can be passivated in the same sense as zinc plating, i.e., with a chromate conversion coating.
The bauxite then has to be purified using the Bayer process, whose development changed the course of aluminium's history. The process occurs in two main steps. Firstly the aluminium ore is mixed with the sodium hydroxide in which the oxides of aluminium and silicon will dissolve, but other impurities will not.These impurities can then be removed by filtration.he process occurs in two main steps. Firstly the aluminium ore is mixed with the sodium hydroxide in which the oxides of aluminium and silicon will dissolve, but other impurities will not. These impurities can then be removed by filtration.