Molten aluminium reacts with water (or, water vapour from the air) resulting aluminium-oxyde (dross) and hydrogen gas that dissolves in the molten metal. During solidification of cast, hydrogen causes porous structure of the casted part, that must be avoided. Dissolved hydrogen can be removed (degassing) from the molten aluminium by bubbling nitrogen through the molten metal.
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Nitrogen atmosphere significantly improve the quality of soldering inprinted circuit board production or in other prduction processes where soldering is neccessary. It became especially important since the lead-free soldering became compulsory in most of the developed countries. Nitrogen can be continuously supplied to the soldering operation by a nitrogen generator.
Foods sensitive to oxydation (like roasted peanuts, chips, coffeee) keep their original fresh flavour and aroma if they are packaged in nitrogen atmosphere. No rancid off-flavours develop in storage. To fill up those small packages (but millions of them) needs continuous nitrogen supply.
Self life of fruits in cooling warehouses can be significantly increased by modified cooling house atmosphere. Today, the best technology is the ULO (Ultra Low Oxygen) technology, where fruits are kept in a cooling house, where the atmosphere contains 1-2 % oxygen. This process needs continuous availability of nitrogen gas.
Quality of vegetable oil can be preserved in the manufacturing process, if the contact of air and oil is prevented by using nitrogen as blanketing gas. Additionally, the dissolved oxygen can be removed from oil by nitrogen bubbling.